€¦ · Organised and hosted by Dates: 28 – 29 August 2019 Venue: Emperors Palace Convention...

Organised and hosted by

Dates: 28 – 29 August 2019Venue: Emperors Palace Convention Centre, Johannesurg, South Africa

ICT Infrastructure 2019 will bring together leading thinkers and doers around the theme

“ICT Infrastructure to fuel the growth of South Africa’s economy”.

www.ictinfrastructure.co.za

Incorporating Infracom and Data Centre Central, ICT Infrastructure 2019 will feature an exhibition of leading companies and a concurrent conference exploring

vital elements relating to the planning, installation, operation, and backup of information and communication technologies.

CONTENTS

energize - April 2019 - Page 1

For DISCLAIMER and COPYRIGHT notice, see the last page of this issue.

ENERGIZE A voice for the IEEESouth Africa Section

ENERGIZE A voice for Cigré in

Southern Africa

ENERGIZEA voice for the South Africa Energy Storage

Association

ENERGIZE A voice for SANEA in

Southern Africa

ENERGIZEA voice for SAPVIA in

Southern Africa

ENERGIZEA voice for EPRI in Southern Africa

Editor: Roger Lilley

Features editor: Mike Rycroft Pr Eng MSAIEE

Investigative editor: Chris Yelland BScEng CEng

Consulting editors:

Max Clarke PrEng

Prof. Naren Gupta BSc(Eng) DTSc MTech PhD MBA CEng

Advertising: Mark Yelland

Design and layout: Elizabeth Lotz

Production manager: Helen Hartzenberg

Published by EE Publishers (Pty) Ltd

PO Box 458, Muldersdrift, 1747, South Africa

Tel: 011 543-7000

Cell numbers:

Roger Lilley 082 569-7495

Mark Yelland 074 854-1597

Mike Rycroft 082 465-8233

E-mail: [email protected]

Web site: www.ee.co.za

April 2019LEAD EDITORIAL ..........................................................................................................3

FRONT COVER STORY .................................................................................................4

VIEWS, COMMENT AND OPINION .............................................................................5

INDUSTRY NEWS ........................................................................................................9

POWER DEVELOPMENTS IN AFRICA ..........................................................................13

RENEWABLE ENERGY

v Determining how quickly solar modules age by Sarah Stankorb, EPRI ....................................................................................14

v Drone-based thermographic imaging offers fast solar farm inspection by Mike Rycroft, EE Publishers ...........................................................................16

v Renewable Energy News ................................................................................ 20

TRANSMISSION AND DISTRIBUTION

v Fault passage indication by means of distributed recloser assets Information by Noja Power ..............................................................................22

v Using differential protection for phase-shifting transformers by T Hensler and F Fink, et al ............................................................................23

v Powering the steel industry Information from Siemens .................................................................................26

v Transmission and Distribution News ................................................................ 28

GENERATION

v Developments in co-generation in sugar mills by Mike Rycroft, EE Publishers ...........................................................................30

v Beware these engine killers by Steven Lara-Lee Lumley, WearCheck .............................................................34

v Generation News .......................................................................................... 38

APPLICATIONS

v Improved energy security at low cost for healthcare facilities Mike Rycroft, EE Publishers ...............................................................................40

v University and medical school receive modern clean energy supply Information from ETW ......................................................................................44

v Application News .......................................................................................... 45

PEOPLE NEWS ...........................................................................................................47

POWER ELECTRICAL ENGINEERING INDUSTRY EVENTS ..............................................48

LIST OF ADVERTISERS ................................................................................................48

Compact, cost-effective ring main unit meets multiple application needs

Aegis 36 is Lucy Electric’s latest product, originating from the very successful Aegis product family. It is specially designed for secondary distribution networks, wind farms and PV power stations with ratings up to 36 kV. This range is suitable for indoor and outdoor environments (see page 4).

Contact Connie Ochola, Lucy Switchgear, [email protected] v

Powered by Precision.

SUPPLIERSSupply of generalengineering supplies, eg. Paint, paint brushes,electric cleaners,turpentine, etc.Agent for Vaisala instrumentsin South Africa

MAINTENANCETransformer and Tap changer maintenance (all types)- Oil leak repairs on transformers- Main cover welding on transformers on site- Re-spray of transformers

Spares sourcing

Oil sampling interpretation and filtration

Corrosion treatment on any equipment

ELECTRICALElectrical testing- Bushing H PF & Capacitance- Bushing X PF & Capacitance- Overall Power Factor and Capacitance- Excitation Current- Leakage Reactance- Ratio- DC Winding Resistance- SFRA- CT’s- Functional Test- DRM

On site repairs of all electricalequipment from 6v DC up to400 000v AC

Workshop repairs of smallelectrical equipment

Substation control earths/portableearthing equipment

TRANSPORTRigging and transport oftransformer and equipment (Factory to site)

Transportation of electricalequipment and hazardoussubstances

CONSULTINGProject leading andconsulting

Commissioning anddecommissioning of plant

NEW INSTALLATIONSInstallation and cold commissioning of new transformersVacuum, oil filling and filtrationStorage solutions for transformersTurnkey projects

Founded in 2002 Hypower Heavy Current Maintenance has become a leading “one-stop-shop” for rigging, installation, maintenance, repair and testing of power transformers in the Generation, Transmission and Distribution industry. With a strong team of experts, skilled service staff, high quality equipment and ISO 9001:2008 processes we are well placed in the industry. We would like to encourage you in person to meet our team and experience our business thrive “Powered by Precision.”

57 Gemini Street, Brackenfell, 7560 Cape Town, South AfricaPhone CPT: +27(21) 982 0059Emergency CPT: +27(83) 428 5989Email CPT: [email protected]

44 Third Street, Booysens Reserve, 2091 JohannesburgPhone JHB: +27(11) 496 1346Emergency JHB: +27(82) 571 0936Email JHB: [email protected]


LEAD EDITORIAL COMMENT

What is Energize?

Energize – the independent power and energy journal of Southern Africa – is a business-to-business journal, published by EE Publishers, eleven times per annum, serving the electrical power and energy sectors of Southern Africa.

Mission StatementEnergize strives to keep readers abreast of the latest technologies, developments, applications and news in the field of electrical power and energy, by the publication of original, relevant, high quality articles, by expert authors. Energize provides a forum of communication for the electrical power and energy sectors of Southern Africa.

The power utility really seems to have its back against the wall. It needs more money. It has received about half of what it wanted in tariff increases and RCA adjustments from Nersa and a lot smaller bail-out from government than it expected. Its primary source of income is from the sale of electricity, but it cannot supply enough to meet demand without running its incredibly expensive open-cycle gas turbines. Revenue from sales does not cover the utility’s costs which have been inflated by the amount it needs to service its mushrooming debt. Eskom needs to urgently reduce its operating costs, address its debt and get its new-build power stations working properly.

A large media contingent was invited to a power station tour and briefing recently. Although Eskom’s invitation did not state which power station we would visit for “security reasons” and, perhaps because Eskom’s invitation did not state which power station we would visit other than to say it was 90-minutes from Johannesburg by bus, many of us thought we would get to see the new Kusile power station in Mpumalanga. It seemed likely since Kusile has been the talking point for some time. After all, this power station, construction of which began in 2011, has only one of its six, 800 MW generating units operating and synchronised to the national grid. Significant cost and time overruns have brought this power station – together with its sister station, Medupi, and the national power utility, into disrepute.

What’s the plan now, Eskom?by Roger Lilley, EE Publishers

Eskom is once again asking South Africans to reduce demand, to use electricity sparingly. The power utility says that about 554 MW was saved during the recent Earth Hour event. But how was that power saved? Did the utility burn less coal? Did the power utility save any money?

However, it was not to be. Instead, once the media were on the busses (three of them), we were told that we were, in fact, going to visit the Lethabo power station near the Free State town of Sasolburg. Although Thomas Conradie, the power station manager, conducted us around the plant with great enthusiasm, this 31-year-old, 3700 MW coal-fired power station which comprises six, 618 MW units and draws 120 000 l of water from the Vaal River every day, was not very impressive, being a far cry from the modern power plant many of us were hoping to see. One wonders why, if the power utility wants to save money, it went to the trouble and expense of arranging

this tour. The three-hour long media briefing which followed the tour could have been conducted – as it usually is – at the utility’s premises at Megawatt Park in Woodmead, Johannesburg.

Although we have been told that two additional units (one at Kusile and one at Medupi) would come on line soon adding about 1200 MW to the grid, and that the utility’s management team has a better understanding of the technical problems at Eskom’s power stations, we heard nothing more regarding the proposed restructuring of the utility. Not even a profile of the “restructuring officer” who would oversee the restructuring in terms of the government’s bailout package. Comments about “holding people accountable” seem empty too, given that everyone knows who the responsible people are: Former ministers of public enterprises, former CEOs and acting CEOs and the former CFO. To date, Eskom and the Department of Public Enterprises have remained quiet regarding the pressing of charges.

So, although we’re grateful that Eskom will attempt to prevent further episodes of load-shedding and despite the day-long visit to Eskom’s Lethabo power station and media briefing, we don’t have any reason to be confident that the institution is really addressing its problems and will soon be able to operate efficiently without further bail-outs or higher-than-inflation tariff increases.

Send your comments to [email protected] v

Roger Lilley

Powered by Precision.

SUPPLIERSSupply of generalengineering supplies, eg. Paint, paint brushes,electric cleaners,turpentine, etc.Agent for Vaisala instrumentsin South Africa

MAINTENANCETransformer and Tap changer maintenance (all types)- Oil leak repairs on transformers- Main cover welding on transformers on site- Re-spray of transformers

Spares sourcing

Oil sampling interpretation and filtration

Corrosion treatment on any equipment

ELECTRICALElectrical testing- Bushing H PF & Capacitance- Bushing X PF & Capacitance- Overall Power Factor and Capacitance- Excitation Current- Leakage Reactance- Ratio- DC Winding Resistance- SFRA- CT’s- Functional Test- DRM

On site repairs of all electricalequipment from 6v DC up to400 000v AC

Workshop repairs of smallelectrical equipment

Substation control earths/portableearthing equipment

TRANSPORTRigging and transport oftransformer and equipment (Factory to site)

Transportation of electricalequipment and hazardoussubstances

CONSULTINGProject leading andconsulting

Commissioning anddecommissioning of plant

NEW INSTALLATIONSInstallation and cold commissioning of new transformersVacuum, oil filling and filtrationStorage solutions for transformersTurnkey projects

Founded in 2002 Hypower Heavy Current Maintenance has become a leading “one-stop-shop” for rigging, installation, maintenance, repair and testing of power transformers in the Generation, Transmission and Distribution industry. With a strong team of experts, skilled service staff, high quality equipment and ISO 9001:2008 processes we are well placed in the industry. We would like to encourage you in person to meet our team and experience our business thrive “Powered by Precision.”

57 Gemini Street, Brackenfell, 7560 Cape Town, South AfricaPhone CPT: +27(21) 982 0059Emergency CPT: +27(83) 428 5989Email CPT: [email protected]

44 Third Street, Booysens Reserve, 2091 JohannesburgPhone JHB: +27(11) 496 1346Emergency JHB: +27(82) 571 0936Email JHB: [email protected]

FRONT COVER STORY


Aegis 36 offers high levels of reliability and operator safety. It is a compact, cost-effective and virtually maintenance-free product. Aegis 36 offers numerous functional configurations insulated in a single robot-welded sealed tank. This robust range has been built for the toughest environments, with an option to convert units from indoor to outdoor, extending its environmental protection rating. All of these enhancements have been achieved whilst reducing the spatial footprint, resulting in a design which is more compact and easy to install.

Operation mechanism

The mechanism consists of one operating shaft and one selector. The operating

Compact, cost-effective ring main unit meets multiple application needs

Information from Lucy Electric

Aegis 36 is Lucy Electric’s latest product, originating from the very successful Aegis product family. It is specially designed for secondary distribution networks, wind farms and photovoltaic power stations with ratings up to 36 kV. This range is available for indoor and outdoor environments, suiting various application needs.

shaft is used for switching on/off (mains or earth) and the selector is used for selection of the mains or earth positions.

Earth and test facility

The cable earth and test facility is an optional feature on the load break switch and the circuit breaker. It is located at the front of the unit for ease of access.

Anti-reflex mechanism

This ensures a time delay between switching operations to allow sufficient time for the main (primary or upstream) breaker to trip and clear a fault.

Cable compartment

The cable compartments are located at the front of the unit with horizontally

mounted DIN 400 Type C bushings for ease of cable connection.

Internal arc withstand

The SF6 gas insulated, stainless steel tanks are fully internal arc rated and this feature is also available on the cable compartments (optional) to ensure maximum operator safety in the event of internal faults.

Gas pressure indicator

A gas pressure indicator is fitted to the tank which has green and red sectors to indicate the minimum permissible pressure for safe operation.

Ranges available

Non-extensible range

This range is available in 3 and 4 functions, for both indoor and outdoor formats. This solution is perfectly suited for integration into compact substations to form standard ring main secondary networks with transformer protection. The range features switching and protection functions.

Extensible RMU range

The extensible range enables the addition of further functions to the left, right or both sides of switchgear installed in secondary networks. This range has 1, 2, 3, and 4 functions insulated by SF6 gas in a single, hermetically sealed stainless steel tank.

Available in indoor (IP41 and IP54) format, these units can be easily extended in any combination on site, without specific tooling or floor preparation, and without the need to transfer SF6 gas. Top extensibility can also be achieved by DIN 400 Type C bushings located on the top of the unit. The busbar connection is earth-screened (non-screened available as option) and is suitable for both indoor (IP41) and outdoor (IP54) installations.

Contact Connie Ochola, Lucy Switchgear, [email protected] vAegis 36

VIEWS, COMMENT AND OPINION


This is particularly true of small to medium-sized businesses, who are more at risk due to their limited ability to maintain security and generate revenue during outages. While many people are turning to generators to get them through loadshedding, soaring petrol prices mean this can be an expensive and not very eco-friendly way to go. In addition, over and above the cost of fuel, generators may not appeal to all businesses and individuals.

Moreover, small businesses and home offices cannot cope with the noise levels that diesel or petrol-powered generators make, as many of these entities are in quiet, residential neighbourhoods, and cannot have staff members or fellow residents disrupted. However, an uninterrupted power supply (UPS) can protect businesses against downtime. A UPS can keep all essential equipment running during loadshedding, and more importantly, can save the expensive electronic equipment that we rely on so heavily.

UPS solutions are also scalable to meet different users’ needs. For example, a UPS for basic home use will allow a WiFi router to run, cell phone chargers to operate, and the safe shut down of a single PC, below 500 W.

For advanced home or basic small office use, there are solutions that will enable a TV and or decoder or game console and surround sound to run. Users would also be able to keep the lights on, if connected to the distribution board, and are between 1000 and 3000 W. In this instance, runtime would be dependent on additional external batteries and the connected electrical load.

For a basic small or home office, there are solutions that will allow between one and five PCs to run, with monitors and the router or switch to allow connectivity. It is advisable to connect printers to a UPS due to power spike during start-up. Again,

Protect homes and businesses during loadsheddingby Riaan de Leeuw, Schneider Electric

Loadshedding is becoming a daily reality in South Africa, and is not only affecting businesses and essential services, but all of us in our homes. Today’s world is a heavily connected one. We live in an age of information and are completely dependent on the internet to function. Without connectivity, business can’t be conducted, and any loss of productivity is significant. Loadshedding is also really hard to plan for, as it happens at various, unpredictable times, and often at the last minute. It is therefore crucial to protect our homes and businesses against sudden loss of power or surges.

users could run between 1000 and 5000 W, depending on extra batteries and the physical load.

There are also solutions to cover advanced small to medium use, which would include one to 20 PCs with monitors, the server, router or switch, and lights if connected to the distribution board. While you would have between 5000 and 20 000 W, the same rules apply in terms of batteries and connected electrical load.

UPSs offers guaranteed power protection for connected electronics, which ensures businesses can keep their doors open and maintain contact with partners and customers. Remember, keeping WiFi up and running rather than having to rely on cellular data during loadshedding gives you a better chance of staying online for longer.

Should power be interrupted, or fluctuate outside safe levels, a UPS instantly provides clean battery backup power and surge protection for sensitive equipment, giving enough time to safely power down non-essential devices and keep critical

business operations up and running. It will also provide battery backup power and protection for equipment such as TVs, security systems, gaming consoles. and mobile devices.

When selecting the right UPS solution for your needs, consider that the electrical power supply source to the UPS should have an output watt capacity 20 – 25% higher than the UPS to allow for UPS charging while supplying at full load capacity at the same time. Moreover, runtime is important, giving an indication as to how long a UPS will be able to power its attached equipment in the event of a power disruption.

Lastly, it is advisable to test all equipment by unplugging the UPS periodically to make sure all attached equipment stays powered.

Every business needs to ask itself if it can survive prolonged loadshedding. If the answer is “no” then a UPS is the answer. It works both as a back-up battery for all computers and regulates the amount of power it receives. When electricity utility provider switches off, the UPS switches on, ensuring your hardware performs a proper shutdown. It also protects equipment from power surges, so no huge fluctuations in supply voltage damages expensive investments.


Riaan de Leeuw



Six months ago, Energize visited Eaton’s factory in Wadeville, Germiston, to see a sophisticated microgrid which had been installed there and to speak to the operations manager about the system. Recently, Energize caught up with Bunty Kiremire, Eaton’s newly appointed senior application leader for microgrid energy systems and asked him about the success of project.

Q1. Has the Eaton microgrid, with second-life batteries, met the expectations the company had for it?

Eaton’s microgrid project started three years ago when the company decided that it needed to improve its energy efficiency and reduce demand-side load. The company managed to reduce its bill by about 40% through the use of energy-efficient lighting, equipment and appliances; and then started looking at the supply side. Eaton has over twelve years’ experience in microgrid technology in the US, so the South African branch decided to investigate the viability of using this technology at its local factory.

Q2. How did Eaton become involved with microgrids?

Microgrids are now prominent in the organisation’s agenda because it sees a natural evolution in the energy sector. What’s happening in South Africa is reflective of what’s happening in the rest of the world and microgrids play a key part of that. Now that the price-points of renewable energy and storage has reduced so significantly, microgrids are an affordable option in commercial applications.

Internationally, Eaton has a strategic focus on microgrids and decided to build one at its own manufacturing facility in Wadeville, Germiston. and built a pilot which consists of two 230 kW rooftop PV panels, 275 kW inverters, a 200 kWh storage battery, a 400 kW diesel generator as well as an electricity supply from the local utility.

Q3. What were the main drivers behind Eaton’s decision?

The first benefit is outage avoidance because the loss of production during

Cutting energy costs with microgridsby Bunty Kiremire, Eaton

As South Africans suffer another round of power interruptions, imposed upon them by the national power utility which is unable to generate sufficient electricity to keep the lights on, advanced technology offers a realistic, affordable and environmentally-friendly solution.

outages is extremely expensive to the company. The second is renewable maximisation because PV Systems have been so commoditised that they are now the cheapest form of energy over the lifetime of the plant. However, when using PV alone any excess is not dispatchable on an unreliable grid. However, power conversion systems, microgrids control systems and Li-ion energy storage systems allow for a riding out of outages so that the plant can keep operating – without the use of a diesel generator – when the utility supply fails. The third driver is maximum demand reduction, and the fourth driver is energy arbitrage (applicable typically to industrial customers who are subject to time-of-use tariffs. This allows them to shift lower cost energy for use during higher cost tariff periods).

Q4. Has the theory proved true in a real-life application?

On paper, the project at the company’s factory in Germiston looked good. The last 12 months of operational data have shown that the benefit is actually better than was originally anticipated. In the original assessment, the cost reduction on energy savings alone through arbitrage and maximisation of solar PV, would give us a payback period of about six years. When the outage avoidance figure was factored in, using six, two-hour outages

per year, the payback period reduced to four-and-a-half years.

The tricky thing with outage avoidance is that it becomes hard to predict over the long-term, but the company has experienced about 23 outages in the last year alone – in one case power was off for two consecutive days in September 2018 – i.e. 16 hours of production loss – which was far worse than the original projection of 12 outage-hours per year and has made the microgrid a valuable investment for the company.

Q5. How has else the company benefited from this installation?

The project has generated a lot of market interest resulting in a pipeline of potential projects being created in south, east and west Africa.

Q6. Does the market understand the microgrid concept?

Initially a lot of education was needed to help potential clients understand the technology, how it works and its benefits. There is a great deal of interest in the use of battery storage for the deferment of upgrades to transmission and distribution infrastructure. Now that people understand that microgrids make economic sense, the discussion has moved to how municipalities, companies and utilities can finance such options. Some clients want to own the infrastructure while others simply want to buy the power the system generates without owning the asset. Where a customer wishes to benefit from long term “power as a service” agreements, the financing options, specifically relating to energy storage systems, are a critical key to open up the market.

Q7. What drives other companies to consider a microgrid?

Availability, resilience or reliability and cost of electricity are the three major drivers for microgrids. Some countries experience up to 500 outage-hours a year. To put that into context, in South Africa the average is about 50 outage-

Bunty Kiremire

Continued on page 7 ...



Renewable energy developers have quietly been raising equity finance through Section 12J companies in order to increase their internal rate of returns and competitiveness in the South African market. This is achieved through a boost to investor’s returns as a result of the up-front tax deduction claimed by investors. By way of illustration, if an individual investor, in the highest tax bracket, invests R1-million into a Section 12J company, he/she will receive (upfront) up to R450 000 from SARS in the form of a tax refund.

The up-front tax refund can be up to 45% of the investor’s total investment. The tax refund over the lock-in period of five years (as required by Section 12J in order to retain the tax deduction), translates into an approximate annual return of 8% in the hands of the investor, this is before receiving returns from the underlying investment and after deducting capital gains tax.

From a developer’s perspective, the additional 8%, enhances the investor’s return on investment, thus allowing the developer to reduce returns to investors to as little as 6 to 8% per year thus lowering the cost of equity to an amount below the prime interest rate. With the lower cost of equity and the up-front tax deduction,

Section 12J: The secret to a more competitive tariffby Jonty Sacks, Jaltech

Section 12J of the Income Tax Act was introduced by Treasury to encourage South Africans to invest in the local economy. This incentive is centred around the formation of a Section 12J Venture Capital Company (“Section 12J company”) which generally invests (similarly to private equity funds) into specific asset classes, be it, renewable energy, hospitality, private equity, mining etc. Once formed, taxpayers are incentivised to invest in Section 12J companies through a 100% tax deduction on the amount which they invest.

developers are able to offer targeted after-tax returns of 15 to 18% per year in the hands of the investor.

Given the lower cost of capital due to the Section 12J incentive, developers can elect to lower their tariff which will improve competitiveness, and/or enjoy a higher return.

The up-front tax deduction, not only provides the investor with a return of

up to 8% per year but also provides the investor with downside protection should the investment fail to perform. This is pursuant to an investor receiving up to 45% of his/her investment up-front. As a way of illustration, the investor in the example above would have invested R1-million, and would only be at risk for R550 000, notwithstanding the fact that the investor would have received a return on the full R1-million invested.

Although the incentive was introduced in 2009, only within the last few years (through multiple amendments to the tax legislation), has Section 12J become very attractive, with anticipated investments for 2019 being approximately R2 billion. Time is, however, running out for the incentive as Section 12J contains a sunset clause, which provides that investors have until 30 June 2021 to invest in Section 12J companies and claim a tax deduction.

Edi tor ’s note: More informat ion regarding Section J12 tax for venture capital companies (VCCs) is available on the SARS website: www.sars.gov.za/ClientSegments/Businesses/Pages/Venture-Capital-Companies.aspx


Jonty Sacks

hours a year. But in Nigeria, for example, daily outages of between six and twelve hours are common. According to the World Bank, Nigerians suffer an average of 4600 outage-hours per year – out of a total of 8750 hours a year. Nigeria has 7 GW of conventional generation, the transmission network can transmit 5 GW; and there is about 28 GW of installed private diesel generation, so

that the key driver in Nigeria is offsetting the cost of diesel fuel.

The weighting differs from region to region, and in South Africa cost of electricity is a key driver followed by availability or outage avoidance.

Q8. Speaking of costs, isn’t it expensive to build a microgrid?

Microgrids actually bring costs down,

...continued from page 6

despite the initial capital expenditure. Industrial microgrids offer a lower cost of ownership through the use of low-cost electricity generation, outage avoidance and reliability. Microgrids also offer frequency and voltage support in private distribution area networks, improving the overall quality of the power.




Chris Yelland

Eskom was faced with two choices a few years ago: Spend money on the maintenance of old power plants to ensure they continue to function optimally or divert the maintenance funds to the Medupi and Kusile power plants to expedite bringing their 800 MW units online.

Medupi and Kusile have six 800 MW generation units each with more modern technology and higher efficiency than Eskom’s older power stations.

If all 12 of Medupi and Kusile’s generation units were functioning optimally, they would add 9600 MW of electricity to the grid. This, in turn, would relieve pressure off Eskom and allow it to decommission old power stations which are expensive to run and maintain.

Eskom therefore decided to divert maintenance funds to finish construction at Medupi and Kusile.

Plan backfired spectacularly

Spending money which should have been used for maintenance on Medupi and Kusile has backfired spectacularly. Instead of having two fully-functional and modern power stations adding 9600 MW to the grid, here is what actually happened:

Only three units at Medupi and one unit at Kusile are in commercial service. The other units are still under construction or going into commission. Instead of producing 800 MW each, these units can only generate 600 MW each before problems arise. The new generation units at Medupi and Kusile have serious problems, with an energy availability factor of around 50%. This should be between 85 and 90%. The power generation units at Medupi and Kusile trip regularly and have worse reliability than Eskom’s older power stations.

Reasons for these problems are corruption and mismanagement at Eskom and its partners.

Eskom’s big blunder: Poor decisions, corruption caused load-shedding

by Rudolf Muller, MyBroadband

South Africa is in the midst of an electricity crisis, which is curiously the result of plans by Eskom to prevent this exact scenario from happening.

W i d e s p r e a d c o r r u p t i o n a n d mismanagement have also seen the cost to build Medupi and Kusile increase by more than R300-billion, reaching R145-bi l l ion and R161,4-bi l l ion respectively. Additionally, the Special Investigating Unit is currently looking into the theft of R170-billion from Eskom: R139-billion of which is related to eleven contractors who helped build the Medupi, Kusile, and Ingula power plants.

With Eskom’s Medupi, Kusile, and Ingula plants costing R334-billion to construct, the R139-billion stolen by contractors makes up a large chunk of the total price tag. Public Enterprises Minister Pravin Gordhan has even suggested that the strategy to divert maintenance money to Medupi and Kusile may have been because corruption is easier with capital projects.

Eskom left in a tough spot

With Medupi and Kusile not functioning as planned, Eskom is in a tough spot.

Medupi and Kusile are not adding nearly enough electricity to the grid to relieve pressure off Eskom and allow it to take older power stations offline. The older plants now need to run optimally, but they have not been maintained properly for years because funds were blown on Medupi and Kusile.

Eskom does not have enough money to increase maintenance and finish Medupi and Kusile, and Eskom now wants to backtrack on its previous strategy – planning instead to focus its finances on maintenance of older plants again.

To get the older plants to run optimally will not be easy, however, because of their deterioration in recent years. Just like a car which is not serviced, these power stations are now seeing more unexpected breakdowns which are costly to repair.

Winter is coming

With an increase in unplanned outages and a much lower energy availability factor in 2019 than in previous years, Eskom will have to perform miracles to prevent load-shedding this winter.

South Africa’s electricity demand is currently very close to the supply, which means any unexpected event can lead to load-shedding. With electricity demand significantly increasing in winter months, Eskom will have to rapidly increase its power generation.

This will not be easy, according to energy experts who suggest that load-shedding will “absolutely” return – it is only a matter of time before the power cuts are back, they say.

Acknowledgement

This article was first published by My Broadband and is republished here with permission.




INDUSTRY NEWS


Minister says regional energy projects “essential” for growth and prosperity

Speaking at the recent DLO Africa Power Roundtable 2019 at the Sandton Convention Centre, Jeff Radebe, the minister of energy, said that regional energy projects and a just transition to a low-carbon economy are essential for the region’s growth and prosperity.

The integration and interconnection of the sub-region, with power and trade initiatives, will improve the lot of the region’s rural poor, he said.

Regarding South Africa’s Integrated Resource Plan (IRP), Radebe said that the final document, which will be released soon, has revised tables for the different technology options for balancing electricity supply and demand. The document is being considered by NEDLAC, he said. Cabinet approval of the IRP will define a tangible plan for energy security which includes the participation of Independent Power Producers (IPPs) in conjunction with Eskom and municipalities.

Eskom alone can no longer meet South Africa’s power capacity requirements, because the Department of Energy estimates that the capacity extension under the IRP will cost in excess of R1-trillion in the period up to 2030, including new power plants, plus the requisite transmission and distribution infrastructure, he added.

Although the unbundling of Eskom has been in the making for years, Radebe said, President Cyril Ramaphosa’s recent announcement has highlighted the importance of moving ahead with the unbundling. Financial institutions have become increasingly averse to pumping funds into Eskom in its current structure, he added.

Energy efficiency is a good way of balancing electr ic i ty supply and demand. However, successful energy efficiency programmes tend to result in the reduction of municipal revenues, which means that municipalities need to be rewarded to the extent of the revenue loss which results from energy efficiency programmes. Energy efficiency technologies, however, have a substantial job creation potential, he said, so financial losses to municipalities must be counterbalanced by demonstrating positive employment outcomes due to energy efficiency programmes.

Radebe said that some municipalities, particularly Metros, which have old power stations should get them functional again,

because they represent an opportunity for municipalities to increase revenues at the same time as improving the country’s electricity system reserve margin.

The amendment of Schedule 2 of the Electricity Regulation Act is intended to enable municipal and distributed generation. Whereas some municipalities are already able to take advantage of the amendment, other municipalities must seek guidance prior to engaging in projects for own generation.

Regarding the culture of non-payment for electricity, the minister said that credit control measures and proper metering systems to maximise revenue collection, the maintenance of a proper balance between dispensing free basic electricity to qualifying customers while charging high users cost reflective tariffs for electricity, are critical elements of a sustainable electricity utility.

The increased demand for electricity cannot be met without a negative impact on the environment as coal is still the primary fuel needed to drive our power stations. On the one hand, as a developing nation, electricity is an instrument to drive social and economic justice. Over the years, Eskom and municipalities have extended their networks and through electrification projects brought quality of life and economic opportunities to many in underdeveloped areas. On the other hand, about 92% of our electricity is generated using the country’s plentiful coal resources. The result is that we generate environmentally damaging emissions. South Africa, Radebe said, will

transition to a low carbon economy, and it will be achieved in a manner that is just.

If one considers the future power system, it is plausible, he said, that it will consist of a combination of energy efficiency, renewables, nuclear, storage and smart grids. The transition to this energy system poses new challenges for governments, system operators, employees and market stakeholders, and we need to confront these challenges head-on.

Over and above the just transition to a low carbon economy, South Africa must anticipate the dynamics posed by the fourth industrial revolution. This is characterised by a fusion of technologies which blurs the lines between the physical, digital and biological spheres, collectively referred to as cyber-physical systems.

We need to shape a future that works for all of us by putting people first and empowering them. In its most pessimistic, dehumanised form, the fourth industrial revolution may indeed have the potential to “robotise” humanity and thus to deprive us of our heart and soul. But as a complement to the best parts of human nature – creativity, empathy, stewardship – it can also lift humanity into a new collective and moral consciousness based on a shared sense of destiny. It is incumbent on us all to make sure the latter prevails by starting with the preparatory work that anticipates this change, Radebe said.


Jeff Radebe

INDUSTRY NEWS


Minister promises no more load-shedding

According to the minister of public enterprises, Pravin Gordhan, Eskom has committed itself to keeping the lights on this winter by adding additional generating units to the grid and limiting the amount of generating capacity lost to unplanned outages.

Speaking to a large media contingent at a hurriedly arranged media briefing at the Lethabo power station in Free State, Gordhan said that Eskom’s so-called “winter plan”, proposed by the technical task team which had been appointed by President Ramaphosa, includes adding two new generators – one at Medupi and the other at Kusile – and returning two older units to service (Kriel Unit 2 and Matla Unit 5) as soon as possible. The older units could be back online as early as late April and mid-May, respectively, he said. Together, these four generators would provide an additional 2250 MW to the grid. To make this possible, an additional R4,5-billion will be spent at Medupi and Kusile to get the next two units onto the grid, according to the power utility’s CEO, Phakamani Hadebe.

Gordhan said that Eskom has, on paper, 46 000 MW of generating capacity, excluding the 4000 MW from renewable energy (RE) produced by independent power producers (IPPs). However, at present, the utility can only supply 29 800 MW, not counting the RE from IPPs. The demand is often higher than this, Gordhan said, leading to Eskom having to request heavy industry to reduce load.

South Africans should be encouraged to use electricity sparingly as this will assist in reducing the likelihood of load-shedding. He said that large energy users will be incentivised to reduce load during periods of peak demand, and that Eskom will manage the network in such a way as to limit unplanned outages to a maximum of 9500 MW.

The minister stressed that Eskom and his department are aware of how critical a reliable, affordable and dependable source of electricity is to the country and that every effort will be made to ensure that load-shedding is not re-introduced unless deemed absolutely essential. In that regard, should rotational load-shedding become unavoidable in the coming months, it will be limited to Stage 1 (a reduction of 1000 MW) and would not last for longer than 26 days over the entire winter period.

Coal-fired power stations should have a lifespan of 50 years, Gordhan said, but to ensure that they operate reliably for so long, intensive maintenance should be done at the power station’s “half-life”. Half-life intensive maintenance has not been done at most of Eskom’s power stations, he said. To address this, Eskom has budgeted R49-billion for maintenance over the next five years.

Jabu Mabuza, Eskom’s chair, said that although some people have suggested that further work on Medupi and/or Kusile be abandoned, this would not be in South Africa’s best interest, since it would leave the country reliant on the older power stations only. Instead, he said, the power utility will invest a further R36- to R48-billion for the completion of these two new coal-fired power stations.

Fu l l supp l y o f e l ec t r i c i t y f rom Mozambique’s Cahora Bassa hydro-electric scheme should be available soon, too, which will help the situation, Mabuza said.

Regarding Eskom’s financial sustainability, Prof. Anton Eberhard, the chair of the Eskom sustainability task team, said that the power utility’s financial problems result from its inability to cover its operational costs and debt-servicing obligations from income received from the sale of electricity.

The utility is over-burdened by debt, he said, adding that new debt is becoming more expensive since it is extended at

higher interest rates due to the utility’s falling credit rating. According to Prof. Eberhard, the only way in which Eskom can become financial sustainable is for it to reduce cost and increase revenue. The team proposed the unbundling of Eskom into three separate dedicated units, Generation, Transmission and Distribution, as it would make each part more efficient and might enable the units to attract investment thereby increasing liquidity, making them less reliant on the state for bailouts. A full report from the sustainability task team is expected by the end of April 2019. v

Pravin Gordhan Jabu Mabuza

Prof. Anton Eberhard



INDUSTRY NEWS


Boosting LV testing capacity at NETFA

The reliability of temperature-rise testing at the SABS’ National Electrical Test Facility (NETFA) in Olifantsfontein received a boost with the installation of six Buck-Boost current injection machines for low-voltage testing, says SABS executive: Laboratory Testing Services Johan Louw.

The Buck-Boost electrical current injection machines will test rising temperature in low-voltage switchgear and control gear to SANS 61439.

Louw says switchgear and control gear are used when energy sources are connected to the electricity grid and the rise of renewable energy; the addition of the Kusile and Medupi power plants and the growth of connection points on the municipal electricity grid will increase the demand for temperature-rise testing.

“The machines were installed and calibrated together with a new electricity supply unit,” he says. “The Buck-Boost machines will allow us to test multiple low-voltage equipment simultaneously while using the same power sources.”

He says the investment in new testing infrastructure has allowed the SABS

to optimise testing times and improve reliability.

“We can now test low-voltage equipment in two to three days, as opposed to a week.”

Lucas Monyai, senior manager at NEFTA, said the laboratories are SANAS accredited and provide testing services

in four technical areas by means of the the short-circuit laboratory; the high-voltage laboratory; materials installation laboratories and distribution technology services.

He says the nature of low-voltage stress tests required exposure to duration testing and that NETFA “excels” in tests such as for radio-influence voltage (RIV).

The investment in new equipment forms part of an SABS turnaround strategy aimed at improving conformance testing services.

The National Electrical Test Facility, which has been conducting testing on electrotechnical equipment, products and appliances since 1990, is the largest independent testing facility for power utilities and the electrotechnical industry in Africa. It is situated next to Eskom’s HVDC Apollo converter station in Olifantsfontein, Gauteng, which allows NETFA to draw high-voltage DC power from the national grid.

Contact Nils Flaatten, SABS, Tel 082 409-2020, [email protected] v

We make microgrids work.*

* The microgrid in Wadeville, South Africa,includes the �rst deployment of Eaton'senergy storage system in Africa. It usessecond life electric vehicle batteries toincrease resilience, provide higher levelsof energy independence, support gridstability and reduce energy costs by up

to 40 percent. A similar sizedmicrogrid could provide energyfor 230 community homes.

To learn more:Visit our stand at African Utility Week,stand #G32AGo to Eaton.com/wadevillemicrogrid

We make what matters work.

INDUSTRY NEWS


Cummins, a 100-year old corporation of complementary business units which design, manufacture, distribute and service a broad portfolio of power solutions, launched its state-of-the-art premises in Waterfall City, Midrand recently. Dubbed the “Power Hub”, the facility demonstrates the company’s confidence in the Southern African region and supports the company’s aspiration to be Africa’s preferred power solutions provider.

The 15 355 m2 Power Hub houses the company’s regional headquarters, its Master Rebuild Centre (MRC), Africa Learning Centre and Gauteng operation centre. Racheal Njoroge, the managing director for southern Africa, said the architectural layout of the building was designed to adopt the company’s “Smart Office” concept to create a space that enhances internal collaboration, encourages engagement and a solution-orientated approach.

The company’s relocation from its Kelvin and Longmeadow offices to the Power Hub provides a suite of products and

Energy association makes changes at the top

capabilities all available under one roof. The central hub, providing power solutions for customers across the Southern Africa region, provides technically advanced expertise from mining, power systems, automotive and technical training. The facility also provides industry with a 2600 kW AVL Dyno Test Cell which will test some of its largest engines to full power; a precision-driven spray booth large enough to accommodate the largest engines’ paint applications and an environmentally advanced water purification plant, an efficient waste water treatment system which recycles 80% of water used in the MRC.

The facility, being a part of the company’s distribution business unit, also focuses on sales and aftermarket servicing. The MRC continues to be a focal point of its support to the mining industry, providing rebuilt engines which ensure customers enjoy a reliable and consistent supply of engines for uninterrupted operations.

Contact Siboni Tsabedze, Cummins, Tel 011 451-3400, [email protected] v

Company celebrates 100 years, opens new HQ

The South African National Energy Association (SANEA) has announced the appointment of a new chair and a new secretary-general. Kiren Maharaj will take over the reigns from Brian Statham after his tenure as the secretary-general of SANEA from 2000 to 2006 and as executive chairman from March 2007 – 2019. Wendy Poulton has been appointed secretary-general of SANEA.

Kiren Maharaj is a dynamic leader with more than 20 years’ experience at strategic, operational and management levels. Operating as an executive in Africa’s foremost utility, she has been involved in many game changing initiatives across multiple technical and economic functions of the energy value chain. She was appointed Managing Director of Gibb Power and EDF in February 2019. She has been a director of SANEA since 2017.

Brian Statham has some 40 years of experience in energy and has been involved in construction (coal, hydro and nuclear), operations, research, product ion planning, investment planning, project development (coal, hydro, LNG, natural gas, nuclear) and strategic planning, predominantly in the area of power generation.

He served two terms as an officer (trustee) of the World Energy Council, the chair of its Studies Committee and a member of its Communications, Finance, Programme and Remuneration Committees from 2010 to 2016. In 2016, he was elected as an honorary officer of the World Energy Council. He has served on a number of governmental

task forces and committees dealing with energy matters, including a two-year term as a member of the Ministerial Advisory Council on Energy from February 2015. In recognition of his many years of involvement with the association, Statham was awarded honorary life membership in 2019.

Wendy Poulton is currently the general manager for organisational strategy at Eskom. Her main area of technical expertise is in the energy field where she has worked for more than 25 years. She has held various roles in Eskom in R&D, environment, sustainable development, climate change, safety and strategy and risk.

She holds an MSc from the University of Pretoria, has completed the MAP at Wits Business School, and the Global Executive Development Programme

at GIBS. In addition, Poulton holds a diploma in strategy and innovation from Oxford University’s Said business school.

Kiren Maharaj Brian Statham

Wendy Poulton


energize - April 2019 - Page 13energize - April 2019 - Page 13

Auto-reclosers improve reliability in Nigeria

Noja Power recently supplied Nigeria’s electricity utility, Ikeja Electric, with its OSM reclosers for a pilot on the country’s 33 kV distribution network. According to the utility ’s spokesman, the radial nature of feeders in its network makes it difficult to identify fault locations. The installation of pole-mounted auto-reclosers on a 17 km, 33 kV line carrying 9 MW of load, has reduced outage times from 16 hours to under a minute, dramatically improving the network’s performance, he said. v

Risk insurance for solar energy

South Sudan has received a record $27,62-million in commercial risk insurance cover through the efforts of the South Sudan government, the African Development Bank and the Africa Trade Insurance Agency (ATI). About $5-million has been ring-fenced for solar energy at rural clinics and police stations. ATI provides risk cover to facilitate investments in the electricity, gas, water supply and financial and insurance sectors. $60-million will be in hard currency and $40-million for spare parts, food, pharmaceuticals and refined products. v

Financing for off-grid and mini-grid connectivity in Africa

Energy industry stakeholders have called for a restructuring of the financing mechanisms enabling the development of off-grid and mini-grid connectivity in Africa. The African Development Bank finances the off-grid and mini-grid sector through its sponsorship and anchor investment in the Facility for Energy Inclusion (FEI), a $500-million debt financing facility targeting small scale renewable energy projects. Despite Africa’s significant energy resources endowments, close to 600-million people on the continent are still without access to electricity. v

Banks partner to implement electricity regulatory index

The African Development Bank and KfW Development Bank will be partnering to accelerate implementation of recommendations contained in the 2018 Electricity Regulators Index (ERI) report for Côte d'Ivoire’s energy sector. Launched in June 2018 during the Africa Energy Forum (AEF) in Mauritius, the ERI is a diagnostic tool that highlights key areas in regulatory design and practice in Africa’s energy sector. The 2018 ERI identified 13 key regulatory gaps across the 15 ERI participating countries, including Côte d'Ivoire. v

Solar powers Senegal

The Senegalese government and the World Bank’s International Finance Corporation have agreed to fund solar projects with combined installed capacity of 60 MW. The projects are to be built by Engie in the Kaolack and Touba regions of the country. Half of Senegal’s population has no access to electricity, and this project is expected to provide electricity to at least some of them. This long-term private-public partnership will be the first independent power producing project in the country, the company’s representative said. v

Somalia to receive €1-million from Italy

The Italian government will provide €1-million to the Multi-Partner Somalia Infrastructure Fund. The fund is one of the financing windows under the Somalia Development and Reconstruction Facility of the New Deal Compact for Somalia which aims to accelerate Somalia’s economic recovery, peace and state building, through rehabilitation and development of the country’s infrastructure. This is expected to enable economic growth through investment and job opportunities. v

Accelerating private sector development

T h e A f r i c a n D e v e l o p m e n t Bank and the governments of Mozambique and Portugal have signed a Mozambique-specific Memorandum of Understanding for the implementation of a financing platform, involving the Bank, Portugal, Angola, Cabo Verde, Guinea Bissau, Equatorial Guinea Mozambique and Sao Tome and Principe, called the Lusophone Compact. The Compact will provide risk mitigation, investment products and technical assistance to accelerate private sector development in sectors which cover renewable energies, agribusiness and agricultural value chains, water and sanitation, infrastructures, tourism and ICT. v

Energy minister to join AEF2019

Aziz Rabbah, Morocco’s minister of energy, has a vision to collaborate with other African nations on large-scale energy projects. Rabbah will be taking part in the Country Spotlight session “From Morocco to Africa” at the event. He will address how the Moroccan government aims to forge deeper ties to support large scale solar solutions across the continent, engaging both public and private sector at the various levels of project preparation. v

More solar power for Ghana

Redavia has been selected to build a 756 kW solar farm at a natural mineral water production facility in Ghana’s eastern region. The deal provides immediate savings for both the bottling company and the environment, since solar power creates no CO2 emissions. The mineral water is drawn from the water table 60 m below ground level and contains no additives, the company says. The company will own the solar power plant at the end of the contract, its CEO said. v


RENEWABLE ENERGY

Solar plant owners and operators seek to predict performance decades into the future, but long-term data are limited. The solar industry is still relatively young, with 90% of capacity deployed in the past seven years. In addition, module designs and components continually change. A better understanding of degradation rates can improve confidence in technology, reduce investment risk, and lower costs.

In a three-year project under the US Department of Energy’s Solar Energy Technologies Off ice PREDICTS2 programme, the Electric Power Research Institute (EPRI) is studying PV module life expectancy and ways to improve predictions of degradation rates.

“Anyone with a financial stake in solar power plants is interested in greater certainty in how modules perform over time,” said EPRI’s senior technical leader, Cara Libby, who is leading the research. “Our work is aimed at developing more reliable tests for evaluating the lifespan of solar technologies, so that companies can make these investments with greater confidence.”

EPRI is examining how accelerated aging tests mimic degradation observed in PV plants that have operated for many years. This involves determining the optimal set of conditions for module testing. Dr Michael Bolen, who manages EPRI’s research on solar generation, points out that many solar module test regimens are borrowed from the semiconductor industry and are effective at screening for certain failures in the first few years of a module’s expected 20-plus year life. They are not effective at predicting life expectancy.

At the Southeastern Solar Research Centre, researchers subjected module batches to standard accelerated ageing tests listed in International Electrotechnical Commission (IEC) 61215 and Qualification Plus, which

Determining how quickly solar modules age

by Sarah Stankorb, EPRI

When engineers consider the development and procurement of solar energy plants, they typically ask questions: Which solar photovoltaic (PV) modules will perform best in our climate? Which are most likely to continue producing energy well into the future? What certifications, specifications, or performance tests should be requested from module manufacturers? On what science do manufacturers determine their products’ claimed longevity?

include various temperature and humidity cycling protocols. The IEC batch exhibited no decrease in power output. In contrast,

modules at a commercial solar power plant under observation experienced a 5% decrease in power over five years.

Fig. 1: The PV modules in this array at the Southeastern Solar Research Centre were subjected to accelerated ageing tests before being installed outdoors.

Fig. 2: Researchers conducted electroluminescence imaging on PV modules at this commercial PV plant to better understand the link between module defects and power degradation.


RENEWABLE ENERGY

The Qualification Plus batch exhibited a reduction similar to what is typically observed at commercial plants after a few years of outdoor exposure.

Based on these accelerated tests, modeling, and performance measurements at other plants, researchers seek to develop calculations for estimating module degradation rates in any climate as a function of exposure to environmental stressors.

“We are trying to better understand how specific stressors lead to degradation,” said Libby. “This can help us define better tests for predicting susceptibility to failures from year 4 to year 30 of a module’s life.”

“New PV modules and other innovations in solar technology enter the market on a regular basis. It is impractical to wait for 20 years of field observations to accurately gauge life expectancy and degradation rates,” said Dr Bolen. “Improved accelerated ageing tests are one of many emerging techniques to bolster confidence in new technologies.”

The research also may help answer this ongoing question for the solar industry: Do modules degrade at a steady rate over their life, or do various aspects of degradation compound to accelerate degradation?

EPRI is considering additional accelerated aging research on modules from several manufacturers, in different climates, and from power plants of various ages. EPRI also is preparing a report to help solar plant operators optimize maintenance and improve techniques to identify failed or degraded modules. This material is based upon work supported by the US Department of Energy’s Office of Energy Efficiency and Renewable Energy (EERE) under Solar Energy Technologies Office (SETO) Agreement Number DE-EE0007137.

Are cracks in solar cells a big deal?

As part of EPRI’s research under the US Department of Energy’s PREDICTS2 programme, EPRI conducted electroluminescence tests on PV modules to better understand the link between module defects and power degradation. In late 2016, researchers imaged modules at an operating commercial PV plant. A year later, they imaged the same modules again, observing 20% more solar cells and modules affected by busbar defects. This surprisingly large increase warrants further investigation of root causes along with continued monitoring to assess performance impacts.

In a separate analysis, researchers took electroluminescence measurements on modules at various points during lab-based accelerated aging tests, then imaged the modules again after they were installed outdoors for further monitoring. The first set of field images had 9% more defects than the final lab images – possibly attributable to handling during installation. The results demonstrate PV cells’ susceptibility to cracking and point to more research to determine whether and how the cell cracks affect the modules’ long-term safety and power.

Contact Michael Bolen, EPRI, [email protected] v


RENEWABLE ENERGY

The common belief is that solar requires very little to almost no maintenance at all. This statement turns out to be true, but at the same time can be very misleading. Solar is an investment that is likely to last 20 to 25 years. In order to calculate an accurate return on investment, one must account for operation and maintenance (O&M) issues, as well as understand them to develop procedures for dealing with these issues in the most efficient and cost effective way. This is why the statement that solar requires little maintenance can be misleading. If the margins on the solar project are very low, and O&M costs are underestimated, this could result in an inaccurate expected return on investment, and the results could be economically disastrous.

Once a fault or defect has developed on a solar panel, other than soiling, cabling or connection problems, there is little that can be done to correct it, and the O&M decision will reduce down to when to replace the panel. Ongoing monitoring

Drone-based thermographic imaging offers fast solar farm inspection

by Mike Rycroft, EE Publishers

Many large ground based PV plants are now ageing, and are subject to increasing faults and failures, as well as deterioration due to aging and inspection and maintenance needs are increasing . Detection of such failures is difficult, taking the large number of panels into account. Aerial thermography and photography using unmanned vehicles, combined with digital twinning, is a possible solution to the problem.

of the condition of the solar panel and analysis of data will allow replacement decisions to be optimised.

PV faults and detection

Faults may be classified as panel faults, and balance of plant (BOP) faults, such as cabling , connection boxes, inverters and other plant. BOP faults may affect individual panels or string performance. Detailed fault detection or performance measurement would require onsite measurement of panel performance characteristics, which would normally mean demounting the panel. Mobile test laboratories have been developed which can perform onsite tests on panels, but this requires demounting the panel and can be costly and time consuming. Many panel faults can be detected by visual imaging or by thermographic imaging means.

Thermographic imaging and analysis

Through the use of IR imaging, faults

and damage that are otherwise invisible to the naked eye can be seen in the form of hot-spots. Thermographic analysis or imaging (TI) makes use of specialised infrared cameras to identify parts of the installation, which could be strings of panels, individual panels, or individual cells, where the temperature is significantly different from the surrounding areas. Temperature differences are indicative of faults or defects. Under operating conditions, the current flowing in the panel causes a temperature rise which will vary according to the state of the component. Faults will cause both hot spots and dead areas on an installation, which thermographic analysis will highlight. Fig.1 is an example of thermographic image of a solar farm, showing both healthy panels and panels with faults. A healthy panel will exhibit a uniform temperature profile.

Typical panel faults which can be detected by this method include:

Bulk faultsl Offline string: A whole string of panels

is disconnected and not producing power. he string will have a lower temperature than the rest of the installation.

l Offline panel: A single panel is disconnected from the system and not producing power.

l Faulty connections or strings.

Individual panel faults

These are identified by “hot spots” on the panel surface. A hot spot is a PV cell or a group of cells operating at significantly higher temperature than the rest of the cells of the panel, This behaviour could be due to the following reasons:

l Deterioration of the PV current due to dust or dirt accumulated on its surface.

l Damaged or broken up cel ls Fig. 1: Thermographic image of a solar farm (heliolytics).


RENEWABLE ENERGY

(mechanical damage, break of protective layers).

l Partially shaded cells (usually met in residential installations).

l Shunt resistance problems.l Resistive heating due to improper cell

interconnect.l Errors in the laying out of the electrical

installation-bypass diode etc.l Faulty bypass diodes.l PID effect: The potential induced

degradation phenomenon, first observed in the seventies, leads to a sudden decrease of PV panel efficiency. The general mechanism of PID is that voltage bias related with leakage currents pass from silicon active layer through the glass to the grounded module frame.

A hot-spot initiates in a cell when, due to one or more of the above mentioned reasons, a change in the electrical behaviour of the cell takes place. The defective cell is forced to pass a current exceeding its generation capabilities, and it becomes reverse biased, entering the breakdown regime and subsequently sinking power instead of sourcing it. The cell behaves as a purely ohmic load, draining energy produced by the neighbouring cells.

Visual inspection or colour imaging

It has proven useful to capture visual images (colour) as well as thermographic data. Visual images can reveal damage to panel surface as well items such as snail trail defects (delamination). Colour images also help software identify the root cause of issues at the module level. For example, soiling and cracking issues may appear similar in a thermal image, but a colour image makes it easy to distinguish them [5].

This inspection process may lead to the detection of damage to the PV panel or panel covers, may be categorized as follows:

l Breakage of the glass protective surface.

l Bubbles and/or tears to the polymer cover of the backsheet.

l Corrosion of metallic frames.l Damage to the panel insulation.l Failed solder bonds of the PV cells.l Delamination.

Imaging is non-destructive and non-invasive, and can be to inspect the solar panels under load, so no shutdown is required. When used properly, thermal

imaging will show accurate temperature differences between cells or within a single cell that allow identification of faults at an early stage.

Inspection methods

Visual and thermographic imaging can be applied in two ways:

l Ground-based: Suitable for small installations and for balance of plant such as combiner boxes, junction boxes and other items normally located under the panels. Ground based imaging also allows the rear of the panel to be inspected, and can be used for follow up on faults indicated by aerial methods. Usually

a single panel or small group of panels is inspected at a time. This method is generally used at the moment. Ground based imaging limits the angle at which a panel can be studied.

l Aerial-based imaging: This method uses either manned or unmanned craft, and allows the capture of data from a large number of cells in one image. It is very suitable for large Installations as images can be taken rapidly, under the same conditions for all panels.

The use of unmanned aerial vehicles (UAV) or drones allows closer inspection and better control over the thermographic

Fig. 2: Drone-based inspection (Workswell).

Fig. 3: Picture-in-picture feature [8].


RENEWABLE ENERGY

capture process, as well as reducing the cost significantly. Infrared cameras on UAVs are very easy to position at the right distance and angle to capture the optimum image. According to published information, a drone can survey 4000 panels in about five minutes, while a human inspection would take more than eight days at a rate of one panel inspection per minute. Drone capabilities capabilities include remote sensing with LiDAR and infrared (IR) technology, high-resolution photography including UV and other spectral, and HD video.

Drone based thermography allows a realtime analysis by connecting the camera to a ground based analyst, who can guide the pilot as to which panels need closer attention or image recording from a different angle. DBT allows the angle at which the panel is inspected to optimised, as the camera is not fixed but can be rotated.

Some of the ways in which drones aid in thorough, cost-effective solar utility inspections are [2]:

l Identifying malfunctioning units in an array.

l Performing preventive maintenance. Panels, mounting systems, wiring, monitoring equipment, and other plant components can be visually imaged for dust and dirt, snail trails, leaves, corrosion, defects, cracks, and water or insect intrusion.

l Monitoring vegetation to keep foliage from casting shade on strings.

l Detecting equipment that may be in danger of overheating (combiner and junction boxes, inverters).

l Assessing damage following wind, seismic, flood, fire, or electrical storm events.

l Inspecting transmission lines.l Monitoring fencing for security

purposes.

Drone inspections can generate hundreds or thousands of images per site. However, the consistent geometry of PV systems allows for the separation of modules and the use of artificial intelligence to diagnose module defects, while simultaneously assessing and comparing the hierarchy of subsystems such as module versus module or string vs. string.

Capturing the images is only one part of the process, the second is to analyse it. It is not necessary to inspect each image to identify problem areas, as software is available which can automatically

identify specific problems. Using GPS it is able to automatically locate where the problem areas are. This is made possible by “geotagging”of each thermographic image, so that processing of captured date will indicate precisely which solar panels need attention. The software allows selection of temperature ranges to be used in the search, so that only items that exceed the preset level are tagged [4].

Some cameras combine top-notch image quality with advanced features like wireless Wi-Fi connectivity with a tablet and test-and-measurement tools. These wireless connections make a huge difference. Another feature available is the picture-in-picture feature. This overlay of a thermal image over the visual image allows better localisation of hot spots. To optimise time savings, drone data capture should be matched to the specific management goal, such as identification of off-line PV source circuits or module-level cell defects [4]. The Enertis organisation is using drone based thermography for solar analysis on South African installations.

Digital twinning as a maintenance tool for ground-based solar.

How can the massive amount of information collected by photography and thermography, be managed and be put to use? A method that is gaining acceptance in other sectors of the power industry is “digital twinning”. Digital twinning consists of the mapping of physical assets onto a digital platform. For the energy industry, this could be a solar farm, nuclear facility or traditional coal plant. The digital replica uses data from physical assets, for instance, the data acquired from the thermographic analysis, or real time data from the inverters or other items at the solar farm,

to analyse its efficiency, condition and real-time status.

The process involves creat ing a “digital twin” (DT) of a system such as a substation or generator plant and using the information from the twin to monitor and manage the real system. The DT usually consists of a 3D image of the item, and contains information, both historical and real-time on each component of the system. Thus the characteristics and specifications of each item can be accessed as well as real-time performance information. The DT is also capable of combining performance data to show trends and variations over groups of components.

DT systems were first applied in the infrastructure construction industry, to manage the many components in complex structures, but has been extended to include dynamic performance details of power, water HVAC etc. The principle has been applied to large machines, by including large numbers of sensors in the machine and using these to generate the DT of the machine, which gives information on such things as temperature profiles, vibration etc., in real time, and is now being applied to distributed generation plant such as solar PV farms.

Digital twins are best created at the design phase, where information on every component, including expected performance, can be entered. DT has been applied on a limited scale in several large solar farms [6]. Ideally the DT should incorporate real-time performance data on every panel, but this would require several hundred thousand entries, and monitoring of the performance of every panel, so the existing models tend to focus on consolidated real-time data such as that available from inverter stations. Thermographic and other

Fig. 4: Digital twinning of solar plant (GE).


RENEWABLE ENERGY

panel specific status information, on the other hand, could be included on a panel by panel basis. DT could be used to provide a visual model of the entire plant, identifying areas of high temperatures, hot spots or areas of high soiling, physical damage, etc. Identifying areas with possible problems could make the physical location of such problems much easier.

Using a digital twin, the replica can inform when an asset begins to show signs of non-optimal performance, without having to access the physical asset. This could give an indication of when the asset could fail, minimising the risk of unexpected downtime. Gaining this insight into upcoming issues allows maintenance decisions to be made based actual data, as opposed to pre-defined maintenance schedules or guesswork. Assets can then be kept at their optimal level for maximal profits, rather than performing random, reactive maintenance when a part breaks down [5].

Digital twinning provides asset owners with enhanced real-time analysis and critical efficiency parameters, it also

prevents downtime by extending its application to predictive maintenance and efficiency optimisation. Predicting equipment failures and non-performance of assets using digital representation, can improve uptime and excessive physical repair costs, especially in cases where scheduled calendar maintenance and reactive repairs increase asset downtime.

Distributed generation technologies come with their own set of challenges. Managing the variability and intermittency of solar is important to improve asset performance and to keep the asset running at peak performance. Asset operators can optimise DR management by monitoring solar radiation and weather patterns, and forecasting demand-supply aggregation.

Solar projects are each made up of tens of thousands (even millions) of individual solar panels as well as other pieces of equipment. Each panel, if from a reputable manufacture, has its own performance specification, and this can captured at the construction stage. It is not considered to be useful to monitor the performance of individual panels, but this information can be used to create

an expected aggregate performance for a group of panels, which can be measured and monitored. DT allows a visual indication of the aggregate performance of groups of panels as well as the total installation. What is the twin of a solar project? Is it the entire plant,or the inverter “string” of hundreds of solar panels. The level of aggregation to which the DT needs to drill down, will depend on the system design and other factors, such as site specific variations. As processing becomes cheaper, as sensors become cheaper, as sensors become better, as data transmission becomes both, the level to which the digital solar twin can go will increase.

There are several solar sites where digital twinning is being piloted. Sites piloting DT at the moment tend not to go further than the inverter level, but plans are in place to drill down deeper into the systems, as experience is gained [6].

References

The references for this article can be found with the online version at https://wp.me/p5dDng-1afv


Company Projects Products Technology


RENEWABLE ENERGY NEWS

For testing PV modules and strings

HV Test, with Gossen MetraWatt, is proud to present the Profitest PVSun and PVSun Memo, allowing the user to conduct all required safety tests of photovoltaic systems, simply and safely. The instrument is suitable for testing PV Modules and strings up to 1000 V/20 A in accordance with DIN EN 62446 (VDE 0126-23). The unit is capable of insulation measurement, polarity testing, ground fault testing and protective conductor continuity testing.

Contact Liz da Silva, HV Test, Tel 011 782 10101, [email protected] v

High power wind turbines ordered

The French multinational c o m p a n y Q u a d r a n International has through its subsidiary Quadran Brasil, placed an order for the 206 MW Serrote wind park to be located at the municipality of Trairí, in the state of Ceará. The contract includes the supply and installation of 49, V150-4,2 MW wind turbines with a 125 m hub height. The power from Serrote wind park will be supplied to the Brazilian utility CEMIG through a PPA agreement with Quadran. Turbine delivery is expected to commence in 2020 and commissioning is planned for 2021. The order is Vestas’ first project in the state of Ceará, where the company ’s Brazi l ian V150-4,2 MW nacelles factory is located. Serrote wind park’s 49 nacelles as well as the wind park’s blades and towers will be locally produced under the Brazilian Development Bank’s rules.

Contact Andrés Domínguez, Vestas, [email protected] v

Cost-reduced drone-based wind turbine inspectionsSulzer & Schmid Laboratories has launched a new inspection platform, the 3DX HD, which has been developed as a cost-effective solution to cope with large volumes of high definition wind turbine blade inspections. Based on the compact and flexible DJI M-210 drone, the platform delivers fully autonomous drone inspections at a lower cost compared to its existing 3DXTM Ultra-HD product based on the DJI’s M-600 drone. Due to the new capabilities offered by UAVs, the market for drone-based rotor blade inspections has grown in recent years. The autonomous solution reduces human error, and is repeatable and consistent in quality while covering 100% of the blade. Most importantly, the digital end-to-end process creates a foundation for trend analysis and predictive maintenance. Whereas critical inspections, such as end-of-warranty or change of ownership, call for the high quality images such as those provided by the 3DXTM Ultra-HD product, regular inspections can now be carried out with great efficiency by the 3DXTM HD platform at a fraction of the cost. The platform is compact enough to be checked-in as regular luggage for air travel and can be deployed easily on CTV ships for offshore wind inspections.

Contact Sulzer & Schmid Laboratories, [email protected] v

Compact portable hygrometer for convenient spot checks

Instrotech is offering the Michell MDM50 portable hygrometer that quickly and simply takes spot checks of dew point or moisture content down to -50°C dew point. Because it has its own self-contained sampling system, setting up the MDM50 involves simply connecting the hose to the sample point: there are no extra sample conditioning add-ons to purchase or to carry around. The integral sampling system allows for measurements of dew point to be made at pressure, up to 20 barg, with an option available to measure up to 300 barg. The integrated filter removes particulates down to 0,3 μm which provides 99,5% protection to the sensor. The fast-responding polymer moisture sensor of the MDM50 gives rapid dew-point measurements in compressed air – T95 to -35°C from ambient typically in less than 5 minutes. The sensing element is highly stable, resistant to contamination and, along with the robust and sturdy case, this means the hygrometer is well-suited to the often tough conditions in industrial applications.

Contact Instrotech, Tel 010 595-1831, [email protected] v




Wireless DC current clamps improve measuring productivity

Comtest has Fluke’s a3003FC and a3004 FC wireless DC current clamps on offer. Both fully-functional current clamps can wirelessly send measurements to Fluke Connect enabled master units as well as the Fluke Connect mobile app so users can view measurements from multiple devices simultaneously, review equipment history, and share measurements with other team members for faster troubleshooting. Both current clamps can record and store up to 65 000 measurements with the logging feature to isolate intermittent events or record fluctuations without even being there. The clamps, along with more than 20 other Fluke tools, are part of the Fluke Connect system – the world’s largest portfolio of connected tools. It allows technicians to make better and faster decisions by having access to maintenance records wherever they are working. The Fluke Connect app can be downloaded for free from the Apple App Store and the Google Play Store.

Contact Comtest, Tel 010 595-1821, [email protected] v

Solar power overnight

Vast Solar has built a modular, grid-connected 6 MWth CSP plant with thermal energy storage, at Jemalong, New South Wales, Australia. The plant is designed to achieve high efficiency

at low cost. Each of its five, small array-modules concentrate solar radiation on a dedicated thermal receiver tower 27 m in height. The five modules connect to a central thermal energy storage tank, from which the stored thermal energy is passed through a steam generator to make steam for a 1,1 MWe turbine and electricity generator. The project’s thermal energy storage system can dispatch renewable energy – on-demand – day or night.

Contact Craig Wood, Vast Solar, [email protected] vSolar farm offsets tonnes of carbon emissions

One of the world’s largest solar power companies has announced that its first solar power project of 68 MWp in Mexico started commercial operations recently. The solar

plant, located in Aguascalientes, Mexico, is powered by over 200 000 Canadian Solar high-efficiency poly modules CS6U-P. The plant will generate 145 GWh of electricity annually, enough to power 20 690 households and offset 72 700 tonnes of carbon dioxide emission each year. In addition to that, a total of 535 jobs were created during the PV plant construction and more than 15 new jobs are expected to be created for operations and maintenance during the upcoming 20 years the plant is in operation. The company says it will provide operations and maintenance services to the plant.

Contact Mary Ma, Canadian Solar, [email protected] v



Fault passage indication is the use of a protection asset to flag whether a network parameter excursion (current, voltage, frequency or a combination thereof) was detected at a node in the distribution network. Typically, a pickup level is set, with a short hysteresis operating time, to set a flag for possible fault passage through a node.

Essentially, automatic circuit reclosers are used as protection devices in their own right, but they can be configured to provide alarms or FPI indication at more sensitive settings. This tandem protection configuration mitigates risk of spurious tripping but provides data granularity for fault location estimation.

Furthermore, when using the Noja Power OSM recloser as the fault passage indicating device, it is possible to use

Fault passage indication by means of distributed recloser assets

Information from Noja Power

Locating faults in the electricity distribution network can be a costly and time-consuming process. Network complexity and non-linearity provides additional challenges with using transmission-style fault location techniques. An improved technique for optimising the fault location process is to utilise distributed intelligent switchgear assets such as automatic circuit reclosers to flag fault passage throughout the network, allowing operators minimise patrol areas for locating faults.

directional protection as a fault passage indicator. This capability is essential in high impedance earth faults, allowing utilities to determine if the measure fault passage was a capacitive effect or a genuine downstream fault.

OSM reclosers have been used extensively as complementary fault passage indication devices. The reclosers are typically distributed throughout the entire grid, providing a global view of the network and the ability to segment fault zones very clearly. With the majority of new OSM Recloser installations including a form of remote communications, fault location becomes significantly less costly than traditional patrol methods.

Neil O’Sullivan, the company’s group managing director says the reclosers improve the instantaneous vision its

customers have over their networks. Fault passage indication is an important data point for fault finding locally or remotely and can even be built into automatic fault detection and isolation schemes.

For simple fault passage indication, standard protection elements in the OSM Recloser’s RC10 controller can be configured to alarm and latch at lower pickup levels, providing vision of fault passage. However, more sophisticated algorithms have been developed using OSM reclosers smart grid automation IEC 61499 protocol, providing protection engineers with the ability to build applications using the PLC-style event driven logic table to handle complex cases.

Contact John Dykes, Noja Power, [email protected] v

Fig. 1: Recloser installation.



An additional phase-shift has to be considered by the differential protection to fulfill the requirements for selectivity. With two-phase faults outside of the transformer, an additional phase shift will introduce a differential current in the non-faulty phase. The protection relay has to handle this and be verified during commissioning. Relay manufacturers use different approaches as to how their relays ensure stability for phase-shifting transformers. Depending on the actual phase-shift, which is usually signalled to the relay using binary inputs, the differential protection has to adapt.

Principle of phase-shifting transformers

The pr inc ip le o f phase - sh i f t ing transformers is based on the introduction of a variable phase-shift for the purpose of controlling the real power flow over a specific network path. In the US phase-shifting transformers are mostly called phase angle regulating (PAR) transformers, whereas in UK they are known as quadrature boosters. Within this article we stick with the term phase-shifting. The variable phase-shift is usually achieved by introducing voltage components shifted by 90° (hence the name quadrature) from a delta connected winding, whereas the magnitude is varied using different moveable taps.

Using the shunt transformer in delta connection, voltage components shifted by 90° with respect to each phase are achieved. The output of the shunt transformer is then added to the phase voltages using a series transformer, which creates the vectorial sum of the phase voltage and the smaller 90° components. The tap connections on the shunt transformer allow the control of the magnitudes of the 90° components and therefore the magnitude of the phase-shift. Phase-shifts both in positive and negative directions are possible. The two transformer units are usually built as separate units in their separate tanks. But there are other constructions, where all the windings are on the same core

Using differential protection for phase-shifting transformersby T Hensler and F Fink, Omicron Electronics; and H Mitter, Vorarlberger Energienetze

Due to the increasing demand to control power flow within our networks, more phase-shifting transformers (quadrature boosters) are being installed. The most important protection principle for transformers is differential protection.

(single-core), so that a single tank is more economical.

Another common technical solution is the integration of a phase-shifting transformer into a power transformer for transforming from one voltage level to another. Power transformers between different voltage levels usually have multiple taps with slightly different turns-ratios for voltage regulation already. Then additional taps for the phase-shifting are built into the same transformer too. Since taps for voltage regulation can be available either on the high voltage or low voltage side the phase-shifting taps are then mostly realized on the opposite side of the voltage regulating taps.

For example, a 410 kV:230 kV YNy0 transformer which has a conventional voltage regulation tap changer on the high voltage side with 17 taps. On the low voltage side there are 35 taps with phase shifts from -17,22° to +17,22°. The polarity of the phase shift is switched with a separate switch, usually called advance/retard switch, before the taps are wired to the online tap changer (OLTC).

This transformer is built into two separate tanks, as is indicated by the dashed lines

surrounding the separate units. The regulating transformer is just connected on the lower end of the low voltage wye winding and there is the delta winding from the main transformer tank to create the 90° phase-shifted voltages. This allows for a more economical construction of the regulating unit. For each phase a small voltage part from both of the two other phases in equal magnitude is added to the main phase voltage, so that a component with 90° is added finally.

Challenges for differential protection

The main protection principle for power transformers is differential protection (ANSI 87T). Differential protection elements supervise the differential current between high voltage and low voltage side and trip as soon as the differential value exceeds a certain threshold. To stabilize the protection, a percentage restraint characteristic is used, where a restraint quantity (bias current) is used, which usually reflects the magnitude of the currents through the transformer. Using a percentage restraint characteristic, the differential current threshold can be controlled depending on the bias current.

Fig. 1: Principle of a phase-shifting transformer.



For higher bias current a higher threshold is necessary.

Restraining the differential element with a bias current is used to achieve stability for a lot of different circumstances during transformer operation, such as CT errors or CT saturation. Additionally, the percentage restraint characteristic can compensate for small differences in the calculated differential currents due to voltage regulating taps of the transformer. Although there are some protection relays, which take the current tap position into account and adjust the turns ratio accordingly. For the calculation of the restraint quantity (bias current) the different relay manufacturers use quite different approaches and formulae.

There are protection relays, which determine the bias current individually for every single phase, whereas other relays choose a maximum value among all the phases to get good stability for all different vector groups. For a transformer with taps for phase-shifting the influence of the phase-shift in both angle and magnitude cannot be compensated for with a higher percentage restraint characteristic anymore. Phase shifts up to 20° and more result in a current transformation behaviour, which is almost similar to a different vector group.

So, for protection of phase-shifting transformers the differential relays have to adapt its behaviour according to the current tap position to achieve consistent stability for all different operating states of the transformer. A special challenge for the differential protection arises for 2-phase faults outside of the protected transformer. The phase-shift achieved within the transformer is effective for the positive sequence components as specified. But for the negative sequence currents the phase angle is applied into the opposite direction. This will cause an unsymmetrical distribution of the currents through the transformer for 2-phase faults, where negative sequence currents are present, and will introduce a considerable differential current in the non-faulty phase too.

Differential protection for phase-shifting transformers

Differential protection for phase-shifting transformers has to take into account the phase-shift of the currents for accurate calculation of differential currents. Older standard transformer differential relays were not designed to cope with these specific requirements. Nevertheless, for the protection of phase-shifting transformers protection devices designed for conventional transformer protection can be used if an artificial third winding is

used to mimic the phase-shifted currents. This is a quite often used approach and has been documented by the various manufacturers in application notes for their relays. New generations of transformer differential relays are already designed to support phase-shifting transformers and can model the specific behaviour of the transformer within the relay algorithm in firmware.

Example at a utility in Austria

A transformer differential relay for a 3-winding transformer from Schneider Electric has been used. Current inputs for the high voltage side are wired as usual into input A. For the LV side the secondary currents from the CT are first wired to the input B and then in series through the input C for the third winding of the 3-winding relay. Within the relay different setting groups are used, which parameterise the third winding in such a way, that the phase-shifted components are considered by the differential element according to the current phase-shift of the protected transformer. For positive phase-shifts a vector group of Yy0y8 is used, for negative phase-shifts Yy0y4.

The CT turns ratio setting in the relay for the third winding are set in such a way, that the resulting magnitude is about the same as the 90° component introduced by the phase-shifting transformer. Using binary input contacts from the tap changer, which controls the phase-shift taps on the LV-side, the relay is switched between the different setting groups instantaneously. It is important that the relay supports a setting group

change during normal operation of the protection and does not require a reboot of the firmware or introduce another delay for the protection functions during setting group changing. For this specific application it was sufficient to use three setting groups, For the tap in neutral position +/- on tap position setting group 1 was used, which did not use the virtual third winding at all. For all tap position from number 1 to 7 with phase-shifts in positive direction setting group 2 was used and for all taps from 11 to 17 with negative phase-shifts setting group 3.

This was sufficient to fulfil the stability requirements under all different tap positions both for the voltage regulating taps on the HV side combined with any tap position of the phase-shifting side on the LV-side. The setting groups were changed using binary inputs from the tap positions.

Commissioning and testing of protection relays for phase-shifting transformers

Since all the solutions for protection of phase-shifting transformer involve either complex customised logic in the relays or elaborate detailed settings a comprehensive commissioning and testing is necessary before the protection is put into operation. It has to be verified, that for all tap positions the relay behaves as designed and that the requirements regarding stability and selectivity are met. A utility in Austria did commission a phase-shifting transformer with a primary short-circuit test on the transformer.

Fig. 2: Example of a 400 MVA quadrature booster (Wikipedia).



Therefore, primary injection was done using a mobile diesel generator set and distribution transformers 20 kV:400 V. They did inject on the 200 kV-side of the transformer and made a short-circuit on the secondary 110 kV side. The short-circuit current was applied with 100A which resulted in a voltage of 3,3 kV.

Tests were done for 3-pole, 2-pole and single-pole outside faults. The resulting currents were applied to the protection relay and the IDiff and IBias values were retrieved from the protection device connected. Within the percentage restraint characteristic, the values were scaled up according to the nominal short-circuit voltage of the transformer, which correspond to realistic infeed conditions during normal operation. For all the tests done it could be shown that the protection was stable for outside fault using the protection principle with the virtual third winding. For secondary testing a model of the transformer to calculate its current distribution was developed based on a mathematical model of the transformer in an Excel spreadsheet.

Using these values protection testing with injection of steady-state values according to the calculated values were possible, which did show the same results as the

primary tests done. The most convenient tests are possible using a new protection testing software, which is capable to simulate the transient behaviour of a phase-shifting transformer. Within this software the transformer with all its taps both on the HV- and LV-side is modelled. Then different scenarios with steady-state and dynamic faults can be simulated easily, whereas the resulting transient current signals can be injected to the protection relay using a conventional protection testing device.

Summary

Transformer differential relays for phase-shifting transformers have to consider the tap position of the voltage and phase-shifting tap changer into account to be able to calculate correct IDiff and IBias quantities. A common approach used with conventional transformer differential protection relays is to use a virtual third winding with currents from the CTs in series to the LV-winding. Using this approach, it is possible to simulate the 90° current component using logic elements of the relay or a corresponding vector group within the protection device. Using binary inputs from the tap changer the relay logic can adapt or switch between different setting groups

in the relay accordingly. With the newest generation of transformer differential relays, it is already possible to model the detailed behaviour of voltage and phase-shifting taps within the firmware of the relay.

For commissioning of differential relays on phase-shifting transformer, it is necessary to verify the correct behaviour of the protection for the different tap positions of the phase-shifter. For the critical case with a 2-phase outside fault, which will cause an additional differential current in the non-faulty phase, there should not be any false trips. Using a new simulation-based protection testing software, which can simulate a phase-shifting transformer with all its voltage and phase-shifting taps, a convenient way to test and commission such protection relays is possible. A manual calculation of the test quantities, which is complicated and error pone, is no longer necessary.

References

The references for this article can be found with the online version athttps://wp.me/p5dDng-1amH

Contact Alexander Dierks, Alectrix, Tel 021 790-1665, [email protected] v

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www.zestweg.comTel: 0861 009378

Power & Distribution Transformers

Power & Distribution

ZWG_general_130mmx180mm.indd 1 2018/12/04 10:28



Global demand and product ion capacities increase simultaneously. This calls for higher voltages and currents from powerful transformers to accommodate the most challenging demands and severe working conditions. The transformers are exposed to cyclical loading and high thermal stress. They must withstand frequent overcurrent and overvoltage caused by short circuits in the furnace or tripped by high-voltage circuit breakers. As high currents cause enormous electromagnetic fields, special attention must be paid to prevent transformer overheating and system malfunctions.

An outage can cause a total loss of industrial production, such as when pots or furnaces “freeze.” The outage costs can quickly put even large facilities in financial difficulties. Every single transformer must be precisely tailored to meet individual demands. Low-cost standard solutions can later become very costly for the industrial customer.

Producing 80 tonnes of steel requires more than 35 000 kWh of power and 44 000 A. It takes 50 minutes to charge, melt, refine, de-slag, and tap each batch

Powering the steel industryInformation from Siemens

Both metallurgical and other industrial plant processes, as well as large drive procedures depend on reliable, highly specialised transformers. In steel plants, for example, it is crucial to supply high currents for AC and DC electric as well as ladle furnaces. Electrolysis processes operate with heavy-duty rectifiers which are fed by rectifier transformers. Large drive mining applications and variable speed drives depend on converter transformers to supply power to blast furnaces, pump stations, or rolling stock

of steel. Following each cycle, it should take 60 minutes or less to repeat the process, tap-to-tap.

Melting processes require enormous currents and have extraordinarily severe working conditions. They work under high operation currents that are often close to their short-circuit values. At the same time, melting processes face frequent on- and off-switching and tap changes during operation. But, despite being stressed to their limits, an unplanned outage of a furnace transformer has an enormous financial impact and should be prevented at all costs. This calls for extremely robust and reliable transformers.

When designing a power transformer, it is important to consider the options:

l Direct or indirect regulation or booster.

l On-load or off-load tap changer (ONTC or OLTC).

l Oil or vacuum type OLTC (also reactor type OLTC).

l Series reactor (built-in or separate) for long arc stability.

l Air or water-cooled secondary bushing arrangements and designs.

l Internal secondary phase closure (internal closed delta).

l Special magnetic shield design for each project.

l Oil-forced (OF)- or oil-directed (OD)-cooling.

Combining with a series reactor is recommended for improved efficiency and clear and stable reactance, either as a stand-alone unit or incorporated into the tank of the electric arc furnace (EAF) transformer.

Measures against impermissible heating

Heating due to winding currents

The currents in the windings cause losses (load losses), which need to be dissipated by the cooling device. A standard of many manufacturers is OFWF (oil forced, water forced) cooling. The pumps of this system circulate the oil between transformer tank and cooling device. The oil flow through the winding stays comparable with ON (oil natural) -cooling. It’s naturally driven by thermal convection. According to IEC the average winding temperature rise at OD-cooling may be 5°K higher than it can be with OF-cooling.

Heating due to high magnetic fields of current carrying parts

The LV connection and the LV bushings are the transformer components with the highest currents. Each current causes a magnetic field, and high currents cause correspondingly large magnetic fields. Magnetic fields cause eddy currents in ferromagnetic materials like transformer tank or cover and also in plant structures. Eddy currents cause additional losses and heating.

Siemens designs have partly unique features to avoid impermissible heating due to high magnetic fields. One of these is the use of non-magnetic steel at structures which are close to current carrying parts. The LV side and partly Fig. 1: Oil-forced water-cooled (OWF) transformer cooling process.



the side walls of the transformer tank should be made of non-magnetic steel. Also, distances to the cover should be checked and if necessary, the cover should be made of non-magnetic steel at least partly on the LV side. The press beams of the active part supports of the LV connection and bolts of insulation screw connections are also made of non-magnetic steel. Screw connections with magnetic material can cause gassing.

Significant for the usage of non-magnetic steel is also the LV connection in the plant outside the transformer. This will be considered during the design process and, if desired, Siemens can check the structure in the transformer cell to give a recommendation for shielding in the plant.

Many manufacturers use fibreglass reinforced plastic as a material for the LV bushing plate. The bushing plate of Siemens furnace transformers is made of aluminium. The large aluminium plate shields the environment against the magnetic fields of the transformer and the transformer against the magnetic fields of the LV connection in the plant. Fig. 3 shows (A) the defined shield grounding; (B) the aluminium shield at the bottom of the tank to protect against high magnetic fields; (C) the oil channel at the press beam which leads oil for the OD-cooling. None of the Siemens tank part designs need additional cooling.

Transformer insulation concept for defined grounding

The insulation concept of Siemens furnace transformers is defined from the core to the bushing plate. The concept decreases and avoids loop currents, which can be the reason for hot spots at the transformer and the structure in the plant. The core and the press beams are insulated separately from each other. Core and press beam earth are brought out separately to a terminal box on the cover or at a side wall of the tank.

The insulat ion resistances of al l components have to pass a quality check during the manufacturing and are recorded. All components have defined earth points and can be grounded in a defined way.

Electrical contacts of furnace transformers are under special stress due to the high currents and short circuit forces. High currents can cause the accelerated aging of electrical contacts. Deficient electrical contacts can cause failures of transformers due to gassing or total failure of a contact. The standard of

many manufacturers is the usage of screw or press contacts in furnace transformers. According to Siemens design rules the usage of screw or press contacts is not allowed for high current contacts. Siemens uses only brazed or welded contacts. It is also possible to braze all contacts of the transformer. Only two exceptions are allowed: The screw contacts of the MR OLTCs (On-load tap-changers by Maschinenfabrik Reinhausen) and the screw contacts of the U-tube bushings.

Conclusion

Melting processes are dependent on reliable power supply, yet they represent severe working conditions and require enormous currents. For the steel industry, it is of crucial importance to prevent an unplanned outage. This is why no compromises on the design and quality of furnace transformers should be made.

Contact Jennifer Naidoo, Siemens, Tel 011 652-2795, [email protected] v

Fig. 2: Typical furnace transformer for the steel industry.

Fig. 3: Aluminium shields inside the tank.

TRANSMISSION AND DISTRIBUTION NEWS



Fast track solution irons out fluctuating voltage

When a Gauteng-based pharmaceutical manufacturing facility decided to upgrade its electrical systems, it discovered severe voltage fluctuations which could reduce the life and performance of its equipment. Trafo Power Solutions solved this potential headache with an innovative and fast-tracked installation. The pharmaceutical company had decided to relocate its factory’s substation and to switch to a dry-type transformer due to its high level of safety and low environmental risk. The absence of oil in the cooling systems of these cast-resin transformers means that they are safe enough to be installed indoors and pose minimal environmental hazard as there is no chance of oil-spills. Although there was significant time pressure on the delivery and installation, the company was able to ensure that the transformers and tap-changers were sourced, commissioned and handed over within ten weeks of the purchase order being presented.

Contact Trafo Power Solutions, Tel 011 325-4007, [email protected] v

Pinpointing cable faults with thermal imaging

The consequences of a cable break for heavy industries are costly both in terms of lost productivity and downtime. So, for the German cable repair specialist Becker and Hüser, its focus is to get its customers back in business in the shortest amount of time and Flir thermal imaging is playing a vital role in helping to pinpoint the exact location of the problem. Repairing a cable is often the most time efficient option if a replacement is not held in stock, as waiting for the supply of a new cable can sometimes take months. The company can repair a cable in a matter of days and sometimes even hours. The process involves the connection of an enormous tangle of fibres which is both a meticulous and time-consuming task.

Contact Reynard Heymens, Flir Systems, Tel 011 300-5622, [email protected] v

Addition to thermal camera seriesFLIR Systems has launched the FLIR T840, a new thermal camera in the high-performance T-Series family. The high-resolution T840 offers a brighter display and an integrated viewfinder to help electrical utilities, plant managers and other thermography professionals find and diagnose failing components in any lighting conditions to help avoid power outages and plant shutdowns. Featuring the award-winning design of the FLIR T-series camera platform, the T840 features an ergonomic body, vibrant LCD touchscreen, and a viewfinder. The 464 x 348 resolution camera incorporates FLIR advanced vision processing, including patented MSX image enhancement technology, UltraMax and proprietary adaptive filtering algorithms to provide custom ers with enhanced measurement accuracy and image clarity with half the image noise of previous models. The T840 also offers an optional six-degree lens allowing professionals to capture accurate temperature measurements on small targets at far distances.

Contact Reynhard Heymans, Flir Systems, Tel 011 300-5622, [email protected] v

Lenses for infrared cameras

Infrared inspections often involve analysing temperature variations on something extremely small or too far away to see the needed detail with standard lenses. Two lenses for Fluke infrared cameras bring those worlds into sharper focus. The 25 micron macro lens can identify defects that might otherwise be too small to see on targets like PCB boards. The 4x telephoto lens gets users a four times magnified view of a target at a distance, so targets like a high electrical line or a tall flare stack can be easily inspected. The two lenses expand the Fluke portfolio of lenses for select infrared cameras of 320 x 240 resolution and under. The Fluke portfolio of lenses now includes standard, wide angle, macro, and 2x and 4x telephoto lenses – all precisely engineered germanium optics. All these lenses are easily exchanged between compatible cameras without the need to send the lens and camera back to the factory for calibration, eliminating the cost and downtime caused by shipping and additional calibration.


Company Projects Products Technology TRANSMISSION AND DISTRIBUTION NEWS


CEO looks to grow African footprint

As part of its ongoing growth plans, Zest WEG Group will continue to focus on opportunities in more African countries, according to Siegfried Kreutzfeld, its new chief executive officer. With 40 years of service in the global WEG Group,

Kreutzfeld brings a wealth of industry experience to the top job at the South African business, which he joined in January 2019. He was most recently the managing director of WEG China. Established in South Africa to create a strong national footprint, the Zest WEG Group has grown steadily into other Africa countries. With its responsibility for the sub-Saharan market, it operates branches in Ghana, Tanzania, Mozambique and Namibia.

Contact Zest Weg Group, Tel 011 723-6000, [email protected] v

Earth fault algorithm for recloser controller

Noja Power has released an upgrade to its recloser controller firmware and introduced an optional Cos Phi algorithm to the existing earth fault protection suite. Although the OSM recloser system with RC control already possesses a high resolution SEF capability, with pickup from 200 mA SEF, the inclusion of the Cos Phi algorithm provides greater precision in compensated neutral networks with respect to directional protection. The Cos Phi earth fault algorithm in the recloser’s controller provides protection engineers with the capability to achieve improved performance goals. The Cos Phi algorithm implementation is further enhanced by an upgrade in selecting operating ranges for relay characteristic angles in directional protection. Improving the accuracy of the operating range for a directional relay allows protection engineers to mitigate the risk of spurious tripping of SEF under high impedance fault conditions.

Contact John Dykes, Noja Power, [email protected] v


Today, with more and more users relying on own-generation plant, be it to save costs or to provide security of supply, cogeneration is moving more towards the state where electricity production becomes an important factor, although the production of process steam is still the primary purpose. This changes the structure from a system where the amount of electricity generated was dependant on the surplus heat available, to one where electricity production forms a large part of the total production and there needs to be a careful balance between power and heat production.

Typical examples would be sugar mills, where bagasse left over from cane crushing is used to generate steam which conventionally powers a steam turbine generator and produces heat for the sugar production process. The electricity produced is often more than what is required in the mill, and is usually fed into the grid. This surplus electricity is

Developments in co-generation in sugar mills

by Mike Rycroft, EE Publishers

Cogeneration is normally defined as the generation of electricity and heat from the same energy source. The term is often applied to systems that use waste material from an industrial process to generate steam, which is used to generate electricity and process heat for the industrial process itself. Traditionally biomass based cogeneration plant has worked on direct combustion steam boilers, but new developments have shown that the biomass gasification cycle can provide a much higher efficiency, produce more electricity, and produce higher quality process steam.

an important asset as it can be sold to the utility.

In addition electricity costs and tariff hikes are making it profitable for sugar mills to generate surplus electricity from biomass such as bagasse and supply to the grid. In most sugar producing operations the bagasse produced exceeds what is required for both sugar production and mill electricity demand, and could be used to produce carbon neutral electricity for sale to the grid. Exploiting this reserve is hampered by the following factors:

l Production of electricity using low pressure boilers and backpressure turbines is inefficient.

l Only baggase is used for electricity production, whereas “sugar trash” comprising cane tops and leaves, which could be combusted, is left in the fields. It is estimated that sugar trash could increase the combustible biomass by between 50 and 100%.

l Production of electricity is often limited to the milling season by the fact that no steam is required out of season and backpressure turbines require process steam to operate.

Almost all the sugar mills are self-sufficient in terms of energy supply and many of them have been selling their surplus electricity to the grid for many years. The introduction of steam plants operating at higher pressure and temperature levels and biomass gasification systems operating in combined cycles, are new alternatives for increasing the efficiency of these systems, and increasing the amount of electricity for export. The optimisation of the energy process of sugarcane mills has been the subject of numerous studies. Traditional Rankine steam cycles are still being improved, but attention is mainly focused on advanced cogeneration systems, such as biomass integrated gasification combined cycle (BIG-CC) supercritical steam cycles, which may yield higher electrical energy surplus. Although the BIG-CC seems to be the best solution, the technology does not appear to be sufficiently developed for commercial scale operation , and supercritical Rankine steam cycles seem to be the following step for the evolution of sugar mills.

In many mills the bagasse production is more than that required for the daily energy requirements of the mill, and excess can be stored for electricity production in the off season. This is only possible with a steam cycle where steam production can be separated from the process steam usage cycle. The inclusion of sugar trash in the harvest makes a tremendous difference to the amount of electricity that can be generated.

Metrics

Before going into details it will be useful to look at some of the metrics used in the co-generation industry.Fig. 1: Sugar process steam requirements ([2]).

GENERATION


Power to heat ratio (P/H)

This is the ratio of the electric energy produced to the thermal energy produced in equivalent units by the system. It is useful indication of the system balance. Typical values are shown in Table 1. The P/H ratio is an important measure of the ability of the system to generate sufficient electricity to provide for the needs of the plant. If the ratio is too low, grid energy must be used to make up the deficit. This is important in sugar mills where the grid supply is often unreliable and expensive. The P/H ratio in older sugar mills is typically low, of the order of 0,15 to 0,3, meaning that electricity is generated from “surplus” steam and the main use of steam is for the sugar process.

The power to heat ratio depends on the amount of electricity generated per ton of fuel and is affected by several factors:

l The temperature and pressure of the steam supplied.

l The type of steam power generation plant used.

l The process steam demand.

Fuel efficiency (consumption)

This is a measure of the electric or thermal power produced per unit weight of fuel, and is usually expressed in kWh/t and BTHu/t or tonnes of steam/tonne of fuel combusted.

Process steam requirements

The original purpose of steam generation was to provide mechanical power and heat to the mill, and it will be useful to take a look at these requirements before considering power generation options. Fig.1 shows the mill processes and their steam requirements.

Mechanical steam turbines are used to drive large machinery such as that used in the juice extraction process. These use steam at a pressure of 15 to 20 bar and temperature.

Evaporators and crystalisers: These use steam at a pressure 1,47 to 2 Bar.

In-house consumption will depend on the degree to which electric drives are used in the mill. Many of the larger drives such as crushers, are steam driven, even in modern mills.

Developments in co-generation in the sugar industry

The average electrical energy output in the South African industry per ton of sugar cane crushed is approximately 30 kWh [1]. Figures from other countries range from 30 to 40 kWh/t, depending on the technology used. A good example of

how cogeneration is advancing is that advances have led to the electricity generation moving from 17 kWh/t of baggasse to 130 kWh/t or more with the same amount of process steam being generated [1].

Traditional systems

The first co-generation systems consisted of a low pressure baggase fired boiler, producing steam at around 350°C and 20 bar. Much of the machinery, such as crushers, were driven by steam turbines. There are still mills operating on this principle today.

The early sugar mills generated steam primarily for sugar production and the generation of electricity was added to take advantage of the surplus energy available. This resulted in the use of low to medium pressure boilers and back-pressure turbines. The energy balance of such a system is given in Table 2 [5].

Steam cycles – back pressure turbines

The back pressure steam cycle is widely used in sugar mills. This uses a back pressure turbine (BPT) to generate electricity and the output of the turbine is fed to the process steam line (Fig. 2). In this case the sugar process determines the quantity of steam that is produced by the boiler, as there is not a steam condensation system. Condensate from the steam using process plant is fed back to the water tank. The disadvantage of this system is that power generation will depend entirely on the process steam load, and will vary as the load varies. The pressure drop across the turbine is also limited, as the exhaust steam must be at the pressure required for the process stages. This kind of cogeneration system is the most common in older cane factories and can operate only during the crushing season when the factory

Fig. 2: Sugar mill low pressure boiler and back pressure turbine.

Fig. 3: Condenser extraction heat cycle [2].

GENERATION


is in operation and the steam demand exists. Back pressure turbines are simple in design, and occupy less space than other types, and also have a lower cost, both capital and maintenance.

Steam cycles – Condenser extraction turbines (CEST)

In the CEST system, exhaust steam from the turbine is fed to a condenser system and hence to the boiler. Process steam is extracted from the turbine stages, at the pressure determined by the process requirements (Fig.3). The amount of steam flowing through the turbine is much less dependent on the process steam requirements and electricity generation is more stable. The amount of steam supplied to the turbine changes as the amount of steam extracted from the turbine varies, to ensure a constant flow of steam through the turbine.

Condensing and extraction steam turbines allow processing of all the possible feedstock. The electrical output is maximized because it permits the expansion of steam until the minimum pressure is reached in the condenser. Following this route, a more constant electrical energy surplus can be produced. Actual boilers and turbines are operated in the pressure range from 15 to 105 bar, corresponding to a temperature range of 300 to 525°C [3].

High pressure boilers

It has been shown that using high pressure boilers can improve the efficiency of steam usage [2]. Higher pressure steam requires higher fuel consumption, but this is offset by increased efficiency and increased electricity production. Typical values for high pressure steam boilers would be 80 to 100 bar. and 480 to 510°C. Advanced cogeneration systems in the form of high pressure direct combustion steam rankine cycle (SRC) systems and biomass integrated gasification combined cycle (BIG-CC) systems have the potential to significantly increase the electricity generation capacity of sugar factories. For efficient cogeneration, sugar mills generally adopt the path of installing higher pressure boilers and CESTs. In a few cases, factories have used boilers that operate at 100 bar. This combination of high pressure boiler and CESTs (Fig. 2) is capable of generating much more surplus electricity for export to the electric grid, as higher pressure steam (which is also higher temperature) can produce more work than lower pressure steam.

However, high pressure systems, especially over 60 bar, require special construction

techniques and materials that withstand the high pressure and associated high temperatures (over 450°C) [2]. CESTs also require a condenser system with a cooling tower and pump. These additional capital and operating costs need to be considered to determine the actual net revenues from surplus electricity generation.

Although high pressure boilers are usually combined with CESTs, they are also be used with BPTs. In this system, using the back pressure turbine, the pressure and temperature drop across the BPT are significant, and the electricity generation increases significantly. Usually, pressure reducing valves would be used to control the high pressure steam used in the process. The BPT effectively acts as a pressure reducing valve, but generates energy in the process, energy which would be lost if a PRV was used. A similar argument applies in the case of CEST cycle. An example of the increase possible is given in Table 2 [2, 5].

Biomass integrated gasification combine cycle systems (BIG-CC)

Biomass gas i f icat ion has found application in large power station generation, but the potential for use in

co-generation plant, especially sugar mills sugar mills has only recently been considered The use of BIG-CC plant in sugar mills has been extensively researched but there are no known working installations to date.

BIG-CC technology may have the potential to generate electricity more efficiently than a conventional SRC system,while being cost competitive at the same time. Biomass thermal gasification is the incomplete combustion or partial oxidation of biomass that results in the production of combustible gases consisting mainly of carbon monoxide and hydrogen. The goal of the gasification process is to maximise the solid fuel carbon conversion as well as the heating value of the product gas.

The partial oxidation can be carried out using air, oxygen, steam or a combination of these. Most large scale gasification systems for electric generation use air and/or steam gasification. Air gasification produces a low heating value gas (4 to 5 MJ/Nm3) due to a high concentration of nitrogen [2].

In a BIGCC system (Fig. 4), the product gas from the gasifier after being cleaned and filtered, is fed into a gas turbine to

Source of energy Value

Bagasse per tonne of cane crushed (kg/tc) 200 to 300

Steam production per tonne of bagasse (t/t) 2,14

Steam/tonne of cane crushed (kg) 428 to 670

Steam required for sugar process (kg/tc) 300 to 450

Surplus steam potential for generation(kg/tc) 120 to 370

Table 1: Energy production example.

Fig. 4: BIG-CC steam cycle.

GENERATION


run an electric generator. The surplus heat in the exhaust gases from the gas turbine is used to generate steam in a heat recovery steam generator (HRSG) and run a bottoming steam Rankine cycle for additional electricity generation. In the case of sugar factories, some steam can be extracted from the CEST for the processing needs of sugar and/or ethanol. The exhaust flue gases from the HRSG can be used in a bagasse dryer to extract waste heat. It is generally essential to reduce the moisture content of bagasse to <20% depending on the type of gasifier used [2].

The layout of a typical BIG-CC plant is shown in Fig. 4.

The advantage of this system is that steam can be generated at the temperature and pressure for each requirement separately. This allows steam production to be optimised for each process independent of the others, and makes the use of backpressure turbines and CEST turbines unnecessary. This also allows the turbine

to be optimised for power production for process steam production. This does not however exclude the use of BP and CEST turbines.

Several types of gasifier designs exist depending on the scale, fuel, fuel size and other parameters. Circulating fluidized bed (CFB) is one of the more suitable technologies for use with bagasse in a BIGCC system, especially for gasifiers with fuel capacities greater than 10 MW thermal. In general, the biomass particle size of bagasse (<50 mm) allows for higher efficiency conversion in fluidised bed gasifiers due to better mixing with the bed material and greater carbon conversion rates [2]. CFBs allow for more complete carbon conversion and permit higher specific throughputs than bubbling bed.

Several possible configurations have been suggested including

l Independent power and process steam generation: This mode uses

a separate bagasse steam boiler for process steam generation and the BIGCC system operates in full combined cycle mode. Electricity is still provided to the mill.

l Full or partial co-generation: As shown in Fig. 4.

BIG-CC is a relatively new technology and is in its development stage. Large scale BIG-CC systems have been installed only as demonstration projects. Although preliminary studies and pilot scale projects have been initiated to study the possibility of integrating a BIGCC system into a sugar factory, no known large scale bagasse based BIG-CC system has been installed and operated at any sugar mill.

Development path

Refinement of the direct combustion cogeneration system can yield electricity generation rates of 120 kWh per tonne of cane, compared to typical factory performance of about 10 to 20 kWh/t of cane (tc) worldwide [3]. According to some estimates, BIG-CC technologies under development are projected to attain even higher overall efficiencies, yielding electricity generation rates greater than 200 kWh/tc [3]. Comparison of the possible upgrade stages is shown in Fig. 5 [2].

Advantages of increased electricity production in sugar mills

The sale of electricity to the grid is not the only reason for upgrading electricity production. Increased electricity allows replacement of steam turbine driven machinery such as crushers and other drives in sugar mills, with electric motor drives. This reduces the mechanical steam load and allows even more steam to be used for electricity production as well as improving energy efficiency. Energy savings of up to 40% have been reported where the crusher drive was changed from steam drive to electric drive. Steam turbines are less efficient, compared to electric motor drive systems. This is especially true when heat losses from the steam are considered. On the other hand, electric variable speed drives have efficiencies over 95%, keeping processes operating at optimal levels and maximizing profitability.

References

The references for this article can be found with the online version at https://wp.me/p5dDng-1ahK


Table 2a: Electricity surplus in some Brazilian and Indian sugar milling plants ([3]).

Country Steam system configuration Surplus electricity (kWh/tc)

Brazil BPST 22 bar 300°C 0 to 10

Brazil BPST 42 bar 440°C 20

Brazil BPST 67 bar 480°C 40 to 60

Brazil CEST 65 bar 480°C 140

Brazil CEST 105 bar 525°C 158

India CEST 67 bar 495°C 90 to 120

India CEST 87 bar 515°C 130 to 140

Steam pressure/temperature

Tonne steam/tonne bagasse Tonne steam/MWh MWh/100 t bagasse

18 bar/360°C 2,42 9,12 24,0

31 bar/410°C 2,14 7,22 29,6

45 bar/445°C 2,09 6,29 33,3

Table 2b: Gains possible by using high pressure boilers ([2]).

Fig. 5: Increase in surplus electricity generation by upgrading of mill steam system [2].


There is an explanation for every oil analysis result obtained, but that explanation is not always apparent and requires the abilities of a very special kind of pathologist – a mechanical pathologist also known as a diagnostician. In this article, we will take you on a journey through the eyes of a mechanical pathologist tasked with identifying the modus operandi of some of the most lethal engine oil contaminants known to cause premature or even sudden engine failure.

One of the main functions of oil analysis is to monitor levels of contaminants in the lubricating oil. Contaminants can be classed as being either internal or external. Internal contaminants are generated within the mechanical system such as wear debris or combustion by-products that accumulate in engine oils as a result of burning diesel. External contaminants are substances that exist in the environment that should not be in the oil, like airborne dust or water contamination.

Contaminants can be directly damaging to the mechanical system that is being lubricated. For example, dust is abrasive and can cause components to wear abnormally, but contaminants can also be indirectly damaging as they can cause the lubricating oil to degrade, which in turn may have an adverse effect on a mechanical system being lubricated.

When it comes to the analysis of used engine oils for condition monitoring purposes, certain contaminants are vitally important to monitor as they are often the root causes of premature oil degradation and engine failure. After lengthy interrogations with several suspected engine oil contaminants we have compiled forensic profiles on what we believe to be the most brutal killers known to the diesel engine.

The volatile killer

Let us begin our journey into the mechanically macabre with our first engine killer: fuel dilution. This engine

Beware these engine killersby Steven Lara-Lee Lumley, WearCheck

Engines don’t just simply die, they are murdered. A rather dramatic sentiment, I know, but then we take the death of an engine quite seriously at Wear Check. When reviewing oil analysis data, a forensic approach is required which incorporates a combination of science, experience and gut instinct.

killer was responsible for 21% of all engine-related problems we detected in the last year. When unburned fuel leaks directly into the sump, the problems caused are twofold – there is a physical and a chemical effect. Let’s examine these modes of attack in more detail.

Physical effect

The kinematic viscosity of a fluid is defined as a fluid’s resistance to flow under the force of gravity at a particular temperature. Viscosity is considered one of the most important physical properties of a lubricating oil as it determines the thickness of the oil film that prevents contact between metal surfaces. For a

Fig. 1: Fuel dilution vs. viscosity.

mental comparison think of water as having a low viscosity (flows easily) and honey as having a high viscosity (does not flow as easily).

The typical kinematic viscosity of diesel is between 2 to 5 cSt @ 40°C (think water) and the typical viscosity of a common diesel engine oil, say a SAE 15w/40 is about 100 cSt at 40°C (think honey) so as a result of this difference in viscosities between diesel and engine oil, only a small amount of fuel is required to significantly reduce the viscosity of the engine oil.

Moderate (±4%) to large (±8%) amounts of fuel dilution can drop the viscosity of

Fig. 2: Dust particle blockages.

GENERATION


an engine oil by several grades which can collapse critical oil film thickness. This reduction in viscosity will eventually lead to a reduction in the load-bearing capabilities of the oil and abnormal bearing wear will eventually occur.

Chemical effect

Diesel engine oils are blended with additives that have specific functions to perform, such as anti-wear, anti-oxidant, dispersant and detergent-type additives, to name a few. When large amounts of fuel are present in an engine oil, these additives become physically diluted which reduces their effectiveness. Diesel also contains unsaturated aromatic molecules which facilitate oxidation of the engine oil, resulting in a loss of the much-needed detergent additive responsible for neutralising acids generated in the engine oil as a result of the combustion process, extended oil use or high operating temperatures.

The loss of this detergency in the oil results in increased corrosion of internal metal surfaces. To make matters worse, diesel is also made of heavier hydrocarbons that can turn to wax when ambient temperatures drop. If a fuel tank contains summer-grade diesel and temperatures drop significantly, wax crystals can form, causing a blockage in the fuel filter.

Similarly, diesel fuel dilution in cold operating temperatures can cause waxing of the engine oil which could result in low oil pressures and oil starvation in severe cases. Final note in forensic profile: This

killer has been known to cause wash-down of oil on cylinder liners, accelerated top-end wear, as well as high blow-by condition and increased oil consumption.

The dirty killer

The second killer in our forensic profile is dust. This engine killer was responsible for 15% of all engine-related problems we detected in the last year. The dire consequences of dust entry are perfectly summed up by Jim Fitch of Noria Corporation, who maintains that the cost of excluding one gram of dirt is only about 10% of what it will cost you once you let it enter the oil. The earth’s crust is made of different types of rocks, (igneous, metamorphic etc.), that contain large amounts of silicon and aluminium oxides which contribute to the composition of natural soil and dust.

It is for this reason that silicon and aluminium are used as the main elemental indicators of dust entry in oil analysis. Due to the large volumes of air that engines take in through the induction system they are at high risk of dust entry and the resultant accelerated wear that takes place due to abrasion. Interestingly enough, it is the particle that has its smallest dimension of a similar size to the clearance involved that does the most damage. A particle smaller than the clearance will pass straight through doing little harm and a particle larger than the clearance will be unable to enter and do any damage. Dust does the most damage at the point of entry, so when an

engine has a dust entry problem, the type of wear that takes place is often related to the manner in which the dust enters.

For example, an oil sample showing evidence of dust entry and an increase in bottom-end wear indicates that dust is entering the engine oil directly and not passing the pistons and rings. Any dust which is in the oil will usually be pumped through the oil filter before entering the bearings. However, engine dust ingress takes place predominantly through the air intake. Efficient air filtration removes most of the dust ingested but the remaining dust that is not removed by the filters or cleaners consists of very small abrasive particles that could be 10 μm or smaller.

As a result of the small clearances between piston ring and liner bore, it is these small airborne dust particles that pose the biggest threat when leaks occur in the induction system. These dust particles will pass between piston, ring and cylinder and eventually become suspended in the oil. If that was not bad enough there is also the issue of load distribution. The thin oil film that separates working surfaces prevents direct contact between the surfaces, reducing the amount of friction and the rate of wear. This oil film also absorbs shock loads and helps distribute load over the whole surface. When a dust particle is introduced between the two surfaces it changes the loading of the surfaces from one of even distribution to a point load concentrated on the particle with tremendous pressure.

Fig. 3: Top-end dust entry. Fig. 4: Soot in oil sample.

GENERATION


Fig. 5: Internal coolant leak.

The dark killer

The third killer in our forensic profile is soot. This engine killer was responsible for 6% of all engine-related problems we detected in the last year. Let’s face it, burning fossil fuel is a dirty business and due to the inherent impurities and inefficient engine combustion cycles it is not possible to burn fossil fuel with 100% efficiency. One of the major combustion by-products of burning diesel is soot.

Soot is impure carbon particles resulting from the incomplete combustion of diesel. When formed in an engine the soot particles are vanishingly small in size (±0,03 μm), but with progressive fuel usage large quantities of these particles are deposited in the oil and eventually agglomerate to form larger soot particles. Soot enters the engine oil with exhaust gas in the form of blow-by, or is deposited on the cylinder walls and is then scraped off by the rings and deposited in the sump.

Combustion efficiency as well as the sulphur content of the diesel being used is directly related to the soot generation rate. Poor ignition timing, restricted air filter and excessive ring clearances cause high soot load. Engine design, fuel

quality and operational environment are also factors that contribute to the rate of soot deposited in the oil. All engine oils contain detergent and dispersant-type additives which control the effects of soot.

The detergent additive keeps metal surfaces free of deposits while neutralising compounds that can form sludge and varnish. The dispersant additive works by keeping insoluble contaminants (like soot) dispersed in the lubricant and prevent them from coating metal surfaces. However, these additives, like all oil additives, are sacrificial in nature and once used up they will not be able to protect the oil from degradation and continued soot accumulation or agglomeration.

The most dramatic effect of excessive soot is the viscosity increase which results in higher operating temperatures and accelerated wear. The oil might still be able to flow and provide sufficient lubrication at operating temperatures of 90°C but when it cools down to 10°C during the night the oil can solidify. Under these adverse conditions, when the engine is started, the oil pump will not be able to pump this solid mass leading to oil starvation.

Exhaust gas recirculation (EGR) units on diesel engines amplify the amount and abrasivity of soot production as the device channels the emissions back to the combustion chamber, creating a multi-pass opportunity for soot to deposit in the oil. Final note in forensic profile: This killer has been known to cause plugging of oil filters and galleries, additive mortality, increased operating temperatures and bearing seizure due to oil starvation.

The cool killer

Finally, the pièce de résistance of engine killers: the internal coolant leak. This engine killer was responsible for 13% of all engine-related problems we detected in the last year. This is the most brutal engine killer of them all, and a testament to this is the fact that major diesel engine manufacturers estimate that 53% of all catastrophic engine failures are due to cooling system problems.

So, what is the modus operandi of this coolest of engine killers you might ask? Generally, most coolants are a mixture of water, glycol and additives. The water acts as the heat transfer medium while the glycol component of the coolant raises the boiling point and lowers the freezing

point of the water it is mixed with. The additive portion of the coolant is there to protect metals in the cooling system from corrosion, cavitation, scale formation etc. Internal coolant leaks can sometimes be confusing as there is often no physical water present in the oil.

This is due to the operating temperatures and pressures in the engine, which ensure that the water evaporates off. However, the additives in the coolant will contribute to elemental concentrations of sodium, boron, potassium and silicon in the oil, and it is this elemental family from the coolant additive system that serves as a marker to confirm coolant contamination of the oil. Coolant can leak into engine oil in a variety of ways, such as from a defective seal, blown head gasket, damaged or corroded cooler core, or water pump seal failure, but one of the most common causes of an internal coolant leak is liner perforation.

Liner perforation occurs when the liners vibrate to the rhythm of the piston movement during the compression and combustion stroke. This movement causes pressure waves to form negative pressure regions that nucleate vapour bubbles. As the combustion chamber fires, these vapour bubbles implode and can literally blast small holes in the liner wall. The introduction of coolant into lubricating oil can expose your machine to a dangerous mixture of chemicals that can progress to engine failure in a short period of time. Below are just some of the known modes of attack this engine killer has displayed in past murder cases.

Viscosity change

Glycol contamination of engine oil can increase the oil’s viscosity, and this can lead to insufficient flow of the oil to critical metal surfaces. Added to this, glycol and its reaction by-products can also aggressively promote oxidation of the base oil which will further thicken the oil. Remember – if it’s too thick…it can’t flow…if it can’t flow…it can’t cool – so any dramatic increase in the oil’s viscosity will have an adverse effect on the oil’s cooling ability.

Oil filter plugging

The acids and water that form in engine oil as a result of coolant contamination can disrupt soot dispersancy. A prominent oil filter manufacturer claims that 75% of filter plugging complaints in engine oil filters involve coolant in the crankcase,

GENERATION


and that just 0,4% coolant in engine oil is enough to coagulate soot and cause dump-out, leading to sludge, deposits, oil flow restriction and filer blockage.

Abnormal wear

Glycol oxidises into corrosive acids which can cause a rapid drop in the oil’s alkalinity (Total Base Number), resulting in an unprotected corrosive environment which can increase corrosive wear of engine bearings and other internal metal surfaces.

Additive precipitation

Glycol can react with oil additives causing precipitation. ZDDP (Zinc dialkyldithiophosphate) is an important anti-wear and anti-oxidant additive found in almost all diesel engine oils. When the engine oil is contaminated with glycol, ZDDP will form reaction products and this leads to a loss of anti-wear and anti-oxidant performance.

Oil balls

Oil bal ls are abrasive spherical contaminants that form from the reaction of the detergent additives in the oil and glycol contamination. Oil balls are a

known cause of damage to crankcase bearings and other frictional metal surfaces in the engine.

Forensic profile close-out

The time taken for engine failure progression can vary significantly for the contaminants profiled in this technical bulletin. There are also several aggravating factors that can drastically shorten the failure development period, such as deficient maintenance practices, oil quality and filtration. Sudden-death engine failures from moderate concentrations of contaminants are usually accompanied by one or more of these aggravating factors, whereas high concentration of contaminants in an engine oil can result in sudden-death failure irrespective of any aggravating circumstances.

What is most commonly seen, however, is when the moderate scenario is unattended to by the engine operator and escalates over time until engine failure eventually occurs. Unfortunately, many engine operators are unaware of the danger engine oil contaminants create and what inevitable fate they can lead to in terms of equipment availability and lifecycle.

Protecting your engines and ultimately your equipment from the harmful effects of contamination and lubricant degradation begins with a proactive mind-set. An efficiently-run oil analysis programme can generate benefits in two distinct modes – namely the predictive maintenance and proactive maintenance modes. In the predictive mode an oil analysis programme can reduce the failure severity, maintenance costs and allow the user to plan maintenance activities. In the proactive mode an oil analysis programme can be utilised to identify the root cause of failure as well as reduce the failure rate.

The value of proactive maintenance lies in its ability to extend component life by controlling the root cause that can lead to engine failure. Hopefully from this technical bulletin it can be seen that the cumulative effect of oil contamination on engine reliability, fuel economy, exhaust emissions and maintenance cost can be considerable. Therefore, proactive maintenance techniques such as oil analysis are vital to mitigate the risk of engine failure.

Contact Wear Check, Tel 031 700-5460, [email protected] v

GENERATION NEWS



Clean energy powers healthcare facilities

With the increasing pressure to lower carbon emissions, the use of coal-fired equipment is phasing out. As part of the Green Initiative, the South African government has been encouraging and supporting alternative fuel options. Natural gas is one of the best options, being both effective and environmentally friendly. CNG Holdings, through its Virtual Gas Network division, recently installed compressed natural gas (CNG) equipment at Pholosong Hospital, Tsakane. The hospital chose to switch from coal to natural gas to provide steam for heating, cooking, and laundry. Pholosong Hospital houses tube trailer bays which are situated some distance from the boiler room with the gas piped to the plant. Through SAGA-approved registered gas practitioners, the company routed the pipes underground to avoid the risk of damage. Tube trailers are parked in dedicated bays and rotated when the gas supply runs low, at which point the company dispatches a replacement tube trailer.

Contact Wayne Williams, CNG Holdings, Tel 086 011-6917, [email protected] v

Capabilities added to backup power fuel cell

GenCell Energy, a leading Israel-based manufacturer of fuel cell energy solutions, recently announced newly-added capabilities to its G5 backup power fuel cell solution. These include dynamic peak load absorption of up to 100 kVA and advancements in Gencell’s IoT remote monitoring software – opening up a host of new commercial and industrial applications for this solution. With the ability to absorb even higher power loads, the G5 solution can now meet an even wider range of power needs for businesses. Specifically, those who require a clean and reliable backup power solution that can safeguard their critical assets during a grid outage of any duration, and as a result, ensure business continuity. These include hotels and other commercial properties (such as gas stations, convenience stores and banks), as well as public services like hospitals and fire stations. Multiple unit G5 solutions have the added benefit of employing a redundant microgrid configuration which further increases their power reliability and flexibility.

Contact Libby Alpert, GenCell, [email protected] v

Fuel gas receiving station commissioned

Energas Technologies recently commissioned a fuel gas receiving station for a new 340 MW power plant in the coastal city of Tema in Ghana. According to the company, the power plant has been designed to run predominantly on natural gas, but can also operate on distillate oil and light crude oil. The fuel gas station takes natural gas from the nearby pipe network and treats it before delivery to the plant’s gas turbines. The commissioning activities involved verifying all instrument loops, testing all safety systems, verifying the accuracy of the flow meter, commissioning the water-bath heaters and correct adjustment of the pressure regulators and slam-shut valves. Nitrogen was used to purge the piping to an acceptably low oxygen concentration prior to the introduction of natural gas.

Contact Laetitia Jansen van Vuuren, Energas, Tel 011 397-6809, [email protected] v

Innovative power solution for new portKohler-SDMO and its local partner, Select, recently won the tender, issued by the two shareholders of the new port of Doraleh in Dijbouti, for six 2 MVA generating sets. The generating sets are housed in CPU40 containers. They are coupled together in series and will supply power to the port and its cranes in the event of a mains outage. Two load banks were also added. When operating via the grid, a port crane draws electrical power when lifting a container. Conversely, when lowering a container, it generates electricity which the grid is able to access. In the event of electrical interruption, the load banks absorb this power. The power plant is supplemented by three 120 000 litre diesel tanks and a high-voltage equipment room. If the port is extended in the future, additional connections have been built into the design to be able to receive a further three generating sets.

Contact Hayley Porter, Diesel Electric Services, Tel 011 493-7079, [email protected] v

Company Projects Products TechnologyGENERATION NEWS


Agreement for sale of natural gas

Renergen, an integrated alternative and renewable energy business listed on the JSE’s Alt-X, recently announced that its subsidiary Tetra4, has secured an agreement with Black Knight Group for the sale of liquified natural gas. The transaction will fuel approximately one hundred trucks; significantly reducing carbon emissions and operator costs and improving vehicle lifecycle maintenance. The use of alternative fuels by suppliers continues to take centre stage, providing cleaner and safer solution for businesses as well as the environment. Black Knight Group, with 20 years’ experience in the fuel industry, has been distributing fuel products across South Africa and the wider SADC region. In recent years it has developed a logistics division aimed at providing holistic fuel solutions for clients. Tetra4, a vertically integrated gas producer, holds the first and (currently) only onshore petroleum production license issued by the Department of Mineral Resources through the Petroleum Agency of South Africa.

Contact Stefano Marani, Renergen, Tel 010 045-6000, [email protected] v

Series of natural gas generators launched

Cummins launched its HSK78G natural gas generator series recently. The series offers a total package of gas generator capabilit ies and innovative gas technology for prime and peaking power applications. With a power density of up to 2,0 MW from a 78 l engine, the new generator series is designed to provide rel iable power, regardless of the natural gas source or the climate, including extreme heat up to a blistering 55°C and extreme altitudes. This technology pushes new levels of efficiency, transient performance and gas variation well beyond former natural gas generators. The generators are suitable for a diverse set of industries from mining and manufacturing to shopping malls and hospitals. The new generator series have been designed to push the boundaries of performance to extremes while achieving a low total cost of ownership.

Contact Deepa Rungasamy, Cummins Africa, Tel 011 589-8500, [email protected] v

Ammonia engine developed

MAN Energy Solutions took a s igni f icant s tep towards developing an ammonia-fuelled engine. The engine will be based on its existing B&W Dual Fuel ME-LGIP Engine, which uses liquefied petroleum gas (LPG) as a low-emission fuel. There are two advantages to using an engine designed for dual fuel use. First, it provides confidence in fuel availability during a transition period when infrastructure is still under expansion, and secondly, it allows swifter decarbonisation of the existing fleet, because retrofits are possible. Ammonia can be burnt in an engine without producing any CO2 or carbon and may be stored either as a liquid at -34C or at normal temperatures under around 10 bar pressure. With ammonia, safety is paramount. While an advantage of using ammonia as a fuel is that it is not explosive, a disadvantage is that it is toxic. The two-stroke engine design is suitable for engine sizes from 5 to 85 MW, the company says.

Contact Jan Hoppe, Man Energy Solutions, [email protected] v

Assisting a drought-stricken communityWhen the Sarah Baartman District Municipality in the Eastern Cape, which includes drought-stricken Makhanda, was declared a local state of disaster area on 25 February, Engen heeded the community ’s call for help by donating 100 Jojo tanks which will be used at borehole sites for filtration purposes and at other sites such as schools, hospitals, clinics, old age homes and other distribution points where the community has access to safe drinkable water through the use of these tanks. Reduced dam levels on the west and damaged equipment on the east has led to a shortfall of 13 Ml of water per day. The town had been without water for the better part of a month.

Contact Gavin Smith, Engen, Tel 021 403-4312, [email protected] v


Traditionally CHP has been taken to mean generation of electricity from waste heat with a low power to heat ratio. Recent trends and developments have shown that systems which generate electricity and produce heat as a by-product can be used effectively on site to reduce energy costs for industrial ,commercial, institutional and even domestic users that have a need for both power and heat. Hospitals are proving to be an ideal application for such systems.

A common factor to hospitals is that the electricity standby generation and heat generation plants are separate and both produce waste heat. A previous article [1] made brief mention of the fact that CHP could be considered as an effective source of both heat and electricity, and that combining electricity generation with heat generation could produce a system with a lower total energy cost than using grid power and separate heat generation.

Hosp i t a l s have two pa r t i cu la r characteristics of energy:

l The hospital operates on a 24/7 basis and requires highly reliable energy sources.

l The hospital requires a continuous supply of heat energy as well as electrical energy

Electricity requirements

Electricity demand in South African hospitals ranges from 5000 kVA for a large institution to 50 kVA for a small clinic type hospital. Hospitals require a highly reliable supply of electricity, and most are equipped with diesel/alternator standby plant, to run essential services in the case of grid failure. Hospitals must perform critical, life-saving functions even when a widespread disaster interrupts their supply of electricity from the utility grid. CHP systems can be designed to maintain critical life-support systems, operate independently of the grid during

emergencies, and be capable of black start (the ability to come online without relying on external energy sources). Hospitals regularly experience failures with backup power systems during grid outages, and CHP systems can offer a more seamless, reliable power alternative than traditional emergency generators, because they are already up and running. HP systems, however, are not automatically configured for backup capability; hospitals must ensure that the systems have automatic transfer capability and that output can be matched with demand

Heat energy requirements

Most larger hospitals rely on a central heating system which is used to provide hot water for washing and space heating, and low grade steam for sterilisation, cooking and other uses. Central boiler systems generate steam which is distributed to the various functional units. Boilers are the biggest single energy consumption item in many older hospitals. Older facilities use steam as a means to provide heat for space heating, sterilisation (autoclaves), cooking, hot water generation and other applications. The centralised supply of heat proved to

be the most efficient in the past and many South African government hospitals are fitted with coal boilers.

Heat requirements for some functions, such as food preparation, have changed, but there is still a large requirement for a central heat supply in most hospitals. The requirement is for low quality (low temperature) steam and boilers used are of the coal grate feed type. In the past hospital heat was supplied by coal fired boilers. The Johannesburg general hospital boiler system used three tonnes of coal per day. Many hospital boilers have been converted to firing with natural gas or LPG, but the heat demand still remains.

Advantages of CHP for hospitalsl Lower, more predictable energy bills:

Total system energy efficiency is improved when power is produced onsite through a CHP system. Annual operations and maintenance savings can be substantial. By enabling hospitals to supply their own power, CHP systems also provide a hedge against the rising cost of electricity.

l CHP systems often can be installed for less upfront costs than renewable

Improved energy security at low cost for healthcare facilities

Mike Rycroft, EE Publishers

Many south African hospitals are converting from coal fired to gas fired boilers because of cost savings and lower environmental problems, as well as fuel transport and storage issues. Combined heat and power (CHP) systems, based on gas, can provide the hospitals heat needs as well as reliable electricity at a competitive cost.

Fig. 1: Combined cycle gas turbine CHP system.

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use available exhaust thermal energy from the prime mover, the greater the system efficiency and the greater the energy saving achieved by the CHP system. As a general rule of thumb, experts suggest that 50% or more of annual available thermal energy from the prime mover should be used to make a system economically viable. Hospitals make good candidates for CHP systems because they tend to have fairly significant coincident electric and thermal loads over the course of the day [3].

Hospitals using boilers to provide steam and water heating could benefit from

Table 1: Power to heat ration of several CHP systems.

Table 2: Fuel cell performance characteristics.

Characteristic

Technology

ICE Gas turbine Microturbine Fuel cell Steam

turbine

Size range10 kW to 10 MW

1MW to 300 MW

30 to 330 kW5 kW to 28 MW

100 kW to 250 MW

Electrical Efficiency(%) 30 to 42 24 to 36 25 to 29 38 to 42 5 to 7

Power to heat ratio 0,6 to 1,2 0,9 to 1,3 0,5 to 0,8 1,3 to 1,6 0,07 to 0,1

Overall CHP efficiency (%) 77 to 83 65 to 71 64 to 72 62 to 75 80

Fig. 2: ICE cogeneration system for hospitals (Clarke energy).

energy options: Photovoltaic systems, for example, of a similar scale. When matched to suitable loads, some CHP systems can provide a simple payback in the five- to ten-year range, depending on system size and energy costs.

l CHP plant acts as a standby electricity source in case of grid failure: Where the CHP can act as a bridging supply while a standby plant starts up. In some installations the CHP plant forms the main supply or standby plant itself. Unlike emergency generators, which are “dead assets” only to be employed in critical instances, the CHP plant is a “dynamic asset”, which provides economic returns while running every day.

Power to heat (P/H) ratio

This is an important factor when considering the use or selection of CHP plant for a hospital, and is defined as the ration of the electrical power produced to the thermal power produced. For consumption, it is defined as the ratio of electrical energy to thermal energy required by the energy consuming facility. For an energy producing system such as a CHP plant, it can be defined as the ratio of electrical energy to thermal energy produced.

Traditional CHP systems, which use waste heat to generate electricity, have low power to heat ratios, of the order of 0,3. The CHP considered for this application, reverses the priorities to a system that primarily produces electricity, with heat as a by-product and required P/H ratios of 1,5 and higher. Some micro CHP plant is designed for a P/H ratio of 6. Table1 gives the P/H ratio of several common CHP plants.

CHP systems for hospitals

The total heat and electricity load will depend on both the type and size of the healthcare facility. The system chosen will depend on the combined heat power load. Systems may be sized based on either the electric or the heat load. Most hospital CHP systems are sized for the thermal load requirements with the resulting electric power generated used to first offset the power purchased from the utility grid (excess power can be sold to the utility) [2].

The primary purpose of these systems is electricity generation and the name should logically be combined power and heat (CPH) systems, to differentiate from systems whose primary purpose is

heat production. However, for reasons of clarity, this article will continue to use CHP. The combined heat and power requirements of a hospital will depend on the size of the facility, but most will range between hundreds of kilowatts and several megawatts, an ideal range for the application of small gas turbines, IC gas engines and fuel cells.

To achieve high efficiency in a CHP system, facilities should have significant demand for heating (or cooling) and electricity at the same time. This is known as thermal and power coincidence. The greater the ability of a facility to

Fuel cell typePhosphoric acid (PAFC)

Proton exchange membrane (PEMFC)

Molten carbonate (MCFC)

Solid oxide (SOFC)

Nominal electric capacity (kW)

200 200 1200 125

Electrical efficiency

33 35 43 43

Power/heat ratio 0,8 0,85 2,16 1,25

Operating temperature (°C)

190 to 210 65 to 85 650 to 700 750 to 1000

Heat output( kW) 250 210 556 100

Total CHP efficiency (%)

81 72 62 77

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combined heat and power (CHP) systems with natural gas-to-power generators and the exhaust gas to provide heat. The CHP system can provide a portion of the hospital’s electricity demand as well as steam and chilled water. Several hundred CHP systems are installed in hospitals worldwide using one of the following options:

l Gas turbine generator (GT): The outlet gas is fed to a heat recovery system where it produces steam which in turn can be used to produce hot water as well as for other functions. This can replace the hospital boiler system while generating electricity.

l Internal combustion engine (ICE) driven generator: Exhaust gas from the engine, is passed through a heat recovery system which generates hot water, and can also provide chilled water. This option is suitable for installations with a lower electrical and heat load.

l Fuel cell (FC) generator: Heat is derived from the FC exhaust and from the FC cooling system. The type and quality of heat depends on the type of fuel cell used and can range from low quality hot water to medium pressure steam.

Gas turbines

Gas turbines based CHP systems for operation in hospitals can be of several types

l Open cycle with steam generation: In this configuration the outlet of the gas turbine is used entirely for generation of heat for hospital use. The outlet gas is fed to heat exchangers which produce hot water and steam. Gas turbines with Heat recovery steam generators are a cost-effective CHP option for power demand usually between a few MWe and 25 MWe. They perform best at full power although they can also be operated at partial load. Waste heat is recovered in the heat recovery steam generator (HRSG) to generate high- or low pressure steam or hot water. The thermal output can be used directly or converted into chilled water by single or double-effect absorption chillers.

l Combined cycle GT systems: In this configuration, the exhaust gas is used to generate steam which drives a back pressure steam turbine which generates further electricity and delivers low pressure steam to the hospital. The exhaust gas may also be used to generate high pressure

steam and hot water directly as shown in Fig.1

IC gas engines with cogeneration or trigeneration (T/C)

In the co-generation system system heat is extracted from the exhaust gas and engine coolant to produce steam and hot water as shown in Fig. 2.

There are severa l non-hosp i ta l installations in South Africa using trigeneration (TG) at the moment. TG uses a gas IC combustion engine to generate electricity. Heat is recovered from the exhaust gas by a heat exchanger to produce hot water and low grade steam. Heat from the exhaust gas is also fed to an absorption chiller to produce chilled water for air conditioning. Typical systems are of the order of 1 MW electrical capacity. Trigeneration plants with about 2MW capacity have been planned for six Gauteng hospitals [7].

Fuel cell CHP

Fuel cells have the advantage that they

are available in sizes ranging from tens of kilowatts to several MW. A range of fuel cell types can be considered for CHP operation in hospitals. Fuel cells generate both heat and electricity directly. A typical fuel cell construction is shown in Fig.2 and Table 2 lists some the performance characteristics of common types.

Heat is recovered both from the stack cooling system and the exhaust gas. The type of fuel cell used for CHP will depend on the quality of the heat required. CHP Fuel cells systems are optimised for heat production and heat is usually extracted from the exhaust gases. Heat may be extracted from Fuel cells in two ways:

l From the internal cooling circuitl From the exhaust gases

The heat abstraction from PEMFC and SOFC systems is markedly different. For PEFCs, heat is usually extracted from the circulating cooling liquid that passes through the cooling plates situated throughout the fuel cell stack. This leaves

Fig. 3: Typical fuel cell construction.

Table 3: Fuel cells installed in hospitals in the USA.

Model Electrical output

Total Heat output

% of electrical demand met

Heating requirement met

PC 25 200 kW 260 kw 10% Space heating

DFC 1500 1,4 MW 1,0 MW 42% Space heating

Purecell 400 460 kW 500 kW 60% Space heating

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the stack at 80° C, which is an ideal temperature for space heating and hot water (giving 40 – 70° C after accounting for heat exchanger losses.

For SOFCs, the cathode air flow is used as the stack coolant. The excess air and unconsumed fuel leave the stack at its operating temperature and can be combusted in the afterburner, heat from which services the pre-reformer (if present) and preheats the reactant streams entering the stack. Excess high grade heat is available for hot water and space heating. Since the temperature of the exhaust stream (100s of °C) is higher than that of the PEMFC cooling circuit (80°C), heat transfer to the thermal circuit of the installation is more efficient [2].

Heat is generally recovered in the form of hot water or low-pressure team, but the quality of heat is dependent on the type of fuel cell and its operating temperature. PEMFC operate at temperatures below 100°C, and therefore have low quality heat. Generally, the heat recovered from fuel cell CHP systems is appropriate for low temperature process needs, space heating, and potable water heating. In the case of SOFC and MCFC technologies, medium pressure steam can be generated from the fuel cell’s high temperature exhaust gas, but the primary use of this hot exhaust gas is in recuperative heat exchange with the inlet process gases, where natural gas is used as the fuel. If pure hydrogen is used as a fuel, the full thermal capacity of the exhaust is available for heating.

The simplest thermal load to supply is hot water. The primary application for CHP in healthcare facilities is hot water and space heating/cooling. Several hospitals in the USA have installed fuel cells as a CHP option, although the heat component is mainly being used for space heating. Table 3 lists the properties of the units used.

Fuel cells are an interesting option in South Africa, with the development path towards a hydrogen economy and hydrogen/platinum development path in this country. Fuel cells now run off gas, but in future may run off renewable hydrogen produced from surplus renewable electricity.

The South African situation

All of the above systems use gas as a fuel. SA does not have an extensive natural gas network, although there are developments in that direction. Alternatives which are finding application are bulk LPG storage on site and bulk compressed natural gas (CNG). A local company has established what it calls a “virtual gas network” (VGN) based on CNG [5]. At least two one local hospital has converted the boiler system to CNG making use of the VGN [5], and a number of residential estates and business parks are offering piped gas based on on-site bulk LNG storage. There is thus a very strong potential for hospitals to use CHP. At least one healthcare centre in South Africa is using fuel cells as a power source, although only for the electricity supply.

References

The references for this article can be found with the online version at https://wp.me/p5dDng-1ahK


Nedbank and EE Publishers launch energy and ICT infrastructure seminars

Nedbank and EE Publishers will host a series of morning seminars on important infrastructure issues facing the energy and ICT sectors in South Africa at Nedbank main auditorium, 135 Rivonia Road, Sandton.

The purpose of the seminars is to initiate meaningful, constructive dialogue on energy and ICT infrastructure initiatives needed to unlock the economic and human potential of South Africa.

The seminars will cover political, economic, environmental, policy, legal, regulatory, planning, investment, business, labour and social issues. Attendees will be addressed by a number of key sectoral leaders, followed by open discussion and dialogue with the audience on the challenges arising. An entrance free of R150 pp will be levied. Register here: https://bit.ly/2I7tdYo

7 May 2019: Ensuring a just energy transition

The need for a just energy transition in South Africa to ensure environmental sustainability and reduce the carbon intensity of South Africa – issues of job creation, education, training, re-skilling and geo-location of clean energy resources for maximum impact and least cost.

25 Jun 2019: Enabling SSEG in SA

The role of small and medium scale embedded generation and ”smart grid” in meeting the electrical energy needs of the future – the necessary business case, policy, regulatory and financing environment for behind-the-meter solutions such as rooftop solar PV and other distributed generation.

13 Aug 2019: Establishing a viable gas sector

How to facilitate a viable gas sector in SA from imported liquefied natural gas (LNG), imported compressed natural gas (CNG) from neighbouring countries, liquefied petroleum gas (LPG) from the SA petrochemical industry, and exploration and exploitation of shale gas in the Karoo and natural gas along the SA coast.

22 Oct 2019: Flexible power generation

The role and business case for flexible generation, including gas-to-power, pumped water storage, thermal energy storage and battery energy storage systems to complement intermittent wind and solar renewable energy sources, and to provide much needed auxiliary grid services.

26 Nov 2019: Supporting effective ICT ecosystems

The need for effective ICT bandwidth, spectrum and infrastructure, together with a sound policy, legal, regulatory and planning framework in South Africa, to facilitate universal affordable broadband access, e-business and Industry 4.0 for inclusive economic growth.

For more information please visit https://wp.me/p5dDng-18dg

Contact Charmaine Manicom, EE Publishers, Tel 011 543-7000, [email protected] v


A modern, decentralised energy and heat supply will bring production closer to consumers in the future. For this purpose, three large cogeneration units were implemented: one at the university hospital and two at the university.

Fifty percent of the electricity requirement

At the end of September 2017, the “heart” of the new combined heat and power plant of UMG, a gas engine with generator, was delivered. A heavy-duty crane lifted the 53-ton unit into the new building. The engine and generator alone account for around one million euros. Since the end of 2017, the first of the three power plants has now been supplying about half of the electricity required and the basic heat requirement of the university hospital. The 4,5 MW cogeneration plant was developed and supplied by ETW Energietechnik, the Moers-based specialist for power plants. It contributes around 50% to the electricity requirements of the University Hospital Göttingen. The total efficiency of the energy utilisation, electricity and heat output, amounts to about 90 percent.

Contribution to climate protection

The state of Lower Saxony will bear the costs of around €4,7-million from the August 2014 “Rehabilitation Programme for University Medicine of Lower Saxony” campaign, but the investment will not only save energy costs; security of supply and the saving of 6500 tCO2/y will also make an important contribution to climate protection.

Security of supply elementary core component

Security of supply in particular is a key element of the new energy concept. The University Medical School Göttingen (UMG) as a clinic of maximum care has an annual heat energy requirement of more than 33 000 private households. For this purpose, the waste heat from the

engine and the hot exhaust gases are decoupled and used for their own use. UMG relies on a cogeneration plant for the generation of heat and electricity, which generates energy particularly efficiently with continuous heat output. It has a heat output of 4,75 MW and has a 33-meter-high chimney stack.

Base load of heat supply

Since January 2018, around half of the electricity required in the university hospital has been produced, thus covering the basic load of heat supply for the hospital. The heat is mainly used to heat the drinking water and for the room heating of the central hospital building. The energy-efficient plant technology of the CHP reduces the consumption of resources and reduces environmental pollution and emissions. “The new combined heat and power plant is thus an important contribution and a good example of the integration of biogas into sustainable and modern energy supply concepts”, says Dr Oliver Jende from ETW Energietechnik in Moers.

Power generation close to main consumers

The two subfoundations University Medicine Göttingen (UMG) and the University of Göttingen coordinate their joint “energy policy” and founded the Universitätsenergie Göttingen in 2009. Their goal: Both partners want to use the energy required for the foundation university efficiently, in an environmentally friendly and cost-effective manner. The core of the energy supply concept is to bring power generation close to the main consumers in order to minimise transmission losses.

T h e U M G h a s a n a n n u a l e lectr ic i ty requirement of about 57 GWh of electricity and about 100 GWh of heat, the university of 5 0 G W h o f e l e c t r i c i t y a n d 67 GWh of heat. In the UMG, electricity and heat are also used for central cooling production.

Contact Oliver Jende, ETW Energietechnik, [email protected] v

University and medical school receive modern clean energy supply

Information from ETW

The basic supply of electricity and gas to the economy is one of the pillars of the Energy Industry Act. However, the safe and reliable supply of energy is even more essential in the medical sector. Both electricity and heat can save lives here. In order to ensure this security of supply in the future, the University of Göttingen (UMG) and the University of Göttingen have jointly initiated an innovative energy supply concept.

Fig. 1: ETW Energietechnik installs the unit in a building of the University Hospital.

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Gas-powered industrial scale dust extractor

Dustcontrol UK will showcase the firm’s new DC Storm LPG, its powerful Tromb 400 extractors, the DC 2900 and DC 1800 eco vacuums and its DC Aircube cleaners at the upcoming Safety & Health Expo 2019 from 18 to 20 June in London. The innovative propane-driven DC Storm LPG came to market last year and can remove hazardous dust on an industrial scale. The Storm LPG is cyclone based, Hepa 13 filtered and built to application class H as standard for a no compromise approach to performance and dust containment. Lasting up to eight hours, the robust machine’s 15 kW motor has the capacity to manage dust extraction in conjunction with work involving large-scale concrete construction and brickwork projects. Operating without the use of cables, this dust extractor is ideal for environments with a limited supply of electricity.

Contact Dustcontrol, Tel 013 2785-8001, [email protected] v

Almost 90 years of power solutions

Founded in Denmark in 1933, Danfoss is a leading supplier of energy-efficient power solutions. The company is, among others, a provider of mobile hydraulics for the construction, agriculture and other vehicle markets, and has pioneered orbital motors and steering units. Danfoss Cooling engineers and develops energy-efficient cooling technologies; encourages the use of natural refrigerants; helps to reduce overall emissions and integrates renewable energy. In terms of heating, Danfoss products and services are used in conditioning, smart home heating and building optimisation. The company also manufactures AC drives and it is estimated that, by 2025 over 5-billion people will benefit from the benefits of its drives. Its industrial automation division is a global player in developing fluid, pressure and temperature controls, producing 250 000 items per day in 70 factories at 25 locations world-wide. Danfoss High-pressure Pumps develops and manufactures high-pressure pumps and energy recovery devices. It has pioneered the development of axial piston pump technology and brought positive displacement pumps to high-pressure applications.

Contact Roland Sargent, Danfoss, Tel 011 785-7600, [email protected] v

Installation tester protects appliances

Comtest is offering the Fluke 1660 series installation tester with Fluke Connect, which includes the 1664 installation tester, the only installation tester that helps prevent damage to connected appliances during insulation tests, and also allows users to send test results wirelessly via smartphone directly from the field. This series of multifunction installation testers fully fulfill the requirements for combined measuring equipment, and the three different models in the series comply with specific parts of this norm. They are specifically designed to carry out the tests specified, and all local standards and regulations in the safest and most efficient way.


Oil-free compressors assist automotive factoryLocal provider of portable air and power Rand-Air was recently requested to hire two diesel oil-free compressors to a local facilities management company, for use at the end-customer’s local motor vehicle manufacturing plant. The vehicle manufacturer’s plant has become the nerve centre of the company’s South African operations. Over the past four decades, it moved from operating as a production plant assembling vehicles with limited customisation possibilities for the local market only, to a world-class facility, capable of producing customised cars for discerning customers across the globe. The customer required two of the largest Atlas Copco 1500 cfm compressors over a period of some two weeks. While other companies might offer oil-free compressors, their air output does not have the same 100% contaminant-free air quality which Rand-Air’s Class-0-rated oil-free compressors have.

Contact Byrone Thome, Rand-Air, Tel 011 345-0700, [email protected] v

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Collaboration on mechatronics academyElectroMechanica has collaborated with Polytech Africa to establish the first Mechatronics Academy to be accredited by the Manufacturing, Engineering and Related Services Sector Education and Training Authority (merSETA). Creating such an academy has been the lifelong dream of Polytech Africa Founding Director Astrid Straussner, who has over 20 years’ experience in the education and engineering fields. Polytech Africa is a Level 4 Broad-based Black Economic Empowerment (B-BBEE) accreditation. The academy will focus on the National Qualifications Framework (NQF) Level 2 learnership. This is based on essential aspects of precision mechanical engineering, electronics, and computer design systems used to control and automate mechanical products with electrical signals. Here Electromechanica plays a vital role, as its products include the Delta industrial automation range. Upon completion of NQF Level 2, certificate holders can gain entry to highly-skilled sectors such as mechanical and electrical engineering; pneumatics and hydraulics; robotics; programmable logic controllers (PLCs), and computer numeric control (CNC).

Contact Karen Zotter, ElectroMechanica, Tel 011 249-5000, [email protected] v

Tools for construction sites

Comtest has on offer Fluke cons t ruc t ion ins t ruments including laser levels engineered to stay within specification, even after a one-meter drop. Whatever electricians, HVAC engineers, surveyors, inspectors, b r i c k la ye r s , ca rpen te r s , roofers and plumbers need measured (including distance; temperature; cable location; electrical values and indoor air quality), Fluke has the tools. The engineered but simple, intuitive operation of Fluke tools means users don’t need to refer to manuals, translating into time saved per measurement. This soon amounts to cumulative labour cost savings. Besides carrying out their primary job function, construction engineers a re i n c r ea s i ng l y ca l l ed upon to inspect the work of carpenters, tilers, brick-layers and plasterers. Should they not be able to do this, they risk significant waiting time and, at worst, can jeopardise the quality of the entire job.


Energy company acquires water treatment plant

Energy Partners Water (EP Water) recently announced its merger with water purification specialist, Venus Water Treatment, after concluding the purchase of a 100% stake in the company. The merger adds significant manufacturing and project execution capability to EP Water’s portfolio. With the capabilities acquired through this merger, the company will be better able to provide containerised water plants that are designed according to clients’ exact requirements and are easy to deploy on site. For Venus Water’s existing client base, the merger allows them to benefit from the outsourced service model that Energy Partners has already perfected throughout all of its divisions. This means that clients may enter into a water treatment agreement with Energy Partners and pay only for the water they use, without needing to invest any upfront capital to acquire treatment equipment.

Contact Manie de Waal, Energy Partners Water, Tel 021 941-5140, [email protected] v

Drive controllers provide crystal-clear benefits

Zippe Industrieanlagen is one of the world’s leading experts when it comes to handling raw materials in the glass industry. The company builds automated equipment to spec i f ic cus tomer requirements. For many years now, it has been using Siemens control, drive and measuring technology and is therefore able to set new standards for efficiency, performance and operator comfort with its ingenious concepts. Simatic S7-1500 advanced controllers from Siemens have established themselves as the basis of highly complex automation solutions for Zippe batch plants. The glass industry is not immune to the rapid developments coming out of Industrie 4.0. The international plant builder Zippe Industrieanlagen knows this and therefore includes integration and networking in its automation solutions. Two of the company’s successfully completed projects in Italy and Mexico show how the associated potential can be best exploited with the integration of Siemens components.

Contact Jennifer Naidoo, Siemens, Tel 011 652-2795, [email protected] v




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Appointments

Thabani Dlamini, Accounts assistant, WearCheck

Bianca Louw, Data capturer, WearCheck

Seen at the recent Power and Electricity World Africa exhibition

Thamsanqa Shongwe, In-house instrumentation technician,

WearCheckQuentin Gustav von Kleist, Technical

support consultant, WearCheckSella Patience, Laboratory supervisor, WearCheck

Power Electrical Engineering Industry EventsPEEI EVENTS


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Enabling SSEG in SANedbank Main Auditorium, 135 Rivonia Road, Sandton25 June 2019

The role of small and medium scale embedded generation and “smart grid” in meeting the electrical energy needs of the future – the necessary business case, policy, regulatory and financing environment for behind-the-meter solutions such as rooftop solar PV and other distributed generation.


Actom ...................................................................................................................... OBCAberdare Cables ...........................................................................................................29Dehn Africa ..................................................................................................................15Eaton ...........................................................................................................................11ICT Infrastructure ......................................................................................................... IFCLucy Electric .............................................................................................................. OFCMesse Hannover ...........................................................................................................21Reinhausen SA ................................................................................................................2SA GeoTech 2019 ....................................................................................................... IBCVoltex ...........................................................................................................................19WearCheck ...................................................................................................................37Zest ..............................................................................................................................25

Ensuring a just energy transition Nedbank Main Auditorium, 135 Rivonia Road, Sandton7 May 2019

The need for a just energy transition in South Africa to ensure environmental sustainability and reduce the carbon intensity of South Africa – issues of job creation, education, training, re-skilling and geo-location of clean energy resources for maximum impact and least cost.


PowerGen Africa 2019 CTICC, Cape Town14 – 16 May 2019

PowerGen Africa 2019 provides a platform to engage with peers, seek out best practice, and learn about the success stories in Africa and from around the world which can be implemented in your businesses. This event offers the power industry opportunities to make positive change in the region.

Contact Clarion Events, [email protected] v

27th AMEU Technical ConventionCTICC, Cape Town13 – 16 October 2019

Topics will include revenue collection and non-technical losses; the Internet of Things; smart cities and smart grids; evolving technologies; digital substations; productivity enhancement through robotics; advanced distribution automation; realigning customer service; etc.

Contact Mpho Motloutsi, AMEU Secretariat, Tel 011 061-5000, [email protected] v

Cigré regional conference 2019

Misty Hills Country Hotel, Conference Centre and Spa

1 – 4 October 2019

The conference will provide a platform for discussions between electric utilities, system operators, regulators, manufacturers and suppliers, universities, standardising bodies, research laboratories and authorities on topics in the field of the development of electrical systems in Africa.

Contact Anelja de Bok, Cigre, Tel 082 902-4606, [email protected] v

African Utility Week CTICC, Cape Town14 – 16 May 2019

Along with multiple side events and numerous networking functions, African Utility Week boasts a 6-track conference with over 300 expert speakers. Over 7000 decision-makers attend this annual event, which is the ideal place to source solutions, generate business and connect with new and existing energy markets.

Contact Zara Eckles, African Utility Week, Tel 071 700-3541, [email protected] v

Organised and hosted by

Dates: Monday & Tuesday 22 & 23 July 2019Venue: Emperors Palace | Johannesburg | South Africa

www.SAGeoTech.co.za

� emeGeo-tech to drive new business opportunities and economic growth

A geo-technology conference and expo for social, economic,business and infrastructure development and economic growth

Organised and hosted byOrganised and hosted by

www.SAGeoTech.co.za

Dates: Monday & Tuesday 22 & 23 July 2019Venue: Emperors Palace | Johannesburg | South Africa

� emeGeo-tech to drive new business opportunities and economic growth

A geo-technology conference and expo for social, economic,business and infrastructure development and economic growth

Conference and Exhibition

DesignTech | ArchiTech | MeasureTech | PositionTech | MineTech | ConstrucTech

ACTOM (Pty) Ltd. 2 Magnet Road, Knights, Boksburg, 1413, South Africa. Tel: +27 (0) 11 820 5111 www.actom.co.za

ACTOM (Pty) Ltd: 2 Magnet Road, Knights, 1413 | PO Box 13024, Knights, 1413Tel: +27 (0) 11 820-5111 | Fax: +27 (0) 11 820-5044 | www.actom.co.za

ACTOM is the largest manufacturer, solution provider, repairer, maintainer and distributor of electro-mechanical equipment in Africa.

ALWAYS WITH YOU

€¦ · Organised and hosted by Dates: 28 – 29 August 2019 Venue: Emperors Palace Convention...

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