NEW TECHNOLOGIES TO FACILITATE INCREASED LEVELS...
Transcript of NEW TECHNOLOGIES TO FACILITATE INCREASED LEVELS...
NEW TECHNOLOGIES TO NEW TECHNOLOGIES TO NEW TECHNOLOGIES TO NEW TECHNOLOGIES TO FACILITATE INCREASEDFACILITATE INCREASEDFACILITATE INCREASEDFACILITATE INCREASED LEVELS LEVELS LEVELS LEVELS OF DISTRIBUTED GENEROF DISTRIBUTED GENEROF DISTRIBUTED GENEROF DISTRIBUTED GENERATIONATIONATIONATION
CONTRACT NUMBER: DG/DTI/00039/05/00
URN NUMBER: 06/1829
The DTI drives our ambition of ‘prosperity for all’ by working to create the best environment for business success in the UK. We help people and companies become more productive by promoting enterprise, innovation and creativity.
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NEW TECHNOLOGIES TO NEW TECHNOLOGIES TO NEW TECHNOLOGIES TO NEW TECHNOLOGIES TO FACILITATE INCREASEDFACILITATE INCREASEDFACILITATE INCREASEDFACILITATE INCREASED LEVELS LEVELS LEVELS LEVELS OF DISTRIBUTED GENEROF DISTRIBUTED GENEROF DISTRIBUTED GENEROF DISTRIBUTED GENERATIONATIONATIONATION
CONTRACT NUMBCONTRACT NUMBCONTRACT NUMBCONTRACT NUMBER ER ER ER
DG/DTIDG/DTIDG/DTIDG/DTI/000/000/000/00039/05/0039/05/0039/05/0039/05/00
URN NUMBERURN NUMBERURN NUMBERURN NUMBER: 06/1829: 06/1829: 06/1829: 06/1829
This work was commissioned and managed by the DTI's Distributed Generation Programme in
support of the Technical Steering Group (TSG) of the Distributed Generation Co-ordinating
Group (DGCG). The DGCG is jointly chaired by DTI and Ofgem, and further information can be
found at www.distributed-generation.gov.uk
ContractorContractorContractorContractor
P B Power
The work described in this report was carried out under contract as part of the DTI Technology Programme: New
and Renewable Energy, which is managed by Future Energy Solutions. The views and judgements expressed in this report are those of the contractor and do not
necessarily reflect those of the DTI or Future Energy Solutions.
First published 2006
Crown Copyright 2006
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Project Steering Group SummaryProject Steering Group SummaryProject Steering Group SummaryProject Steering Group Summary
To implement the recommendations of the DTI/Ofgem report on Embedded Generation, a
Distributed Generation Co-ordinating Group (DGCG), together with a supporting Technical
Steering Group (TSG) was established. A number of workstreams were formed by the TSG -
one of which, Workstream 5 (WS5) is focussed on long-term network solutions. An issue
addressed by WS5 was to establish what new technology was likely to become available by
2010.
WS5 commissioned a Report, via Future Energy Solutions, from PB Power with the following
principal objectives:
1. To identify what new technologies are available or emerging (in UK and world-wide) to
facilitate increased levels of Distributed Generation (DG) in the time frame to 2010; and
2. To provide a summary of the status of emerging technologies to help inform decisions about what further work might be appropriate in this area.
The Report considered network-related technologies - including primary and secondary plant,
telecommunications and IT. Generation-related technologies were omitted except where they
formed part of a wider network solution. In compiling the Report the authors considered
technologies that may not yet be fully developed, commercially available, or are cost effective
but which would have the potential to be so by 2010.
The Report identified that the technologies likely to have the most impact on the connection of
additional generation were super-conducting fault current limiters, in-line voltage regulators,
micro-grid controllers and reactive power compensators such as SVCs, FACTs and STATCOMs.
Some of these technologies would be commercially available well before 2010, other may be
still at the ‘demonstrator’ stage by that time.
In commissioning the Report it was not the intention of WS5 to provide an exhaustive list of
emerging technologies, research, development and demonstration projects and initiatives
being undertaken by manufacturers. The intention was to understand what new technologies
were emerging to inform decisions on what might be done to eliminate barriers for the
introduction of DG. Whilst particular new technologies might be noted as being developed by
a certain manufacturer, it should not be interpreted as being solely developed by that
manufacturer or to be the only new technologies being developed by that manufacturer.
A number of areas were identified where additional work may be required to remove potential
barriers to the connection of additional generation. The successful connection and operation of
large quantities of distributed generation will require a high-speed reliable communications
network to be established. No standards were identified which cover communications
protocols between the substations and remote devices on the distribution system.
The Distribution Working Group (DWG) of the Energy Network Steering Group (ENSG) will
need to consider the issues raised in the report and ensure that they are taken into account in
scoping work programmes.
The WS5 P10 Project Group
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CONTENTSCONTENTSCONTENTSCONTENTS
Page No.Page No.Page No.Page No.
1. INTRODUCTION................................................................................................................1
2. STUDY METHODOLOGY..................................................................................................3
2.1 Literature Searches ...................................................................................................3
2.2 Internet Searches.......................................................................................................3
2.3 Questionnaires and Interviews ................................................................................3
3. INTERVIEWS AND QUESTIONNAIRES...........................................................................5
3.1 Interviews ...................................................................................................................5
3.2 ABB .............................................................................................................................5
3.3 AREVA.........................................................................................................................6
3.4 Econnect.....................................................................................................................6
3.5 Remsdaq.....................................................................................................................7
3.6 University of Manchester .........................................................................................7
4. PRIMARY PLANT TECHNOLOGIES.................................................................................8
4.1 Introduction................................................................................................................8
4.2 Transformers..............................................................................................................8
4.3 Overhead Lines and Cables....................................................................................11
4.4 SVCs, FACTs and STATCOMs................................................................................14
4.5 Switchgear and Fault Current Limiters .................................................................16
5. SECONDARY PLANT TECHNOLOGIES.........................................................................20
5.1 Introduction..............................................................................................................20
5.2 SCADA Systems and Substation Automation.....................................................20
5.3 Communications Systems......................................................................................25
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6. PRIMARY PLANT RESULTS SUMMARY ......................................................................28
6.1 Transformers............................................................................................................28
6.2 Overhead Lines and Cables....................................................................................31
6.3 SVCs, FACTS and STATCOMs ...............................................................................32
6.4 Switchgear and Fault Current Limiters .................................................................34
7. SECONDARY PLANT RESULTS SUMMARY................................................................36
7.1 SCADA Systems and Substation Automation.....................................................36
8. CONCLUSIONS...............................................................................................................38
8.1 Transformers............................................................................................................38
8.2 Overhead Lines and Cables....................................................................................38
8.3 SVCs, FACTS and STATCOMs ...............................................................................39
8.4 Switchgear and Fault Current Limiters .................................................................39
8.5 SCADA Systems and Substation Automation.....................................................39
8.6 Communications Systems......................................................................................40
8.7 Others .......................................................................................................................40
8.8 Summary..................................................................................................................41
9. REFERENCES...................................................................................................................43
Appendix A – Study Brief
Appendix B –Questionnaire sent to Manufacturers
Appendix C –Responses from Manufacturers
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Executive SummaryExecutive SummaryExecutive SummaryExecutive Summary
PB Power was commissioned by the DTI to identify new or emerging technologies that
would have the potential to allow increased levels of distributed generation to be
connected to the network up to 2010. The review covered primary and secondary
plant infrastructure, communications and IT.
The work was carried out in two stages. The first stage comprised literature searches,
internet searches, discussions with manufacturers and research institutions, as well as
information gathering from PB Power specialists. This information gathering stage
was a world wide review to identify significant R&D activities and products which may
be applicable to the UK distribution system. In addition, any overseas practices which
may be beneficial to the UK system were also identified.
Interviews were undertaken with four manufacturers and one university in order to
gain a better understanding of their R&D activities, identify any research gaps and find
any barriers to the development of systems necessary to allow the connection of
distributed generation.
The second stage of work reviewed all of the data collected during the first stage. The
results were classified by technology and rated according to their ability to allow the
connection of additional generation. The likely benefits and timescales for
implementation of each technology were also provided. Cost data has not been
presented due to the lack of data provided by the various manufacturers and
institutions.
The review identified that the technologies likely to have the most impact on the
connection of additional generation before 2010 were super-conducting fault current
limiters, in-line voltage regulators, micro-grid controllers and reactive power
compensators such as SVCs, FACTs and STATCOMs.
Super-conducting fault current limiters would allow the connection of generation into
networks where fault levels would otherwise be exceeded. In-line voltage regulators
have been demonstrated to allow additional generation to be connected by improving
the voltage regulation on the system. These are not widely used in the UK but are
considered to provide significant benefits. First generation micro-grid controllers will
soon be available which will provide a control interface between generators and the
primary substations to enable system voltages to be controlled more accurately.
Reactive power compensators have been used to allow the connection of distributed
generation but their application may be limited due to the relatively high unit cost.
A number of areas were identified where additional work may be required to remove
potential barriers to the connection of additional generation. The successful
connection and operation of large quantities of distributed generation will require a
high speed reliable communications network to be established. No standards were
identified which cover communications protocols between the substation and remote
devices on the distribution system.
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GlossaryGlossaryGlossaryGlossary
ACCC Aluminium Conductor Composite Core
ACSR Aluminium Core Steel Reinforced
AVC Automatic Voltage Control
CERTS Consortium for Electric Reliability Technology Solutions
CHP Combined Heat and Power
DC Direct Current
DCHP Domestic Combined Heat and Power
DFIG Doubly Fed Induction Generator
DG Distributed Generation
DNO Distribution Network Operator
DTI Department of Trade and Industry
EMS Energy Management System
ENA Electricity Networks Association
EPRI Electric Power Research Institute
EPSRC Engineering and Physical Sciences Research Council
ESQCR Electricity Safety, Quality and Continuity Regulations (2002)
FACTS Flexible Alternating Current Transmission System
FCL Fault Current Limiter
GTI Gas Technology Institute
HSE Health and Safety Executive
HTS High Temperature Superconductor
HV High Voltage
HVDC High Voltage Direct Current
IEE Institution of Electrical Engineers
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IEC International Electro technical Commission
ISDN Integrated Service Digital Network
IT Information Technology
MEMS Micro Electromechanical Systems
MVAr Mega Volt Amperes Reactive
MW Megawatts
NGC National Grid Company
NREL National Renewable Energy Laboratory
PLC Programmable Logic Controller
PV Photo Voltaic
R&D Research and Development
RTU Remote Terminal Unit
SCADA Supervisory Control And Data Acquisition
STACOM STATic COMpensator
SVC Static Var Compensator
TCP-IP Transmission Control Protocol - Internet Protocol
UI Universal Interface
VAR Volt Amperes Reactive
XLPE Cross Linked Polyethylene
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1.1.1.1. INTRODUCTIONINTRODUCTIONINTRODUCTIONINTRODUCTION
PB Power was commissioned by Future Energy Solutions, acting on behalf of the DTI,
to undertake a study into new distribution technologies.
The scope of the study was intended to identify new or emerging technologies that
would have the potential to allow increased levels of distributed generation to be
connected to the network, as detailed in the study brief contained in Appendix A. The
technologies to be covered included: -
• Primary and secondary plant infrastructure including
o Switchgear
o Transformers
o Overhead lines and cables
o SVCs, FACTs devices etc
o Fault current limiters
• SCADA systems including
o Telecommunications
o IT
o Substation automation
Only network related technologies have been covered, generation related technologies
have been omitted except where they form part of a wider system, for example in a
microgrid system.
All the technologies investigated were to have the potential to be commercially viable
or cost effective by 2010. Any technologies that were in use elsewhere in the world
have been included, technologies already in use in the UK have been largely excluded.
The study has been undertaken by investigating a number of sources as follows: -
• Literature review
• Internet searches
• Discussions with other PB Power Specialists
• Questionnaires and interviews with manufacturers
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References to published material and websites are provided at the end of this report.
The manufacturers’ questionnaire is presented in Appendix B whilst written responses
are contained in Appendix C.
The results of the research have been classified into different functional groups to aid
comparison between similar technologies. The potential advantages and
disadvantages have been identified, as well as timescales for availability and benefits
where available. Costs have not been included in this study as none were available for
products in development and few were provided for products currently available. PB
Power did, however, take a view on which technologies were likely to be commercially
available and cost-effective by 2010, based on the published literature and the
interviews with manufacturers.
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2.2.2.2. STUDY METHODOLOGYSTUDY METHODOLOGYSTUDY METHODOLOGYSTUDY METHODOLOGY
2.12.12.12.1 Literature SearchesLiterature SearchesLiterature SearchesLiterature Searches
The literature searches were based on three sources: -
• Public domain material identified in the project scope
• Public domain material currently held by PB Power
• Public domain material obtained from the internet searches
The documents obtained were checked for references to new technologies as well as
manufacturers, research programmes and references to other work. Useful references
were then followed up to increase the spread of the search.
Colleagues within PB Power and Parsons Brinckerhoff in the US, UK and Australia
were contacted to identify new technologies and also existing technologies employed
outside of the UK.
2.22.22.22.2 Internet SearchesInternet SearchesInternet SearchesInternet Searches
A number of search techniques were utilised to identify potential material for input to
the literature searches and manufacturers questionnaires. These included: -
• Internet search engines
• Manufacturers’ web sites
• The IEE Discussion Forums
The results of the internet searches led to literature reviews, further internet searches
as well as providing more detailed information on manufacturers, their products and
R&D activities.
2.32.32.32.3 Questionnaires and InterviewsQuestionnaires and InterviewsQuestionnaires and InterviewsQuestionnaires and Interviews
A list of manufacturers was compiled from the results of the literature and Internet
searches. Two questionnaires were then compiled as detailed in Appendix B. One
was sent to companies with a UK office and the second questionnaire was sent out to
companies with no UK offices.
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Where possible meetings were arranged to discuss the questionnaire, outline the
companies’ product development plans and determine the types of products that the
companies expected to develop and be in production before 2010. Meetings were
held with the following companies: -
• ABB
• AREVA
• Remsdaq
• Econnect
Discussions were also held with a variety of other companies and institutions that
were either developing or marketing distribution products. The data requested was
product dependent but included budget costs and product specifications. The results
of these enquiries are contained in Appendix C. The companies and institutions
contacted were as follows: -
• Eve Group Ltd (UK) / Composite Technology Corporation Inc (US)
• University of Canterbury (NZ) / CanterburyTX (NZ)
• Wilson Transformers (UK) / Dynamic Rating Equipment (AUS)
• American Superconductors
Approaches were also made to the following companies but at the time of writing the
report, no response had been received.
• Southwire
• Waukesha Electric
• Nexans
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3.3.3.3. INTERVIEWS AND QUESTINTERVIEWS AND QUESTINTERVIEWS AND QUESTINTERVIEWS AND QUESTIONNAIRESIONNAIRESIONNAIRESIONNAIRES
3.13.13.13.1 InterviewsInterviewsInterviewsInterviews
Interviews were conducted with four manufacturers to discuss their current R&D
programmes and products. Specific technology details have been documented in
sections 4 and 5 whilst the outcome of more general discussions is detailed below.
An interview was also conducted with Prof. N Jenkins and Prof. G Strbac of the
University of Manchester.
3.23.23.23.2 ABBABBABBABB
Discussions were held at ABB’s Stone offices on the 12 October 2004. ABB are
engaged in a wide range of R&D activities including: -
• Primary plant e.g. switchgear, transformers, circuit breakers, fuses and
cables etc
• FACTs technologies, including HVDC Light
• Insulation materials
• Test procedures
• Sensor technologies
• Materials technologies including nanotechnology
• SCADA and EMS systems
Due to the wide range of R&D activities undertaken by ABB, only those of most
relevance to increasing generation capacity on distribution systems have been
considered. These are described below and in sections 4 and 5.
• SVCs, FACTs and STATCOMs, detailed in section 4.4
• Switchgear and fault current limiters, detailed in section 4.5
• SCADA Systems and Substation Automation, detailed in section 5.2
• Nanotechnology
o ABB is working in partnership with the Rensselaer Nanotechnology
Institute in New York to develop improvements in materials
technologies. It is envisaged that this will produce materials with
improved mechanical and electrical properties giving lower losses,
enhanced insulation characteristics, improved electromagnetic
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performance as well as giving cost and weight savings. No details
were provided in relation to potential products, production dates or
costs.
• Microelectromechanical Systems (MEMS)
o ABB is working in partnership with three overseas institutions to
develop MEMS for sensors and instrumentation based on integrated
circuit technology. No specific applications were provided although
the technology is expected to benefit the power industry. No details
were provided in relation to potential products, production dates or
costs.
A number of other issues were discussed and these are summarised below: -
• The lead-time from the inception of a research or development project to
the availability of a commercial product can be 10 years or more. The
development of a new product would have to be at an advanced stage now
in order for it to be available before 2010.
• Research is generally market led. If a market cannot be identified then there
is little chance of undertaking any required R&D. Some form of feedback
from network operators is therefore required in order to identify potential
markets and needs early enough to allow products to be developed.
• Any requirement to comply with UK-specific standards (e.g. ENAs Technical
Specifications) as opposed to international IEC standards increases
production costs and reduces the scope for product development.
3.33.33.33.3 AREAREAREAREVAVAVAVA
Discussions were held at AREVA’s Stafford offices on the 13th October 2004. AREVA’s
current R&D activities of interest to this study are described in sections 4, 5 and other
issues are described below: -
• As with ABB, the R&D activities are generally market led. Both AREVA and
ABB stated that with no clear indication of the future of the distribution
systems, it was difficult to identify market needs.
• Any requirement for UK specific standards was also considered to raise
issues with regard to global product development.
3.43.43.43.4 EconnectEconnectEconnectEconnect
Discussions were held at Econnect’s Hexham offices on the 20 October 2004.
Econnect’s current R&D activities of interest are described in sections 4 and 5.
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3.53.53.53.5 RemsdaqRemsdaqRemsdaqRemsdaq
Discussions were held with Remsdaq at PB Power’s Manchester offices on the 7
October 2004. Remsdaq’s current R&D activities of interest are described in sections 4
and 5.
3.63.63.63.6 University of ManchesterUniversity of ManchesterUniversity of ManchesterUniversity of Manchester
Discussions were held with Prof. N Jenkins and Prof. G Strbac at the University of
Manchester on the 15 November 2004. The results of these discussions are contained
in sections 4 and 5 with other general issues described below: -
• The requirement for energy storage system was not considered to be
necessary before 2010, due to insufficient levels of wind generation and
high costs making the technology prohibitively expensive, and suitable for
only the most valuable loads.
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4.4.4.4. PRIMARY PLANT TECHNOPRIMARY PLANT TECHNOPRIMARY PLANT TECHNOPRIMARY PLANT TECHNOLOGIESLOGIESLOGIESLOGIES
4.14.14.14.1 IntroductionIntroductionIntroductionIntroduction
This section presents the results and analysis of the various searches for new
technologies applicable to primary plant.
The primary plant technologies have been classified under the following groups: -
• Transformers
• Overhead lines and cables
• SVCs, FACTs and STATCOMs
• Switchgear and Fault Current Limiters
The results of the research for each group are presented in the following sections.
Generation related technologies have been excluded from these studies.
The range of equipment considered is from 240V up to and including 132kV.
4.24.24.24.2 TransformersTransformersTransformersTransformers
The main area of R&D for transformer design is in the development of
superconducting windings. These utilise high temperature superconducting (HTS)
material cooled by affordable liquid nitrogen.
4.2.14.2.14.2.14.2.1 DevelopmentsDevelopmentsDevelopmentsDevelopments
4.2.1.14.2.1.14.2.1.14.2.1.1 AREVAAREVAAREVAAREVA
AREVA is currently developing several new transformer technologies. Solid-state tap
changers are under development. These could be retrofitted to existing transformers
or could be fitted to new transformers. The main advantage could be the improved
reliability and lower maintenance requirements over existing mechanical devices. It is
expected that the tap changers would have full reverse power capability.
A two-position tap changer is also being developed for smaller distribution
transformers. This would give an increased range of operation by providing low/high
load positions, winter/ summer or load/generation positions. It was not disclosed
whether these could be retrofitted to existing transformers with off-load or fixed taps.
No details of the tap step size were provided. A large step size may restrict operation
in order to comply with Engineering Recommendation P28.
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4.2.1.24.2.1.24.2.1.24.2.1.2 Other Companies and InstitutionsOther Companies and InstitutionsOther Companies and InstitutionsOther Companies and Institutions
The EPSRC SuperGen Initiative1 claims limited benefits from superconducting
transformers. The main benefits are from the reduced size and reduced
environmental hazards. Due to the high efficiency of conventional transformers the
reduced losses of HTS transformers are not considered a major advantage.
The University of Canterbury (NZ) is in the process of developing an HTS transformer
in conjunction with CanterburyTX2. A resonating high voltage transformer has already
been constructed and utilised for testing other HV transformers. Advantages of the
HTS transformer are the use of liquid nitrogen as both a coolant for the HTS windings
and as a dielectric as opposed to oil. This reduces the environmental hazards and fire
risks. A special core design substantially reduces stray electric and magnetic fields,
thereby reducing interference with other equipment. The current carrying capacity is
higher, meaning that a HTS transformer could have four times the rating of a
conventional identically sized transformer. Voltage regulation is improved due to the
lower leakage reactance reducing the requirement for a tap changer. Fault levels
would be increased however. No cost indications or expected manufacturing dates
have been given.
Waukesha Electric Systems (US)3 is also developing an HTS transformer in its
dedicated R&D facility. Few details are given other than the perceived benefits of
reduced size and weight, no environmental or fire safety hazards, extended lifetime,
greater efficiency and 100% continuous overload capability. No cost indications or
expected manufacturing dates have been given.
SF6 insulated transformers are currently available from Mitsubishi Electric Ltd4. They
are available over a voltage range of 11kV to 33kV with a reduced footprint compared
to conventional dry-type transformers.
Dynamic Ratings (AUS)5 has developed dynamic transformer rating equipment that
provides the ability to utilise the full overload capability of the transformer. Optical
fibre temperature measurement is employed to determine the winding temperature
and provide an input to the dynamic rating and insulation ageing software. The
system provides transformer load monitoring and control, although the method of
controlling the load is not stated. A full system replaces all existing transformer
control equipment, including the AVC control and the pump and fan controls. It can
be fitted to new transformers or retro- fitted to existing transformers. Development
work is being undertaken on more advanced equipment. Existing products have
recently been installed on transformers on the Kansas City system in the US and a few
transformers in the UK. Although the technology is not new to the UK, it is not in
widespread use. It is being marketed in the UK by Wilson Transformers Ltd, an
Australian manufacturer.
Cooper Industries6 manufacture in-line voltage regulators for 2.4kV to 34.5kV systems.
These provide a 32 step ±10% tap range with ratings between 33kVA and 1MVA in
both directions. They are placed in series on a distribution circuit and provide
accurate voltage regulation of the downstream circuit section. These devices have
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been used by SP Powersystems in North Wales to allow increased amounts of
generation to be installed. They have also been installed by Scottish Hydro on the
11kV and 33kV systems, mainly to control the voltage profile on long circuits. They
have also been used to allow generation to be connected although problems were
experienced when loads and generators were connected onto the same circuit. For
this reason small SVCs are now being installed where required. They have been
included in this report as their use in the UK is not thought to be widespread. In-line
voltage regulators are in more common use in both Northern Ireland and the Republic
of Ireland where loads may be sparser than in Great Britain. Guidance on their use is
provided in ETR 126 ‘Guidelines for Actively Managing Voltage Levels Associated with
the Connection of a Single Distributed Generation Plant’7.
4.2.24.2.24.2.24.2.2 ReviewReviewReviewReview
HTS transformers are currently being developed by a number of companies and
institutions. They have a significantly higher power rating for the same footprint as a
conventional oil-filled or cast resin transformer. This may avoid the need to relocate
existing substations or build additional substations to accommodate load growth.
Fewer substations could therefore supply a wider area or increased load transfers
could be accommodated at lower voltage levels. Lower environmental hazards would
be realised due to the use of liquid nitrogen as opposed to oil, minimising fire risks
and disposal issues.
There would be less requirement for a tap changer on an HTS transformer due to the
lower reactances resulting in a low voltage drop. This would improve reliability by
reducing the maintenance but would also increase fault levels.
Disadvantages envisaged are more expensive cooling arrangements and higher plant
costs due to the use of superconducting materials. Integration into the existing
system would be relatively easy due to the smaller footprint of the transformers,
though space would be required for the cooling equipment. This equipment could
however be common to a number of HTS transformers, cables and other plant such as
fault current limiters (FCLs).
All these developments would allow space to be made available at existing
substations to accommodate additional switchgear or control equipment.
Dynamic transformer rating equipment is currently available and in service on
transformers between 50MVA and 333MVA, allowing closer control of the maximum
transformer load than at present and a possible means of postponing reinforcement
requirements. Potentially dynamic loading could increase the allowable loading by
10% to 20%. This figure would be dependent on ambient temperature, cooling
efficiency and previous loading conditions. Dynamic loading could also reduce the
allowable maximum loading under adverse conditions although under these
circumstances remedial action such as load shedding might be required.
In-line voltage regulators have been shown to allow the connection of additional
generation but are not thought to be widely used in Great Britain.
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4.2.34.2.34.2.34.2.3 SummarySummarySummarySummary
The following table summarises the features of the transformer technologies.
ManufacturerManufacturerManufacturerManufacturer Product or Product or Product or Product or
TechnologyTechnologyTechnologyTechnology AvailabilityAvailabilityAvailabilityAvailability Advantages/DisadvantagesAdvantages/DisadvantagesAdvantages/DisadvantagesAdvantages/Disadvantages
Solid State Tap Changer
Under development
No tap wear allowing increased frequency of operation and ‘faster’ voltage control. Full reverse power capability.
AREVA
Two Position Tap Changer
Under development
Provides low/high load or load/generation positions for greater operational flexibility.
CanterburyTX Superconducting Power Transformers
Under development
Lower losses, smaller footprint, no oil required, and high overload capability.
More expensive cooling arrangements.
Tap changer requirements reduced. Possibility of low maintenance but higher fault levels.
Waukesha Electric Systems
Superconducting Power Transformers
Under development
Lower losses, smaller footprint, no oil required, and high overload capability.
More expensive cooling arrangements.
Tap changer requirements reduced. Possibility of low maintenance but higher fault levels.
Dynamic Ratings
Dynamic Rating Equipment
In use
Allows potentially higher loadings to be carried. Insulation ageing calculations also provided. Maximum loading dependent on environmental factors plus previous loading.
Cooper Industries
In-line Voltage Regulators
In use Regulate distribution system voltages, reverse power capability. In very limited use in Great Britain.
Mitsubishi Electric Ltd
SF6 Distribution Transformers
In use Smaller footprint than dry-type transformers.
4.34.34.34.3 Overhead Lines and CablesOverhead Lines and CablesOverhead Lines and CablesOverhead Lines and Cables
4.3.14.3.14.3.14.3.1 DevelopmentsDevelopmentsDevelopmentsDevelopments
Superconductivity is also the main area of development for power cables. J. W. Ekin8
of the National Institute of Standards and Technology, Boulder, Colorado states that
three superconducting cable projects are under construction in the US. The largest is
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a 600m, 2400A, 138kV cable being constructed by Nexans and American
Superconductor for the Long Island Power Authority, New York. This is due to be
energised by 2006. A three to seven fold increase in current carrying capacity is given
for an HTS cable over a conventional identically sized copper cable. Cables are of
hollow single core, coaxial or triaxial construction. Ohmic resistance (and losses)
would be decreased which may increase fault levels.
The EPSRC SuperGen Initiative1 claims limited benefits from superconducting cables.
They would reduce the resistive transmission losses but the high costs and inefficient
cooling would make such cables non-competitive compared to conventional
underground cables or overhead lines. There may, however, be an application in
congested urban areas where the higher power densities would allow greater power
transfer along existing cable routes.
Systems that monitor cable core temperature using optical fibres or thermocouples in
order to provide a dynamic current rating are available from KEMA9. Thermocouples
are fitted to existing cables where optical fibres are not available. This is carried out on
a consultancy basis on selected cables. Mathematical modelling is undertaken to
determine the cable performance under dynamic loading conditions and to provide
information on insulation ageing. The Belgian transmission system owner, ELIA, has
installed this system on a 150kV cable circuit in Brussels. Real time temperature data
and overload capabilities can be accessed to allow greater operational flexibility10.
NGC are installing similar technology on the new 400kV, 20km cable between Elstree
and St Johns Wood11. Two optical fibres are built into the cable to provide continuous
temperature monitoring.
There are also developments in overhead line technology. Gap type conductors
incorporate an annular gap between the steel core and the outer aluminium strands.
The conductor is suspended by tensioning the steel core with the aluminium strands
left slack. The conductor sag is therefore a function of the expansion of the steel core.
Higher stringing tensions give lower sags which allow higher currents to be carried.
These conductors are being installed by NGC to uprate existing circuits.
A new overhead line conductor has been developed which is claimed to provide a 1.6
increase over conventional ACSR conductors12. In order to reduce the sag and provide
higher ratings a conventional ACSR conductor is constructed with a pre-tensioned
steel core. After the conductor has been constructed the tension is released in the
steel core which causes the aluminium strands to slacken. During operation the steel
core expands and takes up the slack in the aluminium conductor. This results in a
lower sag and higher power rating. Conventional installation techniques are used
which removes the need for the tower reinforcement that may be required when using
gap type conductors. The new conductor has been used on 34 lines in Japan.
Composite Technology Corporation (US) is producing an ACCC (Aluminium Conductor
Composite Core) conductor that utilises a composite core in place of a steel or
aluminium core13. The first commercial installation was completed in August 2004.
The low thermal expansion coefficient of the core results in lower conductor sag and
Page 13
thereby allows higher operating temperatures. No special installation techniques are
required. The rating given for an ACCC conductor is 1902A compared to 905A for the
same size Drake conductor (approx 400mm2 ACSR). The allowable operating
temperature is increased from 75°C up to 200°C. Details of the discussions with the
UK representative are given in Appendix C.
4.3.24.3.24.3.24.3.2 ReviewReviewReviewReview
Development activities for HTS cables have to date concentrated on the higher voltage
levels and therefore it is envisaged that HTS cables would be most applicable to high
voltage distribution (132kV) initially. Existing urban cable routes could be upgraded
from conventional paper insulated cable to HTS cable giving an increased capacity in
congested cable corridors. It is possible that the technology could be applied in the
future since the 132kV cables currently installed can be short lengths from a terminal
tower to a nearby substation. The additional cost of HTS cables may not provide
sufficient benefits to the DNOs, as old or overloaded circuits could be upgraded using
suitably rated XLPE cables. The cost may also limit the application of HTS cables to
higher voltage levels.
Dynamic conductor monitoring systems are currently available and are in use in
Belgium. They have enabling increased current carrying capability by allowing cable
hot spots to be identified and rectified. The system requires that the monitored cables
are fitted with optical fibres and this may limit the number of applications. An
alternative would be to incorporate temperature measuring fibres during manufacture
although no manufacturers appear to have plans for this.
Composite overhead conductors are currently available and have been installed at a
number of locations. It is envisaged that they have the potential to increase the
capacity of overhead lines by simply replacing existing conductors using conventional
installation techniques and equipment. Composite conductors could be applied at any
voltage level thereby assisting in the relief of bottlenecks, increasing transfer
capacities and allowing increased loads and generation to be connected.
The limitations of the North – South transmission inter-connector may constrain the
connection of new wind generation in Scotland.
4.3.34.3.34.3.34.3.3 SummarySummarySummarySummary
The following table summarises the features of the cable and conductor technologies.
ManufacturerManufacturerManufacturerManufacturer Product or Product or Product or Product or
TechnologyTechnologyTechnologyTechnology AvailabilityAvailabilityAvailabilityAvailability Advantages/DisadvantagesAdvantages/DisadvantagesAdvantages/DisadvantagesAdvantages/Disadvantages
Nexans Superconducting Power Cables
Under trial in several installations
Lower losses, higher capacity for similar sized cables. Higher fault levels.
More expensive cooling arrangements (compared to oil/gas filled cables).
Page 14
ManufacturerManufacturerManufacturerManufacturer Product or Product or Product or Product or
TechnologyTechnologyTechnologyTechnology AvailabilityAvailabilityAvailabilityAvailability Advantages/DisadvantagesAdvantages/DisadvantagesAdvantages/DisadvantagesAdvantages/Disadvantages
KEMA Dynamic Cable Rating Equipment
In use
May not provide significant increase in capacity, requires thermocouples to be fitted to existing cables or installation of new cables. Could be employed on future cables if manufacturers incorporate optical fibre temperature measurement into cables.
Composite Technology Corporation
Composite Overhead Conductors
In use
Higher capacity for similar sized conductor, no special installations requirements, equally applicable at any voltage level.
4.44.44.44.4 SVCs, FACTs and STATCOMsSVCs, FACTs and STATCOMsSVCs, FACTs and STATCOMsSVCs, FACTs and STATCOMs
4.4.14.4.14.4.14.4.1 DevelopmentsDevelopmentsDevelopmentsDevelopments
4.4.1.14.4.1.14.4.1.14.4.1.1 ABBABBABBABB
ABB currently produce FACTS and HVDC Light devices for high voltage transmission
and distribution solutions. ABB is not developing similar devices for use at
distribution voltage levels of 33kV and below as the company does not believe there is
sufficient demand and the relatively high costs would present a significant barrier to
their deployment.
The ABB HVDC Light system provides a DC link of up to 100MW between two remote
AC systems. This has been employed to connect a remote wind farm to the
transmission system in Gottland, Sweden. The cable link is 70km long with a rating of
50MW at 80kV. A DC link was selected due to the difficultly in building a new
transmission line as well as the ability of the system to improve power quality.
4.4.1.24.4.1.24.4.1.24.4.1.2 AREVAAREVAAREVAAREVA
AREVA is in the final stages of developing a compact STATCOM, C-STATCOM. The
first equipment is scheduled to go into service at the end of 2005. A single C-
STATCOM cabin has a steady state rating of ±10MVAr and up to five modules may be
combined to give ±50MVAr. The cabins will normally be connected to the power
system via a tertiary transformer winding. Connection voltages are expected to range
from 11kV to 132kV. The reactive power capability provides extremely fast voltage
control improving voltage regulation, flicker and power quality. They can also reduce
post fault oscillations and improve the ability to ride through faults. The addition of
energy storage provides full four quadrant operation. The required output is
maintained over a very wide voltage range whilst the dynamic capability of each
module is twice the steady state rating.
AREVA is also developing a new common range of SVCs that will be available for
tendering at the beginning of the second quarter of 2005. These provide similar
Page 15
benefits to STATCOMs; however, the STATCOM has some superior characteristics
whilst SVCs provide a lower cost solution.
4.4.1.34.4.1.34.4.1.34.4.1.3 Other Companies and InstitutionsOther Companies and InstitutionsOther Companies and InstitutionsOther Companies and Institutions
American Superconductors14 manufacture a range of static and rotary power systems
devices which are described below: -
• D-VAR – Dynamic VAR system similar to a STATCOM. Provides an
‘instantaneous’, continuous source of reactive power. Can be used to resolve
voltage stability issues, increase transfer capabilities, minimise voltage flicker,
improve fault ride through and improve steady state voltage regulation.
Already in use providing up to –37 to 97MVAr of reactive power mainly in the
US. Operates over 480V to 35kV with outputs of 1.0 to 8.0MVAr.
• SuperVAR – an HTS synchronous condenser. Due to the use of an HTS field
winding the unit is more efficient, compact and reliable compared to
conventional synchronous condensers. A ±10MVAr, 13.8kV unit is available
with maintenance costs of <$10k per annum. It provides steady state voltage
regulation, increases system inertia, responds to system transients and
generates no harmonic currents. It also provides a fault level contribution. The
transient rating is up to 8.0pu.
• D-SMES – Distributed Superconducting Magnetic Energy Storage system. Can
inject real and reactive power into the system, up to 3MW and 8MVAr
(18.4MVAR instantaneous) per unit. Fast response provides benefits during
voltage collapse and instability on systems between 69-500kV. The ability to
inject real power into the network may allow generators to ride through more
severe faults or provide a smoother transition to and from island mode
operation.
Scottish Hydro have installed SVCs at the distribution level in order to improve the
voltage control when generators are connected to the system. These are being
installed where in-line voltage regulators do not provide a wide enough range of
operation to accommodate the opposing demands of load and generation.
4.4.24.4.24.4.24.4.2 ReviewReviewReviewReview
FACTs technologies provide the opportunity to provide both steady state and dynamic
voltage support for a range of voltages and power levels. Power quality can be
enhanced and the reactive power capabilities could be utilised to reduce network
losses. The dynamic response could provide additional inertia or MVAr/voltage
support to reduce the effect of faults on local generators.
A variety of STATCOM products are available or due to go into production before
2010. These would provide improved steady state and dynamic voltage support for
the network. Some manufacturers provide the facility for injecting real power into the
network to improve the fault ride through characteristics.
Page 16
Distribution voltage SVCs are being installed by one DNO to overcome the limitations
of in-line voltage regulators.
4.4.34.4.34.4.34.4.3 SummarySummarySummarySummary
The following table summarises the features of the transformer technologies.
ManufacturerManufacturerManufacturerManufacturer Product or Product or Product or Product or
TechnologyTechnologyTechnologyTechnology AvailabilityAvailabilityAvailabilityAvailability Advantages/DisadvantagesAdvantages/DisadvantagesAdvantages/DisadvantagesAdvantages/Disadvantages
ABB FACTS, HVDC Light, SVC
In use Provides steady state and dynamic MVAr capability reducing flicker, improving stability and regulation.
AREVA C-STATCOM Q4 2005
Improves system voltage regulation, provides steady state and dynamic reactive capability. Energy storage capability for four quadrant operation.
D-VAR (STATCOM) devices
In use Provides steady state and dynamic MVAr capability reducing flicker, improving stability and regulation.
SuperVAR HTS synchronous compensator
In use
Increases system inertia, no harmonic contribution, provides steady state regulation.
Increases system fault levels.
American Superconductors
D-SMES HTS Magnetic Energy Storage System
In use Provides real and reactive power injection during transients. Fast response.
4.54.54.54.5 Switchgear and Fault Current LimitersSwitchgear and Fault Current LimitersSwitchgear and Fault Current LimitersSwitchgear and Fault Current Limiters
4.5.14.5.14.5.14.5.1 DevelopmentsDevelopmentsDevelopmentsDevelopments
4.5.1.14.5.1.14.5.1.14.5.1.1 ABBABBABBABB
ABB is continuously developing its range of switchgear products, covering most
distribution voltages. The main area of innovation is considered to be the use of new
or alternative materials. This could lead to more compact cubicles allowing additional
circuits to be installed in existing substations. This may generate interface problems
with existing equipment such as the need to re-route the existing cables. There is also
a possibility that cubicle sizes will increase if the use of SF6 as an insulator is
discontinued due to environmental concerns.
One barrier to the use of a manufacturer’s standard design equipment in the UK is the
requirement for UK specific Energy Networks Association Switchgear Assessment
Panel approval in addition to the internationally recognised standards. The UK-
specific requirements largely stem from the need to meet the requirements of the
Page 17
ESQCR and the Distribution Code. For example UK equipment typically has more
comprehensive interlocking than continental equipment. DNOs are however
purchasing larger quantities of switchgear from continental manufacturers.
An 11kV solid state circuit breaker has been developed and is installed at a substation
in Switzerland. It is expected that these would operate faster than conventional circuit
breakers. It has not reached the commercialisation state yet due to various issues
including the cooling requirements and cost of the unit.
An intelligent vacuum circuit breaker has been developed for medium voltage
applications. This incorporates all the measurement, protection and control functions
into the circuit breaker truck reducing the cabling required as well as providing an
Internet communications interface. This would allow control and monitoring via a
wide area corporate network or an Internet connection. The smaller size and reduced
number of parts allows space and cost savings. This would allow extra circuits to be
incorporated into existing substations whilst simplifying the installation requirements.
4.5.1.24.5.1.24.5.1.24.5.1.2 AREVAAREVAAREVAAREVA
A magnetic type fault current limiter has been developed. The prototype working
voltage ranges will be between 3.5kV and 33kV.
4.5.1.34.5.1.34.5.1.34.5.1.3 Other Companies and InstitutionsOther Companies and InstitutionsOther Companies and InstitutionsOther Companies and Institutions
Nexans15 have recently installed a 10MVA capacity HTS fault current limiter (FCL) on
an RWE 10kV network in Germany in May 2004. The next stage of development is for
a 110kV unit. HTS FCLs exhibit rapid resistance or reactance changes above defined
current limits. Excessive current levels force a change of state from superconducting
to resistive which results in a lower fault current. Conventional circuit breakers and
protection relays can then be used to isolate the faulted equipment.
EPRI is sponsoring a project16 to demonstrate an HTS FCL suitable for use on a 138kV
transmission network. The beta test version, currently being developed by Nexans, is
scheduled for installation in 2006 and will then undergo a one to two year test phase.
The EPSRC SuperGen Initiaitive1 anticipates that the first superconducting application
will be for fault current limiters that should be commercially available within 5 years.
They react more rapidly than any circuit breakers and are regarded as essential to
enable the incorporation of distributed generation into the grid system.
4.5.24.5.24.5.24.5.2 ReviewReviewReviewReview
Increased levels of distributed generation will typically result in increased system fault
levels. Fault current limiters could be employed to reduce the need to upgrade
switchgear fault ratings, and possibly allow the use of lower rated equipment in order
to reduce costs. It is considered that they could make a significant contribution to
allowing increased generation because of their ability to effectively split the network
or control fault flows.
Page 18
The future generation of fault current limiters will be fail-safe. HTS FCLs are inherently
fail-safe since the collapse of superconductivity is directly related to the current
density. No external systems are required to initiate operation, indeed failure of an
external system, such as the cooling, causes the FCL to operate.
Development is in the advanced stages with several prototypes in use at various
voltage levels. It is expected that these devices would be available by 2010.
Installation of a FCL could avoid the requirement to replace entire switchboards,
thereby reducing reinforcement costs.
An intelligent 11kV circuit breaker has been developed which incorporates all the
monitoring, control and protection functions inside the circuit breaker truck. All
functions are available via an Internet type interface which reduces installation costs.
New materials technologies are expected to provide smaller switchgear components
due to improvements in insulation properties. This may allow more equipment to be
installed in existing substations.
4.5.34.5.34.5.34.5.3 SummarySummarySummarySummary
The following table summarises the features of the FCL technologies.
ManufacturerManufacturerManufacturerManufacturer Product or Product or Product or Product or
TechnologyTechnologyTechnologyTechnology AvailabilityAvailabilityAvailabilityAvailability Advantages/DisadvantagesAdvantages/DisadvantagesAdvantages/DisadvantagesAdvantages/Disadvantages
Switchgear Improvements based on new materials technologies
Not given Smaller cubicle sizes, therefore more feeders per substation
Medium Voltage Intelligent VCB
Now
Incorporates measurement, protection and control functions into circuit breaker truck. Control and monitoring via internet interface.
ABB
Solid State Circuit Breaker
Not given Faster operation and reduced maintenance
AREVA Superconducting Fault Current Limiters
Under development
Failsafe operation, allows system operation at higher fault levels. Can avoid the need for asset replacement. Allows increased levels of generation to be connected.
Page 19
ManufacturerManufacturerManufacturerManufacturer Product or Product or Product or Product or
TechnologyTechnologyTechnologyTechnology AvailabilityAvailabilityAvailabilityAvailability Advantages/DisadvantagesAdvantages/DisadvantagesAdvantages/DisadvantagesAdvantages/Disadvantages
Magnetic Fault Current Limiter
Under development
Allows system operation at higher fault levels. Can avoid the need for asset replacement. Allows increased levels of generation to be connected.
Fail safe operation.
Nexans Superconducting Fault Current Limiters
Under trial in several installations
Failsafe operation, allows system operation at higher fault levels. Can avoid the need for asset replacement. Allows increased levels of generation to be connected.
Page 20
5.5.5.5. SECONDARY PLANT TECHSECONDARY PLANT TECHSECONDARY PLANT TECHSECONDARY PLANT TECHNOLOGIESNOLOGIESNOLOGIESNOLOGIES
5.15.15.15.1 IntroductionIntroductionIntroductionIntroduction
This section presents the results and analysis of the various searches for new
technologies applicable to secondary plant.
The technologies covered by secondary plant technologies include: -
• SCADA Systems and Substation Automation
• Communications Systems
Generation related technologies have been excluded from these studies except where
they form part of a wider system.
5.25.25.25.2 SCADA Systems and Substation AutomationSCADA Systems and Substation AutomationSCADA Systems and Substation AutomationSCADA Systems and Substation Automation
5.2.15.2.15.2.15.2.1 DevelopmentsDevelopmentsDevelopmentsDevelopments
5.2.1.15.2.1.15.2.1.15.2.1.1 ABBABBABBABB
ABB17 have developed a range of SCADA software and automation equipment which
is currently available and in use around the world. Advanced features are readily
available which allow a fully integrated network management system to be developed.
Optional functionality includes outage management, network planning, optimal power
flow and reliability analysis. Future developments include the integration of real time
software for energy trading whilst Internet technology is used to allow operation from
a wide range of devices.
The range of equipment varies from large centralised SCADA systems to distributed
units for individual substations. Although the equipment is already is use in the UK it
is not thought by the manufacturers that the full capabilities of the various systems are
used. This may be due to the network operators not purchasing the additional
features or not having suitably qualified engineers to take advantage of the increased
functionality. It was considered that developing countries often made better use of the
advanced product features in place of installing additional substation equipment.
5.2.1.25.2.1.25.2.1.25.2.1.2 AREVAAREVAAREVAAREVA
AREVA are developing the next generation SCADA and Energy Management
Applications incorporating the specific DER requirements under its e-terra platform.
This is a modularised and fully integrated, object orientated system which
incorporates a wide range of advanced features such as market trading interface, wind
farm prediction and optimal Voltage-VAR Control schemes.
The system will, when complete, allow direct control of all system devices from circuit
breakers to individual wind turbines and FACTS devices. The software incorporates
Page 21
the required protocol interface to each individual device, employing standard state of
the Art Ethernet TCP-IP OPC and IEC61850 based protocols.
Control is provided at all levels, from individual generator controls, control of a
specific area to system wide voltage and power controls. These controls range from
simple open/close to more sophisticated coordinated distributed MW or MVAR control
schemes incorporatingtap changers, DFIG, Statcom, Micro CHP, and any controllable
loads.. Any type of device could be incorporated into the system providing it had a
suitable interface. This includes any wind turbines or other generators such as PV,
micro CHP etc.
The system operates over a fast Ethernet 100Mbit./s communications network with
peer to peer communication between devices to achieve fast automation within the
plant. The system is also open to include extra software applications required for any
commercially driven control required in the future (for example reactive power
ancillary services).
5.2.1.35.2.1.35.2.1.35.2.1.3 EconnectEconnectEconnectEconnect
Econnect18 have developed a range of solutions to manage voltage rise issues that
allow increased levels of distributed generation to be connected. The principal system
is called GenAVC™ which is designed to improve the voltage regulation on
distribution systems incorporating generators. GenAVC™ works in conjunction with
standard automatic voltage control (AVC) relays on the tap changers of 33kV/ 11kV
(primary) transformers. State estimation software is run on an industrial pc platform
holding a model of the network and receiving inputs of real and reactive power flows
and voltages on all feeders connected to the primary substation, and also inputs of
power and voltage information at the DG site. Two sets of trials are currently
underway, one on a section of 11kV network in EDF Energy’s Eastern network, and one
on United Utilities Carlisle network. Each network contains a DG scheme. Econnect’s
studies indicate that GenAVC™ could double the amount of generation that could be
connected to a network. It is expected to be in production in approximately 12 months.
Other Econnect solutions for voltage rise issues include the GenV™ control system
that can control the MW and MVAr output of a generator to response to the network
voltage. GenV™ is most appropriate for smaller generation projects when the
probable occurrence of constraint conditions due to voltage rise is low.
Econnect’s established range of load controllers for autonomous operation on
islanded networks is being further developed to incorporate embedded
communications ability to control on-site loads. These loads may be controlled as
part of a voltage rise mitigation, or to maximise on-site usage of own generation,
displacing more expensive bought-in energy. These new products will be field tested
in early 2005, with a target for market readiness of September 2005. Both power line
carrier and low power radio communication options will be available to suit a wide
range of applications.
Page 22
5.2.1.45.2.1.45.2.1.45.2.1.4 RemsdaqRemsdaqRemsdaqRemsdaq
Remsdaq19 are currently marketing an advanced RTU system called CallistoIES which is
currently used by a number of UK utilities and generators. Briefly it provides various
control and monitoring functions for a variety of devices including interfaces to
capacitor banks and wind turbine control systems. Strictly this system is outside the
scope of this study since it is in use in the UK, however it has been included as an
example of existing technologies which could be further developed.
5.2.1.55.2.1.55.2.1.55.2.1.5 University of ManchesterUniversity of ManchesterUniversity of ManchesterUniversity of Manchester
It was considered that the installation of active network management systems would
require the development of more sophisticated software tools, both to provide real
time system operation and to allow the networks to be designed and studied by the
planning departments.
Additional research and development would be required on systems to automatically
dispatch distributed generation on a continuous basis in response to measured
system data. It is likely that active network systems would be autonomously
controlling discrete sections of networks and therefore robust algorithms would be
required. In addition software tools would be required for use by the DNOs and
developers in order to design and study such networks.
The university believes that large numbers of active networks may not be developed
or required before 2010 as there would be limited levels of generation at the lower
distribution voltages (11kV and below).
5.2.1.65.2.1.65.2.1.65.2.1.6 Other Companies aOther Companies aOther Companies aOther Companies and Institutionsnd Institutionsnd Institutionsnd Institutions
The reliability of the DNO’s existing SCADA equipment and communications networks
was seen as a significant barrier to the use of such systems for controlling more
sophisticated networks20. The speed of operation would also make existing
communications channels unsuitable for the control of large number of generators.
Page 23
A large number of research projects have been identified which are aiming to develop
intelligent micro-grid controllers. A micro-grid controller can be considered as an
advanced RTU which provides a common controller for a discrete section of
distribution network. Features vary but all systems essentially combine an interface to
the various generators, transducers, transformers etc and a controller, or series of
controllers, that co-ordinate the control of generation, local system voltages and
power flows. Some of the various projects are described below: -
• Reliable, Low Cost Distributed Generator/Utility System Interconnect21
Funded by the National Renewable Energy Laboratory (NREL) in conjunction
with GE and Puget Sound Systems. Project objectives are to develop a
standard-compliant generation and grid interconnect to overcome
interconnection barriers, allow reliable system operation and ‘achieve the full
value of distributed generation’. GE are developing a Universal Interconnect
(UI) to provide a standard interface between any plant item and the remainder
of the system. The project includes a micro-grid study from 2004 to test the UI
devices.
• Innovative Distributed Power Interconnection and Control Systems22
Funded by the NREL in conjunction with the Gas Technology Institute (GTI) and
Encorp Inc. Projective objectives are to develop key enabling technologies for
cost effective distributed generation interconnection products, software and
communications solutions by the end of 2005.
• Intelligent Solutions for Distributed Power Technology23
Funded by NREL in conjunction with Orion Engineering Corporation. Research
objectives are to demonstrate a neural network control system for managing
small distributed generation. Orion Engineering has developed a system called
the Distributed Energy Neural Network Integration System (DENNIS) that
effectively aggregates a number of small generators into a single larger virtual
generator. Control of the generator dispatch is based on real time electricity
prices, individual demand profiles, state of discharge of storage devices and
weather conditions (to modify demand data).
• Consortium for Electric Reliability Technology Solutions24 (CERTS)
CERTS is a group of research institutions, headed by the Lawrence Berkeley
National Laboratory, who are undertaking research on micro-grid solutions, as
well as other fields. To date research has focused mainly on micro-grid
modelling tools, dynamic generator characteristic and data collection. Field
trials of a three generator micro-grid installation are planned for 2004 to
validate the research findings. There do not appear to be any plans yet to
produce marketable products.
Page 24
5.2.25.2.25.2.25.2.2 ReviewReviewReviewReview
The reliability and speed of operation of existing SCADA systems and
communications networks are seen as barriers to the control and operation of large
quantities of distributed generation.
The main areas of R&D activities are based around micro-grid network controllers to
actively control a discrete section of distribution network. Simplified versions which
provide limited functionality are currently available and in use, both in the UK and
overseas. The next stage of development could provide ‘Plug and Play’ type
generation interfaces providing an standardised control, monitoring and metering
interconnection to the network. These would interface to micro-grid controllers that
co-ordinate the operation of all the plant on a section of network. Current
programmes indicate that such devices could be available after 2006.
Several SCADA/EMS systems are currently available that provide advanced
functionality. These integrate all the system components and make them accessible
via a database for control and monitoring purposes. Advanced features include wind
speed prediction, wind farm control, network voltage and MVAr control etc. Although
some of these systems are already in use in the UK the advanced features are not
widely used, if at all.
RTU devices are becoming more advanced and provide PLC type functionality. These
would allow greater integration and control of components connected to the
substation. They could implement all the lower level control and monitoring
functionality required for control of the local distribution system in response to higher
level control from a centralised system. Such devices are already being used in the
UK.
Intelligent generation controllers are under development which would provide a co-
ordinated voltage control system for distribution networks incorporating generators.
Optimal power flow routines would be built in to identify the best generator dispatch
based on system loading and predicted wind resources. The system could be used to
provide a localised control system responsible for real time network operation,
communicating at a high level with a centralised DNO control system.
Load controllers are being developed to implement automatic load shedding schemes
for weak and islanded networks. This system may not allow additional generation to
be added to a system.
Page 25
5.2.35.2.35.2.35.2.3 SummarySummarySummarySummary
The following table summarises the features of the SCADA and substation automation
technologies.
ManufacturerManufacturerManufacturerManufacturer Product or Product or Product or Product or
TechnologyTechnologyTechnologyTechnology AvailabilityAvailabilityAvailabilityAvailability Advantages/DisadvantagesAdvantages/DisadvantagesAdvantages/DisadvantagesAdvantages/Disadvantages
ABB SCADA, EMS Systems
In use
Fully integrated solutions with advanced functionality.
DNOs may only be using the basic product features.
AREVA e-terra SCADA/EMS
In use Fully integrated system allowing control over all system devices from individual generators to system wide power control.
Remsdaq CallistoIES In use
Wide variety of communications protocols and media. Interfaces with various plant items, both local and remote. Flexible inbuilt intelligence, possible to automatically schedule generation, change transformer taps etc.
GenAVC Approximately 12 months
Provides voltage set-point adjustment for systems with embedded generators. May double amount of generation that could be connected.
Econnect
Load Controller Approximately 10 months
Automatic control of loads to provide some voltage rise mitigation and/ or maximise on-site usage of energy/ minimum bought-in energy to provide economic benefit.
Range being extended to cover grid connected applications.
5.35.35.35.3 Communications SystemsCommunications SystemsCommunications SystemsCommunications Systems
5.3.15.3.15.3.15.3.1 DevelopmentsDevelopmentsDevelopmentsDevelopments
None of the searches have identified any major developments in communications
technology. This may be because the communications systems are not seen as a
barrier to implementing new technologies. Current products and research use
existing communications technologies such as Ethernet and similar. For example,
AREVA has carried out R&D on new Ethernet Hub technology, to extend Ethernet
100Mbit/s over WAN configurations, and site configurations similar to windfarms.
New products such as the Remsdaq CallistoIES 19 can communicate over a large
number of proprietary protocols (e.g. AREVA K series relays) using virtually any media
such as ISDN, optical fibres, microwave, radio or satellite links.
Page 26
A wide variety of communications technologies are currently available which can
provide high speed links over a number of media with varying ranges. Ethernet,
optical fibres and microwave links can provide secure high speed communications
channels. Radio links such as Bluetooth can provide short range links within
substations. Although communication links may be sparse in rural areas the range of
existing technologies is considered capable of providing adequate, fast and secure
links between distributed plant items.
Communications channels may need to be established between new and existing
plant in order to take advantage of the latest developments in automation and control
systems.
AREVA questioned whether the existing communications protocols are suitable for
use into the future. The communications protocols must be capable of handling the
wider range of devices that are expected to be connected to the distribution system.
The communications systems must also be capable of handling the larger amounts of
data in timescales that allow an adequate level of network control. It is envisaged that
all devices connected to the system would have to incorporate an industry standard
interface to eliminate compatibility problems between the DNOs and consumers’
equipment.
IEC61850, Communications Networks and Systems in Substations25 provides a
communications system for substation control, monitoring and protection functions. It
covers communications between all substation devices from intelligent circuit
breakers to non-conventional instrument transformers up to the bay level and station
level control functions. No IEC standard was identified which specified a
communications systems for devices outside the substation.
Existing SCADA communications networks are seen as a significant barrier to the
integration of large quantities of distributed generation, as detailed in section 5.2.1.6.
5.3.25.3.25.3.25.3.2 ReviewReviewReviewReview
No major communications related research projects or product developments were
identified during the various searches. Existing communications technologies are
being utilised in the development of new products and research activities. The
principal communications barrier is considered to be the physical installation of a
reliable, high speed network using existing technologies, in order to overcome the
limitation of existing systems.
The suitability of the existing communication protocols may need to be examined to
ensure compatibility between the DNOs and consumers’ equipment.
5.3.35.3.35.3.35.3.3 SummarySummarySummarySummary
No major R&D projects related to communications technologies have been identified.
Page 27
The main communications barrier to increasing generation is considered to be
upgrading the existing slow and unreliable SCADA communications networks with a
high speed reliable infrastructure.
Communications protocols may need to be revised to prevent incompatibility between
the wide range of new devices that may be connected to the system. IEC61850
provides a communications standard for all substation components but no standard
was identified to cover the communications required between the substation and
devices located elsewhere on the distribution system.
Page 28
6.6.6.6. PRIMARY PLANT RESULTPRIMARY PLANT RESULTPRIMARY PLANT RESULTPRIMARY PLANT RESULTS SUMMARYS SUMMARYS SUMMARYS SUMMARY
This sections details the manufacturers and their technologies with likely benefits from section 4 in tabular format. It should be
noted that the results column ‘Potential to Allow Increased Generation’ are subjective. Factors considered when determining the
potential are the ability to resolve voltage regulation, reverse power flow and fault level issues. Technologies which relieve system
bottlenecks have been classified as having a lower potential to allow additional generation to be connected. Perceived costs have
also been taken into consideration.
6.16.16.16.1 TransformersTransformersTransformersTransformers
ManufacturerManufacturerManufacturerManufacturer Product/ Product/ Product/ Product/
TechnologyTechnologyTechnologyTechnology
Potential to Potential to Potential to Potential to
AlloAlloAlloAllow w w w
Increased Increased Increased Increased
GenerationGenerationGenerationGeneration
Applicability Applicability Applicability Applicability
to UK to UK to UK to UK
NetworkNetworkNetworkNetwork
BenefitsBenefitsBenefitsBenefits Implementation Implementation Implementation Implementation
BarriersBarriersBarriersBarriers TimescalesTimescalesTimescalesTimescales
Solid State Tap Changer
Low Voltage range
not known
Lower maintenance, full
reverse power capability,
faster switching, more
frequent tap operation.
Under development Not known
AREVA
Two Position Tap Changer
Medium Voltage range
not known
Gives low/high load or
load/generation tap
positions to accommodate
increased load/generation.
Under development Not known
Page 29
ManufacturerManufacturerManufacturerManufacturer Product/ Product/ Product/ Product/
TechnologyTechnologyTechnologyTechnology
Potential to Potential to Potential to Potential to
AlloAlloAlloAllow w w w
Increased Increased Increased Increased
GenerationGenerationGenerationGeneration
Applicability Applicability Applicability Applicability
to UK to UK to UK to UK
NetworkNetworkNetworkNetwork
BenefitsBenefitsBenefitsBenefits Implementation Implementation Implementation Implementation
BarriersBarriersBarriersBarriers TimescalesTimescalesTimescalesTimescales
CanterburyTX Superconducting Power Transformers
Medium Voltage range
not known
Increased substation
capacities due to smaller
footprint.
Product under
development. Cost and
lead time to large scale
production.
Possibility of increased
fault levels.
Not known
Waukesha Electric Systems
Superconducting Power Transformers
Medium Voltage range
not known
Increased substation
capacities due to smaller
footprint.
Product under
development. Cost and
lead time to large scale
production.
Possibility of increased
fault levels.
Not known
Dynamic Ratings
Dynamic Rating Equipment
Low to
medium All
Allows transformers to be
operated closer to their
maximum ratings
Minimal Available now
Cooper Industries
In-line Voltage Regulators
High 2.4kV to
34.5kV
Improved voltage
regulation of distribution
circuits. Reverse power
capability.
None Available now
Page 30
ManufacturerManufacturerManufacturerManufacturer Product/ Product/ Product/ Product/
TechnologyTechnologyTechnologyTechnology
Potential to Potential to Potential to Potential to
AlloAlloAlloAllow w w w
Increased Increased Increased Increased
GenerationGenerationGenerationGeneration
Applicability Applicability Applicability Applicability
to UK to UK to UK to UK
NetworkNetworkNetworkNetwork
BenefitsBenefitsBenefitsBenefits Implementation Implementation Implementation Implementation
BarriersBarriersBarriersBarriers TimescalesTimescalesTimescalesTimescales
Mitsubishi Electric Ltd
SF6 Distribution Transformers
Medium 11kV to 33kV
Increased substation
capacities due to smaller
footprint.
None In use
Page 31
6.26.26.26.2 Overhead Lines and Cables Overhead Lines and Cables Overhead Lines and Cables Overhead Lines and Cables
ManufacturerManufacturerManufacturerManufacturer Product/ Product/ Product/ Product/
TechnologyTechnologyTechnologyTechnology
Potential to Potential to Potential to Potential to
AAAAllow llow llow llow
Increased Increased Increased Increased
GenerationGenerationGenerationGeneration
Applicability Applicability Applicability Applicability
to UK to UK to UK to UK
NetworkNetworkNetworkNetwork
BenefitsBenefitsBenefitsBenefits Implementation Implementation Implementation Implementation
BarriersBarriersBarriersBarriers TimescalesTimescalesTimescalesTimescales
Nexans Superconducting Power Cables
Medium
Initially 132kV
and above
due to costs
Increased circuit capacities,
reduction of voltage
regulation problems.
Lower losses.
Installation costs would
be higher than for
existing cables. Cost and
lead time to large scale
production.
May increase fault levels.
Not known
KEMA Dynamic Cable Rating Equipment
Low All
Provides actual cable rating
based on installation
conditions.
Could be employed on
future cables if
manufacturers incorporate
optical fibre temperature
measurement into cables
May not provide
significant increase in
capacity, requires
retrofitting to existing
cables or installation of
new cables.
Available now
Composite Technology Corporation
Composite Overhead Conductors
Medium
Initially 132kV
and above
due to cost
Higher ratings possible
without constructing new
circuits. Installation
methods identical to
existing conductors.
Cost – intended to
provide cost saving over
GAP type conductors
Available now
Page 32
6.36.36.36.3 SVCs, FACTS and STATCOMsSVCs, FACTS and STATCOMsSVCs, FACTS and STATCOMsSVCs, FACTS and STATCOMs
ManufacturerManufacturerManufacturerManufacturer Product/ Product/ Product/ Product/
TechnologyTechnologyTechnologyTechnology
Potential to Potential to Potential to Potential to
Allow Allow Allow Allow
Increased Increased Increased Increased
GenerationGenerationGenerationGeneration
Applicability Applicability Applicability Applicability
to UK to UK to UK to UK
NetworkNetworkNetworkNetwork
BenefitsBenefitsBenefitsBenefits Implementation Implementation Implementation Implementation
BarriersBarriersBarriersBarriers TimescalesTimescalesTimescalesTimescales
ABB FACTS, HVDC Light, SVC
Medium 132kV and
above.
Improves steady state and
dynamic performance of
the network
Substation space.
Cost.
Available now
AREVA C-STATCOM Medium 11kV to 132kV
Improves steady state and
dynamic performance of
the network.
Can include energy storage
to give four quadrant
operation.
±10MVAr modules up to
±50MVAr
Substation space.
Cost.
Q4 2005
American Superconductors
D-VAR (STATCOM) devices
Medium 480V to 35kV
Improved power quality,
steady state and dynamic
voltage control.
1.0 to 8.0MVAr capability
Substation space.
Cost.
Available now
Page 33
ManufacturerManufacturerManufacturerManufacturer Product/ Product/ Product/ Product/
TechnologyTechnologyTechnologyTechnology
Potential to Potential to Potential to Potential to
Allow Allow Allow Allow
Increased Increased Increased Increased
GenerationGenerationGenerationGeneration
Applicability Applicability Applicability Applicability
to UK to UK to UK to UK
NetworkNetworkNetworkNetwork
BenefitsBenefitsBenefitsBenefits Implementation Implementation Implementation Implementation
BarriersBarriersBarriersBarriers TimescalesTimescalesTimescalesTimescales
SuperVAR HTS synchronous compensator
Medium 13.8kV
Improved power quality,
steady state and dynamic
voltage control.
±10.0MVAr with up to
8.0pu transient rating.
Substation space.
Cost.
Available now
American Superconductors
D-SMES HTS Magnetic Energy Storage System
Low to
medium 69kV to 500kV
Dynamic delivery of real
and reactive power during
fault conditions allowing
possibility of generator
fault ride though and
islanding.
3MW and 8MVAr
capability.
Substation space.
Cost.
Available now
Page 34
6.46.46.46.4 Switchgear and Fault Current LimitersSwitchgear and Fault Current LimitersSwitchgear and Fault Current LimitersSwitchgear and Fault Current Limiters
ManufacturerManufacturerManufacturerManufacturer Product/ Product/ Product/ Product/
TechnologyTechnologyTechnologyTechnology
Potential to Potential to Potential to Potential to
Allow Allow Allow Allow
Increased Increased Increased Increased
GenerationGenerationGenerationGeneration
Applicability Applicability Applicability Applicability
to UK to UK to UK to UK
NetworkNetworkNetworkNetwork
BenefitsBenefitsBenefitsBenefits Implementation Implementation Implementation Implementation
BarriersBarriersBarriersBarriers TimescalesTimescalesTimescalesTimescales
Switchgear Improvements based on new materials technologies
Not known Not known
More compact switchgear
allowing more circuits per
substation
Development of new
materials Not known
Medium Voltage Intelligent VCB
Low 11kV
Measurement, control and
protection functions all
incorporated into circuit
breaker. Internet type
interface allows remote
control of all functions
None Available now
ABB
Solid State Circuit Breaker
Low Not known Faster operation, reduced
maintenance. Design issues to resolve Not known
AREVA Superconducting Fault Current Limiter
High 3.5kV to 35kV
Allows increased fault
levels and therefore
increased distributed
generation.
Failsafe operation
Not known Not known
Page 35
ManufacturerManufacturerManufacturerManufacturer Product/ Product/ Product/ Product/
TechnologyTechnologyTechnologyTechnology
Potential to Potential to Potential to Potential to
Allow Allow Allow Allow
Increased Increased Increased Increased
GenerationGenerationGenerationGeneration
Applicability Applicability Applicability Applicability
to UK to UK to UK to UK
NetworkNetworkNetworkNetwork
BenefitsBenefitsBenefitsBenefits Implementation Implementation Implementation Implementation
BarriersBarriersBarriersBarriers TimescalesTimescalesTimescalesTimescales
AREVA Magnetic Fault Current Limiter
High 3.5kV to 35kV
Allows increased fault
levels and therefore
increased distributed
generation.
Fail safe operation.
Not known Not known
Nexans Superconducting Fault Current Limiter
High Not known
Fail safe control of fault
levels. May reduce
reinforcement costs.
Cost. Substation space.
Cooling equipment.
Possibly 5
years to
commercial
availability
Page 36
7.7.7.7. SECONDARY PLANT RESUSECONDARY PLANT RESUSECONDARY PLANT RESUSECONDARY PLANT RESULTS SUMMARYLTS SUMMARYLTS SUMMARYLTS SUMMARY
This sections details the manufacturers and their technologies with likely benefits from section 5 in tabular format. It should be
noted that the results column ‘Potential to Allow Increased Generation’ are subjective. Factors considered when determining the
potential are the ability to control increasing quantities of distributed generation. Technologies which relieve system bottlenecks
have been classified as having a lower potential to allow additional generation to be connected.
7.17.17.17.1 SCADA Systems and Substation AutomationSCADA Systems and Substation AutomationSCADA Systems and Substation AutomationSCADA Systems and Substation Automation
ManufacturerManufacturerManufacturerManufacturer Product/ Product/ Product/ Product/
TechnologyTechnologyTechnologyTechnology
Potential to Potential to Potential to Potential to
Allow Allow Allow Allow
Increased Increased Increased Increased
GenerationGenerationGenerationGeneration
Applicability Applicability Applicability Applicability
to UK to UK to UK to UK
NetworkNetworkNetworkNetwork
BenefitsBenefitsBenefitsBenefits Implementation Implementation Implementation Implementation
BarriersBarriersBarriersBarriers TimescTimescTimescTimescalesalesalesales
ABB SCADA, EMS Systems
High All voltages Fully integrated solutions
with advanced functionality.
DNOs may only be using the basic product
features.
Available now
AREVA e-terra SCADA/EMS
High All voltages
Fully integrated system allowing control over all system devices from
individual generators to system wide power
control.
None Available now
Remsdaq CallistoIES High Already in
use
Integrated control and monitoring of multiple
plant items. Wide range of communications protocols
and media
None Available now
Page 37
ManufacturerManufacturerManufacturerManufacturer Product/ Product/ Product/ Product/
TechnologyTechnologyTechnologyTechnology
Potential to Potential to Potential to Potential to
Allow Allow Allow Allow
Increased Increased Increased Increased
GenerationGenerationGenerationGeneration
Applicability Applicability Applicability Applicability
to UK to UK to UK to UK
NetworkNetworkNetworkNetwork
BenefitsBenefitsBenefitsBenefits Implementation Implementation Implementation Implementation
BarriersBarriersBarriersBarriers TimescTimescTimescTimescalesalesalesales
Econnect GenAVC Medium 11kV
Can allow up to a doubling of size of DG schemes. Provides adjustment of voltage set points to optimise the network
voltages.
Acceptance of new concept by DNOs.
Development of 5-6MW schemes for 11kV
connection.
Ready for installation end
2005
Econnect Load Controller Low to medium
All voltages. Suited to
islanded and interconnecte
d grids (especially
weak systems)
Automatic load shedding system to mitigate voltage rise issues and maximise use of on-site generated
electricity
Under development September
2005
Page 38
8.8.8.8. CONCLUSIONSCONCLUSIONSCONCLUSIONSCONCLUSIONS
8.18.18.18.1 TransformersTransformersTransformersTransformers
Superconducting transformers are currently under development with no firm dates or
costs given for production units. It is considered that some units may be available
before 2010. There would be issues arising from the cooling system such as the
increased complexity and requirement for liquid nitrogen supplies. There would be
environmental benefits as insulating oils would not be required. They may allow
additional generation to be connected due to their improved voltage regulation
characteristics, but these would also result in higher fault levels.
Solid state tap changers are being developed which may provide more flexible system
operation. These may allow more generation to be connected if retrofitted to existing
transformers with limited reverse power capability. Costs were not available but it is
expected that production units would be available before 2010.
Two position tap changers may also provide greater system flexibility, especially if
they can replace existing fixed or off load tap changers. These would allow more
generation to be connected due to the larger voltage range. Costs were not available
but it is expected that production units would be available before 2010.
Dynamic rating equipment would allow the full temperature range, and therefore
power range, of transformers to be utilised. This equipment is in use outside the UK
and can be retrofitted. It may allow increased levels of distributed generation, but
only where network thermal capacity starts to constrain the allowable levels of
generation.
In-line voltage regulators have been shown to provide positive benefits and allowed
the connection of additional generation. They are not in widespread use in the Great
Britain but they have been included in this report due to the benefits provided.
8.28.28.28.2 Overhead Lines and CablesOverhead Lines and CablesOverhead Lines and CablesOverhead Lines and Cables
Superconducting power cables have been developed and are undergoing trials. No
costs or production dates were available. They would allow higher powers to be
transferred along the same cable corridor which may have benefits in congested
urban areas. The reduced impedance may allow more generation to be connected but
the advantages over conventional cables are considered to be marginal.
Dynamic conductor monitoring systems are in use outside the UK. They allow an
accurate cable rating to be determined which may increase the power transfer
capability of circuits. These systems may allow marginally more generation to be
connected where there are high levels of connected generation.
Page 39
Composite overhead conductors would allow existing overhead circuits to be
substantially up-rated. In areas where there is a high concentration of generation their
use may allow more generation to be connected.
8.38.38.38.3 SVCs, FSVCs, FSVCs, FSVCs, FACTS and STATCOMsACTS and STATCOMsACTS and STATCOMsACTS and STATCOMs
A variety of SVC and STATCOM type devices are available and use around the world
and in the UK at transmission voltage levels. Due to the cost these devices are
normally employed at transmission level. Smaller more cost effective devices are
becoming available which would allow improved steady state and dynamic system
performance at distribution voltage levels. They could allow the connection of
additional generation by improving the fault ride through capability and providing
additional voltage regulation. The relatively high costs of these devices are
considered to be a barrier, in the short term at least, to their widespread use in the UK.
Distribution voltage SVCs are being installed by one DNO where in-line voltage
regulators do not provide a sufficient degree of voltage control.
8.48.48.48.4 Switchgear and Fault Current LimitersSwitchgear and Fault Current LimitersSwitchgear and Fault Current LimitersSwitchgear and Fault Current Limiters
A number of superconducting FCLs are under development. It is expected that these
would be available before 2010. They could allow significant amounts of additional
generation to be connected to systems where there would otherwise be fault level
issues.
Intelligent circuit breakers are available which have all the necessary functionality built
in including Internet type interfaces to allow remote operation. These would not
directly allow more generation to be connected but may make new connections more
cost effective.
New material technologies are expected to provide more compact switchgear
components that may result in the ability to install more equipment in existing
substations. This in turn may allow the connection of more generation.
8.58.58.58.5 SCADA Systems and Substation AutomationSCADA Systems and Substation AutomationSCADA Systems and Substation AutomationSCADA Systems and Substation Automation
Several organisations and institutions21, 22, 23, 24 in the US are undertaking R&D on
micro-grid network controllers. These would provide real time control for all active
devices on a section of distribution network. They would provide an interface
between the complexity of the distribution network and the centralised DNO control
system. Such systems should provide a simplified system for connecting a variety of
low voltage generators (DCHP, solar, micro wind etc) into a local distribution system.
Centralised SCADA/EMS systems are being continually developed to provide more
functionality. Advanced features include wind speed prediction, control of individual
generators and wind farms and market modelling. The increased capabilities will
allow additional generation to be more easily integrated into the existing system.
Page 40
Improved methods of controlling the tap changers of 33kV/ 11kV (primary)
transformers are already developed and undergoing field trials on two distribution
networks. Power measurements are used to control the primary transformer tap
changer to enable the maximum generation to be connected whilst ensuring that all
voltages are maintained within acceptable limits. Studies undertaken to date indicate
that GenAVC™ could double the amount of generation that could be connected to a
network. It is expected to be in production in approximately 12 months.
Intelligent generation controllers are being developed that should allow improved
voltage control for systems incorporating generators. By optimising generator
operation the system should maximise the amount of generation that can be
connected to the system.
8.68.68.68.6 Communications SystemsCommunications SystemsCommunications SystemsCommunications Systems
No major communications related R&D activities were identified as part of this report.
New developments are utilising existing communications technologies to provide the
functionality required.
The main barrier to allowing increased amounts of generation is considered to be the
development of the communications infrastructure to support the needs of the various
technologies. Existing SCADA communications networks are considered to be
unreliable and too slow for the control of significant quantities of distributed
generation. As increased quantities of generation are installed a reliable, high speed
communications network may need to be established in order to provide the DNO
with sufficient levels of control and monitoring.
The suitability of existing communications protocols may need to be examined to
ensure compatibility between the DNOs and consumers’ equipment. IEC61850
specifies a communication standard for substation devices but not for devices located
elsewhere on the distribution system.
8.78.78.78.7 OthersOthersOthersOthers
A first generation expert system has been developed to evaluate connections options
for 11kV networks. Further software development and testing is underway to expand
the range of applicable voltages to 132kV. The system examines the impact of
proposed generation on voltage profiles and fault levels then identifies the most cost
effective connection.
More advanced design and analysis tools will be required in order that developers and
DNOs can design and operate networks comprising active management systems and
high levels of distributed generation more effectively.
Page 41
8.88.88.88.8 SummarySummarySummarySummary
Most manufacturers’ R&D programmes are market led. Therefore products will only
be developed if a market has been identified. Some manufacturers have reported
issues with identifying customers’ needs and the uncertainty of future energy system
policy changes.
From the reviews undertaken it has been concluded that the most influential
technologies, in terms of maximising the potential for new generation, that should be
available before 2010 are: -
• Super-conducting Fault Current Limiters
o These devices would potentially remove any fault level issues where
additional generation may result in existing switchgear being
overstressed.
• SVCs, FACTS and STATCOMs
o These devices have been used to resolve voltage regulation issues
where generation is present. They can also improve power quality
but their high cost may restrict their application.
• In-line Voltage Regulators (not yet in wide-spread use)
o Although in-line voltage regulators are in use in the UK and therefore
outside the scope of this report, it is considered that they can allow
significant quantities of additional generation to be installed. This,
together with their very limited use in the UK, has resulted in their
inclusion.
• Micro-grid Controllers
o First generation controllers will soon be available which allow
generators to be incorporated into distribution systems whilst
maintaining satisfactory voltage control.
A number of areas were identified where further work may be required in order to
remove any potential barriers to the connection of additional generation. These are: -
• Communications Networks
o The successful connection and operation of large quantities of
distributed generation will require a high speed reliable
communications network to be established.
• Communications Protocols
Page 42
o No standards were identified which covers communications
protocols between the substation and remote devices on the
distribution system.
The only overseas practice identified by manufacturers as being an improvement on
current UK practice was making fuller use of SCADA/EMS product features to improve
system operation and flexibility. Whilst this may allow additional generation to be
installed and easily controlled, the combination of the existing SCADA and
communications systems employed are not generally considered suitable for
controlling large numbers of distributed generators.
Page 43
9.9.9.9. REFERENCESREFERENCESREFERENCESREFERENCES
1 EPSRC SuperGen Initiative, Workshop on Future Technologies for a Sustainable Electricity System,
November 2003, http://www.econ.cam.ac.uk/dae/Supergen-workshop/programme.html 2 University of Canterbury website. http://www.comsdev.canterbury.ac.nz/news/2004/040310a.shtml
3 Waukesha Electric Systems. http://www.waukeshaelectric.com/
4 Mitsubishi Electric Ltd, http://www.mitsubishielectric.com.hk/mehk/p&m/MAR/transform/sf6gis.htm
5 Dynamic Ratings Selected by Kansas Utility, T&D World, July 2004
http://tdworld.com/mag/power_dynamic_ratings_selected
6 Cooper Industries, http://www.cooperpower.com/Products/Voltage
7 Energy Networks Association, Engineering Technical Report 126, Guidelines for Actively Managing
Voltage Levels Associated with the Connection of a Single Distributed Generation Plant, August 2004.
8 J. W. Ekin, Superconductors – An Emerging Power Technology, 2004,
http://www.boulder.nist.gov/div818/81803/publications/ekin/GDX(2004).pdf
9 KEMA Dynamic Current Rating Optimisation, http://www.kema.com/
10
Extracting More Value with Intelligent Cable Systems, Transmission & Distribution World, Aug 1
2004 11
S. Sadler, 1600MVA Electrical Power Transmission with an EHV XLPE Cable System in the
Underground of London, CIGRE 2004 12
H. Ishihara, Development of Pre-Stretch Type Up-Rating Conductor to Realise Cost Reductions,
CIGRE 2004. 13
Composite Technology Corporation, www.compositetechcorp.com
14
American Superconductors, http://www.amsuper.com/
15
Nexans, http://www.nexans.com/internet/Welcome.nx
16
Demonstration of a Superconducting Fault Current Limiter, EPRI, Project P122.003,
http://www.epri.com/D2004/
17
ABB, www.abb.com
18
Econnect, www.econnect.co.uk
19
Remsdaq, www.remsdaq.com
Page 44
20 ScottishPower plc, Network Management Systems for Active Distribution Networks – a Feasibil ity
Study, K/EL/00310/REP, 2004. 21
NREL, Reliable, Low Cost Distributed System Generator/Utility System Interconnect,
www.nrel.gov/publications/
22
NREL, Innovative Distributed Power Interconnection and Control Systems,
www.nrel.gov/publications/
23
NREL, Intelligent Solutions for Distributed Power Technology, www.nrel.gov/publications/
24
Consortium for Electric Reliabil ity Technology Solutions, http://certs.lbl.gov/certs.html 25
IEC61850, Communication Networks and Systems in Substations, 2003
Page 45
APPENDIX A
Study Brief
Page 46
New Technologies – To Facilitate Increased Levels of Distributed Generation
Study Brief
Purposes of Study
1. To identify what new technologies are available or emerging (in UK and world-wide) to
facilitate increased levels of Distributed Generation (DG) in the time frame to 2010
2. To provide a summary of the status of emerging technologies to help inform decisions about
what further work might be appropriate in this area.
Approach to Study
The study will be carried out in three stages.
Kick-off Meeting
A draft study brief will be prepared prior to the kick-off meeting. This document will define the scope of
the work required to undertake a structured and well-managed study. The Brief will describe the
approach to the Study; Risks/Dependencies/Assumptions; Quality Assurance etc.
At the kick-off meeting with the WS Project Manager, the study brief will be reviewed and approved,
and the number of manufacturers to be interviewed will be agreed.
Information Gathering
This stage will comprise the bulk of the work. It will include the following activities: -
• Identification of possible manufacturers/contacts and preparation of the questionnaire for the
interview with manufacturers
• Review of international developments from the literature: DTI/DGCG commissioned reports,
IEE, IEEE, CIGRE, Tyndall Centre, EPRI, web sources etc. Note will be taken in particular of
earlier DGCG studies, ‘Survey Study of Status and Penetration Levels of Distributed
Generation (DG) in Europe and the US (stage one and two)’ by KEMA (K/EL/00306/02/REP)
and ‘Network Integration of Distributed Generation: International Research and Development’
by SPRU (K/EL/00307/REP)
• Discussions with specialists within PB Power
• Telephone discussions with academic contacts
• Administration of questionnaires and/or structured interviews with selected manufacturers
This will be a world-wide review. It is envisaged that the technologies to be covered would include
primary and secondary plant infrastructure, telecommunications and IT. These technologies may
not yet be fully developed, commercially available, or be cost effective, compared to more
traditional approaches, but they should have the potential to be so by 2010. Existing technologies
not currently employed in the UK will also be covered. Only network related technologies will be
covered, ie generation related technologies will be omitted. Specific technologies to be addressed
Page 47
could include wind generator control systems, SVC’s, FACTS and STACOM developments,
superconducting fault current limiters, in-line voltage regulators, substation automation and
integration of generator/voltage control, SCADA systems and associated communications.
Manufacturers to be contacted could include the following: -
1. ABB at Stone, Staffordshire for on-going developments in SVC (to stabilise voltage
fluctuations and provide grid interconnection); FACTS devices for wind generator
connections; Superconducting Fault Current Limiters etc
2. Siemens Power T&D Group at Manchester for developments in substation automation
systems
3. Peter Brotherhood based at Peterborough for innovations in designing and manufacturing
equipment for use in renewable energy applications
4. GE Wind Energy Systems for developments in wind turbines
5. VA Tech T&D for new switchgear developments
6. Eurowind Developments Limited for innovations in wind turbines
7. Alstom at Stafford
8. Thales Information Systems
The manufacturers to be contacted will be determined from the document reviews and discussion
with PB Power specialists in the UK and overseas.
Rev iew and Reporting
The final stage will consist of the following: -
• Review of information gathered and preparation of DRAFT report
• Review of comments from Work Stream
• Preparation of Final Report
The report will include: -
1) Tabulations of manufacturers and their products/technologies.
2) Classification of these technologies into functional groups.
3) Review and discussion of each of these groups of technologies covering:
• their function and applicability to the UK system.
• their potential to integrate more generation
• the ease with which they could be incorporated into existing systems and any issues which would
have to be addressed,
• their l ikely cost/benefit
• the timescales on which they are likely to become available
• a comparison of (advantages and disadvantages of) the different products / technologies
competing within each group
4) Conclusions about the impacts these technologies could have within the timescale of interest.
Page 48
Information that is commercially sensitive to a manufacturer will be presented in an appendix or
similar and would not be placed in the public domain.
Reports would be produced in either Microsoft Word or Adobe Acrobat format as required by the
workstream.
Assumptions
It is assumed that this work will build on previous reports delivered under the DTI New & Renewable
Energy Programme, and will not go back over the same ground. Material presented in earlier reports
will not have to be reiterated in detail.
Risks
A lot of the input for this report will come from the manufacturers. There will therefore be risks
associated with the quality and timeliness of the information provided. There may also be difficulties in
commercial confidentiality. This will be addressed by contacting the manufacturers ahead of sending
the questionnaire and carrying out a structured interview, in order to identify the correct individual to
approach, and to ensure that the purpose of the exercise is fully understood. The benefits to the
manufacturer in contributing to the report will be highlighted, and any confidentiality concerns
discussed and addressed. Any material which the manufacturers consider confidential will not be
published in the public domain report but may be included in a restricted appendix.
Staffing and QA
The majority of the work will be carried out by a senior engineer, Steve Ingram, who has
experience of carrying out previous studies for the DTI N&RE Programme, and meeting the
requirements of a DGCG workstream.
Guidance and peer review will be provided by Katherine Jackson and John Douglas. Katherine has
managed other DTI N&RE projects, and John has extensive experience of distribution network
technologies.
Timescales
It is intended to produce a Draft Final report by the 24th
September 2004 to allow it to be presented at
the workstream meeting on the 30th September. The Final version of the report will be issued in mid
October, assuming that workstream comments are received within approximately two weeks. This will
depend to some extent on the speed of response of the manufacturers
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APPENDIX B
Questionnaires sent to Manufacturers
Page 50
APPENDIX B –Questionnaires sent to Manufacturers
The following questionnaire was sent out to a number of manufacturers with UK offices.
Manufacturers Questionnaire
We have been asked by the Department of Trade and Industry (DTI) in the UK to establish the status
of the new technologies that could influence the power distribution industry over the next ten years.
The purpose of this study is to identify the potential new technologies that may be applied in the UK
and to enable them to concentrate their R&D funding on technologies that may have a commercial
future.
Specifically the DTI’s requirements are summarised as follows: -
“This will be a world-wide review. It is envisaged that the technologies to be covered would
include primary and secondary plant infrastructure, telecommunications and IT. These
technologies may not yet be fully developed, commercially available, or be cost effective,
compared to more traditional approaches, but they should have the potential to be so by
2010. Existing technologies not currently employed in the UK will also be covered. Only
network related technologies will be covered, ie generation related technologies will be
omitted. Specific technologies to be addressed could include wind generator control systems,
SVCs, FACTS and STATCOM developments, superconducting fault current limiters, in-line
voltage regulators, substation automation and integration of generator/voltage control,
SCADA systems and associated communications.”
We understand from publicity that your company may be involved in product development or R&D
which could enhance the current UK distribution system and allow the connection of increasing levels
of distributed generation.
As detailed in the covering e-mail we would like to meet to discuss your company’s plans for such
technologies. In order that we can have a useful discussion we have compiled some questions,
below, which we would use as a basis for any meeting: -
• Outline any current products which are used in overseas distribution systems which could
benefit the UK system
• Are any products in development that may increase the ability of distribution systems to
accept more distributed generation, or to delay reinforcement?
• If possible, discuss the company’s current areas of research on distribution technologies
• Outline the areas in which the company expects current distribution technologies to develop
over the next five years
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• Outline the areas in which the company intends to undertake research over the next five
years
The DTI is actively encouraging increased levels of distributed generation, and therefore the current
distribution system may require significant changes in order to satisfy future needs. Funding may be
available to support any technologies or R&D projects that aim to improve the capacity of the current
distribution system.
We acknowledge that there will almost certainly be confidentiality issues surrounding your research
and products. In order that the DTI gains the most benefit from this study we would be willing to abide
by a confidentiality agreement in order that sensitive information would not be disclosed. Such
information would be included in a report appendix but would not form part of the document released
into the public domain.
The following questionnaire was sent out to a number of manufacturers with no UK offices.
Sirs,
We have been asked by the Department of Trade and Industry (DTI) in the UK to establish the state
of the new technologies that could influence the power distribution industry over the next ten years. The purpose of this study is to identify the potential new technologies that may be applied in the UK
and to enable them to concentrate their R&D funding on technologies that may have a commercial future.
Specifically the DTI’s requirements are summarised as follows: -
“This will be a world-wide review. It is envisaged that the technologies to be covered would include
primary and secondary plant infrastructure, telecommunications and IT. These technologies may not yet be fully developed, commercially available, or be cost effective, compared to more traditional
approaches, but they should have the potential to be so by 2010. Existing technologies not currently employed in the UK will also be covered. Only network related technologies will be covered, ie
generation related technologies will be omitted. Specific technologies to be addressed could include wind generator control systems, SVCs, FACTS and STATCOM developments, superconducting fault
current limiters, in-l ine voltage regulators, substation automation and integration of generator/voltage control, SCADA systems and associated communications.”
We understand from your publicity that you are presently working on dynamic reactive compensation, high temperature superconductor cables and other methods of improving power quality.
Would you be able to confirm that you are still working on these technologies and when they are
expected to reach the commercial market?
We would also appreciate any information about any other exciting areas of research that you are undertaking that could be of interest to the power generation or power distribution industries.
We acknowledge that there may be confidentiality issues surrounding your research and products, but
would of course welcome any high level information that you would be prepared to share.
Many thanks for your time and cooperation
Best Regards
Page 52
Stephen Ingram
Senior Power Systems Engineer
PB Power Ltd
Energy and Uti li ty Consulting
Manchester Technology Centre
Oxford House
Oxford Road
Manchester
M1 7ED
<mailto:[email protected]>
Direct Line: 44(0)161 200 5203
Fax: 44(0)161 200 5001
Page 53
APPENDIX C
Responses from Manufacturers
Page 54
APPENDIX C – Manufacturers Responses
The following pages contain the results of the manufacturers written responses to the various
questionnaires.
Page 55
Company /
Institution: - University of Canterbury / CanterburyTX
Technology: - Transformers
Products: - High Temperature Superconducting Transformers
The University of Canterbury (NZ) is currently undertaking research into the development of
HTS transformers. CanterburyTX is the company responsible for manufacturing the
prototype and possibly production transformers.
In addit ion to the details obtained from the w ebsite additional correspondence w as
conducted as follows: -
From: Bodger, Pat [[email protected]]
Sent: 30 September 2004 22:44
To: Ingram, Stephen
Subject: RE: DTI New Technologies
Hi Steve
What are the reactance characteristics of an HTS transformer compared to
normal power transformers?
>With respect to leakage reactance it is smaller because of the thinness
and
the flux exclusion effects of HTS wire. You don't get the same leakage
flux.
>With respect to the magnetizing reactance, our partial core transformer
has
a higher reluctance for the magnetic circuit than a conventional full core
transformer. This means a lower magnetizing inductance and hence
reactance.
Hence there is an increase in shunt reactive current going into the
transformer. This is not necessarily a bad thing as it could be useful for
reactive compensation of cable capacitance.
If the reactance is significantly reduced then there may be no need for a
tap changer? Voltage regulation on the LV side may be improved and fault
levels increased.
> In this you are referring to the leakage reactance. I can agree with
your
statements. Voltage regulation on our unit is low relative to a normal
transformer.
Also, would you be able to provide some information with regards to any
future power system related R&D projects which you may be involved in?
> While the HTS transformer is our main thrust, we have developed a
resonant testing transformer and are looking at our HTS transformer as a
reactive compensator and fault current limiter.
Hope these responses are useful, but you may also wish to visit the
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department website www.elec.canterbury.ac.nz and look under Research groups
and the Electric Power Engineering Centre and the Power Engineering Group.
These will give you an overview of the extent of our research.
Best regards
Pat
Page 57
Company /
Institution: - Remsdaq
Technology: - Remote Terminal units (RTUs)
Products: - CallistoIES
Meeting Date: - 7th October 2004
Location: - PB Pow er Offices, Manchester
Remsdaq are a UK based company developing and marketing RTUs to the pow er
generation and distribution business. In addit ion to the interview they provided a w ritten
response to the questionnaire as reproduced below : -
I - Response to Questionnaire
Q1- Outline any current products which are used in overseas distribution systems which could benefit
the UK system.
A1- Remsdaq’s Callisto RTU has been used widely both in Overseas and UK electricity distribution
systems. Please see the attached application summary entitled ‘Callisto in Power Distribution’.
Q2- Are any products in development that may increase the abil ity of distribution systems to accept
more distributed generation, or to delay reinforcement?
A2- Callisto RTU already provides functionality and features applicable to distribution automation and
distributed generation. Please refer to the attached application summary entitled ‘Callisto in Power
Distribution’.
Q3- If possible, discuss the company’s current areas of research on distribution technologies.
A3- Remsdaq places great emphasis on its research and development facil ities, and has a strong
R&D Department. The Company’s development plans are both technology and customer based to
meet the needs of the ever increasing worldwide de-regulated electricity industry.
Current development areas include the next generation Callisto RTU taking advantage of latest
electronics / microprocessor technologies and available components, with an expandable and
innovative hardware platform. Ethernet connectivity and GPRS communications are the latest
additions to the Callisto networking and communication facilities.
Q4- Outline the areas in which the company expects current distribution technologies to develop over
the next 5 years.
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A4- Relevant to the RTU element, IEC61850 standard is an important area of development. An area
which also should be looked at is the definition of a 3-phase object within the protocol(s).
Developments / advances in communications technology / systems / equipment will open other areas
for RTU development. These would be expected to include utilising low cost communications media,
communication speeds, and communications security.
Current areas of interest to the distribution network operators include fault condition monitoring and
asset management and control, some of which are already within the RTU capabilities, with further
developments / facil ities are in sight.
Q5- Outline the areas in which the company expects current distribution technologies to develop over
the next 5 years.
A5- Please see A4 above.
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II_- Callisto in Power Distribution
1- Selected Callisto features
a)- Callisto is an advanced technology, versatile, and flexible RTU. It can provide most, if not all,
information for the monitoring, control and protection of the electricity network. Utilising a networked
distributed architecture, the RTU can be used in both distributed and concentrated arrangements.
The unit is fully scalable and is suitable for use in RTU applications ranging from small (e.g. pole-
mount) to large (e.g. fully equipped primary transmission and distribution substations). The product is
specifically designed to meet the needs and requirements of the electric utili ty sector, and has been
type tested to stringent EMC and Environmental standards.
b)- Callisto has a fully flexible RTU functionality, which is augmented by its inherent intelligence. The
unit is fully user configurable, and user programmable for automation and logic functions using
IEC61131-3 guidelines. Programmes can be designed with over 1000 logic and arithmetic functions
including PID controllers. RTU Programmes can reside on specific nodes or can be distributed
across the entire remote. Example applications for embedded generation would include load
shedding, generator / load scheduling, and alike (please see 2 below).
c)- Callisto’s transducerless technology allows direct connection of AC signals from VTs and CTs.
Signals are sampled at 128 samples per cycle, with simultaneous (synchronous) sampling of
individual voltage and current phases to allow true rms calculation of voltages and currents to high
levels of accuracy. Using a dedicated DSP (Digital Signal Processor) metering values including real
power, reactive power, total power, kWh, kVARh (import, export, net), are calculated per phase
and in total. Other calculated power parameters include power factor (per phase), supply
frequency, and neutral current.
In addition, power quality and supply analysis data are computed for positive, negative and zero
phase sequence components, and for indiv idual v oltage and current harmonics up to the 50th
and THD (Total Harmonic Distortion) using advanced FFT (Fast Fourier Transform) algorithms for
harmonics calculations.
Analogue Limit Excursions (ALEs) against user defined limits are time stamped and recorded (for
surges, sags, and other transients).
Disturbance recording facil ities within each RTU node allows the recording of disturbances for 12 user
assignable data tracks, each providing 1 second of data, with 3 sets of buffer registers allowing the
storage of multiple disturbances. Such information can be used by the user for disturbance analysis,
network design / optimisation, etc.
d)- Callisto supports a variety of communication media, including fixed circuits, fibre optics, dial up
(PSTN), UHF radio, low power radio, private mobile radio (PMR), power-line carrier (PLC),
Paknet, GSM, Satellite, Ethernet, GPRS, etc.
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The RTU has a rich library of communication protocols ranging from industry standard protocols such
as DNP3.0, DNP3.0 I/P, IEC60870-5-101, IEC60870-5-103, IEC60870-5-104, Modbus, to proprietary
protocols (e.g. ABB SPA-Bus, Areva K-series & M-series, Siemens, SEL, GE DFP & DLP, etc.), for
communication with SCADA/EMS/DMS master stations and IED.
A variety of communication topologies and architectures including master-slave, master-master,
multiple master, slave RTUs and IEDs, point-to point, point-to-multipoint, multi-dropped,
backup and redundant bearers, etc. are available with Callisto. RTU redundancy is also available
for mission critical systems.
2- Applications in Distributed / Embedded Generation
a)- At the generator plant the RTU can be utilised for the monitoring and control of local plant. The
RTU can be scaled to suit the plant I/O requirements and where existing RTUs and PLCs are used it
can also be used to interface with such units through a variety of protocols.
The transducerless features can be used to derive direct power measurements and calculate / record
parameters and data such as real and reactive power, total power, kWh, kVARh, (import, export, net)
per phase and total, power factor per phase, supply frequency, power quality and harmonics,
transients and disturbance data. The RTU’s synchronising facilities can be used for synchronisation
of the plant output with the network. The ability of the RTU to readily establish / calculate import and
export of power provides valuable information for load scheduling / forecasting applications.
Automatic control of the plant can be used by utilising the flexible user defined logic applications. The
generator plant RTU can also communicate with (and be remotely controlled from) SCADA/EMS/DMS
master station or ‘master’ RTU(s) (e.g. RTU at primary substation or control centre, etc.). Such
automation would allow automatic connection / disconnection of the generator from the network in
case of defined faults / conditions, at scheduled intervals, due to outage of other duty generators,
network faults, network operational strategies, schedules, supply routings / re-routings, etc.
b)- RTUs at secondary substations, ground mounts, pole-mounts can be employed for the monitoring
and control of plant data and network conditions. Local automation functions can be defined using the
RTU’s flexible user defined logic functions / applications. This could also include automatic
transformer tap changes.
The transducerless configuration can be used to derive direct power measurements and calculate /
record parameters and data such as real and reactive power, total power, kWh, kVARh, (import,
export, net) per phase and total, power factor per phase, supply frequency, power quality and
harmonics, transients and disturbance data.
The RTU can also communicate with (and be remotely controlled from) SCADA/EMS/DMS master
station or ‘master’ RTU(s) (e.g. RTU at primary substation or control centre, etc.) for network
operational strategies, supply routings / re-routings, and alike.
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c)- At the primary substation the RTU can be scaled to suit the local I/O requirements and the
communications with its slave RTUs and IEDs. The unit can be arranged in a distributed and / or
concentrated configuration to correspond with the plant requirements.
RTU’s intelligence and user defined logic capabilities can be utilised to define flexible control and
automation strategies for both local and remote control functions. Local automation could include
Line Throw Over (LTO), Bus Throw Over (BTO), under-frequency load shedding, transformer tap
control, etc. Remote automation functions could include network supply routings / re-routings,
generator scheduling, etc. Dependent on the arrangements and network topologies / operations, the
latter can encompass the monitoring and control / automation of large or small sections of the grid.
As a result of the readily available data (including power parameters calculated under the
transducerless arrangement at both the primary substations and its slave satellite RTUs) efficient
control algorithms can be defined to cover a variety of strategies including the control of reverse
power flow in primary transformers, import /export flow control, generator isolation under network fault
conditions, etc.
The RTU’s transducerless capabilities allows the derivation of direct power measurements and
calculation / recording of parameters and data such as real and reactive power, total power, kWh,
kVARh, (import, export, net) per phase and total, power factor per phase, supply frequency, power
quality and harmonics, transients and disturbance data.
The RTU can communicate both upwards to one or more SCADA/EMS/DMS masters and downwards
to ‘slave’ RTUs (e.g. secondary substation, pole-mount and ground-mount RTUs, etc.) using a library
if industry standard and proprietary protocols. A wide range of communications media are supported.