FYP Report up to date COMPLETE

Pumped Hydro Storage

By

Mr. Steven Sweeney

A project submitted in partial fulfilment requirements

For a

B.Sc. Renewable and Electrical Energy Systems

Limerick Institute of Technology

Submitted: 12/04/15

Supervisor: Mr. Ed Mullen

Pumped Hydro Storage Steven Sweeney K00181764

Renewable & Electrical Energy Systems 3rd Year FYP

Declaration I Steven Sweeney declare that this thesis on the research and build of a Pumped

Hydro Storage demonstration is my own work, and has not been submitted in any

other form for another award at any institution of education. Information taken from

the published or unpublished work of others has been acknowledged in the text and

a list of references is given.

Signed: ____________________ Signed: _________________

Steven Sweeney Ed Mullen

(Candidate) (Supervisor)

Date: ______________________ Date: ___________________

Dedication & Acknowledgements

I would like to dedicate this thesis to all the members of my family and my Fiancée

for all their support throughout the process of completing this final year project. I

would also like to thank my supervisor Mr. Ed Mullen and lecturers Mr. Pat Grace

and Mr. Keith Moloney for their much appreciated help and advice.



Abstract This project was completed to give the reader an in-depth understanding of the

operation of Pumped Hydro Storage and how valuable it can be as a storage hub for

different types of renewable energy resources. Ireland has not reached its full

potential in tapping into its own offshore wave and wind resources but has among the

best in Europe. The problem with renewable energy resources like wind and wave is

that they are highly variable and a lot of times are not in sync with demand. Therefore

instances such as curtailment come about and power is dumped because there is no

demand for it. This is where it is believed Pumped Hydro Storage can play a crucial

part in stopping power being dumped by simply using that surplus power to pump

water from a lower reservoir to an upper reservoir to be stored as potential energy for

use when required. This is a conversion of the over produced electrical energy into

potential energy which is then converted back to electrical energy but at a time when

needed.

In this thesis the research section chapter 2, goes into a lot of detail surrounding the

operation of a Pumped Hydro Storage plant; its different applications and a small

case study on Ireland’s only plant, “Turlough hill”. Chapter 3 gives an insight into how

a small build demonstration was planned out to perform as much of the same

features as a real Pumped Hydro Storage plant within certain size limitations. It also

showed the plans for the wiring requirements along with the PLC ladder code used to

control the process. Chapter 4 was the build phase, which shows how the

demonstration was put together from start to finish along with any challenges and

trade-offs that were faced. The demonstration was tested in chapter 5 and it was

discovered that the small DC generator was only producing 0.14W of power.

However, to find the relevant efficiencies the same principals were applied to testing

this project as would be applied in a real plant. The overall efficiency was very poor

because of a number of factors such as head height, the type of turbine and the

efficiency of the generator. This project did however meet its goal by successfully

lighting 3 LEDs totally independent of any other power source. Chapter 6 provided a

brief break down of some of the risks that could happen when demonstrating this

demo rig. The conclusion of this thesis offers some of the problems faced throughout

with some recommendations that would have further advanced this project.

.



Contents Declaration ................................................................................................................ 2

Dedication & Acknowledgements .............................................................................. 2

Abstract ..................................................................................................................... 3

1 Introduction ........................................................................................................ 8

2 Background Information (Research) ................................................................... 9

2.1 Hydro Power ............................................................................................... 9

2.2 Why choose Pumped Hydro Storage? ....................................................... 10

2.3 How Pumped Hydro Storage works ........................................................... 11

2.4 Irelands Potential for Pumped Hydro Storage ............................................ 12

2.5 Typical 24hr power demand in Ireland ....................................................... 13

2.6 Pumped Hydro Storage’s different applications ......................................... 14

2.7 Advantages of Pumped Hydro Storage ..................................................... 14

2.7.1 A black start ....................................................................................... 14

2.7.2 Disadvantages of Pumped Hydro Storage .......................................... 15

2.8 Europe’s largest Pumped Hydro Storage plant .......................................... 15

2.9 Ireland’s only Pumped Hydro Storage plant ............................................... 15

2.10 Small Case Study on Turlough Hill ............................................................ 16

2.10.1 Environmental Impact ......................................................................... 16

2.10.2 Generating Power .............................................................................. 17

2.10.3 The Reversible Turbine ...................................................................... 17

2.10.4 The Irish electricity grid....................................................................... 18

2.10.5 Hydro Electric Control Centre for Ireland ............................................ 19

2.10.6 How Turlough Hill Controls Ireland’s Hydro Generation ...................... 19

2.11 Pumped Hydro Storage demo (build & control).......................................... 20

2.11.1 Controlling the Process ...................................................................... 20

2.12 The DC generator ...................................................................................... 21

2.13 The Pelton turbine runner .......................................................................... 22

2.14 Programmable Logic Controller ................................................................. 22

2.14.1 The PLC internal components ............................................................ 23

2.15 Supervisory Control and Data Acquisition (SCADA) .................................. 25

2.16 PLC based system .................................................................................... 26

2.17 The importance of variable tags in SCADA ................................................ 27

3 Project finalised design ..................................................................................... 28

3.1 The method of the project .......................................................................... 28

3.1.1 Flow chart of finalised design ............................................................. 29



3.2 Inputs & outputs list (I/O list) ...................................................................... 30

3.3 The PLC ladder program ........................................................................... 31

3.4 The selected components ......................................................................... 34

3.5 PLC wiring diagram ................................................................................... 37

3.6 Material required & costing ........................................................................ 38

4 The build process ............................................................................................. 39

4.1 Creating the upper & lower reservoirs ....................................................... 39

4.2 The movable frame ................................................................................... 40

4.2.1 Constructing the frame ....................................................................... 40

4.3 Attaching the limit switches........................................................................ 41

4.3.1 The actual volume of water in the upper tank ..................................... 41

4.4 The plumbing phase .................................................................................. 42

4.4.1 Editing key areas of plumbing phase .................................................. 43

4.5 Constructing the turbine unit ...................................................................... 44

4.5.1 Testing the generator and attaching all necessary parts ..................... 44

4.6 Electrical Phase......................................................................................... 46

4.6.1 Wiring the control panel & PLC........................................................... 46

4.6.2 Wiring the demo rig’s devices ............................................................. 47

4.7 Installing the serial to USB PLC software .................................................. 49

4.8 Connecting the level sensor ...................................................................... 49

4.9 Supplying the LED load ............................................................................. 51

4.10 The complete build design ......................................................................... 51

4.11 Implementing Citect SCADA...................................................................... 52

4.12 Skills developed & challenges ................................................................... 55

5 Project testing................................................................................................... 56

5.1 Determining the average flow rate ............................................................. 57

5.1.1 Generating efficiency .......................................................................... 57

5.1.2 Energy capacity storage ..................................................................... 58

5.1.3 Pumping efficiency ............................................................................. 58

5.1.4 Overall efficiency of the project........................................................... 58

6 Risk assessment .............................................................................................. 59

7 Conclusion ....................................................................................................... 60

8 References ....................................................................................................... 62

9 Appendices ...................................................................................................... 65

9.1 Appendix A: Irelands Grid Network ............................................................ 65

9.2 Appendix B Material and quotation sheet from MIKO Metals ..................... 66



9.3 Appendix C Solenoid valve data sheet and quotation ................................ 67

9.4 Appendix D The data sheet for Etape level sensor .................................... 70

9.5 Appendix E Information on the water pump ............................................... 72

9.6 Heat merchants quotation ......................................................................... 73

9.7 Appendix F Extra pages in SCADA ........................................................... 73

9.8 Appendix G Meeting minutes ..................................................................... 75

Figure 1: Irelands mixed use of fuel generation ....................................................... 10

Figure 2: A Pumped Hydro Storage Plant in operation ............................................ 11

Figure 3: Ireland’s wave & wind resource ................................................................ 12

Figure 4: Typical graph of the power demand for a day in October .......................... 13

Figure 5: Arial view of Turlough Hill ......................................................................... 16

Figure 6: Reversible Turbine Design ....................................................................... 17

Figure 7: Construction of a Francis Turbine ............................................................. 18

Figure 8: A typical Control System as used in Turlough Hill ..................................... 19

Figure 9: Project design & Equivalent CAD Drawing ................................................ 20

Figure 10: Construction of a DC generator .............................................................. 21

Figure 11: The Pelton turbine runner ....................................................................... 22

Figure 12: Mitsubishi FX2C PLC.............................................................................. 22

Figure 13: FX-4AD Module ...................................................................................... 23

Figure 14: Basic layout of a PLC’s components ....................................................... 23

Figure 15: Internal Opto-isolator .............................................................................. 24

Figure 16: SCADA programming ............................................................................. 25

Figure 17: 5 tasks of SCADA ................................................................................... 25

Figure 18: PLC based SCADA system .................................................................... 26

Figure 19: SCADA graphics ..................................................................................... 27

Figure 20: The submersible water pump .................................................................. 34

Figure 21: Automatic valve Vs manual valve ........................................................... 34

Figure 22: The Milone eTape level sensor ............................................................... 35

Figure 23: The DC generator ................................................................................... 36

Figure 24: The 3 LED’s supplied by generated power ............................................. 36

Figure 25: PLC wiring layout .................................................................................... 37

Figure 26: The FX-4AD wiring diagram .................................................................... 37

Figure 27: Fitted the limit switches ........................................................................... 41

Figure 28: Connecting the valve & the pump ........................................................... 42

Figure 29: Bending & offsetting the pipe work.......................................................... 42

Figure 30: Testing the pump .................................................................................... 42

Figure 31: Making the necessary changes to the penstock ...................................... 43

Figure 32: Fitting a shield over the turbine ............................................................... 43

Figure 33: Making the runner ................................................................................... 44

Figure 34: Attaching all the turbines components .................................................... 44

Figure 35: Turbine in position .................................................................................. 45

Figure 36: Arranging the control panel's components .............................................. 46

Figure 37: Terminating the inputs & outputs ............................................................ 46

Figure 38: Control panel complete ........................................................................... 47



Figure 39: Attaching the trunking & junction box ...................................................... 47

Figure 40 Termination box ....................................................................................... 48

Figure 41: Soldering the connection points .............................................................. 48

Figure 42: Downloading the brain box serial to USB software.................................. 49

Figure 43: Soldering components to a Vero board ................................................... 49

Figure 44: Checking the level sensor works before installation ................................ 50

Figure 45: Securing the level sensor ....................................................................... 50

Figure 46: Checking to see if it is best to wire LED’s in parallel or series ................. 51

Figure 47: The completion of the build ..................................................................... 51

Figure 48: Setting up the users & roles in SCADA ................................................... 52

Figure 49: Setting up clusters and servers ............................................................... 52

Figure 50: Setting up the I/O device ........................................................................ 53

Figure 51: Example of a variable tag (Integer) ......................................................... 53

Figure 52: Building the graphics page...................................................................... 54

Figure 53: The completed graphics page ................................................................. 54

Figure 54: Voltage and current output from the generator........................................ 56

Figure 55: Measuring the average flow rate ............................................................. 57

Table 1: I/O list for the different devices ................................................................... 30

Table 2: Price list for components used ................................................................... 38

Table 3: Risk assessment break down .................................................................... 59



1 Introduction This project was based on the principal of how a Pumped Hydro Storage plant

produces and distributes electricity. A Pumped Hydro Storage plant recycles a

specific volume of water between an upper reservoir and lower reservoir as part of

the process to generate power when needed. This project was designed to convert

the hydraulic potential energy of the water stored in the upper reservoir into

mechanical energy to turn a small DC generator to create electrical energy sufficient

enough to drive a small load. This load represents a consumer requiring power

during specific times of day when power is in high demand, known as peak time

demand. Peak demand is when power is at the best price for the supplier to sell, as

price increases with demand. When off peak time commences, usually late at night

or early morning there is an excess generation of power being produced by power

generation stations and wind farms all around the country with a limited requirement

for power by consumers. Off-peak time is the best time to purchase power, as power

is at a lower tariff rate. This continuously varying demand for power is a key aspect in

the operation of a Pumped Hydro Storage plant and is what led it to be such a

commercial success. In a Pumped Hydro Storage plant the generator that supplies

power at peak time changes into reverse to become a motor (pump) and consumes

power at off-peak time. The motor now pumps water from a lower reservoir back to

an upper reservoir. This process consumes power from the grid at the off peak time

tariff. By understanding the theory of how a Pumped Hydro Storage plant operates, a

small scale Pumped Hydro Storage demo rig was constructed to show how Pumped

Hydro Storage works with a level of control that would be something similar to a real

plant.

This project was chosen because it is a very interesting topic and deserves the

recognition to show the potential it has to be part of the future progression of

renewable energy systems and improving the efficiency of conventional generation

systems. A Pumped Hydro Storage plant has the potential to become a store for

surplus power currently being produced everyday from conventional power

generation plants. A Pumped Hydro Storage plant can become the main hub in a

network to store the over production of energy from other types of renewable sources

that aren’t capable of commercially storing large amounts energy themselves. The

Pumped Hydro Storage demo rig constructed for this project was controlled by a

programmable logic controller (PLC) which helped provide a good learning and

understanding of how to control and fully automate a project very similar to one seen

in industry. The PLC used was a Mitsubishi FX2C. The ladder logic diagram was

created using GX works2 software and transferred to the PLC once complete. The

entire project was mounted on a movable frame with four wheels that lock to give it

stability. This system was fully automated using SCADA to show the entire process

clearly on a computer screen. This report along with the build demonstration and

three presentations at different phases throughout the project will give a clear

understanding of how Pumped Hydro Storage works and how beneficial it can be as

an energy storage facility.



2 Background Information (Research) This section will provide background information relevant to Pumped Hydro Storage.

Research was sought through various different sources and combined together

throughout chapter 2.

2.1 Hydro Power

Hydro power is the conversion of water falling or moving downhill due to gravity into a

useful form of mechanical energy to turn a turbine. The mechanical energy of the

turbine is then converted into electrical energy that gets distributed by transmission

lines. As is normal with every conversion there are losses and factors that will have

an impact on the efficiency which in turn will have an impact on the power output.

The equation listed below shows how the output power can be calculated.

P = Power in Watts

η = Efficiency of the turbine

ρ = The density of water in kilograms per cubic metre

Q = The flow in cubic metres per second

g = The acceleration due to gravity

h = The height difference between inlet and outlet in metres

(Wikipedia, 2014)

Hydropower is a well established, proven technology that has been around for over

100 years and accounts for 90% of all renewable energy sources that contribute to

the world’s energy supplies. Hydroelectricity can give a variable output with the

changing of seasons i.e. more rain in winter than in summer. This means that careful

planning is required in sizing a system to get the maximum output from a selected

turbine (Boyle, 2004).

Pumped Hydro Storage is a form of Hydroelectricity that is unique in the way it

provides a constant controlled output irrelevant of the time of year.



2.2 Why choose Pumped Hydro Storage?

Pumped Hydro Storage is currently the only commercially viable and economic way

of storing large quantities of electrical energy. This makes it extremely important to

the renewable energy sector and to the continual growth of renewable energy in

Ireland. Ireland is a very small country with a lot of natural energy resources at its

disposal. As Ireland is part of the European Union it must comply with some of the

targets set out by Europe to help lower the world’s contribution to climate change by

reducing Carbon emissions. Ireland has identified the generation of electricity by its

many power stations as a key area that needs changing. Ireland has set targets to

supply 40% of its gross electricity demand by renewable energy sources by the year

2020 to meet Europe’s requirements (Boyle, 2004) (Sustainable Energy Authority of

Ireland, 2014).

The concept of having so much of Ireland’s demand for power met by renewable

resources is a massive step in the right direction. The downside however is that

Ireland’s energy resources are highly variable and sometimes the many wind farms

now in operation are not in sync will the Country’s peak load demand. If a wind farm

is not receiving enough energy from the wind to produce the power required, then

power must be sourced elsewhere by other generation stations or indeed a Pumped

Hydro Storage plant. Another key aspect of how Pumped Hydro Storage

compliments wind energy in Ireland is by avoiding curtailment (which is when wind

energy is available to the grid from a wind farm but the grid doesn’t require it and

therefore must be dumped with the wind farm being compensated). A Pumped Hydro

Storage plant plays a pivotal role in avoiding unnecessary costs of curtailment by

being an energy store for Irelands many wind farms that have surplus power

available (Sustainable Energy Authority of Ireland, 2014).

Figure 1: Irelands mixed use of fuel generation

As seen in figure 1, Ireland is heavily dependent on importing fossil fuels to generate

electricity which is costing the economy €6.7 billion annually. Due to this high

dependence, Irish citizens are exposed to prices set by external means in the global

market and can cause a lack of security of supply. Renewable generation in Ireland

has been increasing year on year and in January 2015 wind generation reached

33%, which is one of the highest in the world. However variability is a key factor in

renewable generation when trying to match supply with demand or having to come

up with a means of energy storage. Pumped Hydro Storage is an ideal application to

keep renewable generation in Ireland on the upward trend for the future (Lumcloon

Energy , 2015).



2.3 How Pumped Hydro Storage works

Figure 2: A Pumped Hydro Storage Plant in operation

(Boyle, 2004)

Figure 2 illustrates how a Pumped Hydro Storage plant operates at different times

over the course of a day. A Pumped Hydro Storage plant is a way to store energy. It

consists of two reservoirs, one upper and one lower and a reversible turbine. As seen

in picture B. Power is produced during the day to supply consumer requirements,

known as peak time and is the best time to be generating power because power is at

its most expensive rate to buy. Power is produced by opening the intake gate to allow

the stored potential energy in the water to flow down the penstock and rotate the

turbine that then drives the generator. Most of the energy of the water goes in to

rotating the turbine and then collects in the lower reservoir below.

Picture A shows the operation during the night, which is known as off peak time. This

is the time of day when there is very little demand for power but there is an over

production due to the fossil fuel power stations being run at full output all the time

and due to the variability of the wind farms overproducing with nowhere to store their

surplus power. Off peak time is also when power is at its cheapest rate to purchase

and is the time when a Pumped Hydro Storage plant is most beneficial by changing

its reversible turbine into a pump that now consumes the surplus power readily

available at a reduced cost. The reversible turbine takes the water earlier deposited

in the lower reservoir and returns it back to the upper reservoir to be stored once

again as potential energy. It could be said that a Pumped Hydro Storage plant works

on the same principal as charging a battery. The whole plant is controllable and can

be up and running at full output in a matter of seconds, making it really beneficial to

the electricity grid (Energy Storage Association, 2014) (Boyle, 2004).



2.4 Irelands Potential for Pumped Hydro Storage

Figure 3: Ireland’s wave & wind resource

(Finfacts Ireland, 2011)

Ireland has one of the best wind and wave energy resources in Europe as seen in

figure 3. In particular, off the west coast of Ireland a proposal is currently in the

planning process to build a 1200MW Sea Water Pumped Hydro Storage plant at

Glinsk Mountain near Bellmullet off the North coast of Mayo. There is potential at this

site to generate 25000MW of electricity with combining energy sources from onshore

wind farms, offshore wave farms and the Sea Water Pumped Hydro Storage plant

itself. If this project does go ahead it will create an energy storage hub that will

accept surplus energy from these local energy producing farms and use that energy

to raise sea water from the Atlantic Ocean to the upper reservoir at the top of Glinsk

Mountain. The upper reservoir will have to be excavated to create a manmade lake

out of the boggy land that currently exists there, while the lower reservoir already

exists in the form of the Atlantic Ocean (B.E., James J. Nolan, 2012).

This project is scheduled to be completed by July 2018 and plans to export power to

supply 1.5% of the United Kingdom’s power requirements as well as providing a

much needed upgrading of the electrical infrastructure in the North West of Ireland

(see appendix A). This will create a window of opportunities to connect a network of

renewable energy systems together and help speed up the development of wind

farms near this area that have already received the necessary planning but do not

have the electrical infrastructure to deal with the amount of electricity that will be

generated. The Glinsk Sea Water Pumped Hydro Storage system works by

accepting excess wind power to pump sea water to the upper reservoir on the

mountain. The stored energy can now be used when demand is high or to help the

grid start up its generation power plants if a generation emergency occurs from

adverse weather conditions (Organic Power Ltd, 2014).



2.5 Typical 24hr power demand in Ireland

Figure 4: Typical graph of the power demand for a day in October

(Eirgrid, 2014)

The graph in figure 4 shows the variation in consumer demand for power in Ireland

over a typical day (24th October 2014). It begins at 12:00 A.M were there is 2545MW

of power being consumed. This gradually decreases to the lowest consumption point

of 2110MW at 3:45 A.M. Unfortunately there is excess power being produced at this

time by Ireland’s fossil fuel power plants and wind farms which is not being utilised

due to the lack of demand known as off peak time. It is here that the Pumped Hydro

Storage plant would use that surplus power to supply its reversible turbine to pump

water into the upper reservoir to increase its storage capacity for later use that day.

From 06:00 A.M onwards the demand for power begins to increase and at 08:15 A.M

it rises to 3425MW of power being consumed. This is due to people waking up and

having breakfast before going to work. The power demand remains reasonably

constant until 4:00 P.M were the demand increases rapidly from 3296MW to

3743MW which is a total increase of 447MW in just three hours. It is this sudden

draw on the grids power supply that the Pumped Hydro Storage plant is usually

brought online. The Pumped Hydro Storage plant is hugely beneficial at this time as it

can be up and running at full output in less than one minute meaning that it is an

extremely useful acid to have in cases of sudden spikes in demand.



2.6 Pumped Hydro Storage’s different applications

Pumped Hydro Storage plants can be designed for several different uses. They can

be used only for emergency situations, such as the one in the Catskills Mountains in

the State of New York USA, called the Blenheim-Gilboa Pumped Storage Power

Project. In emergency situations such as damage to the electrical transmission

network caused by bad weather, earth quakes, blackouts or temporary loss of a

particular generating system, this project can be brought on line in the space of two

minutes in the event of any of these disasters occurring (New York Power Authority,

1996-2012).

Pumped Hydro Storage plants can also be used to offset a sudden spike in demand

for power such as Dinorwig in Wales. An everyday day example of a spike like this

happening would be something as simple as a very popular T.V program which

would attract a large audience watching it. When this T.V program cuts to a

commercial or finishes, the people watching usually put on their kettles to make tea.

That could potentially mean millions of kettles turned on simultaneously causing a

huge demand on the generating power plants that supply the network. This is when

having a Pumped Hydro Storage becomes Invaluable as, unlike Coal and Nuclear

Power stations a Pumped Hydro Storage plant can go from a complete standstill to

full load output in a matter of seconds. Although the Pumped Hydro Storage plant

may only have enough water in the upper reservoir to produce electricity for 5 to 6

hours before all that potential energy is exhausted, this time frame is usually

adequate enough to aid the grid dealing with these sudden spike’s in consumer

demand (The GreenAge, 2014).

2.7 Advantages of Pumped Hydro Storage

Pumped Hydro Storage is a relatively inexpensive source of generating electricity as

it doesn’t require fossil fuels for generation. It is a carbon neutral, emission free

renewable energy source that if carefully planned out can have a low environmental

impact. It is fast acting to meet consumer demand and has a controllable output with

a fast response time. In some cases a Pumped Hydro Storage plant can also be

used to help out the supply network in the event of a black start (NHA’s Pumped

Storage Development Council, 2012).

2.7.1 A black start

This is the method taken to recover complete or temporary loss of the power

transmission system which is usually caused by the failure of a power generating

station that is grid tied. This loss failed power station will now be isolated from the

grid and will require an electrical supply to restart. Some power stations do not have

the capability of providing an electrical supply from their own power plant and instead

rely on external means such as diesel generators. A Pumped Hydro Storage plant is

unique as it can keep a reserve of potential energy stored in the upper reservoir to

only use when the event of a black start occurs. This reserve can also be used to

restart a neighbouring power generating plant after the initial problem that forced that

plant to be taken off line has been resolved (The GreenAge, 2014).



2.7.2 Disadvantages of Pumped Hydro Storage

A pumped Hydro Storage plant has a high initial cost because sometimes one or

both reservoirs must be excavated; this can have a severe environmental impact. A

Pumped Hydro Storage plant is site specific because it need’s mountainous areas for

a head height to drop the water. Also the best location for installation is usually

located in remote areas which are far from the main source of the power demand.

Therefore there is a high cost installing the infrastructure because of long and large

transmission lines and electrical equipment. It is also not uncommon for a Pumped

Hydro Storage plant to consume more power than it produces (DUKE ENERGY,

2014).

2.8 Europe’s largest Pumped Hydro Storage plant

In the United Kingdom, Wales has the largest Pumped Hydro Storage plant in

Europe known as Dinorwig. Dinorwig took ten years to complete and is also the

largest man made cavern in Europe. It produces 1728MW of electricity when its six

reversible Francis turbines are in operation. Dinorwig was chosen because of the

naturally occurring high vertical drop between both its reservoirs. This meant a

massive saving on civil works. Dinorwig can go from complete stand still to full

operation in just 12 seconds. This is very significant to the United Kingdom’s grid as it

would take a coal burning power plant or a nuclear power plant at least twelve hours

to reach full output. Dinorwig produces power for a total of five hours and consumes

power for seven hours when the reversible turbines return the water back to the

upper reservoir, meaning that returning the water to the upper reservoir is more

energy intensive than what Dinorwig can produce. Dinorwig consumes 33% more

electricity than it produces. However looking at the bigger picture, the main focus is

to protect the grid’s many power generating stations by meeting the spike in

consumer demand to relieve the stresses on the supply network. Dinorwig more than

compensates for this inefficiency of consuming more than it produces with its fast

reacting response time and guaranteeing everyday controllable on demand electricity

to the United Kingdom’s grid (The GreenAge, 2014).

2.9 Ireland’s only Pumped Hydro Storage plant

In Ireland there is currently only one Pumped Hydro Storage plant in operation called

Turlough Hill located in Co. Wicklow. Turlough hill is owned and operated by the

Electrical Supply Board (ESB).

As seen earlier in section 2.4 there are plans being put in place to try and build

another Pumped Hydro Storage plant located on the west coast of Ireland.



2.10 Small Case Study on Turlough Hill

Figure 5: Arial view of Turlough Hill

Turlough hill was commissioned back in 1974 taking 8 years to complete and costing

22 Million Irish pounds (28 Million Euro). The upper reservoir was artificially made to

produce a storage capacity capable of storing 2.3 Million cubic metres of water.

Turlough hill already has a naturally occurring lake at the bottom of the mountain

called Lough Nahanagan, which was used as the lower reservoir (see figure 5). The

Hydraulic head height separating both these reservoirs is 549 Metres with an

effective head height of 285M to reach the turbines. A large underground chamber

was excavated deep inside the mountain to house the power station. Turlough hill

slightly differs from most other Pumped Hydro Storage plants because the volume of

water travelling in the penstock travels down first before rising up 15M to reach the

turbines. This would result in some friction losses and the loss in effective head

height from 300M to 285M (A.Ter-Gazarian, 2008) (ESB Ireland, 2014).

2.10.1 Environmental Impact

The environmental impact resulting from constructing Turlough hill was kept as low

as possible with some people even referring to it as invisible. This was achieved by

carefully planning and designing the upper reservoir, housing of the turbines, the

generators and the penstock to blend in with the natural surroundings of the Wicklow

mountains (ESB Ireland, 2014).



2.10.2 Generating Power

Turlough hill works on the same principal as any other Pumped Hydro Storage plant

in the way it generates power for consumers at peak time (see figure 2). Turlough hill

has four 73MW generators that are driven by a reversible Francis Turbines. The

generators between them are capable of producing 292MW of power and operate all

year round. Turlough hill is brought online usually around 5pm every day as this has

been identified as the start of Ireland’s peak demand load. The entire generating

process is capable of ramping up to full output in 70 seconds to deliver its 292MW

power constantly for 5 hours to the Irish grid until all of the stored potential energy is

used up (The Irish Times, 2014).

When Turlough hill reaches 5pm, peak time commences and the water residing in

the upper reservoir is released using large sluice gates. Water now falls 285M and

rotates its 4 reversible Francis turbines that in turn rotate the generator to produce

power lasting for 5 hours. Then at off peak time power is supplied from the grid to

reverse the Francis turbine and pump the water back up to the upper reservoir to be

stored for use the following day.

2.10.3 The Reversible Turbine

Figure 6: Reversible Turbine Design

(Eve Cathrin Walset, 2010)

The reversible turbine sits between both reservoirs and is directly coupled to the

generator/ motor as seen in figure 6. The reversible turbine runs in generating mode

when peak demand requires it to produce power. The reversible turbine then

reverses to become a motor to commence pumping mode when off peak demand

requires it to make use of the surplus power being produced on the grid. The most

commonly used reversible turbine is the Francis turbine.



2.10.3.1 The Francis Turbine

Figure 7: Construction of a Francis Turbine

Francis turbines are the best suited turbines for Pumped Hydro Storage. They can be

used in applications with head heights up to 300m. The Francis turbine is a reaction

turbine which means it is completely submerged in water and is enclosed inside a

pressure casing as seen in Figure 7. Water flows in at the inlet of the penstock and

rushes down to the spiral casing which is shaped like a snail’s shell. Inside this

casing is the runner which has specifically designed blades that allow water to flow

over them. This produces a low pressure on one side and a high pressure on the

other side and it is this pressure difference that causes the rotation. The runner is

connected to the generator through a mechanical shaft and this produces the

electricity (Boyle, 2004).

2.10.4 The Irish electricity grid

The Irish electricity grid is currently being operated by Eirgrid’s National Control

Centre (NCC) which is based in Dublin. Eirgrid’s Engineers exercise energy

management and have the task of forecasting an estimating the amount of electricity

that is required at certain times, that following day. It is important that these figures

are as accurate as possible because the load demand can vary without warning.

Therefore a lot of research must be attained on upcoming events such as football

matches and concerts around the country which might cause a change in the

demand that was not foreseen in the records from the previous year. Critical to

Eirgrid’s work are all the power generating stations which are monitored by the

Distribution Control Centres (DCCs) and the Hydro Electric Control Centre which is

located inside in Turlough hill. To monitor all these power generating stations

simultaneously the NCC requires a vast amount of online information. To make this

possible data must be collected by each power station which is achieved by using

Remote Terminal Units (RTUs) that transmit the required information back to Eirgrid

to ensure minute by minute operation of the entire Irish electricity grid (Eirgrid, 2013)

(Energy-Co-operatives Ireland Ltd, 2014).



2.10.5 Hydro Electric Control Centre for Ireland

Turlough hill has a major part to play in the Irish grid as well as being able to respond

quickly to changes in power demand. It is also the centralised hub that controls the 6

major Hydro power plants in Ireland including itself.

2.10.6 How Turlough Hill Controls Ireland’s Hydro Generation

Figure 8: A typical Control System as used in Turlough Hill

Turlough hill has now become the central control centre for all Hydro generation in

Ireland, known as the Hydro Control Centre (HCC). As seen in figure 8, it is a state of

the art control system that has provided improvements in control communication

technology developed in the last 20 years. Turlough hill has to have an operator

present all the time because of its importance to the grid when switching online and

offline as needed. This is one of the main reasons the HCC decided to set up

operations at Turlough hill. This allowed all the other Hydro plants around the

Country such as Cathleen’s falls and Cliff power station in Co. Donegal to only

operate locally on a daily 12 hour shift. These improvements in control engineering

meant at the end of a 12 hour shift the complete control of these Hydro power plants

is handed over to the HCC in Turlough Hill during the night were an operator is

always present anyway. For this level of control to be achieved each independent

Hydro plant that already has an existing level of Supervisory Control and Data

Acquisition (SCADA) present must also hand over their relevant Electronic Dispatch

Information Logging (EDIL) to the HCC in Turlough Hill. This means whenever the

National Control Centre (NCC) sends a command to any one of these Hydro plants it

will always be passed through Turlough Hill first and sent on from here. In the event

of a minor fault occurring at any one of these hydro plants when no operator is

present which is during the night, Turlough Hill’s shift manager can login at home

using a lap top and deal with the fault from there. If a major fault occurs then the

controls are handed back to the local hydro plant immediately and the problem is to

be addressed by staff locally on site (ESB, 2008).



2.11 Pumped Hydro Storage demo (build & control)

This demonstration is based on the principal operation of Pumped Hydro Storage

and due to its small size it was not possible to replicate the same system as the one

being utilised at Turlough hill. The alternative method and the one chosen for this

project is too use a separate pump and turbine. The majority of Pumped Hydro

Storage plants around the world use a sophisticated level of control. This

demonstration will use a programmable logic controller (PLC) to operate all

necessary functions locally from a control panel with all the relevant inputs and

outputs. To further advance this project and make it more realistic supervisory control

and data acquisition (SCADA) was implemented to allow the whole process to be

controlled online by a laptop. SCADA provides a clear visual interface on a computer

screen showing the project operating and what stage it is at, whether it is consuming

or producing power and the level in the upper reservoir. The PLC will control the

process (see figure 9).

2.11.1 Controlling the Process

Figure 9: Project design & Equivalent CAD Drawing

As seen in figure 9, the Computer Aided Design (CAD) drawing shows how the

project is to be controlled. When the water is stored as potential energy in the upper

reservoir, meaning the process is in standby and is waiting for a signal to allow peak

time to commence. This signal is received from a limit switch located in the upper

reservoir whenever the water reaches a specific level. The PLC now tells the

solenoid valve to open and allow water to flow down the penstock to rotate a turbine

and drive a small D.C generator to produce enough power to supply an LED load.

This process continues until all the water is discharged into the lower reservoir. There

will then be a 15 second time delay now to simulate the passing of roughly 6 hours.

This time delay will be provided by a on delay timer located internally in the PLC.

When the timer operates and the limit switch in the lower reservoir is operated

suggesting there is water in the reservoir, then off peak time has commenced and the

pumping process can begin. The pump now activates until all the water has been

returned back to the upper reservoir again.



2.12 The DC generator

A DC generator is an electrical machine that converts mechanical energy into useful

electrical energy in the form of DC voltage and current by using magnetic induction.

The output power produced by the generator depends on the speed of rotation of the

shaft in revs per minute (rpm) and the electrical load that is connected to its output

terminals. A typical application of a DC generator could be a hydro power battery

charging system. The generator’s action is based on Faraday’s law of

electromagnetic induction, which states that an electromotive force (voltage) will be

induced in a conductor when the conductor passes through a varying magnetic field

(Alternative Energy Tutorials, 2013).

Figure 10: Construction of a DC generator

As seen in figure 10 the wire coil (or conductor) is positioned in such a way that when

it is rotated by a turbine for example. The wire coil will rotate and cut through the

magnetic flux which has been set up by the North and South Pole magnets. The

commutator rotates with the wire coil and delivers the voltage to the generator’s

stationary output terminals via two carbon brushes. All DC generators have two parts

called the stator and the rotor. The stator is the part of the generator that is fixed or

stationary and it is the part where the magnetic field is produced. The rotor is the

part of the generator that moves or rotates and is the part where the power

generating coil winding cuts the magnetic flux to produce a voltage (Alternative

Energy Tutorials, 2013).



2.13 The Pelton turbine runner

Figure 11: The Pelton turbine runner

The Pelton turbine is best suited for applications with high head and a low flow rate. It is also a very efficient turbine as it extracts practically all of the energy from the water jet delivered to it and has a very simple design. Water enters the penstock and builds up pressure from a high head. This water then passes through a nozzle known as a spear valve which converts the water under pressure into a high velocity jet. The Pelton turbine’s runner is made up of a number of split buckets which are specifically designed so that the high speed water jet hits them tangentially. Once water makes contact with the split buckets, the notch in the middle of these buckets splits the jet of

water and deflects it back roughly at 180⁰. This is done to prevent the deflected water interfering with the incoming water jet and allows all the water’s energy to go into rotating the runner. The deflected water with zero energy left falls to the discharge channel below. The Pelton turbine is a impulse turbine which means it is free to rotate in air (Moloney, 2013).

2.14 Programmable Logic Controller

Programmable logic controllers (PLC’s) were designed to eliminate the need to

rewire and hard wire in different devices such as relays, timers and counters. A PLC

continuously monitors the state of its inputs and makes a decision based on the

implemented program wrote to it and will decide to turn on or off different output

devices. A PLC has two key advantages; one is it makes it easy to change or

replicate a process and the other is it is modular meaning it is possible to custom

build a PLC to suit a specific application. By using the GX-Works 2 software package

that is designated to Mitsubishi, it is possible to program and reprogram this PLC to

run a sequence of events such as the Pumped Hydro Storage demo rig. There are

two different types of programming languages that can be implemented to cater for

this project’s sequence; either sequential function chart (SFC) or ladder program.

Figure 12 Shows the Mitsubishi

FX2C PLC. This is the PLC that was

used to control the Pumped Hydro

Storage demo rig. The terminals

located on the top are the inputs

which are represented with an X0,

X1 etc. Located on the bottom are

the output terminals which are

represented using y0, y1 etc.

Figure 12: Mitsubishi FX2C PLC



Figure 13: FX-4AD Module

2.14.1 The PLC internal components

(mikroElektronika, 2003)

Figure 14: Basic layout of a PLC’s components

Figure 14 shows that a PC or laptop is required to write a program using the

necessary software and send it to the PLC. It is also useful to put the PC into monitor

mode to see that devices are switching low and high and that any timers or counters

that have been implemented are working properly (Mullen, 2014).

2.14.1.1 The central processing unit (CPU)

The CPU carries out the downloading and uploading of ladder programs and stores

and executes these various programs. The CPU is always in charge of interfacing

with other units in the PLC system such as the input-output circuitry and the memory.

The CPU is also in charge of monitoring in real time the operation of the uploaded

ladder program, it does this by doing checkups for errors. An error is easily detected

by an operator as an error LED will light on the front of the PLC (Mullen, 2014).

Figure 13 shows the Fx-4AD module. This

device attaches to the main PLC via a data

ribbon cable and its sole purpose is to

receive analog signals (0-10V) and convert

them into digital signals (1 or 0). For the

purpose of this project a level sensor

located in the upper tank will send a

variable voltage signal from 0-10V to

channel 2 on the FX-4AD module. It will

then display the level of the water in the

tank on the SCADA graphics screen.



2.14.1.2 Input unit

The input unit enables external input signals from field devices such as switches and

sensors to be hardwired to the PLC’s terminals to then be processed by the CPU.

Inputs can be digital or analog; a digital input is a switch i.e. open or closed (1 or 0)

and an analog input is variable i.e. from 0 to 1 (0-100%). An example of an analog

input would be to measure the variable level in a tank using a level sensor (Mullen,

2014).

2.14.1.3 Output unit

The output unit is connected to externally operated devices such as motors, pumps,

valves etc. Like an input, an output can also be digital i.e. on/off or analog which is 0

to 1. A digital output example would be an indicator lamp and an analog output would

be a motor that can run at various speeds (Mullen, 2014).

2.14.1.4 Power supply unit (PSU)

The PSU in a PLC is supplied directly from a 230V AC supply. The PSU then delivers

5V DC to its own internal electronics and supplies 24V DC to output devices such as

an LED indicator lamp on the control panel’s door. Alternatively, if field devices

require 24V DC or there are a lot of indicators to be supplied, then an external supply

can be used similar to the one chosen for this project (see figure 39)

(PLC System & Applications, 2014).

2.14.1.5 Opto-isolation in a PLC

Figure 15: Internal Opto-isolator

An Opto-isolator is an electronic component that transfers electrical signals from one

circuit to another using light. This is done to prevent high voltages (up to 10kV) that

might have superimposed themselves onto the cable connected to the PLC’s input

terminals causing damage to the CPU. All PLC inputs are isolated by Opto-isolators

to prevent chattering or other forms of electrical noise. The most common type of

Opto-isolator is a combination of an LED shining on to a photo transistor all enclosed

in the same package as seen in figure 15.There are three different types of outputs

that work on this same principal; the relay, the triac and the transistor. The relay is

the most common output and is used to switch DC and AC loads. The triac is used

for switching AC loads at voltages between 85-240V and can switch off fast. The

transistor is used in applications that require the fast switching of DC loads (PLC

System & Applications, 2014).



2.15 Supervisory Control and Data Acquisition (SCADA)

Figure 16: SCADA programming

SCADA is an industrial control system that is utilised in many applications with four

different types of distributed control systems. The power generation industry such as

Turlough hill uses the plant distributed control system (DCS). The HVAC industry

uses the direct digital control system (DDC). Water treatment plants which are

usually very large and spread out, use remote terminal unit based SCADA. The most

common type system and the one used in this project was the PLC based system

(See figure 16). A SCADA system allows total control and monitoring of a plant as

well as the gathering of data to be processed. Also there is direct communication

between the SCADA system and field devices such as level sensors and thermostats

that continually update the information presented on the graphics page. There are

many types of SCADA software and for this project Citect SCADA by Schneider

Electric was used (Inductive Automation, 2014).

Figure 17: 5 tasks of SCADA



There are five tasks that exist in every SCADA system and each one performs a

different process. As seen in figure 17 the display client manages all the data

necessary to be monitored by the operator and any control action that is requested

by that operator. The alarm server manages all the alarms by detecting digital alarm

points as well as comparing the values of analog control points with alarm thresholds.

The report server produces reports from the plants data and these reports can be

triggered by the operator, periodically or event triggered. The trend server collects

the data to be monitored over time. The input/output server is the interface between

the plant floor and the control/monitoring system (SCADA Communications &

Architecture, 2015).

2.16 PLC based system

(Wikipedia, 2015)

Figure 18: PLC based SCADA system

As seen in figure 18 the SCADA system reads the level in the tank from PLC2. PLC 2

will now close the control valve whenever the tank is empty. PLC 1 will now send a

signal to bring on the pump and the flow rate of the fluid being pumped around is

recorded by a flow meter also connected to PLC 1.



(Wikipedia, 2015)

Figure 19: SCADA graphics

Figure 19 shows how a typical SCADA graphics screen would display the devices

seen in figure 18. When building the graphic’s useful prompts to let an operator know

there is a faulty valve can be designed to change the valve’s colour to red. Also a

pump that is healthy and running can be given a colour green. Also in figure 19 the

tank has a slot cut away to expose the fluid inside. The light blue colour is the fluid

and the dark blue colour is the shadow caused by the empty space. It is always

advised to build a nice simple graphics screen with a neutral background and make

sure all the text is clearly visible.

2.17 The importance of variable tags in SCADA

Variable tags are references to memory addresses that are stored in the PLC’s

registers I/O devices. These references are in English and are set up at the start,

once the I/O is determined and before building the graphics begins (SCADA

Communications & Architecture, 2015).



3 Project finalised design Originally this project was designed to be fully automated using both PLC and

SCADA control. However due to the limitations of having to work within a very small

head height and the pressure drop across the solenoid valve was extremely large.

Therefore the force of the water hitting the turbine wasn’t sufficient enough to turn it.

For this reason the solenoid valve was taken out and replaced with a manual gas

level valve. To let the operator know when to open or close this valve a green

indicating lamp was installed on the demo rig to prompt the operator to open when

the lamp is lit and close when the lamp isn’t lit. Initially it was planned to install 3

LEDs that could switch off one by one as the voltage generated decreased due to the

level in the upper reservoir decreasing. However it was decided insted to install three

different coloured LEDs in parallel that would all light at the same time to display the

generated power.

3.1 The method of the project

The demo rig always starts when the upper reservoir is full (Peak time generation).

Therefore by pressing the start button and if the upper limit switch located in the

upper reservoir is activated then manually open the lever valve to start the generation

to produce peak power. Now if the lower limit switch located in the lower reservoir is

activated, turn off the valve and start a 15 second time delay to simulate the change

over from peak to off-peak time. If this time change is complete then the pump turns

on to start the off-peak filling of the upper reservoir. When the upper limit switch is

then reactivated the sequence will restart all over again. This can be seen outlined

clearly in the flow chart below in section 3.1.1.



3.1.1 Flow chart of finalised design

Start Button

Is upper limit

switch

activated?

Is lower limit

switch

activated?

Is the time

delay over?

Open lever valve

Turn off valve and start the

delay on timer

Turn on the pump

Yes

No



3.2 Inputs & outputs list (I/O list)

This is a list that shows the devices used with addresses and a brief description of

what each device does.

Table 1: I/O list for the different devices

Device

Address Tag Name

Action

Start P.B N/O X0 S1 Process starts running (control panel)

Stop P.B N/C X1 S2 Process stops running (control panel)

Start P.B SCADA M16 S1 Process starts running (SCADA)

Stop P.B SCADA M15 S2 Process stops running (SCADA)

Upper limit switch N/O

X2 B1 Indicates upper tank is full

Lower limit switch N/O

X3 B2 Indicates lower tank is full

Lever valve Y1 H1 Releases water to start generating

Pump Y2 H2 Pumps water back up to upper tank

Change over Indicator lamp

Y5 L1 Simulates time delay from peak to off peak-time

Off-Peak time Indicator lamp

Y6 L2 Off peak time has begun start pumping water up

Peak time Indicator lamp

Y7 L3 Peak time has begun start generating power



3.3 The PLC ladder program

The following ladder diagram was drawn up in GX-Works 2.

The first branch consists of three elements in parallel which is the start button on the

control panel (PB Start), the start button on the SCADA screen (SCADA Start) and

the hold on contact from the memory relay. The next elements are the stop button on

the control panel (PB stop) and the stop button on the SCADA screen. If either start

button is activated or none of the stop buttons are activated, then the memory relay

(M8) turns on with a hold on contact.

When the memory relay (m8) is high and both the lower limit switch and pump are

not activated then open the valve and turn on the red peak time indicator lamp.



Again, with M8 high and the lower limit switch has been activated then turn on the

green time delay lamp and start an off-delay timer for 15 seconds. Once timer has

been timed out, turn off the green indicating lamp.

When timer is high and neither the upper limit switch nor the valve is open and M8 is

high, then turn on the pump and the orange off-peak indicator lamp. The pump also

provides a hold on to keep the pumping process going.



This is the code required to allow the PLC to read the variable analog input from the

FX-4AD module. The first part is a cross check for good practice to ensure the

analog module is being read correctly. When M8000 (always 1 when PLC in run

mode) is high, function block K0 is read from BFM K30 in the same function block

and the value is stored in data register D4. This is then compared to check that the

block is an FX-4AD and if so, M1 is turned on. The input channel 2 (CH2) is used in

this project and is selected by writing H3300 to BFM K0 of the FX-4AD. The number

of averaged samples for CH2 is set to 4, by writing 4 to BFM K1 and K2. The

operational status of the FX-4AD is read from BFM K29 and if there are no errors the

value is read from K6, converted into the base units and stored in data register D20.

The value in D20 will continuously vary as the level in the upper tank changes. It is

this value that is used to show the position of the water in the upper reservoir.



3.4 The selected components

There were 5 key devices located on the movable demo rig (See figures 19-23

below). These devices used where small in size but were selected specifically to

operate at the extra low voltage band (2-24VDC). Therefore a 24V power supply was

used to supply the devices on the demo rig itself and the PLC’s own 24V power

supply supplied the lamp indicators on the front door of the panel.

(Ebay, 2014)

Figure 20: The submersible water pump

Figure 21: Automatic valve Vs manual valve

The first design included the solenoid valve, but with the reduced water pressure it

had to be changed for a manual valve. It would have been preferred to use the

solenoid valve but with its design it just didn’t suit this project. The gas valve released

the water at a greater rate and therefore was selected an installed with the down side

of having to open it manually.

Figure 20 shows the small 24V DC

submersible pump that is typically used in

transporting diesel to fill up a car. This

pump has a flow rate of 30L/min (see

appendix E). However for this application it

took over two minutes to pump up 36L

because the pump had to overcome a head

height of 1.2M and a 90 degree bend in the

pipe.



Figure 22: The Milone eTape level sensor

This sensor was vertically installed in the upper reservoir to measure the level. The

water must be allowed to touch both sides of the sensor to allow compression by the

hydrostatic pressure that’s associated with water. This hydrostatic pressure changes

the level sensors resistance which corresponds with the distance from the top of the

sensor to surface of the water. The resistance change is inversely proportional to the

level of the water. The level sensor required a supply of 10V across its 2 inner

terminals and therefore the voltage divider rule was applied to find the correct resistor

(Rref) to put in series to drop the voltage from 24V down to 10V (see figure 22) (see

appendix D).

Level sensor (R2) = 2200Ω

Reference resistor (R1) =?

Supply voltage (Vs) = 24V

Voltage at the analog to digital converter (VADC) = 10V

VADC =

* Vs = 10V=

* 24V

R1 =

= 3080Ω

Therefore a 3300Ω resistor was sufficient.



Figure 23: The DC generator

Figure 24: The 3 LED’s supplied by generated power

The main objective set out at the beginning of this project was to supply a load from a

renewable source. This was achieved by connecting 3 different coloured LEDs in

parallel with each other and connecting them across the generator’s output directly

with no protective resistor required as seen in figure 24.

The small DC generator as seen in figure 23

was one of the most crucial parts in ensuring

the success of this project. It was the output

power of the generator that would make the

decision on the size and type of load that could

be supplied. The generator could supply 2.5V at

a current of 55mA to give an output power

supply of 0.14 Watts. This was a tiny amount of

power but was sufficient enough to light 3 LED’s

for demonstration purposes.



3.5 PLC wiring diagram

Figure 25: PLC wiring layout

Figure 25 shows the layout of the PLC which was drawn up in Auto CAD Electrical.

Located across the top are the inputs and on the bottom are the outputs. Refer to

table 1 for the complete I/O list. A 24V power supplied was used to supply the pump

and the valve (valve indicator lamp) on the demonstration. An emergency stop button

was added to the circuit for safety and once activated; all the outputs are isolated

from supply.

Figure 26: The FX-4AD wiring diagram

Figure 26 shows the FX-4AD module. The

level sensor was connected directly across

both the V+ and Com terminals. A 0V to 10V

signal is then read on channel 2 via the level

sensor and changed to a bit format that is

read by the PLC. The dial was moved to

channel 2 and when the upper reservoir was

full the gain button was pressed and the

corresponding bit value recorded. When the

upper reservoir was empty the offset button

was pressed and that bit value was

recorded. The dial was they moved back to

ready for normal operation. The bit values

where then used in SCADA for the variable

tags (integer) to show the changing level of

the upper reservoir.



3.6 Material required & costing

This was a very important part of the project and after the initial design was agreed

on, a materials list was drawn up to be requested from the college. This was all done

in late December at the very start to avoid delay on parts later on that might have had

an effect on getting the project completed before the deadline. Sourcing these

materials was a good chance to communicate with wholesalers in various types of

industries such as electrical, mechanical and plumbing in order to get quotations for

various parts. Once all quotations were gathered they then had to be signed off by

the supervisor and sent in to the college to try and get the required funding

necessary to purchase these parts. To try and keep within a budget as much as

possible some of the technicians in the college were asked to see if they had any

parts available from previous projects. This worked well as only some parts of this

project had to be sourced from outside the college which helped reduce the cost and

meant work could start right away. A full list of these items can be seen in table 2

below with some quotations in the appendix.

Table 2: Price list for components used

Item Use Source Price (€)

Metal The frame Miko Metals 135

Pump Pumping water Ebay 10

Solenoid valve Releasing water RS Radionics 68

Gas valve Replacing solenoid valve Woodies DIY 10

Water butt 2 Reservoirs Shannon Airport 10

Piping and fittings Distribute water Heat Merchants 40

DC Motor Generator Home 0

Turbine Spinning the generator Amazon 8

Limit switches Switching on/off pump College 0

Level sensor Measuring tank level College 30

Control panel Controlling the project College 0

Control panel’s parts Operating the demo College 0



4 The build process After carrying out some detailed research to gain knowledge about the background of

Pumped Hydro Storage, it was now time to put a clear outlined plan into effect by

building a movable demonstration rig.

Figure 27: Making the upper & lower reservoir

4.1 Creating the upper & lower reservoirs

After a lot of searching the internet for tanks that would be a suitable choice for the

reservoirs at a reasonable price, it was discovered that the best fit was to buy a 55

gallon water butt that was sealed at both ends and cut it in half. This was purchased

for 10 euro, which saved a portion of the budget that could be used else were in the

project. The tanks were cut in half using a grinder which left a nice smooth finish (see

figure 27).

Figure 28: Tanks fitted

The tank’s dimensions were 23 inches wide by 35

inches high. Therefore cutting the tank in half would

in theory allow a storage capacity of 22.5 gallons or

85 litres of water. In a rough estimate done previous

a tank with a capacity of 60 litres would have been

enough to simulate power generation for 1 minute

(1L/S flow rate). The completed demonstration is

intended to be stored away for later use in future

years; therefore it required a way of draining the

water down after use. As seen in figure 27 there are

2 threaded bungs at the bottom of the tank that can

be opened to allow water to escape out in a short

period of time. Therefore for this reason that

particular tank was chosen for the lower reservoir

and placed at the bottom. Figure 28 shows the

completed frame with the tanks fitted in position.



4.2 The movable frame

This next part of the build was to construct a solid and sturdy movable frame that

would allow the demonstration to carry all the weight from the water residing in the

upper tank. It had a specific height restriction so that it could fit through an average

door frame. Choosing the frames height however was a trade-off which meant that

for safety and for practicality of demonstrating the head height was kept to a

minimum, which therefore meant that power generation was reduced.

4.2.1 Constructing the frame

Figure 28: Assembling the frame

As seen in figure 28, the frame was assembled from 25mm aluminium box which was

purchased from Mico Metals in Co. Cork (see appendix B). The wheels for the project

where salvaged from a previous project that the college had in storage. The frame

had to be made to a specific size to allow for the diameter of the rounded tank to fit

into place. Once all pieces were cut and filed, it was then a matter of attaching the

plastic inserts and slotting all the pieces in to their correct positions. To prevent any

dents or damage to the frame a mallet was the best tool for assembling. The

brackets used to support both tanks in position were also fitted at this stage using a

cordless drill and a ratchet set.



4.3 Attaching the limit switches

The limit switches used were basic extra low voltage 24V normally open contacts.

When the water reaches the required level the limit switches contact changes state

and closes. This action will now input a signal to the PLC to take a course of action. If

the upper limit switch activates the pump turns off as the required level has been

reached. If the lower limit switch has been activated then the valve shuts off as the

correct volume of water has been released from the upper reservoir. Neither of these

limit switches will be operated at the same time.

Figure 27: Fitted the limit switches

As also mentioned in section 4.1, the level of the water is a key factor in the

demonstration with regards to simulation time. Roughly estimating for a flow rate of

1L/S then the tank needs a storage capacity of 60 litres so it can deliver water to the

turbine for 1 minute (60 seconds). Also to allow the demonstration to be moved

around without spilling any water the limit switches were fitted at 12 inches in height

to achieve the 60 litres but also give a clearance of 7.5 inches from the surface of the

water to the rim of the tank (see figure 27).

Half tank = 85 litres @ a height of 17.5 inches

Therefore for 1 inch in height =

= 4.86L/Inch

Height of 60 litres =

= 12.34 Inches

4.3.1 The actual volume of water in the upper tank

A revised plan was done on the upper reservoir because instead of an average flow

rate of 1L/S as was initially estimated the best that could be gained from the rig was

0.3L/S. Therefore the upper limit switch was moved down from 12.34 inches to 7.5

inches which allowed 36L to reside in the upper reservoir.



4.4 The plumbing phase

There was a certain amount of plumbing required for this project. Once the tanks

were fitted in place the plumbing phase could begin.

Figure 28: Connecting the valve & the pump

As seen in figure 28, the first part was to bore a hole at the bottom of the tank. A

stepped cone cutter was used with a lot of care to ensure the hole was not drilled out

too big for the fitting. The copper inserts were then installed for the valve and the

pump was attached to a flexible pipe and held in position using a jubilee clip.

Figure 29: Bending & offsetting the pipe work

Figure 30: Testing the pump

Figure 29 shows how the copper pipe was bent. This

was the pipe that was required to return the water back

to the upper reservoir. At one end a 90 degree swan

neck bend was formed and at the opposite end there

was a 30 degree off set. The offset allowed the pipe to

be placed inside the lower reservoir so the flexible pipe

could be attached to it. This was done in case the

flexible pipe became detached during operation,

causing a leak. Figure 30 shows a quick test carried out

on the pump before it was fitted and it emptied a basin

of water in 3 seconds proving it was more that capable

for the job of pumping up 1.2M.



4.4.1 Editing key areas of plumbing phase

The original plumbing phase had to be edited due to the solenoid valve failing to

allow the water through at a flow rate that was sufficient enough to turn the turbines

runner (see appendix C).

Figure 31: Making the necessary changes to the penstock

As seen in figure 31, the first change that was made was to increase the size of the

copper pipe from ½ inch to ¾ inch. Then the solenoid valve was taking out and

replaced with a gas lever valve. The lever valve unfortunately had to be manually

operated but had the advantage of allowing the flow rate to be increased from

negligible to 0.3 litres per second. Also as an added improvement an end nozzle

reducer was fitted to increase the velocity of the water hitting the turbines runner.

Figure 32: Fitting a shield over the turbine

With the increase in velocity helped by the nozzle, the water was then reflecting back

of the runner and was splashing out on to the floor which caused a slipping hazard.

Therefore as seen in figure 32 a Perspex shield angled a 45 degrees was attached to

prevent this from happening.



4.5 Constructing the turbine unit

This was undoubtedly the most ambitious and challenging part of the project. The

size restriction on this demonstration meant it was difficult to find a suitable runner

that could be attached to the generator to create power. Therefore after careful

consideration it was decided that an edited homemade version of a Pelton turbine

was the most suitable for a generator of this size.

Figure 33: Making the runner

The runner was created using 2 fan blades as seen in figure 33. These fan blades

are usually attached to the shaft of a 3 phase motor for cooling purposes. Although

both these blades were purchased on line from the same manufacturer the slots in

the centre bore-hole of each one did not match up exactly with each other. After

some delicate drilling and filing this problem was resolved and the blades were super

glued together to make the complete runner. The runner created was more like a

paddle wheel and does not resemble a regular Pelton turbine blade that has a

special curve like design as seen in figure 11.

4.5.1 Testing the generator and attaching all necessary parts

Figure 34: Attaching all the turbines components



To find the correct DC generator to use was a matter of trial an error. As seen in

figure 34, the picture on the left shows a test carried out using an 18 V cordless drill

in first gear to mimic the speed that the turbine’s runner would be rotating at. The DC

generator was normally used as a DC motor that changed electrical energy into

mechanical energy. If that process is reversed by attaching a runner to the motors

shaft to spin it in reverse, then mechanical energy will be converted into electrical

energy.

There was 2 motors tested; the first motor selected had a rated speed of 500rpm and

was normally used to open and close window blinds, meaning it required more torque

at less speed. This motor when run in reverse by the drill only delivered 0.5V,

meaning it was not suitable and was left to one side. The next DC motor was

removed from a toy car and had a rated speed of 2000rpm with very little torque,

which became clear as the shaft was very easily turned, even by hand. When put to

the same test using the drill, this motor in reverse achieved 6V and therefore was the

most suitable motor to use as a generator for the project.

In figure 34, the picture in the centre shows all the components that were required in

attaching the runner to the DC generator. The extension piece required to connect

the generator shaft to the turbine’s runner was machined using one of the lathes in

the college. This rotation was made possible using a bearing which was housed in a

solid aluminium bar and can also be seen in the centre picture above.

Figure 35: Turbine in position

The turbine and generator was

then attached to a bracket which

was also made from aluminium as

seen in figure 35. The entire unit

was placed in the demonstration

and ready for the real test using

water. Aluminium was the metal

mainly used as it is much lighter

than mild steel.



4.6 Electrical Phase

Before the wiring process could begin it was important to have a clear understanding

of how many inputs and outputs are required in the project, their voltages and how

they are to be wired. Therefore the first step was to draw up an electrical plan in Auto

CAD electrical (See figure 25).

4.6.1 Wiring the control panel & PLC

Once the control panel and all the necessary components were sourced it was time

to start putting everything into place. For the size of the panel 2 rows was all that

could be used.

Figure 36: Arranging the control panel's components

The first step was to install the din rail and cable trunking. Then for best fit the 24V

PSU, PLC and the FX-4AD module were installed on the top row. On the second row

an isolator, control fuse and the required amount of terminal blocks were fitted. The

last part before the wiring could start was to drill out the holes on the control panel’s

door for the 2 push buttons, the emergency stop button and the 3 indicator lamps

shown in figure 36.

Figure 37: Terminating the inputs & outputs

As seen in figure 37, for best practice and to allow easy traceability each terminal

block was labelled with its correct I/O tag. The cable used was single core 0.75mm2.

The red cable was used for 24V and the black cable was used for 0V. The end of

each cable was paired off using a snips and a boot laced Ferrell was crimped to

allow a good safe termination.



Figure 38: Control panel complete

The control panel could now be fixed in its permanent position to make it easier to

work on and for displaying when it came to demonstration time at the end.

4.6.2 Wiring the demo rig’s devices

Figure 39: Attaching the trunking & junction box

On the demonstration’s frame as seen in figure 39, each frame was 25mm wide,

which meant 25mm PVC trunking fitted perfectly and provided adequate protection

for the cables brought out to each device. The original plan was to mount the control

panel directly to the movable frame which would have caused an unbalance due to

excess weight on one side. Therefore it was just fixed to the wall in the work shop.

Figure 38 shows the control panel

completely wired with the PLC’s

inputs and outputs and the analog

module’s inputs all connected to

their designated terminal blocks. The

next stage was to start wiring from

the control panels terminal blocks to

the inputs and outputs located on

the demo rig.



Figure 40 Termination box

Figure 41: Soldering the connection points

In figure 41, the picture on the left shows a female serial point before it was soldered.

The picture in the middle shows the wires being soldered in to each of the different

slots. This was very tedious, precise work and it was found that attaching the male

lead to hold things in place made it easier to get a good soldered termination. The

picture on the right shows the finished connection. All that had to be done now was

attach another female serial point on the control panel and make sure the numbers

on both of these points correspond with each other. This meant that the demo rig

was now portable, as the only link between the rig and control panel was through a

detachable serial cable.

An 8X6 inch junction box was fixed to the corner

of the frame. A small piece of din rail was then

fitted to the inside of the box to allow the terminal

blocks to fit securely in place. A slot was then cut

out of the 25mm trunking that ran across the top

of the box to allow cables inside to be terminated.

As seen in figure 40 a female serial connection

point was also drilled out and fitted to allow

connection between the junction box and the

control panel.



4.7 Installing the serial to USB PLC software

With the demonstration now wired down as far as the level sensor and LEDs it was

now time to upload the necessary software that would allow communication between

the PLC and the laptop. This would also prove very useful in testing what was done

so far and in calibrating the level sensor later on.

Figure 42: Downloading the brain box serial to USB software

As seen in figure 42 the software used was the Brain box serial to USB. The first part

was to install the software on the lap using a CD. Then when prompted insert the

USB to serial converter and once recognised by the laptop, the CD could be

removed. The ladder program could now be written and exported to the PLC through

Com 4 on the lab tops control panel.

4.8 Connecting the level sensor

Before the level sensor could be attached to the FX-4AD, some electronic circuitry

had to be put in place.

Figure 43: Soldering components to a Vero board

The middle picture in figure 43 shows a 3300Ω resistor in series with a test resistor.

The test resistor was to simulate a resistance value typical to the level sensor. Once

everything was soldered in position the test resistor was removed and replaced by 2

leads that were brought up to the level sensor in the upper reservoir. As seen in the

picture on the right, the same leads that were connected across the two inner

terminals of the level sensor where also the leads that would isplay the variable

voltage value (0-10V) across the FX-4AD converter.



Figure 44: Checking the level sensor works before installation

By simply half submerging the level sensor in water it could be seen clearly that the

voltage dropped from 10V to 6V as seen on the volt meter in figure 47. This was

consistent with the spec sheet (See appendix D) and therefore the level sensor was

installed in the upper reservoir.

Figure 45: Securing the level sensor

Initially as seen in figure 45 the picture on the left shows how the level sensor was

set up against a strip of plastic PVC trunking to allow the water to make contact with

both sides of the level sensor. However this did not work for two reasons. Firstly the

sensor was touching the trunking which gave a false reading of the depth of the

water and secondly the water being delivered back up by the pump caused a large

disturbance on the surface of the water which contributed to an unstable reading.

Therefore as seen in the picture on the right it was decided to install the level sensor

inside a waste pipe which had holes drilled in its sides to keep the surface

fluctuations to a minimum.



4.9 Supplying the LED load

The most rewarding part of the project was to see if a useable power output could be

delivered by the generator to supply a small load that would symbolise a consumer’s

power requirement. This was achieved by using 3 standard LED’s that switch on

between 1.9V and 2.1V, at a current of 20mA.

Figure 46: Checking to see if it is best to wire LED’s in parallel or series

Before the 3 LED’s were fitted in their housing on the demo rig it was important to

figure out the best way to wire them, either in series or parallel. As seen in figure 46,

wiring the LED’s in series meant only one shone brightly, whereas in parallel they all

lit but one was dimmer than the other two. Therefore it was chosen to wire them in

parallel.

4.10 The complete build design

Figure 47: The completion of the build

Figure 47 shows the completed project and control panel mounted upright on the

wall. Everything was now in position, working and ready for demonstrating.



4.11 Implementing Citect SCADA

When using Citect SCADA to monitor and control this demo rig it was very important

to set up the project properly from the very beginning.

Figure 48: Setting up the users & roles in SCADA

This part was setting up the role of the user (Engineer) and choosing which area they

can access (global privileges). It is also a requirement to set up a password at this

stage as seen in figure 48.

Figure 49: Setting up clusters and servers

In this part a cluster (project) was set up which required a name “hydro” as seen in

figure 49. Included in this cluster was three servers called alarm, report and trend

(see figure 17). It is important not to include the I/O server at this stage.



Figure 50: Setting up the I/O device

To set up the I/O device navigation must be made through the set up wizard first, to

choose the stand alone option. Then under communications, using the express

wizard the option for external I/O device was selected to allow communication via the

PC as seen in figure 50.

Figure 51: Example of a variable tag (Integer)

This was a very important step because it was assigning specific names to variable

tags in the project for later use when designing the graphic’s page. The tag for the

level sensor (analog) as seen in figure 51 was different to all the other tags which are

digital. The raw zero scale value represents the bits read from the PLC in monitor

mode via the FX-AD4 and corresponds to an empty tank (Eng Zero Scale = 0 %).

The raw full scale value was also read at -320 bits and corresponds to a full tank

(Eng Full Scale 100%). After the 10 records were completed, it was time to pack and

compile.



Figure 52: Building the graphics page

This was the part where each component was addressed with a variable tag selected

earlier in (see figure 51). It is always good practice to select the tag from the drop

down menu instead of typing it in because any change i.e. a change of spelling would

result in the tag required not being detected. Figure 52 also shows the part where the

animated text and different colours for devices (off/on, grey/green) are set up.

Figure 53: The completed graphics page

Figure 53 shows the completed graphics page showing the demo rig and control

panel. This page was kept as close to the real project as possible. The level in the

upper reservoir varies as the level in the real rig varies. The demo rig can be

controlled and monitored using this page. Login can also be done here.



4.12 Skills developed & challenges

When completing the building of this project there where many aspects that provided

many challenges and trade-offs to make things work. There were many skills

developed that supported the theory learned during the course of the year. For

example, the PLC and SCADA programming was extremely beneficial to see how

they can both be applied to a real application. Using the voltage divider law to find

the correct value of a resistor and then installing that resistor to make the level

sensor work was also nice to see in a real application. How the analog to digital

converter operates was a difficult part to understand from reading but when seeing it

in real life and to program and manipulate it to do a certain task made the operation

much clearer to understand. A lot of perseverance was required for this project

because of how ambitious it was to implement on such a small scale. The minute

meetings (see appendix G) were a vital part of learning because it gave a chance to

express any concerns and seek advice from the supervisor.

The learning achieved in SCADA was very beneficial in regards to the plant

information systems module. Extra pages where set up in SCADA such as an alarm

page, overview page, trend page and a hardware page. Also for added security

anyone wanting to run or change things to the graphics in this project had to login

with a user name and password and depending on the role name provided only

certain parameters were available to be changed (see appendix F).



5 Project testing This was the part of the project that tested and analysed everything that was

undertaken so far. The main aim of this project was to deliver generated power from

a renewable source. Through a series of tests it was proved that a very small voltage

and current was generated.

Figure 54: Voltage and current output from the generator

As seen in figure 54 the voltage output from the generator was 2.5V with a current of

55mA. Therefore the power produced was 0.14W.

Power (W) = Voltage (V) * Current (A)

2.5V * 0.055A = 0.14W



5.1 Determining the average flow rate

Figure 55: Measuring the average flow rate

The very first step as seen in figure 55 was to fill the lower reservoir until the lower

limit switch was activated. There was enough water now in the lower reservoir not to

impede the turbines runner from spinning but also enough water in the lower

reservoir to keep the pump from running dry. This was because the upper limit switch

in the upper reservoir always operates before this can happen. It is this volume of

water that will determine the flow rate. The middle picture shows a water drum with a

maximum known volume of 10 litres of water with a minimum of 1 litre. The water

drum was placed under the pipe in the upper reservoir with all the water residing in

the lower reservoir.

The pump was then turned on until the water drum was filled with 10 litres of water

and emptied into the upper reservoir with the valve held shut. This process was

repeated until the correct volume of water was extracted from the lower to the upper

reservoir. It took 3.6 drums which meant a volume of 36 litres was recycled between

these reservoirs. The valve was then opened to release the water back down and

using a stop watch it was found that it took 2 minutes (120 seconds) to empty the 36

litres. Therefore this meant that every second 0.3 litres of water was leaving the tank

and this could be used as the average flow rate.

5.1.1 Generating efficiency

P = ƞ*Q*h*g

Flow rate (Q) = 0.3L/s = 0.3Kg/s

Output power (POUT) = 0.14W

Head height (h) = 0.9M

Acceleration due to gravity (g) = 9.81M/S2

Efficiency ( ) =?

ȠGENERATING =

=

= 5.3% efficient



5.1.2 Energy capacity storage

Energy capacity storage is the amount of potential energy stored in the upper

reservoir, which is set by the mass of the water stored there.

E = ƞGEN*M*h*g

Energy capacity (E) =?

Generator efficiency (ƞGEN) = 5.3%

Mass of water (M) = 36Kg

Head height (h)

Acceleration due to gravity (g) = 9.81 M/S2

E = 0.053*36kg*0.9M*9.81 M/S2 = 16.81Joules

5.1.3 Pumping efficiency

This efficiency is due to the energy lost in pumping the water back up.

ȠPUMPING =

=

* 100 = 0.4%

5.1.4 Overall efficiency of the project

This is the efficiency of the entire project and is the product of both the pumping and

generating efficiencies.

ȠOVERALL = ȠGENERATING * ȠPUMPING

ȠOVERALL = 5.3% * 0.4% = 2.12%

This is a really poor efficiency and in no way shape or form is directly related to the

efficiency of a typical Pumped Hydro Storage plant that could have efficiency greater

that 80%. However it was very useful to have this demonstration to allow these

calculations to be performed in such a practical way.



6 Risk assessment Table 3: Risk assessment break down

Hazard Risk Po

ssib

ility

Imp

act

Ris

k

facto

r

Actions to minimise risks New

risk

factor

Electric

power

tools

Electrocution 2 4 6 1. Electrical equipment must always be

operated correctly.

2. Additional help sought especially when

using unfamiliar equipment such as the

lathe.

3. Avoid contact of electrical devices with

water.

4. Eye protection must be worn.

5

Physical

injury

3 4 7 6

Fire Burns 1 4 5 1. Equipment should be switched off when

not in use for long periods.

2. System should be properly earthed.

3. Use extra low voltage devices.

5

Hand

tools

Physical

injury

4 3 7 1. Correct usage demonstrated by a

competent person

2. Used only as manufactures instruction

state.

3. Only use the proper tool safely.

6

Slips

and

trips

Physical

injury

2 4 6 1. Any water spillages should be cleaned up

immediately.

2. Any hazards such as trailing cables going to the demo rig should be properly signed.

3. The demo rig should be stored away safely in the workshop away from other student’s normal walkways.

4

As this is a small demonstration operating at extra low voltages the risks are very

low. However some small risks do apply especially slips and trips. Hopefully this

small risk assessment will prevent such events occurring.

Hazard – Physical nature of the hazard.

Risk – The outcome of something negative happening.

Possibility – Probability of hazard occurring (1=very unlikely & 5=very possible).

Impact – Result of possible risk. 1=minor injury requiring some basic first aid and 5

resulting in death.

Current risk factor – This is an accumulation of the impact (1-5) and the likelihood

(1-5) and is scaled from 1 -10 (1=lowest and 10=highest).

Actions to minimise risk – The corrective measures taken to prevent the hazard

and therefore reduce the risk.

New risk factor – The new risk factor for a hazard when corrective measures have

been taken.



7 Conclusion This project was a success as it met the key goal which was to generate power from

a renewable source to supply a small load similar to that of a real Pumped Hydro

Storage plant supplying consumers on the grid. There were many steps taking in

order to achieve this goal. Firstly some extensive research into how a regular

Pumped Hydro Storage plant operates i.e. the pumping and generating processes

etc. Then a detailed plan was drawn up of how the demo was going to be built and

what components were going to be used. Any components that couldn’t be sourced

within the college were ordered from suppliers.

The build phase then started with cutting a water butt in half to make the two

reservoirs and then building the frame around them. The next phase was the

plumbing phase which initially didn’t work out because the solenoid valve wasn’t

letting the water down fast enough to turn the turbine. This problem was fixed by

using a gas lever valve as a replacement valve, but this now meant that the demo rig

was no longer fully automated because the lever valve had to be manually opened.

There were some concerns about the pump not being strong enough to recycle the

water between the two reservoirs but after testing, it proved sufficient. The next part

was to wire the control panel. It was here there was uncertainty about attaching the

control panel to the movable frame because of its size and weight. Therefore the

frame was wired specifically to become detachable and the panel was fixed to a wall

in the work shop instead.

The PLC program was written and downloaded at this stage and communication was

set up between the PLC and the laptop. It was then time to make the runner for the

turbine unit. It was not an easy task to replicate a Francis turbine to operate with a

demo of this size. Therefore the runner was made from two cooling fan blades that

were glued together to resemble similar features of a Pelton turbine. It was later

realized that this contributed to a very low generator efficiency. The small DC motor

worked surprisingly well as a generator by giving a voltage output of 2.5V DC. This

voltage was sufficient enough to power a very small load consisting of three LEDS

wired in parallel. The generator now had a fixed load which meant the generators

power output could be found by finding the current it draws multiplied by the voltage

supplied. A few more calculations were then performed to work out various other

efficiencies. A level sensor was then installed in the upper reservoir to give an

indication of the variable level caused by water being released and returned in each

cycle. There were some problems here in getting the sensor to stabilize to see the

readings it displayed for a full tank and an empty tank. These readings were then

used in SCADA when setting up the level sensor’s variable tags. SCADA was the

very last part of this project and it made all the difference when it came to

demonstrating the project as it really made it look professional especially showing the

varying level in the upper reservoir that was matching the reservoir on the SCADA

graphics page.

Through the entire project there were a number of problems encountered. These

problems were mainly due to the size restrictions imposed on the demo rig and

keeping within a strict budget for materials. Pumped Hydro Storage is not really



viable below a commercial level and trying to keep this project as close to the real

thing as possible was really difficult. For example, the head height that the water

dropped from was less than one metre which severely restricted the output from the

generator. Also, size restriction meant that a turbine and pump with two separate

pipes had to be used instead of a reversible pump turbine with one pipe, which would

be found in a real application. The level sensor was relatively cheap and was very

unstable and once installed initially it gave false readings due to the surface ripple

caused by the water being returned to the upper reservoir by the pump. This problem

was fixed by inserting the level sensor in a waste pipe that had holes to allow water

in at a low disturbance. When fitting the upper limit switch it was not taking into

account to leave enough water in the lower reservoir to cover the pump to prevent

the pump running dry. Therefore the upper limit switch had to be lowered which left

an unnecessary hole in the upper reservoir.

Over all the project was successful but there was a number things that would made it

better, if there was sufficient time. The DC generator and turbine would have the

potential to generate more power should an improved design be done. The 2.5V DC

output from the generator was supplying the 3 LEDS in parallel could also be

improved. This is an area that could have been brought to a more advanced stage by

using electronics to increase the 2.5V output up to 8V. This 8V would then supply 8

Zener diodes that would turn of as the voltage dropped by 1V operating from 1-8V.

As the level in the upper reservoir drops the output would drop from 8-1V, meaning

the switching off of all 8 LEDs one by one simultaneously as level drops. This would

be an excellent way of displaying how lowering the head height decreases power.

However this was not able to be done with only 2.5V without this circuitry and again

time was a factor.

This project was very challenging and worth all the effort and time that was put into it

because it complimented a lot of the skills and knowledge developed over the course

of this renewable and electrical energy systems degree. After the final demonstration

the Pumped Hydro Storage rig was safely stored away in the college and will

hopefully be a useful asset to the lectures when explaining the concept of Pumped

Hydro Storage to future students.

Pumped Hydro Storage is a method that is going to be seen a lot more in the future

as it is currently the only commercially viable way of storing large amounts of energy

and presently accounts for over 100GW of the world’s generating capacity. As power

generation from renewable energy continues to grow there will also be an increase in

the need to store energy to meet consumer demand. This is another reason this

project was chosen as it highlights and explains the need for more Pumped Hydro

Storage plants to be developed in the future to help continue and further advance the

effort in preventing climate change by reducing green house gas emissions being

released into the Earths atmosphere.



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PLC System & Applications (2014) Ed Mullen.

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Available at:

http://www.promotic.eu/en/firm/reference/detail/detail/ingea/kninicky/kninicky.htm


SCADA Communications & Architecture (2015) Ed Mullen.

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Available at: http://www.seai.ie/Energy-Data-Portal/Frequently-Asked-

Questions/Energy_Targets_FAQ/




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Available at: http://www.irishtimes.com/news/ireland/irish-news/esb-offers-free-tours-

of-turlough-hill-hydro-station-1.1850809


Turlough Hill Power Station, 2014. Wikipedia, the free encyclopedia. [Online]

Available at: http://en.wikipedia.org/wiki/Turlough_Hill_Power_Station


Wikipedia, 2014. Hydro Power. [Online]

Available at: http://en.wikipedia.org/wiki/Hydropower


Wikipedia, 2014. Solenoid valve. [Online]

Available at: http://en.wikipedia.org/wiki/Solenoid_valve


Wikipedia, 2015. SCADA. [Online]

Available at: http://en.wikipedia.org/wiki/SCADA

[Accessed 27 March 2015].



9 Appendices

9.1 Appendix A: Irelands Grid Network



9.2 Appendix B Material and quotation sheet from MIKO Metals



9.3 Appendix C Solenoid valve data sheet and quotation



9.4 Appendix D The data sheet for Etape level sensor



9.5 Appendix E Information on the water pump



9.6 Heat merchants quotation

9.7 Appendix F Extra pages in SCADA



9.8 Appendix G Meeting minutes

Project Meeting Minutes 1

Student: Steven Sweeney Date: 07/10/14

Project Title: Pumped Hydro Demo

Tasks from Last meeting:

To submit the project proposal form stating clearly what the project is to

demonstrate and four objectives that aiming to be achieved.

Progress since Last meeting:

Project proposal form was submitted on moodle along with the name of the

Supervisor overseeing the project. A rough idea of how the project is going to

be built was drawn up to see how the best to lay out items was being used.

Tasks for next meeting:

Redesign the first drawing to include some new ideas that were discussed in

this meeting and also to draw up a materials list to give to Alan Kennedy to

start getting some parts ordered.

Student: S. Sweeney Supervisor: Ed Mullen Date: 09/10/14







To make a list of material needed for ordering. Too decide on the final

design for the project.


The material list is complete and is ready to submit to Alan Kennedy for

approval and signature of my supervisor.


Submit the list to Alan and get the material ordered. Start building the

frame of the project and source two tanks that will each hold the required

volume of water.








Submitting the material list for clearance. Source to suitable tanks for the

reservoirs and start building the frame.


Half the frame is built with one of the tanks in place. The other part of the

frame has been ordered.


Continue with the research. Finalize the presentation and prepare for the

first interview.







Tasks from Last meeting: Continuing with the research and getting ready for the first interview.


Completed the first interview in front of three lecturers and received

feedback on the project. Made a good start on the research chapter and

submitted some what was done so far to the supervisor for reviewing. The

metal for the top half of the frame arrived from Miko Metals.

Tasks for next meeting: Discuss the direction the research chapter is taken and the format of the

report including images, references and the style of writing.







Tasks from Last meeting: Discuss the direction the research chapter is taken and the format of the

report including images, references and the style of writing.

Progress since Last meeting: Decided to include a small case study on Irelands Pumped Hydro Storage

plant; Turlough Hill.

Tasks for next meeting: Get as much of the research chapter completed as possible on Friday 05

of December and use the following Friday to do any tidying up required.







Tasks from Last meeting: Completed and submitted the research chapter before the dead line. Also

had to prepared and gather all relevant material needed to start

constructing the project.

Progress since Last meeting: Had started completing the aluminum frame and starting building the

control panel which included a PLC, PSU, Analogue converter, indicating

lamps and all relevant terminal blocks.

Tasks for next meeting: Finish the frame and set the tanks in place. Do the necessary plumbing

and figure out the best position for level sensors. Start to wire the control

panel and start communicating with the PLC and down loading software

to a lap top. Glue the cooling fans together to create the runner for the

turbine.







Tasks from Last meeting: Complete the frame. Down load PLC software and write some test

programs. Start wiring the control panel and start installing the piping

and solenoid valve. Glue the runner to make one piece.

Progress since Last meeting: Piping cannot be completed with a bender and slides and none available

in college. PLC is communicating fine and the control panel is nearly

complete down to figuring out how to attach the level sensor in the upper

tank. Runner was successfully glued together at the right angles.

Tasks for next meeting: Figure out how to house the level sensor and the required circuitry.

Figure out how to attach the turbine to the generator and how to keep the

generator dry. Source a pipe bender.








Figure out how to house the level sensor and the required circuitry.

Figure out how to attach the turbine to the generator and how to keep the

generator dry. Source a pipe bender.


Borrowed a pipe bender from a lecturer in the college and completed all

the pipe work. Fitted the level sensor in place in such a way that water

could be in contact with both sides as was required on the spec sheet.


Program the analog module to read the level in the tank using the level

sensor. As pipe work is complete a test could be carried out to see that

there are no leaks present and test the force of the water hitting the

turbine is sufficient enough to rotate it.








Program the analog module to read the level in the tank using the level

sensor. As pipe work is complete a test could be carried out to see that

there are no leaks present and that the water dropping from the upper tank

via the solenoid valve can rotate the turbine.


I had some difficulty trying to figure out how to use the analog module to

read the depth of the water in the upper tank. The first test of letting water

through the system didn’t show up any leaks but the force of the water

falling down the pipe was not able to turn the turbine. With a more in

depth look at the solenoid valve it was realised that it was designed for a

pressurised system and therefore was not going to work for this project.


Research more on how to connect the analog module and come up with

an alternative way to increase the force of the water hitting the turbine to

get it to rotate.








Research more on how to connect the analog module and get some advice of the supervisor. Also must come up with an alternative way to increase the force of the water hitting the turbine to get it to rotate.


First of all it was decided to increase the penstock from half inch to ¾ inch. Then with help from the mechanical workshop a nozzle was machined to fit the ¾ inch copper pipe. This provided an increase in velocity of the water hitting the turbine. However the water was now being thrown out on the floor, therefore a small shield was put in place over the turbine and this worked well. The set up ladder logic for the AD module was installed and the PLC was reading the level sensor on channel two of the AD module.


Start tidying the project up and piece everything together. The supervisor agreed to seek permission for a computer to be delivered to the work shop to allow SCADA to be installed on to the project. Therefore the control panel had to be fixed close the computer to allow the leads to reach. Communication could not be

set up with SCADA.








Start tidying the project up and piece everything together. The supervisor agreed to seek permission for a computer to be delivered to the work shop to allow SCADA to be installed on to the project. Therefore the control panel had to be fixed close the computer to allow the leads to reach. Communication could not be set up with SCADA.


The panel was fixed in place in the workshop beside the project computer. All the loose ends were tidied up and SCADA was successfully installed.


Concentrate writing the report to compliment the build and add anything extra learned in the SCADA module as the year wears on.


FYP Report up to date COMPLETE

Documents

Transcript of FYP Report up to date COMPLETE