This document provides an overview of the author's 12-week industrial training at Ceylon Electricity Board (CEB) from December 2016 to March 2017. It includes: 1) An introduction to CEB, including its vision, mission, organizational structure, present performance, strengths, and weaknesses. 2) A description of the author's technical training experiences in CEB's Generation, Transmission, Distribution, Planning, and System Control divisions. Specific experiences at Lakvijaya Power Plant and Kotmale Power Station are discussed. 3) Details on the management training experiences in safety management and worker management. 4) A concluding chapter that will summarize the overall training experience and lessons learned.

1. i
PREFACE
As an undergraduate from Electrical and Information engineering department of University
of Ruhuna, I was assigned to 12 weeks industrial training program which was conducted
by collaboration of National Apprentice and Industrial Training Authority (NAITA) and
Engineering Education Centre of faculty of engineering. My industrial training
establishment was Ceylon Electricity Board. This report is a brief presentation of
knowledge and experience I have obtained during my three month training period from 19th
of December 2016 to 10th
of March 2017.
This report consists of four main chapters. The first chapter of this report give a brief
introduction to Ceylon Electricity Board, including history, vision and mission, present
performance and organizational structure of CEB.
Second chapter describes the technical training experience that I got from CEB. The chapter
further subdivided into Generation, Transmission, Distribution, Transmission and
generation planning and System Control Centre of CEB. Technical and theoretical
information are described under each sub divisions.
Third chapter gives the experience on management side, the administrative and office
practices and safety procedures.
Fourth chapter summarizes the training experience and it has conclusion of the training
program from Ceylon Electricity Board adopted by the EEC and NAITA.
Anujan K.
Department of Electrical and Information Engineering
Faculty of Engineering
University of Ruhuna

2. ii
ACKNOWLEDGEMENT
First of all I would like to pay my gratitude to those who helped, encouraged and guided
me to successfully completing my second industrial training of 12 weeks at Ceylon
Electricity Board. Also I must thank to our Training Coordinator Dr. J.M.R.S. Appuhamy,
Staff of Engineering Education Centre of Faculty of Engineering, University of Ruhuna
and staff of NAITA for giving me an opportunity to have a good training experience.
I would like to thank to Eng. Mrs. K.A.C.K. Premarathne, the training coordinator of
Ceylon Electricity Board, DGMs, Chief Engineers, Engineers, Technical officers and all
other staff who spent their valuable time for me at Ceylon Electricity Board.
Anujan K.
Department of Electrical and Information Engineering
Faculty of Engineering
University of Ruhuna

3. iii
Contents
PREFACE.............................................................................................................................i
ACKNOWLEDGEMENT...................................................................................................ii
1. Introduction about CEB...............................................................................................1
1.1 Introduction................................................................................................................1
1.2 Vision.........................................................................................................................1
1.3 Mission.......................................................................................................................1
1.4 Organizational structure.............................................................................................2
1.5 Present Performance ..................................................................................................3
1.6 Strengths and Weaknesses .........................................................................................3
1.7 Improvement Suggestion ...........................................................................................4
2. Training Experiences – Technical ...............................................................................5
2.1 Generation..................................................................................................................6
2.1.1 Power Generations in Sri Lanka .........................................................................6
2.1.2 Lakvijaya Power Plant ........................................................................................7
2.1.3 Kotmale Power Station .....................................................................................13
2.2 Transmission............................................................................................................17
2.2.1 Introduction.......................................................................................................17
2.2.2 Components of Grid Substation........................................................................18
2.2.3 Protection and Testing ......................................................................................23
2.3 Distribution ..............................................................................................................26
2.3.1 Introduction.......................................................................................................26
2.3.2 Project and Heavy Maintenance .......................................................................26
2.3.3 Pole Construction..............................................................................................30
2.3.4 Consumer Supply and Metering .......................................................................31

4. iv
2.4 Transmission and Generation Planning ...................................................................35
2.4.1 Generation Planning..........................................................................................36
2.4.2 Transmission Planning......................................................................................37
2.5 System Control Centre.............................................................................................38
2.5.1 Frequency Control ............................................................................................40
2.5.2 Voltage Control.................................................................................................40
3. Training Experience – Management..........................................................................41
3.1 Safety Management .................................................................................................41
3.2 Workers Management..............................................................................................42
4. Summary and Conclusion..........................................................................................43
4.1 Summary..................................................................................................................43
4.2 Conclusion ...............................................................................................................44
References..........................................................................................................................45
List of Corrections .............................................................................................................46

5. v
Table of Figures
Figure 1-1 CEB Logo...........................................................................................................1
Figure 1-2 Organization Structure .......................................................................................2
Figure 2-1Artistic view of Lakvijaya...................................................................................7
Figure 2-2 Tangential firing.................................................................................................8
Figure 2-3 Flue gas System..................................................................................................9
Figure 2-4 Steam Cycle .....................................................................................................10
Figure 2-5 Rankin Cycle....................................................................................................10
Figure 2-6 Turbine area .....................................................................................................11
Figure 2-7 Electrical System of Lakvijaya ........................................................................12
Figure 2-8 Mahaweli Complex..........................................................................................13
Figure 2-9 Kotmale Reservoir and Dam............................................................................14
Figure 2-10 Generator of Kotmale PS ...............................................................................15
Figure 2-11 Excitation system ...........................................................................................16
Figure 2-12 Transmission network of Sri Lanka ...............................................................17
Figure 2-13 Grid Substation...............................................................................................18
Figure 2-14 Surge arrester .................................................................................................18
Figure 2-15 Lighting Arrester............................................................................................19
Figure 2-16 Isolator............................................................................................................19
Figure 2-17 Oil Circuit Breaker.........................................................................................20
Figure 2-18 Current Transformers.....................................................................................20
Figure 2-19 Capacitor Voltage Transformer......................................................................21
Figure 2-20 Bar Bars..........................................................................................................22
Figure 2-21 Power Transformers.......................................................................................22
Figure 2-22 Angle of a Tower ...........................................................................................26
Figure 2-23 Tower components.........................................................................................27
Figure 2-24 Sticks used in hotline maintenance ................................................................29
Figure 2-25 Tools used in hotline maintenance.................................................................29
Figure 2-26 Single phase Direct Connected Meter............................................................33
Figure 2-27 Three phase Indirect Connected Meter ..........................................................33
Figure 2-28 Meter Tester ...................................................................................................34
Figure 2-29 Practical arrangement of meter tester.............................................................35
Figure 2-30 Flow Chart of LTTDP....................................................................................38

6. vi
Tables
Table 2-1 Training Schedule................................................................................................5
Table 2-2 Hydro Power Plants in Sri Lanka ........................................................................6
Table 2-3 Thermal Power Plants in Sri Lanka.....................................................................7
Table 2-4 Technical Data of Generator .............................................................................11
Table 2-5 Technical Data of Transformers........................................................................13
Table 2-6 Protections .........................................................................................................24
Table 2-7 Tower types .......................................................................................................27
Table 2-8 MV poles ...........................................................................................................30

7. vii
Abbreviation
APH – Air Pre Heater
AVR – Auto Voltage Regulator
BDV – Break Down Voltage
CEB – Ceylon Electricity Board
DGA – Dissolved Gas Analysis
ESP – Electro Static Precipitator
FD – Forced Draft
FGD – Flue Gas Desulfurization
GSS – Grid Sub Station
HP – High Pressure
HV – High Voltage
ID – Induced Draft
IP – Intermediate Pressure
IPP – Independent Power Producers
LP – Low Pressure
LTGEP – Long Term Generation Expansion Plan
LTTDP – Long Term Transmission Development Plan
LV – Low Voltage
MIV – Main Inlet Valve
MV – Medium Voltage
NCRE – Non Conventional Renewable Energy

8. viii
ONAF – Oil Natural Air Forced
ONAN – Oil Natural Air Natural
PA – Primary Air
PI – Polarization Index
PS – Power Station
SFRA – Sweep Frequency Response Analysis

9. 1
CHAPTER 01
1. Introduction about CEB
1.1 Introduction
Ceylon Electricity Board (CEB) is established in Sri Lanka on the 1st
November 1969. It
is empowered to Generation, Transmission and the Distribution of the Electrical Energy to
different categories of consumers in Sri Lanka and to collect the revenue. Currently the aim
of the Ceylon Electricity Board is to provide a high quality and affordable service to its
customers. It is the duty of the CEB to make the optimal use of the resources through the
application of pragmatic and time tested managerial methods. Currently CEB serves
approximately 98% of the public with wider network across the country.
Figure 1-1 CEB Logo
1.2 Vision
Enrich life through power
1.3 Mission
To develop and maintain an efficient, coordinated and economical system of electricity
supply to the whole of Sri Lanka, while adhering to our core values
 Quality
 Service to the nation
 Efficiency and effectiveness

10. 2
 Commitment
 Safety
 Professionalism
 Sustainability
1.4 Organizational structure
Figure 1-2 Organization Structure
This is the structure of main divisions. In every divisions they have separate structure for
their divisions.

11. 3
1.5 Present Performance
CEB is divided into main three parts Generation, Transmission and Distribution. Most of
the generation plants in Sri Lanka is owned by the CEB and this generation is done mainly
by Thermal and Hydro power plants and CEB is getting NCRE sources such as Solar and
Wind Power. Also currently, the license for generation and distribution are issued for IPPs.
But the transmission is done only by CEB. [1]
In order to distribute the electricity for all the island and almost equal the revenue CEB has
divided the country into four divisions. [1]
 Division 1: Colombo City, North Western, North Central and Northern provinces
 Division 2: Western-North, Central and Eastern provinces
 Division 3: Western south (some parts), Uva and Sabaragamuwa province
 Division 4: Western south (other parts) and Southern province
1.6 Strengths and Weaknesses
CEB is a government organization. So, that is a main strength of the CEB. Another major
strength is CEB holds monopoly in the power sector so they don’t have any competitor in
the market. CEB also have well experienced, qualified professional staff with expert
engineers and specialist technicians.
In market side consumers are increasing day by day and CEB has a monopoly market. Also
workers are eager to join with the CEB because of the reputation of the CEB.
In CEB the efficiency is went down and some works are ineffective due to inability of the
workers. CEB is lacking of new ideas and new inventions. This is the major weakness in
the CEB.
Hydropower generation is becoming limiting in Sri Lanka, Hydropower is a major thing in
power generation in Sri Lanka because there are no Thermal power station which is capable
to control the system frequency so CEB should have to think about that.
CEB not only focuses on making profits they mainly focused on providing quality and
reliable supply to the country. CEB works under government policies. To maintain reliable
and quality supply CEB making losses every day in Millions.

12. 4
1.7 Improvement Suggestion
CEB is a major part of country’s economy, development and human life. Without electricity
it will be difficult. CEB provides high quality reliable power supply for desirable tariff
structure. But CEBs loss is high compared to their revenue so they have to work on
techniques to reduce their losses. CEB have to work on new researches on renewable
energy and new methods to improve quality and reliability of the supply. I think to do that
they have to improve their research and development facilities. CEB works on programs to
aware people to reduce the peak demand of the country.

13. 5
CHAPTER 02
2. Training Experiences – Technical
My second industrial training completed at Ceylon Electricity Board from 19th
of December
2016 to 10th
of March 2017. I assigned to Generation, Transmission and Distribution
divisions, Planning division and System Control of CEB. Therefore I worked different
places to complete my training. In this chapter I included theoretical information and also
my experiences which I got from the training.
My industrial training schedule of 12 weeks under different divisions at Ceylon Electricity
Board is described below.
Table 2-1 Training Schedule
Division Period
From To
Projects & Heavy maintenance – DD3 19.12.2016 01.01.2017
Transmission Generation Planning 02.01.2017 08.01.2017
System Control Centre 09.01.2017 15.01.2017
Transmission (Operation & Maintenance)
Anuradhapura Region
16.01.2017 29.01.2017
Lakvijaya Power Station 30.01.2017 12.02.2017
Kotmale Power Station 13.02.2017 26.02.2017
Uva Province 27.02.2017 10.03.2017
Generation, Transmission and Distribution of electricity is the main works carried out by
CEB. Also CEB have planning and system control divisions to give uninterrupted power
supply to the users.

14. 6
2.1 Generation
2.1.1 Power Generations in Sri Lanka
In Sri Lanka Hydro and Thermal power generation are the major two methods used to fulfill
the power requirement of the country. Other than this two generation there are wind power,
solar power and mini hydro plants generate and give the power to the system. [2]
When consider about the hydro generation, plants are divided into three main complexes,
Mahawali complex, Laxapana complex and Samanala wewa. Other than these complexes
there are some small power plants are generate electricity. [1]
Details of some hydro power stations and their plant generations are given in table 2.2. [2]
Table 2-2 Hydro Power Plants in Sri Lanka
Hydro Power Plant No of Units Total Capacity (MW)
Victoria 3 210
Kotmale 3 201
Upper Kotmale 2 150
Randenigala 2 122
Samanala wewa 2 120
New Laxapana 2 115.2
Polpitiya 2 75
Kukule 2 74
Canyon 2 60
Old Laxapana 5 53.5
Wimalasurendra 2 50
Rantambe 2 50
Ukuwela 2 40
Bowatenna 1 40
When consider about the thermal generation, mainly coal and diesel power plants
contribute to the national demand.
Details about some thermal power stations and their plant generations are given below.

15. 7
Table 2-3 Thermal Power Plants in Sri Lanka
Thermal Power Plant No of Units Total Capacity (MW)
KPS Gas Turbine 5 100
KPS Gas Turbine 7 1 115
KCCP 1 165
Sapugaskanda Diesel A 4 80
Sapugaskanda Diesel B 8 80
Lakvijaya Coal 3 900
Uthuru Janani 3 26.7
2.1.2 Lakvijaya Power Plant
I went Lakvijaya power plant for gain the knowledge about thermal power plant generation
section.
Introduction
Lakvijaya is the first coal fired power plant in Sri Lanka. This coal fired plant has three unit
with total capacity of 900 MW. Main contribution to the base demand of the island is given
by Lakvijaya plant. Here I describe about the operation of coal power plant with the
knowledge of coal handling and Steam cycle, maintenance, instrumentation and control of
the plant, turbines, generators and also some sub systems in the Lakvijaya power plant such
as water treatment plant, chlorine plant and hydrogen plant.
Figure 2-1Artistic view of Lakvijaya

16. 8
Operation
When we consider about the operation of the Lakvijaya plant, coal is used for fuel that
means coal is used to fire and produce the steam for the rotation of turbine.
Coal come to the Jetty from the ships. There are five barges each have 2000 ton coal
capacity carry the coal from ship to jetty. From the jetty coal feed to the coal yard through
the belt system. After that coal is feed to the bunkers. There are 9 belts work to carry the
goal between jetty and bunkers.
Each unit have five bunkers as a temporary storage. For a unit per day coal consumption is
around 2500 tons. Each bunker has a coal mills. From the bunkers coal is feed to the mills
by the feeders for the pulverizing. Feeders have the facility of control the coal amount feed
to the mills. After that pulverized coal is feed to furnace.
To feed the coal to the furnace, hot air is used as a medium. The hot air get from the
centrifugal type Primary Air fans (PA fan). PA fan get the air from the environment and
the air go to air pre heater (APH) which is a heat exchanger to get the heat. After that the
hot air go to mixed with pulverized coal and feed to the furnace.
When consider about the boiler, there are five coal guns and three diesel guns in each
corner. Diesel guns are used to fire the diesel when startup the plant.
Coal is feed in four corners of the boiler and hot air also feed to burn the coal powder. The
air get by the Forced Draft fans (FD fan) and it goes to APH to get heat and feed to furnace.
Here the coal fired as “Tangential firing” to maintain the flame in the middle of the furnace.
Figure 2-2 Tangential firing

17. 9
In order to maintain the flame inside the furnace, the pressure of the boiler is maintain as
(-50 Pa). To maintain this negative pressure and suck the flue gas, here Induced Draft fans
(ID fan) are used.
Bottom ash of the burned coal is flow under furnace to the water seal collector and the fly
ash goes with the flue gas. Then flue gas goes to ESP to remove the particles of the fly ash
by the ionization. After that flue gas goes to the FGD through ID fan. In FGD, the sulfur
ions removed by the sea water and feed to the sea. After the FGD the flue gas removed by
the stack.
The coal path from the mill to stack is illustrated as below.
Figure 2-3 Flue gas System
Steam Cycle
The steam cycle is a close cycle system. “Rankin cycle” is used here for the steam.
Demineralized water get into condenser pump and then goes to heaters. After that the
saturated gas goes to the drums and then super-heated steam feed to HP turbine. From the
HP turbine, steam is reheated and feed to IP turbine and then LP turbine. After the LP
turbine steam goes to condenser. Then condensed water pump to the heaters by the
condenser pump.

18. 10
Steam path and the Rankin cycle are given in following diagrams.
Figure 2-4 Steam Cycle
Figure 2-5 Rankin Cycle
1 – Condenser pump 2 – Low pressure heater 3 – Main pump
4 – High pressure heater 5 – Drum 6 – Super heater
7 – HP turbine 8 – Re heater 9 – IP turbine
10 – LP turbine 11 – Condenser

19. 11
Turbines and Generators
Three turbines such as High pressure, Intermediate pressure and Low pressure turbines are
mounted on a same shaft. Rotational speed of the shaft is 3000 rpm. Turbine consist of dual
casings and dual steam exhaust.
When we consider about the generator, here the generator is two pole cylindrical rotor type
synchronous machine. Stator core and field winding are cooled by closed circuit hydrogen
cooling system. The stator windings, leads and terminals are cooled with de ionized water.
Table 2-4 Technical Data of Generator
Rated power 300 MW
Rated voltage 20 kV
Rated current 10190 A
Rated speed 3000 rpm
Rated frequency 50 Hz
Power factor 0.85
Excitation Potential source Static exciter
Figure 2-6 Turbine area

20. 12
Electrical System
The electrical system of Lakvijaya power plant contain following components
 Generators
 Main Transformers (MT)
 Unit Auxiliary Transformers (UAT)
 Startup Standby Transformers (SST)
 6kV/400V transformers
 Emergency diesel generator
 UPS and battery bank
 Power Distribution Centre (PDC)
 Motor Control Centre (MCC)
 DC supply system
Three generates the power with 20 kV and then it will be step up to 220 kV by MT. Other
than the MT there are 03 UATs and 02 SSTs are used to get the auxiliary power from the
20 kV and 220 kV.
Figure 2-7 Electrical System of Lakvijaya

21. 13
Table 2-5 Technical Data of Transformers
MT UAT SST
Rated power (MVA) 360 50/31.5-31.6 50/31.5-31.5
Rated voltage (kV) 242±8x1,25%/20 20±2x2.5%/6.3-
6.3
220/6.3-6.3
Cooling ONAN (30%)
ONAF (60%)
ODAF (100%)
ONAN (67%)
ONAF (100%)
ONAN (67%)
ONAF (100%)
Voltage group YN d1 Dy11-Yn11 YN yn0-yn0
Other than these, there are some sub systems available in Lakvijaya power plant. Water
treatment plant such as pretreatment and make up water section, Chlorine plant, Hydrogen
plant, Polishing and waste water systems are available in Lakvijaya.
2.1.3 Kotmale Power Station
For the hydro power generation section I assigned to the Makaweli complex. In Mahaweli
complex there are 8 power stations generate the electricity. Kotmale, Victoria, Ukuwela,
Bowatenna, Randenigala, Rantambe, Nillambe and Upper Kotmale are the power stations
which are related to the Mahaweli complex.
Figure 2-8 Mahaweli Complex

22. 14
In the Mahaweli complex I went to Kotmale power station to gain the knowledge about
hydro power generation.
Introduction
Kotmale power station is one of the major hydro power plant in Sri Lanka. This is the first
underground power station in Sri Lanka. Kotmale power station has 3 units each have 67
MW. Kotmale power station is used to control the frequency. Kotmale power station is
commissioned in year 1985. To generate the electricity water is taken from Kotmale Oya
which is a main affluent of Mahaweli Ganga.
Reservoir
The reservoir has the catchment area of 544 km2
and the top water level of 703 m. Station
can operated until the level of 665 m. Total storage of the reservoir is 174 MCM. Here
Rock fill with concrete membrane type dam is constructed to store the water.
Figure 2-9 Kotmale Reservoir and Dam
Water flow
From the reservoir water carried through tunnels. The high pressure tunnel is made out of
steel to withstand the high pressure of the water inside the tunnel. The low pressure tunnel
is about 7 km long and the water pressure is lower than high pressure tunnel.

23. 15
From the tunnels water goes to MIV through penstock which has the length of 120 m. The
MIV is a rotary type valve. The water enters to the turbine from MIV to the spiral casing
and to the wicket gates. There are 24 wicket gates are used to control the water flow to the
turbine.
After that the water flows through conical shape draft tube. After that the water enters to
the downstream surge chamber and then flows to outside through the tailrace.
Turbine and Generator
When we consider about the turbine, here Francis type vertical turbine which has speed of
375 rpm is used. Rating output is 67 MW with the 201.5 m design water head. Flow rate of
the water is 37.2 m3
/s.
Here conventional type vertical Generators are used in Kotmale. There are three bearings
such as upper guide bearing, trust bearing and lower guide bearing are in this generator.
Generator is rated for 90 MVA with 0.85 power factor. 13.8 kV and 375 rpm are the rated
voltage and speed of the generator. It has 16 poles and the output is 67 MW. 200v pilot
excitation is used to excite the generator. Closed air/water cooling system is used in this
generator.
Figure 2-10 Generator of Kotmale PS

24. 16
Excitation System
In Kotmale power station generator units have the brushless excitation system to excite the
generator. Initially 200 V DC supply is given to generator excitation through AVR from
auxiliary supply. When generator reaches about 275 rpm the 220 DC supply is directly
taken from the generator output. [4]
The graphical description of the excitation system is illustrate below.
Figure 2-11 Excitation system
Switchyard
Here the generated voltage of 13.8 kV step up into 220 kV by three transformers. The
transformer capacity is 90 MVA. For each unit there are three single phase transformers
are externally connected in delta to create a three phase transformer.
The 220 kV lines connected to New Anuradhapura (02 lines), Biyagama (02 lines), Victoria
(02 lines) and Upper Kotmale (02 lines). [4]

25. 17
Nillambe PS
This is a mini hydro power plant in Mahaweli complex under the Kotmale PS. The total
generation is 3.2 MW. Francis type horizontal axis turbines are used in Nillambe. There are
two units each have 1.6 MW capacity used to generate the power. The design water head
is 110 m.
2.2 Transmission
2.2.1 Introduction
From the power station to the grid substation is considered as transmission. In Sri Lanka
220 kV and 132 kV voltages are used to transmit the electricity. The transmitted voltages
are step down to 33 kV for distribution at the grid substation. For the transmission division
I assigned to the Anuradhapura region. There I went to New Anuradhapura, Vavuniya,
Chunnakam, Killinochi and Puttalam grid substations.
Figure 2-12 Transmission network of Sri Lanka

26. 18
2.2.2 Components of Grid Substation
Figure 2-13 Grid Substation
Surge Arrester
Surge arresters are used to protect the equipment and insulations from lighting surge
(external) and switching surges (internal). The surge arresters are diverting the surge
current to the earth in a case of surge.
Figure 2-14 Surge arrester

27. 19
Lighting Arrester
Lighting arrester is used to protect the insulation and conductors from the damaging effects
of lighting. The typical lighting arrester has a high voltage terminal and a ground terminal.
Figure 2-15 Lighting Arrester
Isolators
Isolator is a switch operated manually, which separate the circuit from the power main and
discharges the trapped charges in the circuit. It is disconnect under no load condition for
safety maintenance. An isolator visually certifies that it is been disconnected from the line.
Figure 2-16 Isolator

28. 20
Circuit Breakers
A circuit breaker is an automatically operated electrical switch designed to protect an
electrical circuit from damage caused by excess current, typically resulting from an
overload or short circuit. Its basic function is to interrupt current flow after a fault is
detected. Circuit breakers use oil and SF6 as insulation.
Figure 2-17 Oil Circuit Breaker
Current Transformers
A current transformer (CT) is a type of transformer that is used to measure AC Current. It
produces an alternating current (AC) in its secondary which is proportional to the AC
current in its primary. It is transform currents or voltages from a usually high value to a
value easy to handle for relays and instruments.
Figure 2-18 Current Transformers

29. 21
Capacitor Voltage Transformers
A capacitor voltage transformer is a transformer used in power systems to step down extra
high voltage signals and provide a low voltage signal, for metering or operating a protective
relay.
Figure 2-19 Capacitor Voltage Transformer
Voltage Transformers
Voltage transformers used in protection and instrumentation purposes by act as a measuring
instrument for voltage. One end of the primary winding of VT is connected to the power
line and the other end is connected to the ground. The secondary winding is placed such
that, the voltage is lower than the primary winding.
Bus Bars
Bus bar is a metallic strip or bar used for local high current power distribution. They are
also used to connect high voltage equipment at electrical switchyards, and low voltage
equipment in battery banks. They are generally uninsulated, and have sufficient stiffness to
be supported in air by insulated pillars.
Power Transformers
In a GSS transformer is the main equipment. The power transformers are used to step down
the voltage from 220 kV or 132 kV to 33 kV. Three phase star-delta connected transformers
are used to this function.

30. 22
Figure 2-20 Bus Bars
Figure 2-21 Power Transformers

31. 23
2.2.3 Protection and Testing
When consider about the transformers, there are some methods to test the transformers.
These testing done in different time period and various purposes. Some of the transformer
testing are described below.
Break Down Voltage Test
Break down voltage test. Also called as Dielectric strength value. The BDV test mainly
done for insulation oils in transformers. During a transformer operation, the insulation oils
become dirty. This results loosing function of the oil in a transformer as insulation and
cooling.
Therefore the BDV test done for monitor and check the quality of the oil. When a low value
get in a BDV test, then the oil has to be replaced or purified [3]
Dissolved Gas Analysis Test
Dissolved gas analysis of transformer oil. When a transformer goes under abnormal thermal
and electrical stresses, certain gas produced due to decomposition. If the fault is major,
decomposed gases are more and they collected in Buchholz relay. But abnormal condition
is small and gasses are low, then the gas will dissolve in oil.
So, only look at the Buchholz is not enough to identify the dissolved gas. Therefore DGA
test is done to transformers.
In DGA test gasses are extracted from oil and analyze the quantity of gasses in a specific
amount of oil. By observing the percentages we can predict the internal condition of
transformers. [3]
Polarization Index Test
Polarization index test. This test conducted on HV machine to determine service condition
of the insulation. In HV machines windings are likely to be affected by moisture and
contamination. Therefore the PI test done for identified the condition of the windings and
insulation. [3]
Sweep Frequency Response Analysis Test
Sweep frequency response analysis. The SFRA is done to condition monitoring of the
physical condition of transformer windings. [3]

32. 24
Transformer windings may be subjected to mechanical stresses. These may cause
displacement of the transformer windings from their position. Therefore SFRA test is done
for transformers. SFRA detects efficiently displacement of transformer core, deformation
and displacement of windings, collapse of partial windings, short circuited turns and open
winding conditions.
There are some protections in a grid substation to protect the devices. Some of the
protections and their ANSI codes are given below.
Table 2-6 Protections
ANSI code Protections
87L Current difference for lines/cables
87T Current difference for lines/cables with transformers
87N Low impedance restricted ground-fault protection for transformers
85 Phase-selective inter trip, remote trip
86 Lockout function
21/21N Distance protection
FL Fault locator
68/68T Power swing detection
85/21 Teleportation for distance protection
21W1 Weak in feed protection
50N/51N/67N Directional/earth fault protection
85/67N Teleportation for earth fault protection
50/50N/51/51N Overcurrent protection
81 O/U Over/under frequency protection
50BF Breaker failure protection
When we consider about the protection side, there are some relays used to identify the
faults. Distance and difference relays are demonstrated below.
Distance Protection
Distance relay working depending upon the distance of a fault in the line. It detects both
voltage and current. A fault on a circuit generally create a sag in the voltage level. If the

33. 25
ratio of voltage to current measured at the relay terminals is within the predetermined level,
then the circuit breaker will operate. The distance relay operate as impedance between the
point of fault and the point where relay is installed is measured. If the relay setting is
determined to be below the apparent impedance it is determined that the fault is within the
zone of protection. Zones are set based in percentages of the line impedance.
Zone 1 – 80% of the impedance of the line
Zone 2 – 120% of the impedance of the line
This distance protection is useful for reasonable length lines.
Differential Protection
Differential relay is very commonly used relay for protecting transformers and generators
from localized faults. Differential relays are very sensitive to the faults occurred within
the zone of protection but they are least sensitive to the faults that occur outside
the protected zone. Most of the relays operate when any quantity exceeds beyond
a predetermined value for example over current relay operates when current through
it exceeds predetermined value. But the principle of differential relay is somewhat
different. It operates depending upon the difference between two or more similar electrical
quantities.
There are mainly two types of differential relay depending upon the principle of operation.
 Current Balance Differential Relay
 Voltage Balance Differential Relay
Buchholz Relay
Buchholz relay in transformer is an oil container housed that connecting pipe from
main tank to conservator tank. It has mainly two elements. The upper element consists of
a float. The float is attached to a hinge in such a way that it can move up and down
depending upon the oil level in the Buchholz relay Container . One mercury switch
is fixed on the float. The alignment of mercury switch hence depends upon the position
of the float. The lower element consists of a baffle plate and mercury switch. This plate
is fitted on a hinge just in front of the inlet of Buchholz relay in transformer in such a
way that when oil enters in the relay from that inlet in high pressure the alignment of
the baffle plate along with the mercury switch attached to it, will change.

34. 26
2.3 Distribution
2.3.1 Introduction
When consider about the distribution system of Sri Lanka mainly the system divided into
four division, in order to equal the supply and maintenance work. Among those four
division I assigned to the Distribution Division 3.
DD3 contains Uva, Sabaragamuwa and some Western province south parts.
In Sri Lanka the distribution voltages are 33 kV, 11 kV and 400 V. Mostly 11 kV voltages
used by LECO for their distribution. 400 V used to normal consumers.
In this part I describe about Project and heavy maintenance, Construction of new lines,
Consumer supply and metering and maintenances.
2.3.2 Project and Heavy Maintenance
Tower Types
33 kV and 11 kV voltages are considered as medium voltage. According to the carrying
conductors lines are divided into single circuit lines and double circuit lines. Therefore the
towers which used in these lines named as single circuit towers and double circuit towers.
Also towers are categorized into further according to their positions as bellows
Terminal Towers: These type towers are positioned in a starting or ending of a line. These
towers have the ability of manage tension in one side.
Line Towers: These type of towers are used in the middle of the line. They are not have
an angle. Mostly they have suspension type insulators. Which means mostly they used to
hold the cable in between the lines.
Medium Angle: These type towers used for 0 – 300
angle turning.
Heavy Angle: these type towers used for 300
– 600
angle turning.
Figure 2-22 Angle of a Tower

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Therefore according to above categories, towers are named as follows.
Table 2-7 Tower types
Tower type Mast type
Single circuit Double circuit Single circuit Double Circuit
Terminal TST TDT MST MDT
Medium angle TSM TDM MSM MDM
Heavy angle TSH TDH MSH MDH
Line TSL TDL MSL MDL
A tower consists of the following components
Peak of tower Cross arm Boom of tower
Cage Tower body Leg of tower
Anchor bolt and base plate assembly
A typical tower design is given below
Figure 2-23 Tower components

36. 28
Hot Line Maintenance
Hot lines maintenance means, the maintenance of electrical equipment or transmission line
carried out while the equipment or line is energized. That means do the maintenance work
while giving the supply in the line. This is often operating at high voltage. This is also
called as live line maintenance.
In Sri Lanka generally two methods are used for the hot line maintenance
 Hot stick method
 Bare hand method
Hot stick method:
Hot sticks are used in live line work by having the worker remains at a specified distance
from the live parts and carry out the work by means of an insulating stick.
Bare hand method:
The bare hand approach has a live line worker performing the work in direct electric contact
with live parts.
Here I describe the steps that followed to replace the suspension insulator.
 Fixing hand line – this one fixed to carry the tools between the top of the tower and
ground.
 Fixing tower saddle – generally saddle is fixing one feet below the conductor.
 Fixing wire tone with rope blocks
 Fixing link sticks with rope blocks – these sticks are used to hold the conductor
 Disconnecting ball joint – by doing this the conductor will separate from insulator.
 Moving conductor away from the tower – by using wire tone and link stick the
conductor is moving away from the tower.
 Removing insulator set
 Sending the old insulator to the ground and new insulator set to the tower using
hand line.
 Fixing new insulator set to the cross arm.
 Moving conductor towards insulators.
 Engaging ball joint
 Removing tools.

37. 29
In my training period I observed the replacement of suspension insulator by hot stick
method.
Figure 2-24 Sticks used in hotline maintenance
Figure 2-25 Tools used in hotline maintenance

38. 30
2.3.3 Pole Construction
When constructing a new line or extending the line there are some steps have to be
followed.
First, commercial engineer give the sketch and details about the new line. This includes the
existing lines, consumer details, materials and all the details about construct line. After that
the pegging sketch will be prepare and do the begging. Then the cost estimation will be
prepare according to the “Catalogue and price list of materials” which prepared by CEB
every year. After preparing the estimate, the full details of the line with position of poles,
types of poles, amount of poles, details about equipment and worker details are included
and handover to the area engineer. Then the area engineer start the work of new
construction of the line.
Medium Voltage Lines
Medium voltages have 33 kV and 11 kV voltages with neutral solidly earthed at primary
substation and grid substation.
When construct the MV overhead lines we have to consider the following things.
 Line should be along roads and be straight as far as possible.
 Place has the access for construction and future maintenance work.
 Have to consider environmental and aesthetic considerations.
 Consider about the availability and suitability of land to erect poles.
 Avoid heavy angles and deviation of lines.
 Avoid crossing building sites, valuable vegetation place and play grounds.
Mostly there are three type of poles used in MV overhead lines.
Table 2-8 MV poles
Height Place where install Circuit type
10 m In cross country Single circuit
11 m Along the roads Single circuit
13 m Along the roads Double circuit

39. 31
MV overhead lines strung horizontally for single circuit and vertically for double circuits.
Also double circuit with different voltages (33 & 11 kV) strung horizontal with higher
voltage at the top.
According to the positions of the poles, they are categorized as follows.
Terminal pole: line terminated with MV tension insulators on one side of the pole
Shackle pole: line terminated with MV insulators on both side of the same pole.
Intermediate pole: line is continuous and is supported in MV pin insulators as necessary.
Self-supported pole: used in urban and densely populated area. Strays and struts cannot
be erected.
The maximum sag of the overhead line is given as follows.
max sag =
Wl2
8T
Where,
W – Weight per unit length of conductor
l – Length of design span
T – Tension at maximum temperature
Low Voltage Lines
Nominal voltage of LV is 400/230 V with neutral earth at distribution substation.The
construction procedure almost same as MV lines. In LV lines earth system is TT system.
That means all exposed conductive parts of an installation are connected to an earth
electrode. Overhead earth wire run on the poles and metal parts of poles should connected
to earth wire. This should be connected through earth electrodes at each shackle point and
the terminal points. Overhead earth wire connected to low voltage neutral and earthed
through on effective earth electrode at the substation.
2.3.4 Consumer Supply and Metering
When consider a distribution unit, they are having the following key factors.
 Improve system reliability
 Protecting public and employee safety

40. 32
 System maintenance
 Service connections
 Metering, billing and revenue collection
 System planning and energy management
In Sri Lanka there are three types of services or connections given by the distribution units
for the consumers.
 Retail supply – below 42 kVA
 30 A single phase (7 kVA)
 30 A three phase (21 kVA)
 60 A three phase (42 kVA)
 Bulk supply – 42 kVA to 1 MVA
 HT metering system – above 1 MVA
If a consumer want to get a new connection first the consumer have to get application and
give the details about what are the power consuming devices, what type of connection need
for their places and details about neighbor’s consuming and other details. According to the
details, the supply type will be decided and then account will be opened. After that the path
of new connection is measured and get the equipment and prepare the estimate. Then some
part of estimated cost will be get from the consumer as a fixed cost and connection is
approved and supply is given.
Metering
There are two type of meters used to measure the power consumption of a consumer. They
are,
 Direct connected meters
 Indirect connected meters
Direct meters are directly connected to the incoming lines while indirect meters are get
current reading from CT.
Single phase and three phase supply retail supplies are use the direct meters. Bulk supply
and HT metering are use indirect meters.

41. 33
Figure 2-26 Single phase Direct Connected Meter
Figure 2-27 Three phase Indirect Connected Meter
Meter Testing
Due to bearings and permanent magnet places on the rotating plate, the revolution of the
rotating plate is deviated from its rated value. That will be harmful for consumer also
electricity board. Therefore meters should be check to observe the rotation speed is correct
or deviated.
Therefore meter tester will use to check the meter. There are many type of testers are used
to check the meters.

42. 34
Figure 2-28 Meter Tester
Here, the voltage terminals directly connected to outgoing side of the meter. Current is
measured by CT.
The rotation speed was calculated by the following methods
Manually start and stop pulses
Using a proximate switch start and stop the pulses
Using a proximate sensor identify the rotation speed.
After test the meter, if any deviation identified, we have to adjust the bearings and
permanent magnet position to correct the error.

43. 35
Figure 2-29 Practical arrangement of meter tester
2.4 Transmission and Generation Planning
CEB has to develop and maintain an efficient, coordinated and economical system of
electricity supply for whole Sri Lanka and generate sufficient electricity in order to satisfy
the demand. There is a long period of process when adding new systems or modify the
existing system when the demand is changing. Therefore we have to forecast the future and
make the plan according to the forecast.
The transmission and generation planning branch of CEB make this forecasting and
carryout the changes in generation and transmission in the existing system.

44. 36
2.4.1 Generation Planning
Here Long Term Generation Expansion Plan (LTGEP) is prepared by the generation
planning section.
This LTGEP is prepare for 20 years of future forecasting and it will be revise every two
years.
The LTGEP have information about existing generation system, generation planning
methodology and system demand forecast.
The demand forecast will consider about GDP, population, electricity price, previous year
demand and also past forecast. This is the economic demand forecast.
This generation plan consider the electricity consumption, capacity and demand and
generation of existing system.
Main objectives of the LTGEP are,
 Investigate the feasibility of new generating plans.
 Investigate the future operation of plants in order to determine the most economical
operating.
 Determine the economically optimum mix of generating plants to meet the forecast
demand.
The LTGEP analyze the following things
Existing and committed generating system. Here analyze consists of hydro and other
renewable energy and their capacity, thermal generation and their capacity of both CEB
and IPPs.
Electricity demand – here consider about past and forecast demand.
Conventional and non-conventional renewable generation options for future expansion.
Estimate hydro, thermal and also mini hydro, solar, wind, biomass energy production.
After the generation planning study get the results and implementation and financing of
generation projects.
Also LTGEP have the analysis about environmental implications such as greenhouse
gasses, country context, control of emissions, climate changes and etc…

45. 37
2.4.2 Transmission Planning
Here Long Term Transmission Development Plan (LTTDP) is prepared by the transmission
planning section.
This LTTDP is prepared for 10 years of future forecasting and it will be revise every two
years.
The LTTDP consist the information about present status of the transmission network,
transmission planning methodology and transmission development proposal for 10 years.
The report is prepared by considering the load forecast.
The main objectives of the LTTDP are
 Find the transmission developments required to ensure reliable and stable power
system
 Determine the investment for development
The transmission planning report basically consider about the following two keys
 National power and Energy demand forecast (NPEDF)
 Long Term Generation Expansion Plan (LTGEP)
Based on NPEDF and geographical distribution of load, the grid demand will be forecast.
For load forecast we have to consider about spot loads and distribution loads. Analysis
made on grid wise, by considering natural forecast (from past year forecast) and also add
major loads.
According to above details demand forecast will be design for a year as grid wise for night
peak and day peak cases. When we consider a year, the transmission network system design
for the following cases.
 Hydro power maximum day peak
 Thermal power maximum day peak
 Hydro power maximum night peak
 Thermal power maximum night peak
 Off peak

46. 38
By considering above all the five cases a transmission network for a particular year will be
forecasted. Also when forecasting consider the contingency analysis like (n-1) criteria.
According to all the forecasting the transmission network will design with the
modifications to satisfy the load demand of Sri Lanka.
Figure 2-30 Flow Chart of LTTDP
2.5 System Control Centre
Mainly there are three section under this SCC. They are System Operation (SO), Operation
planning (OP) and Operation Audit (OA). When consider about system operation, system
studies and system control sections under the SO and there are plant schedule and energy
management under OP section.
Main functions of the SCC are control the frequency, control the voltage and release lines
and machines for the maintenance.

47. 39
To obtain these functions first the SCC has to maintain the operation policy. Main policies
are system operation priority, water usage priority, spinning reserve, system frequency and
voltage and maximum generation unit.
System operation priority
 Safety of persons
 Protection of equipment
 Availability of supply
 Quality of supply
 Economics of system operation
Water usage priority
 Water service and drainage
 Environment
 Irrigation
 Power
Frequency - ±1% tolerance
Voltage 220 kV and 132 kV - ±10% tolerance
33 kV - ±2% tolerance
Spinning reserve – 5% of the total demand
Maximum generator unit – 30% of total demand
Above policies should be consider by system control engineers when control the network.
First the planning section going to plan the operation and generation for one year period.
But after that every one month period also this will be revised. Also for a week the operation
planning engineer will decide the generation plan. After the planning the water
management directory and merit order are given to system control engineers. According to
those they are going to operate the power plants for generation.
The ultimate aim of CEB is match the demand with the supply. Therefore the SCC has to
consider the policy and the planning documents, they are going to decide or operate the
generators and supply the electricity.

48. 40
2.5.1 Frequency Control
For match with the demand and supply we have to maintain 50 Hz frequency of the system.
The policy states that the tolerance is 1%. So system frequency is maintain between
49.5Hz-50.5Hz. When demand increases the frequency will reduce. Therefore we have to
increase the frequency. Also when demand decreases then frequency going to increase. So
we have to reduce the frequency.
To change the frequency CEB control some hydro power plants. But at the time only one
plant access the frequency control. By change the power station turbine or generator speed,
we can control the frequency.
Frequency control is done by following PS
Victoria, New Laxapana, Samanalawewa, Kotmale, Upper Kotmale, KPS
2.5.2 Voltage Control
The CEB maintain the voltages in a standard level. Tolerance for 132 kV and 220 kV is
10% and for 33 kV is 2% because it is a distribution voltage.
The terminal voltage will decrease with increment of the reactive power. Also the terminal
voltage will increase with the decrement of the reactive power.
In order to control the system voltage, the SCC following some methods.
Use the capacitor bank
Transformer tapping
Change the generator excitation
Add or remove the feeders

49. 41
CHAPTER 03
3. Training Experience – Management
3.1 Safety Management
Since CEB workers working with high voltage sources, safety is the most important
consideration of CEB. While doing the construction and maintenance works workers
should use the safety equipment in order to protect them. Otherwise, if the correct safety
procedures are not used, sometimes people may death. Therefore some safety tips used
during works.
Following are some safety wears for workers.
 Safety shoes
 Safety helmets
 Safety uniform
 Safety belt
 Ear protection
 Eye protection
 Respirators
Also when doing the maintenance works, the live lines should be removed from power and
should be earth both side of maintenance area.
When consider about the fire protection, Fire protection equipment are provided for most
of the sections in CEB for any emergency needs. Especially in a power plant fire safety is
a major thing because if a power plant is grabbed by a fire it will be a huge loss to the
national power supply system.
Following fire distinguishes methods are used in CEB.
Water – Red
Dry chemical powder – Blue
CO2 – Black
Form – Cream

50. 42
3.2 Workers Management
When consider the workers, CEB have enough workers for the construction and
maintenance work. Rather than that CEB hired some workers and sub-contractors for their
works.
There are different types of workers under Ceylon Electricity Board from the higher level
to minimum level workers. Every divisions have separate workers for their construction
and maintenance works. These workers also divided into levels according their knowledge,
experience and works. For the hot line maintenance, the amount of workers very less in Sri
Lanka. Only about hundred people works for the hotline maintenance in all divisions. But
for the normal construction works and maintenance works CEB have enough workers in
all divisions. Also CEB give some works like tower construction to sub-contractors.
Therefore CEB manages workers for their works without any lack of workers.

51. 43
CHAPTER 04
4. Summary and Conclusion
4.1 Summary
I assigned as a trainee at Ceylon Electricity Board for my second industrial training for 12
weeks period. During that 03months period I achieved lot of knowledge and experience
relating to the electrical generation, transmission and distribution, inner workings of an
Engineering firm, interactions with the officials and more. Also I could improve my soft
skills which are required for an engineer in his professional life. I went to many sub
divisions under CEB.
I could learn about the generation criteria of Sri Lanka such as thermal and hydro,
machineries under the generation part, transmission methods and maintenance works
carried out by CEB and the services which are given by the CEB to their customers and the
different functions related with different departments or sections.
At the CEB, I had some chances to get hands on experience with the tools, cables, hardware,
etc. Thus the project consisted mostly site visits thus involved lot of practical works.
I could learn the things by asking questions and demonstration with the help of engineers.
I could work with many people like engineers, electrical superintendents, technical offers,
non-technical staff etc.
This was my first experience as an electrical trainee Engineer. At the end of the training I
was able to collect lot of experiences regarding practical engineering, professionalism and
management.

52. 44
4.2 Conclusion
Industrial training plays a vital role in the overall engineering undergraduate curriculum in
integrating the skills, the knowledge and the attitudes about the industry of the
undergraduate. I've got a good opportunity to have my second industrial training in CEB.
As an engineering student of University of Ruhuna, I took a lot of practical knowledge
about power area and its technologies when I was in the CEB. During this valuable period
I was able to take so much experiences and theoretical knowledge.
I got the more experience how to work and deal with company staff, sub-contractors. Here
I should mention that I was able to get an opportunity to work with mechanics, technical
officers, engineers and share their knowledge and experiences. Those things gave me a
really good training as an engineering undergraduate.
Finally I would like to mention that the three month in training experience given to us as a
result of the dedication and commitment of a large group of people and it has been a rather
successful one which provided basic foundation for an Engineering undergraduate to
launch into the industry and start a successful carrier.

53. 45
References
[1] Official website of Ceylon Electricity Board, www.ceb.lk
[2] Annual reports of CEB
[3] Wikipedia, www.wikipedia.org
[4] Presentations from CEB divisions

54. 46
List of Corrections
No Page No Examiner’s comment Correction done
1 i Improper word is used. Proper word was included.
2 ii Names are not included in
acknowledgement.
Names were inserted to the
acknowledgement.
3 iii, iv Topics which does not have
number included in table of
content.
Topics which does not have
number were removed.
4 viii Lot of abbreviations in the
content are missing.
The missing abbreviations were
included.
5 3 Grammar mistake Grammar mistake was corrected
6 6 Table number not mentioned. Table number was included.
7 16 Letters within the image is not
clear.
A cleared image was included.
8 17 Image size is small. Image was enlarged.
9 19 Grammar mistake Grammar mistake was corrected
10 22 Spelling mistake in a word Spelling mistake was corrected.
11 23 Short form included in title Full form of the word was
included.
12 26 Image should be more clear. A clear image was inserted.
13 27 Image size is small. Image was enlarged.
14 30 Header row of table not included Header row for the table was
included.
15 41 Subscription mistake. Mistake was corrected.
16 42 Need more details for
management.
More details were added.
17 43 Summary not enough. More details were included in
summary.
18 44 Reference not included within
the content
Reference was included within the
content.