A practicum report on Power Generation and Supply System of Summit 156 MW Power Plant

1. 1
A practicum
report on
Power Generation and Supply System of Summit
156 MW Power Plant
Student’s Name
Md. Zafor Sadak
Student ID: 11105189

2. 2
Power Generation and Supply System of Summit
156 MW Power Plant
Md. Zafor Sadak
Student ID.: 11105189
Program: BSEEE
---------------------- ---------------------------- ----------------------------
S. M. Rezaul Karim Dr. Bishwajit Saha Dr. Md. Shariful Islam
Supervisor Coordinator Chairperson
Department of Electrical and Electronics Engineering
IUBAT – International University of Business Agriculture and Technology

3. 3
List of Figure
Figure1.6.1: summit power plant…………………………………………………………9
Figure 3.1.1: Single Line Diagram of summit power plan………………………………14
Figure 3.3.1.1: Diesel Electric Power Plant……………………………………………...18
Figure 3.4.1.1: Diesel Engine……………………………………………………………19
Figure 3.4.2.1: Engine Fuel Supply System……………………………………………..20
Figure 3.4.3.1: Engine Exhaust System………………………………………………….21
Figure 3.4.4.1: Engine Cooling System………………………………………………….23
Figure 3.4.6.1: Engine Lubrication System…………………………………………….27
Figure 4.1.1: 132 kV Online Grid Supply Diagram……………………………………..29
Figure 4.1.1.1: Power Transformers……………………………………………………..30
Figure 4.1.2.1: Current Transformer (CT)………………………………………………35
Figure 4.1.4.1: Potential Transformers (PT)………………………………......................39
Figure 4.1.7.1: Insulators………………………………………………………………...40
Figure 4.1.7.2: Suspension Type Insulators……………………………………………....41
Figure 4.1.7.3: Pin Type Insulator……………………………………………………….43
Figure 4.1.7.4: Strain Insulator…………………………………………………………..44
Figure 4.1.10.1: Underground Cable…………………………………………………….47
Figure 4.2.1: 3- Conductor Cable………………………………………………………..48
Figure 4.5.1: Zinc oxide Arrester………………………………………………………...52

4. 4
List of Table:
Table 2.1: List of summit power plant ltd………………………………………………..11
Table 4.1: Uses of CTs in Different Purposes…………………………………………...31
Table 4.2: Uses of PTs in Different Purposes……………………………………………34
Table of Contents:
Chapter 1 Introductory Part
1.1 Source of the Report…………………………………………………………………..6
1.2 Broad Objective……………………………………………………………………...6
1.3 Specific Objective……………………………………………………………………6
1.4 Scope…………………………………………………………………………………7
1.5 Limitation……………………………………………………………………………..7
1.6 Background……………………………………………………………………………9
1.7 Methodology…………………………………………………………………………..9
1.8 Vision………………………………………………………………………………….9
1.9 Mission………………………………………………………………………………...9
1.10 Primary Data………………………………………………………………………..10
Chapter 2 Organization
2.1 Introduction………………………………………………………………………10-11
2.2 Power Plant Authorized By Summit Power Limited………………………………..11
2.3 Summit Purbanchal Power Company Limited (SPPCL)……………………………12
2.4 Organogram………………………………………………………………………….12
2.5 Key Factors…………………………………………………………………………..13
Chapter 3 power Generation

5. 5
3.1 Introduction …………………………………………………………………………14
3.2 Components of an Electric Power System…………………………………………...15
3.3 Power Plant………………………………………………………………………….15
3.3.1 Diesel Electric Power Plant……………………………………………………16
3.3.2 Basic Principal of Diesel Electric Power Plant………………………………...17
3.4 Main Components of Diesel Electric Power Plant:………………………………….18
3.4.1 Diesel Engine…………………………………………………………………..18
3.4.2 Engine Fuel Supply System………………………………………………...19-20
3.4.3 Engine Air Intake System…………………………………………………..20-21
3.4.4 Engine Exhaust System, Engine Cooling System………………………….21-22
3.4.5 Engine Lubrication System…………………………………………………….22
3.4.6 Engine Lubrication System……………………………………………………23
3.4.7 Engine Starting System………………………………………………………...24
3.4.8 AC or DC Generators…………………………………………………………..25
Chapter 4: 132 kV Grid Supply System
4.1 Introduction
4.1.1 Power Transformer…………………………………………………………….28
4.1.2 Instrument Transformer………………………………………………………..29
4.1.3 Current Transformer (CT)………………………………………………….29-34
4.1.4 Potential Transformer (PT)…………………………………………………34-37
4.1.5 Bus bar.. ……………………………………………………………………37-38
4.1.6 Transmission and Distribution…………………………………………………38

6. 6
4.1.7 Insulators…………………………………………………………………..38-43
4.1.8 Isolators………………………………………………………………………..44
4.1.9 Auxiliary Systems …………………………………………………………….44
4.1.10 Underground Cables ……………………………………………………..44-46
4.2 Construction of 3- Conductor Cable.……………………………………………..47-48
4.3 Insulating Materials for Cables.………………………………………………...49-51
4.4 Classification of Cables: …………………………………………………………..51
4.5 Zinc oxide Arrester.………………………………………………………………….52
4.6 Operation Surveillance of Arrester: …………………………………………………54
Chapter 5 Conclusion
5.1 Limitations…………………………………………………………………………...55
5.2 Recommendation…………………………………………………………………….56
5.3 Conclusion…………………………………………………………………………...57
References

7. 7
Chapter 1: Introductory Part
1.1 Source of the Report
As a partial fulfillment of Bachelor of Science in Electrical & Electronics Engineering
program I have done this practicum report. My report entitled as “Power generation and
supply system ” in Summit Power Ltd. Basis on this three months duration practical
experience I have done this report and I have worked under the instruction of Engr. Mr.
Abdul Hakim,
1.2 Broad Objective
The main objectives are to extrovert my theoretical knowledge to the practical field with
adequate conceptualization and understanding the performance of the parameters in case
of Power Generation, Operation, Maintenance and Troubleshooting of Engine, Radiator,
Control Panel, Transformer, Switchyards etc.
1.3 Specific Objective
The specific objectives of this report include:
 Study on power generation and supply system.
 Identify the different types of problem which arise for generation and substation.
 Troubleshooting and isolate the probable problems occurred in power generation and
supply system.
 Suggest probable solution of the identified problem.
 Study on Diesel generator, Transformer, Switchyards
 Maintenance of Electrical Machines (LV & MV) and Equipment’s

8. 8
1.4 Scope
This report will cover the types of machinery used in Summit Gazipur power plant
152MW Diesel Engine Power Plant, The scope of power generation & transmission
system ,the operating and controlling of these machines, Transformer, Power Factor
Improvement, troubleshooting, switchyards and its protection systems, what equipment is
placed in which zone, how the equipment has been synthesized etc.
1.5 Limitation
I have some limitation during my practicum in the plant. Limitation is that
 Here engineers & staffs have no huge time to give vast information about it.
 I Can’t touch sensitive instrument,
 Power plant is the place of vast knowledge of engineering. In this report, not all
things can highlight deeply because of duration of time.
1.6 Background
The Summit Group is one of the leading private sector conglomerates of Bangladesh,
comprising more than twenty business units ranging from power to shipping to
communications and currently generating 792 MW of electricity and another 393 MW is
under construction. Summit Power Limited (SPL), a subsidiary of Summit Group is the
first Bangladeshi Independent Power Producer (IPP) in Bangladesh in private sector
providing power to national grid. SPL was incorporated in Bangladesh on March 30,
1997 as a Private Limited Company. On June 7, 2004, the Company was converted into
Public Limited Company under the Companies Act 1994.
Today Summit Power Limited owns and operates 11 (eleven) power plants at different
locations across the country having a total capacity of 317 MW. Our power plants are
equipped with engines manufactured by world famous technotex companies, i.e. Wartsila
– Finland, Caterpillar - USA, and GE Jenbacher, Austria. All of its power plants run 24
hours a day to support the national grid. As per private sector power generation policy of
Bangladesh, Summit sells electricity to the Bangladesh Power Development Board

9. 9
(BPDB) and Bangladesh Rural Electrification Board (BREB) only. Due to the practice of
Integrated Management System (IMS) to run the day-to-day business operation, the
Company has been certified by ISO 9001: 2008 - Quality Management System, ISO
14001: 2004 - Environmental Management System and OSHAS 18001: 2007 -
Occupational Health and Safety Assessment System.
Apart from three existing subsidiaries (Summit Purbanchol Power Company Limited,
Summit Uttaranchol Power Company Limited and Summit Narayanganj Power Limited),
Summit Power Limited holds 17.64% ownership of Khulna Power Company Limited
(KPCL) and 30% of Summit Meghnaghat Power Company Limited. That means 153 (50
+ 103) MW (approximately) has been added with that of SPL’s 317 MW, being the total
capacity of 470 MW. This fast-growing company has set a mission to expand the
company with a power generation capacity to the tune of a modest 20% of the electricity
requirement in Bangladesh. In the way to this mission to enlighten the nation, recently,
the Company is implementing two new power plants with a total generation capacity of
165 MW.
Due to its Management’s dedication, integrity and leadership, the Company has been
applauded locally and internationally by several awards at various times, i.e. – Best Fast
Track Power Project Award by Asian Power Awards, International Star for Leadership in
Quality Award by Business Initiative Directions (BID), Best Presented Accounts and
Corporate Governance Disclosures Awards by SAFA, ICAB National Award for Best
Published Accounts and Reports in Manufacturing Sector, ICMAB Best Corporate
Award in Power Sector, ICSB National Award for Corporate Governance Excellence in
General Manufacturing.

10. 10
Figure1.6.1: summit power plant
1.7 Methodology
Both primary and secondary data are being collected for the purpose of this report. The
report is concentrated in Summit Gazipur 152MW Summit power plant LTD.
1.8 Vision
To provide quality & uninterrupted electricity to the vast majority of rural Bangladesh
for their personal, social & economic development
1.9 Mission
Empowering Bangladesh, we can & we will. To expand the company into a power
generation capacity to the tune of 1000 MW that is 20% of the electricity requirement of
Bangladesh and maintains that level.’

11. 11
1.10 Primary Data
Primary Data are collected from the books about power plants, the User Manual to the
Engineers, Technicians of the company, official documents of the company and plant
Operation Manuals. The author of the report is directly working in the O&M unit of
Summit Power Ltd. and has extensive expertise in the O&M activities, so it was easier
for him to observe the system closely and collect necessary information to prepare the
report.
Chapter 2: Organization
2.1 Introduction
Summit Power Limited (SPL), sponsored by Summit Group, is the first Bangladeshi
Independent Power Producer (IPP) in Bangladesh in private sector providing power to
national grid. SPL was incorporated in Bangladesh on March 30, 1997 as a Private
Limited Company. On June 7, 2004 the Company was converted to Public Limited
Company under the Companies Act 1994. Summit Power Limited in 2001, has
successfully established three power plants of 11 MW capacity each, for sale of
electricity to Rural Electrification Board (REB) on Build, Own and Operate basis at
Savar, Narsingdi and Comilla. During 2006 and 2007 in each of the above three places,
2nd unit was commissioned enhancing the capacity of SPL to 105 MW. In 2009 SPL
with its 99% owned two subsidiaries has established 4 new power plants raising its
capacity to 215 MW. In 2011 SPL has commissioned another power plant of 102 MW
capacities at Narayanganj under Summit Narayanganj Power Limited, In the year 2011
Summit Power Limited has consolidated its position further by acquiring 53,955,326
numbers of ordinary shares of Khulna Power Company Limited (KPCL). It gives SPL the
status of 18.7% of the ownership of KPCL and with that status an additional capacity of
50 MW (approximately) has been added with that of SPL being the total capacity of 367
MW.

12. 12
Considering the immense opportunities, the company is striving to establish more power
plants around the country. The fast-growing company has set a mission to expand the
company with a power generation capacity to the tune of 1000 MW, which is a modest
20% of the electricity requirement in Bangladesh.
The management of the company is very dynamic and working proactively in a
challenging environment and is committed to act as a leading organization in the field of
power generation through its exceptional customer service and technical competence.
2.2 Power generation capacity of SPL
SPL generates electric power energy from its seven generating stations (Power Stations)
and supply them to the individual clients as per contract made with them.
Serial Number. Name of Power Plant Capacity
1 Gazipur Power Station 156MW
2 Chandina Power Station 24.5MW
3 Jangalia Power Station 33MW
4 Maona Power Station 33MW
5 Madhabdi Power Station 33.5MW
6 Ashulia Power Station 44.75MW
7 Rupganj Power Station 33MW
8 Uttaranchol Power Station 11MW
Table 2.1: List of summit power plant ltd

13. 13
2.3 Summit Gazipur Power Company Limited (SPPCL)
Summit Gazipur Power Company Limited (SPPCL), sponsored by Summit Group
and a subsidiary of Summit Power Limited (SPL), is one of the leading Bangladeshi
Independent Power Producer (IPP) in Bangladesh in private sector providing power to
national grid. SPPCL was incorporated in Bangladesh on August 15, 2007 as a Private
Limited Company.
Summit Gazipur Power Company Limited in the year 2016 has successfully established
two power plants of 450 MW capacity each, for sale of electricity to Rural Electrification
Board (REB) and Bangladesh Power Development (BPDB) on Build, Own and Operate
basis at Rupganj, Narayanganj and Jangalia, Comilla respectively.
2.4 Organogram:
Gazipur,Maona,Ashulia,Rupgonj power plants
(One plant with one control room)

14. 14
2.5 Key Factors
 This152 MW Natural HFO based Power plant is established on 3.52 decimals
land at Gazipur.
 This year, the Company will get 876 hours i.e. 36.5 days for full plant shutdown
for the scheduled and unscheduled outages.
 The heat rate of this plant is 8299KJ/KWh
 As Gazipur is near to Dhaka, which is the largest load centre of the country,
electricity generated by the plant is transmitted to in and around greater Gazipur
area through nearby 33kV grid substation.
 The site can be accessed by Dhaka at Gazipur. From Dhaka, the site is
approximately 21 km away by road.
 The plant consists of 4 Wartsila make 18V15 reciprocating type lean Diesel
Engines. The engine is of the four strokes, direct injected, trunk piston, turbo
charged and intercooled design.
 Operation software consists of Wartsila Engine Control System.
 Power dispatches are done as per provision of the PPA. The Plant is connected
with the nearby 33kV Substation of PBS. Through this substation, electricity
generated by the plant is distributed to the greater Gazipur area.It is assumed that
Gazipu plant will continue its power generation over 90% load factor based on the
project cost factors of the plants. The total generation capacity for the plant is
152MW.

15. 15
Chapter 3: Power Generation
3.1 Introduction
In this modern age, we can realize the demand of electricity when load shedding is
occurred. The increasing demand of electricity in our day to day life as well as in our
commercial and industrial purposes necessitates producing bulk electric power producing
units. To meet the increasing demand of electricity, Diesel based power plant are playing
an important role as the supply of Diesel is available in Bangladesh. In this power plant
they use HFO and treatment it and make it engine fuel. Whatever, after generating the
power from the power station it goes to grid sub-station to transmit power . The
procedure of total electric power generation system with related apparatus from
generating station to grid is taken into consideration in this report.
Figure 3.1.1: Single Line Diagram of summit power plant

16. 16
The production of electricity is the more complex part of electric supply system. The total
electricity generation system is included many hard and tough procedures with proper
operation and control otherwise the whole system may damage as a result will cause
severe damages for the electrical equipments.
3.2 Components of an Electric Power System
A modern electric power system consists of six main components:
1. The power plant
2. A set of transformers to raise the generated power to the high voltages used on the
transmission lines
3. The transmission lines
4. The substations at which the power is stepped down to the voltage on the
distribution lines
5. The distribution lines
6. The transformer that lowers the distribution voltage to the level used by the
consumer’s equipments.
3.3 Power Plant
A Diesel power station (also known as Stand-by power station) uses a diesel engine as
prime mover for the generation of electrical energy. This power station is generally
compact and thus can be located where it is actually required. This kind of power station
can be used to produce limited amounts of electrical energy. The alternator converts
mechanical energy of the turbine into electrical energy .The output from the alternator is
given to the bus bar through transformer, circuit breakers and isolators. The diesel burns
inside the engine and the combustion process moves a fluid that turns the engine shaft
and drives the alternator. The alternator in turn, converts mechanical energy into
electrical energy.

17. 17
This type of electricity generating power station will probably be used a long time into
the future, due to a need for reliable stand-by electrical source for emergency situations.
However, diesel power plants emit green house gases that pollute the environment and
also require frequent servicing.
3.3.1 Diesel Electric Power Plant
A generating station in which diesel engine is used as the prime mover for the generation
of electrical energy is known as diesel power station. For generating electrical power, it is
essential to rotate the rotor of an alternator by means of a prime mover. The prime mover
can be driven by different methods. Using diesel engine as prime mover is one of the
popular methods of generating power. When prime mover of the alternators is diesel
engine, the power station is called diesel power station. The mechanical power required
for driving alternator comes from combustion of diesel. As the diesel costs high, this type
of power station is not suitable for producing power in large scale in our country. But for
small scale production of electric power, and where, there is no other easily available
alternatives of producing electric power, diesel power station are used.

18. 18
Figure 3.3.1.1: Diesel Electric Power Plant
3.3.2 Basic Principal of Diesel Electric Power Plant
Chemical Energy of Diesel ↔ Heat Energy ↔ Mechanical Energy ↔Electrical Energy

19. 19
3.4 Main Components of Diesel Electric Power Plant
1. Diesel Engine
2. Engine Fuel Supply System
3. Engine Air Intake System
4. Engine Exhaust System
5. Engine Cooling System
6. Engine Lubrication System.
7. Engine Starting System.
8. AC or DC Generators
3.4.1 Diesel Engine
Figure 3.4.1.1: Diesel Engine

20. 20
It is the main components used in diesel electric power plant for developing mechanical
power. This mechanical power we use to run the generator & produce electrical energy.
For producing the electrical energy the diesel engine is mechanically coupled to
generator. When the diesel fuel burning inside the engine, its start to produce a
mechanical power. The combustion of diesel fuel produces increased temperature &
pressure inside the engine. Due to this pressure gases are formed, this gas pushes the
piston inside the diesel engine, and then mechanical power is produced. With the use of
this mechanical power the shaft of diesel engine starts rotating.
3.4.2 Engine Fuel Supply System
Figure 3.4.2.1: Engine Fuel Supply System

21. 21
It consists of Fuel Storage Tank, Fuel Filter or Strainer, Fuel Transfer Pump, Day Tank,
Heaters & Connecting Pipes. First up all with the help of transportation facility available
(road, rail etc.) the diesel fuel stored in storage tank. Then this diesel fuel transfer to day
tank, the function of day tank is how much quantity of diesel required for 24 hours is
store. If the day tank is full or overflow occurs, then excessive diesel returned to storage
tank. The filter or strainer is used to purify diesel. With the help of fuel transfer pump the
diesel is transfer to day tank.
3.4.3 Engine Exhaust System
Figure 3.4.3.1: Engine Exhaust System

22. 22
These systems consist of silencers & connecting ducts. As the temperature of the exhaust
gases is sufficiently high, it is used for heating the fuel oil or air supplied to the diesel
engine. The exhaust gas is removed from engine, to the atmosphere by means of an
exhaust system. A silencer is normally used in this system to reduce noise level of the
engine.
3.4.4 Engine Cooling System
Figure 3.4.4.1: Engine Cooling System
The Diesel Engine Cooling System Consist of coolant pumps, water cooling towers or
spray pond, water treatment or filtration plant & Connecting Pipe Works. The heat

23. 23
produced due to internal combustion, drives the engine. But some parts of this heat raise
the temperature of different parts of the engine. High temperature may cause permanent
damage to the machine. Hence, it is essential to maintain the overall temperature of the
engine to a tolerable level. Cooling system of diesel power station does exactly so. The
cooling system is required to carry heat from diesel engine to keep its temperature within
safe limits. The water pump circulates water to cylinder of diesel engine to carry away
the heat. The cooling tower is used for the same water reused. The cooling system
requires a water source, water pump and cooling towers. The pump circulates water
through cylinder and head jacket. The water takes away
3.4.5 The cooling system can be classified into two types
1. Open Cooling System:
A Plant near the river may utilize the river water for cooling & discharging again the
hot water into river. This type of cooling system is known as open cooling system.
2. Closed Cooling System:
The Cooling Water is circulated again & again and only water lost due to leakage,
evaporation etc. is made up by taking make up water from supply source.

24. 24
3.4.6 Engine Lubrication System
Figure 3.4.6.1: Engine Lubrication System
Engine lubrication system consists of lubricating oil pump, oil tanks, filters,
coolers, purifiers & connecting pipes. This system provides lubricating oil to moving
parts of the system to reduce the friction between them wear & tear of the engine parts.
This system minimizes the water of rubbing surface of the engine. Here lubricating oil is
stored in main lubricating oil tank. This lubricating oil is drawn from the tank by means
of oil pump. Then the oil is passed through the oil filter for removing impurities. From
the filtering point, this clean lubricating oil is delivered to the different points of the
machine where lubrication is required the oil cooler is provided in the system to keep the
temperature of the lubricating oil as low as possible. It is then cooled through heat
exchanger by means of cold water and then it is fed to the engine.

25. 25
3.4.7 Engine Starting System
The function of starting system is to start the engine form stand still or cold conditions by
supplying compressed air. For starting a diesel engine, initial rotation of the engine shaft
is required. Until the firing start and the unit runs with its own power. For small DG set,
the initial rotation of the shaft is provided by handles but for large diesel power station.
Compressed air is made for starting. This system includes storage compressed air tank,
self starter, auxiliary engines & electrical motors (battery) etc.
Starting of Small Engine:
Small sets or small capacity of diesel engines are started manually
Starting with the help of Auxiliary Engine:
When it is started by auxiliary engine, the auxiliary engine is disengaged by the main
engine & started by hand. When it is warmed up, it is geared with the main engine so that
it will start to rotate. After that within, few seconds auxiliary engine disengaging
Starting with the help of batteries:
To start the electrical motor batteries are used, the motor is geared with diesel engine, it
will start rotating with the motor & will start in few seconds & as it picks up the speed
the motor gets disengaged automatically. In some cases the motor works as a generator,
this will further helps to charge the batteries.
Starting with the help of compressed air:
A large capacity (above 75kW) capacity diesel engines are started with the help of
compressed air. Diesel engines are started with the help of compressed air following
procedure adopted:
1. First up all open the compressed air valve, then starting lever operated.
2. First up all air should be cut off in first combustion. Then open ventilating valve. Start
the engine after two or three revolutions

26. 26
3.4.8 AC or DC Generator
Electrical generators are devices that convert mechanical energy into electric energy. The
mechanical energy in turn is produced from chemical or nuclear energy in various types
of fuel, or obtained from renewable sources such as wind or falling water.
Most alternators use a rotating magnetic field. In principle, any AC electrical generator
can be called an alternator, Alternators in power stations driven by steam turbines are
called turbo-alternators or primover.AC generator or Alternators operate at the same
fundamental principles of electromagnetic induction as d.c generator. They also consist
of an armature winding and magnetic field. But there is important difference between the
two. Whereas in d,c generators the armature rotates and the field system is stationary, the
arrangement in armature is just the reverse of it. In their case standard construction
consist of armature winding mounted on a stationary element called stator and field
windings on a rotating element called rotor.

27. 27
Chapter 4: 132 kV Grid Supply System
4.1 Introduction
Substation is an indispensible part of Power Plant. Substation is used for different
purposes. Mainly substation is used for transmission of power. Usually at SPL, generator
produces 11KV output voltage which is then increased up to 132KV by step-up transformer for
transmitting and reducing I2R loss purpose. Substation is also used for the maintenance of
auxiliary equipment of the plant. In this chapter, we will discuss the main parts of a substation
used in SPL. Figure shows the partial part of the substation at SPL where the Current
Transformers (CT), Power Transformers (PT), Isolators, Insulators are connected and arranged.
Below, different equipment of the substation is described from the collective perspective. GCB I
have visited the substation; there I saw different types of equipment to obtain our desired
voltage levels. Mainly substation is used for transmission of power. The equipments that
are used in the substation of SPL are as follows
 Power Transformer
 Instrument Transformer
 Current Transformer (CT)
 Potential Transformer (PT)
 Bus bar
 Transmission and Distribution
 Insulators
 Isolators
 Auxiliary Systems
 Underground Cables

28. 28
Figure 4.1.1: 132 kV Online Grid Supply Diagram

29. 29
4.1. Transformers
In SPL, I have seen two types of transformer. They are listed and described below:
 Power Transformer
 Instrument Transformer
4.1.1 Power Transformers
In SPL, I closely observed power transformers and they are generally installed for step up
or step down the voltage. For long line transmission high voltage is needed. In SPL, there
are total four power transformers in each unit. The purpose of using power transformers
are depended on how much voltage we need to step or step down. In SPL power station
yard, I have seen the transformer one is for stepping up the voltage from 11 kV to 132
kV. Voltage step up is required as the voltage drop occurs while transmitting voltage and
to keep this voltage in satisfactory level SPL used this power transformer to step up the
voltage. After generating 11 kV power the SPL steps it up to 132 kV and supplies to the
grid substation.Transformer-1 of the substation which is used for stepping up the
generated voltage from 11kV to 132 kV. This is a Δ-Y connected transformer. They are
also step down transformers tapped from transformer 2. Here, the voltage level is stepped
down from 11kV to 6.6 kV. Those transformers are used for auxiliary purpose of the
plant. This 6.6kV high voltage is not directly used for auxiliary purpose but is made
change as per demand to lowest nominal voltage need.

30. 30
Figure 4.1.1.1: Power Transformers
4.1.2 Instrument Transformer
During my internship I saw instrument transformers. There were two kinds of Instrument
Transformers. They are Current Transformer and Potential Transformer. Instrument
transformers are used for measuring and protection purposes. The different types of
instrument transformers are discussed below.
4.1.3 Current Transformer (CT)
In SPL during my intern period, I saw several current transformers. Current transformers
are mainly used for metering and protection. Usually we cannot use high current for
metering purpose. So we need to step down the current to a convenient value. Normally
in CT, primary side current is very high and secondary side is low. At SPL, the ratio is
800/1. Current Transformers are always connected in series with the 132 KV line. These
transformers are made in India by BHEL (Bharat Heavy Electricals Ltd.). the CT at SPL
substation. Apparently CT looks like wide circular cylinder and it is connected in series
with the transmission line I observe carefully.

31. 31
Figure 4.1.2.1: Current Transformer (CT)

32. 32
CT No. Ratio Class Burden Location Purpose
32,33,34 600/1A PS Switch Yard Over all Differential & REF
35,36,37 800/1A 5P20 20VA Switch Yard Over Current Prot. for GT
38 800/1A PS Gen. Trf.
Neutral
REF Protection
39 800/1A 5P20 20VA Gen. Trf.
Neutral
Stand by Earth Fault Protection
1,2,3 10000/1A PS Generator Area GRP M Differential Prot.
4,5,6 10000/1A 0.2 75VA Generator Area Metering Circuit
7,8,9 1000/1A PS Generator Area GRP R Differential Prot.
10,11,12 10000/1A 0.5 30VA Generator Area AVR
13,14,15 10000/1A PS Generator Area GRP M Differential Prot.
16,17,18 10000/1A PS Generator Area GRP R Differential Prot.
19,20,21 10000/1A PS Generator Area Over all Differential
NGT CT 300/1A PS Generator
Neutral
Earth fault protection
22,23,24 10000/1A PS MVUAT HT
Side
Over all Differential
25,26,27 1250/1A PS MVUAT HT
Side
Over Current Prot. for MVUAT
25,26,27 1250/1A PS MVUAT HT
Side
MVUAT Differential Protection
42,43,44 1250/1A PS MVUAT LT
Side
MVUAT Differential Protection
40 1250/1A PS MVUAT
Neutral Side
REF Protection
Table 4.1: Uses of CTs in Different Purposes

33. 33
Typical terms Used for Specifying a CT
Rated Primary Current: The value of current which is to be transformed to a lower
value. In CT parlance, the "load" of the CT refers to the primary current.
Rated Secondary Current: The current in the secondary circuit and on which the
performance of the CT is based. Typical values of secondary current are 1 A or 5 A. In
the case of transformer differential protection, secondary currents of 1/ √3 A and 5/ √3 A
are also specified.
Rated Burden: The apparent power of the secondary circuit in Volt-amperes expressed
at the rated secondary current and at a specific power factor (0.8 for almost all standards).
Accuracy Class: In the case of metering CT s, accuracy class is typically, 0.2, 0.5, 1 or 3.
This means that the errors have to be within the limits specified in the standards for that
particular accuracy class. The metering CT has to be accurate from 5% to 120% of the
rated primary current, at 25% and 100% of the rated burden at the specified power factor.
In the case of protection CT s, the CT s should pass both the ratio and phase errors at the
specified accuracy class, usually 5P or 10P, as well as composite error at the accuracy
limit factor of the CT.
Composite Error: The rms value of the difference between the instantaneous primary
current and the instantaneous secondary current multiplied by the turns ratio, under
steady state conditions.
Accuracy Limit Factor: The value of primary current up to which the CT complies with
composite error requirements. This is typically 5, 10 or 15, which means that the
composite error of the CT has to be within specified limits at 5, 10 or 15 times the rated
primary current.

34. 34
Short Time Rating: The value of primary current (in kA) that the CT should be able to
withstand both thermally and dynamically without damage to the windings, with the
secondary circuit being short-circuited. The time specified is usually 1 or 3 seconds.
Instrument Security Factor (Factor of Security): This typically takes a value of less
than 5 or less than 10 though it could be much higher if the ratio is very low. If the factor
of security of the CT is 5, it means that the composite error of the metering CT at 5 times
the rated primary current is equal to or greater than 10%. This means that heavy currents
on the primary are not passed on to the secondary circuit and instruments are therefore
protected. In the case of double ratio CT's, FS is applicable for the lowest ratio only.
Class PS/X CT: In balance systems of protection, CT s with a high degree of similarity
in their characteristics is required. These requirements are met by Class PS (X) CT s.
Their performance is defined in terms of a knee-point voltage (KPV), the magnetizing
current (Imag) at the knee point voltage or 1/2 or 1/4 the knee-point voltage, and the
resistance of the CT secondary winding corrected to 75C. Accuracy is defined in terms of
the turn’s ratio.
Knee Point Voltage: That point on the magnetizing curve where an increase of 10% in
the flux density (voltage) causes an increase of 50% in the magnetizing force (current).
Summation CT: When the currents in a number of feeders need not be individually
metered but summated to a single meter or instrument, a summation current transformer
can be used. The summation CT consists of two or more primary windings which are
connected to the feeders to be summated, and a single secondary winding, which feeds a
current proportional to the summated primary current. A typical ratio would be 5+5+5/
5A, which means that three primary feeders of 5 are to be summated to a single 5A
meter.
Core Balance CT (CBCT): The CBCT, also known as a zero sequence CT, is used for
earth leakage and earth fault protection. The concept is similar to the RVT. In the CBCT,
the three core cable or three single cores of a three phase system pass through the inner
diameter of the CT. When the system is fault free, no current flows in the secondary of

35. 35
the CBCT. When there is an earth fault, the residual current (zero phase sequence
current) of the system flows through the secondary of the CBCT and this operates the
relay. In order to design the CBCT, the inner diameter of the CT, the relay type, the relay
setting and the primary operating current need to be furnished.
4.1.4 Potential Transformers (PT)
In SPL, I saw several potential transformers. These transformers are used for measuring
and protection purpose. Usually protective relays need low voltage to operate. So we
need to convert the high voltage to low voltage. In fact, potential transformer is a step
down transformer. It indicates primary side voltage is high and secondary side voltage is
low. PT is used in parallel with the line. The ratio is 1200/1 of 132KV line. Potential
transformers used in SPL are made in India by BHEL. Figure 4.6 is the PT. It sometimes
creates confusion about which one is PT in between CT and PT as both looks more or
less same. But PT is connected in parallel with the transmission line .
Table 4.2: Uses of PTs in Different Purposes
PT No. Ratio Class Burden Location Purpose
1,2,3(Core1) 11KV/110V 3P 30VA PT
Cubicle
Protection
1,2,3(Core2) 11KV/110V 0.5 30VA PT
Cubicle
AVR
4,5,6(Core1) 11KV/110V 3P 30VA PT
Cubicle
Protection
4,5,6(Core2) 11KV/110V 0.5 30VA PT
Cubicle
Spare
7,8,9 11KV/110V 0.2 75VA PT
Cubicle
Metering &
Synchronizing Ckt
10,11,12(Core1) 11KV/110V 0.5 30VA GCB Synchronizing Circuit
10,11,12(Core2) 11KV/110V 0.5/3P 15VA GCB Spare

36. 36
Figure 4.1.4.1: Potential Transformers (PT)

37. 37
Typical Terms Used for Specifying (PT)
Rated Primary Voltage: This is the rated voltage of the system whose voltage is
required to be stepped down for measurement and protective purposes.
Rated Secondary Voltage: This is the voltage at which the meters and protective
devices connected to the secondary circuit of the voltage transformer operate.
Rated Burden: This is the load in terms of volt-amperes (VA) posed by the devices in
the secondary circuit on the VT. This includes the burden imposed by the connecting
leads. The VT is required to be accurate at both the rated burden and 25% of the rated
burden.
Accuracy Class Required: The transformation errors that are permissible, including
voltage (ratio) error and phase angle error. Phase error is specified in minutes. Typical
accuracy classes are Class 0.5, Class 1 and Class 3. Both metering and protection classes
of accuracy are specified. In a metering PT, the VT is required to be within the specified
errors from 80% to 120% of the rated voltage. In a protection PT, the PT is required to be
accurate from 5% up to the rated voltage factor times the rated voltage.
Rated Voltage Factor: Depending on the system in which the PT is to be used, the rated
voltage factors to be specified are different. The table below is adopted from Indian and
International standards
Temperature Class of Insulation: The permissible temperature rise over the specified
ambient temperature. Typically, classes E, B and F.
Residual Potential Transformer (RPT): RPTs are used for residual earth fault
protection and for discharging capacitor banks. The secondary residual voltage winding is
connected in open delta. Under normal conditions of operation, there is no voltage output
across the residual voltage winding. When there is an earth fault, a voltage is developed
across the open delta winding which activates the relay. When using a three phase RVT,

38. 38
the primary neutral should be earthed, as otherwise third harmonic voltages will appear
across the residual winding. 3 phase RVTs typically have 5 limb constructions.
Metering Units: 11kV metering units consist of one 3-phase PT and 2 CT's connected
together in a single housing. This can be used for three phase monitoring of energy
parameters. It is used with trivector meters and energy meters.
Operation Surveillance of PT
 Firstly check air breaker in secondary side of voltage transformer if wiring of
PT secondary circuit is disconnected.
 Forbid short circuit in secondary circuit.
4.1.5 Bus Bar
During my internship in SPL I observed Bus Bars. Bus bar is a bar or metal rod where
different types of lines such as transmission line, distribution line etc. operates at the
same voltage level. Bus bar is used as the common electrical bar. The incoming and
outgoing lines in a substation are connected to the bus bar. In SPL they used single bus
bar.
Single Bus Configuration
As the name suggests, it consist of a single bus bar and all the incoming and outgoing
lines are connected to it. At SPL, the reason why they have used Single Bus
Configuration is due to the fact that it has low initial cost, less maintenance needed and
simple operation. However, the disadvantage of single bus bar system is that if repair is
to be done on the bus bar or a fault occurs on the bus, there is a complete interruption of
the power supply as we were told.

39. 39
4.1.6 Transmission and Distribution
After generating power by SPL, the power is fed to grid substation. The Power Grid
Company of Bangladesh Limited (PGCB) receives the power from SPL and transmits
this power. During my intern, I have visited and observed the transmission system done
by PGCB. A substation receives electrical power from generating station via incoming
transmission lines and delivers electrical power via the outgoing transmission lines.
Overhead lines are used for transmission and distribution. Some components are used in
SPL which are given below.
4.1.7 Insulators
I saw different types of insulators in the substation of SPL which are used in power lines.
There are three types of insulators. Figure shows these insulators which are pointed for
identification purpose. And they are:
 Suspension type insulator
 Pin type insulator
 Strain Insulator

40. 40
Figure 4.1.7.1: Insulators
Suspension Type Insulators
The cost of pin type insulator increases rapidly as the working voltage is increased.
Therefore, this type of insulator is not economical beyond 33 kV. For high voltages (>33
kV), it is a usual practice to use suspension type insulator is shown in Fig4.1.7.2.
They consist of a number of porcelain discs connected in series by metal links in the form
of a string. The conductor is suspended at the bottom end of this string while the other end
of the string is secured to the cross-arm of the tower. Each unit or disc is designed for low
voltage, say 11 kV. The number of discs in series would obviously depend upon the
working voltage. For instance, if the working volt- age is 66 kV, then six discs in series will
be provided on the string.

41. 41
Figure 4.1.7.2: Suspension Type Insulators
Advantages:
 Suspension type insulators are cheaper than pin type insulators for voltages
beyond 33 kV.
 Each unit or disc of suspension type insulator is designed for low voltage, usually
11 kV. Depending upon the working voltage, the desired number of discs can be
connected in series.
 If anyone disc is damaged, the whole string does not become useless because the
damaged disc can be replaced by the sound one.
 The suspension arrangement provides greater flexibility to the line. The
connection at the cross arm is such that insulator string is free to swing in any
direction and can take up the position where mechanical stresses are minimum.
 In case of increased demand on the transmission line, it is found more satisfactory

42. 42
to supply the greater demand by raising the line voltage than to provide another
set of conductors. The additional insulation required for the raised voltage can be
easily obtained in the suspension arrangement by adding the desired number of
discs.
 The suspension type insulators are generally used with steel towers. As the
conductors run below the earthed cross-arm of the tower, therefore, this
arrangement provides partial protection from lightning.
Pin Type Insulator
The different part of pin type insulator is shown in Fig 4.1.7.3. As the name suggests, the
pin type insulator is secured to the cross-arm on the pole. There is a groove on the upper
end of the insulator for housing the conductor. The conductor passes through this groove
and is bound by the annealed wire of the same material as the conductor.
Pin type insulators are used for transmission and distribution of electric power at voltages
up to 33 kV. Beyond operating voltage of 33 kV, the pin type insulators become too
bulky and hence uneconomic

43. 43
Figure 4.1.7.3: Pin Type Insulator
Causes of Insulation Failure
Insulators are required to withstand both mechanical and electrical stresses. The latter
type is primarily due to line voltage and may cause the breakdown of the insulator. The
electrical breakdown of the insulator can occur either by flash-over or puncture. In
flashover, an arc occurs between the line conductor and insulator pin (i.e., earth) and the
discharge jumps across the air gaps, following shortest distance. Figure shows the arcing
distance for the insulator. In case of flash-over, the insulator will continue to act in its
proper capacity unless extreme heat produced by the arc destroys the insulator. In case of
puncture, the discharge occurs from conductor to pin through the body of the insulator.
When such breakdown is involved, the insulator is permanently destroyed due to
excessive heat. In practice, sufficient thickness of porcelain is provided in the insulator to
avoid puncture by the line voltage. The ratio of puncture strength to flashover voltage is
known as safety factor.

44. 44
Strain Insulator
When there is a dead end of the line or there is corner or sharp curve, the line is subjected
to greater tension. In order to relieve the line of excessive tension, strain insulators are
used. For low voltage lines (< 11 kV), shackle insulators are used as strain insulators.
However, for high voltage transmission lines, strain insulator consists of an assembly of
suspension insulators as shown in Fig 4.1.7.4.
Figure 4.1.7.4: Strain Insulator
The discs of strain insulators are used in the vertical plane. When the tension in lines is
exceedingly high, as at long river spans, two or more strings are used in parallel.

45. 45
4.1.8 Isolators
In substation we also saw the Isolators. It is the extra protection part of the system. It is
often desired to disconnect a part of the system for general maintenance and repairs. It is
accomplished by an isolator. Isolator does not have the arc extinction capacity. It operates
under no load condition. It does not have any specified current breaking capacity or
current making capacity. Isolator not even used for breaking load currents. While opening
a circuit we have to open the circuit breaker first, and then we can open the isolator.
While closing circuit, the isolator is closed first, then circuit breakers.
4.1.9 Auxiliary Systems
During our intern period we saw different types of auxiliary systems used in SPL. The
systems are Lube Oil pumps, Outdoor lighting and receptacles, Control house, Heating
and ventilation, Chiller Air conditioning, Battery charger input and Motor-operated
switches etc. For these auxiliary purposes, SPL take power from Grid and Transformer 3,
4.
4.1.10 Underground Cable
An underground cable essentially consists of one or more conductors covered with
suitable insulation and surrounded by a protecting cover. In SPL’s substation, I saw these
cables for the grounding, metering and internal connection purpose.
The cable shown in figure 5.8 is actually an XLPE cable ranges from 6.6kV to 33kV in
voltage rating. XLPE cables use cross linked polyethylene as insulator and this equalizes
the electrical stress of the cables. By means of this underground cable the generated
power of SPL is transmitted in grid substation of PGCB.
Although several types of cables are available, the type of cable to be used will depend
upon the working voltage and service requirements. In general, a cable must fulfill the

46. 46
following necessary
 The conductor used in cables should be tinned stranded copper or aluminum of
high conductivity. Stranding is done so that conductor may become flexible and
carry more current.
 The conductor size should be such that the cable carries the desired load current
without overheating and causes voltage drop within permissible limits.
 The cable must have proper thickness of insulation in order to give high degree of
safety and reliability at the voltage for which it is designed.

47. 47
Figure 4.1.10.1: Underground Cable
The cable must be provided with suitable mechanical protection so that it may
withstand the rough use in laying it.
 The materials used in the manufacture of cables should be such that there is complete
chemical and physical stability throughout.

48. 48
4.2 Construction of 3- Conductor Cable
The construction of a 3-conductor cable which is used usually for 132 kv system’s
transmission. The various parts are:
Figure 4.2.1: 3- Conductor Cable
Cores or Conductors: A cable may have one or more than one core (conductor)
depending upon the type of service for which it is intended. For instance, the 3-conductor
cable shown in Fig. 4.2.1 is used for 3-phase service. The conductors are made of tinned
copper or aluminum and are usually stranded in order to provide flexibility to the cable.
Insulation: Each core or conductor is provided with a suitable thickness of insulation,
the thickness of layer depending upon the voltage to be withstood by the cable. The

49. 49
commonly used materials for insulation are impregnated paper, varnished cambric or
rubber mineral compound.
Metallic Health: In order to protect the cable from moisture, gases or other damaging
liquids in the soil and atmosphere, a metallic sheath of lead or aluminum is provided over
the insulation.
Bedding: Over the metallic sheath is applied a layer of bedding which consists of a fibrous
material like jute or hessian tape. The purpose of bedding is to protect the metallic sheath
against corrosion and from mechanical injury due to armoring.
Armoring: Over the bedding, armoring is provided which consists of one or two layers of
galvanized steel wire or steel tape. Its purpose is to protect the cable from mechanical injury
while laying it and during the course of handling. Armoring may not be done in the case of
some cables.
Serving: In order to protect armoring from atmospheric conditions, a layer of fibrous
material (like jute) similar to bedding is provided over the armoring. This is known as
serving. It may not be out of place to mention here that bedding, armoring and serving are
only applied to the cables for the protection of conductor insulation and to protect the
metallic sheath from mechanical injury.

50. 50
4.3 Insulating Materials for Cables
The satisfactory operation of a cable depends to a great extent upon the characteristics of
insulation used. Therefore, the proper choice of insulating material for cables is of
considerable importance. In general, the insulating materials used in cables should have
the following properties:
 High insulation resistance to avoid leakage current.
 High dielectric strength to avoid electrical breakdown of the cable.
 High mechanical strength to withstand the mechanical handling of cables.
 Non-hygroscopic i.e., it should not absorb moisture from air or soil. The moisture
tends to decrease the insulation resistance and hastens the breakdown of the cable. In
case the insulating material is hygroscopic, it must be enclosed in a waterproof
covering like lead sheath.
 Non-inflammable.
 Low cost so as to make the underground system a viable proposition.
 Unaffected by acids and alkalis to avoid any chemical action.
No one insulating material possesses all the above mentioned properties. Therefore, the
type of insulating material to be used depends upon the purpose for which the cable is
required and the quality of insulation to be aimed at. The principal insulating materials used
in cables are rubber, vulcanized India rubber, impregnated paper, varnished cambric and
polyvinyl chloride.
Rubber: Rubber may be obtained from milky sap of tropical trees or it may be produced
from oil products. It has relative permittivity varying between 2 and 3, dielectric strength
is about 30 kV/mm and resistivity of insulation is 1017 cm. Although pure rubber has
reasonably high insulating properties, it suffers from some major drawbacks viz., readily
absorbs moisture, maximum safe temperature is low (about 38ºC), soft and liable to
damage due to rough handling and ages when exposed to light. Therefore, pure rubber
cannot be used as an insulating material.

51. 51
Vulcanized India Rubber (V.I.R.): It is prepared by mixing pure rubber with mineral
matter such as zinc oxide, red lead etc., and 3 to 5% of sulphur. The compound so formed
is rolled into thin sheets and cut into strips. The rubber compound is then applied to the
conductor and is heated to a temperature of about 150ºC. The whole process is called
vulcanization and the product obtained is known as vulcanized India rubber. Vulcanized
India rubber has greater mechanical strength, durability and wear resistant property than
pure rubber. Its main drawback is that sulphur reacts very quickly with copper and for
this reason, cables using VIR insulation have tinned copper conductor. The VIR insulation
is generally used for low and moderate voltage cables.
Impregnated paper: It consists of chemically pulped paper made from wood chippings
and impregnated with some compound such as paraffinic or naphthenic material. This type
of insulation has almost superseded the rubber insulation. It is because it has the
advantages of low cost, low capacitance, high dielectric strength and high insulation
resistance. The only disadvantage is that paper is hygroscopic and even if it is
impregnated with suitable compound, it absorbs moisture and thus lowers the insulation
resistance of the cable. For this reason, paper insulated cables are always provided with
some protective covering and are never left unsealed. If it is required to be left unused on
the site during lying, its ends are temporarily covered with wax or tar. Since the paper
insulated cables have the tendency to absorb moisture, they are used where the cable route
has a few joints. For instance, they can be profitably used for distribution at low voltages in
congested areas where the joints are generally provided only at the terminal apparatus.
However, for smaller installations, where the lengths are small and joints are required at a
number of places, VIR cables will be cheaper and durable than paper insulated cables.

52. 52
Varnished cambric: It is a cotton cloth impregnated and coated with varnish. This type
of insulation is also known as empire tape. The cambric is lapped on to the conductor in
the form of a tape and its surfaces are coated with petroleum jelly compound to allow for
the sliding of one turn over another as the cable is bent. As the varnished cambric is
hygroscopic, therefore, such cables are always provided with metallic sheath. Its dielectric
strength is about 4 kV/mm and permittivity is 2.5 to 3.8.
Polyvinyl chloride (PVC): This insulating material is a synthetic compound. It is
obtained from the polymerization of acetylene and is in the form of white powder. For
obtaining this material as cable insulation, it is compounded with certain materials known
as plasticizers which are liquids with high boiling point. The plasticizer forms a gell and
renders the material plastic over the desired range of temperature. Polyvinyl chloride has
high insulation resistance, good dielectric strength and mechanical toughness over a wide
range of temperatures. It is inert to oxygen and almost inert to many alkalis and acids.
Therefore, this type of insulation is preferred over VIR in extreme environmental
conditions such as in cement factory or chemical factory. As the mechanical properties
(i.e., elasticity etc.) of PVC are not so good as those of rubber, therefore, PVC insulated
cables are generally used for low.
4.4 Classification of Cables
Cables for underground service may be classified in two ways according to (i) the type of
insulating material used in their manufacture (ii) the voltage for which they are
manufactured. However, the latter method of classification is generally preferred,
according to which cables can be divided into the following groups:
1. Low-tension (L.T.) cables — up to 1000 V
2. High-tension (H.T.) cables — up to 11,000 V
3. Super-tension (S.T.) cables — from 22 kV to 33 kV
4. Extra high-tension (E.H.T.) cables — from 33 kV to 66 kV
5. Extra super voltage cables — beyond 132 kV

53. 53
4.5 Zinc oxide Arrester
The earthling screen and ground wires can well protect the electrical system against
direct lightning strokes but they fail to provide protection against travelling waves which
may reach the terminal apparatus. The lightning arresters or surge diverters provide
protection against such surge.
A lightning arrester or a surge diverter is a protective device which conducts the high
voltage surges on the power system to the ground.
Figure 4.5.1: Zinc oxide Arrester

54. 54
Description:
Lightning arrester is to protect electrical equipment in power System from damage of
over voltage and high voltage Company with full set of advanced production and testing
equipment, product quality in the industry to stay ahead, have passed ISO9001-2000, CE,
ROHS certification and so on.
Characteristic:
 Smaller in size, Light in weight, High withstands collision, Flexible installation,
particularly suitable for use in the switch cabin.
 Special structure, the overall compression molding, no air gap, high sealing
performance, moisture-proof explosion-proof.
 Large creep age distance good hydrophobic, strong resistance to incompetence,
stable performance and reduce operation and maintenance.
 High performance zinc oxide arrestor, high-capacity, low-leakage.
 Real with DC reference voltage, square-wave-pass flow capacity and high current
tolerance is higher than the national standard.

55. 55
4.6 Operation Surveillance of Arrester
 Grounding line should be in good condition and connected to earth reliably;
 Porcelain bushing should not have any crack, fragmentation and discharge
phenomena.
 Should entirely check all arresters and actions of discharge recorder after thunder
storm, then record them.
Chapter 5: Concluding Part
5.1 Limitations
 During my internship one generator unit was turned off. This is why I could not
observe full load of the power station.
 The time of the internship was too short for which I could not learn all the
sections thoroughly.
 Before the internship I did not have any academic knowledge about the
mechanical section of the power plant, for which I faced some problems during
internship.

56. 56
5.2 Recommendations
1) The company can use small type of turbine in the exhaust pipe which may
produce small amount of electricity each of exhaust pipe which can drive the
auxiliary equipment properly without consuming the generated power.
2) Need more storage of spare parts. Because all equipment are imported. During
inspections some fault are noticed. If we have more storage then we can get the
faultless parts without wasting of time.
3) The plant incoming gas line from Titas which is 4 bars and sometimes it
become less than 3 bars. It should be raised to 12 bars for getting high pressure.
4) If the auxiliary demand can be reduced by using solar system then the plant
could distribute more power than usual. It is possible by using high efficient
equipment and motors in auxiliary needs.

57. 57
5.3 Conclusion
Gazipur Power Plant is one of the private power plants in Bangladesh. Considering the
current electricity crisis in Bangladesh it is very much important that private investment
in power sector takes place at a rapid rate. Present power capability is not sufficient for
our country. In this regard the government has a lot to do to ensure smooth running of the
power sector in private sector. My experience during the short time training at Gazipur
power plant, has not only increased my depth of knowledge, but also has given me the
feeling of challenges faced in engineering profession. Thanks to Summit Power Limited
for providing me with the opportunity to conduct an internship in their plant. I believe
that I can utilize this experience in my professional life.

58. 58
References:
[1] Gazipur plant operation manual.pdf
[2] Datasheet of SUMMIT Power Ltd.
[3] Principle of Power System-V.K Mehta & Rohit Mehta ch-2 pages (28-32).
[4] SUMMIT Power Ltd. (http://www.splbd.com/)
[5] http://www.sgipolytechnic.in/Notes/Electrical/SE_05.pdf
[6] https://www.electrical4u.com/diesel-power-station/
[7] http://www.electrical4u.com/electrical-transformer/buchholz-relay-in tr
[8] www.furukawa.co.jp/review/fr032/fr32_02.pdf
[9] https://www.wartsila.com/energy/solutions/multi-fuel-power-plants
[10] https://en.wikipedia.org/wiki/Diesel_(game_engine)
[11] https://www.electrical4u.com/electrical-power-transmission-system-and-network/
[12]http://www.projecttopics.info/Electronics/Reverse_Power_Protection_of_An_Alterna
tor.php