STUDY OF ELECTRICAL POWER GENERATION,TRANSMISSION & DISTRIBUTION IN BANGLADESH

8/10/2019 STUDY OF ELECTRICAL POWER GENERATION,TRANSMISSION & DISTRIBUTION IN BANGLADESH

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This Thesis is submitted in Partial Fulfillment for the

Requirement of the Degree of Bachelor of Science in

Electrical & Electronic Engineering

Course Code: EEE-499

STUDY OF ELECTRICAL POWER GENERATION,TRANSMISSION &

DISTRIBUTION IN BANGLADESH

Prepared By:

1. Jagadish Chandra Sutradhar ID # 112-0070-511

2. Md. Sharif Hossain ID # 112-0164-511

3. Syed Shawkat Aziz ID # 112-0011-511

4. Mohammad Ali Hasan ID # 112-0135-511

5. Md. Jakir Hossain ID # 122-0197-511


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STUDY OF ELECTRICAL POWER GENERATION, TRANSMISSION &

DISTRIBUTION IN BANGLADESH

A Project / internship / thesis report submitted to the department of EEE, Atish

Dipankar Biggayan O Projokti Bishawbiddaloy for partial fulfillment of the Degree

of B.Sc in Electrical and Electronic Engineering.

Submitted By:






Supervised By:

Marzia Hoque Signature :

Date:


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Declaration

It is here by declared that no part of this thesis bearers the copyright violation and no plagiarism

opted during the course of material preparation. The entire works has been planned and carried

out under the thesis supervisor of the honorable faculty member Marzia Haque department of

Electrical and Electronic Engineering, Atish Dipankar Biggayan O Projokti Bishawbiddaloy,

Dhaka, Bangladesh.

The content of this thesis is submitted by the groupName : Jagadish Chandra Sutradhar, ID #

112-0070-511, Name : Md. Sharif Hossain ID # 112-0164-511, Name : Syed Shawkat Aziz ID

# 112-0011-511, Name : Mohammad Ali Hasan ID # 112-0135-511, Name : Md. Jakir

Hossain ID # 122-0197-511.

Only for the fulfillment of the course ofSTUDY OF ELECTRICAL POWER

GENERATION, TRANSMISSION DISTRIBUTION IN BANGLADESH .And no part

of this is used anywhere for the achievement of any academic Degree or Certificate.

Jagadish Chandra Sutradhar

ID # 112-0070-511

Department of EEE

Syed Shawkat Aziz

ID # 112-0011-511

Department of EEE

Md. Sharif Hossain

ID # 112-0164-511

Department of EEE

Mohammad Ali Hasan

ID # 112-0135-511

Department of EEE

Md. Jakir Hossain

ID # 122-0197-511

Department of EEE


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Certificate

This is to certify that the B.Sc. thesis entitled STUDY OF ELECTRICAL POWER

GENERATION, TRANSMISSION DISTRIBUTION IN BANGLADESH

. submitted by

following group:

This is to certify that the B.Sc thesis entitled STUDY OF ELECTRICAL POWER GENERATION,

TRANSMISSION DISTRIBUTION IN BANGLADESH

submitted by following groupName

: Jagadish Chandra Sutradhar, ID # 112-0070-511, Name : Md. Sharif Hossain ID # 112-

0164-511, Name : Syed Shawkat Aziz ID # 112-0011-511, Name : Mohammad Ali Hasan ID# 112-0135-511, Name : Md. Jakir Hossain ID # 122-0197-511.

The thesis represents an independent and original work on the part of the

candidates. The research work has not been previously formed the basis for the

award of any Degree, Diploma, Fellowship or any other discipline.

The whole work of this thesis has been planned and carried out by this group

under the supervision and guidance of the faculty members of Atish Dipankar

Biggayan O Projokti Bishawbiddaloy, Bangladesh.

Marzia Hoque

LecturerDepartment of Electrical and Electronic EngineeringAtish Dipankar Biggayan O Projokti Bishawbiddaloy


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Transmittal

Date: 26/05/2014Faculty of Engineering

Department of EEEAtish Dipankar Biggayan O Projokti BishawbiddaloyDhaka, Bangladesh.

Subject: letter of transmittal.

Dear Sir,With due respect, we should like to inform you that is a great pleasure for us to submit the final

project on STUDY OF ELECTRICAL POWER GENERATION, TRANSMISSION &

DISTRIBUTION IN BANGLADESHfor Department of Electrical and Electronic Engineering

as requirement bachelor degree/ program. This project provided us with a practical exposure to

the overall working environment and very good experience which is prevailing in to professional

life. We came to know about many things regarding the current world on the concept of

Electronic Development. We have tried to our best to put through effort for the preparation of this

report. Any short coming or fault may arise as our unintentional mistake we will whole heartily

welcome for any clarification and suggestion about any view and conception disseminated

through this project.

We hope and strongly believe that this project will meet the requirement as well as satisfying your

purpose. We will available for any further classification in this regard.

Sincerely Yours,

ID # 112-0070-511

ID # 112-0164-511

ID # 112-0011-511

ID # 112-0135-511

ID # 122-0197-511


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APPORAVAL SHEET

This project title is STUDY OF ELECTRICAL POWER GENERATION, TRANSMISSION &

DISTRIBUTION IN BANGLADESH has been submitted to the following respected members of

the Board of Examiners of the Department of Electrical and Electronic Engineering in partial

fulfillment of the requirements of the degree of Bachelor of Department of Electrical and

Electronic Engineering by the following students.






As the supervisor I have approved this paper for submission.

.. ..

Marzia Hoque Md.Imam HossainProject Supervisor & Senior Lecturer & CoordinatorLecturer Department of EEEDepartment Of EEE Atish Dipankar Biggayan O AtishDipankar Biggayan O Projokti BishawbiddaloyProjokti Bishawbiddaloy


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ACKNOWLEDGEMENT

At first we would like to thank our Supervisor Marzia Haque

(Lecturer) for giving us the opportunity to work to under his supervision, the endless hours of

help, Suggestions, Advice and Support to keep us on track during the development of this thesis.

We also want to express gratitude to Mr. Md. Imam Hossainfor his support during our work on

this thesis.

Last, but not the least, we would like to thank our parents and family for making it possible for us

to study and for their constant help and support.

May, 2014







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ABSTRACT

In this modern world, the dependence on electricity is so much that it has become a part and

parcel of our life. The development of any country of the world is based on electricity and its

proper generation, transmission and distribution. For the proper utilization, it is required to

transmit and distribute the generating electrical power through the proper way.

For proper power generation, we have to consider the selection of power station according to the

site selection of the different power station and their advantage and disadvantage.

In this thesis work, we have discussed about different types of power station, their merits &

demerits, power generation in Bangladesh, power demand, installed capacity deficiency of power,

power plant under construction.

We have also discussed about the transmission and distribution system. Where has been included

mechanical design of transmission system, electrical design of transmission system, different

types of transmission loss, remedy of loss. For distribution system, we have included the bhurulia

distribution sub-station.

We think that, this study will be very helpful for better understanding about generation and

transmission system of Bangladesh.


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ABBREVIATIONS & NOTATIONS

BPDB : Bangladesh Power Development Board

PGCB : Power Grid Company of Bangladesh Ltd

DESA : Dhaka Electric Supply Authority

DESCO : Dhaka Electric Supply Company

REB : Rural Electrification Board

LDC : Load dispatch Centre

A.C : Alternating Current

D.C : Direct Current

KVA : Kilo Volt Ampere

Km : Kilometer

KV : Kilo Volt

KW : Kilo Watt

KWH : Kilo Watt Hour

HVDC : High Voltage Direct Current

CB : Circuit Breaker

GS : Generation Station

HEPS : Hydro Electric Power Station

DPS : Diesel Power Station

NPS : Nuclear Power Station

IPP : Independent Power Producer

EHV : Extra High Voltage


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CONTENTS

TABLE OF CONTENTS

Contents Page No.

Cover Page 1Initial Page 2Declaration 3Certificate 4

Transmittal 5Approval Sheet 6Acknowledgement 7Abstract 8Abbreviation & Notations 9Table of Contents 10List of Table 11List of Figure 12

CHAPTER-1: Introduction

1.1 Background 19

1.2 Objective of thesis 19

CHAPTER-2: Study of power generation system

2.1 Generation Station 20

2.2 Types of Generating Station 20

2.3 Steam power plant 20

2.3.1 Choice of site for Steam power plant 20


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2.3.2 Advantages of Steam power plant 21

2.3.3 Disadvantages of Steam power plant 21

2.3.4 Schematic arrangement of Steam power plant 21

2.3.5 Description of various section of Steam power plant 22

2.3.6 Typical Steam power plant 24

2.3.7 Efficiency of Steam power plant 34

2.4 Hydro-Electric power Station 34

2.4.1 Choice of site for Hydro-Electric power Station 35

2.4.2 Advantages of Hydro-Electric power Station 35

2.4.3 Disadvantages of Hydro-Electric power Station 36

2.4.4 Constituents of Hydro-Electric power Station 36

2.5 Nuclear power station 37

2.5.1 Choice of site for nuclear power station 37

2.5.2 Advantages of Nuclear power station 38

2.5.3 Disadvantages of Nuclear power station 38

2.5.4 Schematic arrangement of nuclear power station 38

2.6 Diesel power station 40

2.6.1 Choice of site for Diesel power station 40

2.6.2 Advantages of Diesel power station 40

2.6.3 Disadvantages of Diesel power station 40

2.6.4 Schematic arrangement of Diesel power station 41

2.7 Gas turbine power station 41

2.7.1 Advantages of Gas turbine power station 41

2.7.2 Disadvantages of Gas turbine power station 41

2.7.3 Schematic arrangement of Gas turbine power station 42

2.7.4 The main components of the plant 42


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CHAPTER-3: Power generation in Bangladesh

3.1 Generating voltage of different power station 44

3.2 Power demand 44

3.3 Load factor and Load management 44

3.4 Installed capacity 44

3.5 Owner Wise Daily Generation 45

3.5.1 Installed Capacity of BPDB Power Plants as on April 2014. 46


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CHAPTER-4: Transmission System of Bangladesh

4.1 Transmission System 52

4.2 Primary Transmission 52

4.2.1 Grid System 52

4.2.2 Grid substation 52

4.3 Secondary Transmission 53

4.4 Classification of overhead transmission line 53

4.5 Definition of important terms 53

4.6 Advantages of high voltage transmission system 54

4.7 Advantages and disadvantages of high voltage direct current system 55

4.8 Transmission system of different countries 55

4.8.1 Transmission system of India 55

4.8.2 Transmission system of Srilanka 56

4.8.3 Transmission system of Nepal 56

4.8.4 Transmission system of Pakistan 57

CHAPTER-5: Mechanical design of overhead transmission line

5.1 Properties of conductor materials 58

5.2 Conductors materials 58

5.3 Types of conductor 59

5.4 Line support 61

5.5 Types of line support 61

5.6 Insulators 62

5.7 Types of Insulators 62


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CHAPTER-6: Electrical design of overhead transmission line6.1 Electrical design aspects 656.2 Constant of transmission line 656.3 Characteristics of different transmission line 716.4 Transmission voltage level 76

6.5 Standardization of transmission voltage 776.6 Extra high voltage transmission 776.7 Protection system of transmission line 786.8 Protection components 786.9 LIST OF TRANSMISSION LINES IN BANGLADESH 79

6.9.1 Recent Completed Project for Transmission6.9 132 KV Transmission Lines 806.9.1 Recent Completed Project for Transmission 816.9.2 Hasnabad & Tongi 230 kV and Kalyanpur 132 kV S/s Construction (Hasnabad-

Aminbazar-Tongi & Haripur-Me82

6.9.3 Joydevpur-Kabirpur-Tangail 78 km 132 kV T/L & 3 S/s Extn. Project (Joydebpur-

Kabirpur-Tangail 132 kV

83

6.9.4 Ishurdi-Baghabari 54 km 230 kV T/L Construction (Ishurdi Baghabari-Serajgonj-Bogra 230 kV T/L Project)

83

6.9.5 On Going Project for Transmission400/230/132 Network Developmemt project (Trance-2)

84

6.9.6 Goalpara-Bagerhat 132 kV Double Circuit Transmission Line 846.9.7 Meghnaghat-Aminbazar 400 kV Transmission Line (NG1) 846.9.8 Construction & Extension of Grid Substations including transmission line facilities

(Phase-1)85

6.9.9 Aminbazar-Old Airport 230 kV Transmission Line and Associated Substations 856.9.10 Transmission Efficiency Improvement through Reactive Power Compensation at

Grid Substations and Reinforcement of Goalpara Substation85

6.9.11 Siddhirganj-Maniknagar 230 kV Transmission Line 866.9.12 132 kV Grid Network Development Project in Eastern Region. 866.9.13 National Power Transmission Network Development Project 866.9.14 Barisal-Bhola-Burhanuddin 230 kV Transmission Line Project 876.9.15 Grid Interconnction between Bangladesh(Bheramara) and India(Baharampur) 876.9.16 Two new 132/33 kV substations at Kulaura & Sherpur with interconnecting line 876.9.17 Bibiyana-Kaliakoir 400 KV and Fenchuganj-Bibiyana 230KV Transmission Line

(NG2)88

6.9.18 Haripur 360 MW Combined Cycle Power Plant and Associated Substation (PGCBPart)

88

6.10 Transmission line losses 88

6.10.1 Types of losses 88

6.10.2 Skin effect 89

6.11 Minimization of Transmission line losses 90

CHAPTER-7: Distribution System

7.1 Definition of Substation 91

7.2 Importance of Substation 91


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7.3 Equipment of electrical Substation 91

7.4 Classification of Substation 91

7.5 Definition of different equipments 92

7.5.1 Transformer 93

7.5.2 Power Transformer 93

7.5.3 Instrument Transformer 93

7.5.4 Isolator 94

7.5.5 Lighting arrester 95

7.5.6 Insulator 95

7.5.7 Bus-Bar 977.5.8 Circuit-Breaker 99

7.5.9 Basic principles of operation of circuit breaker 100

7.6 Different types of Circuit Breaker 100

7.6.1 Plain Breaker Oil circuit Breaker (POCB) 100

7.6.2Vacuum Circuit Breaker (VCB) 101

7.6.3 Sulphur Hexa Fluoride Circuit Breaker (SF6) 102

7.7 List of equipments of bhurulia sub-station 1047.8 Rating of different equipments 104

7.9 Single line diagram of bhurulia sub-station 106

7.9 Calculation of power factor for different feeder 107

CHAPTER-8: Future plan of Bangladesh

8.1 Power generation plan up to 2016 108

8.2 India Bangladesh transmission link 108

8.3 400 KV transmission line 108

CHAPTER-9: Discussion And Conclusion Reference

LIST OF FIGURE

Figure : 2.1 Schematic arrangement of a steam power station. 22

Figure : 2.2 Steam power plant 24

Figure : 2.3 Steam Generator 25


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Figure : 2.4 Turbo Generator 29

Figure : 2.5 Diagram of a typical water cooled surface condenser. 30

Figure : 2.6 A Ranking cycle with a two stage steam turbine and a single feed

water heater.

31

Figure : 2.7 Boiler feed water desecrator 32

Figure : 2.8 Schematic arrangement of a hydro-electric power station. 35

Figure : 2.9 Schematic Arrangement of a Nuclear power Station. 39

Figure : 2.10 Schematic Arrangement of a Diesel Power Plant 41

Figure : 2.11 Schematic arrangement of a gas turbine power plant. 42

Figure : 5.1 Conductor Section of AAC. 59

Figure : 5.2 (a): 37 Bobbin Stranding Machine (b) : 61 Bobbin Stranding Machine

(c) : Conductor Section of AAAC (d) : Conductor Section of ACSR

60

61

Figure : 5.3 Steel Tower 62

Figure : 5.4 Pin type Insulator 63

Figure : 5.5 Outside and inside constructional diagram of long rod insulators 64

Figure : 6.1 Equilateral Spacing (inductance). 67

Figure : 6.2 (a) Unsymmetrical Spacing (inductance).

(b) Unsymmetrical Lines (inductance).

68

Figure : 6.3 Equilateral Spacing (capacitance). 69

Figure : 6.4 Unsymmetrical Spacing (capacitance). 70

Figure : 6.5 Two port network. 72

Figure : 6.6 Short Transmission line. 72

Figure : 6.7 Medium Transmission Line. 73

Figure : 6.8 NominalT representation. 74

Figure : 6.9 Nominal representation. 74

Figure : 6.10 Long Transmission Line. 74

Figure : 7.1 Transformer. 93

Figure : 7.2 Three Phase Power Transformer 93

Figure : 7.3 Isolator 94

Figure : 7.4 Lightning arrestor 95

Figure : 7.5 Pin type insulator 96

Figure : 7.6 Suspension type insulator 96

Figure : 7.7 Strain insulator 97

Figure : 7.8 Single Bus bar 98


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Figure : 7.9 Single Bus bar system with Sectionalisation 99

Figure : 7.10 Basic operation of circuit breaker 100

Figure : 7.11 Oil Circuit Breaker 101

Figure : 7.12 Vacuum circuit break 102

Figure : 7.13 Sulphur Hexa Fluoride Circuit Breaker 103

Figure : 7.15 Single Line diagram of Bhurulia Sub-Station 106

Figure : 7.16 Power triangle 107

LIST OF TABLE

Table List Description Page No

3.5 Owner wise monthly Generation 45

3.5.1 Installed Capacity of BPDB Power Plants as on April 2014. 46

3.5.2 Power supply situation on 18thMarch 2014 (Monday) 47

3.5.3 Daily Generation Report 48

4.8.2 Transmission System Of Srilanka 56

6.9 230 KV Transmission Lines 79

6.10 132 KV Transmission Lines 80

6.10.1 Recent Completed Project for Transmission 81

6.10.2 Hasnabad & Tongi 230 kV and Kalyanpur 132 kV S/s

Construction (Hasnabad-Aminbazar-Tongi & Haripur-Me

82

6.10.3 Joydevpur-Kabirpur-Tangail 78 km 132 kV T/L & 3 S/s Extn.

Project (Joydebpur-Kabirpur-Tangail 132 kV

83

6.10.4 Ishurdi-Baghabari 54 km 230 kV T/L Construction (Ishurdi

Baghabari-Serajgonj-Bogra 230 kV T/L Project)

83

6.10.5 On Going Project for Transmission

400/230/132 Network Development project (Trance-2)

84

6.10.6 Goalpara-Bagerhat 132 kV Double Circuit Transmission Line 84

6.10.7 Meghnaghat-Aminbazar 400 kV Transmission Line (NG1) 84

6.10.8 Construction & Extension of Grid Substations including

transmission line facilities (Phase-1)

85

6.10.9 Aminbazar-Old Airport 230 kV Transmission Line and Associated

Substations

85


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6.10.10 Transmission Efficiency Improvement through Reactive Power Compensation at

Grid Substations and Reinforcement of Goalpara Substation

85

6.10.11 Siddhirganj-Maniknagar 230 kV Transmission Line 86

6.10.12 132 kV Grid Network Development Project in Eastern Region. 86

6.10.13 National Power Transmission Network Development Project 86

6.10.14 Barisal-Bhola-Burhanuddin 230 kV Transmission Line Project 87

6.10.15 Grid Interconnction between Bangladesh(Bheramara) and

India(Baharampur)

87

6.10.16 Two new 132/33 kV substations at Kulaura & Sherpur with

interconnecting line

87

6.10.17 Bibiyana-Kaliakoir 400 KV and Fenchuganj-Bibiyana 230KV

Transmission Line (NG2)

88

6.10.18 Haripur 360 MW Combined Cycle Power Plant and Associated

Substation (PGCB Part)

88

7.7 List of equipment of Bhurulia substation 104

7.8 Rating of different equipment used in bhurulia sub-station

Rating of Oil circuit breaker

104

7.9 Rating of SF6circuit breaker 105

7.10 Rating of Vacuumcircuit breaker 105

7.11 Rating of Transformer (T1) 105



7.18 Voltage Regulator(For each phase) 106

REFERENCES 109


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CHAPTER-1

INTRODUCTION

1.1 BACKGROUND

For growing development of a country, electricity has a vital role in all sectors. For the proper

utilization, is required to transmit and distribute the electrical power through proper way. During

the early years small local generating station supplied power to respective local loads. Each

generating station needed enough installed capacity to meet the local peak loads. Bangladesh is an

underdeveloped country. Its socio- economic structure is gradually increasing. So the demand of

power is extending day by day and thus the importance of Generation, Transmission and

Distribution are becoming more complicated.

An electric power system consist of the three principal components are the generation system,

transmission system and distribution system. The increasing uses of electric power for domestic,

commercial and industrial purposes necessities to provide bulk electric power economically. This

is achieved with the help of suitable power generating units, known as power plant. An electric

power station is an assembly of equipments in which energy is converted from one form to

another into electric energy. Electrical equipments of power station include generators,transformers, switch gears and control gears. The transmission lines are the connecting links

between the generating stations and the distribution system and lead to the power system over

interconnections. It is required to proper distribute the electric power to the consumer by a

network is called the distribution system.

1.2 OBJECTIVES OF THE THESIS

a) To study the different power stations such as hydro electric power station, thermal power

station, Nuclear power station, diesel power station and Gas turbine power station.

b) To study the comparative facilities of different power station.

c) To study the comparative productive ability of different power stations.

d) To study the power generation in Bangladesh.

e) To study the transmission system in Bangladesh.


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CHAPTER-2

OVERVIEW OF POWER GENERATION SYSTEMS

2.1 GENERATING STATION

Bulk electric power is produced by special plant is known as the generating station or power

plants. A generating station essentially employs a prime mover coupled to an alternator for the

production of electric power. The alternator converts mechanical energy of the prime mover into

electrical energy. The electrical energy produced by the generating station is transmitted and

distributed with the help of conductors of various consumers.

2.2 TYPES OF GENERATING STATION

1) Steam power plant

2) Hydro-electric power plant

3) Nuclear power plant

4) Diesel power plant

2.3 STEAM POWER PLANT

A generating station that converts the heat energy of coal combustion into electrical energy is

known as a steam power station.

2.3.1 CHOICE OF SITE FOR STEAM POWER STATIONS

1. Supply of fuel:The steam power station should be located near the coal mines so that

transportation cost is minimum. However, if such a plant is to be installed taken that

adequate facilities exists for the transportation of coal.

2. Availability of water:As huge amount water is required for the condenser therefore, such

a plant should be located at the bank of a river or near a canal to endure the continuous

supply of water.

3. Transportation facilities:A modern steam power station often requires the transportation

of material and machinery. Therefore, adequate transportation facilities must exist. The

plant should be well connected to others part of the country by the rail road etc.


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4. Cost and Type of Land:The steam power station should be located at a place where land

is cheap and further extension, if necessary is possible. More ever the bearing capacity of

the ground should be adequate so that heavy equipment could be installed.

5. Nearness to the Load Centre:In order to reduce the transmission cost the plant should be

located near the centre of load. This is particularly important if dc supply is adopted, this

factor becomes relatively less important with consequent reduced transmission cost. It

possible to install the plant away from the load centers provided other conditions are

favorable.

6. Distance from Populated Area:As huge amount of coal is burnt in a steam power

station, therefore smoke and fumes plant should be located at a considerable distance from

the populated areas.

2.3.2 ADVANTAGES OF STEAM POWER PLANT

a) The fuel is quite cheap

b) Less initial cost as compared to other generating stations

c) It can be installed at by place irrespective of the existence of coal. The coal can be

transported to the site of the plant by rail or road.

d) It required less space as compared to the hydro-electric power station.

e) The cost of generation is lesser than that of the diesel power station.

2.3.3 DISADVANTAGES OF STEAM POWER PLANT

a) It pollutes the atmosphere due to the production of large amount of smoke and fumes.

b) It costlier in running cost as compared to hydro-electric plant.

2.3.4 SCHEMATIC ARRANGEMENT OF STEAM POWER PLANT

Although steam power station simply involves the conversion of heat of coal combustion into

electrical energy, etc if embraces many arrangements for proper working and efficiency. The

schematic arrangement of a modern steam power station is shown in bellow. Where the whole

arrangement can be divided into the following stages for the sake of simplicity.


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Fig: 2.1 Schematic arrangement of a steam power station.

2.3.5 DISCRIPTION OF VARIOUS SECTION OF STEAM POWER PLANT

1. Coal and ash handling arrangement

2. Steam generating plant

3. Steam turbine

4. Alternator

5. Feed water

6. Cooling arrangement

Coal and ash handling plant:

The coal is transported to the power station by road or rail and is stored in the coal storage plant.

Storage of coal is primarily a matter of protection against shortages. From the coal storage plant

coal is delivered to the coal handling plat where it is pulverized combustion without using large

quantity of excess air. The pulverized coal is fed to the boiler by belt conveyors. The coal is burnt

in the boiler and the ash produced after the complete combustion of coal is removed to the ash

handling plant and then delivered to the ash storage plant for disposal. The removal of the ash

from the boiler furnace is necessary for proper burning of coal.


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It is worthwhile to give a passing reference to the amount of coal burnt and ash produced in a

modern thermal power station. A 100 MW station operating at 50% load factor may burn about

20000 tons of coal per month and ash produced may be to the tune of 10% to 15% of coal fired

i.e., 2000 to 3000 tons. In fact in thermal power station about 50% to 60% of the total operating

cost consists of a boiler for the production of steam and other auxiliary equipment for the

utilization of flue gases.

a) Boiler:The heat of combustion of coal in the boiler is utilized to convert water into steam at

high temperature and pressure. The flue gases the boilers makes their journey through super

heater economizer, air pre heater and are finally exhausted to atmosphere through the

chimney.

b)

Super heater:The steam produced in the boiler is wet and is passed through a super heater

where it is dried and superheated water by the flue gases on their way to chimney.

Superheating provides two principal benefits. Firstly the overall efficiency is increased.

Secondly too much condensation in the last stages of turbine is avoided the supper heated

steam turbine through the main valve.

c) Economizer: An economizer is essentially a feed water heater and derives heat from flue

gases for this purpose. The fed to the economizer before supplying to the boiler. The

economizer extracts a part of heat of flues gassed to increase the feed water temperature.d) Air pre-heater: An Air pre-heater increase the temperature of the air supplied from coal

burning by deriving heat from flue gases. Air is drown from the atmosphere by a forced

draught fan and is passed through air pre heater before supplying to the boiler furnace. The air

drowns from the atmosphere by a forced draught fan and is passed through air pre heater

before supplying to the boiler furnace. The pre heater extracts heat from flue gases and

increases the temperature of air used for coal combustion. The principal benefits of preheating

the air are increased thermal efficiency and increased steam capacity per square meter of

boiler surface.

e) Steam turbine: The dry and superheated steam from the super heater id fed to the steam

turbine through main valve. The heat energy of steam when passing over the blades of turbine

is converted into mechanical energy. After giving heat energy to the turbine the steam is

exhausted to the condenser which condenses the exhausted steam by means of cold water

circulation.


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f) Alternator: The Steam turbine is coupled to an alternator. the alternator converts mechanical

energy of turbine into electrical energy. The electrical output from the alternator is delivered

to the bus bars through transformer circuit breaker and insulators.

g) Feed water:The condensate from condenser is used as feed water to the boiler some water

may lost in the cycle which is made up from external source. The feed water on its way to the

boiler is heated by water heaters and economizer. This helps in raising the overall efficiency

of the plant.

h) Cooling arrangement: In order to improve the efficiency of the plant. The steam exhausted

from the turbine is condensed by means of a condenser.

2.3.6: TYPICAL STEAM POWER PLANT

Fig: 2.2 Steam power plant

1. Cooling tower 15. Air intake

2. Cooling water pump 16. Economizer

3. Transmission line (3-phase) 17. Air pre heater

4. Unit Transmission line (3-phase) 18. Precipitator Electric generator (3-phase)

19. Feed heater

5. Low pressure turbine 20. Coal conveyor

6. Condensate extractions pump 21. Coal hopper


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7. Condenser 22. Pulverized fuel mill

8. Intermediate pressure turbine 23. Boiler dr10Steam

9. Steam governor valve 24. Ash hopper

10. High pressure turbine 25. Induced draught fan

11. Deaerator 26. Chimney stack

12. Super heater

13. Re heater

2.3.6.1: Steam generator:

Schematic diagram of typical coal-fired power plant steam generator highlighting the air pre

heater (APH) location (For simplicity, any radiant section tubing is not shown)

Fig: 2.3 Steam generator

In fossil fueled power plants, steam generator refers to a furnace that burns the fossil fuel to boil

water to generate steam. In the nuclear plant field, steam generator refers to a specific type of

large heat exchanger used in a pressurized water reactor (PWR) to thermally connect the primary

and secondary systems, which of course is used to generate steam. In nuclear reactor called a

boiling water reactor (BWR), water is boiled to generate steam directly in the reactor itself and

there are no units called steam generators. In some industrial settings, there can also be steam-

producing heat exchangers called heat recovery steam generators which utilize heat from some

industrial process. The steam generating boiler has to produce steam at the high purity, pressure


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and temperature required or the steam turbine that drives the electrical generator. A fossil fuel

steam generator includes an economizer, a steam drum, and the furnace with its steam generating

tubes and super heater coils. Necessary safety valves are located at suitable points to avoid

excessive boiler pressure. The air and flue gas path equipment include forced draft fan, air pre

heater boiler furnace, fly ash collectors and the flue gas stack.

Geothermal plants need no boiler since they used naturally occurring steam source. Heat

exchangers may be used where the geothermal steam is very corrosive or contains excessive

suspended solids. Nuclear also boil water to raise steam, either directly generating steam from the

reactor (BWR) or else using an intermediate heat exchanger (PWR).

For units over about 200 MW capacity, redundancy of key components is provided by installing

duplicates of the FD fan, APH, fly ash collectors and ID fan with isolating dampers. On some

units of about 60 MW, tow boilers per uint may instead be provided.

2.3.6.2: Boiler furnace and steam drum:

Once water inside the boiler or steam generator, the process of adding the latent heat of

vaporization or enthalpy is underway. The boiler transfers energy to the water by the chemical

reaction of burning some type of fuel. The water enters the boiler through a section in the

convection pass called the economizer. From the economizer it passes to the steam drum. Once

the water enters the stream drum it goes down the down comers to the lower inlet water wall

headers. From the inlet headers the water rises through the water walls and is eventually turned

into steam and due to the heat being generated by the burners located on the front and rear water

walls. As the water is turned into steam in the water walls, the steam once again enters the steam

drum. The steam/vapor is passed through a series of the steam and water separators and then

dryers inside the steam drum . The steam separators and dryers remove water droplets from the

steam and the cycle through the water walls is repeated. This process is known as natural

circulation.

The boiler furnace auxiliary equipment includes coal feed nozzles and igniter guns, soot blowers,

water lancing and observation ports (in the furnace walls) for observation of the furnace interior.

Furnace explosions due to any accumulation of combustible gases after a trip-out are avoided by

flushing out such gases from the combustion zone before igniting the coal.

The steam drum (as well as the super heater coils and headers) have air vents and drains neededfor initial startup. The steam drum has internal devices that remove moisture from the wet steam


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entering the drum from the steam generating tubes. The dry steam then flows into the super heater

coils.

2.3.6.3: Super heater:

Fossil fuel power plants can have a super heater and/or re-heater section in the steam generating

furnace. Nuclear-powered steam plants do not have such sections but produce steam at essentially

saturated conditions. In a fossil fuel plant, after the steam is conditioned by the drying equipment

inside the steam drum, it is piped from the upper drum area into tubes inside an area of the

furnace known as the super-heater, which has an elaborate set up of tubing where the steam vapor

picks up more energy from hot flue gases outside the tubing and its temperature is now

superheated above the saturation temperature. The superheated steam is then piped through the

main steam lines to the valves before the high pressure turbine.

2.3.6.4: Re-heater:

Power plant furnaces may have a re-heater section containing tubes heated by hot flow gases

outside the tubes. Exhaust steam from the high pressure turbine is rerouted to go inside the re-

heater tubes to pickup more energy to go drive intermediate or lower pressure turbines. This is

what is called as thermal power.

2.3.6.5: Fuel preparation system:

In coal-fired power stations, the row feed coal from the coal storage area is first crushed into

small pieces and then conveyed to the coal feed hoppers at boilers. The coal is next pulverized

may be ball mills, rotating drum grinders, or other types of grinders. Some power station burn fuel

oil rather than coal. The oil must kept warm (above its pour point) in the fuel oil storage tanks to

prevent the oil from congealing and becoming unpumpable. The oil is usually heated to about

1000

c before being pimped through the furnace fuel oil spray nozzles.

Boilers in some power stations use processed natural gas as their main fuel. Other power stations

may use processed natural gas as auxiliary fuel in the event that their main fuel supply (coal or

oil) is interrupted. In such cases, separate gas burners are provided on the boiler furnaces.

2.3.6.6: Air path:

External fans are provided to give sufficient air for combustion. The forced draft fan takes air

from the atmosphere and first warming it in the air pre-heater for better combustion, injects it via


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the air nozzles on the furnace wall. The induced draft fan assists the FD fan by drawing out

combustible gases from the furnace, maintaining a slightly negative pressure in the furnace to

avoid backfiring through any opening.

2.3.6.7: Auxiliary Systems:

Fly ash collection: Fly ash is captured and removed from the flue gas by electrostatic

precipitators or fabric bag filters (or sometimes both) located at the outlet of the furnace and

before the induced draft fan. The fly ash is periodically removed from the collection hoppers

below the precipitators or bag filters. Generally, the fly ash is pneumatically transported to storage

silos for subsequent transport by trucks or railroad cars.

2.3.6.8 : Action and disposal:

Bottom ash collie: At the bottom of the furnace, there is a hopper for collection of bottom ash.

This hopper is always filled with water to quench the ash and clinkers falling down from the

furnace. Some arrangement is included to crush the clinkers and for conveying the crushed

clinkers and bottom ash to a storage site.

Boiler make-up water treatment plant and storage: Since there is continuous withdrawal of

steam and continuous return of condensate to the boiler, losses due to blow down and leakages

have to be made up to maintain a desired water level in the boiler steam drum. For this,

continuous make-up water is added to the boiler water system. Impurities in the raw water input to

the plant generally consist of calcium and magnesium salts which impart hardness to the water.

Hardness in the make-up water to the boiler will from deposits on the tube water surface which

will lead to overheating and failure of the tubes. Thus, the salts have to be removed from the

water, and that is done by water demineralising treatment plant (DM). A DM plant generally

consist of caution, anion, and mixed bed exchangers. Any ions in the final water from this processconsist essentially of hydrogen ions and hydroxide ions, which recombine to form pure water.

Very pure DM water becomes highly corrosive once it absorbs oxygen from the atmosphere

because of its very high affinity for oxygen.

The capacity of the DM plant is dictated by the type and quantity of salt s in the raw water input.

However, some storage is essential as the DM plant may be down for maintenance. For this

purpose, a storage tank is installed from which DM water is continuously withdrawn for boiler

make-up.the storage tank for DM water is made from materials not affected by corrosive water,


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such as PVC. The piping and valves are generally of stainless steel. Sometimes, a steam

blanketing arrangement or stainless steel doughnut float is provided on top of the water in the tank

to avoid contact with air.DM water make-up is generally added at the steam space of the surface

condenser (i.e., the vacuum side). This arrangement not only sprays the water but also DM water

gets deaerated, with the dissolved gases being removed by an air ejector attached to the condenser

2.3.6.9: Steam turbine-driven electric generator:Rotor of the modern steam turbine, used in a

power station.

Turbo generator:

Fig: 2.4 Turbo generator

The steam turbine-driven generators have auxiliary systems enabling them to work satisfactorily

and safely. The steam turbine generator being rotating equipment generally has a heavy, large

diameter shaft. The shaft therefore requires not only supports but also has to be kept in position

while running. To minimize the frictional resistance to the rotation, the shaft has a numbering of

bearings. The bearing shells, in which the shaft rotates, are lined with a low friction material like

Babbitt metal. Oil lubrication is provided to further reduce the friction between shaft and bearing

surface and to limit the heat generated.

2.3.6.10: Bearing gear:

Barring gear (or turning gear) is the mechanism provided to rotate the turbine the turbine

generator shaft at a very low speed after unit stoppages. Once the unit is tripped (i.e., the steam

inlet valve is closed), the turbine coasts down towards standstill. When it stops completely, there

is a tendency for the turbine shaft to deflect or bend if allowed to remain in one position too long.This is because the heat inside the turbine casing tends to concentrate in the top half of the casing,


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making the top half portion of the shaft hotter than the bottom half. The shaft therefore could

wrap or bend by millionths of inches.

This small shaft deflection, only detectable by eccentricity meters, would be enough to cause

damaging vibrations to the entire steam turbine generator unit when it is restarted. The shaft is

therefore automatically turned al low speed (about one percent rated speed) by the barring gear

until it has cooled sufficiently to permit a complete stop.

Condenser:

Fig: 2.5 Diagram of a typical water cooled surface condenser.

The surface condenser is a shell and tube heat exchanger in which cooling water is circulated

through the tubes. The exhaust steam from the low pressure turbine enters the shell where it is

cooled and converted to condensate (water) by flowing over the tubes as shown in the adjacent

diagram. Such condensers use steam ejectors or rotary motor-driven exhausters for continuous

removal of air and gases from the steam side to maintain vacuum. For best efficiency, the

temperature in the condenser must be kept as low as practical in order to achieve the lowest

possible pressure in the condensing steam. Since the condenser temperature can almost always be

kept significantly below 1000c where the vapor pressure of water is much less than atmospheric

pressure, the condenser generally works under vacuum. Thus leaks of non condensable air into the

closed loop must be prevented. Plants operating in hot climates may have to reduce output if their

source of condenser cooling water becomes warmer; unfortunately this usually coincides with

periods of high electrical demand for air conditioning. The condenser generally uses either


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circulating cooling water from a cooling tower to reject waste heat to the atmosphere or once-

through water from a river, lake or ocean

Feed water heater:

Fig: 2.6 A Ranking cycle with a two stage steam turbine and a single feed water heater.

In the case of a conventional steam-electric power plant utilizing a drum boiler, the surface

condenser removes the latent heat of vaporization from the steam as it changes states from vapor

to liquid. The heat content (btu) in the steam is referred to as Enthalpy. The condensate pump then

pumps the condensate water through a feed water heater The feed water heating equipment then

raises the temperature of the water by utilizing extraction steam from various stages of the

turbine, Preheating the feed water reduce the irreversibility involved in steam generation and

therefore improves the thermodynamic efficiency of the system,[9] This reduces plant operatingcost and also helps to avoid thermal shock to the boiler metal when the feed water is introduced

back into the steam cycle

2.3.6.11: Super heater:

As the steam is conditioned by the drying equipment inside the drum, it is piped from the upper

drum area into an elaborate set up of tubing different areas of the boiler. The areas known as super

heater and re-heater, the steam vapor picks up energy and its temperature is now superheated


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above the saturation temperature. The superheated steam is then piped through the main steam

lines to the valves of the high pressure turbine

Deaerator:

Fig: 2.7 Boiler feed water deaerator.

A steam generating boiler requires that the boiler feet water should be devoid of air and other

dissolved gases, particularly corrosive ones, in order to avoid corrosion of the metal. Generally,

power station use a deaerator to provide for the removal of air and other dissolved gases from the

boiler feed water. A deaerator typically includes a vertical, domed deaeration section mounted on

top of a horizontal cylindrical vessel which serves as the deaerated boiler feed water storage tank.

There are many different designs for a deaerator and the designs will vary from one manufacturer

to another. The adjacent diagram depicts a typical conventional traded deaerator. If operated

properly; most deaerator manufacturers will guarantee that oxygen in the deaerated water will not

exceed 7 ppb by weight (0.005 cm3

/L).

2.3.6.12: Auxiliary systems:

Oil system:An auxiliary oil system pump is used to supply oil at the start-up of the steam turbine

generator. It supplies the hydraulic oil system required for steam turbines main inlet steam stop

valve, the governing control valves, the bearing and seal oil systems, the relevant hydraulic relays

and other mechanisms. At a preset speed of the turbine during start-ups, a pump driven by the

turbine main shaft takes over the functions of the auxiliary system.


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Generatorheat dissipation:The electricity generator requires cooling to dissipate the heat that it

generators. While small units may be cooled by air drawn through filters at the inlet, lager units

generally require special cooling arrangements. Hydrogen gas cooling, in an oil sealed casing, is

used because it has the highest known heat transfer coefficient of any gas and for its low viscosity

which reduces winding losses. This system requires special handling during start up, with air in

the chamber first displaced by carbon dioxide before filing with hydrogen ensures that the highly

flammable hydrogen does not mix with oxygen in the air.

The hydrogen pressure inside the casing is maintained slightly higher than atmospheric pressure

to avoid outside air ingress. The hydrogen must be sealed against outward leakage where the shaft

emerges from the casing. Mechanical seals around the shaft are installed with a very small annular

gap to avoid rubbing between the shaft and the seals. Sal oil is used to prevent the hydrogen gas

leakage to atmosphere.

The generator also uses water cooling. Since the generator coils are at a potential of about 22 KV

and water is conductive, an insulting barrier such as Teflon is used to interconnect the water line

and the generator high voltage windings. Dematerialized water of low conductivity is used.

Generator high voltage system: The generator voltage ranges from 11 KV in smaller unit to 22

KV in larger units. The generator high voltage leads are normally large aluminum channelsbecause of their high current as compared to the cables used in smaller machines. They are

enclosed in well-grounded aluminum bus ducts and are supported on suitable insulators. The

generator high channels are connected to step-up transformers for connecting to a high voltage

electrical substation (of the order of 115 KV to 520 KV) for further transmission by the local

power grid. The necessary protection and metering devices are included for the high voltage

leads. Thus, the steam turbine generator and the transformer from one unit. In smaller units,

generating at 11 KV, a breaker is provided to connect it to a common 11 KV bus system

2.3.6.13: Other Systems:

Monitoring and alarm system: Most of the power plant operational control is automatic.

However, at times, manual intervention may be required. Thus, the plant is provided with

monitors and alarm systems that alert the plant operators when certain operating parameters are

seriously deviating from their normal range.

Battery supplied emergency lighting and communication: A central battery system consistingof lead acid cell units is provided to supply emergency electric power, when needed, to essential


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items such as the power plants control systems, communication systems, turbine lube oil pumps,

and emergency lighting. This is essential for a safe, damage-free shutdown of the units in an

emergency situation.

Transport of coal fuel to site and to storage: Most thermal stations use coal as the main fuel.

Raw coal is transported from coal mines to a power site by trucks, barges, bulk cargo ships or

railway cars. The coal received at site may be off different sizes. The railway cars are unloaded at

site by rotary dumpers or side till dumpers to tip over onto conveyors conveyor belt below. The

coal is generally conveyed to crush the coal to about inch (6mm) size. The crushed coal is then

sent by belt conveyors to a storage pile. Normally, the crushed coal is compacted by bulldozers, as

compacting of highly volatile coal avoids spontaneous ignition.

2.3.7 EFFICIENCY OF STEAM POWER PLANT

There are two types of efficiency in thermal power plant.

I) Thermal efficiency

II) Overall efficiency.

Thermal efficiency:

The ratio of heat equivalent of mechanical energy transmitted to the turbine shaft to the heat of

combustion of coal is known as Thermal efficiency of steam power station

2.4 HYDRO-ELECTRIC POWER STATION

A generating station which utilizes the potential energy of water at a high level for the generation

of electrical energy is known as hydro-electric power station


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Fig: 2.8 Schematic arrangement of a hydro-electric power station.

2.4.1 CHOICE OF SITE FOR HYDROELECTRIC POWER STATIONS

The following points should be taken into account whole selecting the site for a hydro electric

power station.

1. Availability of water: Such plants should be built at a place where adequate water is

available at a good head due to the primary requirement of a hydro-electric power station

is the availability of huge quantity of water.

2. Storage of water: There are wide variations in water supply from a river or canal during

the year. This makes it necessary to store water by constructing a dam. Site selection for a

hydro-electric power plant should be provides adequate facilities for erecting a dam and

storage of water.

3.

Cost and type of land: the land for the construction of the plant should be available at a

reasonable price. The bearing capacity of the ground should be adequate to withstand the

weight of heavy equipment to be installed.

4. Transportation facilities:the site selection for a hydro-electric plant should be accessible

by rail, river and road. So that necessary equipment and machinery could be easily

transported.

2.4.2 ADVANTAGES OF HYDRO-ELECTRIC POWER STATION

1. It is neat and clean as no smoke or ash is produced


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2. It has a longer life.

3. It required very small running charges because water is available free of cost.

4. As compare to steam power station, it does not require a long starting time.

5. Such plants serve many purposes. In additional to the generation of electrical energy,

they also help in irrigation and controlling flood.

6. No fuel is burnt.

2.4.3 DISADVANTAGE OF HYDRO-ELECTRIC POWER STATION

1. Capital cost is high as compare to other stations.

2. Skilled and experienced hands are required to build the plant.

3. Transmission cost is high as the plant is located in hilly areas which are quite away from

the consumers.

4. Uncertainty about the availability of huge amount of water due to dependence on

weather conditions.

2.4.4 CONSTITUENTS OF HYDRO-ELECTRIC PLANT:

a) Dam: A dam is a barrier, which stores water and creates water heads. Dams are building

of concrete or stone -masonry, earth or rock field. The type and arrangement depend

upon the topography of site. The type of dam also depends upon the type of foundation

conditions local materials and transportations available, occurrence of earthquakes and

other hazards.

b) Spillways: In order to discharge the surplus water the storage reservoir in to the river on

the down-steam side of the dam, spillways are used.

c)

Head work:The head works consists of diversion structures at the head of an intake.

The generally include booms and racks for the diverting floating debris, sluices for by

passing debris and sediments and valves for the controlling the follow of water to the

turbine.

d) Surge tank: A surge tank is a small reservoir or tank in which water level rises or falls

to reduce the pressures swings in the conduit. A surge tank is located near the beginning

of the conduit. When the load on the turbine decreases, then increases the water level of

the surge tank and reversal.

e)

Penstocks:Penstocks are conduits, which carry water to the turbines; they are generally

made of reinforced concrete or steel. Various devices such as automatic butterfly valve,


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air valve and surge tank are provided for the protection of penstocks. Automatic

butterfly valve shuts off water flow through the penstocks promptly if it raptures. Air

valve maintains the air.

1. For high head.

2. Reaction turbine- for low and medium head

f)

Electrical equipments: This includes alternators, transformers, circuit breaker and other

switching and protective devices.

2.5 NEUCLEAR POWER STATION

A generating station in which nuclear energy is converted into electrical energy is known as a

nuclear power station. In nuclear power station, heavy elements such as Uranium (U-235) or

thorium (Th-232) are subjected to nuclear fission in a special apparatus known as a reactor. The

energy thus related is utilized in raising steam at high temperature and pressure. The steam runs

the turbine which converts energy into mechanical energy. The turbine drives the alternator which

converts mechanical energy into electrical energy.

2.5.1 SELECTION OF SITE FOR NUCLEAR POWER STATION

1. Availability of water: as sufficient water is required for cooling purposes, therefore, the

plant side should be located where ample quantity of water is available, e.g., across a river

or by sea side

2. Disposal if water: the waste produce by the fission in a nuclear power station is generally

radioactive which must be disposed of properly to avoid health hazards. The waste should

either be buried in a deep trench or disposal off in sea quite away from the sea short.

Therefore, the site selected for such a plant should have adequate arrangement for the

disposal of radioactive waste

3.

Steam turbine: the steam produce in the heat exchange is led to steam turbine through a

valve. After doing a useful work in the turbine, the steam is exhausted to condenser. The

condenser condenses the steam which is fed to the heat exchanger through feed water

pump.

4. Alternator: The steam turbine drives the alternator which converts mechanical energy

into electrical energy. The output from the alternator is delivered to the bus-bares through

transformer, circuit breaker and isolators.


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2.5.2 ADVANTAGES OF NUCLEAR POWER STATION

1. The amount of fuel required is quite small. Therefore, there is a considerable saving in

the cost of fuel transportation?

2. A nuclear power plant requires less space as compared to any type of the same size.

3. It has low running charges as a small amount of fuel is used to producing bulk electrical

energy.

4. This type of plant is very economical for producing bulk electrical energy.

5. It can be located near the load centers because it does not require large quantities of

water and need not be near coal mines. Therefore, the cost of primary distribution is

reduced.

6. There are large deposits of nuclear fuels available all over the world .Therefore, such

plant can ensure continued supply of electrical energy for thousands of years.

7. It ensures reliability of operation.

2.5.3 DISADVANTAGES OF NUCLEAR POWER STATION

1. The fuel used is expensive and difficult to recover.

2. The capital cost on a nuclear plant is very high as compared to other types of plants.

3. The erection and commissioning of the plant requires greater technical knowhow.

4. The fission by products is generally radioactive and may cause a dangerous amount of

radioactive pollution.

5. Maintenance charges are high due to lack of standardization.

6. Nuclear plants are not well suited for varying loads as the reactor does not respond to the

load efficiently.

7. The disposal of the by products, which are radioactive, is big problem. They have either

to be disposed off in a deep trench or in a sea away from sea shore.

2.5.4 SCHEMATIC ARRANGEMENT OF NUCLEAR POWER STATION

The schematic arrangement of a nuclear power station is shown in fig. the whole arrangement can

be divided into the following main stages:

1. Nuclear reactor

2. Heat exchange

3. Steam turbine

4. Alternator


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Fig: 2.9 Schematic Arrangement of a Nuclear power Station.

Nuclear reactor:It is an apparatus in which nuclear fuel (U-235) is subjected to nuclear fission.

It control is the chain reaction that start once the fission is done. If the chain reaction is not

controlled, the result will be an explosion due to the fast increase in the energy released.

Chain reaction: nuclear fission is done by bombarding Uranium nuclei with slow moving

neutrons. This splits the Uranium nuclei with the release of huge amount of energy and emission

of neutrons. This fissions neutron cause further fission. If this process continues, then in a very

short time huge amount of energy will be released which may cause explosion. This is known as

explosive chain reaction. But in a reactor, controlled chain reaction is allowed. This is done by

systematically removing the fission neutrons from the reactor. The greater the number of fission

neutrons removes, the lesser is intensive of energy of released.

1. Heat exchanger: The coolant gives up heat exchanger which is utilized in raising

the steam. After giving up the heat, the coolant is again fed to the reactor.

2. Steam turbine:The steam produced in the heat exchanger led to the steam turbine

through a valve after doing useful work in the turbine, the steam is exhausted to

condenser. The condenser condenses the steam which is feed to the heat exchanger

through feed water pump

3. Alternator: The steam turbine drives the alternator which converts mechanical

energy into electrical. The output from the alternator is delivered to the bus-bars

through transformer, circuit breakers and isolators.


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2.6 DISEL POWER STATION

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.

2.6.1 CHOICE OF SITE FOR DIESEL POWER STATION

1. Distance from load center [the plant should be located nearby the load center to be

minimum transmission loss].

2. Availability of water.

3. Foundation condition. [A foundation at a reasonable depth should be capable of

providing a strong support to the engine].

4. Fuel transportation. [Plant should be near to the source of fuel supply so thattransportation charges are low].

5. Access to site. [The site selected should have road and rail transportation facilities].

2.6.2 ADVANTAGES OF DIESEL POWER STATION

a) It requires less space as compare to other stations.

b) The design and layout of this plant are very simple.

c)

For cooling system less quantity of water is required.d) It can be located at any place.

e) There are no standby losses.

f)It can be started quickly.

g) It requires less operating staff.

2.6.3 DISADVANTAGES OF DIESEL POWER STATION

a) This plant can generate small power.

b) The fuel cost is high.

c) This plant does not work for a longer period.

d) The cost of lubricating is high.

e) The maintenance charges are high.

f) It pollutes the atmosphere.

g) It makes a noise.


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2.6.4 SCHEMATIC ARRANGEMENT OF DIESEL POWER PLANT

Fig: Schematic diagram of a diesel power Station.

Fig: 2.10 Schematic Arrangement of a Diesel Power Plant

2.7 GAS TURBINE POWER STATION

A generating station which employs gas turbine as the prime mover for the generation of electrical

energy is known as a gas turbine power plant.

2.7.1 ADVANTAGES OF GAS TURBINE POWER STATION

a) It is simple in design.

b) It is much smaller in size.

c) Initial and operating costs are lower than other.

d) The maintenance charges are quite small.

e) There is no stand by losses.

2.7.2 DISADVANTAGES OF GAS TURBINE POWER STATION

a.There is a problem for starting the unit.

b. Since a greater part of power developed by the turbine is used in driving the

compressor, the net output is low

c.It pollutes the atmosphere.

d. The overall efficiency of such plants is low.


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2.7.3 SCHEMATIC ARRANGEMENT OF A GAS TURBINE POWER PLANT

Fig: 2.11 Schematic arrangement of a gas turbine power plant.

2.7.4 THE MAIN COMPONENT OF THE PLANTS

a)

Compressor: The compressor draws the air via the filter, which removes the dust from

air. The rotary blades of the compressor push the air between stationary blades to raise

its pressure. Thus air at high pressure is available at the output of the compressor.

b) Regenerator:A regenerator is a device, which recovers heat from the exits gases of the

turbine. A regenerator consists of nest of tubes contained in a shell. The compressed air

from the compressor passes through the tubes on its way to the combustion chamber. In

this way compressed air is heated by the exhaust gases.

c)

Combustion chamber: The air at high pressure from the compressor is led to thecombustion chamber via the regenerator. In the combustion chamber heat is added to the

air by burning oil/gas. The result is that the chamber attains a very high temperature. The

combustion gases are suitably cooled to 70000c-8000c and then delivered to the gas

turbine.

d) Gas turbine: The product of combustion comprising of a mixture of gases at high

temperature and pressure are passed to the gas turbine. These gases in passing over the

turbine blades expand and thus do the mechanical work. The temperature of the exhaustgases from the turbine is about 4800c


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e) Alternator: The gas turbine is coupled to the alternator. The alternator converts

mechanical energy of the turbine into electrical energy.

f)Starting Motor: Before starting the turbine, compressor has to be started. For this

purpose, an electrical motor is mounted on the same shaft of the turbine. This is

energized by the batteries. Once the unit starts, a part of mechanical power of the drives

the compressor and there is no need of motor now.


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CHAPTER-3

POWER GENERATION IN BANGLADESH

3.1 GENERATING VOLTAGE OF DIFFERENT POWER STATION

15.75kv

11kv

10.5kv

6.6kv

3.2 POWER DEMAND

The peak demand for January 2012 is 7,518 MW as per update power system master plan

(PSMP-2010). The maximum demand serves 5036.50 MW.

3.3 LOAD FACTOR AND LOAD MANAGEMENT

Consumer demand in BPDB system, as in any other electric utility varies throughout the day &

night. The maximum occurs during 5 PM to11 PM termed as peak hour. The extent of this

variation is measured in terms of load factor, which is the ratio of average & maximum demand,

for economic reason it is desirable to have a high load factor as this would permit better utilization

of plant capacity. The cost of energy supply during peak hour is high as some relatively costlier

power plants are required to be used during peak hour.

3.4 INSTALLED CAPACITY

Although the total installed capacity was 5493MW including 1330MW in IPP and 351MW in

internal power plant (Excluding REB).the maximum availability were

(1)Some plants were out of operation due to maintenance, rehabilitation &overhauling.

(2) Capacities of some plants were de-rated due to aging and Gas shortage.


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3.5Owner Wise Daily Generation:

Table : 01

Owner Name Derated Capacity (MW) Day Peak (MW) Eve. Peak (MW)

Generation of 21/04/2014

PDB 3502.00 1648.00 1972.00

SBU,PDB 223.00 194.00 201.00

EGCB 622.00 235.00 417.00

APSCL 682.00 468.00 465.00

IPP 1617.00 1165.00 877.00

SIPP,PDB 110.00 89.00 90.00

RENTAL(3 yrs) 33.00 0.00 0.00

SIPP,REB 215.00 160.00 175.00

Q.Rental 3 Years 100.00 95.00 100.00

QRPP(5yrs) 200.00 181.00 192.00

Other 825.00 650.00 581.00

RPP (3 Yrs.) 1069.00 740.00 780.00

QRPP (3 Yrs.) 416.00 335.00 380.00

RPP (15 Yrs.) 169.00 140.00 146.00

Total 9783.00 6100.00 6376.00


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3.5.1 Installed Capacity of BPDB Power Plants as on April 2014.

Capacity Type: Power Generation Units (Fuel Type Wise)

Installed Capacity of BPDB Power Plants as on April 2014

Unit Type Capacity(Unit) Total(%)

Coal 250.00 MW 2.44 %

FO 0.00 MW 0 %

Gas 6615.00 MW 64.59 %

HFO 1963.00 MW 19.17 %

HSD 683.00 MW 6.67 %

Hydro 230.00 MW 2.25 %

Imported 500.00 MW 4.88 %

Total 10241.00 MW 100 %

De rated Capacity of BPDB Power Plants as on April 2014

Unit Type Capacity(Unit) Total(%)

Coal 200.00 MW 2.04 %

FO 52.00 MW 0.53 %Gas 6224.00 MW 63.62 %

HFO 1926.00 MW 19.69 %

HSD 661.00 MW 6.76 %

Hydro 220.00 MW 2.25 %

Imported 500.00 MW 5.11 %

Total 9783.00 MW 100 %


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Daily Generation Report

Power Station NameDerated

Capacity(Unit)Day Peak Eve Peak

Daily Generation of 21/04/2014

a) Ghorasal ST 1, 2 78.00 MW 42.00 MW 45.00 MW

Ghorasal ST :Unit-3, 180.00 MW 100.00 MW 100.00 MW

Ghorashal ST 4 180.00 MW 170.00 MW 170.00 MW

Ghorashal 100 100.00 MW 84.00 MW 99.00 MW

Ghorrashal ST 5 190.00 MW 190.00 MW 190.00 MW

Ghorashal ST 6 190.00 MW 0.00 MW 0.00 MW

Ghorashal 45 MW 45.00 MW 43.00 MW 46.00 MW

Ghorashal MAX 78.00 MW 76.00 MW 78.00 MW

Ghorashal Regent 0.00 MW 2.00 MW 0.00 MW

Horipur SBU GT 1,2,3 60.00 MW 0.00 MW 0.00 MW

Horipur NEPC 110.00 MW 93.00 MW 110.00 MW

Horipur P. Ltd CCPP 360.00 MW 246.00 MW 325.00 MW

Meghnaghat P.Ltd CCPP 450.00 MW 440.00 MW 0.00 MW

Meghnaghat Summit 0.00 MW 0.00 MW 0.00 MW

Meghnaghat IEL 100.00 MW 91.00 MW 100.00 MW

Madanganj 102 MW 100.00 MW 95.00 MW 100.00 MW

Karanigonj 100.00 MW 90.00 MW 90.00 MW

Narshingdi 22.00 MW 16.00 MW 18.00 MW

Shiddirganj ST 150.00 MW 0.00 MW 0.00 MW

Siddirgonj GT 1,2 210.00 MW 0.00 MW 0.00 MW

Siddirgonj 100 MW 96.00 MW 56.00 MW 64.00 MW

Dutch Bangla 100 MW 100.00 MW 90.00 MW 92.00 MW

DPA Power 50 MW 50.00 MW 40.00 MW 46.00 MW

Gahamagar 0.00 MW 0.00 MW 0.00 MW

Horipur EGCB 360MW 412.00 MW 235.00 MW 417.00 MW

Summit Power (Dhaka) 146.00 MW 108.00 MW 116.00 MW


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Gazipur RPCL 52.00 MW 33.00 MW 32.00 MW

Tongi GT 105.00 MW 0.00 MW 0.00 MW

ChittagongRaozanST(Gas):Unit-1

180.00 MW 120.00 MW 120.00 MW

Raozan 25MW 25.00 MW 26.00 MW 26.00 MW

Patenga 50 MW 50.00 MW 3.00 MW 14.00 MW

ChittagongRaozanST(Gas):Unit-2

180.00 MW 0.00 MW 0.00 MW

Kaptai Hydro:Unit-1,2,3,4,5 220.00 MW 41.00 MW 106.00 MW

Shikalbaha ST 40.00 MW 0.00 MW 0.00 MW

b) Shikalbaha Peaking (GT) 150.00 MW 110.00 MW 120.00 MW

Hathazari 98.00 MW 23.00 MW 88.00 MW

Shikalbaha(Energis) 0.00 MW 0.00 MW 0.00 MW

Dohazari Sangu 102.00 MW 34.00 MW 51.00 MW

Julda 100.00 MW 80.00 MW 102.00 MW

Malancha, Ctg. EPZ(United)

0.00 MW 0.00 MW 23.00 MW

Barabkunda (Regent) 22.00 MW 17.00 MW 17.00 MW

a) Ashuganj ST Unit -1,2 110.00 MW 40.00 MW 40.00 MWb) Ashuganj ST 3 140.00 MW 140.00 MW 140.00 MW

Ashugonj ST 4 150.00 MW 140.00 MW 140.00 MW

Ashugonj ST 5 140.00 MW 80.00 MW 80.00 MW

c) Ashuganj CCPP-146MW 91.00 MW 40.00 MW 40.00 MW

d) Ashuganj 50 MW 51.00 MW 28.00 MW 25.00 MW

Ashuganj (Precision) 55.00 MW 51.00 MW 57.00 MW

Ashuganj (Aggreko) 80.00 MW 77.00 MW 82.00 MWAshugonj Up-53 MW 53.00 MW 53.00 MW 53.00 MW

Ashuganj Midland 51.00 MW 0.00 MW 0.00 MW

Brahmanbaria (Agrico)(Gas)

70.00 MW 70.00 MW 72.00 MW

Daudkandi 50 MW 52.00 MW 0.00 MW 49.00 MW

Chandpur CCPP 163.00 MW 155.00 MW 0.00 MW

Feni (Doreen) 22.00 MW 17.00 MW 18.00 MW

Feni, Mahipal (Doreen) 11.00 MW 8.00 MW 5.00 MW


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Jangalia (Summit) 33.00 MW 32.00 MW 32.00 MW

Summit Power, Comilla 25.00 MW 18.00 MW 21.00 MW

RPCL,CCPP, Mymensingh 197.00 MW 146.00 MW 145.00 MW

Tangail (Doreen) 22.00 MW 15.00 MW 18.00 MW

Fenchuganj CCPP-1 (Gas) 90.00 MW 66.00 MW 68.00 MW

Fenchuganj CCPP-2(New) 104.00 MW 84.00 MW 82.00 MW

Fenchuganj (BEDL) 51.00 MW 42.00 MW 42.00 MW

Fenchuganj Prima 50 MW 50.00 MW 46.00 MW 50.00 MW

Hobiganj (Confidence-EP) 11.00 MW 10.00 MW 10.00 MW

Shajibazar GT Unit-8, 9 66.00 MW 63.00 MW 68.00 MW

Shajibazar 86 MW 86.00 MW 74.00 MW 74.00 MW

Shajibazar - 50 MW 50.00 MW 45.00 MW 47.00 MW

Sylhet 150MW 142.00 MW 0.00 MW 108.00 MW

Sylhet GT (Gas) 20.00 MW 17.00 MW 19.00 MW

Sylhet 50 MW 50.00 MW 41.00 MW 44.00 MW

Sylhet 11 MW 10.00 MW 7.00 MW 9.00 MW

Shahjahanulla 25mw 25.00 MW 14.00 MW 24.00 MW

Bheramara GT (Unit-1,2,3) 46.00 MW 32.00 MW 32.00 MW

Bheramara 105.00 MW 0.00 MW 0.00 MW

a)Khulna ST 110 MW 55.00 MW 0.00 MW 58.00 MW

HVDC C/B. Interconnector 500.00 MW 403.00 MW 304.00 MW

b)Khulna ST 60MW 30.00 MW 0.00 MW 0.00 MW

KPC, Khulna 110.00 MW 53.00 MW 100.00 MW

KPCL Khulna (New) 115.00 MW 99.00 MW 99.00 MW

Khulna 150 MW 150.00 MW 156.00 MW 158.00 MW

Faridpur 54.00 MW 19.00 MW 45.00 MW

Gopalganj 110 MW 109.00 MW 0.00 MW 32.00 MW

Noapara (105MW)Quantam

101.00 MW 0.00 MW 0.00 MW

Noapara (40MW),KZA 40.00 MW 40.00 MW 40.00 MW

Khulna 40 MW 40.00 MW 0.00 MW 0.00 MW

Khulna 55 MW 55.00 MW 42.00 MW 53.00 MW

Barisal Diesel(HSD) 0.00 MW 0.00 MW 0.00 MW


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Barisal GT 1& 2 32.00 MW 15.00 MW 15.00 MW

Bhola Venture 33.00 MW 0.00 MW 0.00 MW

a)Baghabari GT 1 71.00 MW 67.00 MW 69.00 MW

b)Baghabari GT 2 100.00 MW 95.00 MW 100.00 MW

Baghabari 50 MW 52.00 MW 32.00 MW 32.00 MW

Baghabari Westmont 70.00 MW 0.00 MW 0.00 MW

Bera 70 MW 71.00 MW 67.00 MW 70.00 MW

Amnura 50 MW 50.00 MW 51.00 MW 50.00 MW

Khtakhali NPS 50MW 50.00 MW 50.00 MW 50.00 MW

Katakhali PPP 50 MW 50.00 MW 18.00 MW 46.00 MW

Sirajganj 150 MW 150.00 MW 75.00 MW 72.00 MW

Santahar 50MW 50.00 MW 46.00 MW 46.00 MW

Bogra GBB 22.00 MW 17.00 MW 21.00 MW

Rajlanka 52MW 52.00 MW 52.00 MW 52.00 MW

Barupukuria ST 1 100.00 MW 90.00 MW 90.00 MW

Barupukuria ST 2 100.00 MW 92.00 MW 93.00 MW

Bogra 20 MW 20.00 MW 9.00 MW 9.00 MW

Summit Powser(Ullapara) 11.00 MW 8.00 MW 10.00 MW

Rangpur GT (HSD) 20.00 MW 10.00 MW 17.00 MW

Syedpur GT 20MW(HSD) 20.00 MW 18.00 MW 18.00 MW

Thakurgaon 47 MW((RZ) 47.00 MW 31.00 MW 28.00 MW

Total 9783.00 MW 6100.00 MW 6376.00 MW


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CHAPTER 4

TRANSMISSION SYSTEM OF BANGLADESH

4.1 TRANSMISSION SYSTEM

The system by which the electrical power transmitted from generating station to distribution

system is known as transmission system. The transmission line divided in two parts:

1. Primary transmission

2. Secondary transmission

4.2 PRIMARY TRANSMISSION

The electric power at 132 KV is transmitted by 3-phase 3-wire over head system to the outskirts

of the city. This form is the primary transmission.

4.2.1 GRID SYSTEM

The entire AC network is interconnected network called national grid. Even neighboring national

grid are interconnected to from sub grid. In power system when all generating station line with the

operation of substation called grid system of electric power.

In the grid system of Bangladesh power development board, mainly two types of transmission

lines are used. These are 230KV and 132KV lines. Also there is another grid line of Bangladesh

i.e. 66KV.

4.2.2 GRID SUB-STATION

As in Bangladesh there are two types of grid transmission line, one 132KV line and other 230KV

line. So we have mainly two categories grid substation. The total number of grid substation

operated as of 2012 is 95, of which13 number are 230KV and 82 numbers are 132KV. Capacity

of 230KV grid substation is 6675MVA and 132KV is 8587MVA and their transmission length are

2647.3 circuit km and 6071.34 circuit km


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4.3 SECONDARY TRANSMISSION

The primary transmission line terminates at the receiving station which usually lies as the

outskirts of the city. At the receiving station, the voltages are reduced to 33KV by step down

transformers. From this station, electric power is transmitted at 33KV by three phase three wire

overhead system to various sub stations located at the strategic points in the city. This form is the

secondary transmission.

4.4 CLASSIFICATION OF OVERHEAD TRANSMISSION LINE

The overhead transmission lines are classified as

a) Short transmission line

b) Medium transmission line

c) Long transmission line

a) Short transmission line:When the length of an overhead transmission line is up to 50km and

the line voltage is comparatively high (20KV 100KV), it is usually considered as a Long

transmission line.

4.5 DEFINATION OF IMPORTANT TERMS:

1. Earthling or grounding: Connecting to earth or ground.

2. Neutral earthing: Connecting to earth, the neutral point i.e. the star point of generator,

transformer, rotating machine, neutral point of grounding transformer.

3. Reactance earthling: Connecting to the neutral point to earth through a reactance.

4. Resistance earthling: Connecting to the neutral point to earth through a resistance.

5. Non effecting earthling: when an intentional resistance or reactance is connected between

neutral point and earth.


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6. Solid earth or effective earth line: Connecting to the neutral point to earth without

intentional resistance or reactance co-efficient earthling.

7. Resonant earthing: Earthing through a reactance of such as value that power frequency

current in the neutral to ground connection almost equal opposite to power frequency

capacitance current between unsalted line and earth.

8. Co-efficient of ear thing: it is defined as the ratio of highest r.m.s voltage of healthy line to

earth to the line r.m.s voltage.

9. Petersen coil, suppression coil, ground fault neutralized: All the three terms have the same

meaning the adjustable reactor connected between neutral to earth.

10.Underground system: The system whose neutral point is not earth.

11.Earth fault factor: It is calculated at the selected point of the system for a given system. It

is a ratio of fault factor =V1/V2.

Where,

V1 = highest r.m.s phase to phase power frequency voltage of sound

phase during earth fault on another phase.

V2= r.m.s phase to phase power frequency voltage at the same

location with fault on the faulty removed.

12.Bus coupling transformer: it is a special kind of transformer using in electric power

transmission line. It is a bidirectional device that makes injection or taking electric power

between two buses. It is also a matching or interfacing transformer between two buses.

13. Bus: There are three kinds of buses in power system

a) PQ bus b) PV bus and c) Stack or swing or reference bus.

For studying and analyzing an electric bus, we have to need for important variables.They are:

a) P-active power b) Q-reactive power

c) V-voltage and d) -swing angle

4.6 ADVANTAGE OF HIGH VOLTAGE TRANSMISSION LINE

The transmission of electric power is carried at high voltage due to the following reason:

a) To reduce the volume of conductor material.


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b) To increase the transmission efficiency and

c) To decrease the percentage line drop

4.7 ADVANTAGES AND DISADVANTAGES OF HIGH VOLTAGE DC

TRANSMISSION

Advantages:

i. It requires only two conductors as compared to three for ac transmission.

ii. There is no inductance, capacitance, phase displacement and surge problem in dc

transmission.

iii. A dc transmission. Line has better voltage regulation as compared to the line for same load

and sending voltage.

iv. There is no skin effect in dc system.

v. A dc line requires less insulation as compared to ac line for the same working voltage.

vi. A dc line has less corona loss and interference with communication circuit.

vii. The high voltage dc transmission is free from the dielectric losses, particularly in the case

of cables and

viii. In dc transmission, there is no stability problem and synchronizing difficulties.

Disadvantages:

i. Electric power cannot be generated at high voltage dc due to commutation problems.

ii. The dc voltage cannot be stepped up for transmission of power at high voltages and

iii. The dc switches and circuit breaker have their own limitations.

4.8 TRANSMISSION SYSTEM OF DIFFERENT COUNTRIES

4.8.1 TRANSMISSION SYSTEM OF INDIA:

Bulk transmission system has increased to more than 165000 Circuit kmtoday. The entire country

has been divided into five regions for transmission systems. Namely:

1. Northern region

2. North Eastern region

3. Eastern region


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4. Southern region

5. Western region

Indias transmission system comprises a 400KV network as the main and bulk transmission

system at each region, 132KV and 110KV network as the main and support transmission systems

in each state, 66KV, 33KV and 22KV network as sub transmission system, frequent power cuts,

unscheduled shut downs and severe restrictions on industrial usage during summer months are

constraint on industrial development and overall economic development of the country. In this

context, POWERGRID is involved in along term plan for the development of an Indian national

transmission network to make efficient usage of generating capacity. As part of this strengthening

of the national grid, POWERGRID had developed series of high voltage direct current (HVDC)

inter regional links between North, East, South and westerns of Indias power system.

4.8.2 TRANSMISSION SYSTEM OF SRILANKA

Transmission voltage levels:

a) 220KV

b) 132KV

Transmission lines

220 KV----------------331km

132KV-----------------1684km

Grid substations NO. MVA

132/33KV 40 2570

220/132/33KV 6 2205

132/11KV 4 306

4.8.3 TRANSMISSION SYSTEM OF NEPAL

Nepal transmission voltage

Documents

STUDY OF ELECTRICAL POWER GENERATION,TRANSMISSION & DISTRIBUTION IN BANGLADESH