Transmission andDistribution of Power

Transmission and Distribution of Power

VIKAS® PUBLISHING HOUSE PVT LTD

K R SiddhapuraDeven B Raval

E-mail: helpline@vikaspublishing.com • Website: www.vikaspublishing.com

• Ahmedabad : 305, Grand Monarch, 100 ft Shyamal Road, Near Seema Hall, Ahmedabad-380051 • Ph. +91-79-65254204

• Bengaluru : First Floor, N S Bhawan, 4th Cross, 4th Main, Gandhi Nagar, Bengaluru-560009 • Ph. +91-80-22281254, 22204639

• Chennai : E-12, Nelson Chambers, 115, Nelson Manickam Road, Aminjikarai, Chennai-600029 • Ph. +91-44-23744547, 23746090 • Hyderabad : Aashray Mansion, Flat-G (G.F.), 3-6-361/8, Street No. 20, Himayath Nagar, Hydera-

bad-500029 • Ph. +91-40-23269992 • Fax. +91-40-23269993 • Kolkata : 6B, Rameshwar Shaw Road, Kolkata-700014 • Ph. +91-33-22897888 • Mumbai : 67/68, 3rd Floor, Aditya Industrial Estate, Chincholi Bunder, Behind

Balaji International School & Evershine Mall, Malad (West), Mumbai-400064 • Ph. +91-22-28772545, 28768301 • Patna : Flat No. 101, Sri Ram Tower, Beside Chiraiyatand Over Bridge, Kankarbagh Main Rd., Kankarbagh, Patna-800020 • Ph. +91-612-2351147

All rights reserved. No part of this publication which is material protected by this copyright notice may be reproduced or transmitted or utilized or stored in any form or by any means now known or hereinafter invented, electronic, digital or mechanical, including photocopying, scanning, recording or by any information storage or retrieval system, without prior written permission from the publisher.

Information contained in this book has been published by VIKAS® Publishing House Pvt Ltd and has been obtained by its Authors from sources believed to be reliable and are correct to the best of their knowledge. However, the Publisher and its Authors shall in no event be liable for any errors, omissions or damages arising out of use of this information and specifi cally disclaim any implied warranties or merchantability or fi tness for any particular use. Disputes if any are subject to Delhi Jurisdiction only.

Printed in India.

VIKAS® PUBLISHING HOUSE PVT LTDE-28, Sector-8, Noida-201301 (UP) India

Phone: +91-120-4078900 • Fax: +91-120-4078999

Registered Offi ce: 576, Masjid Road, Jangpura, New Delhi-110014. India

Transmission and Distribution of PowerISBN: 978-93259-8664-0

Vikas® is the registered trademark of Vikas Publishing House Pvt LtdCopyright © Authors, 2015

This book is dedicated to

The Goddess of knowledge, Maa Saraswati

and

Our loving uncle late Shri Dinesh D Raval (Dinesh Bapa), a famous Gujrati film director

K R SIDDHAPURA

D B RAVAL

Preface

The history of humankind is replete with remarkable discoveries and inventions. However, very few of these, like the use of fire, development of wheel and tapping of electricity, have changed the entire course of the life of man. Today, electricity is the most important factor in the development of any country, whether developing or developed. The demand for electrical power is increasing by leaps and bounds. Unfortunately, the generation of power is not keeping pace with the rising demand. The way out is either to augment capacity and generate more power or improve the efficiency of the existing electrical grid system. Since power generation is largely determined by economic consideration, government policy, local conditions and other such factors, the only alternative that remains is to improve the efficiency. Thus, full knowledge of design and operation of power generation, transmission and distribution of electric power is very essential for an electrical engineer.

This book provides that knowledge fully. It has been written strictly in accordance with the syllabus of West Bengal State Council of Technical Education. The language used is very simple and maintains a smooth flow. All the topics related to power systems have been covered with technically perfect diagrams, solved examples and various comparisons to prevent any confusion between two similar topics. Thus, it is truly student-friendly.

To improve the quality of the book further, suggestions from staff members and students are most welcome by us.

We are very thankful to our staff members for giving their guidance at every stage of the development of this book. We are also thankful to the entire team of Vikas Publishing House for their professional approach in publishing it.

K R SiddhapuraD B Raval

Syllabus

Contents (Theory) H/U M

1. Basics of Transmission 1.1 Layout of a Power System by single line concept. 1.2 Concept of Primary & Secondary transmission & distribution. 1.3 Advantages and limitations of using high voltage for power transmission. 1.4 Comparison between AC & DC power transmission systems. 1.5 Kelvin’s laws for the economic choice of conductor size — related problem.

04 4

2. Transmission Line Components 2.1 Main components of Overhead lines (names & functions only). 2.2 Types of conductors — Copper, Aluminum & state their trade names. 2.3 Solid, Stranded & bundled conductors. 2.4 Types of supports — RCC/PCC poles, steel tower. 2.5 Comparison between single circuit and double circuit design. 2.6 Conception of ground wire. 2.7 Line insulators — requirements, types, and field of applications. 2.8 Failure of insulators, creepage distance (definition & significance only). 2.9 Distribution of potential over a string of three suspension insulators. — Problems. 2.10 Concept of string efficiency, Methods of improving string efficiency.

— Problems. 2.11 Corona-corona formation, advantages & disadvantages, factors affecting corona,

important terms related to corona. 2.12 Calculation of Span length & sag. Calculation, effect of wind pressure, temperature

and ice deposition — Problems. 2.13 Stringing chart and its uses. 2.14 Spacing of conductors, length of span, Relevant I.E. Rules.

12 16

3. Tansmission Line Parameters: 3.1 R, L & C of 1-ph & 3-ph transmission line & their effects on line. (No deduction

and Problems) 3.2 Skin effect, proximity effect & Ferranti effect. 3.3 Concept of transposition of conductors & necessity.

3 3

Syllabusx

4. Underground Cables 4.1 Classification of cables and Comparison with overhead lines. 4.2 Cable construction. 4.3 Description of (i) PVC, (ii) PILC (iii) FRLS (Fire Retardant Low Smoke), (iv) XLPE

cables & (v) Gas filled (SF6) cables. 4.4 Cable Rating and De-rating factor. 4.5 Cable laying.

04 7

5. Performance of Transmission Line: 5.1 Classification of transmission lines. 5.2 Losses, Efficiency & Regulation of line. 5.3 Performance of single phase short transmission line (Numerical based on it). 5.4 Effect of load power factor on performance. Power Factor Improvement Using Static condenser and Synchronous condenser —

related problems. 5.5 Medium transmission lines — End condenser, Nominal T & Nominal Pi Network with

vector diagram. — no problem.

09 15

6. Extra High Voltage Transmission 6.1 EHVAC Transmission, Reasons for adoption & limitations. 6.2 Regional Grid System (Conception only). 6.3 Concept about FACTS and its applications. 6.4 HVDC Transmission — Advantages, Limitations. 6.5 Discussion on a few HVDC systems in Indian scenario.

03 5

7. Components of Distribution System: 7.1 Introduction. 7.2 Classification of distribution system. 7.3 AC distribution. 7.4 Connection schemes of the distribution system. 7.5 Requirements of distribution systems. 7.6 Design consideration. 7.7 AC distribution calculations. 7.8 Methods of solving AC-1 phase & 3 Ø-phase connection (balanced) distribution system.

(Numericals based on 1-ph & 3-ph balanced distribution system)

08 12

8. Substations 8.1 Introduction. 8.2 Classification of indoor & outdoor substations. 8.3 Advantages & Disadvantages. 8.4 Selection & location of site. 8.5 Main connection schemes. 8.6 Equipments and circuit element of substations — their symbols & functions. 8.6.1 Bus bar’s material, types in detail. 8.6.2 Connection diagram and layout of substations with proper notation.

05 8

Contents

Preface viiSyllabus ix

1. Basics of the Power System 1 Introduction 1 1.1 Layout of a Power System by Single-Line Concept 2 1.2 Concepts of the Primary and Secondary Transmission

and Distribution Systems 2 Generating Station 3; Primary Transmission 3; Secondary Transmission 3; Primary Distribution 3; Secondary Distribution 3

1.3 Advantages and Limitations of using High Voltage forPower Transmission 4

1.3.1 Various Systems Used for Power Transmission 4

1.4 Comparison between AC and DC Power Transmission Systems 5 1.5 Kelvin’s Law for the Economic Choice of Conductor Size 7 Graphical Illustration of the Kelvin’s Law 8; Limitations of the Kelvin’s Law 8 • Key Points to Remember 15 • Review Questions 16 • Numerical Problems 16

2. Transmission Line Components 18 Introduction 18 2.1 Main Components of Overhead Lines 19 2.2 Various Conductors Used in Transmission 20 2.2.1 Copper Conductor 20; 2.2.2 Aluminium Conductor 20; 2.2.3 Aluminium Conductor Steel Reinforced (ACSR) 21; 2.2.4 Cadmium Copper 21; 2.2.5 Galvanized Steel 21

2.3 Types of Conductor 21 2.4 Line Supports 22 2.5 Comparison between Single and Double Circuit Designs 27 2.6 Conception of Ground Wire 28 2.7 Line Insulators 28 2.7.1 Application of the Insulator 32

2.8 Failure of Insulators 32 2.8.1 Testing of Insulators 33

Contentsxii

2.9 Distribution of Potential Over a String of Three Suspension Insulators 33 2.10 String Efficiency 35 2.10.1 Methods of Improving String Efficiency 37

2.11 Corona 45 2.11.1 Formation of Corona 45; 2.11.2 Advantages of Corona 46; 2.11.3 Disadvantages of Corona 46; 2.11.4 Factors Affecting Corona 46; 2.11.5 Important Terms Related with Corona 47; 2.11.6 Methods or Reducing the Corona 48

2.12 Span Length 49 2.12.1 Sag and Tension 49; 2.12.2 Calculation of Sag 50; 2.12.3 Effect of Ice Coating on Sag 52; 2.12.4 Effect of Wind Pressure 53; 2.12.5 Combined Effect of Wind and Ice Coating 54; 2.12.6 Safety Factor 55

2.13 Stringing Chart and Its Uses 61 2.13.1 Sag Template 62

2.14 Spacing of Conductors 62 2.14.1 Span Length 62; 2.14.2 Indian Electricity Rules (1956) 62 • Key Points to Remember 66 • Review Questions 70 • Numerical Problems 71

3. Transmission Line Parameters 73 Introduction 73 3.1 Transmission Line Parameters 73 3.1.1 Resistance 74; 3.1.2 Inductance 75; 3.1.3 Capacitance 76; 3.1.4 Calculation of Inductance of a Line 76; 3.1.5 Inductance of a Single-Phase Two-Wire Line 81; 3.1.6 Inductance of a Three-Phase Line 82; 3.1.7 Inductance of a Double Circuit Transmission Line 85; 3.1.8 Potential Difference between Two Points Due to a Charge 89; 3.1.9 Capacitance of a Single-Phase Two-Wire Line 90; 3.1.10 Potential Difference between Two Conductors in a Group of

Charged Conductors 91; 3.1.11 Capacitance of a Three-Phase Line 91

3.2 Skin Effect 95 3.2.1 Proximity Effect 96; 3.2.2 Ferranti Effect 97

3.3 Concept of Transposition of Conductors and Necessity 97 • Key Points to Remember 98 • Review Questions 99 • Numerical Problems 99

4. Underground Cables 101 Introduction 101 4.1 Classification of Cables 101 4.1.1 According to the Type of Insulating Material 102; 4.1.2 According to the Voltage Level 102; 4.1.3 According to the Number of Cores used in the Cable 102; 4.1.4 According to the Construction of Cables 102; 4.1.5 According to the Sheath used in the Cable 102; 4.1.6 According to Armouring 103; 4.1.7 According to Application 103;

xiiiContents

4.1.8 According to Location 103; 4.1.9 Comparison between Cablesand Overhead Lines 103

4.2 Cable Construction 104 4.2.1 Cores or Conductors 104; 4.2.2 Insulation 105; 4.2.3 Metallic Sheath 105; 4.2.4 Bedding 105; 4.2.5 Armouring 106; 4.2.6 Serving 106

4.3 Different Types of Cables 106 4.3.1 Polyvinyl Chloride Cable (PVC) 106; 4.3.2 Paper-Insulated Lead-Covered (PILC)

Cable 107; 4.3.3 Fire-Retardant Low-Smoke (FRLS) Cable 108; 4.3.4 Cross-Linked Polythene (XLPE) Cable 109; 4.3.5 Gas-Filled (SF6) Cable 109

4.4 Cable Rating 110 4.4.1 Derating Factor of a Cable 111

4.5 Methods of Cable Laying 112 4.5.1 Direct Laying Method 112; 4.5.2 Draw-in System 112; 4.5.3 Solid System 113; 4.5.4 Cable Laying by Racking on Wall or

Overhead Structure 114; 4.5.5 Cable Laying by Racking in Tunnel 115 • Key Points to Remember 115 • Review Questions 116

5. Performance of Transmission Lines 118 Introduction 118 5.1 Classification of Transmission Lines 119 5.2 Voltage Regulation, Efficiency and Losses of Transmission Lines 119 5.3 Performance of a Single-Phase Short Transmission Line 120 5.3.1 Three-Phase Short Transmission Line 122;

5.4 Effect of Load Power Factor on the Performance of a Line 128 5.4.1 Power Factor Concept 129; 5.4.2 Disadvantages of Low Power Factor 131; 5.4.3 Causes of Low Power Factor 131; 5.4.4 Power Factor Improvement 132; 5.4.5 Power Factor Improvement by Static Capacitor 134; 5.4.6 Power Factor Improvement by Synchronous Condenser 135; 5.4.7 Power Factor Improvement by Phase Advancer 136

5.5 Medium Transmission Lines 144 5.5.1 End-Condenser Method 144; 5.5.2 Nominal T-Method 146; 5.5.3 Nominal p-Method 147

5.6 Compensation of Transmission Lines 149 • Key Points to Remember 149 • Review Questions 151 • Numerical Problems 152

6. Extra High Voltage Transmission 154 Introduction 154 6.1 Extra High Voltage (EHV) Transmission 154 6.1.1 Reasons to Adopt EHV (Advantages of EHV) 155; 6.1.2 Limitations of EHV 156

6.2 Regional Grid System 157 6.3 Flexible AC Transmission System (FACTS) 158 6.3.1 Advantages of FACTS 158; 6.3.2 Basic Types of ‘FACTS’ Controller 159; 6.3.3 Application of FACTS 161

6.4 HVDC Transmission 162

Contentsxiv

6.4.1 Working Principle of HVDC 162; 6.4.2 Advantages of HVDC System 163; 6.4.3 Limitations of HVDC 165; 6.4.4 Comparison between HVDC and EHVAC

Transmission Systems 165; 6.4.5 Types of HVDC Transmission System (LINK) 167; 6.4.6 Equipment Used in HVDC Transmission System 170

6.5 HVDC System in India 170 6.5.1 Various Challenges in the Development of HVDC 171; 6.5.2 Scope of HVDC

in India 171 • Key Points to Remember 172 • Review Questions 175

7. Components of the Distribution System 176 Introduction 176 7.1 Classification of the Distribution System 177 7.2 AC Distribution 179 7.3 Connection Schemes of the Distribution System 180 7.4 Requirement of the Distribution System 183 7.5 Design Consideration in the Distribution System 183 7.6 AC Distribution System Calculations 184 7.7 Methods for Solving Single-Phase and Three-Phase

AC Distribution Systems 184 • Key Points to Remember 195 • Review Questions 196 • Numerical Problems 197

8. Substations 198 Introduction 198 8.1 Classification of Substations 199 8.2 Advantages and Disadvantages of Outdoor Substation Over

Indoor Substation 200 8.2.1 Comparison between Outdoor and Indoor Substations 200

8.3 Selection and Location of Substations 201 8.4 Main Connection Schemes 202 8.4.1 Transformer Substation 202; 8.4.2 Pole-Mounted Substation 203; 8.4.3 Underground Substation 204; 8.4.4 Terminal and Through Substations 204; 8.4.5 Layout of a Substation 205

8.5 Equipment and Circuit Elements of a Substation 206 8.5.1 Symbols Used for Substation Equipment 208; 8.5.2 Bus Bar 209

8.6 Key Diagrams of Some Important Substations 216 • Key Points to Remember 221 • Review Questions 223

Transmission And Distribution OfPower

Publisher : SChand Publications ISBN : 9789325986640Author : K R Siddhapura,Deven B Raval

Type the URL : http://www.kopykitab.com/product/11728

Get this eBook

20%OFF