Electricity distribution network design 2nd E. Lakervi and E. J. Holmes Peter Peregrinus Ltd., on behalf of The Institution of Electrica! Engineers
Contents Pai> Preface and acknowledgements Preface to the 2nd edition xi xii 1 The supply System 1 1.1 Generation, transmission & distribution 1 1.2 Supply Organisation» 7 1.3 The distribution System 9 1.4 Supply requirements 12 1.5 Network configurations 13 1.6 Auxiliary Systems 17 2 Planning distribution networks 19 2.1 Overall philosophy 19 2.2 Planning objeetives 20 2.3 Combiniitg engineering and ecünomics 22 2.4 Eiltet of the existing network 22 2.5 Consideration of devclopmem trends 23 2.6 Produelion of long-term plans 24 2.7 Bibliography 25 3 Technical considerations 27 3.1 General 27 3.2 Modcliing network eoinponcnts 27 3.2.1 Coinponenti 27 3.2.2 Transforming impedanees 29 3.2.3 Per-unit values 30 3.3 Power flows and losses 32 3.3.1 Power llows 32 3.3.2 Power losses 33 3.3.3 Load and loss load factors 35 3.3.4 Heating eiltet 36 3.4 Voltage drop 38
Contents 3.5 System earlhing 3.5.1 General 3.5.2 Hazard voltages 3.5.3 Neutral earthing arrangements 3.5.4 Direct earthing 3.5.5 Impedance earthing 3.5.6 Arc-suppresiion-coil earthing 3.5.7 Isolated neutral Systems 3.5.8 Low-\ : oltage-sysu'm proteciive earlhing 3.6 Fault calculations 3.7 L'nsymmetrical faults 3.7.1 Sequence networks 3.7.2 System sequence impedanees 3.7.3 F.artli faults 3.8 Overvoltages 3.9 Bibliography Reliability 4.1 General 4.2 Reliability Investment appraisal 4.3 Basic reliability theoiy 4.3.1 Comporients 4.3.2 Radially operated Systems 4.3.3 Parallel or mesh Systems 4.4 Reliability calculation examplc 4.5 Bibliography Economic priilciples 5.1 Iniroduetion 5.2 I'resent worth 5.3 Discounled eash flow 5.4 Time seale of st.udies and residual valucs 5.5 Inflation and iiuercsi rates 5.6 Scnsitivttv analvsis 5.7 System losses 5.8 Other Factors 5.9 Bibliography Equipment 6.1 General 6.2 TransForrncrs 6.2.1 General 6.2.2 Losses 6.2.3 Insnlation life 6.2.4 Reaetanee of large supply transformers 6.2.5 UnsyrnnU'tiieal loads 6.3 Overhcad lines 6.4 Underground cables 6.5 Switchgear 6.5.1 Tntroduction 6.5.2 Circuit breakers 6.5.3 Disconucctors 6.6 ReplaccmenL oi equipment 6.7 Bibliography
Contents vu 7 System protection 124 7.1 General '24 7.2 Overcurrent protection 125 7.2.1 Ftises 12-1 7.2.2 Overcurrent relays 126 7.3 Earth-faull protection '29 7.4 Unit and dist.ariee protection 133 7.4.1 Unit protection 133 7.4.2 Distance protection 13 J 7.5 Autoredosing arrangement 136 7.6 Overvoltage protection 38 7.7 Automation of network Operation 40 7.8 Distribution managemenl Systems 141 7.9 Bibliograph) '"*J 8 HV networks and substations 148 0.1 General 1 1B 8.2 HV networks 148 8.3 Substation Arrangements läl 8.3.1 Site location 151 8.3.2 Design philosophy '^1 8.3.3 Mesh-typc substations 153 8.3.4 Single- and double-busbar arrangements 156 8.3.5 MV busbar arrangements 160 8.4 Auxiliary Systems 161 8.4.1 General 161 8.4.2 Transformer protection 162 8.4.3 Busbar protection 163 8.4.4 Auxiliary supplies 163 8.5 Bibliograph)' '6 ;i 9 MV networks 9.1 General 166 9.2 Choice of network voltage 167 9.3 System modelling 169 9.4 Principles for determining cireuit dimensions 1 / 9.4.1 Example: Choice of c:onductor size for a nevv line on an economic basis 172 9.4.2 Example: Choice of conductor size to replace an existing conductor ' ' + 9.5 Operational aspects 1^6 9.5.1 Network arrangements 176 9.5.2 Load-transfer schemes 1S3 9.5.3 Optimum location of protective equiprnenl and switching devices '85 9.5.4 Network reinforcements 18" 9.6 Bibliograph) 19 10 Distribution substations and LV networks 192 10.1 General 192 _ 10.2 Cable-connected substations 19-i 10.3 Pole-mounted substations 199 10.4 I.V nelwork arrangements '99 10.5 Service conneclions 205 10.6 Bibliograph) 208 166
viii Contents 11 Load data 11.1 Demands for dcsign 11.2 Load-monitoring measurcments 11.3 Load analysis and synthesis 1 1.4 Load foitcasting 11.5 Short-term load forecasts 11.6 Bibliography 12 Special loads 12.1 General 12.2 Electric-arc furtiaccs 12.2.1 I.oad cliaracteristics: 12.2.2 Voltage fluctuations and lamp Dicker 12.2.3 Melhods Tor rrducing voltage fluctuation 12.2.4 l.oading cycles and transformer losses 12.3 Convertors 12.4 Motors 12.4.1 Starting currenis 12.4.2 Voltage variations 12.4.3 Short-circuit contribution 12.4.4 Examplc of effeet of niotor loads on System 12.5 Raifway traction 12.6 Oüicr loads 12.6.1 Wclding cquipment 12.6.2 Induction heating equipment 12.6.3 Miscellaneous loads 12.7 Elcclromagnetir compatibility 12.7.1 Iiitcniatiotial regulations 12.7.2 Voltage characlcristics 12.7.3 Measurement of voltage cliaracteristics 12.8 Bibliograph) 13 Network voltage Performance 13.1 General 13.2 Voltage rcgulation 13.3 Automatic voltage control 13.4 Line-drop compensation 13.5 Distribution-translbrmer tap sellings 13.6 Regulators and capacitors 13.7 Integration of voltage-control facilities 13.8 Voltage unbalance 13.9 Constraints afferting network-voltage Performance 13.10 Guslomer-voltage fluctuations 13.11 Harmonics 13.12 Bibliography 14 Computer-based planning 14.1 General 14.2 Network Information Systems 14.2.1 General 14.2.2 Development phases 14.2.3 Information System eomponents 14.2.4 Network databases
14.2.5 Databasf maiiagemerit 14.2.6 Application programs 14.3 Xdwork calculations 14.4 Mathematical methods for network plannin 14.5 Examples of applicatums 14.5.1 Example 1 14.5.2 Example 2 14.6 Planning example 14.6.1 Data and targets 14.6.2 Present Situation 14.6.3 Demand forecasts 14.6.4 Development alternatives 14.6.5 Substation optimisation 14.7 Bibliograpliy 15 Co-operation in network planning and design 15.1 General 15.2 Town and eountry planning 15.3 Co-operation with otlicr organisations 15.4 Amenity malters 15.5 Mamifacturers and Consultants 15.6 Universities and rcseareh centres 15.7 Bibliograpliy Index