Electrical distribution engineering: 3rd

Preface ................................................................................................................xi History and Development ...........................................................................xiii PART ONE THE DISTRIBUTION SYSTEM ......................................... 1 1 The Distribution System: Description ........................................ 3 2 Distribution System Considerations ........................................... 9 Desired Features .................................................................................. 9 Types of Electric Systems .................................................................. 10 Types of Delivery Systems ................................................................ 21 Overhead versus Underground ......................................................... 32 PART TWO PLANNING AND DESIGN ............................................ 35 3 Load Characteristics ...................................................................... 37 Connected Loads ................................................................................ 37 Consumer Factors .............................................................................. 43 Consumer Classification .................................................................... 46 Fluctuation in Demand ..................................................................... 47 Future Requirements ......................................................................... 48 Voltage Requirements ........................................................................ 49 Service Reliability .............................................................................. 50 4 Electrical Design ............................................................................ 53 Services ............................................................................................... 53 The Secondary System ....................................................................... 54 The Primary System .......................................................................... 63 Voltage Regulators ............................................................................. 73 Taps .................................................................................................... 76 Boosters .............................................................................................. 76 Capacitors ........................................................................................... 77 Reactors .............................................................................................. 80 Transformers ...................................................................................... 81 Substations ......................................................................................... 94 Protective Devices ............................................................................ 100 Fault-Current Calculation ............................................................... 119 vi Street Lighting ................................................................................. 129 Practical Basis of Design ................................................................. 133 5 Mechanical Design: Overhead .................................................. 145 Criteria ............................................................................................. 145 Poles ................................................................................................. 146 Cross Arms ...................................................................................... 157 Pins .................................................................................................. 163 Secondary Racks .............................................................................. 166 Insulators ......................................................................................... 167 Guys and Anchors ........................................................................... 170 Conductors ....................................................................................... 178 Grades of Construction ................................................................... 184 Clearances ........................................................................................ 185 Joint Construction ........................................................................... 188 Practical Design Methods ............................................................... 190 Appendix 5 A Practical Method of Calculating Pole and Guy Sizes ............................................ 203 Introduction ........................................................... 203 Pole Class Requirements ....................................... 204 Guying Requirements ........................................... 213 Appendix 5B Examples .............................................................. 221 Appendix 5C Concrete and Metal Poles ................................. 224 Introduction ........................................................... 224 Construction .......................................................... 225 Installation ............................................................. 226 Design .................................................................... 226 6 Mechanical Design: Underground ........................................... 229 High-Density Loads: City and Downtown Areas .......................... 229 Practical Manhole Design Procedure ............................................. 242 Design Loading ................................................................................ 242 Design Stress Bases ......................................................................... 245 Wall Design ..................................................................................... 246 Roof Design ...................................................................................... 250 Floor Design .................................................................................... 252 Reinforcing Specifications ............................................................... 253 Gratings ........................................................................................... 253 Construction Practices .................................................................... 254 vii Reinforced Concrete Design ............................................................ 255 Sample Design Problem .................................................................. 259 Underground Residential Distribution (URD) .............................. 268 Design of Direct-buried Electrical Distribution Systems .............. 275 Appendix 6A Technical Reference Data .................................. 285 Use of Load-Estimating Curves for Residential Loads Including Space Heating ......... 285 Use of the URD-Loop Primary Conductor Size-Selector Chart ............................. 288 7 Distribution Substations ............................................................ 291 Site Selection .................................................................................... 291 General Design Features ................................................................. 292 Substation Construction .................................................................. 297 One-Line Diagrams of Connections ............................................... 299 8 Metering ......................................................................................... 301 Scope ................................................................................................. 301 Operation-Monitoring Meters ........................................................ 301 Revenue Metering ........................................................................... 303 Wiring Diagrams ............................................................................. 307 Electronic Metering ......................................................................... 307 Transducers ...................................................................................... 309 PART THREE MATERIALS AND EQUIPMENT ............................. 311 9 Conductors ..................................................................................... 313 Introduction ..................................................................................... 313 Materials .......................................................................................... 313 Cables ............................................................................................... 321 Secondary Mains ............................................................................. 322 Service Conductors .......................................................................... 323 Connections ...................................................................................... 323 Overhead-to-underground Connection ........................................... 326 Ties ................................................................................................... 326 Electrical Characteristics ................................................................. 328 10 Poles, Cross Arms, Pins, Racks, and Insulators .................... 331 Wood Poles ....................................................................................... 331 Concrete and Metal Poles ................................................................ 337 viii Concrete Poles .................................................................................. 337 Metal Poles ...................................................................................... 338 Cross Arms ...................................................................................... 339 Pins .................................................................................................. 340 Racks ................................................................................................ 342 Insulators ......................................................................................... 343 Test Voltages .................................................................................... 358 Appendix 10A Concrete Distribution Poles: Representative Specifications ...................... 359 Scope ................................................................. 359 Shape ................................................................. 359 Dimensions and Strength ................................ 360 Colors and Finishes .......................................... 360 Materials ........................................................... 363 General Requirements ...................................... 364 Manufacture ..................................................... 369 11 Transformers, Cutouts, and Surge Arresters .......................... 373 Transformers .................................................................................... 373 Distribution Transformers ............................................................... 375 Fuse Cutouts .................................................................................... 382 Surge Arresters ................................................................................ 386 12 Regulators, Capacitors, Switches, and Reclosers .................. 389 Voltage Regulators ........................................................................... 389 Capacitors ......................................................................................... 392 Switches ........................................................................................... 395 Circuit Breakers ............................................................................... 396 Reclosers ........................................................................................... 398 13 Distribution Substation Equipment ........................................ 399 Equipment ........................................................................................ 399 Transformers .................................................................................... 399 Circuit Breakers and Protective Relaying ....................................... 403 Fuses ................................................................................................. 404 Disconnect and Air-Break Switches ............................................... 405 Surge or Lightning Arresters .......................................................... 406 Voltage Regulators ........................................................................... 407 Storage Batteries .............................................................................. 408 ix Measuring Instruments ................................................................... 408 Capacitors and Street Lighting Equipment .................................... 409 Buses and Bus Supports .................................................................. 410 All Substation Equipment ............................................................... 410 PART FOUR U.S. ENERGY POLICY ACT OF 2005 ......................... 411 14 U.S. Energy Policy Act of 2005 ................................................. 413 Preface .............................................................................................. 413 Wind Power ..................................................................................... 413 Solar Power ...................................................................................... 416 Other “Green” Fuels ....................................................................... 418 Conservation .................................................................................... 419 Storage ............................................................................................. 419 The Primary Circuit ........................................................................ 419 PART FIVE OTHER DESIGN CONSIDERATIONS ...................... 421 15 Nontechnical Considerations .................................................... 423 Introduction ..................................................................................... 423 Safety ................................................................................................ 423 Quality of Service ............................................................................ 426 Economy ........................................................................................... 427 Conclusion ....................................................................................... 429 16 Operating Considerations .......................................................... 431 Introduction ..................................................................................... 431 Quality of Service ............................................................................ 431 Load Shedding .................................................................................. 432 Cogeneration and Distributed Generation ..................................... 435 Metering ........................................................................................... 439 Remote Meter Reading and Demand Control ................................ 441 Transformer Load Monitoring ......................................................... 441 Power Factor Correction ................................................................. 442 Demand Control .............................................................................. 442 Demand Control (or Peak Suppression) ......................................... 443 Conclusion ....................................................................................... 449 APPENDIXES ................................................................................................ 451 Appendix A Circuit Analysis Methods ................................................. 453 Introduction ............................................................................................ 453 x Circuit Transformations .......................................................................... 454 Superposition Theorem ........................................................................... 455 Symmetrical Components ....................................................................... 456 Sequence Filters ...................................................................................... 462 Appendix B Economic Studies ................................................................ 475 Introduction ............................................................................................ 475 Annual Charges ...................................................................................... 476 Broad Annual Charge ............................................................................. 484 Time Value of Money .............................................................................. 484 Examples ................................................................................................. 485 Procedure for Economic Studies ............................................................. 491 Conclusion ............................................................................................... 493 Appendix C The Grid Coordinate System: Tying Maps to Computers ................................................................ 495 Introduction ............................................................................................ 495 Grid Coordinate Maps ............................................................................ 498 Coordinate Data Handling ..................................................................... 502 Other Applications .................................................................................. 504 Economics ................................................................................................ 505 Appendix D Automated Distribution Comes of Age ........................ 507 Introduction ............................................................................................ 507 Bridging the Islands of Communication ................................................ 508 Single Functions Now Justify Installation ............................................ 508 Simulating an Operator’s Decisions ...................................................... 509 Load Management Tool ........................................................................... 510 Automated Distribution Features .......................................................... 513 Installing an Automated Distribution System ...................................... 514 Conclusion ............................................................................................... 514 Appendix E U.S. and Metric Relationships Index ............................. 517 Index ................................................................................................................ 519