Chapter 1. Power Delivery System Control and Automation ......... 1
1.1 Introduction ............................................... 1
1.2 Why Distribution Automation? ............................... 1
1.2.1 Incremental Implementation .......................... 4
1.2.2 Acceptance of DA by the Utility Industry ............ 5
1.3 Power Delivery Systems ..................................... 7
1.4 Control Hierarchy .......................................... 9
1.5 What Is Distribution Automation? .......................... 11
1.5.1 DA Concept ......................................... 11
1.6 Distribution Automation System ............................ 13
1.7 Basic Architectures and Implementation Strategies for
DA ........................................................ 17
1.7.1 Architecture ....................................... 17
1.7.2 Creating the DA Solution ........................... 19
1.7.3 Distribution Network Structure ..................... 21
1.8 Definitions of Automated Device Preparedness .............. 22
1.9 Summary ................................................... 23
References ..................................................... 25
Chapter 2. Central Control and Management ...................... 27
2.1 Introduction .............................................. 27
2.1.1 Why Power System Control? .......................... 27
2.2 Power System Operation .................................... 28
2.3 Operations Environment of Distribution Networks ........... 29
2.4 Evolution of Distribution Management Systems .............. 31
2.5 Basic Distribution Management System Functions ............ 35
2.6 Basis of a Real-Time Control System (SCADA) ............... 39
2.6.1 Data Acquisition ................................... 39
2.6.2 Monitoring and Event Processing .................... 41
2.6.3 Control Functions .................................. 44
2.6.4 Data Storage, Archiving, and Analysis .............. 44
2.6.5 Hardware System Configurations ..................... 45
2.6.6 SCADA System Principles ............................ 47
2.6.7 Polling Principles ................................. 48
2.7 Outage Management ......................................... 50
2.7.1 Trouble Call-Based Outage Management ............... 52
2.7.2 Advanced Application-Based Outage Management ....... 57
2.7.3 GIS-Centric versus SCADA-Centric ................... 60
2.8 Decision Support Applications ............................. 60
2.8.1 Operator Load Flow ................................. 61
2.8.2 Fault Calculation .................................. 63
2.8.3 Loss Minimization .................................. 66
2.8.4 VAR Control ........................................ 66
2.8.5 Volt Control ....................................... 67
2.8.6 Data Dependency .................................... 68
2.9 Subsystems ................................................ 69
2.9.1 Substation Automation .............................. 69
2.9.2 Substation Local Automation ........................ 72
2.10 Extended Control Feeder Automation ........................ 77
2.11 Performance Measures and Response Times ................... 79
2.11.1 Scenario Definitions ............................... 79
2.11.2 Calculation of DA Response Times ................... 81
2.11.3 Response Times ..................................... 85
2.12 Database Structures and Interfaces ........................ 86
2.12.1 Network Data Model Representations ................. 86
2.12.2 SCADA Data Models .................................. 87
2.12.3 DMS Data Needs, Sources, and Interfaces ............ 89
2.12.4 Data Model Standards (CIM) ......................... 93
2.12.5 Data Interface Standards .......................... 100
2.13 Summary .................................................. 100
Appendix 2A. Sample Comprehensive CIM Structure ............... 103
References .................................................... 104
Chapter 3. Design, Construction, and Operation of
Distribution Systems, MV Networks .................. 105
3.1 Introduction ............................................. 105
3.2 Design of Networks ....................................... 107
3.2.1 Selection of Voltage .............................. 109
3.2.2 Overhead or Underground ........................... 110
3.2.3 Sizing of Distribution Substations ................ 110
3.2.4 Connecting the MV (The Upstream Structure) ........ 114
3.2.5 The Required Performance of the Network ........... 116
3.2.6 The Network Complexity Factor ..................... 117
3.2.7 Voltage Control ................................... 121
3.2.8 Current Loading ................................... 128
3.2.9 Load Growth ....................................... 129
3.2.10 Earthing (Grounding) .............................. 131
3.2.11 Lost Energy ....................................... 132
3.2.12 Comparison of U.K. and U.S. Networks .............. 137
3.2.13 The Cost of Installation of the Selected Design ... 140
3.2.14 The Cost of Owning the Network after
Construction ...................................... 141
3.3 LV Distribution Networks ................................. 142
3.3.1 Underground LV Distribution Networks .............. 142
3.3.2 Overhead LV Distribution Networks ................. 143
3.4 Switchgear for Distribution Substations and LV
Networks ................................................. 145
3.5 Extended Control of Distribution Substations and LV
Networks ................................................. 146
3.6 Summary .................................................. 148
References .................................................... 148
Chapter 4. Hardware for Distribution Systems .................. 149
4.1 Introduction to Switchgear ............................... 149
4.1.1 Arc Interruption Methods .......................... 150
4.2 Primary Switchgear ....................................... 154
4.2.1 Substation Circuit Breakers ....................... 154
4.2.2 Substation Disconnectors .......................... 158
4.3 Ground-Mounted Network Substations ....................... 158
4.3.1 Ring Main Unit .................................... 160
4.3.2 Pad-Mount Switchgear .............................. 163
4.4 Larger Distribution/Compact Substations .................. 164
4.5 Pole-Mounted Enclosed Switches ........................... 167
4.6 Pole-Mounted Reclosers ................................... 168
4.6.1 Single-Tank Design ................................ 169
4.6.2 Individual Pole Design ............................ 169
4.7 Pole-Mounted Switch Disconnectors and Disconnectors ...... 170
4.8 Operating Mechanisms and Actuators ....................... 171
4.8.1 Motorized Actuators ............................... 172
4.8.2 Magnetic Actuators ................................ 173
4.9 Current and Voltage Measuring Devices .................... 175
4.9.1 Electromagnetic Current Transformers .............. 177
4.9.2 Voltage Transformers .............................. 180
4.10 Instrument Transformers in Extended Control .............. 181
4.11 Current and Voltage Sensors .............................. 182
4.11.1 Current Sensor .................................... 182
4.11.2 Voltage Sensor .................................... 183
4.11.3 Combi Sensor and Sensor Packaging ................. 184
Reference ..................................................... 185
Chapter 5. Protection and Control ............................. 187
5.1 Introduction ............................................. 187
5.2 Protection Using Relays .................................. 187
5.2.1 Discrimination by Time ............................ 188
5.2.2 Discrimination by Current ......................... 189
5.2.3 Discrimination by Both Time and Current ........... 189
5.2.1 Sensitive Earth Fault and Instantaneous
Protection Schemes ................................ 190
5.4 Protection Using Fuses ................................... 192
5.5 Earth Fault and Overcurrent Protection for Solid/
Resistance Earthed Networks .............................. 197
5.6 Earth Faults on Compensated Networks ..................... 198
5.7 Earth Faults on Unearthed Networks ....................... 203
5.8 An Earth Fault Relay for Compensated and Unearthed
Networks ................................................. 204
5.9 Fault Passage Indication ................................. 207
5.9.1 The Need for FPI on Distribution Networks with
Manual Control .................................... 207
5.9.2 What Is the Fault Passage Indicator, Then? ........ 209
5.9.3 The Need for FPI on Distribution Networks with
Extended Control or Automation .................... 211
5.9.4 Fault Passage Indicators for Use on Closed Loop
Networks .......................................... 212
5.9.5 Other Applications of Directional Indicators ...... 213
5.10 Connection of the» FPI to the Distribution System
Conductor ................................................ 214
5.10.1 Connection Using Current Transformers ............. 214
5.10.2 Connections Using CTs on Underground Systems ...... 215
5.10.3 Connections Using CTs on Overhead Systems ......... 216
5.10.4 Connection without CTs on Overhead Systems
(Proximity) ....................................... 216
5.11 Distribution System Earthing and Fault Passage
Indication ............................................... 218
5.11.1 Detection of Steady-State Fault Conditions ........ 220
5.11.2 Detection of Transient Fault Conditions ........... 221
5.11.3 Indication of Sensitive Earth Faults .............. 222
5.12 AutoReclosing and Fault Passage Indicators ............... 222
5.13 The Choice of Indication between Phase Fault and Earth
Fault .................................................... 223
5.14 Resetting the Fault Passage Indicator .................... 224
5.15 Grading of Fault Passage Indicators ...................... 224
5.16 Selecting a Fault Passage Indicator ...................... 225
5.17 Intelligent Electronic Devices ........................... 225
5.17.1 Remote Terminal Unit .............................. 226
5.17.2 Protection-Based IED .............................. 229
5.18 Power Supplies for Extended Control ...................... 229
5.19 Automation Ready Switchgear - FA Building Blocks ......... 234
5.19.1 Switch Options .................................... 237
5.19.2 Drive (Actuator) Options .......................... 237
5.19.3 RTU Options ....................................... 237
5.19.4 CT/VT Options ..................................... 237
5.19.5 Communications Options ............................ 238
5.19.6 FPI Options ....................................... 238
5.19.7 Battery Options ................................... 238
5.19.8 Interfaces within Building Blocks ................. 238
5.19.1 Examples of Building Blocks ....................... 239
5.20 Examples of Building Blocks .............................. 239
5.21 Typical Inputs and Outputs for Building Blocks ........... 241
5.21.1 Sectionalizing Switch (No Measurements) ........... 241
5.21.2 Sectionalizing Switch (with Measurements) ......... 242
5.21.3 Protection-Based Recloser for Overhead Systems .... 243
5.22 Control Building Blocks and Retrofit ..................... 244
5.23 Control Logic ............................................ 244
5.23.1 Option 1, Circuit A with 1.5 Switch Automation,
FPI and Remote Control of Switches ................ 245
5.23.2 Option 2, Circuit В with 2.5 Switch Automation,
FPI and Remote Control of Switches ................ 246
5.23.3 Options 3 and 4, No Fault Passage Indicators ...... 247
5.23.4 Options 5 and 7, Local Control Only ............... 248
5.23.5 Options 6 and 8, Local Control Only ............... 249
5.23.6 Special Case of Multishot Reclosing and
Automatic Sectionalizing .......................... 249
Chapter 6. Performance of Distribution Systems ............... 251
6.1 Faults on Distribution Networks .......................... 251
6.1.1 Types of Faults ................................... 251
6.1.2 The Effects of Faults ............................. 254
6.1.3 Transient Faults, Reclosers, and Compensated
Networks .......................................... 254
6.2 Performance and Basic Reliability Calculations ........... 259
6.2.1 System Indices .................................... 259
6.2.2 Calculating the Reliability Performance of
Networks .......................................... 260
6.2.3 Calculation of Sustained Interruptions (SAIDI) .... 261
6.2.4 Calculation of Sustained Interruption Frequency
(SAIFI) ........................................... 263
6.2.5 Calculation of Momentary Interruption Frequency
(MAIFI) ........................................... 264
6.2.6 Summary of Calculated Results ..................... 264
6.2.7 Calculating the Effects of Extended Control ....... 266
6.2.8 Performance as a Function of Network Complexity
Factor ............................................ 267
6.2.9 Improving Performance without Automation .......... 268
6.3 Improving the Reliability of Underground Networks ........ 272
6.3.1 Design Method 1 - Addition of Manually Operated
Sectionalizing Switches ........................... 272
6.3.2 Design Method 2 - Addition of Manually Switched
Alternative Supply ................................ 273
6.3.3 Design Method 3 - Add Automatic in Line
Protection ........................................ 274
6.3.4 Design Method 4 - Add Continuous Alternative
Supply ............................................ 275
6.4 Improving the Reliability of Overhead Networks (Design
Methods 5, 6, and 7) ..................................... 278
6.5 Improving Performance with Automation .................... 281
6.6 Improvements by Combining Design Methods 1, 2, 3, 4,
and on Underground Circuits .............................. 282
References .................................................... 287
Chapter 7. Communication Systems for Control and Automation ... 289
7.1 Introduction ............................................. 289
7.2 Communications and Distribution Automation ............... 289
7.3 DA Communication Physical Link Options ................... 292
7.4 Wireless Communication ................................... 293
7.4.1 Unlicensed Spread Spectrum Radio .................. 293
7.4.2 VHF, UHF Narrow Bandwidth Packaged Data Radio
(Licensed/Unlicensed) ............................. 293
7.4.3 Radio Network Theory .............................. 293
7.4.5 Trunked Systems (Public Packet-Switched Radio) .... 302
7.4.6 Cellular .......................................... 303
7.4.7 Paging Technology ................................. 303
7.4.8 Satellite Communications - Low Earth Orbit ........ 303
7.5 Wire Communications ...................................... 304
7.5.1 Telephone Line .................................... 304
7.5.2 Fiber Optics ...................................... 304
7.5.3 Distribution Line Carrier ......................... 304
7.5.4 Summary of Communications Options ................. 331
7.6 Distribution Automation Communications Protocols ......... 333
7.6.1 MODBUS ............................................ 333
7.6.2 DNP 3.0 ........................................... 336
7.6.3 IEC 60870-5-101 ................................... 342
7.6.4 UCA 2.0, IEC 61850 ................................ 345
7.7 Distribution Automation Communications Architecture ...... 346
7.7.1 Central DMS Communication ......................... 346
7.7.2 Polling and Report by Exception ................... 348
7.7.3 Intelligent Node Controllers/Gateways ............. 349
7.7.4 Interconnection of Heterogeneous Protocols ........ 349
7.8 DA Communications User Interface ......................... 350
7.9 Some Considerations for DA Communications Selection ...... 350
7.10 Requirements for Dimensioning the Communication
Channel .................................................. 351
7.10.1 Confirmed and Nonconfirmed Communication ......... 351
7.10.2 Characterization of Communication Systems ........ 351
7.10.3 Communication Model .............................. 353
7.10.4 Calculation of the Reaction or the Response
Time ............................................. 353
Chapter 8. Creating the Business Case ......................... 357
8.1 Introduction ............................................. 357
8.2 Potential Benefits Perceived by the Industry for
Substation Automation .................................... 358
8.2.1 Integration and Functional Benefits of
Substation Control and Automation ................. 358
8.2.2 SCADA vs. SA ...................................... 360
8.2.3 Economic Benefits Claimed by the Industry ......... 360
8.3 Potential Benefits Perceived by the Industry for Feeder
Automation ............................................... 363
8.4 Generic Benefits ......................................... 364
8.5 Benefit Opportunity Matrix ............................... 367
8.6 Benefit Flowchart ........................................ 367
8.7 Dependencies, and Shared and Unshared Benefits ........... 367
8.7.1 Dependencies ...................................... 367
8.7.2 Shared Benefits ................................... 371
8.7.3 Unshared Benefits from Major DA Functions ......... 372
8.7.4 Benefit Summary ................................... 378
8.8 Capital Deferral, Release, or Displacement ............... 379
8.8.1 Deferral of Primary Substation Capital
Investment ........................................ 379
8.8.2 Release of Distribution Network Capacity .......... 383
8.8.3 Release of Upstream Network and System Capacity ... 387
8.8.4 Displacement of Conventional Equipment with
Automation ........................................ 388
8.9 Savings in Personnel ..................................... 388
8.9.1 Reduction in Substation/Control Center Operating
Levels ............................................ 389
8.9.2 Reduction in Inspection Visits .................... 389
8.9.3 Reduction in Crew Time ............................ 390
8.9.4 Calculation of Crew Times Savings Associated
with Investment- and Operation-Related Savings .... 402
8.9.5 Reduced Crew Time and Effort for Changing Relay
Settings for CLPU ................................. 402
8.10 Savings Related to Energy ................................ 403
8.10.1 Reduction in Energy Not Supplied Savings Due to
Faster Restoration ................................ 403
8.10.2 Reduced Energy Revenue Due to Controlled Load
Reduction ......................................... 404
8.10.3 Energy Savings Due to Technical Loss Reduction .... 405
8.10.3.1 Loss Reduction from Feeder Volt/VAR
Control .................................. 405
8.11 Other Operating Benefits ................................. 407
8.11.1 Repair and Maintenance Benefits ................... 408
8.11.2 Benefits from Better Information (DMOL) ........... 408
8.11.3 Improved Customer Relationship Management ......... 410
8.12 Summary of DA Functions and Benefits ..................... 411
8.13 Economic Value - Cost .................................... 412
8.13.1 Utility Cost ...................................... 413
8.13.2 Customer Cost ..................................... 421
8.13.3 Economic Value .................................... 422
8.14 Presentation of Results and Conclusions .................. 426
References ............................................... 428
Chapter 9. Case Studies ....................................... 431
9.1 Introduction ............................................. 431
9.2 Case Study 1, Long Rural Feeder .......................... 431
9.2.1 Evaluation of Performance ......................... 431
9.2.2 Crew Time Savings ................................. 433
9.2.3 Network Performance and Penalties ................. 434
9.3 Case Study 2, Large Urban Network ........................ 437
9.3.1 Preparation Analysis - Crew Time Savings .......... 437
9.3.2 Preparation Analysis - Network Performance ........ 439
9.3.5 Summary of Cost Savings ........................... 446
9.3.6 Cost of SCADA/DMS System .......................... 447
9.3.7 Cost Benefits and Payback Period .................. 448
9.3.8 Conclusions ....................................... 448
Glossary ...................................................... 451
Index ......................................................... 459
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