Preface xvii -- 1 POWER SYSTEM DISTURBANCE ANALYSIS FUNCTION 1 -- 1.1 Analysis Function of Power System Disturbances 2 -- 1.2 Objective of DFR Disturbance Analysis 4 -- 1.3 Determination of Power System Equipment Health Through System Disturbance Analysis 5 -- 1.4 Description of DFR Equipment 6 -- 1.5 Information Required for the Analysis of System Disturbances 7 -- 1.6 Signals to be Monitored by a Fault Recorder 8 -- 1.7 DFR Trigger Settings of Monitored Voltages and Currents 10 -- 1.8 DFR and Numerical Relay Sampling Rate and Frequency Response 11 -- 1.9 Oscillography Fault Records Generated by Numerical Relaying 11 -- 1.10 Integration and Coordination of Data Collected from Intelligent Electronic Devices 12 -- 1.11 DFR Software Analysis Packages 12 -- 1.12 Verification of DFR Accuracy in Monitoring Substation Ground Currents 21 -- 1.13 Using DFR Records to Validate Power System Short-Circuit Study Models 24 -- 1.14 COMTRADE Standard 31 -- 2 PHENOMENA RELATED TO SYSTEM FAULTS AND THE PROCESS OF CLEARING FAULTS FROM A POWER SYSTEM 33 -- 2.1 Shunt Fault Types Occurring in a Power System 33 -- 2.2 Classification of Shunt Faults 34 -- 2.3 Types of Series Unbalance in a Power System 39 -- 2.4 Causes of Disturbance in a Power System 39 -- 2.5 Fault Incident Point 40 -- 2.6 Symmetric and Asymmetric Fault Currents 41 -- 2.7 Arc-Over or Flashover at the Voltage Peak 44 -- 2.8 Evolving Faults 48 -- 2.9 Simultaneous Faults 51 -- 2.10 Solid or Bolted (RF1/40) Close-in Phase-to-Ground Faults 52 -- 2.11 Sequential Clearing Leading to a Stub Fault that Shows a Solid (RF1/40) Remote Line-to-Ground Fault 53 -- 2.12 Sequential Clearing Leading to a Stub Fault that Shows a Resistive Remote Line-to-Ground Fault 54 -- 2.13 High-Resistance Tree Line-to-Ground Faults 56 -- 2.14 High-Resistance Line-to-Ground Fault Confirming the Resistive Nature of the Fault Impedance When Fed from One Side Only (Stub) 58 -- 2.15 Phase-to-Ground Faults on an Ungrounded System 59 -- 2.16 Current in Unfaulted Phases During Line-to-Ground Faults 60.

2.17 Line-to-Ground Fault on the Grounded-Wye (GY) Side of a Delta/GY Transformer 63 -- 2.18 Line-to-Line Fault on the Grounded-Wye Side of a Delta/GY Transformer 65 -- 2.19 Line-to-Line Fault on the Delta Side of a Delta/GY Transformer with No Source Connected to the Delta Winding 66 -- 2.20 Subcycle Relay Operating Time During an EHV Double-Phase-to-Ground Fault 68 -- 2.21 Self-Clearing of a C-g Fault Inside an Oil Circuit Breaker Tank 69 -- 2.22 Self-Clearing of a B-g Fault Caused by a Line Insulator Flashover 70 -- 2.23 Delayed Clearing of a Pilot Scheme Due to a Delayed Communication Signal 71 -- 2.24 Sequential Clearing of a Line-to-Ground Fault 72 -- 2.25 Step-Distance Clearing of an L-g Fault 74 -- 2.26 Ground Fault Clearing in Steps by an Instantaneous Ground Element at One End and a Ground Time Overcurrent Element at the Other End 76 -- 2.27 Ground Fault Clearing by Remote Backup Following the Failures of Both Primary and Local Backup (Breaker Failure) Protection Systems 78 -- 2.28 Breaker Failure Clearing of a Line-to-Ground Fault 79 -- 2.29 Determination of the Fault Incident Point and Classification of Faults Using a Comparison Method 81 -- 3 POWER SYSTEM PHENOMENA AND THEIR IMPACT ON RELAY SYSTEM PERFORMANCE 85 -- 3.1 Power System Oscillations Leading to Simultaneous Tripping of Both Ends of a Transmission Line and the Tripping of One End Only on an Adjacent Line 86 -- 3.2 Generator Oscillations Triggered by a Combination of L-g Fault, Loss of Generation, and Undesired Tripping of Three 138-kV Lines 91 -- 3.3 Stable Power Swing Generated During Successful Synchronization of a 200-MW Unit 95 -- 3.4 Major System Disturbance Leading to Different Oscillations for Different Transmission Lines Emanating from the Same Substation 96 -- 3.5 Appearance of 120-Hz Current at a Generator Rotor During a High-Side Phase-to-Ground Fault 98 -- 3.6 Generator Negative-Sequence Current Flow During Unbalanced Faults 101 -- 3.7 Inadvertent (Accidental) Energization of a 170-MW Hydro Generating Unit 102.

3.8 Appearance of Third-Harmonic Voltage at Generator Neutral 104 -- 3.9 Variations of Generator Neutral Third-Harmonic Voltage Magnitude During System Faults 106 -- 3.10 Generator Active and Reactive Power Outputs During a GSU High-Side L-g Fault 107 -- 3.11 Loss of Excitation of a 200-MW Unit 108 -- 3.12 Generator Trapped (Decayed) Energy 110 -- 3.13 Nonzero Current Crossing During Faults and Mis-Synchronization Events 112 -- 3.14 Generator Neutral Zero-Sequence Voltage Coupling Through Step-Up Transformer Interwinding Capacitance During a High-Side Ground Fault 113 -- 3.15 Energizing a Transformer with a Fault on the High Side within the Differential Zone 115 -- 3.16 Transformer Inrush Currents 118 -- 3.17 Inrush Currents During Energization of the Grounded-Wye Side of a YG/Delta Transformer 120 -- 3.18 Inrush Currents During Energization of a Transformer Delta Side 121 -- 3.19 Two-Phase Energization of an Autotransformer with a Delta Winding Tertiary During a Simultaneous L-g Fault and an Open Phase 124 -- 3.20 Phase Shift of 30Across the Delta/Wye Transformer Banks 127 -- 3.21 Zero-Sequence Current Contribution from a Remote Two-Winding Delta/YG Transformer 128 -- 3.22 Conventional Power-Regulating Transformer Core Type Acting as a Zero-Sequence Source 129 -- 3.23 Circuit Breaker Re-Strikes 130 -- 3.24 Circuit Breaker Pole Disagreement During a Closing Operation 132 -- 3.25 Circuit Breaker Opening Resistors 133 -- 3.26 Secondary Current Backfeeding to Breaker Failure Fault Detectors 134 -- 3.27 Magnetic Flux Cancellation 136 -- 3.28 Current Transformer Saturation 138 -- 3.29 Current Transformer Saturation During an Out-of-Step System Condition Initiated by Mis-Synchronization of a Generator Breaker 141 -- 3.30 Capacitive Voltage Transformer Transient 143 -- 3.31 Bushing Potential Device Transient During Deenergization of an EHV Line 144 -- 3.32 Capacitor Bank Breaker Re-Strike Following Interruption of a Capacitor Normal Current 146 -- 3.33 Capacitor Bank Closing Transient 147.

3.34 Shunt Capacitor Bank Outrush into Close-in System Faults 149 -- 3.35 SCADA Closing into a Three-Phase Fault 153 -- 3.36 Automatic Reclosing into a Permanent Line-to-Ground Fault 154 -- 3.37 Successful High-Speed Reclosing Following a Line-to-Ground Fault 155 -- 3.38 Zero-Sequence Mutual Coupling¿́¿Induced Voltage 156 -- 3.39 Mutual Coupling Phenomenon Causing False Tripping of a High-Impedance Bus Differential Relay During a Line Phase-to-Ground Fault 159 -- 3.40 Appearance of Nonsinusoidal Neutral Current During the Clearing of Three-Phase Faults 162 -- 3.41 Current Reversal on Parallel Lines During Faults 164 -- 3.42 Ferranti Voltage Rise 166 -- 3.43 Voltage Oscillation on EHV Lines Having Shunt Reactors at their Ends 168 -- 3.44 Lightning Strike on an Adjacent Line Followed by a C-g Fault Caused by a Separate Lightning Strike on the Monitored Line 172 -- 3.45 Spill Over of a 345-kV Surge Arrester Used to Protect a Cable Connection, Prior to its Failure 173 -- 3.46 Scale Saturation of an A/D Converter Caused by a Calibration Setting Error 174 -- 3.47 Appearance of Subsidence Current at the Instant of Fault Interruption 176 -- 3.48 Energizing of a Medium Voltage Motor that has an Incorrect Formation of the Stator Winding Neutral 177 -- 3.49 Phase Angle Change from Loading Condition to Fault Condition 179 -- 4 CASE STUDIES RELATED TO GENERATOR SYSTEM DISTURBANCES 183 -- 4.1 Generator Protection Basics 184 -- Case Studies 186 -- Case Study 4.1 Appearance of Double-Frequency (120-Hz) Current in a Hydrogenerator Rotor Due to Stator Negative-Sequence Current Flow During a 115-kV Phase-to-Ground Fault 186 -- Case Study 4.2 Inadvertent (Accidental) Energization of a 170-MW Hydro Unit 193 -- Case Study 4.3 Loss of Excitation for a 200-MW Generating Unit Caused by Human Error 204 -- Case Study 4.4 Loss-of-Excitation Trip in an 1100-MW Unit 212 -- Case Study 4.5 Mis-synchronization of a 50-MW Steam Unit for a Combined-Cycle Plant 214 -- Case Study 4.6 Mis-synchronization of a 200-MW Hydro Unit 222.

Case Study 4.7 Undesired Tripping of a Numerical Differential Relay During Manual Synchronization of a Hydro Unit 231 -- Case Study 4.8 Tripping of a 500-MW Combined-Cycle Plant Triggered by a High-Side 138-kV Phase-to-Ground Fault 236 -- Case Study 4.9 Tripping of a 110-MW Combustion Turbine Unit in a Combined-Cycle Plant During a Power Swing 244 -- Case Study 4.10 Analysis of an 800-MW Generating Plant DFR Record for a Normally Cleared 345-kV Phase-to-Ground Fault 247 -- Case Study 4.11 Tripping of a 150-MW Combined-Cycle Plant Due to a Failed Lead of One Generator Terminal Surge Capacitor 250 -- Case Study 4.12 Generator Stator Ground Fault in an 800-MW Fossil Unit 260 -- Case Study 4.13 Three-Phase Fault at the Terminal of an 800-MW Generator Unit 265 -- Case Study 4.14 Three-Phase Fault at the Terminal of a 50-MW Generator Due to a Cable Connection Failure 271 -- Case Study 4.15 Generator Stator Phase-to-Phase-to-Ground Fault Caused by Failure of the Rotor Fan Blade 276 -- Case Study 4.16 Undesired Tripping of a Pump Storage Plant During a Close-in Phase-to-Ground 345-kV Line Fault 286 -- Case Study 4.17 Tripping of an 800-MW Plant and the Associated EHV Lines During a 345-kV Bus Fault 293 -- Case Study 4.18 Tripping of a 150-MW Combined-Cycle Plant During an External 138-kV Three-Phase Fault 296 -- Case Study 4.19 Tripping of a 150-MW Combined-Cycle Plant During a Disturbance in the 138-kV Transmission System 303 -- Case Study 4.20 Undesired Tripping of a 150-MW Combined-Cycle Plant Following Successful Clearing of a 138-kV Double-Phase-to-Ground Fault 308 -- Case Study 4.21 Undesired Tripping of an Induction Generator by a Differential Relay Having a Capacitor Bank Within the Protection Zone 311 -- Case Study 4.22 Undesired Tripping of a Steam Unit Upon Its First Synchronization to the System During the Commissioning Phase of a Combined-Cycle Plant 314 -- Case Study 4.23 Sequential Shutdown of a Steam-Driven Generating Unit as Part of a 500-MWCombined-Cycle Plant 318.

Case Study 4.24 Wiring Errors Leading to Undesired Generator Numerical Differential Relay Operation During the Commissioning Phase of a New Unit 320 -- Case Study 4.25 Phasing a New Generator into the System Prior to Commissioning 324 -- Case Study 4.26 Third-Harmonic Undervoltage Element Setting Procedure for 100% Stator Ground Fault Protection 327 -- Case Study 4.27 Basis for Setting the Generator Relaying Elements to Provide System Backup Protection 330 -- 5 CASE STUDIES RELATED TO TRANSFORMER SYSTEM DISTURBANCES 335 -- 5.1 Transformer Basics 336 -- 5.2 Transformer Differential Protection Basics 344 -- 5.3 Case Studies 347 -- Case Study 5.1 Energization of a 5-MVA 13.8/4.16-kV Station Service Transformer with a 13.8-kV Phase-to-Phase Bus Fault Within the Transformer Differential Protection Zone 347 -- Case Study 5.2 Lack of Protection Redundancy for a Generator Step-up Transformer Leads to Interruption of a 230-kV Area 353 -- Case Study 5.3 Undesired Operation of a Numerical Transformer Differential Relay Due to a Relay Setting Error in the Winding Configuration 357 -- Case Study 5.4 Location of a 13.8-kV Switchgear Phase-to-Phase Fault Using Transformer Differential Numerical Relay Fault Records 363 -- Case Study 5.5 Operation of a Unit Step-Up Transformer with an Open Phase on the 13.8-kV Delta Winding 370 -- Case Study 5.6 Using a Transformer Phasing Diagram, Digital Fault Recorder Record, and Relay Targets to Confirm the Damaged Phase of a Unit Auxiliary Transformer Failure 375 -- Case Study 5.7 Failure of a 450-MVA 345/138/13.2-kV Autotransformer 381 -- Case Study 5.8 Failure of a 750-kVA 13.8/0.480-kV Station Service Transformer Due to a Possible Ferroresonance Condition 387 -- Case Study 5.9 Undesired Tripping of a Numerical Transformer Differential Relay During an External Line-to-Ground Fault 394 -- Case Study 5.10 Undesired Operation of Numerical Transformer Differential Relays During Energization of Two 75-MVA 138/13.8-kV GSU Transformers 407 -- Case Study 5.11 Undesired Operation of a Numerical Transformer Differential Relay During Energization of a 5-MVA 13.8/4.16-kV Station Service Transformer 411.

Case Study 5.12 Phase-to-Phase Fault Evolving into a Three-Phase Fault at the High Side of a 5-MVA 13.8/4.16-kV Station Service Transformer 414 -- Case Study 5.13 Phase-to-Phase Fault Evolving into a Three-Phase Fault at the 13.8-kV Bus Connection of a 2-MVA 13.8/0.480-kV Station Service Enclosure 420 -- Case Study 5.14 Phase-to-Phase Fault in a 13.8-kV Switchgear Caused by Heavy Rain Evolving into a Three-Phase Fault 426 -- Case Study 5.15 Undesired Operation of a Numerical Transformer Differential Relay Due to a Missing CT Cable Connection as an Input to the Relay Wiring 430 -- Case Study 5.16 Phase-to-Ground Fault Caused by Flashover of a Transformer 115-kV Bushing Due to a Bird Droppings 434 -- Case Study 5.17 Using a Transformer Numerical Relay Oscillography Record to Analyze Phase-to-Ground Faults in a 4.16-kV Low-Resistance Grounding Supply 439 -- Case Study 5.18 Phase-to-Phase Fault Caused by a Squirrel in a 13.8-kVCable Bus Which Evolves into a Three-Phase Fault 447 -- Case Study 5.19 13.8-kV Transformer Lead Phase-to-Phase Fault Due to Animal Contact, Evolving into a 115-kV Transformer Bushing Fault 451 -- Case Study 5.20 Undesired Tripping of a Numerical Multifunction Transformer Relay by Assertion of a Digital Input Wired to the Buchholz Relay Trip Output 456 -- 6 CASE STUDIES RELATED TO OVERHEAD TRANSMISSION-LINE SYSTEM DISTURBANCES 461 -- 6.1 Line Protection Basics 463 -- 6.2 Case Studies 466 -- Case Study 6.1 Using a DFR Record From One End Only to Determine Local and Remote-End Clearing Times for a Line-to-Ground Fault 466 -- Case Study 6.2 Analysis of Clearing Times for a Phase-to-Ground Fault from Both Ends of a 345-kV Transmission Line Using Oscillograms from One End Only 469 -- Case Study 6.3 Analysis of a Three-Phase Fault Caused by Lightning 471 -- Case Study 6.4 Analysis of a Double-Phase-to-Ground 765-kV Fault Caused by Lightning 473 -- Case Study 6.5 Assessment of Transmission Tower Footing Resistance by Analyzing a Three-Phase-to-Ground Fault Caused by Lightning 476.

Case Study 6.6 115-kV Phase-to-Ground Fault Cleared First from a Solidly Grounded System, Then Connected and Cleared from an Ungrounded System 478 -- Case Study 6.7 345-kV Phase-to-Ground Fault (C-g) Caused by an Act of Vandalism 485 -- Case Study 6.8 345-kV Phase-to-Ground (A-g) Fault Due to an Accident Along the Line Right-of-Way 489 -- Case Study 6.9 False Tripping of a 138-kV Current Differential Relaying System During an External Phase-to-Ground Fault 495 -- Case Study 6.10 Undesired Operation of a 13.8-kV Feeder Ground Relay During a Three-Phase Fault Due to an Extra CT Circuit Ground 502 -- Case Study 6.11 Correction of a System Model Error from Analysis of a Failure of a Post Insulator Associated with a 115-kV Disconnect Switch 512 -- Case Study 6.12 Location of a 345-kV Line Fault Protected by Electromechanical Distance Relays Using Information from a DFR Record 519 -- Case Study 6.13 Location of an Outdoor 13.8-kV Switchgear Fault at a Cogeneration Facility Using a DFR Fault Record from a Remote Substation 524 -- Case Study 6.14 Breakage (Failure) of a 345-kV Subconductor Bundle During a High-Resistance Tree Fault, Due to the Heavily Loaded Line Sagging to a Tree 529 -- Case Study 6.15 115-kV Phase-to-Phase Fault Caused by Failure of a Circuit Switcher 536 -- Case Study 6.16 Undesired Tripping of a 115-kV Feeder Due to a Setting Application Error in the Time Overcurrent Element for a Numerical Line Protection Relay 539 -- Case Study 6.17 Mitigation of Mutual Coupling Effects on the Reach of Ground Distance Relays Protecting Highand Extrahigh-Voltage Transmission Lines 544 -- 7 CASE STUDIES RELATED TO CABLE TRANSMISSION FEEDER SYSTEM DISTURBANCES 571 -- Case Studies 572 -- Case Study 7.1 Optimum Design of Relaying Protection Zones Leads to Quick Identification of a Faulted 345-kV Submarine Cable Section 572 -- Case Study 7.2 Undesired Operation of a 138-kV Cable Feeder Differential Relay During the Commissioning Phase of a 500-MW Plant 578 -- Case Study 7.3 Phase-to-Ground Fault Caused by Failure of a 345-kV Cable Connection Between the Generator and the Switchyard, Accompanied by Mechanical Failure of One of the Cable Pot Head Phases 588.

Case Study 7.4 Troubleshooting a 345-kV Phase-to-Ground Fault Using Relay Targets Only 595 -- Case Study 7.5 Failure of a 345-kV Cable Connection Between a 300-MW Generator and a 345-kV Switchyard, Causing a Phase-to-Ground Fault 603 -- Case Study 7.6 138-kV Cable Pot Head Failure Analysis Using Numerical Current Differential Relay Oscillography and Event Records 607 -- 8 CASE STUDIES RELATED TO BREAKER FAILURE PROTECTION SYSTEM DISTURBANCES 615 -- 8.1 Breaker Failure Protection Basics 616 -- Case Studies 626 -- Case Study 8.1 Tripping of a Combined-Cycle 150-MW Plant by Undesired Operation of a Solid-State Breaker Failure Relaying System 626 -- Case Study 8.2 115-kV Dual Breaker Failures Resulting in the Loss of a 1000-MW Plant and Associated Substations 634 -- Case Study 8.3 230-kV Substation Outage Due to Circuit Breaker Problems During the Clearing of a Close-in Phase-to-Ground Fault 640 -- Case Study 8.4 Failure of a 230-kV Circuit Breaker Leading to Isolation of a 1000-MW Plant and Associated Substations 646 -- Case Study 8.5 Generator CB Failure During Automatic Synchronization of the Circuit Breaker 654 -- Case Study 8.6 Circuit Breaker Re-strikes While Clearing Simultaneous Phase-to-Ground Faults on a 230-kV Double-Circuit Tower 660 -- Case Study 8.7 345-kV Capacitor Bank Breaker Fault Coupled with an Additional Failure of a Dual SF6 Pressure 345-kV Breaker During the Clearing of the Fault 664 -- Case Study 8.8 Oil Circuit Breaker Failure Following the Clearing of a Failed 230-kV Surge Arrester 671 -- Case Study 8.9 Detection of a Remote Circuit Breaker Problem from Analysis of a Local Oscillogram Monitoring Line Currents and Voltages 676 -- Case Study 8.10 Blackout of a 138-kV Load Area Due to a Primary Relay System Failure and the Lack of DC Control Power for the Secondary Relay System Circuit 678 -- Case Study 8.11 Installation of Two 345-kV Breakers in Series Within a Ring Substation Configuration to Mitigate the Loss of Critical Lines During Breaker Failure Events 682.

Case Study 8.12 Design of Two 138-kV Circuit Breakers in Series to Fulfill the Need of Breaker Failure Protection 682 -- 9 PROBLEMS 685 -- Index 715.