Power System Phenomena and their Impact on Relay System Performance

This chapter contains sections titled:

• 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

• Generator Oscillations Triggered by a Combination of L-g Fault, Loss of Generation, and Undesired Tripping of Three 138-kV Lines

• Stable Power Swing Generated During Successful Synchronization of a 200-MW Unit

• Major System Disturbance Leading to Different Oscillations for Different Transmission Lines Emanating from the Same Substation

• Appearance of 120-Hz Current at a Generator Rotor During a High-Side Phase-to-Ground Fault

• Generator Negative-Sequence Current Flow During Unbalanced Faults

• Inadvertent (Accidental) Energization of a 170-MW Hydro Generating Unit

• Appearance of Third-Harmonic Voltage at Generator Neutral

• Variations of Generator Neutral Third-Harmonic Voltage Magnitude During System Faults

• Generator Active and Reactive Power Outputs During a GSU High-Side L-g Fault

• Loss of Excitation of a 200-MW Unit

• Generator Trapped (Decayed) Energy

• Nonzero Current Crossing During Faults and Mis-Synchronization Events

• Generator Neutral Zero-Sequence Voltage Coupling Through Step-Up Transformer Interwinding Capacitance During a High-Side Ground Fault

• Energizing a Transformer with a Fault on the High Side within the Differential Zone

• Transformer Inrush Currents

• Inrush Currents During Energization of the Grounded-Wye Side of a YG/Delta Transformer

• Inrush Currents During Energization of a Transformer Delta Side

• Two-Phase Energization of an Autotransformer with a Delta Winding Tertiary During a Simultaneous L-g Fault and an Open Phase

• Phase Shift of 30?? Across the Delta/Wye Transformer Banks

• Zero-Sequence Current Contribution from a Remote Two-Winding Delta/YG Transformer

• Conventional Power-Regulating Transformer Core Type Acting as a Zero-Sequence Source

• Circuit Breaker Re-Strikes

• Circuit Breaker Pole Disagreement During a Closing Operation

• Circuit Breaker Opening Resistors

• Secondary Current Backfeeding to Breaker Failure Fault Detectors

• Magnetic Flux Cancellation

• Current Transformer Saturation

• Current Transformer Saturation During an Out-of-Step System Condition Initiated by Mis-Synchronization of a Generator Breaker

• Capacitive Voltage Transformer Transient

• Bushing Potential Device Transient During Deenergization of an EHV Line

• Capacitor Bank Breaker Re-Strike Following Interruption of a Capacitor Normal Current

• Capacitor Bank Closing Transient

• Shunt Capacitor Bank Outrush into Close-in System Faults

• SCADA Closing into a Three-Phase Fault

• Automatic Reclosing into a Permanent Line-to-Ground Fault

• Successful High-Speed Reclosing Following a Line-to-Ground Fault

• Zero-Sequence Mutual Coupling-Induced Voltage

• Mutual Coupling Phenomenon Causing False Tripping of a High-Impedance Bus Differential Relay During a Line Phase-to-Ground Fault

• Appearance of Nonsinusoidal Neutral Current During the Clearing of Three-Phase Faults

• Current Reversal on Parallel Lines During Faults

• Ferranti Voltage Rise

• Voltage Oscillation on EHV Lines Having Shunt Reactors at their Ends

• Lightning Strike on an Adjacent Line Followed by a C-g Fault Caused by a Separate Lightning Strike on the Monitored Line

• Spill Over of a 345-kV Surge Arrester Used to Protect a Cable Connection, Prior to its Failure

• Scale Saturation of an A/D Converter Caused by a Calibration Setting Error

• Appearance of Subsidence Current at the Instant of Fault Interruption

• Energizing of a Medium Voltage Motor that has an Incorrect Formation of the Stator Winding Neutral

• Phase Angle Change from Loading Condition to Fault Condition

• References