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Switching Capacitive and Light Inductive Currents€¦ · switching shunt capacitor banks, shunt...
Transcript of Switching Capacitive and Light Inductive Currents€¦ · switching shunt capacitor banks, shunt...
Page 1 Capacitor and Reactor Switching, J. H. Brunke, July 2008 Presented at IEEE Circuit Breaker Tutorial
Application of Power Circuit Breakers for Switching Capacitive and Light Inductive
CurrentsIEEE Circuit Breaker Tutorial
Dr. John H. Brunke, P.E.Fellow
Page 2 Capacitor and Reactor Switching, J. H. Brunke, July 2008 Presented at IEEE Circuit Breaker Tutorial
Nature of Capacitive and Small Inductive Currents
Small in magnitudeSome technologies use current to assist in interruption
Current and voltage 90 degrees out of phaseCircuit breakers frequently called upon to deal with switching these
currentsSwitching can result in extreme magnitudes of currents and extreme
rates of change of voltage
This presentation is based on C37.012 and C37.015, the application guides for switching these currents. It is impossible to cover all the material in these in detail, and there are other important issues with switching these currents that are not covered in the application guides. This presentation is intended to provide an overview of all the issues associated with switching these currents.
Page 3 Capacitor and Reactor Switching, J. H. Brunke, July 2008 Presented at IEEE Circuit Breaker Tutorial
Shunt Capacitor Bank SwitchingContinuous Current
Margins for capacitor toleranceMargins for harmonic currentMargin of 35% typical
Interrupting shunt capacitor bank current
Page 4 Capacitor and Reactor Switching, J. H. Brunke, July 2008 Presented at IEEE Circuit Breaker Tutorial
What is a Restrike?
Page 5 Capacitor and Reactor Switching, J. H. Brunke, July 2008 Presented at IEEE Circuit Breaker Tutorial
Restrike, Back to Back with CLR’s
Page 6 Capacitor and Reactor Switching, J. H. Brunke, July 2008 Presented at IEEE Circuit Breaker Tutorial
Energizing Shunt Capacitor Banks
Single or isolated bank
Back to back
Page 7 Capacitor and Reactor Switching, J. H. Brunke, July 2008 Presented at IEEE Circuit Breaker Tutorial
500 kV Single Bank Energization
Page 8 Capacitor and Reactor Switching, J. H. Brunke, July 2008 Presented at IEEE Circuit Breaker Tutorial
500 kV Back to Back Energization
Page 9 Capacitor and Reactor Switching, J. H. Brunke, July 2008 Presented at IEEE Circuit Breaker Tutorial
Consequences of Capacitor Inrush Transients
Dip to zero voltageInterference with devices that use zero crossing detectors
Back to back results in extremely high currentsDamage to primary and secondary equipmentSafety
Restrike (trapped charge)2 X the voltage, effects 2 X
Page 10 Capacitor and Reactor Switching, J. H. Brunke, July 2008 Presented at IEEE Circuit Breaker Tutorial
Mitigation of Closing TransientsClosing Resistor or Reactor
Fixed Current Limiting Reactor
Controlled closing
Page 11 Capacitor and Reactor Switching, J. H. Brunke, July 2008 Presented at IEEE Circuit Breaker Tutorial
500 kV Back to Back Energization with CLR
Page 12 Capacitor and Reactor Switching, J. H. Brunke, July 2008 Presented at IEEE Circuit Breaker Tutorial
Controlled Closing, Single Bank
Page 13 Capacitor and Reactor Switching, J. H. Brunke, July 2008 Presented at IEEE Circuit Breaker Tutorial
Controlled Closing, Back to Back
Page 14 Capacitor and Reactor Switching, J. H. Brunke, July 2008 Presented at IEEE Circuit Breaker Tutorial
Controlled Closing, Capacitor Banks, targeting
Page 15 Capacitor and Reactor Switching, J. H. Brunke, July 2008 Presented at IEEE Circuit Breaker Tutorial
Switching Capacitor Through a Transformer
Page 16 Capacitor and Reactor Switching, J. H. Brunke, July 2008 Presented at IEEE Circuit Breaker Tutorial
Faults Near Capacitor Banks
•Outrush, TRV effects, high source impedance voltage rises (or long lining), etc.
Page 17 Capacitor and Reactor Switching, J. H. Brunke, July 2008 Presented at IEEE Circuit Breaker Tutorial
Line Fault, 500 kV system, with 430 Mvar of Connected Capacitors
Page 18 Capacitor and Reactor Switching, J. H. Brunke, July 2008 Presented at IEEE Circuit Breaker Tutorial
Circuit Breaker StandardsRestrike probability: C0, no rating, C1, ~ 1 restrike in 50 operations, C2, ~ 1 restrike in 300 operations
Page 19 Capacitor and Reactor Switching, J. H. Brunke, July 2008 Presented at IEEE Circuit Breaker Tutorial
Circuit Breaker Standards
Page 20 Capacitor and Reactor Switching, J. H. Brunke, July 2008 Presented at IEEE Circuit Breaker Tutorial
Switching Overhead Transmission Lines - Interruption
Page 21 Capacitor and Reactor Switching, J. H. Brunke, July 2008 Presented at IEEE Circuit Breaker Tutorial
Switching Overhead Transmission Lines
Page 22 Capacitor and Reactor Switching, J. H. Brunke, July 2008 Presented at IEEE Circuit Breaker Tutorial
Charging Current and Recovery Voltage
Page 23 Capacitor and Reactor Switching, J. H. Brunke, July 2008 Presented at IEEE Circuit Breaker Tutorial
Recovery Voltage on Unfaulted Phases
Neutral shift, coupling of transients
Page 24 Capacitor and Reactor Switching, J. H. Brunke, July 2008 Presented at IEEE Circuit Breaker Tutorial
De-energization of a Line with Connected Transformer
Page 25 Capacitor and Reactor Switching, J. H. Brunke, July 2008 Presented at IEEE Circuit Breaker Tutorial
Energization of Transmission Lines, Switching Surges
Page 26 Capacitor and Reactor Switching, J. H. Brunke, July 2008 Presented at IEEE Circuit Breaker Tutorial
Switching Surge Overvoltages
Page 27 Capacitor and Reactor Switching, J. H. Brunke, July 2008 Presented at IEEE Circuit Breaker Tutorial
Switching Surge MitigationOnly needed above 245 kV (rarely at 245 kV)
Closing resistorsLine connected surge arrestersControlled closingTrapped charge reduction (line connected PT’s – caution)Single pole reclosing (limited due to secondary arc)Controlled closingStaggered pole closing
Page 28 Capacitor and Reactor Switching, J. H. Brunke, July 2008 Presented at IEEE Circuit Breaker Tutorial
Traveling Waves Present on Most Line Phenomena
Closing into a fault, 500 kV field test data.
Page 29 Capacitor and Reactor Switching, J. H. Brunke, July 2008 Presented at IEEE Circuit Breaker Tutorial
Shunt Reactor Switching
1st Parallel 1 to 10 MHz
2nd parallel 50 to 1000 kHZ
Load oscillation 1 to 5 kHz
Page 30 Capacitor and Reactor Switching, J. H. Brunke, July 2008 Presented at IEEE Circuit Breaker Tutorial
225 Mvar Shunt Reactor Interruption
500 kV bus and reactor voltages, field test data
Page 31 Capacitor and Reactor Switching, J. H. Brunke, July 2008 Presented at IEEE Circuit Breaker Tutorial
Time Expansion of Previous Slide
Page 32 Capacitor and Reactor Switching, J. H. Brunke, July 2008 Presented at IEEE Circuit Breaker Tutorial
Re-ignition and Current Chopping
Page 33 Capacitor and Reactor Switching, J. H. Brunke, July 2008 Presented at IEEE Circuit Breaker Tutorial
Time Expansion of Previous Slide
Page 34 Capacitor and Reactor Switching, J. H. Brunke, July 2008 Presented at IEEE Circuit Breaker Tutorial
Reactor Current Interruption Failure
•Interruption still a difficult duty for circuit breakers
•Differences in the parameters make a standard test nearly impossible
Page 35 Capacitor and Reactor Switching, J. H. Brunke, July 2008 Presented at IEEE Circuit Breaker Tutorial
Shunt Reactor Current Interruption w/o Controlled Opening
Page 36 Capacitor and Reactor Switching, J. H. Brunke, July 2008 Presented at IEEE Circuit Breaker Tutorial
Shunt Reactor Current Interruption with Controlled Opening
Page 37 Capacitor and Reactor Switching, J. H. Brunke, July 2008 Presented at IEEE Circuit Breaker Tutorial
Energizing Shunt ReactorsInrush currents smaller than for power transformers (to be discussed
next), and not generally considered a problem
Can cause sympathetic inrush in nearby power transformers
Problems have only been observed in certain configurations
Page 38 Capacitor and Reactor Switching, J. H. Brunke, July 2008 Presented at IEEE Circuit Breaker Tutorial
Switching Transformer Magnetizing Currents
Page 39 Capacitor and Reactor Switching, J. H. Brunke, July 2008 Presented at IEEE Circuit Breaker Tutorial
Transformer Core Characteristic
Page 40 Capacitor and Reactor Switching, J. H. Brunke, July 2008 Presented at IEEE Circuit Breaker Tutorial
Magnetizing Current Interruption
Magnetizing current interruption also showing core flux
Residual core flux remains (typical pattern)
Page 41 Capacitor and Reactor Switching, J. H. Brunke, July 2008 Presented at IEEE Circuit Breaker Tutorial
Energizing a Transformer
Page 42 Capacitor and Reactor Switching, J. H. Brunke, July 2008 Presented at IEEE Circuit Breaker Tutorial
Inrush Current
Page 43 Capacitor and Reactor Switching, J. H. Brunke, July 2008 Presented at IEEE Circuit Breaker Tutorial
Controlled Closing Applied to Transformers
Page 44 Capacitor and Reactor Switching, J. H. Brunke, July 2008 Presented at IEEE Circuit Breaker Tutorial
Three Phase Transformers
Page 45 Capacitor and Reactor Switching, J. H. Brunke, July 2008 Presented at IEEE Circuit Breaker Tutorial
Prospective and Dynamic Flux
5 8 .05 4 .05 0 .04 6 .04 2 .0
T im e m s
F lu x , re s id u a l 0 % , -7 0 % , 7 0 %0 .8 0
0 .0
-0 .8 0
F lu x kV s
ACB
Page 46 Capacitor and Reactor Switching, J. H. Brunke, July 2008 Presented at IEEE Circuit Breaker Tutorial
Core Flux - No residual
Page 47 Capacitor and Reactor Switching, J. H. Brunke, July 2008 Presented at IEEE Circuit Breaker Tutorial
Core flux with residual flux
Time 6 ms/div
Core flux, EMTP Study 800
0.0
-800Vs
Page 48 Capacitor and Reactor Switching, J. H. Brunke, July 2008 Presented at IEEE Circuit Breaker Tutorial
Verification - Laboratory Tests Delayed Closing Strategy
T im e 6 m s /d iv
.8 0 0 0
0 .0
- .8 0 0 0V s
Page 49 Capacitor and Reactor Switching, J. H. Brunke, July 2008 Presented at IEEE Circuit Breaker Tutorial
Test on Laboratory Transformer
Page 50 Capacitor and Reactor Switching, J. H. Brunke, July 2008 Presented at IEEE Circuit Breaker Tutorial
Controlled Closing on 500 kV Transformer
Page 51 Capacitor and Reactor Switching, J. H. Brunke, July 2008 Presented at IEEE Circuit Breaker Tutorial
SummaryCapacitive and light reactive currents are frequently seen and may be
the most difficult duties for a circuit breakerSwitching surge/transient problems are typically associated with
switching shunt capacitor banks, shunt reactors, transformers, cables, and lines (capacitive and light reactive currents).
Due to the complexity, correct application for these duties can be among the most difficult application issuesToday solutions are available which were not in the past (modern circuit
breaker technologies, controlled switching, MOSA’s, etc.)
Questions?