This 3-day advanced course covers the origin and derivation of the transient recovery voltage (TRV) requirements for circuit breakers applied for fault clearing and the switching of inductive and capacitive loads. The course first develops the fundamental concepts involved in current making and breaking including oscillatory circuits, pole factors, and travelling waves. The developed concepts are then applied to the individual current interruption case TRVs and associated reignitions or restrikes and to making and breaking capacitive and inductive circuits. All cases are well illustrated by real examples. At the end of the course, attendees will have an in-depth knowledge and understanding of the TRV requirements in IEC and IEEE standards and also know how to deal with exceptional cases.
- Fundamental basis for TRVs and reignition and restriking transients,
- Generic approach to the calculation of TRVs and reignition and restriking transients,
- Derivation of pole factors and amplitude factors associated with TRVs as specified in IEC 62271-100 and IEEE C37 Series,
- Calculation of the effects of adding surge capacitors to control TRVs; effect of shunt capacitor banks, series reactors and opening resistors, AND
- Calculation of TRVs and reignition and restriking transients associated with inductive and capacitive loads, respectively.
To benefit from the course attendees should have a basic prior knowledge of the following:
- Electric circuit theory,
- Differential equations,
- Trigonometric and exponential functions,
- Symmetrical components,
- IEC Standards 62271-100 and 62271 110 or IEEE C37 Series, and
- Use of Excel for equation based calculations.
- Overview and definitions, and
- Basic principles of current interruption in circuit breakers.
- General approach to series and parallel RLC oscillatory circuits,
- Underdamping, critical damping and overdamping,
- Damping factors, and
- Amplitude factors.
Pole Factor Calculation
- Basic theory and general approach to using symmetrical components,
- Balanced and unbalanced fault calculations,
- AC recovery voltage calculations, and
- First, second, and third pole factor calculation.
- Basic concepts,
- Steady state waves, and
- Open circuit and short circuit termination cases.
- Circuit breaker rating basis,
- Four parameter and two parameter TRVs,
- Standard circuit for TRV derivation,
- 100% and 60% terminal faults,
- 30% and 10% terminal faults,
- Effect of shunt capacitor banks, series reactors, and opening resistors,
- Double earth faults, and
- Asymmetrical fault currents.
Short Line Faults
- Line side travelling waves, and
- TRV calculation.
Inductive Load Switching
- Shunt reactor switching, and
- Unloaded transformer switching.
Capacitive Load Switching
- Shunt capacitor bank switching,
- Unloaded transmission line switching, and
- Unloaded cable switching.
Generator Circuit Breaker TRVs
- System-source faults,
- Generator-source faults,
- Out-of-phase switching,
- High-side faults, and
- Load current switching.
Principlal, DF Peelo & Associates Ltd.
Dr. David Peelo, consultant and former switching specialist at BC Hydro; active Cigre member; past Convenor IEC MT32 (Inductive load switching), IEC PT42 (Capacitive current interrupting capability of air break disconnectors), and member IEC MT57 (Application guide for IEC 62271 100 and other circuit breaker related standards). He is an IEC 1906 Award recipient, a Distinguished Member of Cigre and the author of a textbook on current interruption transients calculation and the co author of a textbook on switching in T&D networks and a Cigre SC A3 Green Book on switching equipment.