Thermal Requirements of Resistors used in Circuit Breakers for Transient Voltage Control

The thermal requirements of resistors used for power system transient voltage control are a function of the applied voltage, the resistor ohmic value, and insertion time. These energy requirements are discussed for resistors used in circuit breakers for closing and/or opening operations and also for repetitive duty cycles. The thermal design levels are derived from fault duty, line energizing, line reenergizing, and out-of-step conditions.