ABSTRACT
Circuit breakers are electromechanical devices used in the power system to connect or disconnect the power supply at the generator, substation, or load location. The circuit breaker consists of current-carrying contacts called electrodes. When the power is on, these electrodes are normally in contact and they will be apart when the power is disconnected. During the disconnection of the power supply, the contacts are separated and an arc is struck between them. The arc plays an important role in the interruption process by providing for the gradual transition from current-carrying to voltage-withstanding state of the contacts. Most of the technical problems in the circuit breaker are related to arc quenching and transient overvoltages across the circuit breaker blades in the open condition. The opening and closing of the circuit breakers in a capacitive circuit poses additional technical problems due to the energy stored in the capacitor elements.
