ABSTRACT
This chapter provides the basic principles and theory of circuit-breaker techniques. Circuit breakers, which have the function of opening and closing a circuit, are indispensable for protecting other transmission devices in a power system. When a short-circuit fault occurs, they quickly eliminate the fault to secure system stability. Performance requirements for circuit breakers also include high-speed interruption, ensuring power system stability, high-speed closing, and suppression of switching surge, particularly for ultrahigh-voltage systems. In power circuit breakers, the intensity of the current that flows through the conductors and the voltage level that must be sustained by the insulating material are very high, and at present the only practical approach may be the use of arc plasma. Present commercial circuit breakers resort to plasma temperature control as the basis for their function. The chapter also provides basic information on characteristics of power circuit breaker arc space, arc extinction—the conversion from plasma to insulating space—and information on insulating space characteristics.
