Arc phenomena and method of arc extinction in air circuit breaker

Abstract

Air Circuit Breaker (ACB) is an electric control devicethat interrupts the abnormal currents which result from theover-loads or short-circuits in Low voltage(less than1,000Vac or 1,500Vdc) distribution line. Recently, highercurrent breaking performance has become crucial inproviding the reliability for the modern devices requiringsmall scale and high performance. When ACB opens, inorder to isolate a fault no matter whether it is arcing faultor short circuit fault, an arc exist between the contacts.Immediately after the interruption, arc reignition canoccur, thus causing failure of interruption. Thereforediscontinuity of power supply is prolonged in this way.Therefore correct knowledge of microscopic processesthat can initiate and extinguish an arc is of greatimportance for reliability and quality of power in powersystems. An understanding of the interruption and reignition of an arc discharge has obvious significance forthe design and development of a wide variety of industrialdevices.[1]. When a short circuit occurs, a fault currentflows between the contacts of ACB even though they areseparated by the protective control system until ACBbreaks the fault current. In terms of arc extinguishing,ACB should generate as high an arc voltage as possibleduring breaking phase. The arc resistance (high arcvoltage) could lead the main circuit to zero arc current sothat arc plasma is eliminated.