Abstract: Air Circuit Breakers (ACBs) are popularly used for low voltage application in many industries and distribution panels. ACBs possess fault interruption capabilities such as high making and breaking capacity. ACB operates on the mechanism of sensing current through Static Release (SR) action which results in Free Return Charging Device (FRCD) being operated. The reliability greatly depends on the smooth mechanism operation of ACB. This paper illustrates root causes of various faults on ACB during its lifespan using Ishikawa diagram. ACB serves a vital part of the protection of power system, it’s reliability gains importance. The testing of ACB in the company is carried out as per International Electrotechnical Commission (IEC) codes using on field fault conditions which ensures its reliability in market as guaranteed by the organization. The industry carries out testing on test bench by creating on field fault condition such as overload, short circuit, earth fault which is based on the principle of primary and secondary injection methods. The reliability of ACB can be predicted by detailed analysis of testing results.

Keywords: Air Circuit Breaker, Free Return Charging Device, Microprocessor based Static Release

| DOI: 10.17148/IJIREEICE.2019.7202