To Improve Thermal Performance of Air Circuit Breaker

Abstract

Air circuit breaker is a switching device which is used to make and carry current under normal con- dition and breaking current under abnormal condition. In normal condition when circuit breaker is ON, due to current owing in the circuit, heat is generated due to ohmic losses. The generated heat needs to be dissipated properly. If the generated heat is not properly dissipated, then it can lead to increase in temperature of the components of air circuit breaker. This continuous increase in temperature in longer run can violated thermal limit and damage insulation which can ultimately lead to thermal breakdown and flashover in the air circuit breaker. The ash over can lead to loss in properly, production and human injuries in some cases. IEC standard has recommended temperature limit for defined current rating but deviation to use suggested different techniques for maintain thermal limit was observed at customer end to reduce cost impact. The aim of this project is to study the thermal performance of complete current path of Air circuit breaker. Based on the study, improvement needs to be proposed in the thermal performance of air circuit breaker and to keep the temperature within threshold limit for safety of equipment.