Calculation of the Short-time Withstand Current for Air Circuit Breaker

Abstract

In the optimization design of contact system for the air circuit breaker (ACB), it is important to calculate the short-time withstand current. Introducing the contact bridges to describe contact spots between movable and fixed contacts, transient analysis is carried out by coupling electromagnetic field and thermal field to parallel contact systems, where nonlinear of ferromagnetic splitter plates and properties of conduct material varying with temperature are under consideration. In each time step of calculation, the cross-sectional areas of the contact bridges are changed with the contact forces by Holm formula. The proposed method could be used to analyze the short-time withstand current of ACB.