Influence of High Altitude Environment on Electrical Performance of Miniature Circuit Breaker

In the high altitude environment, the electrical performance of the miniature circuit breaker will deteriorate. The influence of pressure on the external natural convection and internal breakdown field strength of the miniature circuit breaker was obtained through theoretical derivation in this paper. The thermocouple model and the electric field model were established. Combined with simulation and theoretical calculation, it was obtained that the temperature rise of the miniature circuit breaker at an altitude of 4300m rise by more than 12K and the air breakdown field strength drop by 36.8% compared to that in the plain area. At the same time, the temperature rise test and dielectric test were carried out in the high altitude area and the plain area. The simulation conclusion was verified by the test result.