Thermal-Pressure Effect Simulation and Protection Effect Analysis of Metal Grid Absorber Due to Internal Short-Circuit Arcing in the Switchgear

Abstract

As one of the important pieces of equipment in the power system, the safe and stable operation of switchgear is crucial to the security and reliability of the power supply . However, short-circuit arcing accident in the switchgear happens occasionally, the high temperature and pressure effect produced by which seriously threatens the safety of surrounding buildings and staff. In this paper, a calculation method of arc thermal-pressure effect based on arc energy heat equivalence was proposed, and the validity of the calculation method was verified by experiments . Meanwhile, in order to reduce the harm of high temperature and high-speed airflow caused by short-circuit arcing process, the protective measures based on metal grid absorber were put forward. An equivalent mathematical model of metal grid absorber was constructed, and the influence of grid arrangement on the protection effect was analyzed. The results show that the pressure rise obtained by the arc energy heat equivalent method is in good agreement with the experimental results, and the error is small. The metal grid absorber can effectively reduce the temperature and velocity of gas in the opening. When the metal grid absorber is in-line arrangement, the maximum velocity and temperature of gas in the pressure relief opening are decreased by about 31.18% and 38.29%, respectively. The protection effect of the metal grid absorber with staggered arrangement is better, and the heat absorption efficiency is about 6.83%, which is about 2.09% higher than that of metal grid absorber with in-line arrangement.