Design Optimization to Secure Multiple Arcing Time Interruption Performance of Self-Blast Gas Circuit Breakers

Recently, the focus has been on the development of self-blast gas circuit breakers with low operating force and compact design. The self-blast gas circuit breaker uses the high-temperature energy from the arc to nozzle ablation and increase the pressure in the heating chamber. In order to predict the interruption performance of a developed product, heat gas flow analysis is essential and must be accompanied by judgment criteria according to test type. In this paper, based on short line fault (SLF) test data of a 170kV 50kA 60Hz self-blast gas circuit breaker, the interrption performance index for each arcing time is derived and the critical point is secured. The index is calculated based on the pressure rise and heat gas emissions that are important for interrpution performance, and a design plan that satisfies interrpution performance at all arcing times is presented step by step. Depending on the process, a design that can satisfy interrpution performance at all arcing times is derived. Reliability is secured by comparing the analysis results and blocking performance indices of the proposed candidates and the reference model and verifying them through testing. © The Korean Institute of Electrical Engineers.