关键词: SF₆气体绝缘, 断路器, 瓷套管, 机械强度, “V”形接口

Abstract: The porcelain bushing above 2.5m is usually fired in sections, and the cross-section is mechanically treated to form a “V” shaped interface. Then, the upper, middle and lower single sections are integrally fired and connected with inorganic adhesive glaze at high temperature. The adhesive glaze and each section of the porcelain bushing melt and penetrate into each other to form a whole porcelain bushing. After the overall firing is completed, its mechanical and electromechanical properties shall be verified by visual inspection, dimensional inspection, ultrasonic flaw detection, high and low temperature cycle test, internal pressure load test and bending load test. This paper analyzes the reasons for the breaking (bursting) of the sectioned porcelain bushing of 500kV SF₆ circuit breaker, comprehensively analyzes and demonstrates various factors affecting the electromechanical performance of the porcelain bushing of SF₆ tank circuit breaker through the disassembly inspection and test detection of the porcelain bushing, and puts forward strategies and measures to improve the process quality of the porcelain bushing and ensure the performance of the porcelain bushing, which provides references for the scientific design and safe operation of SF₆ tank circuit breaker.

Key words: SF₆ gas insulation, circuit breaker, ceramic sleeve, mechanical strength, V-shaped interface