Analysis on the Breaking Reason of Crank Arm of Switching Transmission Mechanism of 500kV Porcelain Circuit Breaker
Author of the article:ZHANG Hongwu;FENG Nannan;LIU Rui;CHEN Yang
Author's Workplace：Shandong Electric Power Industry Boiler and Pressure Vessel Inspection Center Co.,Ltd.,Jinan 250003,China;Jinan Jingwei Electric Power Engineering Consulting Co.,Ltd.,Jinan 250021,China
Key Words：converter station transmission mechanism crank arm high content of impurity elements poor casting process fracture metal supervision
Abstract：
The arm of the switching mechanism of 500 kV porcelain column circuit breaker in the AC filter field of a converter station was broken.The fracture reasons were analyzed by the macroscopic and microscopic morphology and energy spectrum analysis and the tensile mechanical properties and Brinell hardness test of the arm.The results show that the fracture is caused by low purity of raw pig iron,high content of impurity elements,poor casting process,large number of casting defects,and poor mechanical properties,which could not meet the requirements of long-term operation.In order to avoid similar accidents,it is suggested to strengthen supervision and strictly control the quality of equipment.
