Analysis on the Reasons of 500kV High-Voltage Disconnectors Hoop Fracture

Abstract

The fracture reasons of 500kV high-voltage disconnectors hoops were analyzed. The fracture appearance, composition of chemical elements, metallographic, mechanical properties of the fractured hoops were investigated by ICP-AES, SEM, optical microscope, brinell hardness tester, universal testing machine. The test results that one reason is substandard products of this batch hoop. The composition of chemical elements and mechanical properties is fails to comply with applicable standards prescribed and the casting defects are found. Another reason is that the large pre-tightening force and tightens reverse order.