Cracking Analysis of a Brass Clamp Mounted on the Main Transformer in the Power Grid System

Abstract

Cracking of conductive brass accessories in substations causes overheating or an open circuit, seriously affecting the safe and stable operation of the power grid system. A deep understanding of failure mechanisms could provide more safety, as well as lower down costs and save time for the power grid system, which have been seldomly involved in the literature. This paper presents a cracking analysis of a brass clamp in service for seven years that is mounted on the main transformer. The fracture morphology, chemical composition, and metallographic structure of the brass clamp were systematically analyzed, and the stress conditions were obtained by finite element simulation. The clamp exhibits transgranular brittle fracture with high oxygen content in the fracture, containing a crack propagation along the Pb particle connecting pathways, and the stress concentration was confirmed at the crack position. It is concluded that the failure was a result of the stress corrosion cracking and excessive content of Pb. Suggestions were proposed to avoid malfunction of the main transformer caused by the clamp crack.

Effect of Wear on Vibration Amplitude and Chip Shape Characteristics during Machining of Eco-Friendly and Leaded Brass Alloys

“…Tool wear significantly affects these friction-induced nonlinear vibrations and can be observed through the vibration characteristics of new and worn cutting tools. The evolution of the vibration characteristics can be used for the tool wear progress monitoring, too [41][42][43].…”