Abstract: Abstract:In a substation, the line clamp terminal of the EHV transformer failed due to fracture. Mechanical property test, microstructure analysis, sample fracture analysis and finite element calculation for the clamp terminal were carried out. It was determined by the analysis results that there were defects in the clamp terminal material, which include the micro-pores, the casting shrinkage hole (or loose) and others. Meanwhile, the bolt pretightening force during the clamp terminal installation was too large. These caused the fracture failure of the clamp terminal. Some targeted improvement suggestions were given.

Key words: Keywords:extra high voltage (EHV) transmission, line clamp terminal, fracture failure, fracture analysis, finite element calculation