Corrosion Failure Analysis of Fittings Used for Electrical Equipment in 220 kV Substation

Abstract

Abstract Electric power fitting is a metal accessory that connects and combines different devices in the electric power system, and transfers mechanical load and electrical load. Once the fitting fails, it would lead to large-scale blackout, so its reliability is of great importance for the security and stability of power system. In this paper, the seriously corroded electric power fitting in 220kV substation was investigated by means of macro-morphology inspection, chemical composition analysis, microstructure analysis, scanning electron microscope, zinc coating thickness measurement and energy spectrum analysis. The result showed that sulfur dioxide emitted from industrial production was the main cause of corrosion failure of the fitting. Meanwhile, the insufficient corrosion resistance of the fittings led to acceleration of corrosion process and premature failure of zinc coating. Additionally, effective suggestions were put forward in order to improve the anti-corrosion performance of the fittings in typical industrial pollution area.