Cause Analysis and Preventive Measures of Abnormal 750 kV Arrester

This paper describes the abnormal heating of the metal oxide arrester at the high voltage side of 750 kV main transformer. Infrared temperature measurement, insulation resistance and capacitance test data were used to preliminarily determine the cause of abnormal heating. It was found that the upper four sections and the lower two sections of the arrester were installed reversely through disassembly inspection. At the same time, it was clear that the installation error would cause the uneven distribution of the arrester potential to increase by calculation and verification, leading to the increase of the charging rate and power loss of the arrester resistor, resulting in temperature abnormality. In addition, the applicability of the test analysis method for the abnormal heating of the arrester is analyzed and the preventive measures are proposed.