So it happens easily that some causes are missed during fault diagnosis which is called cause-missed problem in this paper.

Through to Shuozhou area seven mile ditch 220 transformer substation 2# the transformer oil chromatograph track analysis and the DC resistance test,the overall has judged the breakdown reason,introduced the treating processes,and aimed at this example breakdown to propose the related lead wire aspect conclusion.

The process,fault reason arousing monitor system s repeated and automatic quit by the primary equipment s power failures are demonstrated.

According to this problem,this paper puts forward energy method to analyze the fault reason of hydraulic system heat,so as to get exact fault diagnose method.

The fault causes and preventive measures of SF_6 current transformer;

This paper introduces the operation situation of 500 kV shunt reactors in North China Power Grid,analyzes their fault cause and presents the proposition for processing the fault reactors.

Based on the failure data of a computer numerical control (CNC) system in one and a half year, the failure positions and failure causes of the CNC system were analyzed.

The failure reasons are analysed and the preventing measures are proposed.