As researches on risk assessment of power equipment is developing

it remains several issues

such as the assessment features of different types of evaluation objects are not universal

traditional assessment methods are vulnerable to human factors and can’t distinguish between the importance of each indicator. Based on the fault tree of the condition assessment guidelines of transformers

circuit breakers and other main equipment

combined with field operational data and failure distribution

the article proposes failure probability assessment method derived from the membership function

the relative degree of degradation and weighted average. In this article

it also introduces fuzzy analytic hierarchy process to determinethe relative weights of end events and intermediate events

to realize the risk assessment of any equipment components. Finally

it analyzes the risk assessment index of No.3 transformer in a 500 kV substation

verifies the evaluation model

and proves the feasibility and effectiveness of the model according to the actual operation and maintenance situation. The risk assessment program proposed in this article overcomes the disadvantage of subjectivity

making its evaluation results more objective. Thus it could be applied in EHV of China Southern Power Grid Company.