Condition assessment of high voltage circuit breaker is an important approach to providing decision-making for condition maintenance and improving operation reliability of power systems. In this paper

an integrated condition assessment model of high voltage circuit breaker is established based on the matter-element extension and evidence theories. The matter-element analysis is performed for the condition assessment

then the correlation functions of the assessment indicators are constructed

and the values of the correlation functions are calculated. When the indicators are in normal state

the correlation function values are positive

while when the indicators are in abnormal state

the correlation function values are negative. The degree dependency of the assessment indicators is obtained by applying set-pair analysis to deal with the initial uncertainty state of the assessment indicators

and it is amended as basic probability assignment function. The ultimate assessment results are obtained by merging the basic probability assignments based on modified evidence theory. Test data verify that the proposed model is feasible

and the degradation degree of each assessment indicator can be determined. This study may provide a new line of thought for condition assessment of high voltage circuit breakers.