In this paper

in light of the contamination phenomenon of shunt capacitor between open contacts of 500 kV circuit breakers in certain substation

defect diagnosis of capacitor oil leakage is given through on-site investigation. Starting from the circuit model of circuit breaker with two breaks installed with shunt capacitor

the grading principle

improvement of capacitor to the electric filed distribution of open contacts as well as influence to dynamics of power system are analyzed. Therefore

it is concluded that existence of the defect will lead to three kinds of different power system accident and

at the same time

the treatment measures for the defects are proposed;finally

some attentions in the dielectric loss measurement of capacitor after replacement on-site is proposed from such three aspects as Garton effect

interference effect of inductive electric field and influence of RTV contamination resistance paint to dielectric loss measurement. The solution is given briefly

and the analysis has a definite reference.