High voltage circuit breaker is one of the most important electrical apparatuses and the opening/closingcoil is a key component of its operating system. In recent years

the fault of the opening/closing coil has occurred

which seriously affects the safety performance of the power system. In this paper

the loop structure and action princi-ple of a high voltage circuit breaker’s opening/closing coil is studied

the simulation prototype of the circuit breakermechanism is designed

and a test platform for collecting the current of the circuit breaker is set up. Based on thewhole platform

opening/closing coil current is collected both in normal and abnormal conditions. After that

the char-acteristic parameters of current curves were extracted and the parameters of those curves was analysed. It can be con-cluded that characteristic parameters of opening/closing coil current will changed obviously when devices have mal-functions. The work of this paper provided test basis for fault diagnosis.