Because the change of tripping/closing coil current（CC）and the vibration signal can reflect the run-ning state of an operating mechanism

a new method based on multiple parameters is presented for fault diagno-sis of tripping/closing coil of the high-voltage circuit breakers（HVCBs）and for improving the accuracy of the fault diagnosis. First

the operation state of the actuator electromagnet is introduced

and the relationship be-tween the signals and the operating states of the actuator is analyzed. Second

a hardware circuit taking the NI data acquisition card and the real-time controller as the core is designed. Third

the multi-layer wavelet packet（WP）decomposition and reconstruction algorithm is used to filter the signals

and the extreme value method is used to extract the eigen-values. Finally

the particle swarm optimization（PSO）method is combined with the support vector machine（SVM）to classify the states of HVCBs. Experimental results show that the present algo-rithm can detect the hidden failure of HVCBs in operation and improve their reliability.