In order to solve the problem of quantitative description and effective monitor of the defect development of trip device in high voltage circuit breaker

an online state parameter estimation method of trip device based on covariance matrix adaptive evolutionary strategy (CMA-ES) is proposed in this paper. By estimating the three key parameters

including coil resistance

core resistance

and electromagnet space

the defect identification and the monitor of defect development in the trip device are realized. Firstly

a mathematical model of the trip device is established and verified by experiments

which provides support for the parametric characterization of the defect state and the construction of the fitness function used in the parameter estimation problem. Then

by using the short-time energy of the vibration signal and the sliding window adaptive threshold method

the coil current of the electromagnet during the gap movement stage is extracted as an effective input to the parameter estimation problem. Finally

the CMA-ES method is used to search the parameter space efficiently and determine the optimal state parameter vector that makes the fitness function get the maximum value. The results of multi-condition experiments show that the maximum estimation error of the three state parameters is less than 7.1%. The method proposed in this paper is helpful to quantitatively monitor the development process of defects and promote the realization of effective warning of the rejection risk.