| The circuit breaker plays an important role in the power transmission and distribution system.Its running state directly affects the stability and reliability of power system.The circuit breaker mechanical characteristic tester can accurately test the mechanical characteristics of the circuit breaker,so as to reduce the equipment failure rate and improve the service life of the circuit breaker.In this paper,based on the characteristics and development trend of the circuit breaker test program at home and abroad,a portable circuit breaker mechanical characteristic tester is developed.However,the general characteristics of the circuit breaker tester mostly use the combination of the acquisition card and the host computer,with the disadvantages of high cost and large size.The system improves the portability and practicability of the circuit breaker characteristic test,and has important application value.First described the definition of mechanical characteristic of vacuum breaker and the influence on the performance of the circuit breaker,and to determine the relevant parameters measurement method.The principle and characteristics of the sensors used in the market are compared and analyzed.Finally,the GSM010 GT Holzer current sensor and the TS-0050 linear displacement sensor are used to test the coil current signal and the moving contact travel signal respectively.On this basis,a system design scheme of circuit breaker mechanical characteristic tester based on DSP is put forward.This scheme takes TMS320F28335 as the core,16 bit AD7606 sampling chip,the test parameters including on-off coil current,the moving contact travel,contact state,can achieve synchronous acquisition,parameters calculation,LCD240128 display,SD card storage.In the process of signal acquisition,there are various kinds of noise interference.In this paper,wavelet threshold de-noising is used to preprocess the signal.Through the experimental comparison and analysis,the Db4 wavelet base is determined,the decomposition level is 4,and the optimal denoising method of Rigrsure threshold strategy is proposed,and the feasibility of the method is verified by MATLAB.Then extract the feature value of closing coil current signal,and lay the foundation for fault diagnosis.Finally,the experimental platform is built in the laboratory,the ABB VD4 vacuum circuit breaker is tested,and the test results of the GYT-07 mechanical characteristics tester are compared to verify the accuracy of the test system.The experimental results show that the error of the mechanical characteristic parameters such as the peak current of the coil,the closing / opening time,the travel distance of the contact,the opening and the closing speed are less than 3%,and the test precision is high which can meet the requirement. |
