Testing of circuit breakers using coil current characteristics analysis

The paper presents the construction and principle of a designed system for diagnostic testing of high voltage circuit breakers (CB). The diagnostic testing system of circuit breakers is performed by characteristic analysis, and the discrete-time Mallet wavelet transform algorithm is used to process the signal of coil current. The coil current characteristic patterns from circuit breakers (made by ABB Corporation) are acquired, compared and analyzed. The circuit breakers are all tested under the conditions of working fields to ensure the objectivity of the conclusion. The accuracy and reliability of the system has been proved through an analysis of the test results. The serious faults on circuit breakers, including operating mechanism delays and major lubrication problems are detected correctly by the diagnosis system. Thus, the testing process and results performed under realistic conditions demonstrates that the coil current characteristic analysis is a reliable and feasible method for diagnostic testing on circuit breakers.