On-Line Monitoring And Fault Diagnosis Of Shunt Release

The circuit breaker is one of the indispensable electrical equipment to guarantee the reliable and stable operation of power system,and its reliability directly affects the performance of the power system.Shunt release is one of the most important accessories of circuit breaker,its healthy state directly determines whether circuit breaker is reliable.Shunt release has frequent operations,which is more likely to happen mechanical and electrical faults,therefore,the paper chooses shunt release as the main study subject.In this paper,the measure of condition monitoring for shunt release of circuit breaker is put forward for the limitations of existing inspection methods and technical development trend,and the main research is listed as below.1?The working principle and fault type of shunt release are mentioned,and the modeling of shunt release is modeled by the SolidWorks software.The software of ANSYS Maxwell is used as the simulation platform,establishing the simulation model of three-dimensional transient field of shunt release based on the finite element analysis theory.The validity of the simulation model is verified by comparing the actual and simulated coil current and displacement curve.The simulation model is used to simulate the different stress conditions of shunt release,and study preliminarily on the relationship between current waveform and mechanism state.2?In order to further study the relationship between current waveform and mechanism state,the overall scheme of on-line monitoring of shunt release is proposed,and the hardware structure and corresponding software of each function module is designed.3?For the fault condition of the shunt tripping device,two cases need to consider.On the one hand,when the coil of shunt release isn't energized,the small signal injection method is proposed to extract the static characteristics of the resistance and inductance of the coil,and the accuracy and effectiveness of the method are verified by the experiments.On the other hand,when the coil is energized,the changes of coil current waveform of different state of shunt release are analyzed,and the method of wavelet packet decomposition to extract the signal dynamic characteristics is proposed.Through the comparison of each component of the wavelet,the time of extreme value in scale component of optimal decomposition level is selected as the characteristic quantity.Comparison of wavelet components with different force and stroke situations,the characteristic quantity of shunt release is validated.4.The fault diagnostic expert system is introduced to researching on the connection between all kinds of characteristic quantity and the states of health of shunt release,and establishing the regular knowledge base.The experimental results show that this method can effectively and accurately determine the health status of shunt release.In this paper,a new type of on-line monitoring technology of shunt release of circuit breaker is proposed,which provides a new theoretical idea and solution for reliability and intelligence level of the circuit breaker.The established three dimensional simulation model could deeply study the relationship between the coil current waveform and the different health status of shunt release,which provides the theoretical basis for further research.The designed on-line monitoring device could provide data basis and verification platform for the validity and reliability of all kinds of characteristic quantity and comprehensive judgment result of health state of shunt release.