Fault Mechanism Analysis And Life Assessment Of High Voltage Circuit Breakers

High voltage circuit breakers(HVCBs),which has the ability of switching loads and breaking off faults,have become one of the kernel power equipment in power transmission and transformation network.Therefore,the health of HVCBs and their effective maintenance are closely related to the reliability of the operation of the whole power grid.In this paper,the fault mechanism of HVCB is studied as a breakthrough point and the occurrence and development trend of mechanical faults are analyzed.Meanwhile,accurate diagnosis of defect type and defect degree is realized,the life of HVCB is predicted and fingerprint database is constructed based on valuable data.The detailed research contents are as follows:Above all,the mechanism of HVCB fault generation and development is studied and a comprehensive research method based on a failure mechanism analysis,which combined with fault tree and fault mode,mechanism and effect analysis,and criticality analysis quantitative analysis as the evaluation criterion of fault severity is proposed.Furthermore,based on the relevant statistical data,the mechanism of fault generation and development of HVCBs is analyzed.Meanwhile,the weak links of are located and the improvement suggestions are put forward.A fault simulation experiment is designed and part of weak links are chosen to be the object.As a result,the trend of fault generation and development based on the current of switching coil is analyzed,which provides multiple preparations for theoretical analysis and original data collection for further research.Secondly,pre-diagnosis and judgment of state trend of HVCB is studied and a comprehensive common defect types and severity of circuit breaker spring actuator diagnosis method is proposed.It follows the steps of selection of monitoring signals,feature extraction,purification and optimization of feature data and predictive diagnosis.Finally,the feasibility of this method is verified based on the data obtained from the fault simulation experiments.Thirdly,aiming at the problem of how to determine whether the old HVCBs still hold the use value,a life evaluation method of HVCB based on analytic hierarchy process and health index is applied.Firstly,the weight determination method of each parameter affecting the health level of HVCB is studied by analytic hierarchy process.Then,a life prediction model of HVCB based on health index is constructed by using stochastic fuzzy theory.Among that,the health level of circuit breaker is quantified and the estimation of the service life of the equipment is realized at the same time.At last,the validity of this method is proved by the calculation of circuit breaker history data.At last,a family fingerprint database system for current waveform of HVCBs switching coil is designed with the help of experiments and information recorded by factory.Simultaneously,the ideas of intelligent diagnosis technology and on-line monitoring of HVCBs are combined in the new system as well.The functions of the system include displaying the switching status,classifying and querying historical data and online analysis,etc.intensive management of multiple data aggregation is realized and valuable historical redundant data and experimental data are utilized and stored.In conclusion,a design prototype for the engineering application of comprehensive large data fault diagnosis and analysis of electrical equipment in the future is provided.