Research On Fault Mechanism And Diagnosis Method Of Circuit Breaker Spring Operating Mechanism

High voltage circuit breakers are used widely in the power plants and substations,they can protect and control the transmission lines.Spring operating mechanism provides power for the high voltage circuit breaker to open and close.Mechanical failure may occur during the operation,such as jamming and refusal,also the faults take up a big proportion in the all faults.Therefore,it is of great significance to carry out the research on high voltage circuit breaker failure,which can ensure the safety and stability of the power system.In this paper,the spring operating mechanism of circuit breaker was taken as the research object,and the research on fault mechanism,time characteristic parameter extraction and diagnosis method was carried out.The main contents are as follows:(1)Fault simulation and experimental analysis was conducted on the circuit breaker spring operating mechanism.First,the circuit breaker model was established according to the mechanical drawings.Then,through adjusting the corresponding parameters in ADAMS,the movement of spring operating mechanism in the normal state,closing spring fault,buffer spring invalid and actuator fault was simulated,the change rule of closing speed and maximum travel of circuit breaker moving contact was obtained.Taking LW42A-40.5 circuit breaker as research object,the change rule of moving contacts in normal and fault conditions are measured respectively.which can verify the correctness of the simulated results.(2)A new method for extracting circuit breaker time characteristic parameter from vibration signal was proposed,which can solve the problem that the traditional method can only be carried out under the condition that the circuit breaker is powered off,and cannot be measured online.Through the selection and correlation analysis of the vibration measuring points on circuit breaker,the one-to-one correspondence between the time characteristic parameters and the vibration signal was combed The VMD denoising method and the double threshold method based on short time energy entropy ratio were adopted to extract the time characteristic parameters during the opening process and the closing process from the multi-path vibration signal.The experimental results show that the measurement error was within the allowable range.This study provided a new method for online detection of high voltage circuit breaker time characteristic parameters.(3)The time parameter of vibration event are used as feature vector to diagnose the fault type of high voltage circuit breaker,which achieved good classification and recognition results.After comparing and analyzing the vibration signals in different operating conditions of the circuit breaker,it was found that the occurrence time and end time of the vibration event were different in different operating conditions.Then,select the time parameter of the representative vibration event as the feature vector,which can represent the change of fault characteristics of the circuit breaker under different operating conditions.For the constructed time feature vector,fuzzy C-means clustering was used to train the feature vector,and the clustering center was obtained,and the test samples are classified according to the principle of closeness.The classification results showed that the proposed feature vector has clear physical meaning and good diagnostic effect.(4)A fault diagnosis method for circuit breaker based on multi-dimensional feature vector of vibration signals was proposed.By comparing different decomposition algorithms,it was found that VMD has advantages in signal preprocessing.After using different entropy set algorithms to characterize the change rule of vibration signal,the superiority of VMD-MSN feature vector was verified.On this basis,the fault diagnosis method based on multi-dimensional feature vector of vibration signals was proposed.The multi-dimensional feature vector can characterize the vibration signal from time and energy,and good classfication result was obtained by using SVM to train and classify the proposed feature vector.This research provides a new method for fault diagnosis of circuit breakers.(5)After theoretical research,a set of condition monitoring and fault diagnosis system for high voltage circuit breaker was developed based on C#language,the composition of software system and hardware system is given.The developed software system functions include information management,data acquisition,historical data and fault diagnosis.The development platform,organizational structure and workflow of the software system were studied.The functional flow chart and software interface of each sub-module in the software system were designed.The developed system has greatly practicality and popularization value.