The Study On State Evaluation Method Of Vacuum Circuit Breaker Motion Characteristic With Permanent Magnetic Operating Mechanism

With the construction of smart grid in China and the needs of power equipmentcondition based maintenance technology, it increasingly requests for intelligent andreliability of high voltage vacuum circuit breaker. It can provide direction ofimprovement for manufacturing firms and basis of drawing up maintenance strategy inelectric power department by evaluating operating states of circuit breaker scientificallyand roundly.This paper works on solving the problems exist in state evaluation method ofvacuum circuit breaker, such as single signal diagnosis, low accuracy of evaluate results,lack of theoretical basis for the evaluation criterion and data unreliable of source. In thepaper, it has taken ZW45-12vacuum circuit breaker with mono-stable permanentmagnetic mechanism as an example, it has intense study on methods of state evaluation,fault diagnosis and signal processing, as well as on practical application, and the mainresearch content and result are as follows:It has been proposed the state evaluation method of circuit breaker motioncharacteristic based on multi-agent, designed the architecture in multi-agent system andevaluation process of this method; researched on mathematical model for distinguishbetween operating mechanism electrical characteristic fault and circuit breakermechanical characteristic fault. According to mechanical vibration signal, it has beenproposed the diagnosis method based on relevance vector machine theory for circuitbreaker mechanical characteristic; According to contact displacement signal, it has beenproposed the evaluation method based on extension theory for circuit breaker motioncharacteristic; and proposed the evaluation strategies of evaluation before diagnosis. Themethod can evaluation the current state and trends of the circuit breaker motion characteristic, work out the specific impact condition, overcome the influence ofindividual sensor failure on the evaluation results.It has researched on feature extraction method of contact displacement signal,operating mechanism current signal of circuit breaker; According to mechanical vibrationsignal of circuit breaker, it has researched on three time-frequency domain signalprocessing methods of the short time Fourier transform, wavelet packet energy entropy,Hilbert-Huang transform, adopting the fuzzy C clustering analysis algorithm to compareperformance of three kinds of feature extraction methods, in order to propose themathematical model of feature extraction agent reasoning machine based on mechanicalvibration signal; It has researched on the stability of feature data, and failure mechanismof circuit breaker, it has been proved that the reliability of data acquisition system and thefeasibility of feature extraction method, and obtained the change rule of each motioncharacteristic signal eigenvalue under different status of circuit breaker.It has been constructed the virtual prototype model of circuit breaker motioncharacteristic through the software integrated technique, calculated static retention,system reaction, equivalent mass and contact arc of the this model, signed the concretemodeling parameters. According to the measured signal data, it has checked the accuracyof the virtual prototype model established. Through comprehensive analysis of simulationdata of virtual prototype model and experimental data, it has calculated the parameterscriterion of circuit breaker contact displacement signal, and established the faultknowledge base of operating mechanism current signal.It has been designed and explored data acquisition system and evaluation system ofcircuit breaker based on multi-agent; proposed the design and implementation scheme ofsystem hardware and software, and ensured the reliability of the data acquisition system.Acquisition and evaluation system have been applied for national invention patent.Through experiments in five conditions: normal condition of circuit breaker, resistanceincreases of operating mechanism control loop, opening spring single take off,mechanism unsmooth of operating and transmission, and displacement sensor fault, it has been tested and verified that the accuracy of state evaluation method and theeffectiveness of evaluation system of circuit breaker motion characteristic.