Study On Time Scatter Of Vacuum Circuit Breaker With Hybrid Mechanism

In recent years,with the overall goal of the State Grid Corporation to build a "reasonable structure,technologically advanced,safe,reliable,intelligent and efficient distribution network".The intelligent distribution networks have become a major part of today’s power system construction.With the rapid development of intelligent distribution networks,switchgear not only meets the conventional opening and closing requirements,but also has a large number of special application requirements for flexible control and protection.These needs can be met by phase-controlled switching technology.But phase-controlled switching technology requires that the switch open and close as fast as possible and the dispersion of the operating time is small enough.At this stage,the inherent stability and speed of the circuit breaker itself can already meet the requirements of phase-controlled switching technology,but the operation time of the circuit breaker is still affected by various factors.The study of circuit breaker dispersion is still a key issue in phase-controlled switching technology.In this paper,we focus on studying the variation law of operation time with the influencing factors such as ambient temperature,capacitance voltage,capacitance degradation,mechanical wear and tear and pre-breakdown voltage based on the permanent magnet-repulsion hybrid mechanism for fast switching,and finally compensate for the above influencing factors.At first,we study on the mechanism of the influence of each factor on the operation time of the hybrid mechanism.Then the electromagnetic field modeling and simulation of the hybrid mechanism used in this paper is carried out to analyze the rapidity and advantages of the hybrid mechanism used in this paper using double-coil parallel permanent magnet closing and double-coil disc repulsion dividing.While the range of electrical parameters of the hybrid mechanism is determined in order to reduce the sensitivity of the fast switch to the influence of each factor.The variation law of the hybrid mechanism with ambient temperature,capacitance voltage and capacitance capacity is simulated by specific test data.The effects of mechanical wear and pre-breakdown voltage are analyzed by means of mathematical models.On the basis of the theory and simulation,a test circuit is built and a test model is constructed using a 10 k V fast switching test prototype.The effects of temperature and capacitance voltage on the operation time of the hybrid mechanism,the effect of capacitance capacity change on the operation time of the hybrid mechanism,the effect of frequency of hybrid mechanism operation on capacitance capacity and internal resistance,the relationship between mechanical wear and frequency of operation,and the relationship between pre-breakdown voltage and contact spacing are studied by the control variable method.The influence law is determined by comparing the test data with the theoretical and simulation analysis of each influencing factor.The experimental and simulation data are organized and analyzed to form a database.The GRNN neural network has excellent prediction,self-learning,nonlinear mapping and good tolerance ability.The accuracy of the fast switching phase selection control is improved by using the GRNN algorithm to complete the fast switching feedforward time compensation scheme.