Research And Application Of KYN Series High-voltage Switchgear Vacuum Circuit Breaker Operation Status Diagnosis Technology

The condition assessment of power equipment is the foundation of condition based maintenance and risk prediction of power grid operation.The KYN series switchgear undertakes the dual functions of protection and control for the medium voltage distribution network,and its safe and stable operation directly affects the reliability of power supply.However,the long-term operation of electrical components inside the switchgear in high current,high voltage,and strong electromagnetic field environments results in a diversity of switchgear faults during operation;As a core device,vacuum circuit breakers,once their operating characteristics deviate from the allowable range,will directly affect the safety and stability of the overall operation of the switchgear.Therefore,how to use online monitoring technology to diagnose and predict the operating status of KYN series high-voltage switchgear vacuum circuit breakers is a hot technical research topic that scholars cannot avoid.In the actual operation of KYN series high-voltage switchgear vacuum circuit breakers,common faults include reduced vacuum degree of the vacuum bubble,energy storage circuit failure of the spring operating mechanism,asynchronous opening and closing,and high contact temperature.At present,domestic and foreign scholars mainly focus on the diagnosis technology of the operating status of KYN series high-voltage switchgear vacuum circuit breakers based on their four major characteristics: vacuum,mechanical,electrical,and temperature.Due to limitations in experimental conditions,algorithm applications,and research depth,various traditional methods for diagnosing the operating status of vacuum circuit breakers are not perfect,or are difficult to implement and costly to apply in practical engineering,or have low detection accuracy and cannot accurately perceive fault status.Therefore,further research is needed on the operation status diagnosis technology of KYN series high-voltage switchgear vacuum circuit breakers to ensure the safe operation of KYN series switchgear.This article takes the ZN63A-12/3150-40 vacuum circuit breaker,which is matched with KYN28A-12/T3150-40 switchgear,as the research object.Corresponding algorithms are introduced from three aspects: mechanical characteristic fault diagnosis,temperature monitoring,and comprehensive diagnosis technology for operating status.Combined with temperature rise tests and case analysis,the operating status diagnosis technology for vacuum circuit breakers is studied.First of all,this paper uses ATP transient simulation software to analyze and study the transient characteristics of switching overvoltage in the process of three-phase synchronous breaking and three-phase different phase breaking of vacuum circuit breaker,and draws the conclusion that the mechanical characteristics of vacuum circuit breaker directly affect the external operating performance of circuit breaker.Then,dynamic time warping algorithm is introduced and based on the two characteristic curves,By using the obtained normalization path to diagnose the operating status of the mechanical characteristics of circuit breakers,the shortcomings of previous methods for diagnosing the mechanical characteristics of circuit breakers that did not fully utilize the original data are compensated.Subsequently,this article uses Maxwell finite element simulation software to establish a "magnetic field circuit" model that is consistent with the above model,and imports it into the Workbench collaborative simulation platform for electromagnetic temperature multiphysics field coupling analysis.Factors such as environmental temperature,load current,and contact pressure that significantly affect the contact temperature of circuit breakers are studied,and a contact temperature inversion calculation method using partial least squares regression algorithm is proposed,Solved the problem of direct monitoring of contact temperature in the arc extinguishing chamber of KYN series switchgear vacuum circuit breakers.Finally,drawing on the enterprise standard for circuit breaker status evaluation issued by State Grid Corporation of China in 2017,Q/GDW 10171-2016 "SF6 High Voltage Circuit Breaker Status Evaluation Guidelines",a comprehensive evaluation method based on combination weighting and weighted rank sum ratio(WRSR)was proposed by selecting four characteristic status indicators of vacuum circuit breakers and establishing a status evaluation system.This method is not only simple and reliable in principle,but also reliable in principle,Moreover,it can sort the status of multiple vacuum circuit breakers,which has better engineering applicability compared to traditional comprehensive diagnostic methods.