| With the rapid development of China’s economy,the scale of the power grid is expanding,and people’s requirements for power supply reliability and power quality are constantly increasing,resulting in more and more freque nt regulation of system voltage and reactive power,and the availability of capacitive reactive power compensation equipment has become a Important production technical indicators.As the most widely used reactive power compensation device in power grids,power capacitors have the highest failure rate among all transformers and power distribution equipment.Their operating status and detection technology have received much attention in the industry.The conventional power capacitor state detection method is usually a power failure test,which not only can not find its operation failure at any time,but also reduces the utilization rate of the compensation device while increasing the operation and maintenance workload,weakening the control ability of the sys tem voltage and reactive power compensation.Since the device is in the non-operating state when the power voltage and load test,not a true reflection of insulation failure status and trends of the actual running state capacitors,has great limitations.Therefore,it is urgent to carry out further research on power capacitor online monitoring technology to accurately grasp the real-time operating status of power capacitors,and to provide alarm and fault diagnosis when necessary,so as to avoid accidents caused by faults or even further expansion,and prevent unnecessary asset losses.And effectively guide the implementation of the best maintenance strategy for power capacitors,its engineering application value is significant and far-reaching.In this paper,a complete set of on-line monitoring technical schemes that are convenient for field implementation is proposed based on the research on the mechanism of power capacitor faults in operation,and a power capacitor fault early warning and status monitoring device is researched and designed.The first is to analyze the common faults and causes of power capacitors in the power system,study the mechanism of their faults,and determine the state quantities that need to be monitored for operating state recognition.Secondly,the conventional monitoring apparatus are subject to compensate for the field,there is a choice of resistance as the discharge power or discharge of the capacitor element without secondary discharge coil voltage signal output,the first state capacitor is proposed based on the power bus voltage monitoring program signal,i.e.,by Collect the secondary voltage signal of the bus-side voltage transformer and the secondary current signal of the loop current transformer of the complete set of po wer capacitors,and realize the online monitoring and analysis of the power capacitor and the series reactor by constructing a state monitoring equivalent circuit.The secondary output of the coil can also realize the online monitoring of the discharge coil.Then,research and propose an adaptive network-based fuzzy inference system(Adaptive Network-based Fuzzy Inference System,ANFIS)power capacitor insulation state diagnosis method,and divide the degree of deterioration of insulation defects,effective ly prevent the power capacitor from moisture and Defects caused by aging insulation cause its operation failure.In this study,a set of power capacitor fault early warning and status monitoring devices were developed and connected to the grid for operatio n.Through the design of the online monitoring device for power capacitors,the DSP chip model TMS320F28335 produced by TI was selected,and the analog acquisition circuit,logic control circuit,memory circuit,communication circuit and human-machine interface were optimized to make the online monitoring device reliable.,Meets the design requirements,and provides strong technical support for power capacitor fault warning and condition monitoring. |
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