Research On Condition Monitoring Technology Of Shunt Capacitor Based On Wireless Sensor Network

The distribution network mainly relies on the reactive power of the high-voltage power capacitor switching and regulating system to achieve the purpose of improving power factor,reducing losses and improving power quality.Due to the complicated internal structure of the capacitor and frequent switching and switching,failures occur from time to time.Power capacitor damage is closely related to its own production and installation quality and operating site environmental conditions.How to ensure the reliability of capacitor operation has always been a technical problem faced by on-site operation and maintenance.It is of great significance to study on-site power capacitor operation status monitoring and fault diagnosis systems.By analyzing the signal performance characteristics of power capacitor operation failure,an online monitoring program of power capacitor based on wireless sensor network is proposed.Through the research and development of compact intelligent sensors,the operating parameters of the capacitors are fully monitored,and the voltage,current and temperature signal characteristics are extracted after the data is uploaded,which can comprehensively determine the operating status of the high-voltage parallel capacitors.First,design a miniaturized,high-precision capacitor unit monitoring current and temperature composite sensor for field needs,and design a wide-range discharge voltage and busbar current sensor for the on-site switching process to solve high-voltage energy acquisition,data transmission,high-voltage insulation and electromagnetic interference protection And other key technical problems;secondly,the sensors are networked through the ZigBee wireless network,and the convergence device is used to receive the measured current,voltage and other data,and the data is remotely transmitted to the background computer through the Ethernet;finally,the capacitor operating data is fully analyzed in the background system,Calculate and analyze parameters such as temperature,current limit violation,over-voltage and harmonics,and realize the identification and early warning of abnormal capacitor status and defects.This paper has deeply studied the key technologies of high-voltage energy extraction,miniaturization,high-precision and wide-range design of the capacitance unit monitoring sensor.The energy extraction and measurement of CT structural parameters have been determined through the analysis of magnetic core materials,magnetic field distribution and coil turns,and each design has been designed.The module circuit and program of the sensor;the short-distance,low-complexity ZigBee ad hoc network is realized by modbus communication protocol and rotation training method.The actual laboratory test verifies that the sensor has high measurement accuracy and reliable wireless network data transmission;the background system temperature,The functions such as current limit judgment and harmonic FFT calculation,and the power capacitor operation status monitoring system have laid the foundation for the improvement of the on-site operation and maintenance level.