Research And Design Of Controllable Arc Grounding Device In 10kV Distribution Network

In the non-effective grounding operation mode of the neutral point of the distribution network,when a single-phase ground fault occurs,if it cannot be handled in time,it may induce a two-phase short-circuit ground fault,which affects the safe and stable operation of the distribution network,especially single-phase ground faults grounded in the form of arcs are harmful to the power system.The simulation test method is difficult to simulate the actual arc characteristics and cannot comprehensively test the reliability of single-phase ground fault line selection.Therefore,this thesis studies a device that directly manufactures single-phase arc grounding phenomenon and performs single-phase grounding fault line selection performance test on the feeder of 10kV distribution network operation,and designs a controllable arc grounding device for 10kV distribution network.The thesis uses STM32F407VET6 as the main control chip,and designs the main control circuit,arc ignition circuit and arc extinguishing circuit.Aiming at the problem of strong electromagnetic interference,optical fiber is used to transmit signal to control the operation of the arc ignition circuit and the arc extinguishing circuit respectively.The arc ignition circuit uses five sets of high-voltage generators to ignite the long gap arc,and the arc extinguishing circuit uses the magnetic blowing arc extinguishing technology to extinguish the long gap arc.Based on Keil uVision5 software,the voltage and current signal sampling program,frequency capture program,communication module program and human-computer interaction module program are designed,Tektronix MDO3024 oscilloscope measured the waveform of high voltage generator discharge,and verified the feasibility of the design of the high voltage discharge arc ignition circuit.Based on the test circuit of the magnetic blowing coil,the working characteristic waveform of the magnetic blowing coil is measured with an oscilloscope.The test waveform shows the correctness of the arc extinguishing circuit design.Using the single-phase ground fault simulation test platform of the 10kV true-type distribution network to simulate the occurrence of single-phase arc ground discharge.The waveforms of the single-phase arc ground voltage and current recorded by the recorder have verified the feasibility of the controllable arc grounding device.The experimental results show that the device is suitable for a non-effectively grounded 10kV distribution network at the neutral point.It can achieve precise control of the number of arc ground discharges and the discharge period.It can simulate long-gap single-phase arc grounding discharge phenomenon on the 10kV distribution network operated in the laboratory.The single-phase arc grounding phenomenon can occur repeatedly,which provides a basis for the reasonable line selection of single-phase ground faults.