Research And Design Of Comprehensive Protection System Of Mine-used Low-voltage Feeder Switch

The feeder switch is a power distribution switch underground in coal mines.Its main function is to accurately identify various electrical faults of underground power lines and quickly and accurately disconnect the faulty branch circuits,thereby ensuring the safety of underground power lines.With the continuous development of underground automatic coal mining technology,the scale of mines is also expanding.In the past,the disadvantages of slow action and poor reliability of traditional feeder switches have become increasingly apparent in the actual production process.Therefore,the performance of traditional feeder switches is comparable to the accuracy is difficult to meet the requirements of safe power supply for modern mine low-voltage power grids.Therefore,based on the characteristics of the downhole environment,it is necessary to conduct a more io-depth study on the protection techaology of the feeder switch.In order to further improve the overall performance of the feeder switch,this article has done the following research on the fault detection method,software and hardware design of the feeder switch:First,the current research status and development trend of feeder switches are elaborated and analyzed,and the current deficiencies in the protection of low-voltage power grids in coal mines are pointed out;For the power supply system where the neutral point of the underground is not grounded,systematically analyze the causes and changes of the underground leakage fault and overcurrent fault,and simulate the underground leakage fault and overcurrent fault,and analyze their respective fault characteristics.Secondly,the hardware circuit and software programming of the feed protection system are designed.The hardware circuit uses STM32F103ZET6 as the control core,and the corresponding signal processing circuit,phase sensitive protection circuit,negative sequence protection circuit,linear optocoupler isolation circuit and power metering circuit are designed;The software program design adopts a modular design method,and design the initialization program,leakage protection program,current detection program,voltage detection program,LCD liquid crystal driver program and other functional module subprograms.Finally,an experimental platform was built to verify the sampling error,leakage,overcurrent,and power measurement of the protection system,and the experimental waveforms and experimental data were obtained,which further verified the feasibility and correctness of the design.