Research And Circuit Implementation Of Partial Discharge Signal Sampling Technology

With the rapid development of today’s society,electricity consumption continues to increase,resulting in an increase in power accidents.Among them,insulation failure accounts for the largest proportion,partial discharge is the main cause of equipment insulation failure,initial partial discharge will not cause insulation damage,but if it exists for a long time,it will completely destroy the insulation characteristics,breakdown equipment,affect the safe operation of equipment.As a traditional maintenance method,regular inspection takes a long time,which is not conducive to the stable operation of the power grid.Therefore,it is of great significance to study the online monitoring system to improve the maintenance efficiency.With the continuous development of semiconductor chips,partial discharge online monitoring circuit can also be continuously optimized,this paper takes a monolithic MCU as the core,designs a low-cost,high-efficiency,more complete partial discharge detection circuit,and puts forward solutions to related technical problems such as sampling speed,sampling accuracy,storage efficiency,transmission efficiency and so on in the partial discharge sampling process.The partial discharge signal is extracted by the three-phase power frequency high-pass filtering,and the partial discharge signal is obtained by synchronous acquisition and data comparison of the three ADCs.The rising edge counting time of the power frequency signal and the time of occurrence of effective partial discharge are recorded by a time recorder,and the phase relationship between partial discharge occurrence is determined by calculation;The analog unit circuit of the monolithic STM32H743 realizes the A/D acquisition of three signals and the comparison of analog signals to save analog circuits;Data computing,storage,and transmission are accomplished by using high-performance MCU.According to the proposed partial discharge sampling scheme,this paper designs the signal conditioning circuit,microprocessor circuit,interface circuit,embedded program and graphical display interface of the host computer.The hardware circuit functions and indicators of the module are tested in the laboratory,and the overall function of the system is tested by simulating the partial discharge signal.The experimental results show that the design circuit works normally,and can detect the three-phase partial discharge signal,with a time resolution of 0.5μs,a sampling accuracy of 12 bit,and a phase resolution of 0.01°,achieving the expected effect.