On-line Detection Research Of Vacuum Degree Of On-board Vacuum Circuit Breaker Of EMU

In recent years,because the continuous improvement and development of electrical power system,vacuum circuit breaker,as an important part of main circuit breaker,is more and more widely used in EMU trains.Relying on its special medium with high vacuum,vacuum circuit breaker has the advantages of compact structure,good arc extinguishing performance and long service life.The vacuum degree inside the arc extinguishing chamber directly determines whether the arc extinguishing is reliable and effective.The advantages and disadvantages of the vacuum directly affect the opening performance of the line.In order to ensure the normal operation of its safety,the detection of vacuum degree of vacuum extinguishing room is particularly important,and the timely acquisition of the operating state of vacuum extinguishing room has become a development element restricting the research in this area.This article briefly expounds the research backdrop and the development of vacuum circuit breakers,as well as the research priorities at home and abroad,and the question that understands vacuum test needs to be resolved.Compared with off-line detection,on-line vacuum detection has the advantages of good real-time performance,no need to change the structure of arc extinguishing chamber and long service cycle.It will become a major development trend of real-time vacuum detection in the future.The research methods of on-line detection mainly include shield potential method,partial discharge method,coupling capacitance method and so on.This time,based on the combination of shield potential method and coupling capacitance,the vacuum degree of vacuum interrupter is measured indirectly,and the potential value reflects the advantages and disadvantages of internal vacuum degree in time.This paper establishes the correspondence between the internal vacuum degree and relative permittivity based on the Ke-Mo equation and the ideal gas equation.,according to the finite element software simulation analysis of the interrupter chamber model,the simulation the si-mulation data between the shield potential and vacuum degree are obtained.The feasibility of the simulation result is verified by the subsequent experimental research of on-line detection.Focusing on the design of the hardware circuit and the writing and implementation of the softw-are program,the coupling capacitor probe is used to detect the voltage signal,the signal conditioning circuit is used for the output of the collected data,the microcontroller and the peripheral circuit are used for control,the LCD display module is used for real-time display,wh-ich is transmitted to the host computer for the final display via the RS-232 serial protocol.Afterward,an online testing experimetal platform is estblished for obtaining the potential data,including a vacuum calibration system,an online testing system and high-voltage regulation system.In accordance with the experimetal procedure,the coupling potential data is measured under different vacuum ranges from 1.0×10^-3Pa to 1Pa,Comparing with the simulation results can get a consistent change pattern,the finite element simulation analysis is confirmed by the online experiment system,which provides a research idea for the subsequent online detection of the vacuum inside the vacuum interrupter.