Design And Application Research Of Partial Discharge On Train Cable Terminal Detection Sensor Based On Ultra High Frequency Method

The rapid popularization of high-speed trains has higher and higher requirements for power equipment.As train-mounted high-voltage cables are completely exposed to the air during operation,how to detect the partial discharge condition of train-mounted cable terminal and how to diagnose the discharge type of train-mounted cable terminal is a very important problem.In general,the cable body rarely local discharge,partial discharge in the cable terminal and cable intermediate joint.When partial discharge occurs in the middle connector of the cable or in the terminal,the ultra-high frequency(uhf)electromagnetic wave signal will be generated.The uhf signal can be received by the antenna sensor receiving the signal of this frequency band,so as to realize the detection of partial discharge.The signal range detected by the high-frequency method is generally 300MHz～3GHz,while the field interference is usually below 400 MHz.Therefore,the ultra-high frequency method can realize wide-band detection and has strong anti-interference ability.In this paper,the ultra-high frequency method is used to detect the partial discharge of on-board cable terminal.When partial discharge occurs in the middle connector of the cable or in the terminal,the ultra-high frequency(UHF)electromagnetic wave signal will be generated.The uhf signal can be received by the antenna sensor receiving the signal of this frequency band,so as to realize the detection of partial discharge.The uhf signal decays quickly in the cable body,so it is more suitable for detecting the cable intermediate joint and cable terminal.The signal range detected by uhf method is generally 300MHz～3GHz,while the field interference is usually below400 MHz.Therefore,uhf method can realize wide-band detection and has strong antiinterference ability.In this paper,the ultra-high frequency method is used to detect partial discharge in train cable terminal.First in this paper,we study the application of uhf frequency band antenna design and uhf partial discharge domain related literature,the first antenna is studied,some important performance parameters are widely used in the communication of UWB antenna,study sums up a series of monopole patch antenna design calculations required model,proposed for uhf detection of monopole patch antenna performance requirements related parameters.Then,this paper uses Ansoft HFSS simulation software to calculate the prototype parameters of the monopole patch antenna on the basis of the above,and carries out the simulation of the prototype antenna.After studying the antenna is widely used in the design of uwb technology,chose the meander technology as a way to optimize the monopole patch antenna,repeatedly used meander technology,optimize the prototype monopole patch antenna,will add trapezium structure and square slot antenna,optimized the ultra-wideband antenna,the optimized design of the antenna in the simulation software work relatively band has gone beyond 100%.Finally,this paper uses FR-4 substrate to make real antenna,and uses Keysight network analyzer to actually test the antenna performance.The actual measurement shows that the actual bandwidth of the antenna is better than that of the simulation design,and the change trend of the return loss of the real antenna is consistent with the simulation design.Then this paper designed three kinds of vehicle-mounted cable terminal defect models,and built the local discharge detection high-voltage experimental platform,the use of real antenna detection,and the analysis of the experimental results,the experimental results show that the antenna can effectively detect the local emission signal,and different local emission model has different signal distribution characteristics.Taking monopole patch antenna,meandering technology design was used to desing a PD detection uhf ultra-wideband antenna,the antenna in-kind proofing production and testing,to determine the antenna bandwidth,practical work produced three car cable terminal defect model and discharge test experiment,has carried on the related has proved that the designed antenna testing discharge capacity,the designed antenna has a certain practical application prospect.