Electronic Transformer In 110kV Intelligent Substation On The Characteristics Of Electromagnetic Interference And Suppression Methods

With the wide application of smart substations,as the device electronic transformers often used in it,it is often in a complex electromagnetic environment when signal data is collected,and the failure of electronic transformers has become more common.Therefore,it is worth studying the electronic interference received by the electronic transformer,and can find a suppression method to prevent such accidents from happening again.The VFTO generated by the GIS isolation switch will cause greater electromagnetic interference to the electronic transformer through different coupling methods.This article focuses on the effects of VFTO on the conducted and radiated interference produced by the transformer and the corresponding suppression methods.The main work is as follows:(1)Theoretical analysis of the research on the electromagnetic interference characteristics of electronic transformers,including the characteristics of electromagnetic disturbance sources and VFTO electromagnetic disturbance sources common in substations,the coupling method of electromagnetic interference with extremely fast transient overvoltage,and the structure of electronic transformers And working principle.(2)Based on the research on the electromagnetic interference characteristics of electronic transformers,the effects of VFTO on the conducted and radiated interference produced by the transformers are studied and simulated.The frequency characteristics of the voltage divider ratio of the capacitive voltage divider in the electronic voltage transformer are studied.According to the GIS and electronic transformer structure of Yongchuan 110 k V Nanjiao Intelligent Substation,the simulation model is built using the software ATP-EMTP to open and close the operating disconnector The VFTO signal at the time simulates and analyzes the conduction generated by the electronic voltage transformer to verify the results of theoretical research.In addition,the VFTO radiated electromagnetic field penetrates the non-metallic terminal block to analyze and calculate the transient electric field and magnetic field of VFTO in GIS.(3)Based on the theoretical analysis of the anti-interference method of the electronic circuit of the electronic transformer,a multi-layer coaxial capacitor with a parallel structure is proposed to suppress the VFTO conducted interference output from the capacitive voltage divider,and a four-layer multilayer coaxial capacitor with a parallel structure is designed.Aiming at the VFTO radiation interference of the terminal block leakage,a method of increasing the length of the connecting cylinder of the collection box and reducing the diameter of the terminal block is proposed to reduce the intensity of the VFTO radiation electric field and the radiation magnetic field in the collection box.In order to test the effectiveness of the proposed method,a simulation example of the simulation model was built and the simulation experiment was performed.