Study On The Influence Of Overvoltage Of Intelligent Substation On Electronic Transformer And Its Suppression Strategy

Along with the rapid development of the global energy Internet,intelligent substation,as a key support for building a “strong smart grid”,based on advanced information technology and automation technology,realizes the automation and intelligent operation of the substation in the energy transformation and transmission process.In the rapid development of intelligent substation construction in China,the new type of electronic transformers aims to improve the informationization and intelligence of substations,and constantly seeks breakthroughs and upgrades in product digitization and integration,and has gradually applied to power systems in recent years.However,in the practical application of intelligent substation,electronic transformers frequently have faults such as combined unit alarm,sensor failure,and relay protection blocking,which are low in reliability and seriously hinder the electronic transformer in the intelligent power system.Further promotion and use,it is necessary to conduct research on electronic transformers in smart substations.In view of the fault of the electronic voltage transformer collector in the 500 k V Shennan substation power transmission,the fault of the electronic voltage transformer collector caused the alarm and the lockout.This paper first summarizes the research results of the electronic transformer and transient overvoltage at home and abroad.The research direction of the fault of electronic voltage transformer in Jincheng Substation is clarified.Then,the principle of three kinds of electronic voltage transformers is analyzed in detail.At the same time,based on the fault cases of Jincheng substation,the generation mechanism of transient overvoltage during the operation of circuit breakers and disconnectors is analyzed,and its harm and characteristics.Based on the field equipment conditions of Jincheng Substation,a reasonable test plan is designed to analyze the influence of the operation of circuit breakers and disconnectors at different positions on the secondary circuit of the voltage transformer.According to the experimental data analysis,the influence of the opening and closing operation of the isolating switch on the voltage transformer is greater than that of the circuit breaker;the closer the electrical distance of the voltage transformer is,the more serious the influence of the operating overvoltage of the isolating switch.Finally,by analyzing the characteristics of the transient over-voltage generated during the operation of the GIS device,a surge protector and a T-filter are added to the secondary circuit of the voltage transformer to suppress the influence of the over-voltage of the isolation switch.According to the fieldconditions of Shennan Substation,after the implementation of the operating overvoltage suppression strategy,the transient overvoltage of the secondary circuit of the voltage transformer during the operation of the isolating switch is tested again.The comparison analysis results show that the suppression strategy can effectively suppress the isolation switch operation.The influence of overvoltage on the electronic transformers verifies the feasibility and effectiveness of the proposed suppression strategy.