Study On Conduction Coupling Mechanism Of Relay Protection And Valve-controlled Equipment In Hvdc Converter Station

Converter station is a place where electromagnetic interference is very serious.With the increasing capacity of power grid and the application of intelligent devices,in order to realize the basic functions of measurement,transmission and control in power grid,a large number of intelligent devices have been installed in relay protection system,automatic devices and communication equipment.The number of disturbance sources and sensitive devices in converter station has increased tremendously,and the interference problem of secondary system has become increasingly prominent.In this paper,the problem of different types of conductive electromagnetic disturbance caused by two different disturbance sources in converter station is preliminarily studied from two aspects.According to the different sources,the conductive electromagnetic disturbance caused by ground potential rise in traditional converter station and the conductive electromagnetic disturbance caused by transient voltage and current in the primary circuit in the switching process of converter valve in flexible DC converter station are respectively studied.This paper mainly analyses its coupling mode and transmission process and calculates its disturbance level.It emphatically analyses the waveform characteristics and maincomponents of conducted electromagnetic disturbance signal,and preliminarily calculates and summarizes the frequency composition of disturbance.Finally,the influence to the secondary cable of conducted electromagnetic disturbance is introduced.In this paper,a simulation experiment is arranged according to the actual conditions,and some simulationresults are compared with the experimental data,and the relevant phenomena and calculation results are analyzed.