| In recent years,UHVDC technology got rapid development in our country,several project put into operation or under construction.Secondary intelligent components in converter station widely involved in protection,communication,control,measurement and monitoring,vulnerable to lightning damage.The transient electromagnetic interfere nce caused by lightning is a potential threat to the secondary system due to its characterist ics of high amplitude and wide frequency band.This paper mainly studies on coupling mechanism of electromagnetic interference caused by lightning transient ground potential rise on intelligent component.In this paper,three generation mechanism of transient ground potential rise in substations is analyzed,which is based on the lightning ground potential rise,the fault ground potential rise and the switching operation ground potential rise.The equivale nt circuit of the intelligent component is established by the ground potential rise.The ground potential rise is simulated according to an actual event of lightning ±800kV UHVDC converter station and single point current and dispersed current of ground potential rise is compared.Based on the principle of DC field divider in converter station,the transfer function of the voltage divider is derived,and the transient response characteristics of the DC voltage divider under three conditions are analyzed.The calculation model for ground potential rise caused by switching operations coupling to the circuit of “divider-secondary cable-intelligent component” is established through Ansys Maxwell finite element software.And the influence of shield grounding mode on the electromagnetic disturbance of the ports of divider and IEDs is simulation studied.Finally,a simulation experiment platform is built in the laboratory.Interference characteristics of lightning ground potential rise to intelligent components is studied by means of simulation test. |
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