Parallel Impulse Current Shunt Performance of Multiple MOVs for 500 kV Series Compensation

Abstract

As an important component of the transmission line series compensation device, MOVs have the strong nonlinear characteristics to limit the overvoltage caused by line fault and protect the capacitor banks in 500kV lines. We studied the parallel impulse current shunt performance of multiple MOVs and the influence of the mixed-use of new MOVs with served MOVs for different numbers of MOVs on impulse shunt performance. We conducted 500 kV MOV parallel impulse shunt tests under three conditions of 9-served+2-new, 11-served and 9-served. We found that when MOVs with different V-I characteristics are connected in parallel, the impulse current action characteristics of a single MOV will not be affected. When the number of MOVs in parallel is changed from 11 to 9, the dispersion of impulse current does not change significantly. When two served MOVs are replaced with two new MOVs (with a 1% increase in DC U <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2mA</sub> ), the average dispersion of impulse current increases by 2.81%, and the average maximum deviation increases by 5.93%. If the margin is sufficient when MOVs in the whole group are damaged, they can be replaced with matched new MOVs.