Analysis and mitigation on switching transients of medium-voltage low-harmonic filter banks

Abstract

This paper presents the switching transients of medium-voltage low-harmonic filter banks, which have alower back-to-back inrush current and higher transient recovery voltage (TRV) compared withcapacitor banks. The switching transients of the filter banks aredescribed by the analytical approach and field measurementsfor 150 MVA back-to-back filter banksare provided to support the switching phenomena described in this paper.As a mitigation measure of the high transient recovery voltage, a double-breaker type switchgearisanalyzed in terms of the operating sequence and the time of the upper and lower breakers. From the analyses, an operation scheme forthe double-breaker switchgear is proposed toavoid insulation failure of the breaker during the interruption by mitigating the transient recovery voltage across each breaker.