A novel controlled switching strategy of back-to-back capacitor banks considering the prestrike characteristics of vacuum circuit breakers

Abstract

Controlled switching of capacitor banks is an effective way to suppress the inrush current during capacitive-making operations. The objective of this paper is to determine the influence of the prestrike characteristics of four types of vacuum circuit breakers (VCBs) combined with two types of controlled switching strategies on the suppression effect of the inrush current. The four types of VCBs are cup-type axial magnetic field (AMF) single-break VCB, spiral-type transverse magnetic field (TMF) single-break VCB, cup-type AMF double-break VCB and spiral-type TMF double-break VCB. The prestrike characteristics of the four types of VCBs are investigated by synthetic tests. The two types of controlled switching strategies are the traditional controlled switching strategy (the closing command depends on the mechanical touch instant of the two contacts in VCBs) and the novel controlled switching strategy (the closing command depends on the 50% pre-arcing time ta50 of the VCBs). The results show that the spiral-type TMF double-break VCB combined with the novel controlled switching strategy is the best choice for applying back-to-back capacitor bank controlled switching.© 2017 Elsevier Inc. All rights reserved.