Inrush Current Parameters Associated with Back-to-Back Switching of Capacitors in a Bank

Abstract

Back-to-back switching of 50 kVAr capacitors, in a capacitor bank of 200 kVAr is investigated experimentally. The switching inrush currents in a three-phase, 200 kVAr, 415 V Automatic Power Factor Correction panel at power frequency are captured in the laboratory. The characterizing features of inrush current are reported and analyzed. The commercially available two makes of switches (contactors) are used to compare the inrush currents with and without their pre-insertion resistors (PIR). The inrush current scenario of the experimental setup is modeled in EMTDC/PSCAD to ascertain the results. The ratio Ipeak/IN for both the contactors without PIR exceeded the limit mentioned in IEC 60831-1 Ed 3.0 : 2014. 2017, Copyright Taylor & Francis Group, LLC.