Capacitor Switching Inrush

Peak inrush current and frequency when energizing a shunt capacitor bank, with series-reactor limiting and reclose interval.

Inputs

Capacitor bank rating Mvar

Upstream short-circuit power S_sc MVA

System voltage (line-line) V

System frequency Hz

Series reactor (% of X_c) %

Results

Note — Inrush is an L-C transient between the source and the bank; frequency is high (hundreds of Hz) and peaks can be tens of times the rated capacitor current. A series reactor (typically 5–7 % of X_c) limits both inrush and harmonic resonance. The reclose interval is a screening minimum (half the inrush period); follow the bank and switchgear maker's data. Verify with the network study.