The paper focuses on an accurate predetermination of the peak inrush current that occurs at switching the multiple step capacitor banks in automatic low voltage power factor correction systems (LV-PFC). The analytical and numerical approach rely on the exact solutions of the time second order differential equations which model the entire dynamic process. The study is also valid in low level harmonic polluted environments and for both mechanic and static commutation. Some power quality aspects are also treated along with the estimation of electric stress exerted on electrical equipment. A case study allows the comparison of the obtained results with those reported in previous works and International Electrotechnical Commission (IEC) standards.

Keywords: Inrush current, Overvoltage, Switching phenomenon, Low voltage power factor correction (LV-PFC).