A primer on capacitor bank protection

Capacitor banks are applied in power systems to provide reactive power. The reactive power results in lower current in lines upstream of the bank improving system voltage and power factor and reducing line losses. Capacitor banks can be configured as filters for harmonic reduction. The protection systems for capacitor banks include fuses, surge arresters, and protective relays. This paper focuses on protective relaying philosophies of grounded and ungrounded Y connected shunt capacitor banks, which are commonly applied on industrial and utility power systems