The Capacitor Protection Relay (KSR) is used for supervision of 3-phase capacitor stages in reactive power compensation systems. It is able to recognize different conditions both external and internal to the capacitor bank, which could be hazardous for the capacitors. The KSR measurement system acquires inputs of currents and voltage channels which are connected to the capacitor bank to monitor overload, unbalance, under and over voltage and more, to provide a comprehensive protection monitoring of the HT capacitor banks.