GROUND FAULT MONITORING SYSTEM FOR AN ENERGY STORAGE SYSTEM

A ground fault monitoring system includes an isolation monitoring unit, a first main switch, a second main switch and a control unit. The isolation monitoring unit is arrangeable between an energy storage system and a ground element. The switches are arrangeable between the energy storage system and an external energy supply system. The isolation monitoring unit includes a first, second and third switchable resistor branches. The control unit is configured to close the switches during charging of the energy storage system for connecting the energy storage system to the external energy supply system and to disconnect the first switchable resistor branch from the energy storage system and connect the second switchable resistor branch and the third switchable resistor branch to the energy storage system for monitoring a current leakage to the ground element during charging of the energy storage system.