AN ELECTRIC POWER SYSTEM

An electric power system comprises a direct voltage rail (101), battery elements (102-104) connected with supply-converters (105-107) to the direct voltage rail, and load-converters (111-113) for converting direct voltage of the direct voltage rail into voltages suitable for loads of the electric power system, where the supply-converters and the load-converters are connected with over-current protectors (108-110, 114-116) to the direct voltage rail. The electric power system further comprises a capacitor system (117) connected to the direct voltage rail and capable of supplying fault current for switching an over-current protector into a non-conductive state in response to a fault causing a voltage drop at an electrical node connected to the direct voltage rail via the over-current protector. The capacitor system may comprise one or more high-capacitance electric double layer capacitors. The fault current available from the capacitor system enables a selective protection.