a fuel cell system or hvdc power source includes a fuel cell or dc power source having a high voltage direct current bus including y - capacitors , which connect the hvdc bus terminals to chassis or safety ground , and a fault current discharge compensation circuit interconnected with the hvdc bus . a monitoring circuit monitors a fault discharge current of the y - cap circuit and generates a fault signal when the fault current occurs based on a rate of change of a voltage of the y - cap circuit . a switching circuit redirects the majority of the fault discharge current .