Arc Fault Detection Schemes for an Automotive 42 V Wire Harness

Introduction of higher DC system voltage distribution networks greater than 24V in future passenger vehicles appears to be an unavoidable consequence of meeting the increasing future electrical power demand. Higher voltage electrical distribution networks in vehicles force considerable component and system changes regarding electrical safety and reliability. In the event of an arc fault, e.g. when a wire is pinched or cut, or disengaged terminals under load etc., the resulting current may be significantly lower than the trip current of the protection devices such as fuses and circuit breakers. In these cases either the fault is cleared late (depending on the time/current characteristics of the fuse) or, in some cases fault may not clear, causing considerable damage and safety hazards. Two cost effective arc fault detection schemes were developed, built and tested with different loads including motor loads to clear both parallel and series arc faults in a 42 V DC network. This paper presents the details of the developed arc fault detection schemes and test results under several fault conditions.