Ground Fault Location Method for DC Power Sources

Direct current (DC) power sources such as solar panels and batteries are becoming essential in the new electrical power systems. These types of DC power sources require of many cells to achieve an optimal operation voltage making difficult the fault diagnosis, especially ground faults, the most common type. In this paper, a new ground fault location method is proposed. The new method is based on the voltage measurement of a grounding resistor between three positions: the positive, the midpoint and the negative terminals of the protected DC power source. The method enables both the location of the fault and the resistance fault estimation. Additionally, for more complex topologies, the output current of each branch is used to identify the parallel branch where the ground fault is. The method has been validated by means of the simulation of a six-branch battery pack connected to an AC-DC inverter obtaining promising results.