Abstract
Faults in the DC collector circuits of a photovoltaic plant are a cause for major concern due to the damage they may cause to equipment. Fault protection is required for ground faults, line-to-line faults and arc faults. Typically, the magnitude of short-circuit currents of PV modules are similar to that of load currents which makes fault detection and protection difficult to carry out on the DC system. The DC collectors of a PV plant consist of combiner boxes where PV arrays are connected and inverter DC buses where combiner boxes are connected. This paper investigates the fault contribution from the PV modules on the combiner boxes and inverter DC buses in relation to typical PV module data on an isolated section of the DC network of a plant using the ETAP simulation tool. A fault detection and protection scheme for the main faults in a DC PV system is proposed based on previous research, for complete protection of the DC collector circuits.