System and method of sensing and isolating a ground fault in a dc-to-ac power conversion system

A method of isolating a ground fault within a DC-to-AC power conversion system that includes a plurality of DC power source assemblies coupled to a power inverter through a combiner, the method comprising:

• sampling current on a plurality of conductors of the combiner and a ground conductor coupled to the plurality of DC power source assemblies;
• identifying a potential ground fault within the DC-to-AC power conversion system from the sampled current;
• identifying a faulty DC power source assembly from the sampled current corresponding to at least one of a positive conductor and a negative conductor of the combiner;
• and
• electronically activating a pair of DC breakers to disconnect the faulty DC power source assembly from the power inverter.

A photovoltaic (PV) power system comprising:

• a plurality of PV arrays each configured to generate a direct current (DC) output from received solar irradiation;
• a power inverter electronically coupled to the plurality of PV arrays to receive the DC output therefrom and invert the DC output to an AC output;
• a combiner coupling the DC output from the plurality of PV arrays to an input of the power inverter, the combiner comprising a plurality of positive conductors and a plurality of negative conductors, each having a DC breaker provided thereon;
• a ground conductor coupled to the plurality of PV arrays and having a current sensor provided thereon;
• and
• a controller in operable connection with the DC breakers, the controller programmed to:
• locate a ground fault corresponding to one of the plurality of PV arrays from sampled current data received from current sensors provided on a plurality of conductors within the PV power system;
• and
• decouple the PV array having the ground fault from the power inverter by electronically activating a pair of DC breakers corresponding to the PV array having the ground fault.