Patent ID: 7768751

Claim:
A photovoltaic energy conversion system comprising: a photovoltaic array configured to generate a direct current (DC) power, where the photovoltaic array comprises a first rail and a second rail; an inverter configured to convert the DC power into alternating current (AC); and a ground fault detector and interrupter coupled to the first and the second rails of the photovoltaic array, the ground fault detector and interrupter configured to detect a diagnostic signal and ground fault conditions in the photovoltaic array, and to interrupt operation of the photovoltaic energy conversion system when either a ground fault condition is detected or when the diagnostic signal is not detected, the ground fault detector and interrupter including: a current transducer configured to receive the diagnostic signal and to couple to the first and second rails of the photovoltaic array so as to enable the current transducer to sense a differential current between the first and second rails, and wherein the current transducer is configured to both transduce the diagnostic signal on to a processing chain and transduce a fault-detection signal on to the processing chain, the fault detection signal being indicative of the differential current between the first and second rails of the photovoltaic array; and a controller configured to detect the diagnostic signal and the fault-detection signal.