US Patent 9525286 Shutdown system and method for photovoltaic system

A method and system is provided for achieving power shut down or disconnect at individual solar panel level for a DC solar power system. The system provides fail safe power disconnect for emergencies or electrical system maintenance. A high-frequency current source signal is transmitted over DC power lines to each junction box of a photovoltaic panel array. The high frequency signal is transmitted concurrently with the DC power, and is isolated from an inverter by an inductor. A communications receiver circuit controls the PV panel to short circuit the PV panel output terminals and disconnect the PV panel from the output terminals in response to the high-frequency signal.