In this paper: a new strategy of anti-islanding photovoltaic (PV) power plant has been introduced. A new islanding detection strategy depending on power line signaling and control by inverter and numerical relays proposed in the literature. By generating, detecting and comparing between signals on the distribution feeders from the substation to the down-stream Distributed Generation (DG), the subtraction value of two signals at the DG site will be indicator for islanding. The scheme is a remote effective detection technique and more expensive than other techniques. The strategy depends on the embedded system containing the power line signaling and both PV inverters and Numerical(microprocessor based) relays. Inverter technology and control have been discussed.