Discussed are a power converting apparatus, a photovoltaic module, and a photovoltaic system including the photovoltaic module and the power converting apparatus. The power converting apparatus is capable of converting direct current (DC) power from the solar cell module into alternating current (AC) power, outputting the AC power to a grid, and detecting a signal indicative of abnormality in grid power caused by power cut or the like, thereby preventing an islanding operation.