Abstract: Provided are an apparatus and method for accurately measuring electric power when a consumer receives electric power from an electric utility and supplies surplus electric power to the electric utility in power transmission/reception facilities connected in a Y-delta configuration. The apparatus includes a first power meter measuring an amount of electric power at a Y connection side, a second power meter measuring an amount of electric power caused by neutral circulating current at the Y connection side, and an operational unit subtracting a measured value of the second power meter from a measured value of the first power meter, and deciding an amount of actually consumed electric power. The second power meter includes at least one current transformer (CT) and a plurality of potential transformers (PTs). The at least one current transformer detects neutral circulating current (In) of a neutral ground conductor at the Y connection side.