DISTRIBUTED POWER SUPPLY SYSTEM AND EFFECTIVE ELECTRIC POWER ESTIMATION METHOD

To estimate an effective electric power at a low cost and with a simple structure, and prevent an inverse load flow.SOLUTION: A distributed power supply system (1) communicated with a commercial power system (2) to operate a dispersion type power source (20), comprises: a converter (4) converting any one phase power of three-phase powers received from the commercial power system (2) into a single phase power supplied to loads (5 and 6); basic voltage measurement parts (16A and 16B) measuring a basic voltage (Vuw) as a voltage between electric wires supplying a power from one phase power and the dispersion type power source (12) to the loads (5 and 6); basic current measurement parts (7 and 8) measuring basic currents (Ir and It) as a current flowing two power wires supplying the one phase power from the three-phase powers in a power reception point (Rp); an effective electric power estimation part (12) estimating an effective electric power in the power reception point (Rp) on the basis of the basic voltage and the basic current; and a control part (12) performing an operation control for preventing an inverse load flow on the basis of the effective electric power.SELECTED DRAWING: Figure 1 【課題】低コストかつ簡易な構成で有効電力を推定し、逆潮流を防止する。【解決手段】商用電力系統（２）に連系して、分散型電源（２０）を運転する分散型電源システム（１）であって、商用電力系統（２）から受電した三相電力のうちいずれか一相の電力を、負荷（５，６）に供給される単相の電力に変換する変圧器（４）と、負荷（５，６）に一相の電力及び分散型電源（１２）からの電力を供給する電力線間の電圧である基礎電圧（Ｖｕｗ）を測定する基礎電圧測定部（１６Ａ，１６Ｂ）と、受電点（Ｒｐ）における、三相電力うちの一相の電力を供給する二つの電力線を流れる電流である基礎電流（Ｉｒ，Ｉｔ）を測定する基礎電流測定部（７，８）と、基礎電圧と基礎電流に基づいて、受電点（Ｒｐ）における有効電力を推定する有効電力推定部（１２）と、有効電力に基づいて、逆潮流を防止する運転制御を行なう制御部（１２）と、を備える。【選択図】図１