To improve detection accuracy for a voltage phase by setting a voltage-detecting part thereby detecting a received voltage and setting a processing part thereby correcting a phase of the voltage.

One ends of power-receiving bus lines 41, 42, 43 of a spot network power-receiving facility are connected to bus lines 1, 2, 3 to which power is supplied and which are protected, controlled by power breakers 11, 12, 13 of an electric power company. The other ends are sequentially connected to primary switches 51, 52, 53, network transformers 61, 62, 63 and protector breakers 71, 72, 73. Terminal ends are connected to a network bus line 8. Detecting apparatus 91, 92, 93 detecting phases and a processing apparatus 10 processing detected phases and performing control, protection are connected to the power-receiving bus lines 41, 42, 43. At the processing apparatus 10, a correction process is carried out, that is, a correction value is added to the phases detected by the detecting apparatuses 91, 92, 93. Errors such as changes with time and individual differences of detecting apparatuses, etc., can be corrected, so that detection accuracy for voltage phases is improved and reliability of a power-receiving system is improved.