Patent ID: 9170284
Filing Date: 2015-10-27
Classification: G01R

Abstract:
1. An A.C. power measuring apparatus comprising: a voltage detecting unit configured to detect voltage waveforms of each of phases of a set of three insulated cables for supplying a three-phase A.C. power to a load, by performing a contactless measurement by electrostatic capacitance coupling, without making contact with the insulated cable; a current detecting unit configured to detect current waveforms of the set of three insulated cables, by performing a contactless measurement by electromagnetic induction coupling, without making contact with the insulated cable; and a processing unit configured to compute a power to be supplied to the load, based on line-to-line voltage waveforms, the current waveforms, and prescribed voltage values, by normalizing the voltage waveforms of each of the phases so that an amplitude ratio of the voltage waveforms becomes in accordance with a grounding type of the three-phase A.C. power, and obtaining the line-to-line voltages of the set of three insulated cables based on the normalized voltage waveforms of each of the phases.