| 摘要 |
PROBLEM TO BE SOLVED: To enable a user at an ordinary home or a factory to immediately monitor the electric power using state by transmitting the detected instantaneous power consumption by radio, comparing the received power consumption with a target value, and displaying them. SOLUTION: A measuring circuit 11 of a measurement section 1 compares a power supply voltage Ve measured by connecting a power cord 6 to an electric outlet 7 fitted to a wire 4 and the output voltage Vi, corresponding to the instantaneous current Ii outputted from a current transformer 5 with a reference voltage Vs to detect a digitally converted voltage V and the current I for each phase. An arithmetic circuit 12 calculates the average value during 1 sec of the product of the voltage V and the current I, to obtain the average value in 1 min as an instantaneous electric power P (kW). It is integrated minute to calculate an electric power quantity ΣP(kWh), and an instantaneous electric power P and the electric power quantity ΣP are transmitted from a radio transmitting circuit. The radio receiving circuit of a display section receives them, an arithmetic circuit obtains the ratio between the electric power quantity ΣP and the target value, calculates the energy saving degree, and converts the electric power quantity ΣP into contract rate, and a display circuit displays them. |
