Electric power measuring instrument and method for judging wiring state of AC circuit and electric power measuring instrument

Abstract

To obtain an electric power measurement apparatus with which it is possible to quickly determine the state of wire connections. Provided is an electric power measurement apparatus (100), connected to an AC circuit of three-phase three-wire type, for measuring the electric power of the AC circuit, said apparatus comprising: a voltage detection unit (11) for detecting a voltage signal (transformer output X200); a current detection unit (12) for detecting a current signal (converter output X300); a measurement value arithmetic unit (13) for calculating the measurement value of electric power from the voltage signal and current signal; and a wire connection state determination unit (15) for determining the state of wire connections of the voltage detection unit (11) and current detection unit (12) to the AC circuit depending on whether an inputted power factor condition and a combination of the phase angle [phi]V of voltage, the phase angle [phi]I of current, and the phase angle [phi]P of electric power calculated using the voltage signal and current signal conform to a criterion.

Description

technical field [0001] In particular, the present invention relates to a method for judging the connection state in a power measuring instrument that measures voltage and current of a 3-wire AC circuit, and evaluates voltage, current, power, reactive power, power factor, and frequency. ・Measurement, measurement and display of electric power etc. Background technique [0002] In order to calculate the measured value and measured value in the AC circuit correctly, the input from the current transformer and transformer installed in the circuit is usually introduced into the measuring device, but if the wiring is not appropriate and the so-called miswiring occurs, the correct value cannot be obtained. display. [0003] Therefore, a three-phase, three-wire type electric power and electric power measuring meter has been proposed, that is, based on the phase angle between the phases of the current and the phase angle between the voltage and the current, the specific voltage corresp...

AI Technical Summary

Problems solved by technology

[0005] However, although the above-mentioned electric power and electric power meter can judge when there is miswiring in the converter circuit, for example, when the transformer is wrongly wired, it may be wrongly judged that the miswiring has occurred in the converter. , making it impossible to reliably determine miswiring

That is, in the method disclosed in Patent Document 1, it is virtually impossible to accurately determine a wrong connection, and it is impossible to quickly correct it when a wrong connection occurs.

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