Electronic three-phase electricity meter

Abstract

Abstract 1. An electronic three-phase electricity meter, wherein a multiplier unit (MR, MS, MT) is provided for each phase, supplied at its input end with signals proportional to the current and voltage associated with the phase, and emits a power-proportional output signal (~Ur , ~Us , ~Ut ) that is added to the output signals of the other multiplier units to form a sum signal which is converted in a quantizer (Q) into a pulse train (I1) having a power-proportional frequency and then integrated with respect to time in a counting device (Z) for the energy to be detected, and the result displayed, characterised in that for one (R) of the three phases (R, S, T) an additional power detection device is provided, consisting at least of one multiplier unit (MR1, MP) and a test quantizer (Q1), which device supplies at its output end a pulse train (I2) having a power-proportional frequency, and that a comparator device (E) is provided for the two pulse trains (I1, I2) supplied by the quantizer (Q) and the power detection device, which comparison device triggers a signal change in a display unit (L) when the ratio of the frequencies of the two pulse trains (I1, I2) exceeds the limits of a specified tolerance band, these limits being selected such that the breakdown of an essential component leads to the exceeding of a limit, existing function elements (WIR, WUR, MR; WIR, WUR, TR, INR) of the three-phase electricity meter (DZ) also being used for the additional power detection device (Fig. 1, Fig. 2).

Inventors

• 👤 Günter Steinmüller
• 👤 Gunther Vieweg

Bibliographic Details