Electronic multiphase electricity meter - has regulated common supply for all individual phase measurement sections using separate secondaries

摘要

An electronic multiphase electricity meter with a number of electronic single phase measurement sections corresp. to the number of phases has a voltage measurement series resistor and a current measurement shunt in each section. It has a more economical current supply then similar circuits. A common power supply section (16) is provided for all three single phase sections (1, 2, 3) of a triple-phase meter. The amplitude in the power supply section is regulated so accurately that the voltages obtained from the secondary windings (18c, 18d, 18f) can be used directly to supply each section after rectification. For mutually isolated current and voltage circuits each measurement section has a secondary winding for each circuit. The pulse width modulator switching signal for a pulse width modulation type meter is fed to the amplitude modulator via an optoelectronic coupler or pulse transformer.