A static, electric apparatus for measuring power and energy drawn from a power supply network

TLDR: In this paper, a static electricity meter has for each phase a signal conditioning circuit (10, 11 and 12) which detects the voltage and current and applies voltage pulses representing these quantities to a multiplexer (13), from which they are transferred sequentially through a multiplier (14) to a V/F converter (15), whose output signal is a pulse train having a frequency which is an expression of the power consumption on the phase detected at any time.

Abstract: A static electricity meter has for each phase a signal conditioning circuit (10, 11 and 12) which detects the voltage and current and applies voltage pulses representing these quantities to a multiplexer (13), from which they are transferred sequentially through a multiplier (14) to a V/F converter (15), whose output signal is a pulse train having a frequency which is an expression of the power consumption on the phase detected at any time. This pulse train is fed to a microprocessor (16) which counts the pulses and calculates the energy consumption on the basis of an incorporated time factor and transfers it to a random access store (18). The microprocessor also controls the signal transfer to the multiplexer so that the detection of the phases takes place in a arbitrarily varying order and with a frequency independent of the network frequence. This prevents a consumer from avoiding registration of consumption by synchronized connection of the load to the network with the metering system. To prevent inaccurate measurements because of ageing and temperature drift of the component of the electricity meter, the meter is designed to automatically perform self-calibration/adjustment on the basis of an accurate reference voltage source having long-term stability and very low temperature drift.