Misreadings of Static Energy Meters due to Conducted EMI caused by Fast Changing Current

Abstract

Readings of static energy meters can be affected by conducted electromagnetic interference (EMI). Previous research reported many cases where lower and higher readings of static energy meters were observed. In this paper experiments with a water pump, controlled by speed regulators, resulted in huge errors in energy readings of static meters with respect to a reference meter. The speed regulators are intended to be used in conjunction with such water pumps. The tests were performed using a non-distorted mains power supply created by a four-quadrant amplifier with an internal impedance in accordance with the standards. The deviations observed are between −91% and +175% compared to the reference meter. The current waveforms attributed to these large deviations show large spikes with rise times of a few microseconds.