Following initial studies showing that conducted electromagnetic interference (EMI) can lead to large error readings of static electricity meters, VSL performed a thorough verification study confirming that wideband currents produced by non-linear, fast-switching loads indeed can lead to significant error readings of static meters. Key parameters of the EMI causing the errors are a short rise time and large peak height of the current step. When dimming linear or non-linear loads such as heaters and energy-saving lamps, the (lack of) internal filter in the dimmer has a large influence on these key parameters.

Recent studies showed that static electricity meters can generate wrong metering results when exposed to conducted electromagnetic inference caused by electronic appliances, consisting of waveforms with very steep rising edges in combination with large peak amplitudes. To identify more waveforms that can cause errors, we captured a large series of waveforms of common household appliances, and after analyzing these waveforms we selected a number of waveforms for testing a static electricity meter.

Previous studies regarding static energy meter errors under non-sinusoidal load conditions have shown that these meters can produce erroneous readings. This paper describes an investigation done using loads consisting of a commercial lighting dimmer in combination with either a resistive heater or an array of various energy-saving lamps. Dimmer impedance and phase firing angle were gradually adjusted to change load conditions. Several meters showed dramatic variations in metering error under different load conditions. In the most extreme case, metering errors ranged from five times the energy consumed by the load to registering almost no energy. Though perhaps not typically found in households, the load combinations used in this study were able to highlight sensitivities of different static energy meters to changes in load conditions.

In this paper we present the design and implementation of a new flexible testbed for testing electricity meters with conducted EMI in the frequency range up to 150 kHz. This testbed is based on separate generation of voltage and current test signals with arbitrary waveforms. Different transconductance amplifiers were characterized for their suitability to generate the highly-distorted current waveforms required for advanced testing of electricity meters. The complete setup was validated by comparing test results on a meter showing error readings under conducted EMI with earlier test results obtained using a setup based on a power source in combination with real physical loads. The good validation results of the new testbed proof the setup is very suitable for advanced calibration or testing of static electricity meters under wideband conducted EMI. The setup and waveforms presented in this paper will be used as input for improved standardization of electricity meters type testing.

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