Improving Static Energy Meter Robustness Against Conducted EMI with an Analog Low-Pass Filter

Static energy meters are used for billing purposes of the energy consumption. Those that utilize a Rogowski coil as their current transducer have shown the highest susceptibility to conducted electromagnetic interference resulting in misreadings. These disturbances occur due to pulsed currents with steep slopes with higher frequency content, drawn by nonlinear household appliances. This has resulted in over- and underestimations of the energy bill, and even in a perceived energy generation. This article describes improving the robustness against conducted electromagnetic interference by using the orthogonality of power flow principle, thus focusing only on the fundamental, in contrary to the energy metering trend of increasing the measurement bandwidth. A first-order low-pass filter is implemented between the current transducer and the amplifier to reduce interference without affecting the 50 Hz signal. The results show a reduction of errors from 1632% down to below 2.5%.