Conducted interference on smart meters

The increasing conducted interference caused by modern electronic equipment is causing more problems for electronic, or static, energy meters. These meters are called smart meters when equipped with a communication link, and are replacing the conventional electromechanical meters. It is known that conducted electromagnetic interference, for instance due to active infeed converters as used in photo-voltaic systems, can cause a lower static energy meter reading. In a controlled environment it was found that three-phase meters showed, for the first time, higher energy readings. These experiments were performed using an ideal sinusoidal voltage from a four-quadrant power amplifier. Increased energy reading of +276 %, but also decreased energy meter reading of -46%, was observed. The Rogowski coil current sensor gives the positive and the Hall effect-based current sensor results in a negative deviation. Measurements were repeated, with more meters, and supplied from standard, low internal impedance, mains supply in the laboratory. Now positive reading up to +582% negative reading down with -32% were registered.