Mass-market electrical products emit interference into the grid conductors, which has been shown to cause malfunctions of other connected products, power line communications equipment and grid infrastructure. At frequencies below 2 kHz, this conducted harmonic interference has been regulated for some years by normative standards and associated compliance testing as part of the EMC directive. However, advances in electronics, and the growth of electric vehicle chargers and renewable energy, have led to increasing amount of interference at higher frequencies in the so called “supraharmonic” range of 2-150 kHz. This interference is not regulated, and its growth is now causing serious concern to utilities and product manufacturers. In 2017, this led to action from the standards community with the establishment of a working group (WG) of the Power Quality (PQ) community (IEC SC77A) and the radio interference community (CISPR), to determine the gaps in the normative and regulatory requirements of the supraharmonic band.

One such gap is the lack of a rigorous, repeatable and acceptable measurement method, which is essential to establish a regulatory system for the supraharmonic range. To address this gap, IEC SC77A has convened an expert task force under WG9, to establish and publish a new normative method for the main PQ measurement standard IEC 61000-4-30. This WG9 has expressed their urgent need to develop a new metrological sound measurement method.

In order to develop emissions limits, compatibility levels must reflect the prevailing amount of interference that mass-market goods and grid equipment should operate without malfunction. Compatibility levels are presently defined taking only the laboratory testing environment into account. How well this assumption compares to real grid conditions and resulting behaviour of appliances must be confirmed. This requires measurements of real products using an artificial mains network (AMN) which will then be compared with measured emissions when the same products are connected in different electricity LV networks.

Emission testing of mass-market goods to ensure compliance against the limits will need to be done in the laboratory rather than the grid. This requires a realistic simulation of the grid which is achieved using an AMN. The AMN impedance characteristics are critical to ensure representative emission results. New grid impedance measurement data is needed to determine whether the AMN impedance characteristics are a realistic representation of the LV networks impedance over the full 2-150 kHz frequency range.

To enable supraharmonic regulation, there is a clear need to develop a measurement framework that must be robust, credible and acceptable to mass-market product manufacturers, PQ instrument manufactures, testing laboratories and grid utilities. The involvement of key WG conveners, a range of stakeholders and the close association of the project JRP Chief Stakeholder, is critical to smooth the path to timely new normative methods.