Towards an EMC Coordination for Interharmonics in Public Low Voltage Networks

Electromagnetic compatibility (EMC) is an essential requirement for the disturbance‐free operation of equipment connected to electricity networks. The process of EMC coordination always starts with a detailed characterisation of the interference mechanism that has to be protected. Based on this characterisation, appropriate indices for the quantification of the mechanism have to be introduced. Finally, based on these indices, compatibility levels, immunity testing procedures, including test levels and emission limits, are established that form the best possible trade‐off of sharing costs, risks and responsibilities between all involved stakeholders. Recently, flicker in LED lamps caused by interharmonic distortion was identified as a new interference mechanism which is not yet covered by the existing EMC coordination in the IEC 61000 series of standards. This article proposes a novel EMC coordination framework to address this interference mechanism. It shall serve as information for standardisation committees in IEC TC77/SC77A and IEC TC34 to extend or update the relevant standards. The article follows the process for EMC coordination for this new mechanism, starting from a detailed characterisation of it, proceeding to define suitable indices and measurement methods to capture it and finally proposing compatibility levels, immunity testing procedures, test levels and emission limits.