Measurement approach for monitoring voltage dips in HV and MV networks

Voltage dip is one of the power quality (PQ) problems that is causing major financial losses to industrial and commercial customers. To improve the quality of the network and to provide a supply voltage of sufficient quality, PQ monitors have been installed in the HV and MV networks. As the end-users are usually connected to the MV networks through Dyn transformers, measuring and then reporting dips based on the phase-to-ground measurement could result in unreliable information. In this paper, the transfer of voltage dips from the HV to the MV network, and then to the LV network is studied first. For phase voltage (field) measurements, improved ways of reporting dips are discussed. Then, better approaches of measuring and reporting dips are discussed, which bring a number of merits for the DSOs. The most appropriate measurement approaches are then proposed for monitoring dips in the HV and MV networks.