Power Quality Meters Based on Digital Inputs: A Feasibility Study

Modern power systems are experiencing a rapid transition towards a fully digital monitoring and control paradigm. In compliance with the specifications of the IEC 61850 standards family, measurement data shall be output by non-conventional instrument transformers according to the Sampled Value (SV) communication protocol. It is thus reasonable to expect that also Power Quality (PQ) measurements shall rely on SV data streams. Furthermore, due to the limited sampling frequency values considered in the standard, it is essential to evaluate the impact of different samples per cycle or packet loss conditions while detecting a PQ event. This paper investigates the feasibility of a PQ meter specific for voltage dips detection based only on SVs. To this end, a prototype hardware and software architecture is presented and characterized in standard and real-world test conditions. An experimental validation against a commercial device confirms the potential of the proposed SV-based PQ meter and the performance dependence on SV data stream integrity.