The article presents a System Research activity which involves, in addition to RSE, the main Italian Research Institutes involved in the study and modeling of measurement transformers, in particular the National Institute of Metrological Research – INRiM, the CNR, the Politecnico di Milano and the Universities of Campania Luigi Vanvitelli, Bologna, Cagliari and Palermo.
The activity is aimed at compensating for the non-linearities and distortions introduced by the measurement transformers, in particular those based on inductive technology, to improve their accuracy in the context of Power Quality measurements in Medium and High Voltage, thus expanding the field of application compared to the traditional industrial frequency measurement and protection.
This compensation can be implemented using models of the behavior of the measurement transformers in an advanced version of the Stand-Alone Merging Unit (SAMU); these devices were originally conceived to digitize the analog signals coming from the measurement transformers and make them available on the system bus in IEC 61850 format, and therefore a widespread diffusion is expected: it is therefore natural to hypothesize equipping them with additional functions.
The potential future impacts of the activity include in particular the development of innovative methodologies for the characterization and calibration of measurement transformers, so as to allow their execution in the field with specific equipment. The benefits obtained from improved accuracy at the local level could therefore be extended to neighboring nodes, also implementing PMU functionality in S-SAMU3 and adopting a distributed approach to improving the accuracy of measurement systems.