Characterization of a Low Power Instrument Transformer with Digital Output in Low-Inertia Power Systems

Based on the IEC Std 61850, electrical substations are transitioning towards a fully-digital paradigm for data acquisition and processing. In the near future, many monitoring and control applications are expected to operate based mainly on digital inputs. To this end, a crucial role will be played by the Low Power Instrument Transformer (LPIT) whose output is formatted as Sampled Value (SV) data packets according to the recent IEC Std 61850-9-2. In this paper, the metrological performance of a commercial LPIT is fully characterized not only in stationary conditions, but also in dynamic and distorted tests, inspired by the IEC Std 60255-118-1 for synchrophasor measurements and by real-world datasets of power systems characterized by reduced inertia. Based on the obtained results, considerations are drawn in respect of possible applications of SV data streams in measurement applications.