Combined Effect of Temperature and Humidity on Distorted Currents Measured by Rogowski Coils

The necessity of accelerating towards carbon neutrality has been further pushed in recent times. Therefore, with the aim of developing smart grids, new Intelligent Electronic Devices (IEDs) are being widely installed. In this regard, Low Power Current Transformers (LPCTs) are replacing traditional inductive current transformers (CTs). Among these, Rogowski coils feature high linearity, reduced dimensions, and wide bandwidth in comparison to CTs. Hence, this work presents a study on a particular type of LPCT, the Rogowski coil, which is extensively used nowadays. In detail, temperature and humidity are simultaneously applied to three commercial Rogowski coils when measuring off-nominal, hence distorted, currents. The LPCTs performances are evaluated in terms of power quality indexes, Total Harmonic Distortion (THD) and single harmonic evaluation. From the results, THD is not significantly affected by the combined temperature/humidity presence. However, a deep analysis on the single harmonic demonstrated how they are strongly correlated to such influence quantities. It is interesting to highlight that each of the three devices under test present different behaviors. It is then crucial to in deep the investigation on the influence quantities affecting LPCTs. Furthermore, International Standards should include new details and test procedures to assess the effect on the LPCTs accuracy due to such quantities