Rapid Voltage Changes in Power System Networks and Their Effect on Flicker

A rapid voltage change (RVC) is a type of power-quality (PQ) disturbance that has not received sufficient attention in the international PQ standards. Presently, EC 61000-4-30, Ed. 3, defines a precise method for RVC detection and analysis. RVCs can cause or contribute to flicker. However, the existing studies on the subject have not found a correlation between the short-term flicker severity index Pst and the parameters of an RVC event. This paper provides an interpretation of this lack of correlation and shows that instead there is a correlation of RVC events with the instantaneous flicker sensation Pinst. This work is based on the analysis of both simulated waveforms containing RVCs and waveforms recorded in low-voltage and medium-voltage locations.