Power quality monitoring for electric substation ancillary services supplying

Power quality is the study of the sources, effects and control of disturbances which propagate via the electric power supply. The disturbances change the supply RMS voltage or its waveform (or very occasionally the frequency) and may originate from various sources. Within the paper, the authors are focusing on power quality monitoring. The presented approach refers to substation ancillary services power supply from the autotransformer tertiary winding. The voltage is the main qualitative element, influencing the proper operation of the consumers. That is why its quality practically defines the power quality. A real case study is discussed. Various electric quantities have been monitored. The results are discussed and the appropriate conclusions are highlighted.