The impact of energy saving apparatus on power quality

Power quality (PQ) is a highly topical issue. It has gained momentum over the last decade owing to the accelerated increase in loads sensitive to service quality, e.g. computers, industrial drives, communications and medical equipment, etc. From the PQ perspective, these loads are quite perverse since they are not only sensitive to poor service quality but are also responsible for affecting adversely the quality of power supply. To aggravate matters, a wide range of so-called energy saving devices are being installed, quite sparingly, throughout the low voltage distribution network; inside the customers´ premises. These are power electronics-based devices, which, once installed, will actually reduce the kWh consumption of the load to which the energy saving device is attached. However, the downside of this “energy saving” measure is that such devices achieve their objective at the expense of generating very considerable waveform distortion. In order to characterise the waveforms resulting from the operation of energy saving devices, these authors have developed a digital data acquisition system suitable for monitoring voltage and current waveforms and associated harmonic information over long time spans. A selection of PQ measurements carried out in circuit buildings containing energy saving devices is presented