Implications of equipment behaviour on power quality

The vast majority power quality disturbances occur as a result of the interaction between the current flowing in a network and the impedance of the network. In this chapter the implications of the operation of a range of common equipment types on power quality is described. In the first instance, a technical description of the operating characteristics of common loads which are connected to electricity distribution systems is provided. Subsequently, a description and the characteristics of common power system loads is provided and where applicable this includes waveforms and analysis of harmonic distortion spectra. An overview of the impacts of variation in the characteristics of the supply voltage on equipment performance has been provided in order to provide the reader with an indication of the implications of supply voltage characteristics on power quality performance. The chapter concludes by providing a summary of standards designed to manage the power quality emissions of power system loads.