Network voltage performance

The quality of electricity supply is considerably influenced by the quality of the voltage provided to customers, which can be affected in various ways. There may be long periods of variation from the normal voltage, sudden changes in voltage, rapid fluctuations, or unbalance of 3-phase voltages. In addition, other irregularities such as variations in frequency and the presence of non-linear system or load impedances will distort the voltage waveform, and transient spikes and surges may be propagated along circuits in a supply system.