Voltage regulation optimization in low voltage network based on Voltage Quality Index

The paper deals with an optimization procedure in terms of a network voltage parameters improvement. A software based approach is used to select optimal type of voltage regulator, its power and ideal location for application in a Low-Voltage (LV) test network, where it is required to enhance Voltage Quality (VQ). The test network presents a case where application of on-load tap changer transformer instead of conventional distribution transformer MV/LV is not adequate to maintain voltage profile in the LV system in limits. Therefore other type of voltage regulator has to be employed to increase VQ in the entire LV network. Principal measure for VQ evaluation there is adopted a Voltage Quality Index expressing the VQ level in dependence on selected and specified input parameters, which may be voltage magnitude, unbalance, harmonic distortion, flicker level and frequency. Within optimization process, maximal current carrying capacity of lines, network losses and cost of solutions are also taken into account.