An Efficient Voltage Control Methodology in LV Networks Integrating PV Prosumers Using Distribution Transformers with OLTC

Abstract

Nowadays, in the low voltage (LV) electric distribution networks (EDNs), the Distribution Network Operators (DNOs) are encountering an increased ratio of the small-scale distributed generation units, mainly photovoltaic (PV) prosumers. The irregular behavior and uncertainty degree of the injected power in the EDN can cause high voltage variations with violations of the allowable limits. Thus, a two-stage methodology that can lead to efficient voltage control in the LV EDN integrating PV prosumers by using the facilities of the On-Load-Tap-Changer (OLTC)-equipped transformer from the electric distribution substation has been proposed. A real rural LV EDN having a penetration degree of 20% with the PV prosumers has been used to test the proposed methodology. An optimal control plan for the OLTC has been obtained, having as the main effect maintaining between the maximum and minimum allowable limits of the voltage at the level of each pillar, with minimum energy losses. Accordingly, using the methodology will void the impact of the intermittency associated with the PV prosumers during the day with the positive consequences on the operation of the LV EDNs.