Prevention of distribution network overvoltage by adaptive droop-based active and reactive power control of PV systems

•Overvoltage in distribution networks with high penetration of PV systems.•Adaptive reactive power control for loss minimization and overvoltage regulation.•Local adaptive active power curtailment of PV systems for overvoltage suppression.•Effectiveness of the proposed algorithms is determined by simulations.

Proliferation of grid-connected photovoltaic systems (PVSs) causes technical problems due to their variable and non-dispatchable generated power. High penetration of PVS in distribution networks can result in overvoltage in some operating conditions. Although this situation occurs rarely, it limits the installed capacity of PVS. In this paper, adaptive droop-based control algorithms are presented to regulate active and reactive power of PVS, with the objectives of loss minimization and increasing the PVS capacity installation without unallowable overvoltage. Operating voltage range of the PVS is divided into several intervals, and a specific control algorithm is presented for each of them. Reactive power control of PVS is used as the first action, and active power curtailment as the final remedy for voltage rise prevention. The proposed adaptive droop-based algorithms make the system operation smooth and highly stable. The required active power curtailment is shared equally between all PVSs, so that they have equal opportunity to sell their extra generation. Decentralized control with only local measurements is the other feature of the proposed methods. Efficiency of the proposed methods is demonstrated through simulation of different scenarios on the IEEE 33-bus distribution network.