Methods and Strategies for Overvoltage Prevention in Low Voltage Distribution Systems with PV

The rapid development of photovoltaic (PV) systems in electrical grids brings new challenges in the control and operation of power systems. A considerable share of already installed PV units are small-scale units, usually connected to low voltage (LV) distribution systems that were not designed to handle a high share of PV power.

This paper provides an in-depth review of methods and strategies proposed to prevent overvoltage in LV grids with PV, and discusses the effectiveness, advantages, and disadvantages of them in detail. Based on the mathematical framework presented in the paper, the overvoltage caused by high PV penetration is described, solutions to facilitate higher PV penetration are classified, and their effectiveness, advantages, and disadvantages are illustrated.

The investigated solutions include the grid reinforcement, electrical energy storage application, reactive power absorption by PV inverters, application of active medium voltage to low voltage (MV/LV) transformers, active power curtailment, and demand response (DR). Coordination between voltage control units by localized, distributed, and centralized voltage control methods is compared using the voltage sensitivity analysis.

Based on the analysis, a combination of overvoltage prevention methods and coordination between voltage control units can provide an efficient and reliable solution to increase the PV hosting capacity of LV grids. ½½