Abstract
Distributed PV generation is an increasingly popular way of integrating renewable energy sources into the power system. High PV penetration can, however, lead to issues, particularly overvoltage in LV networks. To accurately evaluate when issues can occur, interactions between LV and MV networks must be considered, as the LV hosting capacity can be reduced by PV development in other parts of the network. This paper presents a coupled MV-LV model to study the interactions between networks with a high amount of PV generation. The MV-LV transformers are modelled with tap changers, further limiting the available PV hosting capacity, as tap positions are set to avoid undervoltage in winter. Hosting capacity is determined stochastically through Monte Carlo simulations of PV development, with results highlighting how PV systems affect voltages in neighbouring LV networks. LV networks with high transformer tap positions are particularly vulnerable to overvoltage and reduce the expected hosting capacity of the distribution network as a whole. In addition, a simple heuristic limiting PV penetration in each LV network based on tap position is implemented, improving the expected MV network’s PV hosting capacity by 250%, and reducing variance. This indicates a possible socio-economic utility of managing distributed PV development, through curtailment or other means.
