Impact of distribution network voltage rise on PV system energy yield

Economic viability is one of the important factors in determining the rate of customer adoption of photovoltaic (PV) systems. A decrease in energy yield reduces their viability. At times of high PV production and low electricity demand, network voltage rises and may exceed limits resulting in a consequent curtailment of PV generation and reducing the energy yield. In this paper, a computational sequence was developed to investigate the impact of voltage rise at different nodes of the network on PV systems' annual energy yield for different PV penetration scenarios. The results of analysis conducted for Newcastle upon Tyne using UK generic urban distribution network are presented. It was found that the use of monthly averaged PV generation profiles resulted in the most optimistic PV system annual energy yield estimates. These profiles were under scenarios of very high PV penetration in the distribution network. A closer assessment of the PV generation profiles showed that there is a substantial number of days per year with high PV generation and therefore a large PV power curtailment may result unless adequate measures are put in place to capture maximum PV energy.