Impact of the solar photovoltaic (PV) generation on long-term voltage stability of a power network

Power system voltage stability is of paramount importance to maintain a secure and reliable power network with high penetration of renewables. This paper investigates the impact of the solar photovoltaic (PV) generation on long-term voltage stability of a power network. Long-term voltage stability is investigated using the Nordic-32 bus test network comprised of dynamic models of automatic voltage regulators (AVRs), overexcitation limiters (OELs) and on-load tap changing (OLTC) transformers combined with static and dynamic loads. The investigation is conducted using an aggregated solar-PV system operating at voltage control mode under various loading conditions. A systematic approach has been followed for solar-PV integration. The results show that solar-PV systems enhance the long-term voltage stability of a stressed transmission grid when they operate under low loading conditions due to the improved reactive power support provided by solar-PV systems.