Impact of large-scale distributed photovoltaic integration on distribution network voltage

The large-scale integration of distributed photovoltaic (PV) systems into distribution networks has led to increasingly significant impacts on network voltages, presenting both opportunities and challenges for grid operators. This paper provides a comprehensive analysis of the principles of distributed PV grid integration and its influence mechanisms on distribution network voltage. Through detailed theoretical derivation and simulations based on the IEEE 33-node system, the effects of different PV integration locations and capacities on voltage distribution are thoroughly investigated. The results indicate that integrating distributed PV can effectively elevate node voltages, thereby mitigating issues of undervoltage, a common problem in long feeders. The improvement in voltage stability is more pronounced when PV systems are connected closer to the feeder end or at nodes with inherently weak voltage profiles. Furthermore, increasing the PV capacity leads to a more substantial voltage rise at end nodes due to their higher sensitivity. However, a critical finding is that the concentrated integration of PV systems on a limited number of branches, while beneficial for the localized branch, can easily cause local voltage limit violations and does not uniformly address undervoltage across the entire network. Conversely, a more distributed integration pattern improves voltage profiles across multiple branches but may provide less targeted support to the weakest nodes. This study underscores the importance of strategic siting and sizing of distributed PV systems and provides a theoretical foundation for their rational planning, operation, and the development of effective voltage control strategies in modern distribution networks.