Performance Evaluation of Distribution System Interconnected with Solar PV Plants Using DIgSILENT

Abstract

Many African countries, such as Botswana, receive high insolation that can be used to generate electricity. However, they still rely on thermal power generation and imports from neighbouring countries through various African power pools. Thermal generation methods result in an increase in carbon footprint. Therefore, in pursuance of the global climate change goals, the Government of Botswana has subscribed to allow all end users with the capacity to install solar rooftops and sell extra electricity to the power utility. These interconnections of solar PV plants to the grid are bound to bring challenges to the steady state system performance. This research, therefore, evaluates the performance of the integrated system focusing on the greater Gaborone distribution system (GGDS), where five government projects are being piloted. The study has adopted two scenarios by providing a performance comparative analysis between the system baselines to a solar integrated system using DIgSILENT Power Factory software. The system studies conducted include power flow, effects on voltage and line loading. This research found out that integrating PV plants to GGDS distribution network improves voltage profiles and a decrease in overall percentage loading of the feeders and interconnectors. However, some notes could only permit a limited loading. In conclusion, the implications of the effects of solar PV on the distribution system differ from one circuit to another; therefore, it calls for utilities to conduct an intensive network assessment for each particular feeder before interconnecting with solar.