Evaluation of the Impact of Photovoltaic Solar Power Plant Integration into the Grid: A Case Study of the Western Transmission Network in the Democratic Republic of Congo

Rising electricity demand and the need to reduce pollutant emissions highlight the importance of renewable energy, especially solar power. While most studies on photovoltaic (PV) integration focus on developed countries, least developed and developing countries such as the Democratic Republic of Congo (DRC) face particular challenges due to fragile grid infrastructure. This work evaluates the technical and operational impacts of PV integration into the western grid of the DRC using DIgSILENT PowerFactory 2021 SP2 simulations. It examines penetration levels from 10% to 50% based on a 2012 MW baseline, and evaluates power losses, short-circuit ratios (SCRs), grid stability, harmonic distortions, and voltage oscillations. Results reveal that moderate penetration levels (10–20%) reduce active power losses by 25% while maintaining stability. However, above 30% penetration, critical challenges arise, including a drop of the SCR below the minimum recommended value of 3, prolonged voltage oscillations, and increased harmonic distortions, resulting from the reduced overall inertia of the grid following the increase in PV power from inverters without inertia. These findings emphasize the need for targeted solutions like Battery Energy Storage Systems (BESSs), Static Synchronous Compensators (STATCOMs), and harmonic filters. This work provides foundational insights for PV integration in fragile grids of LDCs and developing countries.