Analysing Voltage Stability Challenges Under High Photovoltaic Penetration in Niger' s Electrical Grid

The integration of solar photovoltaic (PV) power plants into the electricity grid offers a sustainable solution to meet rising energy demand, particularly in regions with abundant solar resources like Niger. However, high PV penetration introduces challenges to grid stability, including voltage fluctuations, increased power losses, and line overloading. This study investigates the impact of substantial PV integration on the voltage stability of the Nigerien River Zone (RZ) grid, which accounts for approximately 68% of the country's total energy consumption. Using quasi-dynamic simulations, the study examines grid performance across three selected months, viz., January, May, and August, to capture both daily and seasonal variations in demand and PV generation. Results reveal that periods characterized by peak demand and diminished PV output exhibited the most pronounced grid stress, with significant voltage deviations, increased power losses, and marked changes in the Voltage Stability Index (VSI). In August, frequent cloud cover leads to intermittent PV generation and increased variability, whereas May demonstrates relatively stable conditions during early afternoon hours. Key challenges include voltage instability during high demand, persistent overloading of major transmission lines, and heightened power loss linked to renewable variability. Recommendations include targeted interventions such as grid reinforcements, advanced reactive power support, energy storage systems deployment, and demand-side management strategies to enhance grid reliability. This study provides novel insights into the dual challenges of high demand and renewable variability, offering practical guidance to support Niger's transition to sustainable and resilient energy system.