Impact of Grid-Scale Solar Photovoltaic Integration on Power System Performance

The impact of SPV integration on grid performance is a topic of ongoing debate, with conflicting reports on its effects. This study employs modal analysis, Newton-Raphson power flow, and time-domain simulations to assess the impactof SPV integration on voltage profiles, active power loss, and system stability in the IEEE 4-machine and Nigerian 50-bus power systems. The findings reveal that SPV integration impacts power systems differently, emphasizing the need for a comprehensive approach consideringvoltage stability, power losses, and stability constraints. While SPV integration can improve voltage levels and reduce power losses, it may also compromise transient stability, highlighting the importance of careful planning and grid reinforcement. For the IEEE 4-machine system, SPV integration is feasible up to 25% based on power loss, but transient stability constraints limit it to 0%. The Nigerian grid, achieves optimal SPV integration at 10% based on power loss and voltage profile, while transient stability constraints limit integration to 5%. This study underscores the necessity of a multi-metric approach to defining SPV penetration limits, considering the trade-offs between voltage performance, power loss, and system stability.This is an open-access article under the CC BY-SAlicense.Keywords:Solar energyTransient stabilityRenewable integrationPenetration limitPower system performance1.INTRODUCTIONRenewable energy (RE) sources, including solar, wind, and hydro, have the potential to become leading global energy sources, with targets to reduce CO2 emissions by 45% by 2030 and achieve netzero by 2050 [1]–[6]. Despite this potential, countries like Nigeria underutilize RE, especially solar. Advances have made solar energy more affordable, encouraging consideration of main grid integration as photovoltaic (PV) systems expand beyond distribution networks[7]. Optimal Distributed Generation (DG) placement has been shown to reduce technical losses and enhance voltage and power quality[8]–[11].The effects of large-scale solar photovoltaic (SPV) integration on power system security and reliability remain debated[12]–[16]. Kumar et al.suggest integrating grid-tied SPV with energy storage and MPPT control to enhance stability and cut generation costs[17], while Patnaik et al.advocate for innovativemanagement systems to stabilize the grid and reduce fossil fuel use[18]. Hossain et al. highlight the need for better control strategies for high PV penetration in low-voltage systems[19]. Peprah et al. find that rooftop PV can significantly lower distribution losses while maintaining standard voltage levels[20]. Adewumi et al. note that integrating Energy Storage Systems (ESSs) can improve voltage compliance with grid codes[21], while Sanni et al. point to grid weaknesses when integrating inverter-based generation in Nigeria[22].Saidi [23]and Ugwuanyi et al. [24]recommend using STATCOM-based strategies to address voltage stability in high-PV systems. Although SPV has been linked to improvements in transient and voltage stability[25][26], studies primarily focus on small-signal analysis, leaving the broader impacts on stability uncertain. Varying reports on RE impacts arise from different case studies and inappropriate integration, with most