Strengthening the Nigerian Grid: Impact of SCR Thresholds on Synchronous Condenser Allocation for Inverter-Based Generation Integration

Abstract

Energy-constrained power grids increasingly rely on inverter-based generation (IBG) from solar photovoltaic (PV) and wind sources to supplement their power supply needs. However, these alternatives lack inherent grid-supporting capabilities like short-circuit current and reactive power, which are vital for system stability. Consequently, their integration weakens system strength. Grids require a minimum system strength threshold to maintain adequate strength and successfully accommodate IBG. This paper investigates the allocation of synchronous condensers (SCs) to enhance the short-circuit ratio (SCR), a key indicator of system strength, within the context of the Nigerian power grid. With an SCR threshold of 5, SC allocation using genetic algorithm (GA) optimization effectively improved SCRs at vulnerable points of interconnection (PoIs), notably Katsina and Jos. For a stricter threshold of 10, larger SCs were needed across two more PoIs at Kano and Gombe, achieving significant SCR improvements. We demonstrate that SCs can effectively increase short-circuit current and reinforce system strength at strategic grid points. The findings provide valuable insights and lay the groundwork for further research into the implications of SC deployment for grid resilience and large-scale integration of inverter-based generation.