COMPREHENSIVE EIGENVALUE-BASED ASSESSMENT OF ROTOR ANGLE STABILITY IN NIGERIA'S 330 KV POWER GRID

Rotor angle stability is a crucial aspect of reliable power system operation, especially in developing countries where grids are weakly interconnected and face rapid load fluctuations. This paper presents an in-depth small-signal stability assessment of the Nigerian 330 kV, 36-bus, 13-generator power network via a detailed linearized state-space model based on eigenvalue modal analysis. Three control scenarios; no controller, governor only, and combined governor with power system stabilizer (PSS)—are examined across incremental loads using nonlinear differential-algebraic equations linearized by Taylor series expansion. Governor + PSS control significantly improves damping, stabilizes critical eigenmodes, and ensures satisfactory settling times. This study identifies nodes requiring additional control tuning and offers insights applicable to similar developing grid systems