Comparative Performance of TCSC and Wind Energy Integration on Nigerian 48-Bus Grid Using Brown Bear Optimization and Genetic Algorithm

Abstract

Introduction: The Nigerian 330 kV transmission system faces persistent operational challenges, including high active power losses, voltage instability, and severe vulnerability to line contingencies, particularly at long, weakly compensated terminal corridors.

Objectives: This study comparatively evaluates series reactive compensation via a Thyristor-Controlled Series Capacitor (TCSC) against localized active/reactive power injection via a Wind Energy Conversion System (WECS) for loss minimization, voltage profile enhancement, and N-1 contingency resilience on the Nigerian 48-bus, 330 kV grid.

Methods: The 48-bus network (1 slack bus, 15 PV buses, 32 PQ buses, 79 lines) was simulated by Newton-Raphson load flow. Brown Bear Optimization (BBO) and a Genetic Algorithm (GA) independently sited and sized each device by minimizing a weighted objective combining normalized real power loss and a Voltage Deviation Index (VDI). All 79 lines were then screened for N-1 contingency severity under the base case and both compensated configurations.

Results: The baseline load flow gave active/reactive losses of 67.702 MW / 2,122.31 MVAr (VDI = 0.02618), with statutory violations at Sakete (0.9255 pu), Kano (0.9471 pu), and Jos (0.9495 pu). Wind integration (100 MW, 100 MVAr) at Sakete reduced active loss by 12.816% and VDI to 0.02170, restoring both Sakete and Jos to compliance. TCSC-BBO, sited on Line 31–33, reduced active loss by 0.396% and restored Sakete's voltage to 0.9576 pu; TCSC-GA, sited on the electrically distant Line 23 (11–13), reduced active loss by a comparable 0.589% but left Sakete's voltage effectively unchanged at 0.9255 pu. GA converged faster than BBO throughout, while both reached similar objective values. Screening identified eight critical N-1 contingencies — including the line carrying the TCSC — that neither compensation strategy resolved.

Conclusions: Localized wind-based active/reactive injection outperforms TCSC series compensation on this network for both loss reduction and voltage recovery, but neither single-device strategy addresses the network's underlying N-1 structural vulnerability, which requires multi-device planning or targeted reinforcement.