Transient Stability Improvement on Power Network using Static Synchronous Compensator: A Case of The Nigerian 330 KV Electricity Grid

Abstract

This study deals with power system transient stability, enhanced via a static synchronous compensator (STATCOM). The system’s steady state and transient responses were modelled with Newton-Raphson-based power flow and modified Euler-based swing equation, respectively. Simulations were performed with and without STATCOM, considering the Nigerian 34-bus power grid. A balanced three-phase fault was used for the transient stability analysis. The voltage magnitudes of Katampe (0.9373), Kaduna (0.9209), Kano (0.9381), Jos (0.8295), and Gombe (0.7795) in the grid violated the statutory voltage limit of 0.95 to 1.05 p.u. before compensation and were improved to 0.9650, 0.9550, 0.9789, 0.9630, and 0.9550 p.u., respectively after STATCOM was applied. The system’s total real line losses before and after compensation were 57.887 and 55.623 MW, respectively. Fault application on bus 20 (Akangba T.S) caused loss of synchronism on generator 14 when the critical fault clearing time (CFCT) exceeded 0.019 s while generators 2 to 13 experienced marginal stability. The STATCOM application restored stability beyond the CFCT of 0.019 s due to compensation provided by the device. Fault introduction on bus 22 drove Egbin, the largest system’s generator corresponding to generator 7 on the swing curve into marginal stability along with generators 3 to 6 and 8 to 14 while generator 2 lost synchronism beyond a fault CFCT of 0.0130 s. However, the STATCOM application restored the system’s stability. STATCOM aided the transient stability improvement of the Nigerian 34-bus power network for effective operation.