Transient Stability Analysis of Nigeria 330kv Power System Network Using Numerical Method: A Case Study of Calabar, Alaoji and Afam 330kv Network

Abstract

Instability constitutes part of the major challenges in the power system industry as a result of the increase in the complexity of power system networks. Electric energy demand keeps increasing while the expansion of electrical power generation and transmission is faced with severe challenges due to some factors which range from loss of synchronization as a result of some contingencies on the network. This study analyzes the transient stability of the Nigeria 330KV sub-network (Odukpani, Alaoji and Afam) with its analysis performed using MATLAB software to simulate a 3 - phase fault on the network to determine the fault clearing time of the system. The results obtained show that the relative swing between the generator rotor angles is less when the fault clearing time is less with fault clearing time at 0.1, 0.2, 0.3 and 0.4 seconds respectively. By these, there is a tendency for the system will regain stability due to the swing within the stability limit of 0.1sec to 0.4sec with a critical clearing time of 0.45sec. For an unstable condition, the fault clearing time increases at 0.5, 0.6, 0.7 and 0.9 seconds respectively with the rotor angle of the generator increasing out of limit or out of step. Hence, for a system to be stable the fault that occurs should be cleared within a minimum of 0.1sec to 0.4sec which implies the lesser the fault clearing time the greater tendency for stable condition and vice versa.