Transient Stability Evaluation of 132kV Transmission Network for Improved Power Quality

Abstract

Transient instability in the power system leads to voltage collapse and consequently outages. This paper proposed the formulation and use of a 4th-order Runge-Kutta and a conventional swing equation for the 132 kV power transmission network from the Afam generating station to the Port Harcourt main (zone-2) injection substation. The initiated faults are not expected to last longer than necessary in the occurrence of a fault. This means that relays must provide automatic signaling communication to dedicated protective devices for isolation to avoid system interruption and breakdown. Numerical data were collated from the Transmission Company of Nigeria (TCN) to analyze the study case under investigation. The electrical transient analyzer tool (ETAP) was used to model and simulate the given preset value circuit breaker and relay time setting of 0.00, 0.02, 0.04, 0.06, 0.10, 0.12, and 0.14, respectively, on the view to investigate and evaluate parameters of rotor angle (δ), angular speed (w), and rotor-differential change (dδ/dt). The protective relay to coordination considered 10-cycle operation to the relay time setting of t=0.2 seconds, which must be responsive to clear faults as quickly as possible to enhance reliable power supply. The obtained results vividly indicate that the fourth (4th) order Runge-Kutta numerical technique tends to restore fault conditions and become stable and accurate with a fast response time of 0.02 seconds. It provides a lower absolute error of - 51% with power transfer capability from 0.00 pu to 3.7870 pu. This significantly means that the relays/protective device actions to system abnormal condition restoration time for stability were adequate during transient behavior as compared to other numerical solutions (modified Euler technique, etc.) for power system evaluation and analysis.