Simulation and Analysis of Power SystemUnder Performance Single Generator Outage Conditions

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Reliable electricity supply can be disrupted by sudden failures such as generator outages, which simultaneously reduce active power generation and reactive power support, affecting bus voltage stability and equipment loading margins. This study evaluates the performance of a seven-bus power system—comprising a utility grid, two synchronous generators, step-up/step-down transformers, transmission-distribution lines, and aggregated loads—under single generator outage conditions using the Electrical Transient Analyzer Program (ETAP). Newton–Raphson-based load flow analysis was conducted for three scenarios: normal operation, Generator 1 outage, and Generator 2 outage, in accordance with the N-1 contingency criterion. Results show that the Generator 1 (15 MVA) outage reduces load-bus voltages by up to 2.26% and raises Generator 2 loading from 67.8% to 97.3%, while all bus voltages remain within the permissible range of 0.95–1.05 pu. In contrast, the Generator 2 (20 MVA) outage produces a more severe impact, with voltage reductions of up to 3.19% that violate the lower voltage limit at two distribution buses, Generator 1 loading rising to 96.8%, and utility grid import more than doubling from 8.75 MW to 23.7 MW. These findings indicate that the system satisfies the N-1 reliability criterion for the Generator 1 outage but not for the Generator 2 outage, highlighting the need for additional reactive power compensation at the affected buses. The study also confirms that ETAP 19.0.1 provides an accurate and computationally reliable platform for N-1 contingency analysis, offering practical insight for power system planning, operation, and reliability assessment.