Transient stability assessment application using post-disturbance voltage fluctuations in a multi-machine power system

Transient stability analysis programs are typically based on step-by-step numerical integrations of power-system models to simulate system dynamic behaviors. Unfortunately, these approaches are inadequate for dealing with the changing overall system conditions. For years, direct methods have held the promise of providing real-time stability assessments; however, they have presented several challenges with rotor angle-based theories. The angle-based common reference, such as the center of inertia, must be updated in each measurement instant, and this calculation requires the connectivity status of all generators. In addition, the field-angle difference data can suffer from errors, and an ex-post analysis needs many phasor measurement units. This study addresses these challenges with novel methods provided with voltage-based theoretical foundations because voltage is an easily available information. The proposed method monitors or simulates the post-disturbance voltages and calculates the product voltage deviation and rate of voltage change as an indicator of the post-disturbance transient instability. A relationship between the proposed index and the transient stability in a multi-machine power system is formulated, and the method effectiveness is tested through a simulation on a New England power system.