Abstract:
Modern power systems comprise diverse nonlinear components, and an increasingly large
number of low inertia renewable power sources necessitate the modernization of conventional power
system security measures. Contingency analysis (CA), a routine process for power system operators,
ensures grid security under unforeseen circumstances by identifying potential issues and enabling proactive
measures for uninterrupted power flow. Electromechanical oscillations (EMOs) in the power system that
are a threat to stability must be regularly monitored and mitigated. An online hierarchical EMO index
integrating time and frequency response analysis can be utilized for system stability assessment. The
integration of an EMO index threshold into contingency analysis is presented in this paper to enhance
system security. This new approach is referred to as the stability-constrained contingency analysis (SCCA).
Typical results for a modified two-area, four-machine power system with large solar photovoltaic plants
simulated on a real-time digital simulator (RTDS) are presented. These results demonstrate that SCCA flags
potential issues that can arise from EMOs for certain contingencies, whereas traditional CA does not, as it
solely considers bus voltage limits and line ratings.
