Stability-constrained contingency analysis for modern power systems

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.