Sensitivity Based Thevenin Index for Voltage Stability Assessment Considering N-1 Contingency
This work addresses the need for efficient voltage stability assessment under contingency for power system operators, but the approach is incremental as it extends existing Thevenin index methods with sensitivity-based estimation.
The paper proposes a sensitivity-based Thevenin index (STI) to assess voltage stability under N-1 contingency by estimating post-contingency operating points. Numerical results on the IEEE 14-bus system demonstrate accurate prediction of voltage stability margins with low computational cost.
This paper proposes an approach to address the voltage stability assessment (VSA) considering N-1 contingency. The approach leverages the sensitivity based Thevenin index (STI) which involves evaluating the Jacobian matrix at current operating condition. Since the N-1 contingency case is hypothetical, there is no information regarding the operating condition after a foreseen contingency. The proposed approach first estimates the post-contingency operating point as well as possible PV-PQ transitions based on the current operating point. Then the STI for each contingency can be predicted using the estimated operating condition. Numerical results based on IEEE 14-bus system demonstrate the accuracy of the proposed approach in predicting the voltage stability margin under contingency. Moreover, the on-line implementation of the proposed approach is promising since it only involves solving several linear equations.