Contingency set partition-based impact transfer approach for the reliability assessment of composite generation and transmission systems

摘要

It is a challenging task to obtain accurate reliability indexes with high computational efficiency for the reliability assessment of composite generation and transmission systems. A contingency set partition-based impact transfer (CSPIT) approach is proposed in this paper. The CSPIT consists of two stages. In the first stage, a contingency set partition technique is developed to combine the merits of the contingency enumeration method and the Monte Carlo simulation method to obtain accurate reliability indexes with higher efficiency compared to the two traditional methods. With this technique, the contingency set is partitioned into the lower-order contingency subset and the higher-order contingency subset. Then, the contingency enumeration method is applied to enumerate all lower-order contingencies, and the Monte Carlo simulation method is utilized to take samples from the higher-order subset. A new reliability index formulation for the technique is also derived. In the second stage, an impact transfer technique is developed to further improve the computational efficiency. With this technique, the derived formulation in the first stage is modified by transferring partial impacts of higher-order contingencies to the corresponding lower-order ones. The impact transfer reduces the impact variance of higherorder contingencies and thus improves the sampling efficiency of the technique proposed in the first stage. Finally, the reliability index computation flow for the entire CSPIT approach is demonstrated. The CSPIT approach is validated using RTS-79 and IEEE-145 test systems. Study results indicate that our approach can obtain accurate reliability indexes with much higher computational efficiency compared with traditional methods.