Intra-Interval Security Assessment in Power Systems With High Wind Penetration

In real-time operations, the forecasts and dispatches are associated with the ending time instants of dispatch intervals, while the wind power variations during the interval are unknown. When a high-wind-penetrated system encounters large short-term wind variations, the intrainterval variations (IIVs) of wind power and generation ramping can lead to unsecured operating conditions inside of an interval, referred to as the intrainterval security (IIS) issue. The goal of this study is to reveal the IIS issue under high wind penetration and analyze its impacts. To this end, this study investigates the nature of the IIS problem based on the dispatch interval mechanism, reveals the nonlinearity of wind IIVs as the root cause of the IIS issues (regulation shortage and transmission overloads), and proposes an assessment tool for assessing such issues. The tool screens the worst-case wind IIVs and assesses the issues using severity indices. The tool also considers the spatial correlation among wind farms and demonstrates that the IIS issues still exist under such correlation. Simulations on the IEEE 118-bus system verify the effectiveness of the proposed tool and highlight the IIS risks in power systems with high wind penetration.