冰灾天气下输电网覆冰闪络跳闸风险评估

Icing Flashover Trips Risk Assessment of Transmission System in Ice Disaster Weather

冰灾天气下输电网覆冰闪络跳闸(Icing Flashover Trip,IFT)故障是激发大电网脆弱性、导致大面积停电的主要原因,对电网IFT等问题的研究是制定电网抗脆弱性策略的基础。对冰灾天气下输电网IFT风险进行了定性与定量分析。定性分析阶段,提出了电网IFT特征曲线,界定了电网各覆冰阶段IFT特性。进一步建立了电网IFT状态指标,采用模糊模式识别方法对预测冰况进行风险评级。基于此,运行人员能够从整体上掌握电网IFT严重程度与发展趋势。定量分析阶段,考虑到电网IFT数据的小样本特征,采用了结构风险最小化小样本建模方法。考虑到IFT强迫停运率受冰况影响,提出了强迫停运特征因子。通过对电网可靠性分析,计算出具体的量化指标,动态识别电网薄弱环节,并给出电网IFT特征曲线各阶段(风险状态)下指标的分布特征。

Icing Flashover Trip （IF＇F） is the key factor in stimulating power grid vulnerability and causing blackout. IFT risk analy- sis is the basis of making resistance vulnerability strategy. Qualitative analysis and quantitative analysis are carried out in this study. In stage of qualitative analysis, Grid IFT characteristic curve is proposed to be used to reflect grid IFT features. Furthermore, IFT state indices are established, and risk grade of forecasted ice conditions is identified by fuzzy theory. The serious degree and develop- ment tendency of grid IFT could be understood as a whole in qualitative analysis stage. In stage of quantitative analysis, considering small sample characteristic of the data, Structural Risk Minimization modeling method is adopted. In view to forced outage rate influ- enced by ice conditions, forced outage characteristic factor is proposed. Quantitative indices are calculated, and grid weak points could be identified dynamically. In addition, indices distribution features of each risk grade in qualitative stage are presented.