地区电网覆冰闪络跳闸脆弱性曲线及其应用

Vulnerability Curve of Ice Flashover Trips in Regional Grid and Its Application

极端冰灾天气下输电网群发性冰闪跳闸(ice flashovertrips,IFT)故障是激发电网脆弱性、导致大面积停电的关键因素。针对目前电力系统缺乏重冰区IFT相关标准、无法量度电网IFT危害程度等问题,提出了地区电网IFT脆弱性曲线,用于揭示电网IFT的内在规律。根据不同覆冰阶段电网具有不同的冰闪特征,建立电网IFT典型模式,并进行了风险等级界定。考虑到气象因素的模糊特征,采用模糊理论进行预测冰况的风险识别。基于线路短期动态可靠性模型,分析了不同风险等级下电网的风险测度,并指出电网IFT存在风险等级跳跃问题,将会严重危害电网的运行安全。研究表明IFT曲线能够反映电网绝缘系统的覆冰脆弱特性,不同地区、不同设计标准下电网IFT脆弱性曲线的临界拐点将会不同,但曲线的总体发展趋势不变。该曲线从整体上界定了地区电网IFT严重程度与发展趋势,紧急情况下能够快速、有效地为系统运行人员提供电网IFT风险信息。

Ice flashover trips （IFT） occurred in group nature is the key factor in triggering grid vulnerability and resulting in large scale blackout. Considering lack of relevant standard and measurement of IFT potential harmfulness, the IFT vulnerability curve was proposed to reveal IFT inherent law of the local grid. IFT typical patterns and risk grades were established based on IFT features. Considering fuzzy characteristics of the weather conditions, risk identification of the forecasted ice was performed. Risk measurements under various risk conditions were evaluated based on the established reliability model. Furthermore, the problem of IFT risk grade leap was revealed, which could severely impact operational security of power grid. The results show that the curve can reflect the vulnerability of insulation system, and the critical points would be different in various regions. But the general trends would keep invariant. The curve could express the severity and development tendency of grid IFT in a local grid, and provide the risk information in emergency circumstances quickly and efficiently.