基于潮流转移因子的电力系统连锁跳闸风险评估

Power Flow Transfer Factor Based Risk Assessment of Power System Cascading Trips

提出了一种基于潮流转移因子的电力系统连锁跳闸风险评估方法。在基于最优潮流交易的基础上,应用潮流转移因子对支路切除后的潮流转移情况进行预测,考虑潮流转移后支路电流不确定性建立后备保护动作概率模型,用首条支路故障概率和下条支路后备保护动作概率之积描述连锁跳闸的可能性指标,以连锁跳闸后是否切负荷将风险严重性进行分级,然后分别以连锁跳闸后系统购电费用增幅和切负荷费用为严重性指标,从而得到特定交易下支路连锁跳闸风险值,获得高风险连锁跳闸的支路路径信息,为制定交易计划和防范风险提供决策支持信息。IEEE10机39节点系统算例仿真结果表明了该方法的有效性。

This paper presents an approach based on power flow transfer factor （PFTF） to assess the risk of cascading trips in power system. Based on optimal power flow （OPF）, PFTF is used to predict power flow transfer distribution after a fault transmission line is removed. The tripping probability model of backup protection is built when the uncertainty of branch currents is considered after power flow transfer, thus probability index can be obtained by the product of the failure probability of the first fault branch and the tripping probability of backup protection of next line. Severity levels of the risk are evaluated through analyzing the conditions in which whether the loads need to be shed, then the increase of pool purchase cost and the cost of load-shedding are chose as the severity indices. On the basis of the risk indices, information of cascading tripping branches with high risk can be identified, which can offer some supporting and decision information for arranging trade schedule and preventing risk. The numerical studies on New England 10-unit 39-bus system show that the proposed assessment method is effective.