潮流转移诱导线路触树故障的时间与概率预测

Prediction of time and probability of line tree-related fault caused by power flow transferring

潮流转移诱导的线路触树故障是造成电网连锁性事故的重要原因之一,预测线路触树故障时间和概率是防止系统灾变的关键。在综合考虑树木生长、环境条件、潮流变化,在提出各影响因素定量刻画方法的基础上,提出一种预测线路触树故障时间和概率的方法。结合环境因素的随机性和线路潮流变化量,用近似线性化算法确定线路的热时间常数,通过触树故障时间概率密度函数,预测触树故障期望时间和初始故障后任意时段内线路触树概率。仿真证明,触树时间与概率主要取决于稳态电流和所处环境,当潮流剧烈变化时,本方法可及时获得各层故障路径中线路发生触树故障的时间和概率,为调度人员及时采取安全措施提供了决策依据。

Tree-related failure caused by large-scale power flow transferring is one of the most important causes of power grid catastrophic accident. Predicting the flashover time and probability after the later tripping is an important subject to prevent system blackouts. Considering dominant vegetation growth, circumstance and power flow transferring, quantitative depicting method for the influencing factors and prediction method of line fault probability and time are proposed. Combining the randomness of influencing factors and power flow, an approximate linearization method is used to determine line heat time factor. With the help of probability density function of line contacting tree, line contacting tree time and probability is predicted. Two cases simulation results show that the contacting time and probability mainly depend on line final steady state power and circumstance factors. When the line power flow is changing tempestuously, the proposed method can predict the tree-related fault time and probability in time. These results can provide reasonable decision-making for power system operators to prevent power system blackout.