基于保护实时故障模型的电网脆弱环节在线辨识

On-line identification of vulnerable links in power grid based on protection real-time fault model

电网脆弱环节的及时有效辨识对预防系统大停电事故的发生具有重要意义。为了实现这一过程,提出了基于保护实时故障模型的脆弱环节在线辨识方法。根据保护设备历史统计信息与时间连续状态离散的Markov过程建立保护时变故障概率模型,在此基础上计及电网实时运行条件,合理量化了保护误动概率与拒动概率变化情况。根据故障传播特性模拟线路故障发生时的保护故障与动作方式,建立保护故障事件集,并应用风险理论结合保护故障概率与故障后果定义了保护故障脆弱度,衡量了保护故障对电网脆弱性的影响,以此辨识系统脆弱环节。算例结果验证了该方法的有效性与合理性。

Timely and effective identification of vulnerable links in power grid is important to prevent the occurrence oflarge-scale blackouts. To achieve this process, an on-line identification method of vulnerable links based on the real-time fault model of protection was proposed. A probability model of protection fault was established according to histor-ical protection system statistics and continuous time discrete state Markov process, and on this basis, quantifying thereal-time probability of failure to operate and undesired trip of protection reasonably by considering real-time operatingconditions of power grid. The protection fault events was established by simulating the protection fault and operationmode according to the spread characteristic of failures, and defining the protection fault vulnerability by applying risktheory to combine the probability of protection fault with the consequences of fault, weighing the impact of protectionfault on the grid vulnerability, thus the system vulnerable links can be identified. The simulation results demonstratethe effectiveness and rationality of the method.