基于加权潮流熵的电网故障传播脆弱线路识别

为提高电力系统运行安全水平,提出一种基于加权潮流熵的电网故障传播脆弱线路识别方法。通过直流潮流法快速估算线路断开时系统其他线路的潮流增量及负载率,采用加权潮流冲击熵反映目标线路受其他线路断开的转移潮流的影响,利用加权潮流分布熵反映目标线路断开对系统线路负载率分布的影响。结合加权潮流冲击熵与加权潮流分布熵定义线路综合脆弱指标,识别电网故障传播中的脆弱线路。直流潮流法可通过简单的数学运算准确估算系统断线故障时各线路的潮流情况,计算量少,适用性好。该方法综合考虑线路的受冲击脆弱度和断开后果脆弱度反映线路在电网故障传播中的脆弱性,同时,加权潮流熵有效反映了线路负载率较高甚至过载时的危险性。在IEEE39节点系统中对该方法进行了验证。

Identification of Vulnerable Lines for Fault Propagation in Power Grid Based on the Weighted Power Flow Entropy

To improve the operation security level of power grid, an identification method of vulnerable lines for fault propagation in power grid based on the weighted power flow entropy is put forward. The DC power flow method is used to estimate the power increment and load rate of other transmission lines when line disconnection fault occurs. The weighted power shock entropy is used to reflect the effect of the power flow transferred from other disconnected transmission lines on the goal transmission line, and the weighted flow distribution entropy is applied to reflect the influence of the disconnection of the goal transmission line on the distribution of load rate in power system. By combining the weighted power shock entropy and the weighted flow distribution entropy, the comprehensive vulnerability index is defined to identify the vulnerable lines for fault propagation in power grid. The direct current power flow method can accurately estimate the line power when line disconnection fault occurs through simple mathematical calculating, which has such advantages as less computation amount and good applicability. Both the impacted vulnerability and the disconnected consequence vulnerability of transmission lines are used to reflect the vulnerability of transmission lines for fault propagation. At the same time, the weighted power flow entropy can reflect the risk of the high load rate even overload. In the end, the method is verified in IEEE 39\|bus system.