基于支路等值的拓扑辨识方法

状态估计中拓扑辨识是一个疑难问题,很多拓扑辨识方法把开关状态作为未知量引入估计过程,对量测冗余度和精度提出了较高要求,加大了状态估计辨识可疑数据的难度,工程应用困难。通过支路关联遥测遥信互校,确定运行状态可疑的支路。状态可疑支路在状态估计中作为参数未知支路,只需要引入一个状态变量,从支路参数计算结果就可判断支路运行状态,并给出了支路电导引入信息矩阵方法。正确判断支路运行状态后,利用状态估计节点电压计算支路潮流并修正两端节点注入,就可得到完整的电网运行状态,无需重新状态估计。该方法可以辨识小潮流支路拓扑错误。测试结果表明,由于在常规PQ解耦状态估计引入未知量,只增加一维状态量,计算速度快,拓扑辨识结果准确,适合在在线系统中应用。

A topology estimation method based on branch equivalence

The topology error identification is a puzzle in state estimation, new state variables representing breaker status are introduced in topology estimation, which is rigorous for demanding higher precision of measurements and makes it difficult for bad data identification. Practically, these methods are not suitable for being applied in EMS. A new fast topology estimation method without introducing any new state variables is proposed in state estimation. In this method, all branches (line or transformer winding) with uncertain status are equaled to energy consumers and are identified by verifying the measurement consistency of power flow and associated breaker status. The status of suspected branches could be ascertained from the power flow results of equivalent energy consumers. The criteria of ascertaining branch status are offered. Once the status of a branch is detected, its power flow can be calculated using bus voltages of both sides. After power injections of all buses are modified, the whole states of power system can be achieved without carrying out state estimation again. This method is also effective to light load branches topology errors. The performance of the proposed method is assessed through its application to one of province EMS, considering different types of topology errors and distinct network configurations.