计及短线路同杆并架双回线的输电网混合状态估计

A Hybrid State Estimation Algorithm for Transmission System Considering the Short Untransposed Double-circuit Lines

提出计及短线路同杆并架双回线参数不对称的输电网精确快速混合状态估计模型及算法。首先通过机理分析获得导致输电网采用单相状态估计进行包括短线路不换位同杆并架双回线估计时,短线路不换位同杆并架双回线中无功功率估计与其实际量测值偏差大的原因:双回线之间因自感和互感不相等导致参数不对称;并用仿真方法分析其传输功率差的影响因素。基于所得到的上述原因,提出实现输电网中短线路不换位同杆并架双回线无功功率准确估计须采用三相状态估计方法。进而提出基于Π型等效接口的输电网单三相混合状态估计的快速算法及Π型等效接口位置自动确定策略。采用IEEE118系统对模型的机理、模型及算法的可行性和有效性进行分析验证。

The paper proposed a fast and accurate hybrid state estimation algorithm for networks with short, unsymmetrical double-circuit lines. By theoretical analysis, it was found that the cause of the significant estimation error of reactive power of double-circuit lines is that inequality of self-impedance matrix and of mutual-impedance matrix between them result in parameters asymmetry. By simulation analysis, the influence factors of the transmission power difference of the line I and II were found. It was concluded that in order to realize the precise transmission reactive power estimation of short, untransposed double-circuit lines, three-phase state estimation algorithm must be adopted. We further proposed a fast hybrid single-phase and three-phase state estimation algorithm using π equivalent circuit for the transmission network and a strategy of the automated determination of the location of the π equivalent circuit. Effectiveness and validity of the theory analysis, the proposed model and algorithm was illustrated and demonstrated by the calculation results of IEEE-118 test system.