考虑N-1安全网络约束的输电网结构优化

Optimal transmission switching considering N-1 security network constraints

输电网结构优化是控制输电阻塞的手段之一。且当负荷处于较低水平、系统裕度较高时,也可以通过结构优化提高设备的利用率。为了在开断部分线路的同时保证系统安全性,建立考虑N-1安全网络约束的输电网结构优化模型。通过对可开断线路潮流方程进行线性化,将原有模型转化成混合整数线性规划形式。为了应对负荷的短期波动及风电出力不确定性对电网结构优化结果的影响,采用吸引子传播(AP)聚类算法构建不同的运行场景。以修改的IEEE-RTS 24节点系统为例对所提模型进行验证和分析,结果表明,在满足一定的安全约束条件下,断开某些输电网线路可以减轻输电阻塞、降低系统的运行成本、提高线路的负载率水平。

OTS （Optimal Transmission Switching） is a way to handle transmission congestion and to improve the utilization rate of device when the load is in a low level and the system has a high security margin. In order to ensure the system security when partial lines are switched off, an OTS model is built with the consideration of N-1 security network constraints, which is converted into a mixed integer linear programming formulation through the linearization of power flow equations for switchable lines. AP （Affinity Propagation）is adopted to construct different operation scenes for dealing with the impact of short-term fluctuation of load and uncertainties of wind power on OTS. The modified IEEE-RTS 24-bus system is taken for an example to verify the proposed model, and results show that the transmission congestion and system operation cost can be reduced and the load rate of transmission lines can be improved by switching off some lines with the satisfaction of a certain security constraints.