考虑N–1安全约束的输电线路投切缓解电压越限的电网拓扑优化方法

Network Topology Optimization Method for Relieving Voltage Violations by Transmission Switching Considering N–1 Security Constraints

提出了一种考虑N–1安全约束的输电线路投切缓解电压越限的电网拓扑优化方法。该方法主要包括筛选、排序、详细分析与评估以及N–1校验4个阶段来保证求解的速度与精度。所提出的方法依次执行快速识别有效候选线路、对其可靠性进行排序、详细分析排在前列的候选线路开断后系统的状态并给出一组能够缓解当前系统电压越限问题的线路开断方案。为了提高方案的质量,阶段3使用了Look-ahead法评估线路开断30min后系统的运行状态,并考虑N–1安全约束再次校验了解的质量。所提出的方法通过将线性方法与非线性方法相结合平衡了速度与精度之间的关系从而达到在线应用的目的。其特色在于能够提供一组高质量的线路开断方案以供系统运行人员选择。基于IEEE39节点系统及2746节点系统对所提的考虑N–1安全约束的方法的测试取得了令人满意的结果。

A network topology optimization method for relieving voltage violations by transmission switching considering N–1 security constraints is proposed. This novel online method is based on a four-stage strategy, including screening, ranking, detailed analysis and assessment, and N–1 check stage, to ensure fast speed and accuracy of solving. The proposed method performs the tasks of rapidly identifying effective candidate lines, ranking the effective candidates, detailed analysis of the top ranked candidates, and supplying a set of effective line switching solutions for current power system to relieve voltage violations. In order to improve solution quality, the state of the system after 30 minutes is predicted using a look-ahead method at stage 3, and the quality of the line switching schemes is checked again at stage 4. The proposed method balances speed and accuracy by combining linear and nonlinear methods to achieve the goal of online application. One distinguishing feature of the proposed method is that it provides a set of high-quality line switching solutions for operators to choose a preferred solution. Effectiveness of the proposed method considering N–1 security constraints is evaluated on the IEEE 39-bus and 2746-bus power systems with promising results.