考虑线路负载率指标规划-运行协调一致性的电网规划双层模型

Bi-level Transmission Expansion Planning Model Considering Planning-operation Coordination of Line Load Rate Indices

随着新能源渗透率的提高,电力系统潮流的变化更加复杂,作为长期电力电量平衡的关键环节,电网规划的要求也逐渐提高。电网规划模型通常以网络传输容量上下限为约束,这可能出现某些线路长期处于重载运行的问题,增加了电力系统的安全隐患,因此在规划中需要关注负载率指标。考虑到在两阶段模型中添加年度统计指标约束会使所有场景耦合而无法有效反映系统实际运行情况的问题,分别设计了线路重载率约束以及改进直流潮流约束的线性形式,并建立了电网规划双层模型。上层问题为规划决策,用于制定规划方案,下层问题为运行模拟,用于对规划方案进行校核。相比两阶段模型,双层模型中的运行问题不会受到规划层约束的影响,能够真实反映规划方案下系统的运行情况。算例分析验证了规划中添加线路重载率约束的有效性以及双层模型结构的合理性。

With the increase in the penetration of renewable energy,the power flow changes have become more complex.As the key link of the long-term power and energy balance,the requirements to the transmission expansion planning(TEP)are also gradually being raised.The TEP usually takes the upper and lower limits of the transmission capacities as the constraints,which may lead to the problem that some transmission lines are always in the heavy load operation,increasing the security risks of the power systems.Therefore,the load rate indices need to be paid attention to in the TEP.Considering that adding constraints of the annual statistical indices to the two-staged model may couple all the scenarios so that the actual operation of the system cannot be effectively reflected,this paper designs the linear forms for the line heavy rate constraints and the improved DC power flow constraints,and establishes a bi-level TEP model.The upper-level is for the planning decision problem that is used to formulate a planning scheme,while the lower-level for an operational simulation problem that is used to verify the planning scheme.Compared with the two-staged model,the operation problems in the bi-level model is able to truly reflect the operation of the system under the planning scheme without being affected by the constraints of the planning level.The case studies verify the effectiveness of adding the heavy load rate constraints in the planning and the rationality of the bi-level model structure.