【作者】 王靖然；

【导师】 余贻鑫；

【作者基本信息】 天津大学 ， 电力系统及其自动化， 2011， 博士

【摘要】 大规模可再生能源的集中接入与特高压电网的建设对传统的电力系统规划提出了新的挑战,规划方案的拟订与评估决不应仅靠规划人员的经验,而必须依赖于高效的、系统化的方法。同时,近年来世界上发生的几起大停电事故使得如何系统化地评估电力系统规划方案的安全性成为亟待深入研究的问题。基于此,本文从全局和局部两个方面设计了输电网优化规划的寻优策略并对电力系统规划方案的安全价值评估进行了深入研究。首先,本文结合输电网规划问题的特点,设计了基于离散猴群算法的输电网优化规划全局寻优策略,以作为电网规划辅助决策工具中提出比选方案环节的核心算法。该算法由爬过程、望-跳过程、合作过程、翻过程以及随机扰动等步骤组成,其中大、小两种步长爬过程的设计解决了原猴群算法求解离散优化问题时爬过程失效的不足,而合作过程和随机扰动的引入也提高了算法的计算效率。算例结果表明离散猴群算法计算速度快,鲁棒性强,能够应用于较大规模输电网规划问题的求解。其次,本文提出了一种输电网优化规划的局部寻优策略。针对去掉当前规划方案中的一条支路后可能出现的元件过负荷、出现孤立节点(或孤立系统)和对系统无任何影响三种情况,分别定义了局部节点集、局部支路集和有效局部支路集,并由此定义了当前规划方案的邻域。通过变换,将局部搜索问题转化为0-1规划问题,采用隐枚举法进行求解。针对输电网规划问题特点所提出的剪枝策略能够有效减少枚举过程中需要评估的节点数量,进而提高搜索效率。该局部搜索策略一方面可以增强离散猴群算法的局部寻优能力,另一方面也可作为电网规划方案的调整工具,辅助规划人员对已有规划方案进行局部调整。在本文的最后,以大规模风电集中接入为背景,将电源规划与电网规划统筹考虑,建立了基于系统静态和动态安全性价值的电源、电网统一规划模型。在安全性价值的评估中,以日前机组组合为工具,以预测的规划水平年时序负荷和风电出力数据为基础,通过全年逐时段的仿真,评估对可能发生的预想事故进行预防控制和紧急控制所带来的发电燃料成本、环境成本以及切机、切负荷成本,同时计入负荷和风电出力不确定性引起控制措施无效时的社会损失,从而为规划方案的安全性评估提供了一个系统化方法,也将电力系统规划的视角从传统的技术经济评估拓宽为社会价值的评估。预防控制与紧急控制中对连锁事故的考虑为规划方案安全性评估中嵌入连锁事故的影响提供了有力的工具,也使得系统安全性的评估更为全面、合理。更多还原

【Abstract】 The traditional power system planning faces new challenges due to the integration of large-scale renewable energy and the construction of ultra high voltage power grids. The development and evaluation of planning schemes should not just rely on the planners’experience, whereas the efficient and systematic approaches must be adopted to assist planners to make decisions. With a view to the several major power blackouts in the world in recent years, how to systematically assess the security of power system planning schemes becomes an urgent problem. Therefore, this dissertation designs an optimization strategy for transmission network expansion planning from two aspects of global and local, and studies the evaluation of the value of security of power system planning schemes thoroughly.Firstly, in view of the features of transmission expansion planning (TEP), discrete monkey algorithm (DMA) is proposed as the global optimization strategy for solving the TEP problem, which can be used as the core algorithm in the decision support tools for planners. It includes climb process, watch-jump process, cooperation process, somersault process and termination criteria. Large-step and small-step climb processes are designed to avoid invalid climb process when solving optimization problems with discrete variables by primary monkey algorithm. Cooperation process and stochastic perturbation mechanism are also introduced to improve the computational efficiency. Numerical results demonstrate that DMA has strong robustness and is capable of solving large-scale TEP problems rapidly.Secondly, a local search strategy is proposed for the TEP problem. Removing one circuit in the current transmission planning scheme may make some components overloaded, some buses isolated or the remained system intact. Based on the three situations, three sets known as local bus, local circuit and effective local circuit are defined, and thus the neighborhood of current transmission planning scheme is presented. Then, the local search (LS) in the neighborhood is transformed into a 0-1 programming problem by variable transformation and the zero-one implicit enumeration method is employed to solve the problem, in which pruning strategies concerning the characteristics of TEP are designed to reduce the number of nodes to be assessed in enumeration process and improve search efficiency. The local search strategy, on the one hand can significantly improve the local search capability in global optimization algorithm, and on the other hand can help the planners adjust the planning schemes.Finally, concerning the integration of large-scale wind power, the integrated model of generation and transmission expansion is proposed based on the assessment of the value of static and dynamic security. Based on the predicted hourly load and wind power output data in the planning horizon, the unit commitment is used to evaluate the costs of preventive control, emergency control and social loss due to the uncertainty of load and wind power. The cost of preventive control consists of power generation fuel cost, the environmental cost and the load shedding cost. This not only provides a systematic method of secutity assessment of power system expansion plans, but also broadens the perspective of power system planning from the technology and economic assessment to the measure of the value of the whole society. In the assessment process, the preventive control and emergency control of cascading failures are also presented, which provides a powerful tool for cascading failure analysis of planning schemes and makes the security assessment more comprehensive and reasonable.更多还原