多直流馈入受端电力系统分区及互联优化方法

Optimization Method for Partition and Interconnection of Multi-infeed DC Receiving-end Power System

合理的系统分区是中国广东等多直流馈入受端电力系统应对短路电流超标、复杂故障和交直流交互影响导致大停电等问题的根本措施。已有研究集中在开断交流支路选择方面,而系统分区在开断交流支路时往往需配套加强区内网架以满足电气支撑约束。为此,提出了一种分区及互联优化方法,能够对分区断面、区间及区内互联方案进行同步协调优化,在满足潮流传输、直流运行支撑等需求下确定合理的拓扑结构和电气强度。首先,以最小化指定规模及以上停电事故发生概率为目标函数,考虑系统安全约束,构建了系统分区及互联问题对应的优化模型;然后,基于最小单元定义实现了网架方案的数学化表达,并以最小单元间的联结关系作为优化变量;最后,采用和声搜索算法和蒙特卡洛仿真法求解所发展的模型。通过在广东实际电力系统的应用验证了文中所提方法的可行性和有效性。

Proper system partition is a fundamental measure to deal with the large-scale blackouts caused by short-circuit current overshoot,complex failures and AC-DC interaction in a multi-infeed DC receiving-end power system like Guangdong of China.The existing research focuses on the selection of AC line break,but the system partition often needs to strengthen the grid structure in the area to meet the electrical support constraints.For this purpose,an optimization method for partition and interconnection is proposed to carry out synchronously coordinated optimization for the interconnection schemes across,within and among partitions.Based on this model,reasonable topology and electrical strength are determined to meet the needs of power flow transmission and DC operation support.Firstly,the objective function is defined as minimizing the probability of blackouts at specified scales and above,and an optimization model of system partition and interconnection is put forward considering system security constraints.Secondly,the mathematical expression of network structure is developed based on the definition of the minimum unit of the system,and the interconnection relationship among the minimum units is used as an optimization variable.Finally,the harmonic search algorithm and Monte Carlo simulation method are used to solve the developed model.The feasibility and effectiveness of the proposed method are verified in the application in Guangdong power system.