Sewage flow optimization algorithm for large-scale urban sewer networks based on network community division

By considering the flow control of urban sewer networks to minimize the electricity consumption of pumping stations, a decomposition-coordination strategy for energy savings based on network community division is developed in this paper. A mathematical model characterizing the steady-state flow of urban sewer networks is first constructed, consisting of a set of algebraic equations with the structure transportation capacities captured as constraints. Since the sewer networks have no apparent natural hierarchical structure in general, it is very difficult to identify the clustered groups. A fast network division approach through calculating the betweenness of each edge is successfully applied to identify the groups and a sewer network with arbitrary configuration could be then decomposed into subnetworks. By integrating the coupling constraints of the subnetworks, the original problem is separated into N optimization subproblems in accordance with the network decomposition. Each subproblem is solved locally and the solutions to the subproblems are coordinated to form an appropriate global solution. Finally, an application to a specified large-scale sewer network is also investigated to demonstrate the validity of the proposed algorithm.

Coordination of PSS and FACTS Damping Controllers to Improve Small Signal Stability of Large-scale Power Systems

This paper presents an approach for designing parameters of power system stabilizer(PSS)and FACTS damping controllers in a large scale practical power system.The objective is maximizing damping ratio of the target mode,and tracking technology(MTT)is used to avoid frequent alternations of target mode in optimization procedures.An improved planted growth simulation algorithm(IPGSA),which has high search efficiency and quick convergence speed,is proposed to optimize controller parameters coordinately.Based on case study of a large-scale power grid,and by using local and interregional low-frequency oscillation modes as target modes,simulation results verify proposed method in this paper.Furthermore,coordination optimization strategy adapted to multi-operating conditions demonstrates that the proposed approach is robust.

考虑水流演进规律的引大济湟工程水量调度研究

针对引大济湟工程供水调度范围广、水利设施多样以及工程调度目标复杂等难点,提出考虑水流演进过程的大系统分解协调技术,构建引大济湟工程水量调度模型。该模型基于大系统协调分解理论将引大济湟工程划分为多个子系统,利用子系统间的水力联系构建协同机制,获取各项水利设施调度方案信息,并结合一维水动力模型获取各个节点断面的水位、流量关键信息。结果表明:相比于仅通过水量分配模型获取的调度方案,采用该模型得到的方案不仅可满足供水需求,还可实现对供水过程的动态跟踪、模拟仿真,为用户提供更为精准、科学的供水调度方案编制手段,进一步确保沿线供水安全。

水资源开发利用与区域经济发展协调管理递阶优化模型及算法研究

本文从大系统递阶优化控制理论出发,提出了水资源开发利用与区域经济发展协调管理的多级递阶优化模型,并针对该模型提出了一种新的算法。文中所研究的水资源系统是地面—地下水资源系统。在地面水系统中,给出了多目标开发利用管理模型;在地下水系统中,提出了地下水资源开发利用经济管理模型。然后设置一个协调模型来协调地面—地下水资源系统,使整个水资源系统处于优化运行状态。区域经济涉及区域内的各种工农业和城镇生活用水部门——用水系统。对该用水系统提出了分解—协调优化管理模型。最后在最高级设置总协调模型来协调供水与用水,使整个水资源系统与区域经济系统处于最佳的运行状态。

经济结构转型的碳减排效应

【目的】在技术创新减排效应边际递减背景下,挖掘经济结构转型的碳减排潜力对实现双碳目标具有重要意义。【方法】本文基于投入产出理论和结构分解分析,构建了一个描述经济转型驱动碳减排的解释性框架,运用中国2007—2017年的多区域投入产出表以及相应的碳排放数据,分别从产业和空间维度,系统分析能源结构、投入结构、中间生产结构、消费结构、投资结构与出口结构动态调整对碳减排的贡献,并按全国、区域和地区3个层次分别展开讨论。【结果】①观察期内由于结构变动带来的碳减排量约为1726.82百万t,中国经济实现了从技术降碳到结构减排的动力转换;②中间生产结构优化是结构性减排的支柱力量,且经济部门间产业结构优化效应远大于地区间资源要素再配置带来的空间结构优化效应;③区域内产业结构优化的碳减排效应更为显著,地理区位存在先天劣势的内陆地区并未能实现区域协同联动下的碳减排;④地区发展水平与经济结构转型的碳减排效应间主要表现出“尾部效应”和“规模效应”特征。【结论】经济结构转型是实现碳减排的关键路径,生产侧和需求侧结构优化形成的“双轮驱动”效应有助于持续推动中国低碳转型发展。