In this paper, after taking th e effect of axis force on bending into consideration, the general potential ener gy for the circular double articulated arch is established undergoing vertical d istributive load g 0/...In this paper, after taking th e effect of axis force on bending into consideration, the general potential ener gy for the circular double articulated arch is established undergoing vertical d istributive load g 0/ cos 2θ . With sufficient engineering precision, the fourth approximations to the destabilizing critical load of the arch under t his load are obtained by Ritz method. The approximations to the critical load ta ble are listed for various center angles of arch, and are contrasted with the cr itical load circular arch undergoing radial uniform load. Some reference results have been obtained.展开更多
Distribution networks in China and several other countries are predominantly neutral inefficiently grounding systems(NIGSs),and more than 80%of the faults in distribution networks are single-phase-to-ground(SPG)faults...Distribution networks in China and several other countries are predominantly neutral inefficiently grounding systems(NIGSs),and more than 80%of the faults in distribution networks are single-phase-to-ground(SPG)faults.Because of the weak fault current and imperfect monitoring equipment configurations,methods used to determine the faulty line secti ons with SPG faults in NIGSs are in effective.The developme nt and application of distributi on-level phasor measurement units(PMUs)provide further comprehensive fault information for fault diagnosis in a distribution network.When an SPG fault occurs,the transient energy of the faulted line section tends to be higher than the sum of the transient energies of other line sections.In this regard,transient energy-based fault location algorithms appear to be a promising resolution.In this study,a field test plan was designed and implemented for a 10 kV distribution network.The test results dem on strate the effective ness of the transient en ergy-based SPG locati on method in practical distributi on networks.展开更多
光热(concentrated solar power,CSP)电站是一种清洁、灵活的新型可再生能源设备,在综合能源系统(integrated energy system,IES)中引入CSP电站为推动能源向低碳转型提供了有效方式。然而,可再生能源的不确定性以及经济与环境的矛盾,给...光热(concentrated solar power,CSP)电站是一种清洁、灵活的新型可再生能源设备,在综合能源系统(integrated energy system,IES)中引入CSP电站为推动能源向低碳转型提供了有效方式。然而,可再生能源的不确定性以及经济与环境的矛盾,给系统的经济、低碳、灵活和稳定运行带来了挑战。为此,提出一种计及多能灵活性的多目标分布鲁棒优化(distributionally robust optimization,DRO)调度策略。首先,针对可再生能源的不确定性,采用拉丁超立方抽样法结合Kantorovich场景削减法生成风电、光伏和CSP电站收集热功率的离散典型场景。其次,分别从能源供给、需求和转换环节对系统中灵活性资源进行量化,建立多能灵活性供需平衡约束。然后,以经济性和碳排放最优作为目标函数,建立基于多离散场景的两阶段多目标DRO模型,并采用列与约束生成算法进行迭代求解。针对多目标优化问题,通过ε-约束法求解得到帕累托前沿,并根据客观赋权法(criteria importance though intercrieria correlation,CRITIC)与优劣解距离法(technique for order preference by similarity to ideal solution,TOPSIS)(CRITICTOPSIS)综合决策出最终运行方案。仿真结果表明,所提模型有效提升了IES运行的灵活性裕度,达到了经济与环境的合理权衡。展开更多
文摘In this paper, after taking th e effect of axis force on bending into consideration, the general potential ener gy for the circular double articulated arch is established undergoing vertical d istributive load g 0/ cos 2θ . With sufficient engineering precision, the fourth approximations to the destabilizing critical load of the arch under t his load are obtained by Ritz method. The approximations to the critical load ta ble are listed for various center angles of arch, and are contrasted with the cr itical load circular arch undergoing radial uniform load. Some reference results have been obtained.
基金National Key R&D Program of China(2017YFB0902800)Science and Technology Project of State Grid Corporation of China(52094017003D)supported this work.
文摘Distribution networks in China and several other countries are predominantly neutral inefficiently grounding systems(NIGSs),and more than 80%of the faults in distribution networks are single-phase-to-ground(SPG)faults.Because of the weak fault current and imperfect monitoring equipment configurations,methods used to determine the faulty line secti ons with SPG faults in NIGSs are in effective.The developme nt and application of distributi on-level phasor measurement units(PMUs)provide further comprehensive fault information for fault diagnosis in a distribution network.When an SPG fault occurs,the transient energy of the faulted line section tends to be higher than the sum of the transient energies of other line sections.In this regard,transient energy-based fault location algorithms appear to be a promising resolution.In this study,a field test plan was designed and implemented for a 10 kV distribution network.The test results dem on strate the effective ness of the transient en ergy-based SPG locati on method in practical distributi on networks.
文摘光热(concentrated solar power,CSP)电站是一种清洁、灵活的新型可再生能源设备,在综合能源系统(integrated energy system,IES)中引入CSP电站为推动能源向低碳转型提供了有效方式。然而,可再生能源的不确定性以及经济与环境的矛盾,给系统的经济、低碳、灵活和稳定运行带来了挑战。为此,提出一种计及多能灵活性的多目标分布鲁棒优化(distributionally robust optimization,DRO)调度策略。首先,针对可再生能源的不确定性,采用拉丁超立方抽样法结合Kantorovich场景削减法生成风电、光伏和CSP电站收集热功率的离散典型场景。其次,分别从能源供给、需求和转换环节对系统中灵活性资源进行量化,建立多能灵活性供需平衡约束。然后,以经济性和碳排放最优作为目标函数,建立基于多离散场景的两阶段多目标DRO模型,并采用列与约束生成算法进行迭代求解。针对多目标优化问题,通过ε-约束法求解得到帕累托前沿,并根据客观赋权法(criteria importance though intercrieria correlation,CRITIC)与优劣解距离法(technique for order preference by similarity to ideal solution,TOPSIS)(CRITICTOPSIS)综合决策出最终运行方案。仿真结果表明,所提模型有效提升了IES运行的灵活性裕度,达到了经济与环境的合理权衡。
