To reveal the energy transmission through a hybrid phononic crystal structure, power flow analysis is carried out in this paper. Hysteretic damping having significant relationship with power flow is added and correspo...To reveal the energy transmission through a hybrid phononic crystal structure, power flow analysis is carried out in this paper. Hysteretic damping having significant relationship with power flow is added and corresponding theoretical formulas of the dispersion relation are derived. Besides, the power flow in the hybrid structure is calculated by using the finite element method. The results show that as the damping increases, the boundaries of the band gaps become smoother and dimmer, i.e., broader width. With the increase of damping, the power flow is lowered at the resonance frequencies, while slightly increases near the resonance frequencies. The power flow maps manifest energy distribution in the hybrid structure within and out of the band gaps, which can be exploited in the optimization of the structure design.展开更多
混合型潮流控制器(hybrid power flow controller,HPFC)可以有效解决风电并网系统中存在的支路潮流过载问题,且相较于统一潮流控制器成本更低。针对现有的HPFC潮流优化研究尚未计及支路潮流最大值约束和风电不确定性的问题,提出一种基...混合型潮流控制器(hybrid power flow controller,HPFC)可以有效解决风电并网系统中存在的支路潮流过载问题,且相较于统一潮流控制器成本更低。针对现有的HPFC潮流优化研究尚未计及支路潮流最大值约束和风电不确定性的问题,提出一种基于场景削减的含HPFC风电并网系统最优潮流模型。首先,建立HPFC的功率注入模型,并推导了注入功率表达式;其次,采用K均值算法削减风电、负荷概率场景,通过CH(+)指标选择最优场景集合;最后,建立兼顾发电机运行成本、系统网络损耗、正常运行及N-1故障下的支路负载率的多目标优化模型,采用多目标粒子群优化(multi-objective particle swarm optimization,MOPSO)算法进行求解,利用模糊满意度函数在Pareto解集中筛选出折衷解。在MATLAB中仿真验证所提方法的有效性,结果表明该方法可以计及风电不确定性,保证电网在不同场景下的安全经济运行。展开更多
随着电力系统中多类型直流线路占比的逐步提升,调度系统与异构平台间的潮流数据交换需求明显增大,亟需研究新形态下交直流混联系统的潮流计算数据生成问题。该文从拓扑转换、网络拓扑分析、设备建模以及数据生成策略4个主要步骤,实现含...随着电力系统中多类型直流线路占比的逐步提升,调度系统与异构平台间的潮流数据交换需求明显增大,亟需研究新形态下交直流混联系统的潮流计算数据生成问题。该文从拓扑转换、网络拓扑分析、设备建模以及数据生成策略4个主要步骤,实现含交直流系统的基于可扩展标记语言的通用信息模型(common information model/extensible markup language,CIM/XML)数据到潮流计算输入数据的转换。首先,该文从设备间开关拓扑的角度,进行深度优先算法(depth first search,DFS)搜索和设备拓扑拼接,实现开关/节点模型到母线/支路模型的转换;其次,在筛选出活拓扑岛、剔除不带电设备后,着重分析了CIM/XML中换流器建模对交直流节点选取的影响,进而提出了直流节点选取规则和具备普适性的直流数据生成策略。最后,以某地调度500kV及以上交直流网络导出的CIM/XML数据为算例,潮流计算结果与数据采集与监视控制系统(supervisory control and data acquisition,SCADA)量测数据比对验证所提策略的有效性。展开更多
Progress has been developed in harvesting lowfrequency and irregular blue energy using a triboelectric–electromagnetic hybrid generator in recent years. However,the design of the high-efficiency, mechanically durable...Progress has been developed in harvesting lowfrequency and irregular blue energy using a triboelectric–electromagnetic hybrid generator in recent years. However,the design of the high-efficiency, mechanically durable hybrid structure is still challenging. In this study, we report a fully packaged triboelectric–electromagnetic hybrid generator(TEHG), in which magnets were utilized as the trigger to drive contact–separation-mode triboelectric nanogenerators(CS-TENGs) and coupled with copper coils to operate rotary freestanding-mode electromagnetic generators(RF-EMGs). The magnet pairs that produce attraction were used to transfer the external mechanical energy to the CS-TENGs, and packaging of the CS-TENGpart was achieved to protect it from the ambient environment. Under a rotatory speed of 100 rpm, the CS-TENGs enabled the TEHG to deliver an output voltage, current,and average power of 315.8 V, 44.6 μA, and ~ 90.7 μW,and the output of the RF-EMGs was 0.59 V, 1.78 m A, and 79.6 μW, respectively. The cylinder-like structure made the TEHG more easily driven by water flow and demonstrated to work as a practical power source to charge commercial capacitors. It can charge a 33μF capacitor from 0 to 2.1 V in 84 s, and the stored energy in the capacitor can drive an electronic thermometer and form a self-powered water-temperature sensing system.展开更多
为适应配电网多线路的潮流调节需求,进一步提高潮流调控能力和响应速度,文中提出一种新型配电网多线路混合式统一潮流控制器(multi-line hybrid unified power flow controller for distribution network, D-MHUPFC)。D-MHUPFC由Sen变...为适应配电网多线路的潮流调节需求,进一步提高潮流调控能力和响应速度,文中提出一种新型配电网多线路混合式统一潮流控制器(multi-line hybrid unified power flow controller for distribution network, D-MHUPFC)。D-MHUPFC由Sen变压器、统一潮流控制器(unified power flow controller, UPFC)和混合式有载分接开关组成,能够快速调节配电网多线路潮流。相较于传统调节方式,D-MHUPFC具有结构紧凑、响应快速、经济性好和可靠性高等优点。文中结合ZIP负荷模型,推导计及D-MHUPFC的多线路潮流方程,优化其协同控制策略,并搭建10 kV配电网仿真平台验证其可行性。结果显示,D-MHUPFC及其控制策略能在0.15 s内快速调节多线路潮流,转移过载功率,提高断面输电极限。D-MHUPFC能够解耦控制有功功率和无功功率,补偿误差小于1%,具有和UPFC相当的潮流调节能力。展开更多
柔性交流输电系统(flexible alternative current transmission systems,FACTS)装置如混合式统一潮流控制器(hybrid unified power flow controller,HUPFC)可调节线路潮流,有效提升输电网络的传输容量。为解决传统HUPFC中使用机械式有...柔性交流输电系统(flexible alternative current transmission systems,FACTS)装置如混合式统一潮流控制器(hybrid unified power flow controller,HUPFC)可调节线路潮流,有效提升输电网络的传输容量。为解决传统HUPFC中使用机械式有载分接开关调压带来的诸多问题,文中提出基于全电力电子有载分接开关的快速电磁式HUPFC。首先,针对其工作特性进行研究,并提出抑制开关切换过程中产生过压的方法。然后,根据不对称级电压Sen变压器的工作点合成方式存在自由度,实现一种开关切换次数最少的抽头选择策略,并给出从潮流指令改变到开关切换调压的详细步骤。最后,在Simulink中搭建220 kV双回线路仿真模型,对比快速电磁式HUPFC与传统HUPFC的潮流调节过程及结果。结果表明,全电力电子开关在响应速度和降低调节过程中的功率波动等方面更具优势,验证了快速电磁式HUPFC的可行性。展开更多
随着新能源发电技术与直流输电技术在大电网中的广泛应用,需要提出含新能源的交直流混联电网静态电压稳定分析方法。为此,该文针对含常规直流输电和多端柔性直流输电的交直流混联电网,采用区间数描述新能源电站出力的不确定波动,建立了...随着新能源发电技术与直流输电技术在大电网中的广泛应用,需要提出含新能源的交直流混联电网静态电压稳定分析方法。为此,该文针对含常规直流输电和多端柔性直流输电的交直流混联电网,采用区间数描述新能源电站出力的不确定波动,建立了交直流混联电网静态电压稳定裕度(static voltage stability margin,SVSM)区间计算的2个双层最优潮流模型,即计算SVSM区间上界的min-min模型和计算SVSM区间下界的max-min模型。计算区间SVSM上界的min-min双层优化模型可直接合并为单层优化模型求解。计算SVSM区间下界的max-min模型需要先通过二阶锥松弛和凸包络松弛等方法将内层模型转化为凸规划模型,并通过对偶优化理论得到内层凸规划模型的对偶规划模型,进而转化为单层优化模型求解。通过对修改后的IEEE-39节点系统和南方电网2个交直流混联电网算例的计算分析,并与蒙特卡洛抽样法和拉丁超立方抽样法的计算结果比较,验证了所提出方法的正确性与高效性。展开更多
文摘To reveal the energy transmission through a hybrid phononic crystal structure, power flow analysis is carried out in this paper. Hysteretic damping having significant relationship with power flow is added and corresponding theoretical formulas of the dispersion relation are derived. Besides, the power flow in the hybrid structure is calculated by using the finite element method. The results show that as the damping increases, the boundaries of the band gaps become smoother and dimmer, i.e., broader width. With the increase of damping, the power flow is lowered at the resonance frequencies, while slightly increases near the resonance frequencies. The power flow maps manifest energy distribution in the hybrid structure within and out of the band gaps, which can be exploited in the optimization of the structure design.
文摘随着电力系统中多类型直流线路占比的逐步提升,调度系统与异构平台间的潮流数据交换需求明显增大,亟需研究新形态下交直流混联系统的潮流计算数据生成问题。该文从拓扑转换、网络拓扑分析、设备建模以及数据生成策略4个主要步骤,实现含交直流系统的基于可扩展标记语言的通用信息模型(common information model/extensible markup language,CIM/XML)数据到潮流计算输入数据的转换。首先,该文从设备间开关拓扑的角度,进行深度优先算法(depth first search,DFS)搜索和设备拓扑拼接,实现开关/节点模型到母线/支路模型的转换;其次,在筛选出活拓扑岛、剔除不带电设备后,着重分析了CIM/XML中换流器建模对交直流节点选取的影响,进而提出了直流节点选取规则和具备普适性的直流数据生成策略。最后,以某地调度500kV及以上交直流网络导出的CIM/XML数据为算例,潮流计算结果与数据采集与监视控制系统(supervisory control and data acquisition,SCADA)量测数据比对验证所提策略的有效性。
基金funded by Natural Science Foundation of China (NSFC) (Grant No. U1432249)the National Key R&D Program of China (Grant 2017YFA0205002)+5 种基金the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)supported by Collaborative Innovation Center of Suzhou Nano Science & Technologythe support from China Postdoctoral Science Foundation (2017M610346)Natural Science Foundation of Jiangsu Province of China (BK20170343)Nantong Municipal Science and Technology Programthe support from Jiangsu University National Science Research Program (16KJB110021)
文摘Progress has been developed in harvesting lowfrequency and irregular blue energy using a triboelectric–electromagnetic hybrid generator in recent years. However,the design of the high-efficiency, mechanically durable hybrid structure is still challenging. In this study, we report a fully packaged triboelectric–electromagnetic hybrid generator(TEHG), in which magnets were utilized as the trigger to drive contact–separation-mode triboelectric nanogenerators(CS-TENGs) and coupled with copper coils to operate rotary freestanding-mode electromagnetic generators(RF-EMGs). The magnet pairs that produce attraction were used to transfer the external mechanical energy to the CS-TENGs, and packaging of the CS-TENGpart was achieved to protect it from the ambient environment. Under a rotatory speed of 100 rpm, the CS-TENGs enabled the TEHG to deliver an output voltage, current,and average power of 315.8 V, 44.6 μA, and ~ 90.7 μW,and the output of the RF-EMGs was 0.59 V, 1.78 m A, and 79.6 μW, respectively. The cylinder-like structure made the TEHG more easily driven by water flow and demonstrated to work as a practical power source to charge commercial capacitors. It can charge a 33μF capacitor from 0 to 2.1 V in 84 s, and the stored energy in the capacitor can drive an electronic thermometer and form a self-powered water-temperature sensing system.
文摘为适应配电网多线路的潮流调节需求,进一步提高潮流调控能力和响应速度,文中提出一种新型配电网多线路混合式统一潮流控制器(multi-line hybrid unified power flow controller for distribution network, D-MHUPFC)。D-MHUPFC由Sen变压器、统一潮流控制器(unified power flow controller, UPFC)和混合式有载分接开关组成,能够快速调节配电网多线路潮流。相较于传统调节方式,D-MHUPFC具有结构紧凑、响应快速、经济性好和可靠性高等优点。文中结合ZIP负荷模型,推导计及D-MHUPFC的多线路潮流方程,优化其协同控制策略,并搭建10 kV配电网仿真平台验证其可行性。结果显示,D-MHUPFC及其控制策略能在0.15 s内快速调节多线路潮流,转移过载功率,提高断面输电极限。D-MHUPFC能够解耦控制有功功率和无功功率,补偿误差小于1%,具有和UPFC相当的潮流调节能力。
文摘柔性交流输电系统(flexible alternative current transmission systems,FACTS)装置如混合式统一潮流控制器(hybrid unified power flow controller,HUPFC)可调节线路潮流,有效提升输电网络的传输容量。为解决传统HUPFC中使用机械式有载分接开关调压带来的诸多问题,文中提出基于全电力电子有载分接开关的快速电磁式HUPFC。首先,针对其工作特性进行研究,并提出抑制开关切换过程中产生过压的方法。然后,根据不对称级电压Sen变压器的工作点合成方式存在自由度,实现一种开关切换次数最少的抽头选择策略,并给出从潮流指令改变到开关切换调压的详细步骤。最后,在Simulink中搭建220 kV双回线路仿真模型,对比快速电磁式HUPFC与传统HUPFC的潮流调节过程及结果。结果表明,全电力电子开关在响应速度和降低调节过程中的功率波动等方面更具优势,验证了快速电磁式HUPFC的可行性。
文摘随着新能源发电技术与直流输电技术在大电网中的广泛应用,需要提出含新能源的交直流混联电网静态电压稳定分析方法。为此,该文针对含常规直流输电和多端柔性直流输电的交直流混联电网,采用区间数描述新能源电站出力的不确定波动,建立了交直流混联电网静态电压稳定裕度(static voltage stability margin,SVSM)区间计算的2个双层最优潮流模型,即计算SVSM区间上界的min-min模型和计算SVSM区间下界的max-min模型。计算区间SVSM上界的min-min双层优化模型可直接合并为单层优化模型求解。计算SVSM区间下界的max-min模型需要先通过二阶锥松弛和凸包络松弛等方法将内层模型转化为凸规划模型,并通过对偶优化理论得到内层凸规划模型的对偶规划模型,进而转化为单层优化模型求解。通过对修改后的IEEE-39节点系统和南方电网2个交直流混联电网算例的计算分析,并与蒙特卡洛抽样法和拉丁超立方抽样法的计算结果比较,验证了所提出方法的正确性与高效性。