Traditional seawater desalination requires high amounts of energy, with correspondingly high costs and limited benefits, hindering wider applications of the process. To further improve the comprehensive economic benef...Traditional seawater desalination requires high amounts of energy, with correspondingly high costs and limited benefits, hindering wider applications of the process. To further improve the comprehensive economic benefits of seawater desalination, the desalination load can be combined with renewable energy sources such as solar energy, wind energy, and ocean energy or with the power grid to ensure its effective regulation. Utilizing energy internet(EI) technology, energy balance demand of the regional power grid, and coordinated control between coastal multi-source multi-load and regional distribution network with desalination load is reviewed herein. Several key technologies, including coordinated control of coastal multi-source multi-load system with seawater desalination load, flexible interaction between seawater desalination and regional distribution network, and combined control of coastal multi-source multi-load storage system with seawater desalination load, are discussed in detail. Adoption of the flexible interaction between seawater desalination and regional distribution networks is beneficial for solving water resource problems, improving the ability to dissipate distributed renewable energy, balancing and increasing grid loads, improving the safety and economy of coastal power grids, and achieving coordinated and comprehensive application of power grids, renewable energy sources, and coastal loads.展开更多
This paper presents the problem of robust H∞?load frequency controller design and robust H￥ based approach called advanced frequency control (AFC). The objective is to split the task of balancing frequency ...This paper presents the problem of robust H∞?load frequency controller design and robust H￥ based approach called advanced frequency control (AFC). The objective is to split the task of balancing frequency deviations introduced by renewable energy source (RES) and load variations according to the capabilities of storage and generators. The problem we address is to design an output feedback controller such that, all admissible parameter uncertainties, the closed-loop system satisfies not only the prespecified H∞? norm constraint on the transfer function from the disturbance input to the system output. The conventional generators mainly balance the low-frequency components and load variations while the energy storage devices compensate the high- frequency components. In order to enable the controller design for storage devices located at buses with no generators, a model for the frequency at such a bus is developed. Then, AEC controllers are synthesized through decentralized static output feedback to reduce the complexity. The conditions for the existence of desired controllers are derived in terms of a linear matrix inequality (LMI) algorithm is improved. From the simulation results, the system responses with the proposed controller are the best transient responses.展开更多
Mobility is one of the major new paradigms of the current Internet, and this is driving most of the research activity in networking throughout the World. The Mobility of Wireless Sensor Networks (WSN) has become a hot...Mobility is one of the major new paradigms of the current Internet, and this is driving most of the research activity in networking throughout the World. The Mobility of Wireless Sensor Networks (WSN) has become a hot research theme in recent years due to its wide range of applications ranging from medical research to military. The widely adopted standard for wireless sensor network platform is IEEE 802.15.4/ZigBee. The IEEE 802.15.4/ZigBee is considered the “technology of choice” due to low-power, cost-effective communication and the reliability they provide. In this paper, we perform extensive network evaluation, to study the Effect of coordinator mobility on ZigBee mesh network, using OPNET Modeler. In mobile coordinator, the type of the trajectory along with the node density and the traffic are the major factors that decide the system performance. The results obtained from the wide analysis of ZigBee mesh network shows variation when the routers are placed at Hexagonal configuration with a mobile coordinator. In this paper, variations in load metric is analyzed in hexagonal configuration by enabling and disabling ACK. Thus the status of ACK also plays a critical role in analysing load metrics.展开更多
To improve the effect of the drug pricing reform,a business model of pharmaceutical e-commerce is introduced into the pharmaceutical supply chain.First,based on the measures of the drug pricing reform,a dual-channel m...To improve the effect of the drug pricing reform,a business model of pharmaceutical e-commerce is introduced into the pharmaceutical supply chain.First,based on the measures of the drug pricing reform,a dual-channel model is established,consisting of a drugstore and a hospital.The analysis of the model indicates that the reform leads to higher costs for patients.Then,an e-pharmacy is added to the dual-channel supply chain.Meanwhile,to reduce the home-delivery cost of the e-pharmacy,a multi-channel coordination strategy called“order online,delivery by drugstore”is proposed.By comparing the optimal values under the two models with and without coordination strategy,respectively,the results show that the profits of the e-pharmacy and the drugstore increase while the retail prices of drugs drop,and a large number of patients are diverted from the hospital.Therefore,the business model of pharmaceutical e-commerce with multi-channel coordination can greatly improve the effect of the drug pricing reform.展开更多
As the existing coordinated control strategies between grid and unit have limitations in isolated power system, this paper introduces new coordinated control strategies which can improve the stability of isolated syst...As the existing coordinated control strategies between grid and unit have limitations in isolated power system, this paper introduces new coordinated control strategies which can improve the stability of isolated system operation. This paper analyzes the power grid side and unit side influence factors on the isolated power system. The dynamic models which are suitable for islanding operation are applied to simulate and analyze the stability and dynamic characteristics of the isolated power system under the conditions of different load disturbances and governor parameters. With considering the differences of frequency characteristics between the interconnected and isolated power system, the adjusting and optimization methods of under frequency load shedding are proposed to meet the frequency stability requirements simultaneously in the two cases. Not only proper control strategies of the power plant but the settings of their parameters are suggested to improve the operation stability of the isolated power system. To confirm the correctness and effectiveness of the method mentioned above, the isolated system operation test was conducted under the real power system condition, and the results show that the proposed coordinated control strategies can greatly improve stability of the isolated power system.展开更多
In this study,a novel unloading method was developed for the operation of the unloading spout during the loading process in a master-slave automatic harvesting system.It demonstrated that uniform and full loading in t...In this study,a novel unloading method was developed for the operation of the unloading spout during the loading process in a master-slave automatic harvesting system.It demonstrated that uniform and full loading in the grain tank can be achieved by uninterrupted unloading with the motion of the unloading spout.First,the overflow algorithm is proposed to divide the loading process into multiple loading rounds.In each round,a specific loading area and target loading height are assigned to achieve better uniformity.Subsequently,complete coverage path planning and transfer path planning algorithms are developed to guide the motion of the unloading spout during different loading rounds.With the motion of the unloading spout,loading can be carried out accurately to maximize the capacity utilization of the grain tank,which can reduce the round-trip frequency of the transport vehicle and improve the energy and time efficiency of the harvesting operation.Simulation results are provided to validate the excellent performance of the presented unloading method.展开更多
为充分挖掘源-荷侧可调度资源,优化综合能源系统(integrated energy system,IES)的经济性能和低碳效益,提出一种考虑源-荷协调响应的综合能源系统优化调度策略。在能源供给侧,利用余热设备和电-氢耦合系统,构建电、热能灵活转换与输出...为充分挖掘源-荷侧可调度资源,优化综合能源系统(integrated energy system,IES)的经济性能和低碳效益,提出一种考虑源-荷协调响应的综合能源系统优化调度策略。在能源供给侧,利用余热设备和电-氢耦合系统,构建电、热能灵活转换与输出的源侧响应模型;在负荷需求侧,综合考虑多元负荷的中断、时移等响应特性,并结合电动汽车充电站的运行约束,构建负荷侧响应模型;为评估综合能源系统负荷需求的综合满意程度,提出了一种负荷满意度综合评价指标,通过商业求解器对综合能源系统优化模型进行仿真求解。仿真结果表明,所提策略在保障用能质量的同时有效降低了系统运行成本。展开更多
为解决基于模块化多电平换流器的柔性直流输电系统(modular multilevel converter based high voltage direct current,MMC-HVDC)在陆上交流电网故障时出现的盈余功率问题,首先计算验证了能量预警值的合理性,并设计了自适应动作能量值,...为解决基于模块化多电平换流器的柔性直流输电系统(modular multilevel converter based high voltage direct current,MMC-HVDC)在陆上交流电网故障时出现的盈余功率问题,首先计算验证了能量预警值的合理性,并设计了自适应动作能量值,解决距离和控制转换时延造成子模块过电压的问题;然后分析网侧变流器(grid-side converter,GSC)在低压穿越期间的动态输出特性,提出了基于直流电压变化率反馈的海上换流站精准降压控制用以进行风机减载;最终通过整定协同控制的逻辑与控制参数,提出了一种基于风机精准减载与子模块电容能量协同控制的低电压故障穿越策略,解决故障期间系统能量裕度利用率低与耗能装置投资大的问题。在MATLAB/Simulink中搭建系统仿真模型验证方法有效性,并与现有方法比较。仿真结果表明,所提方法可显著减少甚至避免耗能装置的投入,且具有自适应性,可在不同故障工况下尽可能利用MMC-HVDC系统的能量裕度,尤其在故障程度较轻的工况下,能在故障消除时保留部分能量裕度,有效应对电压二次跌落,提高系统低压穿越能力。展开更多
5G基站、分布式光伏(distributed photovoltaic,DPV)等分布式资源大规模参与配电网经济与电能质量等多目标优化调度,致使配电网调控模型决策变量复杂、求解时间慢等问题凸显。为此,提出一种考虑5G基站调控潜力和多资源协同的配电网分层...5G基站、分布式光伏(distributed photovoltaic,DPV)等分布式资源大规模参与配电网经济与电能质量等多目标优化调度,致使配电网调控模型决策变量复杂、求解时间慢等问题凸显。为此,提出一种考虑5G基站调控潜力和多资源协同的配电网分层分区优化方法。首先,考虑5G基站通信流量波动特性,建立计及闲置荷电状态(state of charge,SOC)约束的5G基站调控潜力模型。基于此,再建立配电网分层分区优化模型。上层以配电网综合效益最优为目标进行集中式调度,从而确定配电网分组投切电容器组、静止无功发生器等自身资源的动作方案。下层为分区调度,结合电压-功率灵敏度和考虑5G基站通信负荷的源荷不匹配度指标进行配电网物理分区,建立面向5G基站闲置SOC和DPV剩余容量的配电网分区协调优化模型,并采用二阶锥规划和同步型交替方向乘子法相结合的混合算法进行求解。最后,以改进的IEEE33节点配电网为算例,分析验证了所提方法的有效性。结果表明,所提方法能够提高配电网调控模型的求解能力,并提升配电网经济性和电压质量。展开更多
To characterize the spatial patterns of vertical crustal movement of Chinese mainland,GNSS imaging technology was applied to map the tectonic deformation of the region.In this study,the vertical crustal velocities inf...To characterize the spatial patterns of vertical crustal movement of Chinese mainland,GNSS imaging technology was applied to map the tectonic deformation of the region.In this study,the vertical crustal velocities inferred from GNSS data for Chinese mainland over two decades were rigorously estimated.First,by analyzing the vertical displacement time series from continuous GNSS stations and environmental load data,we found that the annual and semi-annual vertical displacements are highly correlated.This indicates that the vertical seasonal variations on the ground surface are mainly caused by environmental loading.After removing the seasonal variations caused by environmental loads from the GNSS time series,we applied an improved PCA technique to filter out common mode errors.Next,we estimated the optimal noise models for the filtered time series and derived the vertical velocity field of Chinese mainland.Finally,we employed an empirical Spatial Structure Function(SSF)to image the tectonic deformation of Chinese mainland.This method effectively mitigates issues with abrupt circular arc-shaped boundaries in GNSS imaging caused by sparse station networks.The imaging results show that vertical crustal deformation in Chinese mainland generally ranges from-3 to 3 mm/yr,with significant spatial variability.The central and northern parts of Qinghai-Xizang Plateau are identified as primary subsidence zones,indicating that plate boundaries and tectonic compression continue to shape the crustal movement in these regions.The major uplift zones are located in northern and central China,likely linked to regional tectonic activity and plate compression.Subsidence deformation in parts of eastern China appears to be influenced by human activities.展开更多
基金supported by the State Grid Science and Technology Project, “Study on Multi-source and Multiload Coordination and Optimization Technology Considering Desalination of Sea Water” (No. SGTJDK00DWJS1800011)
文摘Traditional seawater desalination requires high amounts of energy, with correspondingly high costs and limited benefits, hindering wider applications of the process. To further improve the comprehensive economic benefits of seawater desalination, the desalination load can be combined with renewable energy sources such as solar energy, wind energy, and ocean energy or with the power grid to ensure its effective regulation. Utilizing energy internet(EI) technology, energy balance demand of the regional power grid, and coordinated control between coastal multi-source multi-load and regional distribution network with desalination load is reviewed herein. Several key technologies, including coordinated control of coastal multi-source multi-load system with seawater desalination load, flexible interaction between seawater desalination and regional distribution network, and combined control of coastal multi-source multi-load storage system with seawater desalination load, are discussed in detail. Adoption of the flexible interaction between seawater desalination and regional distribution networks is beneficial for solving water resource problems, improving the ability to dissipate distributed renewable energy, balancing and increasing grid loads, improving the safety and economy of coastal power grids, and achieving coordinated and comprehensive application of power grids, renewable energy sources, and coastal loads.
文摘This paper presents the problem of robust H∞?load frequency controller design and robust H￥ based approach called advanced frequency control (AFC). The objective is to split the task of balancing frequency deviations introduced by renewable energy source (RES) and load variations according to the capabilities of storage and generators. The problem we address is to design an output feedback controller such that, all admissible parameter uncertainties, the closed-loop system satisfies not only the prespecified H∞? norm constraint on the transfer function from the disturbance input to the system output. The conventional generators mainly balance the low-frequency components and load variations while the energy storage devices compensate the high- frequency components. In order to enable the controller design for storage devices located at buses with no generators, a model for the frequency at such a bus is developed. Then, AEC controllers are synthesized through decentralized static output feedback to reduce the complexity. The conditions for the existence of desired controllers are derived in terms of a linear matrix inequality (LMI) algorithm is improved. From the simulation results, the system responses with the proposed controller are the best transient responses.
文摘Mobility is one of the major new paradigms of the current Internet, and this is driving most of the research activity in networking throughout the World. The Mobility of Wireless Sensor Networks (WSN) has become a hot research theme in recent years due to its wide range of applications ranging from medical research to military. The widely adopted standard for wireless sensor network platform is IEEE 802.15.4/ZigBee. The IEEE 802.15.4/ZigBee is considered the “technology of choice” due to low-power, cost-effective communication and the reliability they provide. In this paper, we perform extensive network evaluation, to study the Effect of coordinator mobility on ZigBee mesh network, using OPNET Modeler. In mobile coordinator, the type of the trajectory along with the node density and the traffic are the major factors that decide the system performance. The results obtained from the wide analysis of ZigBee mesh network shows variation when the routers are placed at Hexagonal configuration with a mobile coordinator. In this paper, variations in load metric is analyzed in hexagonal configuration by enabling and disabling ACK. Thus the status of ACK also plays a critical role in analysing load metrics.
基金The National Natural Science Foundation of China(No.71390333)the Key R&D Plans of Jiangsu Province(No.BE2017156).
文摘To improve the effect of the drug pricing reform,a business model of pharmaceutical e-commerce is introduced into the pharmaceutical supply chain.First,based on the measures of the drug pricing reform,a dual-channel model is established,consisting of a drugstore and a hospital.The analysis of the model indicates that the reform leads to higher costs for patients.Then,an e-pharmacy is added to the dual-channel supply chain.Meanwhile,to reduce the home-delivery cost of the e-pharmacy,a multi-channel coordination strategy called“order online,delivery by drugstore”is proposed.By comparing the optimal values under the two models with and without coordination strategy,respectively,the results show that the profits of the e-pharmacy and the drugstore increase while the retail prices of drugs drop,and a large number of patients are diverted from the hospital.Therefore,the business model of pharmaceutical e-commerce with multi-channel coordination can greatly improve the effect of the drug pricing reform.
文摘As the existing coordinated control strategies between grid and unit have limitations in isolated power system, this paper introduces new coordinated control strategies which can improve the stability of isolated system operation. This paper analyzes the power grid side and unit side influence factors on the isolated power system. The dynamic models which are suitable for islanding operation are applied to simulate and analyze the stability and dynamic characteristics of the isolated power system under the conditions of different load disturbances and governor parameters. With considering the differences of frequency characteristics between the interconnected and isolated power system, the adjusting and optimization methods of under frequency load shedding are proposed to meet the frequency stability requirements simultaneously in the two cases. Not only proper control strategies of the power plant but the settings of their parameters are suggested to improve the operation stability of the isolated power system. To confirm the correctness and effectiveness of the method mentioned above, the isolated system operation test was conducted under the real power system condition, and the results show that the proposed coordinated control strategies can greatly improve stability of the isolated power system.
文摘In this study,a novel unloading method was developed for the operation of the unloading spout during the loading process in a master-slave automatic harvesting system.It demonstrated that uniform and full loading in the grain tank can be achieved by uninterrupted unloading with the motion of the unloading spout.First,the overflow algorithm is proposed to divide the loading process into multiple loading rounds.In each round,a specific loading area and target loading height are assigned to achieve better uniformity.Subsequently,complete coverage path planning and transfer path planning algorithms are developed to guide the motion of the unloading spout during different loading rounds.With the motion of the unloading spout,loading can be carried out accurately to maximize the capacity utilization of the grain tank,which can reduce the round-trip frequency of the transport vehicle and improve the energy and time efficiency of the harvesting operation.Simulation results are provided to validate the excellent performance of the presented unloading method.
文摘为充分挖掘源-荷侧可调度资源,优化综合能源系统(integrated energy system,IES)的经济性能和低碳效益,提出一种考虑源-荷协调响应的综合能源系统优化调度策略。在能源供给侧,利用余热设备和电-氢耦合系统,构建电、热能灵活转换与输出的源侧响应模型;在负荷需求侧,综合考虑多元负荷的中断、时移等响应特性,并结合电动汽车充电站的运行约束,构建负荷侧响应模型;为评估综合能源系统负荷需求的综合满意程度,提出了一种负荷满意度综合评价指标,通过商业求解器对综合能源系统优化模型进行仿真求解。仿真结果表明,所提策略在保障用能质量的同时有效降低了系统运行成本。
文摘为解决基于模块化多电平换流器的柔性直流输电系统(modular multilevel converter based high voltage direct current,MMC-HVDC)在陆上交流电网故障时出现的盈余功率问题,首先计算验证了能量预警值的合理性,并设计了自适应动作能量值,解决距离和控制转换时延造成子模块过电压的问题;然后分析网侧变流器(grid-side converter,GSC)在低压穿越期间的动态输出特性,提出了基于直流电压变化率反馈的海上换流站精准降压控制用以进行风机减载;最终通过整定协同控制的逻辑与控制参数,提出了一种基于风机精准减载与子模块电容能量协同控制的低电压故障穿越策略,解决故障期间系统能量裕度利用率低与耗能装置投资大的问题。在MATLAB/Simulink中搭建系统仿真模型验证方法有效性,并与现有方法比较。仿真结果表明,所提方法可显著减少甚至避免耗能装置的投入,且具有自适应性,可在不同故障工况下尽可能利用MMC-HVDC系统的能量裕度,尤其在故障程度较轻的工况下,能在故障消除时保留部分能量裕度,有效应对电压二次跌落,提高系统低压穿越能力。
文摘5G基站、分布式光伏(distributed photovoltaic,DPV)等分布式资源大规模参与配电网经济与电能质量等多目标优化调度,致使配电网调控模型决策变量复杂、求解时间慢等问题凸显。为此,提出一种考虑5G基站调控潜力和多资源协同的配电网分层分区优化方法。首先,考虑5G基站通信流量波动特性,建立计及闲置荷电状态(state of charge,SOC)约束的5G基站调控潜力模型。基于此,再建立配电网分层分区优化模型。上层以配电网综合效益最优为目标进行集中式调度,从而确定配电网分组投切电容器组、静止无功发生器等自身资源的动作方案。下层为分区调度,结合电压-功率灵敏度和考虑5G基站通信负荷的源荷不匹配度指标进行配电网物理分区,建立面向5G基站闲置SOC和DPV剩余容量的配电网分区协调优化模型,并采用二阶锥规划和同步型交替方向乘子法相结合的混合算法进行求解。最后,以改进的IEEE33节点配电网为算例,分析验证了所提方法的有效性。结果表明,所提方法能够提高配电网调控模型的求解能力,并提升配电网经济性和电压质量。
基金National Natural Science Foundation of China(42274012,42004001)the Science and Technology Innovation Project of Anhui Surveying and Mapping Bureau(2025-KJ-08)+1 种基金the Open Fund of Wuhan Gravitation and Solid Earth Tides,National Observation and Research Station(WHYWZ202107)the Fundamental Research Funds for the Central Universities(JZ2022HGTB0268)。
文摘To characterize the spatial patterns of vertical crustal movement of Chinese mainland,GNSS imaging technology was applied to map the tectonic deformation of the region.In this study,the vertical crustal velocities inferred from GNSS data for Chinese mainland over two decades were rigorously estimated.First,by analyzing the vertical displacement time series from continuous GNSS stations and environmental load data,we found that the annual and semi-annual vertical displacements are highly correlated.This indicates that the vertical seasonal variations on the ground surface are mainly caused by environmental loading.After removing the seasonal variations caused by environmental loads from the GNSS time series,we applied an improved PCA technique to filter out common mode errors.Next,we estimated the optimal noise models for the filtered time series and derived the vertical velocity field of Chinese mainland.Finally,we employed an empirical Spatial Structure Function(SSF)to image the tectonic deformation of Chinese mainland.This method effectively mitigates issues with abrupt circular arc-shaped boundaries in GNSS imaging caused by sparse station networks.The imaging results show that vertical crustal deformation in Chinese mainland generally ranges from-3 to 3 mm/yr,with significant spatial variability.The central and northern parts of Qinghai-Xizang Plateau are identified as primary subsidence zones,indicating that plate boundaries and tectonic compression continue to shape the crustal movement in these regions.The major uplift zones are located in northern and central China,likely linked to regional tectonic activity and plate compression.Subsidence deformation in parts of eastern China appears to be influenced by human activities.
