虚拟电厂(virtual powerplant,VPP)需要在快速变化的运行环境下协同大量分布式能源(distributed energy resources,DERs)满足上级电网的调节需求。当前有关VPP优化运行的研究需在每一个控制时段消耗较多的运算与通讯时间,不易应对快速...虚拟电厂(virtual powerplant,VPP)需要在快速变化的运行环境下协同大量分布式能源(distributed energy resources,DERs)满足上级电网的调节需求。当前有关VPP优化运行的研究需在每一个控制时段消耗较多的运算与通讯时间,不易应对快速变化的运行环境。自趋优(self-approaching optimization,SAO)为VPP运行提供了全新的理念,主张在变化的环境中,以细粒度的时间间隔快速更新DERs,确保VPP不断趋近于最优的运行状态。为实现这一理念,该文提出基于在线分布式优化(online distributed optimization,ODO)的VPPSAO运行方法。首先,建立含非储能型DERs和储能型DERs的VPP运行统一模型;其次,通过模型松弛变换等技术依次解决时间耦合、空间耦合、变量快速更新、激励机制与自主响应等问题,形成基于ODO的自趋算法;进而,定义趋优间隙以量化算法可能产生的最优性损失,并从理论上证明提出的算法具有严格的趋优间隙上确界。以分布式光伏、储能及电动汽车等DERs为例构造测试VPP,与其他不同方法进行算例对比,验证SAO运行方法在约束满足、优化性能、计算效率等方面的优势。展开更多
高比例新能源、电动汽车、储能电站等并网,迫切需要改进电网安全稳定控制技术体系,将海量分散可控资源纳入电网紧急控制范畴。针对紧急控制在线决策需求,该文给出以虚拟电厂(virtual power plant,VPP)为管控形式的分布式能源(distribute...高比例新能源、电动汽车、储能电站等并网,迫切需要改进电网安全稳定控制技术体系,将海量分散可控资源纳入电网紧急控制范畴。针对紧急控制在线决策需求,该文给出以虚拟电厂(virtual power plant,VPP)为管控形式的分布式能源(distributed energy resources,DERs)紧急功率调节能力量化描述和在线评估方法。首先,分析紧急功率调节能力的内涵及表述要求,给出调节能力的量化描述方法;其次,构建反映物理特性及考虑用户行为约束的VPP紧急功率调节能力评估综合模型;最后,给出考虑状态转移及边界约束的紧急功率多时间尺度调节能力计算方法,设计相关仿真计算模块,并实现与PSS/E接口。以含300台电动汽车及1000台空调的VPP为例,仿真验证所述方法的有效性。展开更多
We aim to systematically review challenges imposed by emerging distributed energy resources(DERs)to model in two basic distribution management system(DMS)online applications—power flow and short-circuit analysis,as w...We aim to systematically review challenges imposed by emerging distributed energy resources(DERs)to model in two basic distribution management system(DMS)online applications—power flow and short-circuit analysis,as well as to offer a systematic review of potential solutions.In the last decade,electronically coupled DERs became increasingly popular.DERs can employ a wide range of control strategies for power,current,or voltage control,in both normal and faulted conditions.Therefore,DERs cannot be modeled with the traditional PQ(load or generator bus)or PV(generator bus)bus types used for modeling synchronous and induction machines in online power flow calculations.Moreover,since fault currents of DERs are limited to predefined maximal values,electronically coupled DERs cannot be represented with traditional voltage source behind impedance models for online short-circuit calculation(SCC).However,most of the DMS software packages still use the traditional models to represent all DER types,including those that are electronically coupled.This paper shows that there will be large calculation errors in such practice,which make the system model an inadequate representation of the system.This will lead to serious errors in the management,control,and operation of distribution systems.Nonetheless,potential solutions to the challenges are systematically reviewed.Finally,the calculation results on a distribution test system with all DER types are used to prove the claim.展开更多
分布式电源、电动汽车、温控负荷等需求侧可控异构分散资源渗透率逐步增加,迫切需要对其有效整合后参与电网调控。虚拟电厂(virtualpowerplant,VPP)是聚合和管控海量分布式能源(distributed energy resources,DERs)的有效形式,而运行仿...分布式电源、电动汽车、温控负荷等需求侧可控异构分散资源渗透率逐步增加,迫切需要对其有效整合后参与电网调控。虚拟电厂(virtualpowerplant,VPP)是聚合和管控海量分布式能源(distributed energy resources,DERs)的有效形式,而运行仿真工具是发挥其作用的重要支撑。鉴于此,该文给出覆盖DER设备建模、异构DERs聚合和集群协同控制等全环节的VPP短时长精细化生产模拟方法,并设计面向VPP参与电网互动的开放式仿真系统。在分析VPP短时长精细化生产模拟需求的基础上,归纳精细化仿真关键技术;基于DERs物理特性分析及管控架构构建,提出包含设备层和管控层的VPP精细化建模方法;以通用开放为原则,设计仿真系统实现方案,通过模块化建模和通用化架构及互动接口设计,实现对多种电网仿真引擎和多类DERs模型兼容。以包含异构DERs的单个VPP为例,介绍典型日VPP生产模拟结果,并以包含多VPP的区域电网为例,给出DERs集群功率调节响应过程及其参与频率紧急控制和功角稳定紧急控制的效果,仿真结果验证了所述方法和系统的有效性。展开更多
An exponential-function-based droop control strategy for the distributed energy resources(DERs)is proposed to reduce the reactive power-sharing deviation,limit the minimum value of frequency/voltage,whilst improving t...An exponential-function-based droop control strategy for the distributed energy resources(DERs)is proposed to reduce the reactive power-sharing deviation,limit the minimum value of frequency/voltage,whilst improving the utilization rate of renewable energy.Both DERs and loads are interconnected to achieve a power exchange by converters,where the power management system should accurately share the active/reactive power demand.However,the proportional reactive power sharing often deteriorates due to its dependence on the line impedances.Thus,an exponential-function-based droop control is proposed to(1)prevent voltage and frequency from falling to the lower restraint,(2)achieve accurate reactive power sharing,(3)eliminate communication and improve the usage ratio of renewable energy.Furthermore,its stability is analyzed,and the application in islanded AC/DC hybrid microgrids is investigated to achieve the bidirectional power flow.The simulation and experimental results show that the reactive power sharing deviation can be reduced,and the utilization rate of renewable energy is improved by using the proposed method.Moreover,the simulation results illustrate that the system can maintain stable operation when the microgrid is switched from one supplied energy operation condition to another absorbed one.展开更多
The high penetration of distributed energy resources (DERs) will significantly challenge the power system operation and control due to their stochastic, intermittent, and fluctuation characteristics. This enhances the...The high penetration of distributed energy resources (DERs) will significantly challenge the power system operation and control due to their stochastic, intermittent, and fluctuation characteristics. This enhances the difficulty of congestion management of power systems in cross-border electricity market among different regions. For handling this, the Real-Time Market is proposed for balancing capacity trading against congestions. Several strategies for Real-Time Market dealing with congestions are proposed. The strategy of two-stage crossborder markets in Day-ahead, Intra-day and Real Time Market are introduced with the congestion constraints complied. Pre-Contingency strategy is proposed as the advance preparation for the future congestion, and In-Day redispatch is used for regulation. Accordingly, the requirements on facilities considering telemetry and remote control in a fast manner are discussed at last.展开更多
An economic evaluation of a network of distributed energy resources （DERs） comprising a microgrid structure of power delivery system in an Indian scenario has been made. The mathematical analysis is based on the app...An economic evaluation of a network of distributed energy resources （DERs） comprising a microgrid structure of power delivery system in an Indian scenario has been made. The mathematical analysis is based on the application of tuned genetic algorithm （TGA）. The analyses for optimal power operation pertaining to minimum cost have been made for two cases in Indian power delivery system. The first case deals with the consumers＇ individual optimal operation of DERs, while in the second one, consumers altogether form a microgrid with the optimal supply of power from DERs. The total annual costs for these two cases are found to be economically competitive and encouraging. A reduction of approximately 5.7% in the annual cost has been obtained in the case of microgid system than that in the separately operating consumers＇ system for a small locality of India. It is observed that the application of TGA results in a reduction of the minimum cost depicting an improved outcome in terms of energy economy.展开更多
文摘高比例新能源、电动汽车、储能电站等并网,迫切需要改进电网安全稳定控制技术体系,将海量分散可控资源纳入电网紧急控制范畴。针对紧急控制在线决策需求,该文给出以虚拟电厂(virtual power plant,VPP)为管控形式的分布式能源(distributed energy resources,DERs)紧急功率调节能力量化描述和在线评估方法。首先,分析紧急功率调节能力的内涵及表述要求,给出调节能力的量化描述方法;其次,构建反映物理特性及考虑用户行为约束的VPP紧急功率调节能力评估综合模型;最后,给出考虑状态转移及边界约束的紧急功率多时间尺度调节能力计算方法,设计相关仿真计算模块,并实现与PSS/E接口。以含300台电动汽车及1000台空调的VPP为例,仿真验证所述方法的有效性。
基金the Ministry of Education and Science of the Republic of Serbia for its support to this research through the ProjectⅢ-42004.
文摘We aim to systematically review challenges imposed by emerging distributed energy resources(DERs)to model in two basic distribution management system(DMS)online applications—power flow and short-circuit analysis,as well as to offer a systematic review of potential solutions.In the last decade,electronically coupled DERs became increasingly popular.DERs can employ a wide range of control strategies for power,current,or voltage control,in both normal and faulted conditions.Therefore,DERs cannot be modeled with the traditional PQ(load or generator bus)or PV(generator bus)bus types used for modeling synchronous and induction machines in online power flow calculations.Moreover,since fault currents of DERs are limited to predefined maximal values,electronically coupled DERs cannot be represented with traditional voltage source behind impedance models for online short-circuit calculation(SCC).However,most of the DMS software packages still use the traditional models to represent all DER types,including those that are electronically coupled.This paper shows that there will be large calculation errors in such practice,which make the system model an inadequate representation of the system.This will lead to serious errors in the management,control,and operation of distribution systems.Nonetheless,potential solutions to the challenges are systematically reviewed.Finally,the calculation results on a distribution test system with all DER types are used to prove the claim.
文摘分布式电源、电动汽车、温控负荷等需求侧可控异构分散资源渗透率逐步增加,迫切需要对其有效整合后参与电网调控。虚拟电厂(virtualpowerplant,VPP)是聚合和管控海量分布式能源(distributed energy resources,DERs)的有效形式,而运行仿真工具是发挥其作用的重要支撑。鉴于此,该文给出覆盖DER设备建模、异构DERs聚合和集群协同控制等全环节的VPP短时长精细化生产模拟方法,并设计面向VPP参与电网互动的开放式仿真系统。在分析VPP短时长精细化生产模拟需求的基础上,归纳精细化仿真关键技术;基于DERs物理特性分析及管控架构构建,提出包含设备层和管控层的VPP精细化建模方法;以通用开放为原则,设计仿真系统实现方案,通过模块化建模和通用化架构及互动接口设计,实现对多种电网仿真引擎和多类DERs模型兼容。以包含异构DERs的单个VPP为例,介绍典型日VPP生产模拟结果,并以包含多VPP的区域电网为例,给出DERs集群功率调节响应过程及其参与频率紧急控制和功角稳定紧急控制的效果,仿真结果验证了所述方法和系统的有效性。
基金supported by National Key Research and Development Program of China(No.2017YFF0108800)National Natural Science Foundation of China(Nos.61773109,6143304)Major Program of National Natural Foundation of China(No.61573094).
文摘An exponential-function-based droop control strategy for the distributed energy resources(DERs)is proposed to reduce the reactive power-sharing deviation,limit the minimum value of frequency/voltage,whilst improving the utilization rate of renewable energy.Both DERs and loads are interconnected to achieve a power exchange by converters,where the power management system should accurately share the active/reactive power demand.However,the proportional reactive power sharing often deteriorates due to its dependence on the line impedances.Thus,an exponential-function-based droop control is proposed to(1)prevent voltage and frequency from falling to the lower restraint,(2)achieve accurate reactive power sharing,(3)eliminate communication and improve the usage ratio of renewable energy.Furthermore,its stability is analyzed,and the application in islanded AC/DC hybrid microgrids is investigated to achieve the bidirectional power flow.The simulation and experimental results show that the reactive power sharing deviation can be reduced,and the utilization rate of renewable energy is improved by using the proposed method.Moreover,the simulation results illustrate that the system can maintain stable operation when the microgrid is switched from one supplied energy operation condition to another absorbed one.
文摘The high penetration of distributed energy resources (DERs) will significantly challenge the power system operation and control due to their stochastic, intermittent, and fluctuation characteristics. This enhances the difficulty of congestion management of power systems in cross-border electricity market among different regions. For handling this, the Real-Time Market is proposed for balancing capacity trading against congestions. Several strategies for Real-Time Market dealing with congestions are proposed. The strategy of two-stage crossborder markets in Day-ahead, Intra-day and Real Time Market are introduced with the congestion constraints complied. Pre-Contingency strategy is proposed as the advance preparation for the future congestion, and In-Day redispatch is used for regulation. Accordingly, the requirements on facilities considering telemetry and remote control in a fast manner are discussed at last.
文摘An economic evaluation of a network of distributed energy resources （DERs） comprising a microgrid structure of power delivery system in an Indian scenario has been made. The mathematical analysis is based on the application of tuned genetic algorithm （TGA）. The analyses for optimal power operation pertaining to minimum cost have been made for two cases in Indian power delivery system. The first case deals with the consumers＇ individual optimal operation of DERs, while in the second one, consumers altogether form a microgrid with the optimal supply of power from DERs. The total annual costs for these two cases are found to be economically competitive and encouraging. A reduction of approximately 5.7% in the annual cost has been obtained in the case of microgid system than that in the separately operating consumers＇ system for a small locality of India. It is observed that the application of TGA results in a reduction of the minimum cost depicting an improved outcome in terms of energy economy.
