风电机组的友好型调频控制对改善风电并网系统的频率响应特性具有重要作用。该文在分析最大功率跟踪(maximum power point tracking,MPPT)运行风电机组,利用变比例系数调速、飞轮储能基于功率调节实现频率支撑可行性的基础上,从优化风...风电机组的友好型调频控制对改善风电并网系统的频率响应特性具有重要作用。该文在分析最大功率跟踪(maximum power point tracking,MPPT)运行风电机组,利用变比例系数调速、飞轮储能基于功率调节实现频率支撑可行性的基础上,从优化风储系统频率响应特性出发,基于协同控制理论,提出飞轮储能协同MPPT运行风电机组提供频率响应的两层协同控制方案。通过将频率偏差和风电机组虚拟电气惯量线性组合构成宏变量,并利用宏变量的零输入响应控制流形,设计实现不同风速风电机组协同提供频率支撑的变比例系数调速策略。进一步,基于频率偏差、储能调频功率指令和风电机组虚拟惯量的线性组合构成宏变量,采用相同的控制流形设计飞轮储能协同风电机组提供频率支撑、快速恢复风电机组MPPT运行和避免频率二次扰动的附加调频有功调节策略。最后,利用风电并网系统的负荷频率扰动,验证所提协同控制的有效性,结果表明,该策略不仅有助于提高系统恢复同步稳定的动态特性,而且能够降低同步发电机参与调频的有功调节速度要求。展开更多
Ideally, diesel hybrid autonomous power systems would operate with high penetration of renewable energy sources such as wind and photovoltaic to minimize fuel consumption. However, since these are inherently intermitt...Ideally, diesel hybrid autonomous power systems would operate with high penetration of renewable energy sources such as wind and photovoltaic to minimize fuel consumption. However, since these are inherently intermittent and fluctuating, the grid-forming diesel engine generator sets are usually required to operate with larger amounts of spinning reserve, often at low loading conditions what tends to increases operating and maintenance costs. Frequency stability is of great concern in “small” systems, such as mini-grids, where any individual generator in-feed represents a substantial portion of the total demand. There, the initial rate of change of frequency is typically larger and a lower value of frequency can be reached in a shorter time than in conventional systems with all generation supplied by rotating machines, possibly resulting in under-frequency load shedding and tripping of renewable energy generators. The first part of this paper, discusses some general concepts regarding frequency stability in a diesel hybrid mini-grid and how energy storage systems can be used to enhance system performance. Then, a particular technique based on a virtual synchronous generator is presented and its effectiveness is demonstrated with simulation results.展开更多
When a microgrid is mainly supplied by renewable energy sources(RESs), the frequency deviations may deteriorate significantly the power quality delivered to the loads. This paper proposes a frequency-based control str...When a microgrid is mainly supplied by renewable energy sources(RESs), the frequency deviations may deteriorate significantly the power quality delivered to the loads. This paper proposes a frequency-based control strategy, ensuring the frequency among the strict limits imposed by the Standard EN 50160. The frequency of the microgrid common AC bus is determined by the energy storage converter, implementing a proposed droop curve among the state of charge(SoC) of the battery and the frequency. Therefore, the information of the SoC becomes known to every distributed energy resource(DER) of the microgrid and determines the active power injection of the converter-interfaced DERs. The active power injection of the rotating generators remains unaffected, while any mismatch among the power generation and consumption is absorbed by the energy storage system. Finally, in case of a solid short-circuit within the microgrid, the energy storage system detects the severe voltage decrease and injects a large current in order to clear the fault by activating the protection device closer to the fault. The proposed control methodology is applied in a microgrid with PVs, wind generators and a battery, while its effectiveness is evaluated by detailed simulation tests.展开更多
With rapidly growing of Renewable Energy Sources(RESs)in renewable power systems,several disturbances influence on the power systems such as;lack of system inertia that results from replacing the synchronous generator...With rapidly growing of Renewable Energy Sources(RESs)in renewable power systems,several disturbances influence on the power systems such as;lack of system inertia that results from replacing the synchronous generators with RESs and frequency/voltage fluctuations that resulting from the intermittent nature of the RESs.Hence,the modern power systems become more susceptible to the system instability than conventional power systems.Therefore,in this study,a new application of Superconducting Magnetic Energy Storage(SMES)(i.e.,auxiliary Load Frequency Control(LFC))has been integrated with the secondary frequency control(i.e.,LFC)for frequency stability enhancement of the Egyptian Power System(EPS)due to high RESs penetration.Where,the coordinated control strategy is based on the PI controller that is optimally designed by the Particle Swarm Optimization(PSO)algorithm to minimize the frequency deviations of the EPS.The EPS includes both conventional generation units(i.e.,non-reheat,reheat and hydraulic power plants)with inherent nonlinearities,and RESs(i.e.,wind and solar energy).System modelling and simulation results are carried out using Matlab/Simulink^(■)software.The simulation results reveal the robustness of the proposed coordinated control strategy to preserve the system stability of the EPS with high penetration of RESs for different contingencies.展开更多
针对油田"以电代油"的需求及现有2种电动修井机存在的问题,研制了XJ900DB新型网电修井机。该修井机将变频调速和超级电容储能技术相结合,在现有抽油机低压配电条件下(50 k VA/400 V),以超级电容器作为储能元件,利用修井机工...针对油田"以电代油"的需求及现有2种电动修井机存在的问题,研制了XJ900DB新型网电修井机。该修井机将变频调速和超级电容储能技术相结合,在现有抽油机低压配电条件下(50 k VA/400 V),以超级电容器作为储能元件,利用修井机工作间歇充电,起升时适时放电,补偿修井机输出功率,并采用变频调速和机械换挡,实现绞车宽恒功率输出,既保证新型修井机与常规修井机工作效率和作业能力相同,又可以安全、方便地实现修井机"电代油"。华北油田3个月的应用结果表明:应用XJ900DB新型网电修井机后共节省作业用燃油7.67 t,节省能耗费用2.88万元;该修井机可在各种恶劣气候下作业,工作稳定,性能可靠,电网供电、超级电容器模组充放电正常。XJ900DB新型网电修井机具有较高的推广应用价值。展开更多
文摘风电机组的友好型调频控制对改善风电并网系统的频率响应特性具有重要作用。该文在分析最大功率跟踪(maximum power point tracking,MPPT)运行风电机组,利用变比例系数调速、飞轮储能基于功率调节实现频率支撑可行性的基础上,从优化风储系统频率响应特性出发,基于协同控制理论,提出飞轮储能协同MPPT运行风电机组提供频率响应的两层协同控制方案。通过将频率偏差和风电机组虚拟电气惯量线性组合构成宏变量,并利用宏变量的零输入响应控制流形,设计实现不同风速风电机组协同提供频率支撑的变比例系数调速策略。进一步,基于频率偏差、储能调频功率指令和风电机组虚拟惯量的线性组合构成宏变量,采用相同的控制流形设计飞轮储能协同风电机组提供频率支撑、快速恢复风电机组MPPT运行和避免频率二次扰动的附加调频有功调节策略。最后,利用风电并网系统的负荷频率扰动,验证所提协同控制的有效性,结果表明,该策略不仅有助于提高系统恢复同步稳定的动态特性,而且能够降低同步发电机参与调频的有功调节速度要求。
文摘Ideally, diesel hybrid autonomous power systems would operate with high penetration of renewable energy sources such as wind and photovoltaic to minimize fuel consumption. However, since these are inherently intermittent and fluctuating, the grid-forming diesel engine generator sets are usually required to operate with larger amounts of spinning reserve, often at low loading conditions what tends to increases operating and maintenance costs. Frequency stability is of great concern in “small” systems, such as mini-grids, where any individual generator in-feed represents a substantial portion of the total demand. There, the initial rate of change of frequency is typically larger and a lower value of frequency can be reached in a shorter time than in conventional systems with all generation supplied by rotating machines, possibly resulting in under-frequency load shedding and tripping of renewable energy generators. The first part of this paper, discusses some general concepts regarding frequency stability in a diesel hybrid mini-grid and how energy storage systems can be used to enhance system performance. Then, a particular technique based on a virtual synchronous generator is presented and its effectiveness is demonstrated with simulation results.
文摘When a microgrid is mainly supplied by renewable energy sources(RESs), the frequency deviations may deteriorate significantly the power quality delivered to the loads. This paper proposes a frequency-based control strategy, ensuring the frequency among the strict limits imposed by the Standard EN 50160. The frequency of the microgrid common AC bus is determined by the energy storage converter, implementing a proposed droop curve among the state of charge(SoC) of the battery and the frequency. Therefore, the information of the SoC becomes known to every distributed energy resource(DER) of the microgrid and determines the active power injection of the converter-interfaced DERs. The active power injection of the rotating generators remains unaffected, while any mismatch among the power generation and consumption is absorbed by the energy storage system. Finally, in case of a solid short-circuit within the microgrid, the energy storage system detects the severe voltage decrease and injects a large current in order to clear the fault by activating the protection device closer to the fault. The proposed control methodology is applied in a microgrid with PVs, wind generators and a battery, while its effectiveness is evaluated by detailed simulation tests.
基金This paper was funded by the Cultural Affairs and Missions Sector of the Egyptian Ministry of Higher Education.
文摘With rapidly growing of Renewable Energy Sources(RESs)in renewable power systems,several disturbances influence on the power systems such as;lack of system inertia that results from replacing the synchronous generators with RESs and frequency/voltage fluctuations that resulting from the intermittent nature of the RESs.Hence,the modern power systems become more susceptible to the system instability than conventional power systems.Therefore,in this study,a new application of Superconducting Magnetic Energy Storage(SMES)(i.e.,auxiliary Load Frequency Control(LFC))has been integrated with the secondary frequency control(i.e.,LFC)for frequency stability enhancement of the Egyptian Power System(EPS)due to high RESs penetration.Where,the coordinated control strategy is based on the PI controller that is optimally designed by the Particle Swarm Optimization(PSO)algorithm to minimize the frequency deviations of the EPS.The EPS includes both conventional generation units(i.e.,non-reheat,reheat and hydraulic power plants)with inherent nonlinearities,and RESs(i.e.,wind and solar energy).System modelling and simulation results are carried out using Matlab/Simulink^(■)software.The simulation results reveal the robustness of the proposed coordinated control strategy to preserve the system stability of the EPS with high penetration of RESs for different contingencies.
文摘针对油田"以电代油"的需求及现有2种电动修井机存在的问题,研制了XJ900DB新型网电修井机。该修井机将变频调速和超级电容储能技术相结合,在现有抽油机低压配电条件下(50 k VA/400 V),以超级电容器作为储能元件,利用修井机工作间歇充电,起升时适时放电,补偿修井机输出功率,并采用变频调速和机械换挡,实现绞车宽恒功率输出,既保证新型修井机与常规修井机工作效率和作业能力相同,又可以安全、方便地实现修井机"电代油"。华北油田3个月的应用结果表明:应用XJ900DB新型网电修井机后共节省作业用燃油7.67 t,节省能耗费用2.88万元;该修井机可在各种恶劣气候下作业,工作稳定,性能可靠,电网供电、超级电容器模组充放电正常。XJ900DB新型网电修井机具有较高的推广应用价值。
