以含微网的配电网可靠性评估为研究内容,首先对光伏发电和风力发电出力随机特性进行了研究,建立了分布式电源和储能联合发电系统的可靠性模型。在此基础上,基于蒙特卡罗时序模拟方法,提出了含微网的配电网可靠性评估算法。最后采用所提...以含微网的配电网可靠性评估为研究内容,首先对光伏发电和风力发电出力随机特性进行了研究,建立了分布式电源和储能联合发电系统的可靠性模型。在此基础上,基于蒙特卡罗时序模拟方法,提出了含微网的配电网可靠性评估算法。最后采用所提出的模型和算法对IEEE DRTS Bus 4改进系统进行了评估。算例评估结果表明,微网能有效提高配电系统的供电可靠性。展开更多
Auxiliary frequency control of a wind turbine generator(WTG) has been widely used to enhance the frequencysecurity of power systems with high penetration of renewableenergy. Previous studies recommend two types of con...Auxiliary frequency control of a wind turbine generator(WTG) has been widely used to enhance the frequencysecurity of power systems with high penetration of renewableenergy. Previous studies recommend two types of control schemes,including frequency droop control and emulated inertia control,which simulate the response characteristics of the synchronousgenerator (SG). This paper plans to further explore the optimalauxiliary frequency control of the wind turbine based on previousresearch. First, it is determined that the virtual inertia control haslittle effect on the maximum rate of change of frequency (MaxROCOF)if the time delay of the control link of WTG is taken intoconsideration. Secondly, if a WTG operates in maximum powerpoint tracking (MPPT) mode and uses the rotor deceleration forfrequency modulation, its optimal auxiliary frequency control willcontain only droop control. Furthermore, if the droop control isproperly delayed, better system frequency response (SFR) willbe obtained. The reason is that coordination between the WTGand SG is important for SFR when the frequency modulationcapability of the WTG is limited. The frequency modulationcapability of the WTG is required to be released more properly.Therefore, when designing optimal auxiliary frequency controlfor the WTG, a better control scheme is worth further study.展开更多
为有效提高风电场的并网运行能力,将电池储能系统(battery energy storage system,BESS)-静止同步补偿器(static compensator,STATCOM)串联集成单元与风力发电单元相结合,建立基于Park变换的BESS-STATCOM集成单元和基于异步发电机风力...为有效提高风电场的并网运行能力,将电池储能系统(battery energy storage system,BESS)-静止同步补偿器(static compensator,STATCOM)串联集成单元与风力发电单元相结合,建立基于Park变换的BESS-STATCOM集成单元和基于异步发电机风力发电系统的整体动态数学模型,通过理论推导和基于仿真平台PSCAD对不同风速时风电场的出力及并网点的电压进行计算,结果表明,BESS-STATCOM集成单元具有快速功率调节能力,使风力发电单元可作为调度机组单元运行;在求解包含风电场的电力系统潮流时,可以将其视为PV节点,而且能够显著提高电网的运行稳定性和供电可靠性。展开更多
The Photovoltaic(PV)plants are significantly different from the conventional synchronous generators in terms of physical and electrical characteristics,as it connects to the power grid through the voltage-source conve...The Photovoltaic(PV)plants are significantly different from the conventional synchronous generators in terms of physical and electrical characteristics,as it connects to the power grid through the voltage-source converters.High penetration PV in power system will bring several critical challenges to the safe operation of power grid including transient stability.To address this problem,the paper proposes a control strategy to help the PVs work like a synchronous generator with variable inertia by energy storage system(ESS).First,the overall control strategy of the PV-based virtual synchronous generator(PV-VSG)is illustrated.Then the control strategies for the variable inertia of the PV-VSG are designed to attenuate the transient energy of the power system after the fault.Simulation results of a simple power system show that the PV-VSG could utilize the energy preserved in the ESS to balance the transient energy variation of power grid after fault and improve the transient stability of the power system.展开更多
Future power systems face several challenges.One of them is the use of high power converters that decouple new energy sources from the AC power grid.This situation decreases the total system inertia affecting its abil...Future power systems face several challenges.One of them is the use of high power converters that decouple new energy sources from the AC power grid.This situation decreases the total system inertia affecting its ability to overcome system frequency disturbances.The wind power industry has created several controllers to enable inertial response on wind turbines generators:artificial,emulated,simulated,or synthetic inertial.This paper deals with the issues related to the emulated inertia of wind turbines based on full-converters and their effect on the under-frequency protection schemes during the recovery period after system frequency disturbances happen.The main contribution of this paper is to demonstrate the recovery period of under-frequency transients in future power systems which integrate wind turbines with emulated inertia capability does not completely avoid the worse scenarios in terms of under-frequency load shedding.The extra power delivered from a wind turbine during frequency disturbances can substantially reduce the rate of frequency change.Thus it provides time for the active governors to respond.展开更多
文摘以含微网的配电网可靠性评估为研究内容,首先对光伏发电和风力发电出力随机特性进行了研究,建立了分布式电源和储能联合发电系统的可靠性模型。在此基础上,基于蒙特卡罗时序模拟方法,提出了含微网的配电网可靠性评估算法。最后采用所提出的模型和算法对IEEE DRTS Bus 4改进系统进行了评估。算例评估结果表明,微网能有效提高配电系统的供电可靠性。
基金the National Natural Science Foundation of China(51922061)the Science and Technology Project of State Grid Corporation of China(SGZJ0000KXJS1900418).
文摘Auxiliary frequency control of a wind turbine generator(WTG) has been widely used to enhance the frequencysecurity of power systems with high penetration of renewableenergy. Previous studies recommend two types of control schemes,including frequency droop control and emulated inertia control,which simulate the response characteristics of the synchronousgenerator (SG). This paper plans to further explore the optimalauxiliary frequency control of the wind turbine based on previousresearch. First, it is determined that the virtual inertia control haslittle effect on the maximum rate of change of frequency (MaxROCOF)if the time delay of the control link of WTG is taken intoconsideration. Secondly, if a WTG operates in maximum powerpoint tracking (MPPT) mode and uses the rotor deceleration forfrequency modulation, its optimal auxiliary frequency control willcontain only droop control. Furthermore, if the droop control isproperly delayed, better system frequency response (SFR) willbe obtained. The reason is that coordination between the WTGand SG is important for SFR when the frequency modulationcapability of the WTG is limited. The frequency modulationcapability of the WTG is required to be released more properly.Therefore, when designing optimal auxiliary frequency controlfor the WTG, a better control scheme is worth further study.
文摘为有效提高风电场的并网运行能力,将电池储能系统(battery energy storage system,BESS)-静止同步补偿器(static compensator,STATCOM)串联集成单元与风力发电单元相结合,建立基于Park变换的BESS-STATCOM集成单元和基于异步发电机风力发电系统的整体动态数学模型,通过理论推导和基于仿真平台PSCAD对不同风速时风电场的出力及并网点的电压进行计算,结果表明,BESS-STATCOM集成单元具有快速功率调节能力,使风力发电单元可作为调度机组单元运行;在求解包含风电场的电力系统潮流时,可以将其视为PV节点,而且能够显著提高电网的运行稳定性和供电可靠性。
文摘The Photovoltaic(PV)plants are significantly different from the conventional synchronous generators in terms of physical and electrical characteristics,as it connects to the power grid through the voltage-source converters.High penetration PV in power system will bring several critical challenges to the safe operation of power grid including transient stability.To address this problem,the paper proposes a control strategy to help the PVs work like a synchronous generator with variable inertia by energy storage system(ESS).First,the overall control strategy of the PV-based virtual synchronous generator(PV-VSG)is illustrated.Then the control strategies for the variable inertia of the PV-VSG are designed to attenuate the transient energy of the power system after the fault.Simulation results of a simple power system show that the PV-VSG could utilize the energy preserved in the ESS to balance the transient energy variation of power grid after fault and improve the transient stability of the power system.
文摘Future power systems face several challenges.One of them is the use of high power converters that decouple new energy sources from the AC power grid.This situation decreases the total system inertia affecting its ability to overcome system frequency disturbances.The wind power industry has created several controllers to enable inertial response on wind turbines generators:artificial,emulated,simulated,or synthetic inertial.This paper deals with the issues related to the emulated inertia of wind turbines based on full-converters and their effect on the under-frequency protection schemes during the recovery period after system frequency disturbances happen.The main contribution of this paper is to demonstrate the recovery period of under-frequency transients in future power systems which integrate wind turbines with emulated inertia capability does not completely avoid the worse scenarios in terms of under-frequency load shedding.The extra power delivered from a wind turbine during frequency disturbances can substantially reduce the rate of frequency change.Thus it provides time for the active governors to respond.
