In view of the variable parameters that affect the transient stability of electromagnetic torque and mechanical torque balance in AC-DC system,and the uncertainty of wind power in large-scale interconnection of wind f...In view of the variable parameters that affect the transient stability of electromagnetic torque and mechanical torque balance in AC-DC system,and the uncertainty of wind power in large-scale interconnection of wind farm.This paper proposes a linear parameter varying(LPV)robust feedback control method for transient stability of interconnected systems.The proposed LPV robust feedback control method uses the DC channel power control and the mechanical power in the interconnected system as the control target to improve the transient stability of the interconnected system with wind farm channel.Firstly,aiming at the strong nonlinear characteristics of the interconnected system,the power balance and the wind power output uncertainty in the transient process,the transient process is designed as a linear model of variable parameters.Then,the H∞robust output feedback controller is designed according to the LPV model.The transient stability control strategy topology and transfer function of the interconnected system are proposed.Finally,the proposed scheme is verified by an interconnected system formed by four equal-value grids through AC and DC lines in a digital simulation platform.The results show that the LPV robust feedback control model proposed in this paper has better response characteristics and transient stability control effects for interconnected systems with wind power weak sendingend system.展开更多
针对交直流系统暂态功角稳定问题,基于自抗扰控制理论研究,提出了电压源型换流器的柔性直流输电技术(voltage source converter based high voltage direct current,VSC-HVDC)有功调制控制策略。根据VSCHVDC对同步机组的可控能力筛选机...针对交直流系统暂态功角稳定问题,基于自抗扰控制理论研究,提出了电压源型换流器的柔性直流输电技术(voltage source converter based high voltage direct current,VSC-HVDC)有功调制控制策略。根据VSCHVDC对同步机组的可控能力筛选机组并确定聚合权重,将同步机群聚合转化为等效可控系统,利用线性自抗扰控制理论设计暂态稳定控制器;同时对同步机组的转速差和不平衡功率进行调制,从而充分发挥稳定控制器调节能力并维持交直流系统稳定。结果表明,控制器无需同步机组和直流输电系统的详细模型信息,且能适应系统运行方式的变化,并通过改进的IEEE39节点系统仿真验证了所提控制器的有效性和鲁棒性。展开更多
In recent years,the penetration of renewable resources into AC power systems has increased tremendously,creating a significantly impact on the latter’s operations and stability.In this respect,it is also important to...In recent years,the penetration of renewable resources into AC power systems has increased tremendously,creating a significantly impact on the latter’s operations and stability.In this respect,it is also important to gain a basic analytical understanding of such impact on the steady-state stability of power systems with electrically weak AC/DC interconnections,but such works are not very evident in the literature.Therefore,a classical analytic model of the single and multi-infeed HVDC system which now incorporates renewable resources is proposed.Then the well-established concept of voltage sensitivity of the AC/DC interconnection is applied to analyze the impact of the renewable resources on the steady-state stability of these composite system models,as well as on the influence of system conditions and parameters.This impact is also compared with that arising from other types of shunt devices alternatively connected at the same AC/DC interconnection,therefore their relative beneficial or negative impacts will also be benchmarked.展开更多
多直流送端系统内某一直流线路发生闭锁故障后,可以通过对其他非故障直流进行紧急功率支援(emergency DC power support,EDCPS)控制来提升系统受扰后的稳定性。如何有效量化EDCPS对系统稳定性的改善效果,从而提高安稳控制的效率,目前缺...多直流送端系统内某一直流线路发生闭锁故障后,可以通过对其他非故障直流进行紧急功率支援(emergency DC power support,EDCPS)控制来提升系统受扰后的稳定性。如何有效量化EDCPS对系统稳定性的改善效果,从而提高安稳控制的效率,目前缺少相应的指标;现有研究也尚未解决如何利用EDCPS最大程度提升多直流综合送出能力的问题。应用扩展等面积法(extended equal area criterion,EEAC)定量分析了EDCPS提升多直流送端系统暂态稳定性的机理;以两送出直流系统为例,推导了基于EEAC的暂态稳定裕度η对EDCPS的灵敏度公式;在此基础上,提出一种在不增加相关设备投入的前提下利用系统中现有稳控措施并结合暂态稳定裕度灵敏度的多直流送出能力提升控制方法,通过计算备选直流的暂态稳定裕度灵敏度,可以完整反映系统在遭受大扰动后的动态特性以及定量评估EDCPS对系统受扰后稳定性的改善效果,避免过去仅凭运行人员经验选取支援直流的问题,提高计算效率;最后,选取西北电网实际算例对所提出的多直流送出能力提升控制方法有效性进行仿真验证,以期为从事交直流混联电力系统稳定性分析与控制的学者和工程师们提供有益的参考。展开更多
基金This study was supported in part by the National Key R&D Program of China(2017YFB0902100).
文摘In view of the variable parameters that affect the transient stability of electromagnetic torque and mechanical torque balance in AC-DC system,and the uncertainty of wind power in large-scale interconnection of wind farm.This paper proposes a linear parameter varying(LPV)robust feedback control method for transient stability of interconnected systems.The proposed LPV robust feedback control method uses the DC channel power control and the mechanical power in the interconnected system as the control target to improve the transient stability of the interconnected system with wind farm channel.Firstly,aiming at the strong nonlinear characteristics of the interconnected system,the power balance and the wind power output uncertainty in the transient process,the transient process is designed as a linear model of variable parameters.Then,the H∞robust output feedback controller is designed according to the LPV model.The transient stability control strategy topology and transfer function of the interconnected system are proposed.Finally,the proposed scheme is verified by an interconnected system formed by four equal-value grids through AC and DC lines in a digital simulation platform.The results show that the LPV robust feedback control model proposed in this paper has better response characteristics and transient stability control effects for interconnected systems with wind power weak sendingend system.
文摘针对交直流系统暂态功角稳定问题,基于自抗扰控制理论研究,提出了电压源型换流器的柔性直流输电技术(voltage source converter based high voltage direct current,VSC-HVDC)有功调制控制策略。根据VSCHVDC对同步机组的可控能力筛选机组并确定聚合权重,将同步机群聚合转化为等效可控系统,利用线性自抗扰控制理论设计暂态稳定控制器;同时对同步机组的转速差和不平衡功率进行调制,从而充分发挥稳定控制器调节能力并维持交直流系统稳定。结果表明,控制器无需同步机组和直流输电系统的详细模型信息,且能适应系统运行方式的变化,并通过改进的IEEE39节点系统仿真验证了所提控制器的有效性和鲁棒性。
文摘In recent years,the penetration of renewable resources into AC power systems has increased tremendously,creating a significantly impact on the latter’s operations and stability.In this respect,it is also important to gain a basic analytical understanding of such impact on the steady-state stability of power systems with electrically weak AC/DC interconnections,but such works are not very evident in the literature.Therefore,a classical analytic model of the single and multi-infeed HVDC system which now incorporates renewable resources is proposed.Then the well-established concept of voltage sensitivity of the AC/DC interconnection is applied to analyze the impact of the renewable resources on the steady-state stability of these composite system models,as well as on the influence of system conditions and parameters.This impact is also compared with that arising from other types of shunt devices alternatively connected at the same AC/DC interconnection,therefore their relative beneficial or negative impacts will also be benchmarked.
文摘多直流送端系统内某一直流线路发生闭锁故障后,可以通过对其他非故障直流进行紧急功率支援(emergency DC power support,EDCPS)控制来提升系统受扰后的稳定性。如何有效量化EDCPS对系统稳定性的改善效果,从而提高安稳控制的效率,目前缺少相应的指标;现有研究也尚未解决如何利用EDCPS最大程度提升多直流综合送出能力的问题。应用扩展等面积法(extended equal area criterion,EEAC)定量分析了EDCPS提升多直流送端系统暂态稳定性的机理;以两送出直流系统为例,推导了基于EEAC的暂态稳定裕度η对EDCPS的灵敏度公式;在此基础上,提出一种在不增加相关设备投入的前提下利用系统中现有稳控措施并结合暂态稳定裕度灵敏度的多直流送出能力提升控制方法,通过计算备选直流的暂态稳定裕度灵敏度,可以完整反映系统在遭受大扰动后的动态特性以及定量评估EDCPS对系统受扰后稳定性的改善效果,避免过去仅凭运行人员经验选取支援直流的问题,提高计算效率;最后,选取西北电网实际算例对所提出的多直流送出能力提升控制方法有效性进行仿真验证,以期为从事交直流混联电力系统稳定性分析与控制的学者和工程师们提供有益的参考。
