近年来,抽水蓄能电站发展迅猛,抽水蓄能电站在稳定系统电压方面有着优越的性能,因此抽水蓄能电站自动电压控制(AVC-Automatic Voltage Control)是非常有意义的。本文介绍了宜兴抽水蓄能电站一次接线方式、机组运行方式和机组出力能力;...近年来,抽水蓄能电站发展迅猛,抽水蓄能电站在稳定系统电压方面有着优越的性能,因此抽水蓄能电站自动电压控制(AVC-Automatic Voltage Control)是非常有意义的。本文介绍了宜兴抽水蓄能电站一次接线方式、机组运行方式和机组出力能力;根据抽水蓄能机组特性,论述了抽水蓄能机组无功功率出力能力限制。结合抽水蓄能电站的运行工况,探讨了其自动电压控制的基本思想和控制原则。展开更多
Impedance analysis is an effective method to analyze the oscillation issue associated with grid-connected photovoltaic systems.However,the existing impedance modeling of a gridconnected photovoltaic inverter usually o...Impedance analysis is an effective method to analyze the oscillation issue associated with grid-connected photovoltaic systems.However,the existing impedance modeling of a gridconnected photovoltaic inverter usually only considers the effect of a single perturbation frequency,ignoring the coupling frequency response between the internal control loops of a grid-connected inverter,which severely affects the accuracy of the stability analysis.Hence,a method of impedance modeling and stability analysis for grid-connected photovoltaic inverters considering cross-coupling frequency is proposed in this paper.First,the generation mechanism of frequency coupling in gridconnected photovoltaic inverters,and the relationship between the coupling frequency and perturbation frequency are analyzed.Secondly,a sequence impedance model of grid-connected photovoltaic systems considering the coupling frequency is established by using the harmonic linearization method.The impact of DC bus voltage control strategy on frequency coupling characteristics of a grid-connected photovoltaic system is evaluated,and the impact of a coupling frequency term on system stability is quantitatively analyzed.Finally,the advantages of the proposed method are verified by several simulations.The results show that the proposed impedance model can accurately predict the potential resonance points of the system,and the coupling frequency characteristics will become much stronger with smaller DC bus capacitance or larger bandwidth of the DC bus controller.展开更多
文摘近年来,抽水蓄能电站发展迅猛,抽水蓄能电站在稳定系统电压方面有着优越的性能,因此抽水蓄能电站自动电压控制(AVC-Automatic Voltage Control)是非常有意义的。本文介绍了宜兴抽水蓄能电站一次接线方式、机组运行方式和机组出力能力;根据抽水蓄能机组特性,论述了抽水蓄能机组无功功率出力能力限制。结合抽水蓄能电站的运行工况,探讨了其自动电压控制的基本思想和控制原则。
文摘Impedance analysis is an effective method to analyze the oscillation issue associated with grid-connected photovoltaic systems.However,the existing impedance modeling of a gridconnected photovoltaic inverter usually only considers the effect of a single perturbation frequency,ignoring the coupling frequency response between the internal control loops of a grid-connected inverter,which severely affects the accuracy of the stability analysis.Hence,a method of impedance modeling and stability analysis for grid-connected photovoltaic inverters considering cross-coupling frequency is proposed in this paper.First,the generation mechanism of frequency coupling in gridconnected photovoltaic inverters,and the relationship between the coupling frequency and perturbation frequency are analyzed.Secondly,a sequence impedance model of grid-connected photovoltaic systems considering the coupling frequency is established by using the harmonic linearization method.The impact of DC bus voltage control strategy on frequency coupling characteristics of a grid-connected photovoltaic system is evaluated,and the impact of a coupling frequency term on system stability is quantitatively analyzed.Finally,the advantages of the proposed method are verified by several simulations.The results show that the proposed impedance model can accurately predict the potential resonance points of the system,and the coupling frequency characteristics will become much stronger with smaller DC bus capacitance or larger bandwidth of the DC bus controller.
