摘要
在向海岛无源网络供电的VSC-HVDC输电系统中,由于逆变站的恒功率特性,以及整流站与逆变站间直流侧阻抗交互的影响,易使VSC-HVDC输电系统的直流侧发生振荡甚至失稳。对此,该文针对整流站提出了一种虚拟阻感性阻抗稳定性控制方法,能有效抑制VSC-HVDC输电系统的直流侧振荡,且不影响逆变站向海岛负荷供电的动态性能。基于所提控制方法,建立了海岛VSC-HVDC输电系统的小信号直流阻抗模型,其包括整流站输出阻抗模型、直流电缆阻抗模型和逆变站的输入阻抗模型。根据Nyquist判据和伯德图揭示了整流站采用传统虚拟电阻稳定性控制在抑制VSC-HVDC输电系统直流侧振荡失效的根本原因：即整流站的等效输出阻抗在电压控制带宽外恶化成负阻性,削弱了系统阻尼。所提振荡抑制方法通过阻感性阻抗的相角超前特性能校正整流站的等效输出阻抗为正阻性,可有效改善系统的稳定性。最后,仿真和实验验证了该文的分析和所提控制方法的有效性。
In the VSC-HVDC system supplying power to passive network on the island, the DC-side of the system is prone to oscillation and even instability, which is resulted from the constant power characteristic of the inverter station and the interaction between the DC-side impedance of the rectifier and inverter stations. To this issue, a virtual resistive-inductive impedance stability control strategy aiming at rectifier station was proposed. This control strategy can effectively mitigate the DC-side oscillation of the VSC-HVDC system without affecting the load performance of the inverter station. Based on the proposed control strategy, the DC impedance model of the maritime VSC-HVDC system was built, including the output impedance of the rectifier station, DC cable impedance and the input impedance of the inverter station. The reason why rectifier station fails to mitigate the DC-side oscillation of the VSC-HVDC system using traditional virtual resistance stability control was revealed by the Nyquist criterion and the Bode plot. The equivalent output impedance of the rectifier station turns into negative resistance outside the voltage control bandwidth, thus decreasing the system damping. The proposed strategy can correct the equivalent output impedance to be positive using the phase-lead characteristic of the inductive impedance, improving system stability. Finally, simulation and experiment results validate the proposed control strategy and analysis.
作者
伍文华
陈燕东
罗安
周乐明
周小平
杨苓
黄旭程
WU Wenhua;CHEN Yandong;LUO An;ZHOU Leming;ZHOU Xiaoping;YANG Ling;HUANG Xucheng(National Electric Power Conversion and Control Engineering Technology Research Center（Hunan University）,Changsha 410082,Hunan Province,China)
出处
《中国电机工程学报》
EI
CSCD
北大核心
2018年第15期4359-4368,共10页
Proceedings of the CSEE
基金
国家重点研发计划项目(2017YFB0902000)
国家电网公司科技项目(SGXJ0000KXJS1700841)
湖南省博士生科研创新项目(CX2017B104)~~
