付媛, 邵馨玉, 李浩. 直流配电网的暂态电压稳定控制策略[J]. 高电压技术, 2021, 47(4): 1354-1362. DOI: 10.13336/j.1003-6520.hve.20200040
引用本文: 付媛, 邵馨玉, 李浩. 直流配电网的暂态电压稳定控制策略[J]. 高电压技术, 2021, 47(4): 1354-1362. DOI: 10.13336/j.1003-6520.hve.20200040
FU Yuan, SHAO Xinyu, LI Hao. Transient Voltage Stability Control Strategy of DC Distribution Network[J]. High Voltage Engineering, 2021, 47(4): 1354-1362. DOI: 10.13336/j.1003-6520.hve.20200040
Citation: FU Yuan, SHAO Xinyu, LI Hao. Transient Voltage Stability Control Strategy of DC Distribution Network[J]. High Voltage Engineering, 2021, 47(4): 1354-1362. DOI: 10.13336/j.1003-6520.hve.20200040

直流配电网的暂态电压稳定控制策略

Transient Voltage Stability Control Strategy of DC Distribution Network

  • 摘要: 新能源与负荷侧换流器在短时电压振荡中的恒功率控制将表现出负阻抗特性,削弱直流电网阻尼,容易诱发直流电压持续性振荡。首先建立下垂控制下直流配电网的暂态电压稳定模型,阐述直流电压惯量与阻尼的定义,分析影响系统暂态特性的关键因素。其次,提出通过引入直流母线电压变化量,动态调整下垂系数,增强直流电压阻尼的控制策略。针对阻尼控制策略带来的直流压降增大的问题,通过改进直流母线电压外环控制,使其与电压阻尼控制策略结合,提出暂态电压稳定控制策略,不仅可以提高系统阻尼,并在电压振荡抑制后减小阻尼控制引起的电压偏差。最后,通过搭建六端直流仿真系统,验证所提控制策略可以有效抑制系统振荡,并可减小振荡后的电压偏差,显著提高系统暂态电压稳定性。

     

    Abstract: The constant power control of new energy and load side converters in short-term voltage oscillations will show negative impedance characteristics, weaken the damping of DC power grid, and easily induce continuous DC voltage oscillations. We firstly establish a transient stability model of DC distribution network under droop control, expound the definition of DC voltage inertia and damping, and analyze the key factors influencing the transient characteristics of the system. Secondly, we propose a control strategy that the DC bus voltage variation is introduced to dynamically adjust the droop coefficient and enhance DC voltage damping. In view of the increase of DC voltage drop caused by the damping control strategy, a transient voltage stability control strategy is proposed by improving the DC bus voltage outer loop control and combining it with the voltage damping control strategy, which can not only improve the system damping, but also reduce the voltage deviation caused by the damping control after the voltage oscillation is suppressed. Finally, a six-terminal DC simulation system is built to verify that the proposed control strategy can effectively suppress the system oscillation, reduce the voltage deviation after oscillation, and significantly improve the transient stability of the system.

     

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