| 摘要: |
| 电压源型变换器(Voltage Source Converter, VSC)作为新能源发电的并网接口广泛地应用于电力系统。以单台VSC经线路阻抗并入无穷大电网为例，推导弱电网下VSC功率输出特性。基于VSC系统阻尼转矩模型得出阻尼系数直接决定系统静态稳定，同步系数通过影响阻尼功率相位间接影响系统稳定。根据阻尼功率与同步功率之间的相位关系解释了VSC系统静态失稳机理，并且利用Bode图研究了系统参数与运行工况对系统稳定性影响。结果表明，电流环比例增益越低、锁相环带宽越窄或无功功率运行不合理，VSC系统将面临静态失稳风险。同时在Matlab/Simulink中搭建VSC并入弱电网模型，验证了理论分析的正确性。 |
| 关键词: 电压源型变换器 静态稳定性 功率特性方程 阻尼转矩模型 |
| DOI：DOI: 10.19783/j.cnki.pspc.201080 |
| 投稿时间：2020-10-03修订日期：2020-03-15 |
| 基金项目:内蒙古自治区自然科学基金项目资助(2016BS05 08)；内蒙古自治区研究生科研创新项目资助(S20191142Z) |
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| Static stability analysis of voltage source converters connected to a weak grid |
| ZHENG Chaohang,LI Hua |
| (College of Electric Engineering, Inner Mongolia University of Technology, Hohhot 010010, China) |
| Abstract: |
| A Voltage Source Converter (VSC), as a grid connection interface for new energy generation, is widely used in power systems. A single VSC connected to an infinite grid via line impedance is built as a typical system. The output active power characteristics of the VSC under a weak grid condition are studied. On this basis, the damping and torque model of VSC system is established, and the damping coefficient directly determines the static stability of the system. The synchronizing coefficient indirectly affects the system stability by affecting the damping power phase. According to the phase relationship between the damping power and the synchronous power, the static stability of the VSC system is explained, and the influence of the parameters and operating conditions on the system stability is studied using the Bode diagram. It is indicated that the lower the current loop proportional gain, the narrower the PLL bandwidth. With unreasonable reactive power operation, the VSC system will face the risk of static instability. The grid-tied VSC system is built on Matlab/Simulink to verify the correctness of the theoretical analysis.
This work is supported by the Natural Science Foundation of Inner Mongolia Autonomous Region (No. 2016BS0508) and Graduate Scientific Research Innovation of Inner Mongolia Autonomous Region (No. S20191142Z). |
| Key words: voltage source converter (VSC) static stability power characteristics equation damping and torque model |
