Dynamics and Stability of Meshed Multiterminal HVDC Networks
Dynamics and Stability of Meshed Multiterminal HVDC Networks
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DOI：
10.1109/tpwrs.2018.2889516
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发表时间：
2018-03
影响因子：
6.6
通讯作者：
S. Sanchez;A. Garcés;Gilbert Bergna-Diaz;E. Tedeschi
中科院分区：
文献类型：
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作者：
S. Sanchez;A. Garcés;Gilbert Bergna-Diaz;E. Tedeschi
本文研究了多端高压直流输电网平衡点的存在性，评估其唯一性，并定义了条件，以确保其稳定性。一个海上多端高压直流系统，包括两个风电场被选为应用测试案例。首先，利用多重图理论建立了网络的广义动态模型。这样的模型捕获的传输线和电缆的频率依赖性，它是非线性的，由于恒定的功率行为的转换器终端使用下垂调节，并提出了一个适当程度的简化的模块化多电平转换器，在给定的条件下，允许系统级的研究在潜在的大型网络。在此模型的基础上，通过将分析归结为一个潮流问题，利用Banach不动点定理，证明了平衡点的存在唯一性。此外，平衡的稳定性进行了分析，通过获得一个李雅普诺夫函数的Krasovskii定理。所选四端高压直流电网的计算结果证实了平衡点的存在性和稳定性的要求。
This paper investigates the existence of an equilibrium point in multiterminal HVdc grids, assesses its uniqueness, and defines conditions to ensure its stability. An offshore multiterminal HVdc system including two wind farms is selected as an application test case. At first, a generalized dynamic model of the network is proposed, using multigraph theory. Such model captures the frequency dependence of transmission lines and cables; it is nonlinear due to the constant power behavior of the converter terminals using droop regulation, and presents a suitable degree of simplifications of the modular multilevel converters, under given conditions, to allow system level studies over potentially large networks. Based on this model, the existence and uniqueness of the equilibrium point are demonstrated by returning the analysis to a load-flow problem and using the Banach fixed point theorem. Additionally, the stability of the equilibrium is analyzed by obtaining a Lyapunov function by the Krasovskii's theorem. Computational results obtained for the selected four-terminal HVdc grid corroborate the requirement for the existence and stability of the equilibrium point.