Global Analysis of Synchronization Performance for Power Systems: Bridging the Theory-Practice Gap
Global Analysis of Synchronization Performance for Power Systems: Bridging the Theory-Practice Gap
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DOI：
10.1109/tac.2019.2942536
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发表时间：
2019-05
影响因子：
6.8
通讯作者：
F. Paganini;Enrique Mallada
中科院分区：
文献类型：
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作者：
F. Paganini;Enrique Mallada
随着具有不同动态的新能源的出现，电网中的同步问题正重新受到关注。已经提出了全球指标来评估性能，并在高度简化的假设下进行计算。在本文中，我们将这种方法扩展到更现实的网络场景，并将其与电力工程实践中使用的指标更紧密地联系起来。特别是，我们的分析涵盖了网络与发电机的异构评级和更丰富的动态模型的机器。在适当的参数比例假设下，我们证明了母线频率的阶跃响应可以分解为两个分量。第一个分量是捕获聚合电网行为的系统范围的频率，并且残差分量表示与聚合的单独总线频率偏差。使用这种分解，我们定义和计算在封闭的形式，捕捉动力工程师的相关动态行为的几个指标。特别是，使用系统频率，我们定义了行业风格的指标（最低点，RoCoF），通过代表性的机器进行评估。我们进一步使用剩余分量的范数来定义同步成本，该同步成本可以适当地量化区域间振荡。最后，我们采用鲁棒性分析工具来评估我们的比例假设的偏差。我们发现，系统频率仍然捕获电网的稳态偏差，并成为一个准确的降阶模型的电网作为网络连接的增长。仿真研究与实际相关的数据，包括验证理论，并进一步说明网络结构和参数对同步的影响。我们的分析给出了具有实际意义的结论，有时挑战了该领域的传统智慧。
The issue of synchronization in the power grid is receiving renewed attention, as new energy sources with different dynamics enter the picture. Global metrics have been proposed to evaluate performance and calculated under highly simplified assumptions. In this article, we extend this approach to more realistic network scenarios and more closely connect it with metrics used in power engineering practice. In particular, our analysis covers networks with generators of heterogeneous ratings and richer dynamic models of machines. Under a suitable proportionality assumption in the parameters, we show that the step response of bus frequencies can be decomposed in two components. The first component is a system-wide frequency that captures the aggregate grid behavior, and the residual component represents the individual bus frequency deviations from the aggregate. Using this decomposition, we define—and compute in closed form—several metrics that capture dynamic behaviors that are of relevance for power engineers. In particular, using the system frequency, we define industry-style metrics (Nadir, RoCoF) that are evaluated through a representative machine. We further use the norm of the residual component to define a synchronization cost that can appropriately quantify interarea oscillations. Finally, we employ robustness analysis tools to evaluate deviations from our proportionality assumption. We show that the system frequency still captures the grid steady-state deviation, and becomes an accurate reduced-order model of the grid as the network connectivity grows. Simulation studies with practically relevant data are included to validate the theory and further illustrate the impact of network structure and parameters on synchronization. Our analysis gives conclusions of practical interest, sometimes challenging the conventional wisdom in the field.