A Semi-Analytical, Heterogeneous Multiscale Method for Simulation of Inverter-Dense Power Grids

在追求低碳、清洁发电的过程中，风能和太阳能等可再生资源在传统上依赖化石燃料发电的电网中变得越来越重要。然而，由于可再生能源的间歇性和多变性，通过电力电子逆变器进行可再生能源的集成给电网规划和运行带来了不确定性。虽然基于电池的储能系统可以缓解可再生能源的影响，但它们也通过电力电子逆变器进行集成。所有这些因素正在将当今的电网塑造成一个逆变器密度高的电网，这对其极其复杂的多时间尺度动态的计算机模拟提出了相当大的挑战，从微秒到几个小时不等。该项目旨在建立一个统一的多时间尺度建模和解决方案框架，以应对这一挑战，并将给电力系统仿真领域带来革命性的变化。该项目的智能优点包括同化异质多尺度方法和半解析解方法，以实现高精度和高效率的模拟。该项目的更广泛影响包括深入了解逆变器密集型电网的动力学，建立高性能的多时间尺度模拟器范例，促进跨学科教育和促进电网脱碳。电力系统仿真是评估扰动下电网稳定性和可靠性的关键。逆变器密集电网的多时间尺度行为可能涉及电磁暂态、机电和准稳态动力学。要准确地模拟这样的系统，需要在较长的时间内以小的时间步长求解大量的非线性和刚性的微分方程组和代数方程。该项目开发的异质多尺度方法将允许特定情况下的模型简化和求解器参数化，以实现在模拟运行时自动放大和缩小宏观和微观时间尺度之间的模拟分辨率。通过半解析求解器，在每个时间尺度上采用变步长和变阶次机制。验证研究将包括实际电网模型中的次同步振荡、暂态稳定性和黑启动场景，基于逆变器的资源渗透率从50%到100%不等。该项目的结果有可能促进高效模拟方法方面的知识，这些方法也适用于其他多时间尺度的联网系统。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

In the pursuit of low-carbon, clean electricity generation, renewable resources such as wind and solar are gaining prominence in a power grid that traditionally relies on fossil fuels to generate electricity. However, the integration of renewables through power electronic inverters introduces uncertainties to grid planning and operations due to their intermittent and variable nature. While battery-based energy storage systems can mitigate the impacts from renewables, they are also integrated through power electronic inverters. All these factors are shaping today’s power grid into an inverter-dense grid, posing a considerable challenge in the computer simulation of its tremendously complex, multi-timescale dynamics, ranging from microseconds to hours. This project aims to establish a unified multi-timescale modeling and solution framework addressing this challenge, and will bring transformative changes to the field of power system simulation. The intellectual merits of the project include assimilating heterogeneous multiscale methods and semi-analytical solution methods for highly accurate and efficient simulations. The broader impacts of the project include an in-depth understanding of the dynamics of inverter-dense grids, the establishment of a high-performance multi-timescale simulator paradigm, the fostering of interdisciplinary education and the facilitation of power grid decarbonization. Power system simulation is crucial for assessing grid stability and reliability under disturbances. The multi-timescale behaviors of an inverter-dense grid may involve electromagnetic transient, electromechanical and quasi-steady-state dynamics. Accurate simulation of such a system requires solving numerous nonlinear and stiff differential and algebraic equations at a small time step over an extended period. The heterogeneous multiscale methods developed by the project will allow case-specific model reduction and solver parameterization to enable automatic zoom-in and -out of the simulation resolution between macroscopic and microscopic timescales on the fly of simulation. Variable-step and -order mechanisms will be employed in each timescale through semi-analytical solvers. The validation studies will encompass sub-synchronous oscillation, transient stability, and black-start scenarios in realistic grid models with a penetration of inverter-based resources ranging from 50% to 100%. The results from the project have the potential to advance knowledge in efficient simulation methodologies, which are also applicable to other multi-timescale networked systems.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.