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越来越重要。然而，由于可再生能源的间歇性和可变性，通过电力电子逆变器整合可再生能源给电网规划和运营带来了不确定性。虽然基于电池的储能系统可以减轻可再生能源的影响，但它们也通过电力电子逆变器集成。所有这些因素正在将今天的电网塑造成一个逆变器密集的电网，这对计算机模拟其极其复杂的多时间尺度动态（从微秒到小时）提出了相当大的挑战。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来应对这一挑战，并将为电力系统仿真领域带来革命性的变化。该项目的智力优势包括吸收异质多尺度方法和半解析解方法，以实现高精度和高效的模拟。该项目的广泛影响包括深入了解逆变密集电网的动态，建立高性能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电网在干扰下稳定性和可靠性的重要手段。逆变密集电网的多时间尺度行为涉及电磁暂态、机电和准稳态动力学。这种系统的精确模拟需要在很长一段时间内以很小的时间步长求解大量的非线性和刚性微分方程和代数方程。该项目开发的异构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，以便在模拟过程中自动放大和缩小宏观和微观时间尺度之间的模拟分辨率。通过半解析解，将在每个时间尺度上采用变步和阶机制。验证研究将包括实际电网模型中的亚同步振荡、瞬态稳定性和黑启动场景，其中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推进有效模拟方法的知识，这也适用于其他多时间尺度网络系统。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值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.