Traditional dynamic security assessment faces challenges as power systems are experiencing a transformation to inverter-based-resource (IBR) dominated systems, for which electromagnetic transient (EMT) dynamics have to be considered. However, EMT simulation is time-consuming especially for a large power grid because the mathematical model based on detailed component modeling is highly stiff and needs to be integrated at tiny time steps due to numerical stability. This paper proposes a heterogeneous multiscale method (HMM) to address the simulation of a power system considering EMT dynamics as a multiscale problem. The method aims to accurately simulate the macroscopic dynamics of the system even when EMT dynamics are dominating. By force estimation using a kernel function, the proposed method automatically generates a macro model on the fly of simulation based on the micro model of EMT dynamics. It can flexibly switch between the micro- and macro-models to capture important EMT dynamics during some time intervals while skipping over other time intervals of less interest to achieve a superior simulation speed. The method is illustrated by a case study on a two-machine EMT model to demonstrate its potential for power system simulation.

翻译：传统动态安全评估面临挑战，因为电力系统正经历向逆变器资源主导系统的转型，此类系统必须考虑电磁暂态动力学。然而，电磁暂态仿真耗时严重，尤其对于大型电网而言，这是因为基于详细元件建模的数学模型具有高度刚性，且在数值稳定性约束下需采用极小时间步长进行积分。本文提出一种异质多尺度方法，将包含电磁暂态动力学的电力系统仿真问题视为多尺度问题。该方法旨在精确模拟系统的宏观动态特性，即便在电磁暂态动力学占主导地位时亦然。通过采用核函数的力估计，所提方法能基于电磁暂态微观模型在仿真过程中动态生成宏观模型。该方法可在微观与宏观模型间灵活切换，既能捕获某些时间区间内的重要电磁暂态动态，又能跳过其他兴趣较低的时间区间，从而实现卓越的仿真速度。通过双机电磁暂态模型的案例研究，验证了该方法在电力系统仿真中的潜力。