With the increasing adoption of renewable energy and HVDC transmission systems, the power system may experience large power fluctuations due to HVDC faults, potentially causing the rate of change of frequency (RoCoF) or frequency deviation limit to be exceeded during the inertia response phase. The system’s ability to withstand these disturbances primarily depends on the amount of system inertia, making it crucial to accurately estimate the effective inertia. The traditional power system frequency analysis commonly employs the system frequency response (SFR) model based on the center of inertia (COI), which does not account for the spatial differences in frequency, and consequently results in reduced accuracy. To address this issue, this paper proposes a modal analysis-based analytical method (MAAM) for analyzing the system frequency characteristics during the inertia response phase. The proposed method retains the frequency dynamics of all generator rotors in the system and more accurately reflects the spatial variation characteristics of frequency compared to the COI model. This paper also introduces the concept of the effective inertia of the system, along with its calculation method. The proposed method is validated using the IEEE 2-region 4-generator system and New England 68 bus system.

中文翻译：

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基于模态分析的电力系统惯性响应阶段频率估计分析方法

随着可再生能源和高压直流输电系统的日益普及，电力系统可能会因高压直流故障而出现较大的功率波动，从而可能导致惯性响应阶段超过频率变化率（RoCoF）或频率偏差限制。系统承受这些干扰的能力主要取决于系统惯性的大小，因此准确估计有效惯性至关重要。传统的电力系统频率分析通常采用基于惯性中心（COI）的系统频率响应（SFR）模型，该模型没有考虑频率的空间差异，从而导致精度降低。为了解决这个问题，本文提出了一种基于模态分析的分析方法（MAAM），用于分析惯性响应阶段的系统频率特性。该方法保留了系统中所有发电机转子的频率动态，与COI模型相比，更准确地反映了频率的空间变化特征。本文还介绍了系统有效惯量的概念及其计算方法。使用 IEEE 2 区 4 发电机系统和新英格兰 68 总线系统对所提出的方法进行了验证。本文还介绍了系统有效惯量的概念及其计算方法。使用 IEEE 2 区 4 发电机系统和新英格兰 68 总线系统对所提出的方法进行了验证。本文还介绍了系统有效惯量的概念及其计算方法。使用 IEEE 2 区 4 发电机系统和新英格兰 68 总线系统对所提出的方法进行了验证。