Photovoltaic systems, one of the major renewable energy systems (RESs), are getting integrated into conventional power grids in large-scale, substituting synchronous generators. However, PV systems lack inertia inherently and cannot provide any reserve power. Consequently, large-scale PV integrated grid faces severe frequency instability problems following a synchronous generator tripping event. Although various kinds of external storage systems are utilized to improve frequency response, they pose substantial economic challenges for grid operators. Deloaded PV systems, on the other hand, can assist in enhancing frequency stability without any external supporting mechanisms. In order to maintain frequency stability with minimal expenditure, an accurate estimation of the deloading percentage of PV systems is required. To this end, this paper proposes a novel methodology of estimating appropriate deloading percentages for PV systems in terms of frequency response parameters, using multiple linear regression analysis (MLRA). Simulations are conducted for different PV penetration levels on modified IEEE 39 bus test system. Additionally, a thorough performance comparison of deloaded PV integrated grid with both battery energy storage system (BESS) and synchronous condenser (SC) installed PV integrated grid is conducted. The findings support the feasibility of our method, allowing for accurate estimation and justifying the deployment of grid-connected deloaded PV systems. Deloaded PV systems also outperform other supporting mechanisms in terms of performance. Moreover, they provide insights on how the required deloading percentage decreases with increasing PV penetration. This paper can be used as a guide for grid designers to ensure that PV systems are properly deloaded to maintain frequency stability in large-scale PV integrated grids.

中文翻译：

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估算可再生综合电网中大型光伏电站频率支持的系统方法

光伏系统是主要的可再生能源系统（RES）之一，正在大规模集成到传统电网中，替代同步发电机。然而，光伏系统本身缺乏惯性，无法提供任何储备电力。因此，大规模光伏并网电网在同步发电机跳闸事件后面临严重的频率不稳定问题。尽管利用各种外部存储系统来提高频率响应，但它们给电网运营商带来了巨大的经济挑战。另一方面，卸载光伏系统可以帮助增强频率稳定性，而无需任何外部支持机制。为了以最小的支出保持频率稳定性，需要准确估计光伏系统的减载百分比。为此，本文提出了一种使用多元线性回归分析（MLRA）根据频率响应参数估算光伏系统适当减载百分比的新方法。在改进的 IEEE 39 总线测试系统上对不同的光伏渗透水平进行了模拟。此外，还对卸载的光伏并网与电池储能系统（BESS）和同步冷凝器（SC）安装的光伏并网进行了全面的性能比较。研究结果支持我们的方法的可行性，可以进行准确的估计并证明并网卸载光伏系统的部署是合理的。卸载光伏系统在性能方面也优于其他支撑机制。此外，它们还提供了有关所需减载百分比如何随着光伏渗透率增加而降低的见解。本文可作为电网设计人员的指南，以确保光伏系统正确卸载，以维持大规模光伏并网电网的频率稳定性。