摘要
电力系统第三道防线中的低周减载是电网在遭受扰动后阻止系统频率快速持续下滑并最终维持系统频率稳定的重要措施之一。与此同时,大量清洁能源接入电网后,使得电网系统频率的特性变得更为恶化。如何在高占比清洁能源下探讨低周减载的优化配置方案是当前亟待解决的关键课题。为此,本文在大规模清洁能源接入电网的背景下,考虑因电源故障导致系统频率下降的情况,推导了能够有效实现减载的关联度指标,并在此基础上提出了一种基于关联度的电网低周减载优化配置策略。其中,利用改进场景分析方法来描述清洁能源的不确定性。进一步,提出了基于调节功率和稳态频率的低周减载方案整定流程。最后,以IEEE标准算例系统为例,通过仿真对比分析验证了所提出的电网低周减载优化配置策略的有效性。
The under-frequency load shedding (UFLS) in the third line of defense of power system is one of the significant measures to prevent the rapid and continuous decline of the system frequency and ultimately maintain the stability of system frequency after disturbance. Meanwhile, when a large amount of clean energy is connected to the power grid, the frequency characteristics of the power system become worse. How to explore and exploit the optimal configuration strategy of UFLS under high penetration level of clean energy is a key issue to be solved urgently. Therefore, under the background of large-scale grid-connected clean energy, this paper deduces the correlation degree index which can effectively realize load shedding. On this basis, the improved scenario-based method is utilized to describe the uncertainty of clean energy. Further, the setting process of UFLS solution based on the adjustment power and steady-state frequency is proposed. Finally, taking the IEEE standard test system as an example, the validity of the proposed optimal configuration strategy of UFLS is verified by simulations and comparative analysis.
