Impact of Grid Forming Converters on Power System Stability

包括英国在内的大多数国家都在推动可再生能源（RES）的普及，以减少碳排放和应对气候变化，国家电网的预测显示，到2024年，可再生能源发电量有可能满足电力年需求的60%，高于目前的26%。大多数可再生能源是通过电力电子设备连接的，与传统发电厂相比，它们的动态行为有很大不同。随着我们向电力电子接口单元接近100%渗透的电力系统迈进，目前电力电子接口单元的控制结构已经开始显示出局限性的迹象。为此，提出了一种保证稳定运行的潜在解决方案——网格成形变流器。然而，这种成网变流器在多发电机系统中的动态相互作用尚未得到充分的研究。并网变流器、随网变流器与传统常规电厂之间可能出现新的动态相互作用。该项目旨在开发具有多个并网变流器的大型电力系统模型，并研究动态相互作用及其对系统稳定性的影响。还将调查这些模型所需的详细程度，以充分代表大规模系统研究中此类转换器的动态行为。除了研究工作点周围的线性化模型（电力系统小信号稳定性研究的常用方法）外，该项目还将关注非线性动力学和相应的模型，以确保捕获更复杂的动态相互作用。

Most countries, including the UK, promote the increased penetration of Renewable Energy Sources (RES) to reduce carbon emissions and combat climate change with forecasts from National Grid showing the potential for renewable generation output to meet 60% of annual demand for electrical energy in 2024, up from the present level of 26%. Most RES are interfaced through power electronics and have significantly different dynamic behaviour compared to conventional power plants. Current control structures of power electronic interfaced units already started showing signs of limitations as we move towards power systems with close to 100% penetration of power electronic interfaced units. For this reason, grid forming converters are proposed as a potential solution to ensure stable operation. However, the dynamic interactions of such grid forming converters in a power system with multiple generators has not been yet adequately investigated. Moreover, new dynamic interactions between grid forming converters, grid following converters and tradition conventional power plants might appear. This project will aim at developing large scale power system models with several grid forming converters and investigate dynamic interactions and their impact on system stability. The level of detail needed for such models to adequately represent the dynamic behaviour of such converters for large scale system studies will also be investigated. Apart from investigating linearised models around an operating point, a common approach in power system small signal stability studies, the project will also focus on nonlinear dynamics and consequently models to ensure more complex dynamic interactions are captured.