Impact of Grid Forming Converters on Power System Stability

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.