Small signal strength analysis tools for IBR-dominated power systems using impedance-based modelling

As part of the global decarbonisation efforts, renewable energy resources are increasingly replacing fossil-fuel-powered synchronous generators. These resources are connected to the power system through power electronic inverters. While inverter-based resources (IBR) offer high flexibility through their control algorithms, they also introduce new challenges, particularly unprecedented oscillatory interactions. Recently, numerous unexpected sub-synchronous oscillation events have been reported worldwide, especially in high-IBR regions, reflecting a significant reduction in system strength. These events highlight the need for new system strength assessment tools capable of capturing IBR interactions.
My PhD research focuses on developing metrics and tools for small-signal strength analysis in IBR-dominated systems, to facilitate greater IBR integration without compromising stability. Small-signal strength is the power system's ability to remain stable upon small perturbations such as operating point or control parameter changes. Traditionally, this is assessed using state-space based techniques, which require full system knowledge, information often unavailable due to IP and confidentiality restrictions from IBR vendors. As an alternative, black box impedance-based models can provide the same information without requiring detailed models.
My work involves developing a suite of tools to enable faster IBR connection processes while preserving system strength. This includes a metric to assess small-signal strength at potential inverter installation locations in the network, an inverter connection screening tool, to rapidly screen a large number of inverter configurations, types and parametrisations based on their potential impact on the system's small-signal stability and protocols and requirements to ensure stable operation of inverters under evolving grid conditions along with tools to assess the stability implications of retiring existing equipment from the network.