A Criterion for Oscillation Source Localization With IBRs Based on Sub-Synchronous Frequency Component of Instantaneous Power

Sub-synchronous oscillation (SSO), triggered by inverter-based resources (IBRs), has become increasingly prevalent. The identification and elimination of oscillation source are recognized as effective approaches to mitigate their impact. Nevertheless, the complexity of IBRs often renders current methods insufficient for locating the oscillation source both accurately and intuitively. To bridge this gap, this paper introduces a novel criterion focused on locating the SSO source in IBRs, utilizing the sub-synchronous frequency component of instantaneous power, termed sub-synchronous power (SSP). The equations for the instantaneous power of grid-following (GFL)-IBR and grid-forming (GFM)-IBR are derived. Following this, the direct current (DC) components, encompassing independent fundamental and sub-synchronous frequency-related elements, are separated using the periodicity of the alternating current (AC) components. Furthermore, the fundamental frequency-related components are filtered out from DC components, employing the amplitude coupling relationship between these components. This step allows for the extraction of the sub-synchronous frequency-related component, i.e. SSP. Finally, the flow direction of SSP is used as a criterion for locating the oscillation source. Case studies conducted on the IEEE 39 and 118-bus systems have demonstrated the effectiveness of this method. Compared with the existing criterion, the proposed method can effectively reduce the risk of misidentifying oscillation sources.