Coherency Estimation in Power Systems: A Koopman Operator Approach

Integrating a significant amount of non-synchronous generation into power systems creates new technical challenges for transmission systems. The research and understanding of the impact of the non-synchronous generation through back-to-back Full Rated Converters’ (FRCs) on power system’s coherency is a matter of importance. Coherency behavior under the presence of large inclusion of non-synchronous generation requires more research, in order to understand the forming groups, after a disturbance, when the inertia is decreasing due to the decoupling. This document presents the application of the so-called Koopman Operator for the identification of coherent groups in power systems with the influence of non-synchronous generation. The Koopman Analysis clusters the coherent groups based on the measurements obtained. The visualization of the coherent groups identified allows to observe their dynamic variations according to the penetration level or fault location. The applied method of coherency identification is evaluated in the Nordic test system through gradually increasing integration of non-synchronous generations and different fault scenarios.

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