Contribution to power oscillations damping of inverter based resources

This paper presents a Power Oscillation Damping (POD) controller, inspired by traditional Power System Stabilizer (PSS), as an additional control loop for Inverter Based Resources (IBRs) controlled in grid following (GFL) mode. The major idea is the contribution of several IBRs to damp electromechanical oscillations of the power system, in order to increase the power system hosting capacity. During frequency transients, the POD modifies the reactive power reference of the GFL control. The POD has the frequency measurement as input signal, and its tuning is based on the root locus design technique. This technique relies on the modal analysis, so the damping contribution is assessed through small signal stability metrics. The test case power system is a modified version of the Western System Coordinating Council (WSCC) 9-bus benchmark, which has been analysed using the DIgSILENT PowerFactory software. The results show that the proposed controller damps the electromechanical oscillatory mode in a similar way to the PSS, increasing the hosting capacity of renewables in terms of small-signal stability.