Deployment of a full-size converter utilised hydropower plant to enhance inter-area oscillation damping

Due to the increasing share of inverter-based renewable energy sources and the increased retrofitting of conventional hydropower plants with power electronics, novel possibilities arise for providing damping power in case of occurring inter-area oscillations in power systems. This paper presents a complete model of a variable-speed hydropower plant (VSHP) in a single-machine infinite bus system. The demonstrated analytical model is applied for small-signal stability analysis that contains all relevant converter dynamics and is verified by an additional non-linear time-domain simulation. The damping controller approach located in the full-size converter (FSC) consists of the classical power system stabilizer with additional phase compensation, to which an appropriate wide-area input signal is fed via a phasor measurement unit device. Subsequently, the FSC-VSHP with additional damping algorithm is examined with respect to the significantly higher damping performance with regard to inter-area modes in a three-machine model.