Wide-area measurement signal-based stabiliser for large-scale photovoltaic plants with high variability and uncertainty

In this study, norm bounded linear quadratic Gaussian controller synthesis method is utilised to design a wide-area measurement signal (WAMS)-based power oscillation damping controller at photovoltaics (PV) plants. The uncertainties associated with the system are confined by the system matrices which are the affine functions of parameters belong to a convex polytopic region. A hybrid method based on Hankel singular value (HSV) and right-half-plane zeros (RHP-zeros) is utilised to assess and select the optimal feedback signal for the PV wide-area damping controller. First, the HSVs of the delayed subsystems are employed to preselect the candidate signals for damping the target mode. Then, the RHP-zeros and the modal interaction measures of the candidate signals are evaluated. Finally, the signal with minimum variance in HSV and modal interaction over the wide range of operating conditions is selected as the optimal feedback signal for the controller design. The wide range of operating conditions is obtained by the probabilistic distribution of loads, synchronous generators and PVs. The approach has been tested on a large 16 machine, 68 bus test system as compared to geometric measures of controllability/observability method and has shown improved performance.