Methodological Framework for Stability Analysis, Control Design and Verification in Hybrid Power Plants

This paper addresses the assessment of voltage and frequency stability in hybrid power plants (HPPs) and how to design, to tune and to verify the control system. Firstly, the benchmark off-grid HPP used in this study is described. Additionally, an overview of the general requirement specifications for the HPP controller is presented. A brief classification of stability phenomena in off-grid HPPs is given and the implications on the required detail of small-signal modeling are explained. Secondly, it is ascertained that the state-space method is most suitable for analysis of voltage and frequency stability and likewise serves as a tool for control design and tuning. The main part of this paper is to propose the model-based design approach as a generic guidance for stability analysis, control design including tuning and verification for HPPs. This methodological framework can be applied for both on-grid and off-grid HPPs, independent of plant topology and power management strategy.