Modelling a grid-connected SOFC power plant into power systems for small-signal stability analysis and control

This paper presents a systematic procedure to establish mathematical models of a solid oxide fuel cell (SOFC) power plant integrated in a multi-machine power system for power system small-signal stability analysis and control. First, the paper describes comprehensively how a grid-connected SOFC power plant can be modeled into a multi-machine power system. The model established can be used for power system small-signal stability analysis. Second, a localized model of the grid-connected SOFC power plant is proposed. This localized model can be used for the design of a power system stabilizer attached to the SOFC power plant to improve power system small-signal stability. The design proposed is simple because establishment of the localized model does not need to obtain and validate the information of the entire multi-machine power system. In the paper, an example four-machine power system integrated with a SOFC power plant is presented. The example demonstrates the effectiveness of the stabilizer designed by the proposed method based on the localized model, which is confirmed by the modal computation and non-linear simulation.