Model Identification of Reheated Steam Temperature in 600MW Ultra-supercritical Unit

Ultra-Supercritical (USC) unit is more and more popular in coal-fired power industry. The reheated steam desuperheating system exerts great influence on the USC unit´s economy and safety in power plant. In this paper, multi-variables reheated steam desuperheating system of USC unit is constructed and then closed-loop identification method based on Subspace model identification (SMI) is used for model identification of reheated steam desuperheating system. Closed-loop SMI is applied to build the unit step response model directly. From practical experience of engineers, the model can reflect the dynamic and steady characteristics of superheated steam system well.