The integration of an additional regenerative turbine is an effective method to decrease the irreversibility of regenerative heaters for ultra-supercritical coal-fired power plants. However, the regenerative turbine belongs to the backpressure turbine and its steam pressure is influenced greatly by the steam mass flow. The purpose of this study is to investigate the dynamic characteristics of regenerative turbine system. Dynamic models were developed and the turbine power and heat consumption rate were calculated during processes of loading down and regenerative heater shutting down. The results indicated that the heat storage in the metal and working medium leads to the delay of the load and the delay increases more at the load-down rate 4%TMCR min−1 compared to 2%TMCR min−1. The load increases greatly in the moment that the regenerative heater shuts down . The respond speed of the high-pressure heater shutting down decreases obviously compared to that of the low-pressure heater shutting down. Moreover, the energy efficiency reduces ultimately with the regenerative heater shutting down.
Keywords ultra-supercritical unit, regenerative turbine, heat storage, dynamic characteristics