Thermal power plants are required to improve the rate of regulating the power output for various renewable resources connect to the grid. Regulating the once through boiler load by condensate throttling can utilize the store energy effectively and enhance load response rate of the unit. The condensate throttling cascade control designed in this paper is a boiler-turbine coordinated control system combining with the condensate throttling. The condensate throttling channel can rapidly response the load instruction in initial stage of the regulation and the inner loop can keep the water level of deaerator varying in a safe range. Through regulating the feed coal quantity

the boilerturbine coordinated control channel ensures the static performance of the control system in last stage of the regulation

which includes the condensate flow control and water level control for the deaerator. Taking a 1000 MW unit as the example

the above control strategy was applied to carry out the simulation. Moreover

the IAE

ITAE and AGC indexes were employed to compare the new control strategy with the conventional control strategies. The results show that

this condensate throttling cascade control dramatically enhanced the load rise rate of the unit

and the water level in the deaerator changed little during the whole load regulation process.