Under the background of “dual-carbon” goal

the combined heat and power units with once through boilers are required to have the ability to quickly change load. To address this need

a strategy based on linear time-varying model predictive control(LTV-MPC) for coordinating electricity and heat to change unit load is proposed

which can simultaneously utilize boiler heat storage and heat network heat storage to improve the rate of variable load. Firstly

the deviation of the heat load signal is integrated to establish an equivalent heat load model

which is used as one of the controlled variables in the prediction model. Then

by taking rapid load tracking

stable unit operation

and timely compensation for heating as the objective of MPC rolling optimization

the optimal control law for each moment is solved online

and then it is applied to the unit. In addition

the operational constraints of the unit are explicitly addressed to ensure that changes in the heating extraction flow rate do not affect the operational stability of the low-pressure cylinder. Finally

simulation verification is conducted on a 350 MW unit

and the results show that this strategy can accurately track the 5%Pe/min variable load command. Furthermore

the heat load recovery time is reduced by 26% compared with that of the electric heating coordinated variable load strategy based on PID. The simulation results have verified the superiority of the proposed strategy in improving the fast load changing capacity of heating units.