The optimized operation of combined power and heat system can effectively improve the power system peak load capacity and wind power accommodation rate. Based on the detailed analysis of the heat network topology and its hydraulic and thermal models

a recursive model of heat network is proposed to account for the heat loss in the return pipe network. The model of coupling elements such as thermoelectric generator and electric boiler are studied

and the power flow model of power and heat system is established. By analyzing the operation mode of the heat network

the forward/backward sweep method for calculating the power flow of the heat network is put forward. The model can be used to deal with multi-branch radiant heat network and its electric boiler and other energy conversion devices. There is no need to solve the heat network hydraulic model

have complex network number and form admittance matrix in the calculation process

thus the proposed model has the characteristics of simple programming and fast calculation. The analysis shows that the heat loss of the return pipe network is large and cannot be neglected

and the reasonable selection of the heat source export parameters can improve the wind power accommodation rate.