The capacity allocation of integrated energy system(IES) is one of the important factors affecting system operation stability and economic benefit

and is the key research content in the system planning stage. To explore the best working mode of power-to-gas equipment in the system and the influences of such factors as energy storage equipment

photovoltaic equipment and fan on the system economy

this paper introduces the above equipment into the IES. Then

a mixed integer nonlinear programming model considering the capacity allocation constraints

fivebus equilibrium constraints and energy storage constraints is constructed with economic benefit as the optimization objective. Moreover

a citizen service center in north China is taken as an example to verify the effectiveness of the model

and the six operation schemes are compared. The results show that

the reasonable allocation of power-togas equipment can effectively improve the system economy

which provides a theoretical basis and technical support for the subsequent research on the operation stage of the IES.