Abstract：The integrated energy system contains adjustable resources and flexible operating modes，which to a

certain extent play a supporting role in the power grid and assist in optimizing its operation. Based on this，an

optimal operation model of integrated energy system considering support capacity to power grid was proposed.

Firstly，the electric-heat integrated energy system（EHIES）was considered as the research object and the EHIES

model was established. Secondly，considering the expected support demand of external power grid and aiming at

meeting the expected support demand of external power grid，the optimal operation model of EHIES was

established. Considering the complexity of the model，the Bacterial Colony Chemotaxis optimization algorithm was

used to solve it. Finally，an integrated energy system in northern China was considered as an example and the

effectiveness of the proposed model was verified. By adjusting the flexible operation of the EHIES，it can

effectively meet the expected support needs of the external power grid and play an external support role.

      Key words：integrated energy system（IES）；support to power grid；adjustable resources；optimal operation