Abstract: In this paper， the problem of energy maximization in a short time scale is studied when the integrated energy system is offline. Firstly， an optimal dispatching strategy considering multi-energy flow coordination is proposed to meet the short-term energy demand of important loads under isolated networks. The strategy divides the whole system into wind-solar-storage power generation system and combined cooling and heat supply system. According to the principle of maximizing energy utilization， the output priority of each energy supply device is formulated. On this basis， a coordinated optimal dispatching strategy for multi-energy storage units is formulated for wind-solar-storage power generation system. Each energy storage unit is charged/discharged according to the ratio of dispatchable capacity， and the capacity of each energy storage unit is maximized in a short time. For the combined cooling and heating system， a dynamic setting method of minimum reserved electric power PQ.Lmin for gas engine is developed. The value of PQ.Lmin is dynamically adjusted according to the energy supply situation in different periods， so that the gas engine can always operate in the most efficient status and output the maximum cold/heat/electric energy. Through an example analysis， the proposed strategy can make full use of a variety of energy supply device in a short time， effectively prolong the energy supply time， achieve the maximum utilization of energy in a short time， and verify the effectiveness of the proposed strategy.

Key words: integrated energy system, multi-energy storage units, gas engine, isolated grid, short-term energy supply