## 1 Introduction
analyzed the economy of wind power consumption under the condition of large proportion of wind power penetration and established a coordinated optimal dispatching model of integrated energy system considering power to gas (P2G) technology [20]. [PERSON] et al. studied the joint planning problem of grid and natural gas network by ADMM technology [21]. [PERSON] et al. established an optimal dispatching model for integrated natural gas network and grid in order to improve consumption capacity of clean energy [22]. The above references respectively establish power flow or dispatching model for a single device unit or coupling device unit in EGCS, and formulate corresponding optimal operation strategies through some technical methods, but all of these references do not effectively evaluate the dispatchability of EGCS. With the increasing capacity of wind, solar energy, and other DG connected to the power system, EGCS's power generation and grid connection technology have become the hot issues concerned by the majority of power science and technology workers at present. Wind and solar energy have uncertainties such as stochastic fluctuation, intermittence, and conversion between different energy sources in the process of power generation, which makes the dispatching of EGCS more complicated, and even directly affects the dispatchability capacity and dispatchability requirement of the system during the dispatching time. Neglect of uncertainties in DG and load in the EGCS, and energy conversion losses, may lead to security and stability problems. Therefore, the establishment of a joint optimal dispatching model between grid and other DG has become a study hotspot. [PERSON] et al. proposed a joint optimal dispatching scheme of energy and reserve based on microgrid combined cool, heat, and electric supply. Supported by the theory that heat supply has thermal inertia, the scheme considers that the reserve capacity of grid can be improved by the mutual conversion of different energy sources, and the conclusion is validated according to the actual data of Chicago Industrial Park in the United States [23]; [PERSON] et al. 's study was based on the optimization of the current status of gas-heat power joint dispatching in residential quarters, and concluded that the optimization strategy has the characteristics of strong pertinence, multi-selectivity, and feedback interactivity [24]; [PERSON] et al. simulated and analyzed the joint dispatching strategy considering demand response, and the simulation results show that this kind of dispatching strategy can greatly improve the efficiency of distributed energy utilization and reduce the operation cost of power system [25; 26; 27]. Therefore, the connectivity of DG and the grid has become the main trend of energy structure. However, EGCS has different coupling modes, and with the rapid development of the Energy internet, the access of a large number of DG and active loads increases the overall complexity of the system. The above references evaluate or optimize the uncertainties of the system due to the integration of new energy sources or active loads. However, there is no qualitative or quantitative analysis of the EGCS dispatchability with DG. There are currently no uniform indexes for EGCS dispatchability description. EGCS is more complicated than traditional grid or natural gas network, so the dispatching model of a single network needs to be improved to apply to the economic dispatching of EGCS. In addition, to accurately evaluate the dynamic characteristics of the system under the circumstance that consider the uncertainty of the system, it is necessary to quantify the dispatchability of energy and demand in the network, so as to formulate a more realistic dispatching operation strategy. For this purpose, this paper proposes an EGCS operation strategy study model considering dispatchability to correctly evaluate the dynamic characteristics of energy or load in the system, and makes qualitative analysis and quantitative calculation of dispatchability.