# Coordinated Dispatch of Multi-Energy Microgrids and Distribution Network with a Flexible Structure
## 1 Introduction  
With the gradual depletion of traditional primary energy, various forms of renewable energy have been widely used [1]. As the penetration rate of renewable energy gradually increases, the distribution networks (DNs) transform into active networks, the characteristics of which are that control and dispatch are distributed, power flows are bidirectional [2]. Microgrids (MGs) are presented to connect to DNs in response to the growing power supply security issues, as well as considering the economics of energy, cleanliness and various ancillary services [3, 4]. With the maturity of distributed power sources and energy storage technology, multi-MGs' access to distribution networks gradually become the mainstream. As a controllable integrated unit of distributed power supply, energy storage device and user load, the MG can be flexibly controlled and managed and can run in grid-connected or island mode. It is of considerable significance to increase the economic and environmental benefits of the power system. The traditional research of MGs mainly concentrates on the utilization of electric power. With the introduction of the concept of energy internet and the development of communication technology, the barriers between various forms of energy are being broken [5, 6]. The multi-energy systems integratemultiple types of energy, such as natural gas, coal, petroleum, and renewable power sources, which are highly coupled with production, transmission, and management. Combined cooling, heating and power (CCHP) technology is widely used in small and medium-sized MGs, which leads to new challenges for optimized dispatch of MGs [7; 8; 9; 10]. Much effort has been focused on the optimal dispatch of the MGs [11; 12; 13; 14; 15; 16; 17; 18; 19; 20]. [PERSON] proposes a general modeling method using an energy bus to describe the injection of different forms of energy in [12]. To minimize fuel costs, [PERSON] uses the direct search method to tackle the economic problem considering load and DG constraints [11]. [PERSON] develops a mixed-integer linear programming (MILP) dispatch model of MGs considering the lifetime of the battery under the weighted Wh throughput method [13]. For multi-energy microgrids, operating modes proceed following the electric load (FEL), following the thermal load (FTL) and optimal economic dispatch, etc. [14]. [PERSON] proposes an economic dispatch method of CCHP-based multi-microgrids considering the power interaction [15]. [PERSON] proposes an energy sharing strategy, which let CHP units to break the limit of working modes [16]. [PERSON] develops an internal trading method with barter trading, which can reduce the power trading with the external system [17]. For stochastic operation [18; 19; 20], [PERSON] proposes a low carbon micro integrated electric power, natural gas, and heat delivery system, considering uncertainties of renewable power and demand under the scenario-based method in [18]. A hierarchical energy management strategy is presented in [19] to establish an efficient framework for MGs considering the uncertainty of power interaction among MGs. In [20], a joint-dispatch method of reserve and energy is presented for the study of CCHP MGs considering the thermal dynamics of buildings and forecast errors of renewable power. When considering demand response [21; 22], [PERSON] establishes an energy hub with multi-energy flow considering uncertainties of renewable power and different degrees of demand response of cooling and electric load to maximize income in [21]. In [22], a mechanism of bi-transaction mode between CCHP-based-MG and a load aggregator including pricing strategy and a two-stage optimization model is introduced to achieve integrated demand response. As renewable power sources, MGs, distributed energy storage systems, and controllable loads are connected to the DN, power quality monitoring [23] and optimal dispatch [24] of the DN has become increasingly important. There are also many types of research on the coordinate dispatch of the DN and MGs [25; 26; 27; 28; 29].