# Coordinated Dispatch of Multi-Energy Microgrids and Distribution Network with a Flexible Structure
## 5 Simulation Result
### Result Analysis
#### 5.2.2 Second Level  
Figures 10-12 present the load balance of MGs in Case 1. The MG1 makes full use of the cooling and heating power. There is no cold and heat power curtailment. In the beginning, the electricity price is low and load is light; to consume the energy generated by the renewable power sources, the MG1 tends to purchase electricity from the DN and the MG2, 3 with surplus power, and the GT is in the shutdown state. When the GT is not working, the GB and the EC are used to meet the cooling and heating load demand in the MG1, respectively. As the electricity price and the load increase, the GT begins to generate electricity, and the WH transforms the waste heat from the GT to the steam. AC  
Figure 8: Remote-controlled switches in 24 h.  
Figure 9: Power interaction on tie lines (**a**) Case 1 (**b**) Case 2 (**c**) Case 3.  
and HX absorb the steam to satisfy the cooling and heating load. The GB and the EC supplement insufficient demand. From 12:00 to 18:00, since all the steam transformed by the WH is to meet the demand of the heating load, the cooling load is fully satisfied by the EC. The battery is discharging during the peak electricity price period (9:00-11:00, 19:00-21:00). Similarly, the battery is charging in other periods (4:00-8:00,15:00-18:00), and the maximum charge-discharge power is up to 100 kW. Figure 11: Balance curve of MG2. (**a**) Power balance (**b**) cooling balance. Figure 12: Balance curve of MG3. (**a**) Power balance (**b**) heating balance. Figure 10: Balance curve of MG1. (**a**) Power balance (**b**) cooling balance (**c**) heating balance. In MG2, as can be seen from Figure 12, renewable power sources generate more electricity than the MG needs, so MG2 tends to sell electricity to DN and other MGs with insufficient electricity. The GT only works at the peak electricity price period (9:00-11:00,19:00-23:00) to generate waste heat to meet the cooling load demand while selling excess electricity to DN and other MGs. The rest time period is satisfied by the EC. The power exchange only happens among MGs. The charging and discharging state of ESS is also related to electricity price and load level. MG3 mainly sells electricity to other MGs and DN, and the operating state of GT and ESS (maximum charge-discharge power 100 kW) is similar to that of MG1. The waste heat generated by the GT is supplied to the HX through the WH, and the GT is used for heating when the GT is not working or the HX is unable to meet the heating load. In Case 1, the MGs only consider their own operation object, regardless of the working condition of the DN. It is obvious that the total operating cost of the MGs is the lowest. However, the power loss and voltage offset of the distribution network have not been optimized in this case. Compared with Case 2 and Case 3 in Table 5, the above two values in Case 1 are higher, which is not permitted in the actual situation, since it will worsen the operating status of the DN and increase the failure rate. It is not beneficial to the global optimal operation of the whole system. The goal of Case 2 and Case 3 is to optimize the MGs' dispatch under the consideration of the DN. The MGs should take the power exchange instructions into consideration not just considering their own economic benefits. In this case, although the operation cost of the MGs has increased, the power loss and voltage offset of the DN reduce significantly, which is very effective for the optimization of the whole system. The economic benefits of the MGs also need to be guaranteed, and the increase of the cost should not be too great. The reconfiguration of the DN can optimize the operation of the DN while increasing the operating cost of the microgrids as little as possible and control it within a reasonable range. Table 6 shows the cost of the three MGs in all cases. As can be seen from Table 6, MG2 makes profits while MG1 and MG3 generate cost.