Based on the fifth generation district heating and cooling (5GDHC) system with deep bidirectional coupling of electric power network, a simulation model of a new electro-thermal bidirectional coupling network with complex new characteristics was constructed. Considering that the coupling nodes and coupling modes of the new interconnection network had changed, which could lead to security issues in the operation stage, the multi-time-scale analysis method was introduced to divide the quasi-steady-state stages of the electro-thermal network. The interaction mechanism between the 5GDHC system and the electric power network was explored by adding disturbances in different quasi-steady-state stages, and the differences in interaction behaviors between it and the traditional electro-thermal network were analyzed. Finally, the validity of the model and quasi-steady-state analysis was verified through the integrated energy system of a 12-node distribution network and a 26-node heating network in a certain area. The simulation results show that the complementary cold and heat power of the network can reach 13.5 MW in the time domain, the heat loss under low temperature operation only accounts for 1.3% of the network heat supply, and the number of hydraulic junction points reflecting the hydraulic characteristics of the network is increased to a maximum of 5. The quasi-steady-state analysis reveals that compared with the traditional electro-thermal network, the hydraulic change of the new electro-thermal network is more significant, reaching 5.7 kg/s, while the thermal change is relatively gentle, only 0.054 ℃. In addition, the disturbance does not affect the indoor temperature of the building.