A 6 500t/d cement production line is equipped with a 132kV/6kV main substation and a 12MW waste heat generator set (WHGS). In the event of an external power grid failure, the WHGS will be operated as an isolated grid power supply. This paper analyzes the issues in the existing power distribution system, including its inability to automatically distinguish and switch the operation mode of grid connection and isolated operation, as well as its lack of self-protection in the event of external power grid failure. We propose a solution to build a coordinated machine-network control system (CMNCS) for "power supply, power grid, and load", and introduces the functional composition and structural components of this system. When the external power grid fails, CMNCS can quickly switch to the appropriate power grid operation mode, automatically implement secondary frequency and voltage regulation control to ensure stable operation of the distribution system.