Clean energy power generation has randomness and volatility. In order to ensure the safe and stable operation of power grid, it is necessary to improve the flexible regulation ability of power grid, so as to improve the consumption ability of clean energy. This paper studies the relationship among power grid peak shaving margin, multi-source regulation limit and abandoning wind, nuclear and solar. In order to reduce the abandoned wind electricity and photovoltaic electricity, a coordinated dispatching strategy for power grids with multi-source and multi-operating domains is proposed in this paper. This strategy incorporates battery energy storage and electric heat storage control into the AGC control system. The power grid adopts different control strategies in different operation periods, so as to maximize the flexible regulation capacity of power grid. Based on the actual data of 3 typical operating days, this paper gives specific measures for power grid peak shaving in different control domains. The numerical results verify the role of electric heat storage and battery energy storage in improving clean energy consumption. In addition, the actual operation results of this strategy in the power grid for 5 consecutive years show that the wind abandonment rate of the Liaoning power grid has been continuously reduced. The wind abandonment rate has dropped from 13% in 2016 to less than 1% for recent 3 consecutive years. The proposed control strategy has a significant effect on improving the ability of power grid to absorb clean energy.