With the development of new energy power

the operation load of coal-fired generating units continues to decrease. Deep peak shaving of thermal power units has become an important technical problem for flexibility adjustment of coal-fired power plants. The peak load regulation performance indexes at different loads of a supercritical 600 MW air-cooled unit are experimentally analyzed. The results show that

when the unit load was reduced from 50% of the rated load to 40% of the rated load

the absolute electrical efficiency of the unit reduced from 41.31% to 41.16%

and the standard coal consumption for power generation increased from 325.52 g/(kW·h)to 328.77 g/(kW·h). When the unit was deeply adjusted to 30% of the rated load

the absolute electrical efficiency of the unit dropped to 37.84%

and the standard coal consumption for power generation rose to 359.83 g/(kW·h).Comparative analysis indicates that

when the unit was further adjusted downward from 40% load

the efficiency of the unit significantly decreased

the heat consumption rate of the unit increased greatly and the operating thermal economy of the unit significantly reduced. The investigation can provide a reference for the economic operation of the units' deep peak regulation.