Recently

deep peak load regulation of large coal-fired units has become a common phenomenon. During the period of deep peak load regulation

the actual operation conditions of steam turbines and auxiliary equipment are far away from the design conditions

which has a certain influence on the safe operation of the units. Based on the operation of some units in the period of deep peak load regulation

this study analyzes the impacts of deep peak load regulation on the operation of turbines

the lifetime of turbines and auxiliary equipment

and the economical efficiency of the units. And then the common problems and the corresponding treatment measures are summarized. The results show that the large-scale variable load operation decreases the lifetime of the unit

affects the distribution of the unit's overall lifetime

and reduces the actual operational lifetime of the unit. The economical efficiency of the unit is obviously decreased when the unit participates in the deep peak load regulation and operates below the 50% load. During the low-load operation

the economical efficiency indexes of ultra-supercritical units decrease more than that of the sub-critical units. So it is recommended that sub-critical units should be used to undertake the deep peak load regulation as much as possible. During the period of deep peak load regulation

the use of the operation mode of the single steam pump can ensure that the steam pump operates in a high-efficiency range and the economical efficiency is good.