With the integration of new energy, wind, PV aggravate the energy imbalance of the power grid for a period.Traditional thermal power unit have long frequency modulation response delay, low power climbing speed, low stability accuracy and poor frequency modulation performance. And after the unit participates in AGC regulation task, the power generation cost increases and the equipment is worn. Flywheel energy storage has the advantages of millisecond accurate control of charge and discharge, high adjustment precision, fast response speed and bidirectional adjustment. Therefore, it is a very good frequency modulation resource. Combined frequency modulation of thermal power+ energy storage system can effectively improve Kp value and benefit of power plant in practical application.