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In view of the requirement of wet state control for feed water system of thermal power unit with boiler circulating pump， the water level control of water storage tank， wet state feed water flow control and dry and wet state conversion are studied， and an autonomous object-oriented wet-state full-range control method for feed water system of thermal power units is proposed. An object-oriented control strategy was designed for the outlet control valve of boiler circulating pump， feed water bypass control valve and steam turbine-driven feed water pump， which can switch adaptively and run synchronously in parallel under different operating conditions.Based on the operation state and parameter self-planning control mode of feed water control equipment. The application results show that the actual operation process shows that the designed wet feed water automation control strategy can meet the needs of wet feed water system. The relevant parameters and operation curves of wet feed water control system put into operation can provide reference for logic optimization and operation debugging of wet feed water control of the same type units with boiler circulating pump.

In view of the insufficient primary frequency control of a 1050 MW ultra-supercritical unit equipped with No.0 high-pressure heater and overload valve under some working conditions， the primary frequency control function of the unit is analyzed and studied. A new mode of the primary frequency control based on overload valve under different load conditions is designed， which redistributes the flow command of the DEH（digital electro-hydraulic control system） high-pressure regulating valve and overload valve according to the power grid frequency action interval. Through the primary frequency control test under different load sections and different frequency difference conditions， the active range of the overload valve is obtained， and the conditions such as speed governing droop， turbine vibration and extraction temperature of No. 0 high-pressure heater are constrained to ensure the stable working condition of the unit during the overload valve participating in primary frequency control. At the same time， through the comparison of the actual load， DEH total flow command， high-pressure regulating valve opening and other parameters under various working conditions， the problem of the integral saturation of the DEH load controller is proposed and optimized to guarantee the performance of primary frequency control of units.