Research on primary frequency control optimization technology based on overload valve

Abstract

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.

Keywords

• primary frequency control
• overload valve
• integral saturation