In order to eliminate the feed-water flow fluctuation caused by mismatch of the output of feed-water pump and that of the hydraulic coupler in feed-water control of the coordinated control system

for a 2×660 MW supercritical unit of the first phase of Xuangang Power Plant

the feed-water control strategy based on fuzzy self-adaptive PID was put forward

that is

building relationships between three regulation parameters namely Kp

Ki and Kd of the PID and the flow deviation e of the feed-water and its varying rate Δe by using fuzzy reasoning

and then adjusting Kp

Ki and Kd according to different e's and Δe's.Results show that

regulation system of the improved feed-water control system has good dynamic

static characteristic and robustness

the feed-water flow is stable.Therefore

the modified system can satisfy the requirement of unit load variation.