Abstract: In this paper, the advanced coordinated control and reheat steam temperature control strategies based on the generalized predictive control technology are proposed to solve the problems of Units 3 and 4 of Anhui Huainan Pingwei Power Generation Company, such as, the load changing rate is only 1%/min, the fluctuations of the main steam pressure and temperature are above 0.7 MPa and 15 ℃ respectively and the automatic reheat steam temperature control cannot be put into use. The practical application shows that, with the new control strategies, the load changing rate reaches up to more than 1.5%/min; in the process of load change, the maximum dynamic deviations of the main steam pressure and temperature controls are within 0.4 Mpa and 6 ℃ with the related parameters no longer oscillating. This improves the operational stability of the units. Moreover, the effective control of the reheat steam temperature by flue gas baffle is realized with the maximum dynamic deviation to be within 6 ℃ and the reheat spray amount reduced by over 20 t/h, which improves the operational economic efficiency of the units.

Key words: supercritical unit, coordinated control system, reheat steam temperature, generalized predictive control, load regulation performance