Improvements in steam temperature control on a modern oil-fired power-station boiler

Improvements in control strategy for steam temperature have been made at Fawley power station because of the changing emphasis, from base-load to load-following, and to two-shift operation. Saturation protection is included to prevent tube waterlogging; although the principle is well established, the implementation is superior to some others. A new valve characteristic is recommended, although, as a temporary expedient, gain adaption has been used to emulate the desired characteristic. Finally, the slow dynamics of the final temperature control are countered by a predictive calculation, backed up by a feedback trim. Experimental results are presented, and a suggestion is made for a further improvement in the predictive calculation, suitable for a digital implementation.