AN IMPROVED LOGIC FOR ENABLING OPERATION OF SPRAY CONTROL AT LOW STEAM FLOW CONDITION

摘要

A method to regulate steam temperature of a power generating boiler/ turbine by spray water means operable at low flow rate of steam, the method comprising the steps of - a memory element (A) is SET to allow opening of a spray isolation valve at predetermined conditions which includes - issuance of an open command, - absence of a master fuel trip condition, and - at low temperature when a main steam temperature value exceeds 4 degrees of the rated steam temperature, to enable a memory element (B);- the memory element (A) is RESET to allow closing of the spray isolation valve contrary to the said predetermined conditions following reseting of the memory element (B) wherein the memory element (B) is selectively operable to identify modes of operation at low steam flow rate.