Steam turbine control issue
Steam turbine control issue
(OP)
On site , a CCPP with a steam turbine Franco Tossi Mechanica and Siemens ORSI IT control system we experience lateley the following event: WHile ST runs her start up sequence the speed is controlled by HP Stop (throttle) valve). After the spped of 2800 rpm the conmtrol of spped goes to HP Control valve (governor)> But for some reaosn at the stage of 2990 rpm the speed of ST decreases to 2900 rpm becasue the control goes back to the HP stop valve. This happens one or two times and then the unit sunchronizes OK. Can you share any experience on this issue?





RE: Steam turbine control issue
the problem was that the circuit could not determine if the transfer was from "SV high transfer" to CVs or the "CVs low transferr" back to SVs.
Thus I would look for position logic as the problem