Hello
I am looking for some information on GE Gas Turbine (Model MS9001E DLN) Safety System, in particular how the "Gas Turbine Exhaust Purging" function works. We have a GE safety document which suggests that this function monitors the GT speed during pre-ignition phase. If the speed threshold is not maintained, then the system resets the purge time counter and the purging phase is repeated. I understand all that. However, it also states that if the purge sequence fails because a dangerous condition is detected by the speed sensors then the purge sequence is aborted and restarted. And, in case of a trip, the safety PLC activates the trip sequence of the machine by closing the speed ratio valve and the gas control valves.
My questions are:
1) what is the purpose of this trip considering there would be no fuel gas present during pre-ignition phase?
2) what dangerous condition could be present during purging that would require initiating a trip?
3) how is speed signal used in implementing this trip, i.e. is it low speed trip or a high speed trip or a rate of change trip?
Is there more detailed explanation available of start-up sequences of Mark VI safety system, as the GE documentation seems very primitive.
I am looking for some information on GE Gas Turbine (Model MS9001E DLN) Safety System, in particular how the "Gas Turbine Exhaust Purging" function works. We have a GE safety document which suggests that this function monitors the GT speed during pre-ignition phase. If the speed threshold is not maintained, then the system resets the purge time counter and the purging phase is repeated. I understand all that. However, it also states that if the purge sequence fails because a dangerous condition is detected by the speed sensors then the purge sequence is aborted and restarted. And, in case of a trip, the safety PLC activates the trip sequence of the machine by closing the speed ratio valve and the gas control valves.
My questions are:
1) what is the purpose of this trip considering there would be no fuel gas present during pre-ignition phase?
2) what dangerous condition could be present during purging that would require initiating a trip?
3) how is speed signal used in implementing this trip, i.e. is it low speed trip or a high speed trip or a rate of change trip?
Is there more detailed explanation available of start-up sequences of Mark VI safety system, as the GE documentation seems very primitive.