we have GE fram 9161, and MARK-IV Control system

GT trip due to following alarms appears.
(i)hydraulic differential pressure hi
(ii)Exhaust over temp. hi
(iii)Exhaust over temp hi trip
(iv)turbine air inlet cubicle trouble.
can someone tell me what are interconnection of above alarms.

 

You need to provide the time-stamps for each of the alarms.

 

CSA,

Are all MARK IV simplex??

 

GTG,

On the contrary; most Mark IV's are (were) TMR.

 

The following alarms are not all causes for trip; in fact, only one is typically a trip--the one with the word "trip" in the text message.

(i) Hydraulic Differential [Pressure] High is usually related to a high hydraulic filter differential pressure, and is not typically a turbine trip condition.

(ii) Exhaust Overtemperature High is typically annunciated when the average exhaust temperature (the average of all the exhaust T/Cs, or at least those used in the control & protection of the turbine) is more than 25 deg F greater than the CPD-biased exhaust temperature control reference

(iii) Exhaust Overtemperature High Trip is most likely the condition that tripped the turbine, and is caused when the average exhaust temperature is more than 40 deg F above the CPD-biased exhaust temperature control reference.

(iv) Turbine Air Inlet Cubicle Trouble is not usually a trip condition, but it could be an automatic shutdown. This alarm could be related to many different things, depending on the type of inlet filter and auxiliaries, but, it's not usually a trip (not <b>usually</b>).

Now as to why the turbine exhaust temperature was above the exhaust temperature control reference, well, we don't have any idea (because the original poster didn't tell us) what was happening to the turbine and its driven device prior to the trip. Was there a lightning strike? Was there a frequency disturbance? Was there a fuel supply issue (instability; low pressure; low flow; high pressure; high flow). Was there a low hydraulic system pressure that caused the Aux. Hydraulic Pump (if present!) to start? We don't know what Diagnostic Alarms were present at the time of the event, or were annunciated during or after the event. We don't know what other Process Alarms were present and in alarm at the time of the event.

There's just not enough information to say what might have happened.

As for the "interconnectedness" of the alarms, well, they might be somewhat related, but we don't have enough information to say for sure. We really don't have any information to speak of; not even the timestamps which were asked for.

 

A slight clarification:

I believe all Mark IV's that were provided with a new gas turbine were triple redundant. Technically, none are "TMR" - true TMR didn't happen until Mark V. (True TMR requires that the R, S and T processors be able to read the I/O from each other; Mark IV R, S & T processors could only read the I/O directly connected to themselves.)

There are many simplex Mark IV's that were provided as upgrades to Mark I and Mark II (and older) units, since the Mark I, Mark II and older units did not have the triple redundant instrumentation needed to support triple redundant control processors.