I Need to understand the various tripping points of gas turbine with respect to following points -

1. Trip point protects what?
2. what can be damaged if trip function failed to trip the machine?

trip points are
a. High exhaust pressure (63ET,63EA)
b. Low trip oil pressure (63HG-1,2,3)
c. Inlet air pressure high (63TF-1,2)
d. Low lube oil pressure (63QT-1,2)

which points are clear to me, i haven't asked.

One example for what i want here.
d. High lube oil temperature (26QT-1A,1B)

Ans :
1. (Trip point protects what?) It protects all bearing, LGB and AGB from high temperature.

2. (what can be damaged if trip function failed to trip the machine?) LGB and AGB and bearings will be damaged in absence of proper cooling.

Hope my question is clear.

 

Your question is NOT clear, at least not to me.

The "turbine" is being protected at all times.

a. Try exhaling through a mask. Try exhaling through three or five masks. It's not easy, and it restricts air flow through your lungs. Same goes for a combustion turbine. Restricting the air flow because of high back pressure will limit the power output and cause higher-than-normal internal temperatures.

b. Low trip oil pressure. If there's not enough trip oil pressure to keep the stop valves open, then it's likely the control system can't control the fuel flow. Uncontrolled fuel flow can cause bad things to happen.

c. It's not high inlet air pressure that's the problem; it's a high differential pressure across the inlet air filters. Try inhaling through a mask. Try inhaling through three masks, or through a dirty mask. Ain't so easy, is it? If the differential across the inlet air filters/inlet system is high, it may cause the inlet air filters to rupture which may cause a lot of dirt from the filters to enter the axial compressor, or unfiltered air from entering the axial compressor. Neither of which is good for the machine.

d. Low L.O. pressure. Sorry; but that one's obvious.

When the temperature of L.O. is high enough, the vapors can be easily ignited (vapor temperature). If that happens there can be a fire in the bearing enclosures, which ain't good for any thing or any one.

It's not that high L.O. temperature by itself can damage the Accessory Gear Box or the Load Gear Box bearings, it's more that the vapors can be ignited and cause major damage to the unit in areas that aren't normally protected by fire extinguishing agents (CO2; Halon; etc.).

Hope this helps! These kinds of questions are more appropriate for a consultant than this kind of forum. If you need more specific information for any other alarms, seek the counsel and wisdom of a knowledgeable consultant if you can't work through the possible damage yourself.

 

On item b., low trip oil pressure. The main purpose of this is to trip the electronic control in the event of a mechanical trip - either mechanical overspeed bolt or the manual trip lever.

Basically, while any of the trips in the Speedtronic control will dump the trip oil, the "low trip oil pressure" pressure switches only trip the electronics after a mechanical trip has occurred. The alarm is inhibited when the trip oil is dumped by one of the trip solenoids. Then you get an alarm from whatever protective system caused the trip solenoid to dump the trip oil.