Draining HP Oil

A

Thread Starter

ABDI

Hi,

If the GTG frame 9E mark V was trip with the leakage of HP oil from the GCV, because the gas detector of gas valve cabin , detect and trip the GTG. before the cooldown complete we decide to drain of the hp oil @ 120 rpm to work with the GCV to remove the leakage of the oil from the GCV.

Please say to me how can to drain of the HP OIL from the HP OIL mechanical PUMP?

THANK YOU
 
Hi,

If GTG working at trip sequence and speed of shaft is 120 RPM, Can we do drain the HP OIL at this sequence?

If we do that, what happen for IGV system?

I think may be close the IGV and the air can't coming and the temperature can't reduce in the other equipments system?

Is true or Not?

THANK YOU
 
ABDI,

When a GE-design Frame 9E heavy duty gas turbine (with or without DLN-I combustors) at 120 RPM on cooldown sequence after a trip from load, the IGV reference is 34 DGA (DeGrees Angle). To verify this, look at the IGV Display on the HMI and note that the reference value (the "setpoint") is 34.0 DGA, and the actual value should likely be something less than 34.0 DGA.

There are mechanical stops to prevent the IGVs from closing to less than approximately 32.0 DGA.

If by "HP oil" you mean Hydraulic Oil (yes; it's Lubricating Oil at a high pressure), you need to look at the Hydraulic Oil P&ID. You should find that there is a shaft-driven hydraulic pump (which will be turning, albeit slowly) if the turbine is at 120 RPM and producing some pressure. You should also see that there is one or two hydraulic accumulators. There are two valves per hydraulic accumulator: a "block" valve and a "bleed" valve. The block valve should always be open under normal operating conditions (it should never be closed except during unusual conditions or during maintenance), and usually has the larger of the two handles (per accumulator). The bleed valve (usually the smaller of the two handles) should always be closed during normal operation.

The ONLY way to reduce/eliminate hydraulic pressure is to fully open the bleed valves of the hydraulic accumulator--if there are two, then you need to open both of the bleed valves. This will allow the hydraulic pressure to drain to the L.O. tank with no backpressure, and this should cause the hydraulic pressure to go to <b>NEAR</b> zero.

THERE WILL, HOWEVER, BE SOME PRESSURE/FLOW IN THE SYSTEM IF THE TURBINE SHAFT IS SPINNING AND THERE IS AN ACCESSORY GEAR-DRIVEN MAIN HYDRAULIC PUMP. SO IF YOU "OPEN" A TUBING FITTING SOMEWHERE IN THE HYDRAULIC SYSTEM BE PREPARED FOR SOME FLOW/PRESSURE IF THE SHAFT IS SPINNING AT 120 RPM.

<b>Many people have opened the hydraulic accumulator bleed valves to reduce/eliminate hydraulic oil pressure during some off-line maintenance activity or troubleshooting, and then forgotten to close them prior to starting the turbine. It is not possible to open the fuel stop valve and get fuel into the turbine during firing if there is no hydraulic pressure or insufficient hydraulic pressure.</b>

Please write back to let us know how you fare.
 
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