Has anybody here experience in conducting actual overspeed trip test for GE Frame 9 GT in Single Shaft?

Would like to know the step-by-step procedure required...

 

Yes; lots of people here have experience with Frame 9E overspeed testing.

What is your specific question (or questions)?

What kind of turbine control system do you have?

Do you want to perform an overspeed test on a running turbine?

Does your unit have a mechanical overspeed bolt that you want to test (can only be done with a running unit)?

Do you want to test the electrical overspeed trip(s), and if so, do you want to do it with the unit running or with a frequency generator?

Does your turbine control system have a display for performing overspeed tests?

You need to provide more information and be specific about your unit and what you want to do and how you want to do it.

And then people with experience can be more helpful and provide a concise response.

 

Ensure that GT TCC 415 V MCC is not fed from its own UAT (Unit Auxiliary Transformers).

If the Turbine is on load reduce the load to around 2MW and open the Generator Circuit Breaker manually from local GCP panel.

If machine has started from turning gear then wait for at least 30 minutes at FSNL.

Once the Generator Circuit Breaker is open, Gas turbine will come to FSNL mode. Ensure that all operating parameters are within limits and the Gas Turbine operating Speed is 100.3% +/- 0.1%.

Open the Excitation field breaker from local GCP panel to avoid over fluxing of generator.

Login to the HMI in Maintenance mode and select Local control location.

Start View2 data collection file to record and analyse important parameters related to overspeed trip and protection system.

From the Control Constant adjust screen in HMI select constant TNKHOS. This constant shall normally be at a value of 110%.
Using the soft buttons on control constant adjust screen reduce the value of TNKHOS to 102% in steps of 1%.

Caution: Care should be taken while changing the constant and its ramp rate to prevent any undesired trips.

Interlock bypass register must be duly filled and approved for this change.

Using the Speed Raise button on the local HMI increase the turbine speed.

Once the speed crosses 102% Turbine should trip on over speed protection and “ ELECRTICAL OVERSPEED TRIP - HP” Alarm should appear on the HMI alarm window as well as in DCS.

Record the actual speed at which turbine trip occurred.

Take an image of overspeed test screen or unit control screen to capture maximum speed achieved and alarm generated.

Take an image of Alarm screen.

Verify that the fuel shutoff valves are in closed condition.

Select COOLDOWN mode from unit control screen.

Using the soft buttons on control constant adjust screen, change the value of TNKHOS back to original set point 110% in steps of 1%.

Interlock bypass register must be duly filled and updated for this change.

Run constchk command from HMI to ensure THKHOS constant value in EEPROM, RAM and AP1 file in HMI is same.

Collect Trip History data in HMI.

Initiate Master Reset from Unit Control screen in HMI.

Logoff from Maintenance mode and login as OPER user in HMI.

Select Remote control location from Unit Control screen in HMI.

Collect Tele diagnostic D1 data in Telediagnostic computer, before lapse of 3 hours. D1 data file retains last 3 hours data history only.

End of the procedure.

 

It's very encouraging to see that people can copy-and-paste.

This procedure is site-specific, <b>AND</b> it is only for the primary electrical overspeed function.

It also presumes the Speedtronic panel is a Mark V with a later-generation GE Mark V HMI.

<b>AND</b> the responder didn't make any distinction about which overspeed this procedure is for.

Further, it lowers the Primary Electrical Overspeed limit--which in and of itself isn't a problem if one is just testing the ability of the Speedtronic to trip the unit on an overspeed condition.

But most insurance companies want to know that Speedtronic will work properly when it should. And, they want to know that all electronic/electrical overspeeds and the mechanical overspeed (if so equipped) work at the design parameters.

To all who read and use this procedure, please understand what it is, and what it isn't. And read and understand this procedure in the context of the unit at your particular site and how it is to be tested or needs to be tested.