Hello,
In regards to a GE heavy duty steam turbine with Speed-Tronic; MK6e controls. There is a 'Turbine Trip' button on the front standard of turbine and there is a 'Turbine Trip' button in the control room (a dual button set-up requiring pushing of 2 buttons at same time). Question is, why does the turbine trip differently when pressing the button on the front standard? Shouldn't it trip the same way from each location? When tripping from the front standard, it does not energize the 86ET relay. When tripping from the control room it does energize the 86ET Relay. Is this normal?

 

@BobtheBuidler,

Was the Mark VIe provided with the steam turbine when it was originally installed and commissioned or was it an upgrade from an older version of a GE steam turbine control system? If so, it’s sometimes realized later that the configuration of the Mark* VIe had an odd function that wasn’t caught by the field service person commissioning the machine (on steam turbines and gas turbines).

I don’t have a lot of experience with steam turbines, and I don’t recall working on a steam turbine with an 86ET device—which I presume is some kind of lockout relay that must be manually reset when activated/energized and which may prevent a re-start unless it is
manually reset. That wasn’t uncommon on older hydraulic turbine control systems, and may not have been considered during the factory programming/configuration of the Mark* VIe replacing the older turbine control system.

In any case, this is a very good question for the Mark* VIe supplier.

Please let us know what you find out.

 

The GE turbine/generator was put in service in 1980 with the GE MK3 turbine controls.

 

@BobtheBuidler,

This issue should be communicated to GE (or whomever the packager of the turbine control system upgrade was) for review and comment. The MK3 was an electro-hydraulic turbine control system (with analog circuitry). There was probably some kind of E-stop push-button or device on the turbine front standard for local manual tripping of the turbine. Again, I'm not really familiar with steam turbine control systems, or with an 86ET lock-out mechanism. There was probably some kind of E-stop push-button in the operator control room, also. It would be worth a look at the old Mk3 elementary drawings to see how both devices actually tripped the machine--and if they both actuated the 86ET lock-out mechanism to affect a turbine-generator trip.

But without a lot more detailed information that's about all I can advise. Again, you would be well advised to know how both locations (control room operator console and front standard) affected a turbine-generator trip. If there was some kind of "major" change to the hydraulic control scheme of the turbine this might also have been the cause for the change or even overlooked during the configuration and programming of the Mark* VIe turbine control system. If the Mark* VIe is still under warranty it would be best to involve the Mark* VIe packager (GE or ???) for review, comment and possible reconfiguration/resolution.

 

Thanks for the good info. I am in the process of opening a case file with GE to get this issue resolved. I appreciate your helpful input.

 

@BobtheBuidler,

This issue should be communicated to GE (or whomever the packager of the turbine control system upgrade was) for review and comment. The MK3 was an electro-hydraulic turbine control system (with analog circuitry). There was probably some kind of E-stop push-button or device on the turbine front standard for local manual tripping of the turbine. Again, I'm not really familiar with steam turbine control systems, or with an 86ET lock-out mechanism. There was probably some kind of E-stop push-button in the operator control room, also. It would be worth a look at the old Mk3 elementary drawings to see how both devices actually tripped the machine--and if they both actuated the 86ET lock-out mechanism to affect a turbine-generator trip.

But without a lot more detailed information that's about all I can advise. Again, you would be well advised to know how both locations (control room operator console and front standard) affected a turbine-generator trip. If there was some kind of "major" change to the hydraulic control scheme of the turbine this might also have been the cause for the change or even overlooked during the configuration and programming of the Mark* VIe turbine control system. If the Mark* VIe is still under warranty it would be best to involve the Mark* VIe packager (GE or ???) for review, comment and possible reconfiguration/resolution.

We had a MK3 System GE and converted the Controls to a 3rd Party Foxboro Turbine Controls. There are a Couple Scenarios here not being brought up. The 2 button is a parallel buttons opening up a circuit that goes to a 24 VDC Trip Coil in the EHC System and the Buttons are monitored on a First out Panel. The term ET is telling the Controls that someone ET (Electrically Tripped) Tripped the EHC Sytem on the Machine.
The Front Standard Emergency Trip is also a Monitored button or lever switch switch that Trips the EHC System out. Some MK3 Systems had 2 Trip Coils on the Trip out Solenoid.
Like WTF Stated is the Wiring Book will show you the externals from the ET going to probably the Blowdown Valves opening circuits along with little things like the 86G lockout relay on the Generator. I've been retired for 4 years but I can tell you that the MK3 externals book will show you the Connections. The main ones are ETV, MTV Trip Coils in the EHC Circuit. That ET Button/Lever on the machine is a local for emergency conditions like a Fire the Operator sees or a very abnormal condition. The machine would Slam the valves shut and reverse power would Trip the Generator.
That old MK3 system had a Hit Panel, First out that monitored these conditions. Hopefully these Tidbits will help you out. GE was my Favorite Turbine Controls. I also worked on a GE MKIV Gas Turbine 7EA Controls. Triconex Turbine Controls on Small Steam Turbine and Frame 5 GE Gas Turbines. It was a Good Job and made my Retirement pay. Happy Thanksgiving Holidays to all.