The Gas Turbine Generator trips after a tripping alarm initiates “Stop from the Generator Control Panel.” Whereas no such command was given to the Mark V. It left us complete blank as we cannot detect the fault from where it initiates. After replacing several cards from Mark V no improvement was shown.

Please let me know where the fault may be. I can provide you the data required to identify the fault.

 

To me it sounds like a current detect problem.
Question #1: does the gen actually shut off? if it dose not/ then something with software

Question #2: can you override mark V and run gen and monitor current out put with loads on it? if current is working fine with loads,
then try it with mark V with loads look for drops in current

 

First thing you need to do is go into ALARM.LST and see where this "stop from the generator control panel" comes from. Then go into the rung display and find out what initiates this signal and take it from there.

If you have more details, trip logs, etc., please post them

 

Please check the emergency push button on the mark V panel. The push button or the related wiring might be the culprit. Failure of the push button could cause the unwanted operation of the switch. Replace the switch or temporary disable it to test it if you do not have new spare. Good luck

 

In the summary you indicated the unit was "...shutdown...."

In the body of the original post you indicated:

>The Gas Turbine Generator trips after a
>tripping alarm initiates 'Stop from the
>Generator Control Panel.'

In GE-speak, a shutdown and a trip are two <b>very</b> different things. A shutdown is an orderly unloading, generator breaker opening (usually on reverse power), and a fired shutdown sequence, finally coasting down to cooldown (ratchet; turning gear; etc.). An example is an operator selecting STOP from load. Some other conditions also can initiate an automatic shutdown, depending on the configuration of the unit.

A trip is an emergency shutdown where the fuel is shut off very quickly, the generator breaker is opened and the unit coasts down to cooldown. Examples include the door-mounted E-Stop pushbutton, and low-low L.O. Pressure or high-high vibration.

And, then there are events that only result in the opening of the generator breaker without shutting off fuel or initiating a shutdown, leaving the turbine running with no load. These are usually called 'breaker open' events.

You also said a "tripping alarm", so that begs the question: How do you know this particular alarm "trips" (initiates an emergency shutdown by shutting of the fuel very quickly)? Because a "Stop" is different than a "trip". (Sorry; but trips and shutdowns <b>are not</b> the same and shouldn't be used interchangeably when talking about GE heavy duty gas turbine operation.)

Was this turbine retrofitted with a Mark V? Older turbines were operated from switches and handles on the Generator Control Panel. If so, it was common for many of the original "controls" (switches, handles) to be reconnected to the Mark V and left enabled.

There are some "emergency stop" input terminals on the <P> PTBA card (terminals 43 through 56; see the figure for "<P> Core - Emergency Trip Pushbutton Connections on PTBA" in Appendix D of the Mark V Application Manual, GEH-6195), and the door-mounted E-Stop push-button is connected to one of those inputs. It's common for a second contact of that switch (or any other switch connected to one of those inputs, or in series with the door-mounted E-stop push-button) to be connected to a discrete input, and that discrete input is used to drive a Process Alarm to indicate which device actually tripped the unit.

As Bob Johnston says, you need to use ALARM.LST to look up the logic signal name that drives the alarm you listed, and then look up that rung/logic in the CSP to see what causes the alarm. It's even bee found that some Process Alarm text messages aren't correct, or are misleading (sad, but true).

So, we don't know if the unit was tripped (emergency shutdown), or automatically shutdown, or experienced a generator breaker open event from your descriptions.

You will need to examine the CSP to see what actually causes that particular alarm message, and then work from there to deduce what happened to the unit.

Note that the tripping inputs connected to the <P> PTBA should be normally closed, and when the contacts, or the circuit, open the unit will be tripped (fuel will be shut off very quickly). Loose wires can cause the circuit to open even if the switch contacts don't (the turbine control panel can't distinguish between an open circuit and an open contact; they're the same as far as the turbine control panel is concerned).

Also note that it's (unfortunately) common for multiple inputs to be wired in series to these input terminals to the Mark V PTBA, so it's sometimes difficult to trace them down from the I/O Report and drawings, if any are available.

I'm NOT suggesting that the cause of the turbine trip (emergency shutdown) was an input to the PTBA card, but if the unit tripped (emergency shutdown) then those input(s) should be checked along the entire length of the wiring, not just the terminals on the PTBA. Don't over-tighten the wires at the PTBA, either; they should be firm but they shouldn't be over-torqued.

It would be very unusual for a Mark V control panel, if configured correctly, to trip or initiate an automatic shutdown without a change of state of some discrete input (either one of the inputs to the PTBA or a discrete input to one of the discrete input cores, <QD1> or <CD> (though it was never intended for trip inputs, or even shutdown inputs, to be connected to <CD> but that didn't stop some people from connecting them to <CD>).

It would also be helpful to know if the Mark V is a TMR control panel or a SIMPLEX control panel.

Also, it's not advisable to force trip or shutdown inputs, nor to jumper E-Stop inputs. They are considered "critical" inputs and as such, they shouldn't be rendered useless without fully understanding all the possible consequences and without the express consent of plant supervision and management after explaining the possible consequences to them.