Our gas turbine, GE frame 9E used speedtronic Mark VI. After 3000rpm (full speed no load), we try to synchronize. Some time, with special case, we fail to synchrone before 15 minutes, we can resynchrone to the system (grid). But, after 15 minutes fail to synchore, we can't synchrone to grid. We have to start again from turning gear. Can some body help us to make resynchronize with long time? We need to make efficiency for use our fuel oil.

Thank you

 

Since you say that you achieve the nominal speed of 3000rpm, the only thing that is missing must be the "phase angle matching".

I can think of two things.
The one is to open the "window" of the phase angle which permits the synchronization, if it is permuted by the generator provider.

The second comes from the observation that a lot of time passes and you cannot synchronize. This can happen if you have absolute 3000 rpm (and not 3000,1 for example) and no phase angle matching. Which means that you will never synchronize...

I have experience in water turbines and not in gas so everything I say is not absolute for you, I am just suggesting.

 

If you have a typical Mark VI installation, then your HMI has a Synch Display. On that display, along the left side of the display, are several "lights" (for lack of a better term). They all have to be green in order for Automatic Synchronization to occur. Any one light that does not turn green after speed matching and voltage matching is complete is indicating that one of the permissives (each light indicates a single permissive) is indicative of a problem.

And you shouldn't be waiting for 15 minutes for Auto Synch. If it doesn't happen in 30-60 seconds, then you need to be troubleshooting the problem, gathering data, making copies of Alarm Displays, noting instabilities--something!--beside just waiting and wasting fuel. The Synch Display should list every permissive which must be met for synchronization and the status of every permissive. Sometimes there is a permissive which comes from outside of the Speedtronic to enable synchronization, but that feeds the Auto Synch permissive string in the application code which ultimately drives one of the lights on the display. I find it VERY difficult to believe that all of the lights are green and there are no alarms (Process or Diagnostic) and the unit isn't synchronizing.

I have seen some very flaky and poorly designed secondary disconnects on some of the larger generator breakers, though not for Frame 9Es. If these disconnects are properly made up (firm and secure connections) then all the permissives can still be met but the signal to close the breaker can't get to the breaker close coil. But, that should also be relatively easy for your instrument and control technicians to troubleshoot with a voltmeter using the schematic diagram of the generator breaker close circuit.

Second, if you fail to synchronize automatically, you don't need (typically) need to stop the unit and wait for it to go all the way down to zero speed then re-initiate another START. All you should need to do is stop the synch process from the buttons on the Synch Display. Sometimes there is a button (but not always; there's that consistently inconsistent thing again!) that says RE-INITIATE SYNCH. If you click on that button while the unit is still at FSNL and with Auto Synch OFF, then it should "reset" the Auto Synch function for you to re-start Auto Synch from the Synch Display, and it should work.

If there's no RE-INITIATE button, then with Auto Synch off and the unit at FSNL, you should just be able to select another START from the Main Display (it won't trip the turbine or hurt anything--I promise!), and then go to the Synch Display and re-select Auto Synch.

If you write back for more help, you are going to need to tell us <b>ALL</b> of the alarms, Process and Diagnostic, that are active at the time of the problem. The breaker close relays are located on the TTUR card of a Mark VI Speedtronic turbine control system, so any Diagnostic Alarms from the VTURs or VPROs (which also drive some relays on the TTUR for synchronization) need to be listed in your response.

You are also going to need to tell us exactly which "lights" are green on the Synch Display and which lights are red when the Auto Synch isn't working.

And, you are going to have to describe the grid frequency when you are trying to synchronize (stable, mildly unstable, wildly unstable, etc.). Also you need to tell us, from the Master Select Mode/Indication on the Main Display, what mode the unit is being operated in (AUTO, REMOTE, etc.)

 

Incomplete sequence?

 

> Incomplete sequence?

This is a good possibility, though it would not typically even allow Auto Synch to be selected or enabled if the unit hadn't reached Complete Sequence. And, that would usually be indicated by one of the "lights" at the left of the Synch Display.

If the originator will tell us the alarms which are active when this problem occurs we could rule this out or say it's the cause.

 

It is the 15 minutes from the original post that caught my attention.

The simple answer may be something as silly as a lube oil immersion heater running. This would cause the aux lube oil pump to run. Complete sequence would never be achieved.

The sync protection will not allow a sync without complete sequence. Do you concur?

 

> Our gas turbine, GE frame 9E used speedtronic Mark VI. After 3000rpm (full
> speed no load), we try to synchronize. Some time, with special case, we fail to
> synchrone before 15 minutes, ---- snip ----

Have your GT ever failed to synchronize for the second attempt?

 

>> Our gas turbine, GE frame 9E used
>speedtronic Mark VI. After 3000rpm
>(full
>> speed no load), we try to
>synchronize. Some time, with special
>case, we fail to
>> synchrone before 15 minutes, ----
>snip ----

We have Mark VIe, Per CSA on HMI display on the left side you see all signals, first one in MASTER LOCK OUT ( need MASTER RESET), if this is in, you will never go on GRID. MarkVIe has TTUR and 3 SPRO (x,y,z) cards which are O/S and remote trip configured, but also comes in play when synch. TTUR has three relays, K25A, K25P and K25. I watched these relays during sych. As you approaches 11 o'clock middle relay picks up, remaining two are already picked up, in other words @ about 11 o'clock all three relays pick up for a moment and closing coil for BKR is powered up. I think even synchscope moving it does not mean that relay will work if it is bad, please replace the relay. If your STATUS shows FSNL then synch won't happen, as elsewhere it is mentioned, if ALOP running, ELOP pump under voltage, or LO heater contact shows that it is close, all these reasons will result STATUS as FSNL. Other possibility(but very remote) tiny transformers (one for line and one for generatoron all four cards TTur and three SPRO) may be bad, but as CSA mentions if you see both voltages on HMI then it assures that signal is coming not necessary correct signal. Last, have you check 125 vDC power to the Breaker. Very interesting, Sorry for typo. Please keep posting your findings.
thanks

 

>The sync protection will not allow a
>sync without complete sequence. Do you
>concur?

As was said previously, I believe a failure to achieve Complete Sequence will not allow a typically configured Auto synch to be selected or enabled. Thus, it will effectively prevent an Auto synch.