Mark VI alarm

M

Thread Starter

madmax

Hi Everybody,

Just wanting some help on an intermittent Mark VI (GE)alarm. " Loss of DC power to DGP Trip circuits". It sounds pretty serious, but it doesn't trip the unit and doesn't prevent startup. It (of course) doesn't stay in long enough for me to troubleshoot it.
 
Hi madmax,

"DGP" is usually the acronym for 'Digital Generator Protection' relay. A loss of DC power to the DGP would likely mean that it could <b>NOT</b> trip the generator breaker and/or turbine if there was a problem that required the generator breaker to be tripped and/or the turbine be tripped....

Please write back to let us know what you find.
 
Dear Madmax, it would be most helpful, and allow us to help you best, if you can provide as much information as possible about your unit. This information would include:

Type of machine (Frame 7 EA, FA etc)
Control system (MKVI in this case I think)

When the alarm happens, what you have done to troubleshoot, and when this problem started.

Ok so I will get off my soapbox. It will still be difficult for us to help because we can't see the logic running for your machine, and there isn't a great way to "share" your .m6b file. Also many times we would need to see prints for wiring of your unit, that are hard to "share".

But if I use a .m6b file I have for what I "assume" is a similar unit here is what I can offer.

Alarm " Loss of DC power to DGP Trip circuits".
When I trace this alarm L741_2_ALM it comes from a contact input to the MKVI. This contact is not inverted so it takes a "1" to make it true. This is where I or you would need to refer to your generator protection prints to find out what feeds this input. I'm guessing it may come from the DGP protection relay, or from some sort of monitoring relay that is tied into the trip circuits for the "86" relays to trip the unit or generator breaker.

I would suggest you fully review the prints and determine what could cause this input to the MKVI to go true. Once you understand what can cause it you should be in a better place to monitor the circuits and determine what is causing the intermittent condition.

But be careful, as you said it has not tripped the unit, it is only an alarm at this point. But there could be a loose wire or terminal block causing the alarm, that when manipulated could have an "unintended consequence", and I really hate those!

Let us know how you proceed so that we can learn from your experience.
 
Dear All,

Thank you all for your help. Yes it is indeed on a Frame 7 FA with Mark VI Control System. I will proceed to the full review of the prints. So far, it has not tripped the unit, nor has it given us a not ready to start. We are a peaking facility, so I do have some opportunity to t-shoot with less risk. It is a troubling problem, considering that it could NOT trip the unit if there was a problem. I will keep everyone updated.

Thanks Again.--Max
 
Dear Max,

thanks for the feedback. I will look forward to more information from you as you dig deeper into the problem. As you mentioned, this is an important alarm if the unit is unable to trip the breaker or itself when needed.

Good luck!
 
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