Hey was hoping some may be able to provide some insight on a generator that is causing some grief to us on our grid.
Engine was recently rebuilt, and a rebuilt/refurbished alternator installed as well.
Now when bringing the generator online we are only able to get up to 300kw out of it before it opens the breaker on a differential trip. This is a 4160v 1500kw gen, the alternator has been baker tested and passed all tests.
The generator is able to handle up to 250kw and no alarms or trips are triggered.
All ct's and pt's replaced and.polarities checked. Any advice would be greatly appreciated. Here is a snippet of the protection faults as well if it helps. Thanks.

 

Hey was hoping some may be able to provide some insight on a generator that is causing some grief to us on our grid.
Engine was recently rebuilt, and a rebuilt/refurbished alternator installed as well.
Now when bringing the generator online we are only able to get up to 300kw out of it before it opens the breaker on a differential trip. This is a 4160v 1500kw gen, the alternator has been baker tested and passed all tests.
The generator is able to handle up to 250kw and no alarms or trips are triggered.
All ct's and pt's replaced and.polarities checked. Any advice would be greatly appreciated. Here is a snippet of the protection faults as well if it helps. Thanks.
View attachment 3957

Hey

Is that new unit installation/commissioning or unit already operated without Differential protection trip?

 

Hey

Is that new unit installation/commissioning or unit already operated without Differential protection trip?

Hey, it was an already existing unit witj protection, that ran for 20k hrs and just had a full rebuild done on it, alternator was also an old piece that was sent out and rebuilt.

 

Hey, it was an already existing unit witj protection, that ran for 20k hrs and just had a full rebuild done on it, alternator was also an old piece that was sent out and rebuilt.

Hey

It would be good to get some trends from this unit with essentials datas like Current Active Reactive power..Power factor load nature

 

@ajb8787...
Welcome to Control Automation
There a relatively simple way to set an "87", and "87N", but it depends on experience of those doing it!
If you, or others in your facility, are confident that working around a live, rotating machine but separated from the load bus, I will post the procedure to this forum!
Regards, Phil Corso (PE, retired but still "energized")

 

@ajb8787...
Welcome to Control Automation
There a relatively simple way to set an "87", and "87N", but it depends on experience of those doing it!
If you, or others in your facility, are confident that working around a live, rotating machine but separated from the load bus, I will post the procedure to this forum!
Regards, Phil Corso (PE, retired but still "energized")

Hey thanks, yes we have some pretty competitive individuals here I would appreciate seeing the procedure, thanks a lot to both of you for the replies. I will try to get some some data for you today as well controlsguy25

 

*competent, not competitive.

 

@ajb8787...
'87' Test attached!

 

Generator tripping on differential protection relay
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Thread Starter
ajb8787

Yesterday at 1:48 PM

• #1

Hey was hoping some may be able to provide some insight on a generator that is causing some grief to us on our grid.
Engine was recently rebuilt, and a rebuilt/refurbished alternator installed as well.
Now when bringing the generator online we are only able to get up to 300kw out of it before it opens the breaker on a differential trip. This is a 4160v 1500kw gen, the alternator has been baker tested and passed all tests.
The generator is able to handle up to 250kw and no alarms or trips are triggered.
All ct's and pt's replaced and.polarities checked. Any advice would be greatly appreciated. Here is a snippet of the protection faults as well if it helps. Thanks.

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ControlsGuy25

Yesterday at 2:57 PM

• #2

ajb8787 said:
Hey was hoping some may be able to provide some insight on a generator that is causing some grief to us on our grid.
Engine was recently rebuilt, and a rebuilt/refurbished alternator installed as well.
Now when bringing the generator online we are only able to get up to 300kw out of it before it opens the breaker on a differential trip. This is a 4160v 1500kw gen, the alternator has been baker tested and passed all tests.
The generator is able to handle up to 250kw and no alarms or trips are triggered.
All ct's and pt's replaced and.polarities checked. Any advice would be greatly appreciated. Here is a snippet of the protection faults as well if it helps. Thanks.
View attachment 3957
Click to expand...

Hey

Is that new unit installation/commissioning or unit already operated without Differential protection trip?

ControlsGuy25.
Experienced Controls systems Technical Advisor ( worked on 25 projects in 20 countries worldwide) .
Power Generation & Industrial systems .
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ajb8787

Yesterday at 3:28 PM

• #3

ControlsGuy25 said:
Hey

Is that new unit installation/commissioning or unit already operated without Differential protection trip?

Hey, it was an already existing unit witj protection, that ran for 20k hrs and just had a full rebuild done on it, alternator was also an old piece that was sent out and rebuilt.

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ControlsGuy25

Yesterday at 4:37 PM

• #4

ajb8787 said:
Hey, it was an already existing unit witj protection, that ran for 20k hrs and just had a full rebuild done on it, alternator was also an old piece that was sent out and rebuilt.

Hey

It would be good to get some trends from this unit with essentials datas like Current Active Reactive power..Power factor load nature

ControlsGuy25.
Experienced Controls systems Technical Advisor ( worked on 25 projects in 20 countries worldwide) .
Power Generation & Industrial systems .
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PhilCorso

Yesterday at 9:01 PM

• #5

@ajb8787...
Welcome to Control Automation
There a relatively simple way to set an "87", and "87N", but it depends on experience of those doing it!
If you, or others in your facility, are confident that working around a live, rotating machine but separated from the load bus, I will post the procedure to this forum!
Regards, Phil Corso (PE, retired but still "energized")

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Thread Starter
ajb8787

Today at 2:55 AM

• #6

PhilCorso said:
@ajb8787...
Welcome to Control Automation
There a relatively simple way to set an "87", and "87N", but it depends on experience of those doing it!
If you, or others in your facility, are confident that working around a live, rotating machine but separated from the load bus, I will post the procedure to this forum!
Regards, Phil Corso (PE, retired but still "energized")

Hey thanks, yes we have some pretty competitive individuals here I would appreciate seeing the procedure, thanks a lot to both of you for the replies. I will try to get some some data for you today as well controlsguy25

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ajb8787

Today at 9:34 AM

• #7

*competent, not competitive.

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PhilCorso

3 minutes ago

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• #8

@ajb8787...
'87' Test attached!

 

@ajb8787...
Were u able to retrieve the "87" and "87N" Test procedures, despite the Forum's Refusal to accept my files because they were too large?
Regards, to all!
Phil Corso (PE, somewhat retired)
PS: there are Sensitivity and Stability checks as well, if needed!

 

@ajb8787...
Were u able to retrieve the "87" and "87N" Test procedures, despite the Forum's Refusal to accept my files because they were too large?
Regards, to all!
Phil Corso (PE, somewhat retired)
PS: there are Sensitivity and Stability checks as well, if needed!

Hey, yes I was thank you very much. Appreciate the help from both of you in the thread. Found a couple ct wires that were mislabeled causing all the issues. Thanks again and taker easy.

 

Hey

Thank you for the update !

All the best

 

This is a classic differential problem. I recommend a simple check first generally the CT phasing does not match even though the polarities are correct.