600v Delta System

[KBElec]

Good day all. I have a 600v delts service in an arena. I have a 600v ground fault indicator lights system. A and C phase the light seems normal the B phase is twice as bright. When I test line to line with all loads on I am reading around 575v on each line to line. When I meter line to ground I am reading 319v on A, 463v on B, and 278v on C. when I turn the main disconnect off and do readings on phase to phase and phase to ground I am getting the same readings as stated. This is where it gets weird. So with the main off, and I turn just the ground fault indicator light system off. my voltages from line to ground correct themselves. Ok to re iterate. so I have turned the main off. so everything on the load side of the disconnect has no power, although all the switches are still on even the ground indicator light system is still on but no power going to anything. I turn the switch off and test again and the voltages are corrected. What is going on. So what else have I done. so I eliminated all of the load on the load side of the main disconnect except for the ground indicator light. The lights where still the same A,C still normal B phase twice as bright. Normal this tells me in my experience that the problem is outside. Next I had hydro come, in the past I have found the solution to this problem to be loose connections on the transformer cans. They tel me all connections are fine and that they then installed their own ground indicators on their primary line to the building and that they are not finding any issues. So back to the drawing board. I thought maybe its a grounding issue so I have now removed the main ground and put in a brand new temporary ground, it did not make a difference. Im kind of at a stand still. here in Ontario I cant seem to find a new ground fault indicator light system as this is about the only other thing I think I can do is replace the existing 600v ground indicating light system. But rally what can go wrong with this other than blowing a bulb? anyone have any other ideas?

 

[waross]

Roll the connections to the ground detector. See if the high voltage follows the ground detector.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[KBElec]

Hi Waross Im not sure what you mean by roll the connections to the ground detector?

 

[unclebob]

KB, he means to A->B, B->C, C-> A. See if the light pattern have change. BTW, what is the primary connection of the transformers, delta or wye?

 

[KBElec]

Hi Uncle Bob , thanks for clearing that up. The incoming is delta. In Ontario you need to have this light system to pre warn of issues and if you don't have one ESA can shut the power down to your building. I have order another light indicator on order. I going to try changing that out this is the last option I can come up with. Really stumped on this one.

 

[waross]

If the unbalance goes away when the ground indicator is disconnected that is a good indication that the ground indicator is at fault.
Rolling the connections is the accepted troubleshooting procedure.
Has a lamp been changed for one that does not match the other two lamps?
Try changing all three lamps for three new, identical lamps.


Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[KBElec]

Yes we checked the lamps they are all the same that was one thing I had though maybe someone put the wrong wattage in or a different lamp. Will have to see what the new ligt indicator I baught does, but its 3 weeks to get it uugghhh I will let you know if this corrects the fault.

 

[waross]

Did you roll the connections of the ground detector?

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[KBElec]

I didn't to be honest, you mean just to see if the bright light follows the phases right