Current imbalance on 3 phase on all motors at sewer plant

[hockeyoligist2]

Hockeyologist?
Before-Correction, Ph-Ph Voltage and Line-Ampere Unbalance Factors
Calculated VUFs (Voltage-Unbalance-Factor) were 1.26% per NEMA and 1.27% per IEC Standards. The corresponding AUFs (Amperage-Unbalance-Factor) were 6.3% and 6.9% per NEMA and IEC Standards, respectively. The VUF indicates an incorrect tap-setting was probably the problem! Are they 1% steps!

After-Correction, Ph-Ph Voltage and Line Ampere Unbalance Factors
NEMA and IEC VUFs were 0.21% and 0.24% respectively. But the AUFs, were significantly higher, i.e, 11.3% and 11.2% respectively. Thus, if you are sure of your readings there is still a problem, but it is unrelated to supply voltage!

Before & After Correction Ph-Gnd Voltages
VUFs were 0.9% and 1.8% indicating phase-to-ground capacitances are balanced!

Regards, Phil Corso

If it is unrelated to supply voltage, why does the imbalance go away when running on generator?

 

[Phil Corso]

Hockeyologist...

Provide voltage and current data!

Phil

 

[hockeyoligist2]

Hockeyologist...

Provide voltage and current data!

Phil

I will provide it tomorrow, my notes are in my work truck.

 

[brad9m]

Wait, there some buzz around Charlotte that Progress bought Duke? It was my understanding there is no more Progress. It is all under Duke Energy now.

Yes, Duke bought Progress. What a "merger" that was. Progress CEO was the CEO of the combined company for a matter of hours before the Duke board of directors fired him and replaced him with the legacy Duke CEO, Jim Rodgers.

 

[hockeyoligist2]

POCO did something Friday, while I was off. The plant lost power, and went on generator for about 1 hour.

They called another electrician, just in case something went wrong, since they are nervous.

The other electrician checked everything while it was on generator and the load and voltage was balanced on the whole plant. He checked again after utility came back and everything was balanced and voltages were dead on 480.

We checked everything this morning and the trending charts since the outage and it has held steady all weekend!

Thanks for the help guys!

 

[kwired]

POCO did something Friday, while I was off. The plant lost power, and went on generator for about 1 hour.

They called another electrician, just in case something went wrong, since they are nervous.

The other electrician checked everything while it was on generator and the load and voltage was balanced on the whole plant. He checked again after utility came back and everything was balanced and voltages were dead on 480.

We checked everything this morning and the trending charts since the outage and it has held steady all weekend!

Thanks for the help guys!

They probably fixed whatever they said was not their problem

 

[Hv&Lv]

Yes, Duke bought Progress. What a "merger" that was. Progress CEO was the CEO of the combined company for a matter of hours before the Duke board of directors fired him and replaced him with the legacy Duke CEO, Jim Rodgers.

Yea, I was playing around. I am 60 miles from Charlotte and have been getting letters weekly about the merger. As for poor Bill, give me 44 million dollars and fire me anyday!

 

[Hv&Lv]

POCO did something Friday, while I was off. The plant lost power, and went on generator for about 1 hour.

They called another electrician, just in case something went wrong, since they are nervous.

The other electrician checked everything while it was on generator and the load and voltage was balanced on the whole plant. He checked again after utility came back and everything was balanced and voltages were dead on 480.

We checked everything this morning and the trending charts since the outage and it has held steady all weekend!

Thanks for the help guys!

Call them and ask them what they fixed. I am still betting on a stuck regulator.

 

[hillbilly1]

POCO did something Friday, while I was off. The plant lost power, and went on generator for about 1 hour.

They called another electrician, just in case something went wrong, since they are nervous.

The other electrician checked everything while it was on generator and the load and voltage was balanced on the whole plant. He checked again after utility came back and everything was balanced and voltages were dead on 480.

We checked everything this morning and the trending charts since the outage and it has held steady all weekend!

Thanks for the help guys!

Yeah, I've had the POCO do that to me to, had a church that would lose power briefly in the middle of services, HID lighting, the contractor that wired the building used standard battery backup lights, so they would only blink, then total darkness. (Fixed that problem with an on delay timer and a contactor, they did have the emergency fixtures on dedicated circuits) POCO claimed it wasn't on their end, so I put a recorder on the service. Funny thing, there was a lot of activity by the POCO on the lines all around the church that week, power never dropped again.

 

[Open Neutral]

They probably fixed whatever they said was not their problem

Don't they have to license that technique from the LEC?