Utility distribution: what is this?

[electrofelon]

I thought maybe a PT for monitoring, but no connection to anything else. Does it have something to do with the arrestors? Its a 4800 delta system, two phases.

 

[augie47]

my $$ is on a capacitor but we'll see what one of the POCO experts say.

 

[meternerd]

Capacitor.

 

[electrofelon]

Ah, Ok. What for?

 

[GoldDigger]

Ah, Ok. What for?

Power Factor Correction on the line. Not necessarily associated with low PF customer loads.

 

[Bugman1400]

Ah, Ok. What for?

Looks like a std distribution cap wired line-to-ground through a fused cutout. Since the picture seems to show a 2-phase supply to some load, perhaps the phase with the cap has much heavier load on it. Otherwise, I would've expected to see two caps instead of one.

 

[mbrooke]

Cap

 

[electrofelon]

This is in a rural area, just scattered houses, middle of nowhere. Would a PF cap be typical for this kind of line and load?

 

[11bgrunt]

Looks like a std distribution cap wired line-to-ground through a fused cutout. Since the picture seems to show a 2-phase supply to some load, perhaps the phase with the cap has much heavier load on it. Otherwise, I would've expected to see two caps instead of one.

I don't see a system neutral. Maybe the arrester on the far side is connected to a cutout we cant see and two hot phases go to the capacitor. I have done this with 14.4kV Delta. Around here a static capacitor will usually be connected in the summer and open in the winter. All about air conditioning load.

 

[electrofelon]

Power Factor Correction on the line. Not necessarily associated with low PF customer loads.

Interesting, could you elaborate? Would that be because the accumulated effects of many small transformers?

I don't see a system neutral. Maybe the arrester on the far side is connected to a cutout we cant see and two hot phases go to the capacitor. I have done this with 14.4kV Delta. Around here a static capacitor will usually be connected in the summer and open in the winter. All about air conditioning load.

This line is 2 phases of 4800 delta.

 

[GoldDigger]

Interesting, could you elaborate? Would that be because the accumulated effects of many small transformers?




This line is 2 phases of 4800 delta.

My impression was that for distribution lines the inductive reactance of the lines themselves contributes to a noticeable power factor effect, but I may be totally mistaken.

 

[kwired]

This is in a rural area, just scattered houses, middle of nowhere. Would a PF cap be typical for this kind of line and load?

It is serving small services - poor power factor is not penalized with those customers, but still exists. POCO places correction where they feel is needed in their distribution, and may even switch it out of the circuit at different times of the year when power factor changes because the general loads have changed (like when air conditioning season ends).

 

[electrofelon]

My impression was that for distribution lines the inductive reactance of the lines themselves contributes to a noticeable power factor effect, but I may be totally mistaken.

I though a distribution line by itself was capacitive not inductive?

It is serving small services - poor power factor is not penalized with those customers, but still exists. POCO places correction where they feel is needed in their distribution, and may even switch it out of the circuit at different times of the year when power factor changes because the general loads have changed (like when air conditioning season ends).
Today, 01:16 AMGoldDigger

I just never noticed these - of course now Ill start seeing them everywhere ...

 

[mbrooke]

My impression was that for distribution lines the inductive reactance of the lines themselves contributes to a noticeable power factor effect, but I may be totally mistaken.

Anyone in the EE field know?

 

[kwired]

The lines themselves should be capacitive in nature, but if you have enough inductive load you still will have a net lagging power factor.

 

[Jraef]

They use caps like that to boost the line voltages on long distance runs. The fact that they only ran two lines indicates it's likely a long run from the nearest substation, meaning they save money on the wire and use an open delta for any three phase loads they encounter on that line.

 

[fmtjfw]

Interesting, could you elaborate? Would that be because the accumulated effects of many small transformers?




This line is 2 phases of 4800 delta.

Where is the neutral? It should be above the telephone line.

 

[electrofelon]

Where is the neutral? It should be above the telephone line.

No neutral, just 2 ungrounded.

They use caps like that to boost the line voltages on long distance runs. The fact that they only ran two lines indicates it's likely a long run from the nearest substation, meaning they save money on the wire and use an open delta for any three phase loads they encounter on that line.

Its 10 miles to the substation. There is a 2 pole transformer platform halfway along which is probably where it drops down to 4.8, not sure what the supply side of those are.

How does a cap boost voltage? Or do you mean indirectly by improving power factor and lowering losses?

 

[peter d]

How does a cap boost voltage? Or do you mean indirectly by improving power factor and lowering losses?

A cap is always trying to oppose changes in voltage. That means when the voltage dips, the cap opposes that change and supplies the needed voltage. So a cap is very effective at smoothing out dips in voltage.

 

[jminer99er]

www.gegridsolutions.com/HVMV_Equipment/catalog/high_volt_capacitor.htm