More transformer platform porn

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electrofelon said:
How does that work?
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I'm assuming you are talking about the regulator?

Without getting too technical, it basically just monitors the voltage trend, once a downward trend is started a motor starts to change steps ( often in 100 v increments) to maintain voltage. It can either remain there indefinitely or only a certain amount of time. When an upward trend starts, it will revert back to its starting position and remain there for a certain amount of time, before making anymore corrections. This is done to prevent "searching " through the steps.



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truck41trouble said:
I'm assuming you are talking about the regulator?

Without getting too technical, it basically just monitors the voltage trend, once a downward trend is started a motor starts to change steps ( often in 100 v increments) to maintain voltage. It can either remain there indefinitely or only a certain amount of time. When an upward trend starts, it will revert back to its starting position and remain there for a certain amount of time, before making anymore corrections. This is done to prevent "searching " through the steps.



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So basically a transformer with a bunch of taps that are changed by an actuator?
 
electrofelon said:
What tells you its below 5kv?
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The small side mounted bushings, such as those seen here:


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At 7kv and above the are almost always top mounted.
 
electrofelon said:
Cool, I'll keep an eye out for that. Makes sense lots of 4800 around here.
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But keep in mind the dual voltage cans. They have top mounted bushings but are often plenty of the 4800 volt systems. When time come they just flip the switch and the line is at 12470.
 
mbrooke said:
But keep in mind the dual voltage cans. They have top mounted bushings but are often plenty of the 4800 volt systems. When time come they just flip the switch and the line is at 12470.
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Yeah that's what my serving transformer is. I just got hooked up in September and the way the utility does it here is a separate truck comes by a few days before the line crew and drops off the transformer and other parts. So, I got to take a a good look at. They gave me a 25kva which is cool, many residences get 10's. It had a selector switch for 3 or 4 different primary voltages. I assumed that was for convenience of inventory purposes, but I guess it makes sense for planning for easier line upgrades later too.
 
electrofelon said:
Yeah that's what my serving transformer is. I just got hooked up in September and the way the utility does it here is a separate truck comes by a few days before the line crew and drops off the transformer and other parts. So, I got to take a a good look at. They gave me a 25kva which is cool, many residences get 10's. It had a selector switch for 3 or 4 different primary voltages. I assumed that was for convenience of inventory purposes, but I guess it makes sense for planning for easier line upgrades later too.
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Could be for both. Taps are great for POCOs that have multiple voltages in service keeping inventory down- which is great for emergency storm restoration as well. In addition they will almost always replace line hardware and transformers with their desired standardized voltage, and when everything is fully changed over hardware wise, they will then make the switch at once. Its cost and service (outage time) prohibited to do it any other way.

FWIW, around here when POCOs have to deal with a new build a sub division in a 4800 volt delta area they will use 25kv rated cable and pad-mounts and set a jumbo pig at the riser and step up the voltage. A few years latter the line is upgraded to 25kv and the jumbo is simply bypassed.
 
Where I work, they'll send out a troubleman to hook up a new service. As long as its less than 150' of primary line and under a 50 kva transformer it falls under troubleman classification. I'm a shift troubleman on a 24/7 12hr shift rotation. On nights / weekends or weekend nights there is only 2 of us per division; 1 per truck. Its always odd hooking up a new service at 2am on a Sunday morning haha.
25 kva pots have become the standard around here for single residences. The multi voltage ones are nice, you can use them single phase L-L or L-G. Also comes in handy building out 3 phase banks, you can hook your primaries up however you please. I'm not a fan of single bushing pots in a 3 phase bank.


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FWIW, around here when POCOs have to deal with a new build a sub division in a 4800 volt delta area they will use 25kv rated cable and pad-mounts and set a jumbo pig at the riser and step up the voltage. A few years latter the line is upgraded to 25kv and the jumbo is simply bypassed.
Click to expand...



Interesting. Is a lot of your area 25kv distribution? We do this a lot for subdivisions being fed underground from a delta system. We hook the primaries up L-L and the secondary up L-G. It sets us up for when we convert to wye, and it saves the customer an extra run of primary wire.




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