Automatic Voltage Regulator

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Grouch

Grouch

Senior Member
Location
New York, NY
A building manager is mentioning the utility is lowering the voltage to one of their buildings. I have to speak to them again as to why.

Is there such a device as an automatic voltage regulator that serves the entire building, connected before or after the service equipment?
 
Knightryder12 said:
There are voltage regulating transformers out there. How big is the service to your building?
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Haven't been to the building yet, so no idea.

Does the voltage regulating transformer work automatically? For example, if the utility voltage goes back to normal, what happens at the output of the transformer? Is there now an overvoltage?
 
Grouch said:
A building manager is mentioning the utility is lowering the voltage to one of their buildings. I have to speak to them again as to why.
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That seems to be pretty common right now. I've heard the same thing from a few clients. According to AI:

Reduce peak power demand and energy costs

Why are utilities lowering the voltages on services?​

Utilities are lowering the voltages on services to reduce peak power demand and energy costs. This is achieved through conservation voltage reduction (CVR), which involves intentionally lowering the voltage on primary distribution circuits to maintain voltages on the secondary side within the acceptable range. By doing so, utilities can achieve significant energy and peak demand reduction at little cost and without impacting customers through load shedding or equipment investments. This practice helps utilities maintain uninterrupted service to customers during peak load periods when electric energy may be in short supply.
 
steve66 said:
That seems to be pretty common right now. I've heard the same thing from a few clients. According to AI:

Reduce peak power demand and energy costs

Why are utilities lowering the voltages on services?​

Utilities are lowering the voltages on services to reduce peak power demand and energy costs. This is achieved through conservation voltage reduction (CVR), which involves intentionally lowering the voltage on primary distribution circuits to maintain voltages on the secondary side within the acceptable range. By doing so, utilities can achieve significant energy and peak demand reduction at little cost and without impacting customers through load shedding or equipment investments. This practice helps utilities maintain uninterrupted service to customers during peak load periods when electric energy may be in short supply.
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The thing with this is, it's fine for resistance heating loads and most lighting, but it's a problem for sensitive electronics and AC motors.

Grouch,
The best approach is to talk to the client and ask them what problems they are having (or perceiving to have) and addressing them there. Yes, you can get a source transformer with Automatic Tap Changers to help regulate the voltage, but unless the client buys his power in bulk and owns his service transformer himself, the utility is not going to provide him with a means to thwart the very program that they have initiated. So the only approach he may have open to him is to identify the critical sensitive loads and add power conditioning just to those specific loads. There are many different ways to skin that cat, depending on the nature of the load involved.
 
Jraef said:
The thing with this is, it's fine for resistance heating loads and most lighting, but it's a problem for sensitive electronics and AC motors.
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Makes sense.
Jraef said:
Yes, you can get a source transformer with Automatic Tap Changers to help regulate the voltage
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This would be installed prior to the service equipment? And it automatically regulates the output voltage to the building?
Jraef said:
So the only approach he may have open to him is to identify the critical sensitive loads and add power conditioning just to those specific loads. There are many different ways to skin that cat, depending on the nature of the load involved.
Click to expand...
Got it.
 
I think @Jraef is describing using utility type transformers with automatic tap changers.

I have absolutely zero experience with these systems, but there are systems that are basically autotransformers with tap changers intended to provide voltage regulation after the service equipment. See, for example:

SureVolt™ - UST

ustpower.com ustpower.com
 
A little off topic:
Many modern devices like appliances, HVAC and motor drives have Switch Mode Power Supplies (SMPS).
SMPSs don't much care about line voltage. If the line voltage drops they draw more current and if the voltage increases less current.
This is the opposite of a resistive load.
 
The utility will only lower the voltage to about the nominal voltage at the service point.

Before, we could almost always count on our local utility running a little hot - a 480V service would usually run around 500 volts.

So at the lower voltage, motors will draw a little more current. (So will any other regulated load - like fluorescent ballasts and LED drivers.) More current means also more voltage drop along the service, feeders, and branch circuits.

So that can be a double whammy - lower voltage to start with combined with slightly more voltage drop on the way to the load, especially where the service point is a long way away from the bulk of the load.

But it shouldn't really be a problem for anywhere that was properly designed and installed, with voltage drop taken into account.

It's more likely to be a problem where voltage drop was ignored (or worse - where it was assumed the service voltage would be high to start with), or places that have had loads haphazardly added everywhere.

It could also be a problem where panels and breakers are already almost loaded to their maximum capacity.

But otherwise, I don't know why the voltage would need regulated or boosted back up.
 
Grouch said:
Haven't been to the building yet, so no idea.

Does the voltage regulating transformer work automatically? For example, if the utility voltage goes back to normal, what happens at the output of the transformer? Is there now an overvoltage?
Click to expand...
Yes, they do work automatically. The ones we have specified before have a + or - of 10% correcting capability.
 
Look into Blackhawk power "Power House". I have installed 3 of these at a battery plant. Some blogs will tell you it's "snake oil" on energy savings. I know for a fact, watching these in action they work to stabilize voltage. Corrects phase imbalance.
 
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