utility voltage optimization

[steve66]

I've heard from a couple of people that our utility is implementing a voltage optimization program over the next few years.

It has always seemed like most of the electric services run a little hot around here. 480V services often have around 500 V at main panel.

I assume the utilities will be reducing voltages in an attempt to reduce losses and/or to reduce energy consumption. But wouldn't higher voltages result in less current for most loads (motors, lighting ballasts, etc), actually increasing efficiency?

Has anyone else heard about any utilities doing this? Any negative effects on customers?

 

[ggunn]

...wouldn't higher voltages result in less current for most loads (motors, lighting ballasts, etc)?

For resistive loads like incandescent lighting and resistive heating, no; just the opposite will happen.

 

[David Castor]

"Voltage optimization" (VO) generally means voltage reduction. Utilities do this to reduce their maximum demand during high load periods. Lowering voltage generally reduces current and power. Utility can use voltage data from new "smart" meters to monitor voltage and reduce voltage to reduce demand with staying within their +/- 5% allowable range.

 

[steve66]

For resistive loads like incandescent lighting and resistive heating, no; just the opposite will happen.

Yes, but how many people use incandescent lights now? I guess they may be common in residential houses, but I got the impression the voltage optimization is targeting more larger commercial and industrial clients. They generally have almost no incandescent lights - maybe still some fluorescent, but mostly LED now.

And resistance heating is normally controlled by a thermostat. So any attempt to reduce the load by reducing the voltage will just be met by the thermostat keeping the load on longer.

 

[ggunn]

Yes, but how many people use incandescent lights now? I guess they may be common in residential houses, but I got the impression the voltage optimization is targeting more larger commercial and industrial clients. They generally have almost no incandescent lights - maybe still some fluorescent, but mostly LED now.

And resistance heating is normally controlled by a thermostat. So any attempt to reduce the load by reducing the voltage will just be met by the thermostat keeping the load on longer.

I do not know that raising the voltage to LED or fluorescent lighting would lower the current through these devices; that is, I do not know that they are constant power consuming. In general, I don't think that raising voltage lowers current through most loads. If it did, then lowering voltage would raise current and a POCO lowering voltage for energy conservation would be ineffective.

 

[David Castor]

Voltage reduction at the utility distribution system level reduces power demand and energy use. For most utilities the main driver for voltage reduction is reducing their peak demand. But it also reduces overall energy use. It's true that for certain types of loads e.g. water heaters, that it may just be energized longer and consume the same energy in the long run, peak demand is still reduced.