Low Voltage from Utility 1

[socalguy]

Can low voltage from distribution lines cause electric bills to increase?

 

[Skogsgurra]

In most cases, no.

But electronic loads will usually draw more current - lower the voltage by ten percent and current rises ten percent. Since bills are calculated from wattage, this does not mean a higher bill. But, there are the losses - and they increase with current. So it is possible that there will be a fraction of a percent increase in total consumption. But usually not anything you would notice when compared to normal fluctuations in power consumption.

Incandescent lamps get dimmer and live longer when the voltage is reduced. It also reduces power consumption. So the net effect may be that you win when voltage goes down a few percent.

Gunnar Englund

http://www.gke.org

 

[ScottI2R]

Socalguy,
Listen to what skoggsgura says. This is true. However, Low line V can cause equipment/appliances premature failure.

Scott

In a hundred years, it isn't going to matter anyway.

 

[buzzp]

There was a good research project on this by the EPRI. It is called "The Effects of Reduced Voltage on the Operation and Efficiency of Electric Systems" EPRI EL-3591 in 1984. The report has excellent data on residential and industrial equipment showing the voltage, torque (if applicable), VAR's, I, V, etc. It almost suggests the wattage generally goes down on most equipment with reduced voltage, which would benefit the residential customer. It also suggests that smaller motors operated at nameplate torque also show an decrease in VARs, the extent depends on the load on the motor; light load - more decrease in VARs and W, while a fully loaded motor shows some decrease but not much.
Check it out, the results of the research are very interesting and might surprise you.

 

[buzzp]

I wanted to say you should quantify the extent of the low voltage. Less than 85% or so of nameplate, I think you need to have another discussion with equipment failure, etc.

 

[mikey70]

If your talking about your house, no. Most residential load is resistive, when the voltage goes down the current goes down, reducing demand. Motor loads like pumps, compressors in hvac systems and refrigeration units will pull more amps when the voltage goes down. We ran some tests at the utility I used to work at by reducing the voltage by 5%. On the average residential feeder there was a slight reduction in the watt demand but they never made it a full scale program. If the load is commercial or industrial it would be more inductive and there would likely be no change at all. The real danger of low voltage is overheating motors and compressors. In this equipment the current will go up and the heating effect increases with the square of the current, so you can damage a motor quickly with low voltage.

 

[Noway2]

You mention an unimplemented plan to reduce the voltage by 5%. As an interesting bit of trivia, I heard that a long time ago that the line voltage was lower and it was increased to accomodate higher demands and that this is why it is now 120Vac for single phase residential but is often times called 110. I don't know if it is true or not, though.

 

[waross]

Noway2 I'm sorry, I can't produce the referrence. I did read a long long time ago a report on this subject that stated that the voltage increase program was to be at the rate of 1/2 Volt a year and the target voltage was 150 Volts, but that the project was terminated at 120 volts. And the old timers on the forum may remember when 112 volt appliances were common. 5 years later, appliances were showing 115 on the nameplate. Then 117 Volts. I was in a somewhat isolated rural area where folks never threw anything away. I saw some 105 volt appliances. I think it was sumetime in the late 50's or early 60's that the program terminated at 120 volts.
respectfully

 

[jtkirb]

The losses in your home may go down a little, but the utility losses in the lines going to the house go up. You can imagine what direction the voltage would go if your bills go down with a reduced voltage, but the utility's bills go up.

All the utilities I ever delt with had WAY too much going on to worry about a few cents here or there. The voltage was set to keep the customers at the long end of a line from complaining.

JTK