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January 12, 2016, 06:03:12 PM |
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A few years ago my electric utility replaced the old power meter with a phone home communicating power meter that doesn't require the utility to stop at my home and read the meter. I wonder about its accuracy. I know I can shut down everything in the home and put a few hundred watt incandescent lamps as the only use and accurately measuring the current and voltage get a resistive load comparison to compare with the meter reading but my miners might run with a power factor of 0.70 according to my Kill-A-Watt. Of course I could shut down everything and only run a single miner for some hours and get a comparison but shutting down everything isn't something I want to do.
The utility station is maybe 20 miles away, provides power to the entire southeast, and at the time of construction was the largest natural gas power utility in the world. Before the entity purchased the local utilities, and there is some not-too-distant hydroelectric, this rural property was seeing AC voltage levels at 126VAC-128VAC but since the new utility I see voltage pretty close to 120VAC.
When it was 126-128VAC the old incandescent lamps would draw more current and use more power than at 120VAC but air conditioning and refrigerators ran more efficiently and this being the south and hot it made a difference. Now with the power savings lamps the load is more refrigerator, freezer and air conditioning and the lower voltage has those running less efficiently. Interestingly when the voltage was dropping from 126-128VAC, the power lines were falling to the ground mid-summer in Pennsylvania. Apparently there had been a trickle up effect and I think they got caught with their voltage down. The profit change probably saw them lowering their voltages which heated their lines and caused them to break. But that's neither here nor there.
Another aside - when a large company moved down here in '80's, they had electric problems and had their local utility out to the factory in the middle of the night not infrequently until the problems cleared up. The company used a lot of electricity in the production of their product. They knew their usage from having run the same machinery up north. I don't know but suspect there was some kind of overcharging going on and when it was fixed the late night problems requiring the utility visits stopped. But I don't know.
So, the new power utility may be selling more power at 120VAC rather than the 126-128VAC but I would guess the power meters may be better than under the old system. But I don't know.
I should mention that years before the change I had the old company shut off my yard light atop the power pole saving me, I forget, $10 or $15/month. A few years later I saw the charge on the bill again but the light had never been turned back on. I brought all my bills to the utility, showed them the charges and was compensated for the $200+ overcharge. That being the case there would possibly be motive for an installer to 'tweak' this power meter when it went in.
How would I find out if the power meter is accurately computing the power factor and how much would that calibration check cost?
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