Well, the power company sent me a letter and guess what? The meter was perfect. I sort of suspected that would be the result when they took it off the house and back to their shop to test it. Now that they have the meter and their test results, there's really nothing further I can do. However the news is not all frustrating. The new meter they left seems to be working fine. My demand usage has dropped to a level that corresponds to what my measurements are and my bill should be dropping accordingly. Seems the highest demand I've had in the last three weeks is 1.5 KW which is a long ways from the 4.2KW I had three months ago.
It's disappointing that I couldn't prove that the meter was set up wrong, but what's one to do?
Wednesday, October 27, 2010
Friday, October 8, 2010
Just an update
Not being one to let something like this go, I dropped a note to the power company to try and make sure they actually tested the meter and let me know the results then called my contact at the government office. A little later I got an email from the power company assuring me that the meter would be tested and the results forwarded. Of course there will always be a nagging doubt about their response since they took the meter away, but what can you do?
Thursday, October 7, 2010
Still haven't heard from the Power Company
Well, it's been a week since the power company was out. Haven't heard a thing. I suspect that I won't hear anything until I make a stink with the government again. The new meter is setting at 1.3 kW which is the lowest it's ever been. They could well have fixed my particular problem; interesting to see what comes of this over the next weeks. I don't plan on going away.
Meanwhile, I've been working on a display computer. It gets the time from NIS and the power from my monitor and displays them. It also forwards the data to Pachube to free up the laptop. I'm waiting on a couple of parts to finish it up and mount it to the wall in the house. Then, it's a toss up between a device to control the two A/C units such that both of them cannot be on at the same time during peak periods or something to control the compressors on my refrigerator and freezer such that they can't be on at the same time. I may just make the first web enabled home thermostat from an Arduino (at least I think it would be the first).
Meanwhile, I've been working on a display computer. It gets the time from NIS and the power from my monitor and displays them. It also forwards the data to Pachube to free up the laptop. I'm waiting on a couple of parts to finish it up and mount it to the wall in the house. Then, it's a toss up between a device to control the two A/C units such that both of them cannot be on at the same time during peak periods or something to control the compressors on my refrigerator and freezer such that they can't be on at the same time. I may just make the first web enabled home thermostat from an Arduino (at least I think it would be the first).
Wednesday, September 29, 2010
Power Company Came to the House
A really nice guy came to the house to check the meter. His work order said that he was sent out on a call to check for a too high reading, nothing to do with demand. He actually couldn't check demand because that takes special equipment that he didn't carry in the field. Soooooo, he tried to check the meter accuracy under load, but couldn't get a pulse reading using a laser to reflect off the aluminum wheel (Arizona sun was too intense) and just pulled the meter and took it with him.
I now have a much smaller, smarter meter that he assures me is programmed for a hour's demand, and the old one will be checked to see how it's programmed and if it is recording accurately. This meter has an infrared pulse output that can be used to measure power. I'm pretty happy with the current measurement techniques so I may not mess with that.
So, it seems they don't understand demand across the company and they can't get a work order correct. The drama will continue since I insisted that I be notified of the results of the tests on the meter. I expect that to happen because the meter guy was really interested in what I was doing and how the meter was actually working.
I now have a much smaller, smarter meter that he assures me is programmed for a hour's demand, and the old one will be checked to see how it's programmed and if it is recording accurately. This meter has an infrared pulse output that can be used to measure power. I'm pretty happy with the current measurement techniques so I may not mess with that.
So, it seems they don't understand demand across the company and they can't get a work order correct. The drama will continue since I insisted that I be notified of the results of the tests on the meter. I expect that to happen because the meter guy was really interested in what I was doing and how the meter was actually working.
Friday, September 24, 2010
Power Company Rescheduled
They were too busy to get to me this morning as planned. They have rescheduled for 0900 next Wednesday, the 29th. This is the second time they have rescheduled.
Wednesday, September 22, 2010
Mathematics of Demand Billing
Some interesting math on Demand. Average is really the arithmetic mean. This is illustrated by:
Which would be expanded to:
1/60 ( X1+ X2 + X3 ....+ X60)
Since each X is the sum of the draw of all of the appliances in the household for a minute and there are 60 of them (60 minutes in an hour) what they're actually measuring is the usage separately for every hour during the peak period for a month and keeping the highest value to be used in billing calculations. This is a rolling average covering every 60 minute period during the peak for the month.
This would mean that a test where a 1000W appliance is run for 15 minutes and nothing else was run for an hour would result in (1000 * 15) / 60 = 250 Watts. Exactly what they are predicting will happen. However, if a base load of 500W runs continuously and we add the 1000W appliance we will get:
((1000 * 15) + (500 * 60) ) / 60 = 750 W
This is completely supported by the data in my previous post where I did the calcs for each minute during the example hour. By the way, my Demand reading so far this month is 1.8kW. Been keeping it pretty lean.
This is going to be an interesting test on Friday. I may come out with egg on my face.
Which would be expanded to:
1/60 ( X1+ X2 + X3 ....+ X60)
Since each X is the sum of the draw of all of the appliances in the household for a minute and there are 60 of them (60 minutes in an hour) what they're actually measuring is the usage separately for every hour during the peak period for a month and keeping the highest value to be used in billing calculations. This is a rolling average covering every 60 minute period during the peak for the month.
This would mean that a test where a 1000W appliance is run for 15 minutes and nothing else was run for an hour would result in (1000 * 15) / 60 = 250 Watts. Exactly what they are predicting will happen. However, if a base load of 500W runs continuously and we add the 1000W appliance we will get:
((1000 * 15) + (500 * 60) ) / 60 = 750 W
This is completely supported by the data in my previous post where I did the calcs for each minute during the example hour. By the way, my Demand reading so far this month is 1.8kW. Been keeping it pretty lean.
This is going to be an interesting test on Friday. I may come out with egg on my face.
OK, so they forecast rain .....
The meeting with the power company has been postponed to Friday at 0900. What? they don't want to work on the meter in the rain?
Actually, neither do I.
Actually, neither do I.
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