Author Topic: MTU Layout Problem  (Read 3650 times)

Wouter

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MTU Layout Problem
« on: November 20, 2011, 04:36:33 AM »
Don't know where I am going wrong.

I have MTU 1 as Adjusted load attached to the Main.
I have MTU 2 as Generation attached to the Wind Turbine.
I have MTU 3 as Stand Alone attached to the line to a sub panel.

Below is a line diagram of the layout.

When there is no power generation, MTU 3 consistently shows higher consumption than MTU 1.  This does not make sense.

Where there is Power being generated... MTU 1 shows higher consumption than MTU 3.  This doesn't really make sense either.

When there is Power being generated... a fourth NET line appears in Footprints that appears to be correct.  Even showing that I am net metering at times.

Where have I gone wrong in my configuration?

I appreciate any help.  I've struggled with this for a while now.

Wouter
« Last Edit: November 20, 2011, 04:42:13 AM by Wouter »

pfletch101

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Re: MTU Layout Problem
« Reply #1 on: November 20, 2011, 07:04:43 PM »
TED's labelling is confusing!

If you download data, you get the raw data from each MTU (but the count is zero-based, so what you are calling MTU 1 is actually called MTU 0, and so on. For the purposes of Footprints, "MTU 2" continues to show the generation numbers, but "MTU 1" shows the computed total power consumption (whether supplied by the utility or generated locally) and "Net" shows the raw data from the "Adjusted Load" MTU. It sounds as if your setup is correct, but you are being justifiably confused by the labelling.

BTW, to add to the confusion, the Remote Display shows actual data, but numbering the MTUs with a 1 base, so, on the remote display, MTU1 is the net value from the MTU on the utility feed and MTU2 is generation. Go figure!
« Last Edit: November 20, 2011, 07:20:55 PM by pfletch101 »
Peter R. Fletcher
TED Pro Home - main MTUs monitoring utility and PV Solar feeds; 2 Spyders monitoring selected individual circuits

Wouter

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Re: MTU Layout Problem
« Reply #2 on: November 20, 2011, 08:17:41 PM »
I think I understand what you are saying, but it is not the download that is the problem.

In the picture below, MTU1 is Blue(Main), MTU2 is Green (Turbine), MTU3 is red (sub panel), and Orange is NET as calculated by Footprints.

Red (subpanel), should never to greater than Blue(main) unless Green(turbine) is generating power. 

Wouter

rotus8

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Re: MTU Layout Problem
« Reply #3 on: November 20, 2011, 08:32:15 PM »
The labeling is indeed even more confusing. With MTU1 set to adjusted load, the NET line is actually what MTU1 is reading. The data shown for "MTU1" is really the actual MTU1 data plus the generation, your MTU2.

There is something strange about your setup though: an MTU set up as generation should always show a negative number, but your turbine line looks to be positive.

Wouter

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Re: MTU Layout Problem
« Reply #4 on: November 20, 2011, 09:25:28 PM »
Yes sorry,

I was playing with the settings and forgot to put them back before I took the screen shot.

I'll do another one as soon as the wind picks up.

Wouter

rotus8

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Re: MTU Layout Problem
« Reply #5 on: November 21, 2011, 12:29:21 AM »
Good, that's better. When I said "The data shown for "MTU1" is really the actual MTU1 data plus the generation, your MTU2", realize that since the generation will always be negative, adding it is actually a subtraction. The result should be the "NET" data shows what your net meter says, the "MTU1" data shows your usage exclusive of generation.

Wouter

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Re: MTU Layout Problem
« Reply #6 on: November 21, 2011, 07:52:26 PM »
Here is a corrected screen shot.

Wouter

rotus8

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Re: MTU Layout Problem
« Reply #7 on: November 21, 2011, 08:47:27 PM »
Ok, this mostly makes sense. Your green line is generation, and can only be negative. Your blue line is "MTU1" which is really the calculated usage, actually the real measured MTU1 with the generation added (actually subtracting because generation is negative), and the orange line is the NET, what your net meter should be reading.

The mystery is why the red line is greater than any of it, I suspect a connection or configuration problem. Or possibly the problem is with MTU1 - how does the NET value compare to your meter? That will help determine which has the problem.

Wouter

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Re: MTU Layout Problem
« Reply #8 on: November 22, 2011, 01:14:15 AM »
That's a good idea.

I'll pick a couple of days and track usage on both my power meter and on footprints.  Perhaps the MTU is out.


An alternative is to swap the CT's on MTU 1 and 3 and see what happens.  If I get the same output, then I will know it is NOT the MTU's.

Wouter