Attached is the picture of the meter with the wiring I recently corrected. I am pretty confident that the wires are connected correctly but will check tomorrow. There are 4 CT's, 2 for each 200A box. The breaker panels do not adjoin each other so I had to run about 10 feet of wire to combine the CT's. It's twisted 18g wire. One of my concerns is that the main feeds are swapped in the boxes.
For an electrician out there, please help clarify something for me. When documentation talks about L1 and L2, I have been assuming that is the left and right sides of the main feeds to the panels themselves. See attached picture. I've also been assuming that when the meter calls for connection to L1 and L2 (the meter is 240V) I ran wires from the left and right banks of the breakers from one that had 240A wired. Clarification appreciated.
I've ordered a new volt meter and should get it in a couple days to check that L1 is indeed L1 and not swapped in the boxes. Will also check whether L1 from the inverter is correct. There is an emergency shut off between the inverter and the panel that AC feeds into not included in the schematic. An earlier questions was whether there were 200A breakers for each panel. Yes, each panel has a 200A breaker.
I appreciate everyone's thoughts, ideas. and clarifications. I agree with whoever said it's complicated, the whole system is complicated. Where I live we have no code or local inspections for residential, as such, I am leery of everything about the panels, grounding, feeds from the utility, etc.
The pictures were taken at different times so as I've been debugging and wire chasing. things changed. The picture of the meter is the latest configuration, the picture of the panel that has the meter in it is older. For those interested, pics of the system are attached that can matched to the drawing.
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John Gillispie
johnp250@yahoo.com------------------------------
Original Message:
Sent: 12-01-2021 05:26 PM
From: Ken Nadsady
Subject: Challenging Issue
No, the CT's should not be in series. To combine readings of two CTs measuring current in two different conductors, you put them in parallel as shown in the link here, from the manufacturer of the SolarEdge CT's that John has in his system:
https://ctlsys.com/support/paralleling_current_transformers/
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Ken Nadsady
AviSun Renewable Energy
Hudson OH
Knadsady@avisun.net
Original Message:
Sent: 11-30-2021 10:56 PM
From: William Kaszeta
Subject: Challenging Issue
John,
Your panel CTs need to be in series. That way currents in each panel add to each other. The two L1 CTs are in series, etc. If they are in parallel you will get the average, not the sum.
To check that L1 is the same in both panels, simply measure the voltage between the two L1 busses, should be close to zero. If you get something about 240Vac they are not on the same line. They need to match L1 in the inverter.
CAUTION: You do not want to disconnect the CT leads and try to measure the voltage, it can be very high without loading resistor that is internal to the energy meter.
These CTs that are on Panel 1 and Panel 2 are Grid Connection Point meter (Export/Import)
Your drawing does not show any circuit breakers or disconnecting switches. If your "Utility feed & Meter" includes two 200A circuit breakers (so that you can disconnect the cables to the panels safely) and if the CT hole is large enough for two of the wires (3/0 or 4/0 CU?), you can simply route both L1 wires through one CT.
I hope this helps.
Bill
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William Kaszeta
President
Photovoltaic Resources International
Mesa AZ
bill@kaszeta.org
Original Message:
Sent: 11-30-2021 07:32 PM
From: John Gillispie
Subject: Challenging Issue
There are two sets of CT's, one for each of the breaker boxes and are wired to the meter in parallel. The CT's are pointed at the grid per the arrow on the inside of the CT openings.
The local utility will not allow any customer equipment in the meter setting as the installer wanted to put them there. Installer asked for options from Solaredge and they said to put the CT's in both boxes and wire them in parallel. Utility has tested their meter and its within .0010-.0015 on both legs both import and export.
I need a new volt meter to get measurements. How do I check that L1 is the same in both panels? L2? I've suspected that the feeds got swapped in the boxes and that could cause anomalies.
I've read the manual (https://www.solaredge.com/sites/default/files/se_energy_meter_with_modbus_installation_guide-na.pdf) and I am not 100% sure whether my meter would be defined as Load Connection Point (Consumption?) or a Grid Connection Point meter (Export/Import?) (see page appendix C on page 42 in the manual). Right now the inverter thinks the meter is a Export/Import.
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John Gillispie
AARP
johnp250@yahoo.com
Original Message:
Sent: 11-30-2021 01:23 PM
From: Robert Foster
Subject: Challenging Issue
Hi John
Sounds like your CTs are installed backwards. Double check them.
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Robert Foster
Assistant Professor
New Mexico State University, College of Engineering
Las Cruces NM
rfoster@ases.org
Original Message:
Sent: 11-26-2021 11:44 AM
From: John Gillispie
Subject: Challenging Issue
Hi all,
I've been dealing with a measurement issue for a couple months that I've been unable to determine root cause of. I have a unique set up as I have 2 - 200 amp panels (total of 400 Amps), feeds from electric company are 200 amps. I have a SolarEdge StorEdge single phase inverter with 8.9 kWh of panels behind it with a LG 10Kwh battery. I have a SolarEdge meter with CT's to both panels hooked up in parallel to the meter. The meter is correctly connected to the power system and CT's but when measurement calculations are done it is essentially backwards. The SolarEdge app shows export to the grid when it should be import from the grid and draw from the grid is shown but summed with the production and shown as consumption.
The only number that is right above is the production number. The import from the grid should be export to it and consumption should be the difference between production and export so in the example above the house should be consuming ~1.28Kw.
So, the question is what setting is wrong or are the CT's facing the wrong direction? Right now the settings have the meter as Export/Import but I wonder whether it should be set as a Consumption meter. The CT's are facing the grid and are connected on the feeds to each panel. A complicating factor is that I am not sure that L1 in both panels is truly L1 or whether they got swapped during wiring of the house (I'm not the original owner) and I'm not sure how you validate that the L1 side of each panel is the same from the utility. If they are indeed swapped it should be as easy as switching the CT's in one box.
Now you are probably wondering how I got to this point after 3 years of operation and that is a valid question. My utility only read once a month on a variable schedule and I could get daily readings from Solaredge so I took the consumption and export readings from the utility and the production numbers from SolarEdge. When the utility swapped the meter I could get daily readings and in the process of reconciling the two I found very high variance both high and low and after quite a bit of investigation discovered numerous issues in wiring the meter and connecting the CT's in the two panels together that are now corrected but the math the inverter is doing is wrong but I suspect that is because the configuration is wrong.
Some of you would probably say "make your installer fix it" but my installer is 200 miles away so its not as simple as saying "fix it", they are primarily in the commercial side and no longer operate a residential business and are willing to help but like many things, if I can figure it out and fix it on my own everything would be easier.
Any idea's are welcome. My next step is to change the meter to a consumption meter in the inverter settings and see what happens. I am running out of ideas….
Regards,
John
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John Gillispie
AARP
johnp250@yahoo.com
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