EKM Metering systems for solar PV?

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JayDee
Posts: 20
Joined: Mon Aug 11, 2014 4:24 pm

Re: EKM Metering systems for solar PV?

Postby JayDee » Thu Feb 26, 2015 1:56 pm

The software determines import from, export to grid, self consumed and generation as well as distribution between peak, off-peak etc, the software records usage @ 5, 15, 30 & 60 minute intervals, PVOutput can be pushed @ 5, 10 & 15 minut intervals with automatic batch upload on missed intervals where captured.

It does this by monitoring power from grid and power from solar generation, if you are looking at just the nett import and nett export component on the main board then yes, the software will handle that however, it would not be able to calculate self consumed unless it is also measuring the generation at the same time, this would need a CT on the inverter line.

Are you able to post a diagram of the two boards and distance between them, what is on the sub board, is generated power used before getting back to the main board.


Cheers

mamrai1
Posts: 9
Joined: Wed Feb 25, 2015 7:31 am

Re: EKM Metering systems for solar PV?

Postby mamrai1 » Thu Feb 26, 2015 10:37 pm

Hi, the subboard is in the garage and controls some lights, the garage door and the central heating system (pumps..). Its around 15meters away from the main board and has a dedicated mcb. I thought about putting some new dedicated wires for the inverter, to distinguish load and generation but there is no way they will fit inside the tubing...
So i was thinking of using pvoutput push to calculate my consumption (=generation+import-export) since i already upload generation directly from the inverter..

JayDee
Posts: 20
Joined: Mon Aug 11, 2014 4:24 pm

Re: EKM Metering systems for solar PV?

Postby JayDee » Fri Feb 27, 2015 1:39 am

Hi mamrail,

need to know what country are you in?

where does the inverter come in, main board or sub board?

does sub board go through a main switch or cb at main board?

mamrai1
Posts: 9
Joined: Wed Feb 25, 2015 7:31 am

Re: EKM Metering systems for solar PV?

Postby mamrai1 » Fri Feb 27, 2015 7:29 am

I live in Cyprus and I have single phase 240v. The inverter has a cb in subboard. The subboard has a cb in main board.

mamrai1
Posts: 9
Joined: Wed Feb 25, 2015 7:31 am

Re: EKM Metering systems for solar PV?

Postby mamrai1 » Fri Feb 27, 2015 10:08 am

photos attached of main and subboard
Attachments
main.jpg
subboard cb is the number 4
main.jpg (170.06 KiB) Viewed 13510 times
subboard.jpg
inverter cb is the last on the right
subboard.jpg (177.91 KiB) Viewed 13510 times

JayDee
Posts: 20
Joined: Mon Aug 11, 2014 4:24 pm

Re: EKM Metering systems for solar PV?

Postby JayDee » Fri Feb 27, 2015 2:04 pm

Hi Mamrail,

The solution for your circumstance would be along these lines.

1 EKM V4 to monitor the main board with a CT on the main line (import / export) and a CT on the sub board line, this will give you total import from grid and export to grid.
1 EKM V4 on the sub board, 1 CT to measure consumption in the garage, 1 CT on the inverter will give you generation.
1 iSerial.

You will be able to daisy chain the two meters with twisted pair wire that should fit in the tubing you already have or run along side if unable to.

An easier (and possibly a cheaper) way might be to run the inverter wires back to the main board, this would mean that only 1 V4 with 3 CT's is needed, this would be a more preffered solution.

MeterMan will give you total import. export and consumption, uploads to PVOutput will give you energy generated, energy used, energy used in this case is the total energy used from import + energy used from self generation.
It will also give you a cost analysis based on tariff import charges, savings from self consumed and income from generation.

Using a V4 will also remove the need to upload generation from the inverter seperately.

Cheers

mamrai1
Posts: 9
Joined: Wed Feb 25, 2015 7:31 am

Re: EKM Metering systems for solar PV?

Postby mamrai1 » Sat Feb 28, 2015 9:28 am

So why can't i use only the first v4 meter for import/export and use push for pvoutput? I already upload generation so consumption will be calculated automatically. Is that correct?
Anyway i understand that pvoutput is very simple and does not have the features of dash but i just want to have an idea if my generation covers my consuption...

JayDee
Posts: 20
Joined: Mon Aug 11, 2014 4:24 pm

Re: EKM Metering systems for solar PV?

Postby JayDee » Sat Feb 28, 2015 2:08 pm

You can use just the 1 V4 for import and export on your main board in doing so you will not get the consumption from the sub board when power is being generated nor will you get the amount of energy you have used from solar generation.

If you are not concerned about not knowing consumption on the sub board then 1 V4 meter is fine.

How do you upload generation, are you already using push?

mamrai1
Posts: 9
Joined: Wed Feb 25, 2015 7:31 am

Re: EKM Metering systems for solar PV?

Postby mamrai1 » Sat Feb 28, 2015 11:50 pm

I upload generation every 5 minutes directly from inverter using oxley solar application.
I thought with only one v4 between the grid and the main board I could log import and export watts with push. Uploading this with ekm push to pvoutput as 'net' direction would give me consumption...

JayDee
Posts: 20
Joined: Mon Aug 11, 2014 4:24 pm

Re: EKM Metering systems for solar PV?

Postby JayDee » Sun Mar 01, 2015 12:59 pm

Hi mamrail,

You are right, 1 V4 between grid and your main board will give you import and export but total consumption (including self connsumed from generation) will only be reliable when you are not generating any power from your solar because it is not being measured that is why a second meter would be needed on the sub board.

If this is of no concern to you then all you need is 1 V4 but remember, energy used on pvoutput will not show you any self consumed energy from solar, I do not know how all applications that upload to pvoutput work but I do know that most if not all do not take into account any self consumed energy (from solar) in their upload.

Sure, generation - (import - export) = consumption but you are not getting the total picture.

You can use push if you want, the question is how accurate do you want to be, if close enough is good enough then you are good to go with 1 V4 and Push.

Cheers


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