3 phase monitoring for PV and Consumption

This is my first post so please go easy on me!

I have installed a 50kW Solar PV system on a large industrial factory and the client wishes to have a display in his reception to show consumption, generation, export and CO2 savings if possible, with the consumption and generation figures the most important. We have tried to use some of the domestic/small commercial systems available on the market, but all seem to have a max CT clamp size of approx 15-20mm window, while the incoming mains has buss bars of 40mm x 4mm, so the clamps wont physically fit them.

Because of the large incoming mains the DNO meter is CT metered at 800:5 ratio, and we have even tried to fit the monitoring devices ct clamps onto the DNO CT's and transform up but this wasnt successful, and also took apart the devices small ct clamps and counted the windings to be 2560 turns, in an attempt to find a large window clamp with similar number of turns.

Can someone please advise me there is a system available on the market or help on designing a system, where the consumption of a large supply and a PV system can be monitored and reported onto a programme and displayed on a screen.

Any advise is greatly welcomed....




Robert Wall's picture

Re: 3 phase monitoring for PV and Consumption

Take a look at MartinR's "Full Fat 3-phase Monitor". You won't be able to use our standard CTs, but Magnelab do some fairly big ones, 3" x 5" aperture is the biggest - OK, they are designed to give 1/3rd of the output voltage we require but by derating a large one, you could put those directly on your bars (we'd need to check with Magnelab first - I don't have the full data for all of their range!). Then for the display, you could have a web browser. In between, you would have an emonBase to feed Ethernet to your own server running emonCMS and feeding the display - and logging all the data.

On the downside, there's probably a steep learning curve for you, you need to build and box the units, and you need to install emonCMS on a suitable machine and learn your way around it, especially if you want to add to it (but your client's IT Dept might help there). The upside is there's nothing proprietary and hidden, full data is available.

I'll go into more detail if what I propose looks promising.

stevenma's picture

Re: 3 phase monitoring for PV and Consumption

I have some larger current transformers from this UK manufacturer on my 'self-imposed' export meter for my 21.84kWp solar PV system.


Robert Wall's picture

Re: 3 phase monitoring for PV and Consumption

That particular range won't do as the aperture is not large enough, but they do have others. The snag is all appear to be 5 A secondaries, so they would need the burden resistor mounting off-board both from the current viewpoint (I think our jack sockets are not rated to 5 A) and heat (5 W dissipation). However, it will be worth an enquiry. Or a visit - they're only 5 miles up the road from me.

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