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Grid Tie Limmiter


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Great plan!!!

Was looking at doing something like this myself, but it just worked out too costly.

Price looks to be around the R2k mark for a 3kW unit.

 

It opens a lot of doors now, especially where the city councils is full of bull, like in CPT :(

 

Thanks leaves :)

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  • 2 months later...
  • 1 year later...

Resurrecting an old topic, but I haven't seen much comment on it.

 

What is the success with using the Grid Tie Limiter?

I'm wanting to install a Grid Tie System and was all excited until I saw the SSEG limitations by City of Cape Town where you're required to install a reverse power flow blocking system. I plan to move load to run during the day (Geyser in winter - I have a flat plate solar heater system but it doesn't get the water up to temp in winter / pool pump in summer and the parasite load running 24/7) but early morning before the sun comes into its own I don't want to start that load and incur Eskom costs.

 

Added to that my, googling has me only finding two manufacturers on the market - Fronius (through ExSolar) and MicroCare (which does not appear on the CoCT Approved PV Inverter list). Are there any others?

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What is the success with using the Grid Tie Limiter?

I'm wanting to install a Grid Tie System and was all excited until I saw the SSEG limitations by City of Cape Town where you're required to install a reverse power flow blocking system. I plan to move load to run during the day (Geyser in winter - I have a flat plate solar heater system but it doesn't get the water up to temp in winter / pool pump in summer and the parasite load running 24/7) but early morning before the sun comes into its own I don't want to start that load and incur Eskom costs.

 

Hi andrewb

 

If I understand you correctly, you want to prevent certain appliances from using grid power "early morning before the sun comes into its own"? You will not be able to achieve that with a grid-tie limiter. The purpose of a grid tie system is to combine solar PV and grid to supply the load and if the load is less than the generated solar PV, the difference is exported back into the grid. If you want to prevent grid export, you add a grid-tie limiter to the system. Biggest drawback with these GTIs are that all of them with a single AC connection switches off the inverter when the grid fails (typical during load-shedding) and then you have NO power to supply your load. The solution to this is a hybrid inverter, e.g. the infini or the more expensive Imeon. Both of then can combine grid and PV to supply your load, both can be configured to export access power to the grid or not export at all and both can still supply your load when the grid fails (during load-shedding).

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Thanks superdiy

Apologies for my ambiguity. I would control the load with timers - geyserwise for the geyser or pool pump timer.

I was thinking more along the lines of only setting the timer to start the load around about the time that power from the PV > 50%. But before then I would have excess power from the PV as I would only be providing power to my parasite loads which is on average around 200W. To avoid the expense of the batteries and accepting that with loadshedding I would have no power I was looking for a solution to prevent the reverse power flow onto the grid. Hence the query re the grid tie limiter.

For now, I have a generator for load shedding times should I need to power the lights at night. Batteries are down the line at this time in my planning and finances.

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Jip, this is still a very big problem.

 

The reverse power blocking unit from the councel, does not really do what it says. The unit only detects reverse power flow and then disconnects the mains power :(

 

The Infini is also not the best, as the exporing of power back to the grid is either on or off.

If there was a sensor one could connect to the main meter to limit the export of power, it would be ideal!

If I could get a 5kw single phase unit, I will be more than happy.

 

So far only Goodwee has a hybrid solution where a device is installed at your meter, to limit the amount of power exported.

Unfortunately according to Mike, his unit had software issues and did not function correclty during power outages.

The price on the unit was also very high.

 

The only real solution I have seen so far that works is from Microcare, but then you need 2 devices.

Looks like this...

http://gbsynergy.co.za/micro/wp-content/uploads/2014/10/Microcare-Wiring-Options-page-006.jpg

 

There might be other solutions, but non that I have seen.

 

And yes, the City of Cape Town is pissing me off endlessley :(

They applying double standards, a$$holes.

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  • 3 weeks later...

Old thread, but in answer to last comment: yes, I believe the microcare grid limiter only works with a microcare bi-directional inverter.

 

On the Victron side: I recently noticed they came up with another hub option: hub-4. And they published details on how to communicate with the "assistant" in the software stack, so in theory you could build your own embedded computer solution to set the feedback level to precisely what is required to avoid feedback into the grid. Now I half suspect they are going to build such a setting into their CCGX computer one of these days... but in the meantime... it is already technically possible.

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