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MK2PV for Zero Export Limiter


(Serg) #1

Hi Community,
Have been searching of how to maximise the self-consumption on a grid tie connection without batteries with Zero Export Limitations to the grid.

MK2PV system uses parameters from variables that have been already exported to the grid, so it calculates an Energy Bucket that is the energy that can be diverted. In this case I cannot measure those units as it will be zero export.

The inverter, has got a dry contact that can be activated according to a certain Energy Bucket and then it will trigger the dump load. The problem is that the heater consumes 1,5kw so when switched ON this will be consuming power from the grid. The PV array will be around 2-2.5kw.
Was thinking in building a PWM regulator within an Arduino but again I don’t know from where to get the variables to monitor that Energy Bucket which would allow me to regulate the power going onto the heater.
Any ideas will be welcome.

Thanks,


(Robert Wall) #2

Robin Emley’s Mk2 PV router DOES achieve zero export when used with a compatible meter (beware, some are not). Your meter is incompatible if the size of the energy “bucket” is less than the energy bucket of the diverter (router).

The Mk2 router does not communicate with your inverter, and it does not turn on the dump load unless there is an excess of generation over consumption. When that happens, it balances the average power to the dump load so that zero average export is maintained. It will fail only if you can generate more than can be consumed by the dump load plus the load from any other apparatus in your house that happens to be working at the time.

Have you read the ‘Learn’ article about PV diversion, in particular Section 9, and followed the link to the archived forum page where all the Mk2 variants are listed?

There you should find links to the Mk2_PV_phaseAngle diverter, and further down the list Using an Emontx V3.4 as a MK2 PV Router with phase angle control.

Phase angle control should mean that a diverter using it is less likely to be incompatible with your meter, but it does pose many more problems in that more filtering will be required and it will be much harder to avoid generating interference.