Is Solar supposed to be negative? Our system is showing strange data.
Grid Import should be the sum of all the stacked/filled circuits (power, lights, oven AC), and it is until solar was connected.
Once solar was connected, the grid import should decrease by the amount of solar energy, but since the CT wasn’t connected yet, we only know the inverter was reporting 5kW at that time. The difference is not only not 5kW, but also starts by decreasing the grid export, and then increases it above the sum of its parts.
Later, I set the Solar CT to Reverse, but I don’t know exactly when and I didn’t notice anything. However, there is a spike on the export line that I can’t explain, so it might have been at that time.
When solar was almost 0W (roughly 14W), I realised I hadn’t allowed negative power so I enabled that.
I have no idea how this should be configured. Can I please have some help?
I verified the direction and location of the CTs in the image below.
I didn’t show Main_Line because it’s always the same as Grid_Export (for today).
Screenshot taken after Solar was set to Reverse and Allow Negative Power.
Kind regards,
Dan
Looking at the plot, as you say, it all looks fine up until “solar connected”. At that point, with the solar contributing, your grid import appears to decrease. It’s still early in the day so I think the solar not enough to cause grid export.
A little after 11am the grid import appears to climb to the point where it does exceed your aggregate loads. What I think is happening there is that you probably do not have “allow negative values” checked for your mains and the solar, with the sun coming on stronger, is actually exporting through the grid, but without allowing negative, it’s appearing as import.
Conveniently, the aircon appears to validate the above when at about 3pm it shuts down for a few minutes. At that time, the Aircon had been using about 2kW and the grid was showing about 1kW import which I believe was actually 1 kW export (negative). That 1kW export would increase to about 3kW without the Aircon load, and sure enough, the “import” increased by that amount.
Shortly after that, with the sun waning and the Aircon drawing over 3.5kW to catch up, the “import” number is back in positive territory and you can see that the aggregate load is now the sum of import and solar.
So I think the problem is that you do not have “allow negative values” checked for your Grid CT.
Most solar inverters go negative at night when drawing a few Watts on standby, so allowing negative there is informative.
