Stinsy wrote: ↑Sat Jul 31, 2021 11:16 am
nowty wrote: ↑Fri Jul 30, 2021 4:42 pm
Its likely to be a very small power factor corrector, many domestic appliances have motors (like fridge compressors) or switch mode power supplies which usually means an inductive load. Adding a capacitive load to the mix may help correct poor power factor but you will only save anything against your bill if you are charged in kVAh (Apparent Power) and not kWh (Real Power). And then its got be be big enough and matched correctly to make a difference.
In the UK domestic customers only pay for kWh and not kVAh, so you will save nothing.
I recall my ex-employer was using a similar thing (bank of capacitors) for power factor correction but on a much, much larger scale. But they were saving money as they were billed extra for having a poor power factor.
Interestingly, smart meters do measure kVAh as well as kWh, so maybe in the future ………………
Example, my smart meter says I have a total import of 11278 in kWh (Real Power) or a total import of 11688 in kVAh (Apparent Power).
I guess your grid usage is probably more "reactive" compared with the typical consumer. I assume the initial surge of electric motors is supplied by the grid while your batteries (once they've had time to respond) supply the power to keep the motor running.
I think its mainly my battery inverter, most of them don't measure it but my SMA Sunny Island does and it generally is importing 250 Var (Reactive power) almost all the time, unless it is heavily exporting. However, that is off set from export of reactive power from my Solar inverters so I am a net exporter of reactive power, which I think is a good thing.
Just checked the totals on my smart meter for reactive power in just under 2 years the meter has been fitted,
Q1 - Total Inductive import 131 Varh
Q2 - Total Capacitive import 617 Varh
Q3 - Total Inductive export 2743 Varh
Q4 - Total Capacitive export 736 Varh
PS - I do like the thread name "Wattless current", as it sums up what reactive power is, as consumed in your home appliances. But along the very long transmission lines, thats where the power is lost as heat, more current, more heat. Therefore the power stations need to generate more power than we actually use. And for clarity thats extra power in addition to the pure resistive load of the transmission lines.