Which way electricity will flow ?

[saikat2k2]

May be it is a silly questions but I want to be clear.

Suppose I have installed a 2kWp grid tie system in my house. This PV system is parallel connected with grid incoming line via consumer unit.
Suppose my operating load in the house is 2kW. I mean I am using 2 KW right now.

So my questions is... does this 2kW load power coming from PV (I mean 100% from PV)? or 50% is coming from PV and other 50% is coming from grid?

 

[Bobster]

You own a Masters level degree in electrical engineering and your asking a question like this????

Not only that but you specialize in PV installation design.

 

[TJ Anderson]

May be it is a silly questions but I want to be clear.

Suppose I have installed a 2kWp grid tie system in my house. This PV system is parallel connected with grid incoming line via consumer unit.
Suppose my operating load in the house is 2kW. I mean I am using 2 KW right now.

So my questions is... does this 2kW load power coming from PV (I mean 100% from PV)? or 50% is coming from PV and other 50% is coming from grid?

No, 100% of the inverter output will be used by your household loads, if you are generating more than you are using it exports to the grid. It is interesting how this works. The grid tie inverter must synchronize its frequency with that of the grid (50 Hz) using a local oscillator and limit the voltage to no higher than the grid voltage. It has a fixed unity power factor, which means its output voltage and current are perfectly lined up and its phase angle is within 1 degree of the AC power grid. The inverter has an on-board computer which will sense the current AC grid waveform, and output a voltage to correspond with the grid. However, supplying reactive power to the grid might be necessary to keep the voltage in the local grid inside allowed limitations. Otherwise, in a grid segment with considerable power from PV, voltage levels might rise too much at times of high production, i.e. around noon

 

[akaPABLO]

The law of Physics States you use solar or cover your demand and export the surplus. The 50% rule applies to solar <30kWh only.

But in reality,

All Solar generation goes grid bound and your meter should compensate the transfer. Smart meters are the most accurate at measuring this transfer offsetting your consumption versus generation. Which is why you need to upgrade from analogue.

In reality your neighbour is using your solar and you help the grid by becoming a downstream generator or transformer. The grid will pay you 4.85p /kWh exported and sell it to your neighbour for 15p. They will also compensate your offset usage by your meter. Which means you should pay less at bill time.

If your demand is say 0 you will still only receive 50% export payment whilst giving 100% on domestic unless you have an export MPAN/meter.

 

[TedM]

All Solar generation goes grid bound and your meter should compensate the transfer. Smart meters are the most accurate at measuring this transfer offsetting your consumption versus generation. Which is why you need to upgrade from analogue.

Do you seriuosly believe that?

I'm even more concerned now about the advice you give your customers.

 

[akaPABLO]

TedM - please provide evidence that solar generation is used on site unless it's island mode or battery.

Either way my theory has the same equal benefit to the end buyer what is the difference? If you can prove solar electricity is somehow used on site then please do.

*reclines back in seat whilst TedM googles solar usage in Wikipedia.

 

[BruceB]

While Ted googles that (or not I suspect), you could google Kirchoff's law.

 

[TedM]

@akaPABLO - if you knew exactly how a grid-tied inverter actually worked then you wouldn't even need to ask the question. If you wish to become educated in the ways of PV then you are in the right place, but I think I would be wasting my breath.

 

[ian.settle1]

Down hill if it's on the roof

 

[telectrix]

as long as it's not a flat roof.

 

[akaPABLO]

TedM I admire your wisdom. Do you believe in magic too?

ive found this for you to study and further your pv education

End of the Internet

oh, by the way TJ Anderson is nearly correct with the oscillation but that's just to conform to grid. No solar is used on site whilst grid tied.

 

[Charlie_]

If it's not down hill then you will need an inline capacitor to give it a boost or an electric pump would do the same job

 

[7029 dave]

Down hill if it's on the roof

HA HA like that.

 

[mayfair]

How do you know if your roof is going up or down ? Surely it depends if your above or below it !! I heard of electicity running before ie We now have the electric running Ive even had a client with electric leaking so i suppose anything is possible

 

[davesparks]

If I synchronise a 20KVA generator with a 2.5MVA generator will all of the electricity from the 20KVA set be used first before any from the 2.5MVA set is used?