half hourly import

[marconi]

Thinking on the intermittent nature of your charging problem....

The Vesta V27 includes switchable power factor correction under computer control because the generator has two selectable windings depending on the power output..

See para 3.12 and 3.17 of

https://www.mwps.world/wp-content/uploads/2010/09/Vestas-V27-Technical-documentation.pdf

Some HH meters record kVAh as well as kWh and some energy suppliers charge for reactive or apparent power consumption and not just kWh.

Blog: The Easy Guide To kVA Levels / Capacity Allowance - Inenco

Businesses with sites affected by P272 may need to understand how the move to half hourly settlement affects their capacity allowance.

www.inenco.com

See: https://www.edfenergy.com/sites/default/files/b2b-guide_to_reactive_power.pdf

Thinking more on the intermittent nature of the 'spikes' in half-hourly consumption, it would be very helpful to know:

a. the units and amounts ie: kW? kWh or kVAh?
b. how is the data from the HH meter returned - through the internet automatically?
c. does your electricity bill show a charge for kVAh and/or reactive kVArh. I am making a distinction here between kWh - actual power consumed and kVAh - apparent power which is higher and comprises of actual power plus reactive power which is not a net transfer of energy but rather a tooing and froing between the supply and certain types of load such as motors and generators.

 

[Lucien Nunes]

See: https://www.edfenergy.com/sites/default/files/b2b-guide_to_reactive_power.pdf

As an aside that EDF e-guide is pretty rubbish! Its first factual error occurs at the third word and there's a further error before the end of the sentence. It doesn't get much better. Can anybody make sense of this:

Where the first step is 50%, the Local Network Operator does not charge for reactive power for the first 50% of units (kWh). Charges therefore apply when the difference between the total units recorded on the reactive register (kVArh) is less than 50% of the total units consumed (kWh).

I know what it is trying to say, but if I didn't, I'd be more confused than when I started.

 

[marconi]

You point out a typo first.

Second you quibble I think about the use of 'difference'. AP = TP + RP when I was at school so RP =AP - TP - a difference. You know why I have written them in bold. AP is apparent power, TP is true power and RP is reactive power.

On the third point you may be tired. An example calculation was provided. But yes, 'more than' instead of 'less than'.

Suggest you contact the author of it.

 

[Lucien Nunes]

Not wishing to sidetrack the thread, my first point was that KVArh is not a unit of power as implied. The second, yes, this is aimed at non-technical people with no knowledge of the underlying maths who are unlikely to interpret correctly the ambiguous 'total power consumed.' Then, apart from the sign issue, the difference between which two variables specifically; the kVArh reading and what?

They were just three of many quibbles picked at random. I could have complained about the meter that consumes 2.5MWh, the number agreement error between 'most electrical equipment' and 'create', the non-sequitur 'reactive power therefore generates...' etc. More importantly, it does not explain reactive power coherently, nor why the charges it attracts are computed in the way they are, nor differentiates between power factor and efficiency (a common source of confusion.) Power factor supposedly 'indicates how effectively electrical power is being used.' Grr.

 

[marconi]

Suggest you contact the author of it or re-write it for EDF (for a fee).