Posted by Solar Flare on February 16, 2006, 8:02 am
RkVAh meters are used to integrate kVA demand from.
rkVAh is not a billable quantity any place I have ever
In Ontario demand is billed at kW or 90% of the kVA
when lagging. Leading kVA was never discussed. I
believe it has been or will be discussed shortly and
Posted by Jeff Thies on February 17, 2006, 1:01 am
Solar Flare wrote:
Where does the leading kVA come from? I'm unsure where lighting loads
fall but I would think typical ballasts would put them on the lagging side.
What about switching power supplies. I would think the non linear draw
could put that PF almost anywhere and I know that data centers can draw
a lot of power!
Posted by Solar Flare on February 16, 2006, 12:05 pm
The leading pf comes from pf correction
techniques...static or rotating capacitors. Elevators
going down will do it naturally. I am not sure about
switching power supplies. There are many different
styles of them and I am out of date on that technology.
where lighting loads
them on the lagging side.
the non linear draw
data centers can draw
Posted by daestrom on February 17, 2006, 6:29 pm
Actually, 'conventional' flourescent lighting can go either way. While the
ballast is inductive, the lamp itself is capacitive. So depending how well
the two are matched, it could be slightly leading, or lagging.
And as Solar pointed out, pf correction capacitors can cause a leading pf as
well. This can happen when the capacitors are sized for some 'full load'
situation, and the loads are running at only partial load. The pf
correction caps may not be controllable in 'steps' to accomodate changes in
capacitance needed for changing load conditions. So design for a 'happy
medium' and accept slightly leading pf at times.