Newsgroups: rec.arts.theatre.stagecraft
Subject: Re: Interesting Electrical Questions
References:     <[email protected]>
"Ben"  writes:

> I've never really figured out how large installations are billed. Is it just
> an estimate, or are threre actually meters in the substations (e.g in
> factories, universities etc)?

Large installation have meters, in a way or another.
A large factory for example typically has more accurate
meters than normal household and such. Those large
installation meters generally measure the real part
and imaginary part of power (where normal residential
meters generaly measure only real consumed power).
Because also the imaginary part of power is measured,
the power factor correction makes financially sense
in large installations. In some large installations
the power meters aver very accurate so that they 
record all the time consumed power and keep track of time,
because the price of power can vary on different times
if you get such agreement (you get very cheap power
when there is lots of excess capacity, but at high
consumption peak times the power fecomes very expensive
for this kind of consumers)..

-- 
Tomi Engdahl (http://www.iki.fi/then/)
Take a look at my electronics web links and documents at 
http://www.epanorama.net/