Edwin Pawlowski ) said...
Power correction factor is different. It can be done inside, after the meter
and is perfectly legal. I don't know if it is a viable option for
residential, but for industrial use, there are savings to be had.
It is not a viable issue for residential customers as they are charged
for actual power used (kWh).
Industrial users tend to have heavy motor loads that create a lagging
power factor. With a power factor of 1, kVA is equal to kW, so the
facilities needed to deliver 1000 kWh only has to be able to carry
1000 kVAh, and the losses due to heating that equipment is at its minimum.
If the customer's power factor was 0.5, then the equiment need to deliver
that same 1000 kWh needs to support 2000 kVAh! This means twice the current
for the same power. Since heat losses are proportional to the SQUARE of the
current, you lose FOUR times the power just heating the infrastructure.
Industrial customers are charged for kVAh if they exceed a certain
threshold, so it is in their interest to keep the power factor close to
1. They maintian large capacitor banks to do so.
Residential customers do not generally run at a lagging power factor. In
fact, it is likely they have a slightly LEADING power factor resulting
from the combined capacitance of all the wiring in the home. I know this
from when I used to work as a watchman in a plastics moulding plant. During
the weekends when the plant was shut down, it was not unusual for the
power factor to be about 0.9 on the leadinig side (there was a PF meter at
the service entrance).
As the plant was started up and various motorized equipment was started,
the power factor would shift towards the lagging side and capacitor banks
would be switched in.
--
Calvin Henry-Cotnam
"I really think Canada should get over to Iraq as quickly as possible"
- Paul Martin - April 30, 2003
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