1.  Power plants
are usually far
from
communities,
thus long lines
are needed to
transmit power
into homes

2.  The resistance of
such lines are
enormous to
start with
because of their
length
L
R
A

3.  Transmission
losses are
less if power
is conducted
at low
current
Ploss  I
2
R

4.  In order to transmit at low
current, power must be drawn
from substations at high
voltage
Ps  IV

5.  For safe
consumption,
however, the
voltage must be
brought down
before being
distributed into
homes

6.  Thus, the necessity for step-up and
step-down transformers