4
Simplified diagram the distribution electricity from power station consumer.5. single-phase 230 supply usually
provided for individual domestic consumers.
11. Loads connected between phases are fed 400 and
those fed between one phase and neutral 230 three-phase 400 V
supply used for supplying small industrial and commercial loads such as
garages, schools and blocks flats.
.
Power
station
25kV
Transformer
132kV to
33kV
Transformer
400kV or
275kV
to 132kV
Light industry
11kV
400V
Local garage
230V
Shops
230V
Houses
Underground distribution 400/230 volt
Underground distribution
230V
Small
offices
Overhead
transmission lines
400kV, 275kV or
132kV
Heavy industry
33kV
Transformer
33kV to
11kV
Local
sub-station
11kV to
400V
FIGURE 11. The final connections are usually simple under-
ground radial feeders 400 V/230 Underground cable distribution is
preferred within city, town village because people find the overhead
distribution, which see rural and remote areas, unsightly. The 400 V/230 derived from the kV/400 sub-station
transformer connecting the secondary winding star shown Fig.Basic Electrical Installation Work
224
Distribution the consumer
The electricity leaves the local sub-station and arrives the consumer’s
main’s intake position. The star point earthed earth electrode sunk into the ground
below the sub-station and from this point taken the fourth conductor,
and the neutral. Also, at
these lower distribution voltages, the cost underground cables not
prohibitive
