Electrical Power the National Grid
Electricity generated large modern Power Stations 25kV (25,000
volts). This would not possible if
a d. supply was generated.
The ease and efficiency changing the voltage levels only possible
because generate a.
. This network
of overhead conductors suspended transmission towers which link
together the Power Stations and the millions users electricity.c.19 shows simplified diagram electricity distribution.
Raising the voltage these very high values reduces the losses the
transmission network. then transformed 132kV 270kV for transmission to
other parts the country the National Grid network. 66kV 33kV are used for secondary transmission
lines and then these high voltages are reduced 11kV local sub-stations
for distribution end users such factories, shops and houses 400V
and 230V.Basic scientific concepts electrotechnology
117
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 5. Very high voltages for
transmission, lower voltages for safe end use.
Figure 5.c.19
Simplified diagram the distribution electricity from power station consumer. supply. Transformers are then used change
the voltage levels those which are appropriate
