Page 22 - Sphere No.6 (Jun 2002)

C O V E R S T O R Y
BRINGING IT HOME
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9a
9b
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1. Ocean-going vessels deliver
coal to the Power Station’s
dockside. It is conveyed to
the junction tower then on
to the coal storage areas or
fed to the boiler bunkers via
a duplicate conveyor system.
2. Coal is stored in one
storage yard with a total
capacity to meet six weeks’
consumption.
3. Each generating unit stores
coal in five coalbunkers.The
coal is fed to the boilers,
which produce steam at tem-
peratures between 541°C and
569°C.
4. Steam passes through the
turbine, which converts the
energy to mechanical energy
for driving the generator.
5. The generators produce
electricity at 12.5kV to 22kV.
6. Transformers step up these
voltages to 275kV.
7. All the electrical power pass-
es through the Lamma 275kV
Switching Station.
8. Electricity is transmitted to
Hong Kong Island via two
separate 275kV submarine
cable routes across the East
Lamma Channel.
9.The power arrives at 20
switching stations (9a) and 25
zone substations (9b), which
are equipped with remote
control and monitoring
facilities. In the major load
centres, large-capacity
transformers step down the
voltage to 11kV before distri-
bution. Electricity is then dis-
tributed to 3,444 customer
substations (9c), and further
stepped down to 380/220V
for final distribution.
10. The transmission and dis-
tribution network is remotely
monitored and controlled at
the System Control Centre.
11. Rigorous tests are carried
out on all meters before being
installed in customer premises.
12. Power is available to all at
the flick of a switch.
HEIDI MA (1)
SPHERE
1220
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9b
9c 9c 9c
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