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£1,500,000 INVESTED IN PLANT.
Much has been heard recently regarding tho important part that electricity is going to take in the life and work of the com- munity, so it may be of interest to review thc electrical development that has taken place in Melbourne since 1894, the year that the City Council installed its power house at Spencer street, for the purpose of supplying electricity for street lighting.
Thc council's venture was on a very modest plan, for the total capacity of the first plant was but 1,200 horse-power. In 1897 the plant was extended so as to en- able a supply to be made available for private consumers. From that time on
there has been a steady and continuous development, as will be seen from the fol- lowing figures:- In 1904 4,000,000 units for light, heat, and power were sold; five years later the sales had doubled; in 1914 17,000,000 units were sold; and by the end of the next period of five years the figure had risen to 34,000,000; and in 1922 it had not quite doubled, as it had done in thc three previous five year periods, but still the increase in output was again very large, for that year the council sold 53,800,000 units. With this ever-increasing output it had, of course, to make frequent additions
to the generating plant, and to increase the reticulation system. In carrying this out thc council has incurred a capital expendi- ture of over £1,500,000.
Up to 1912 tbe private supply was given
from direct current generators driven by high speed engines, but owing to increasing demands it was then decided to instal large turbine-driven alternators, furnishing a 50 cycle 3 phase 6,600 volt system, which has now become a recognised standard. The system was extended by means of under- ground cables to various sub-stations throughout the city, and transformed ns required to pressures of 400 and 230 volts.
The rotary converters at Little Queen st. take alternating current at a
pressure of 500 volts, and convert it into direct current.
suitable for motive power and lighting. At Heffernan lane a large sub-station was erected, and a rotary converter plant was installed, for the purpose of providing a direct current supply. Similar rotary plant was also installed at Spencer street, superseding the small engine-driven sets. In 1020 it was found necessary to provide further large extensions of plant, and a new switch house was erected at Spencer street. In these premises is installed large modern high-power switch gear, and ?? this point radiates a system of under-
ground feeders connecting with 33 outlying
SUB-STATION AT LONSDALE ST.
At this station current is received from Newport at a pressure of 20,000 volts, lt is "stepped-down" by trans formers to a pressure of 6,600 volts, and it is then distributed to smaller sub-stations, where it is again stepped
down to 460 volts.
sub-stations. An additional rotary con- verter sub-station waa also found necessary to meet the growth in the direct current area, and for this purpose a new building was erected in Little Queen st., and two 2,000 kilowatt converters have recently been installed. This station bas been de- signed for 12,000 kilowatt capacity (about 15,000 horse-power), and its equipment re- presents the latest practice.
In the power house the main generating machinery comprises a number of units
SPENCER ST, POWER STATION.
A general view of the engine-room at the Spencer st power station. The total capacity of the plant is equal to
nearly 35,000-horse power.
aggregating 30,000-horse power. Each unit is a self-contained power plant, and can be started up and connected to the sys- tem in a few minutes. Water for condens- ing purposes is taken from and returned to the Yarra by means of low-level con- crete ducts. Four centrifugal pumps, each with a capacity of 500,000 gallons per hour, are employed for this purpose. Adjacent to the machine-room is the boiler-room, where is installed 20 water-tube boilers
fitted with automatic stokers. These
boilers supply steam at a pressure of 160lb. per square inch and a temperature of 520deg. Fah.
Coal is delivered into overhead bunkers
having a capacity of 2,000 tons, by means of a bucket conveyor capable of handling 35 tons per hour. From the bunkers the coal gravitates through weighing machines
This gives a view of the three-phase transformers and the switchboard at the switch house, Little Queen st
to the stokers, the whole process being designed to reduce manual labour to a minimum. To carry off -waste gases from a score of boiler furnaces two smoke stacks are provided. They are 175ft. in height, and have an average internal diameter of
The 6,600-volt switchgear is housed with-
in concrete cubicles, and is operated elec trically by a remote control system; this not only simplifies operation, but removes the operators from any possible danger or contact with "live" parts. These switches , are also adjusted to operate automatically in the event of any condition arising that would endanger the machinery.
During the progress of the Great War the possibility of obtaining new machinery created a difficult situation, which was ultimately met by the City Council enter - ing into an arrangement to purchase energy from thc Victorian Railways de-
partment's power-house nt Newport, and a supply from this source was commenced at the beginning of 1922. But the demand for power is continuously increasing; there- fore, in view of the development of the Morwell project, the council will in future obtain its additional supplies of energy in bulk from that source, and will, no doubt, become one of the largest customers of the Morwell undertaking.
The council's experts consider that the Melbourne consumer gets his power at a
moderate figure, all things considered, and they supply data to prove their case. Thus at Bradford, which has about, the same electric consumption as Melbourne, the consumer pays 1.78d. per. unit (including traction); against 1.905d.. which the City Council receives. If the Bradford supply is slightly cheaper than Melbourne, in a number of other cases the Melbourne figure of l.905d. shows in a very favourable light.
For instance, in,Belfast, the average unit cost is 2.66d; in Bristol it is 2.12d.; in
Salford it is 2.1Sd.; and in the city of London it is no less than 3.96d., or more than double as much as it is in Melbourne, though wages here are much higher, and
coal is dearer.
In connection with the electric supply the council has 444 employees, and the annual wages bill is £115,000. The coal
consumed is 1,000 tons a week, The maxi- mum demand for current is now about equal to the full maximum capacity (34,840 horse power) of the generating plant it the Spencer-street power-house, so that if it was not possible to draw on Newport for current, and if Morwell were not a prospective supplier, the council would
have come to the end of its electrical re- sources for it would not be practicable to make any considerable additions to the Spencer street plant.