As the term “central-station” associates itself with some pretentious
building, such as a railway terminus, it may be advisable to remark
that the similarity is only in the words, and that central-station is
an abbreviation of central generating station, or building designed to
contain the plant for the public supply of electricity. In the early
days of electric lighting the transmission of electricity to a distance
was considered an impossibility; we find the late Sir William Siemens,
in his Presidential Address at the Society of Arts on the occasion of
the opening of the session in 1882, stating “that a quarter of a mile
in every direction from the lighting station was the area which would
be as much as could be economically worked;” and, in order to tap the
most paying district, it was proposed to establish a station in the
most central spot. Sir William Siemens suggested the utilisation of
the public squares, which could be excavated to a depth of twenty-five
feet, and then arched over to the existing ground level, and in this
covered space the engines, boilers, and dynamos were to be fixed;
the only erection above the surface was the chimney, which was to be
of ornamental design and combined with the ventilating arrangements
of the subterranean chamber. The great inventor, who so ably filled
the presidential chair at the meeting where these words were spoken,
would be astonished to find that in London one electric lighting
company has already erected seventy miles of overhead wire, and that
customers are supplied miles away from the so-called central-station.
The changed position of electricity is due to the introduction of the
transformer by Goulard, who showed, at the Turin Exhibition of 1884,
that a high-tension current could be transformed into a low-tension
working current of safe potential, fifty miles away from the generator,
in a successful and economical manner, and that the generating station
might, therefore, be located outside the area to be lighted. In large
cities this is a great advantage, the value of land often precluding
the erection of a big station in the working area; for this reason
small stations are often arranged in basements, under a large building,
which are, as a rule, specially designed. This plan is somewhat similar
to that adopted in the United States, where it is not unusual to
find a successful installation in a basement and sub-basement, the
general arrangement being of similar character to the engine-room of a
steamship.
A station is being erected in Philadelphia on a ground space of 72
feet × 100 feet, which is to supply 60,000 lights; the building is
six-storied, the dynamos are on the first floor, the boilers on third,
the coal stores on fourth, and the offices on the fifth.
The term “block station” is also used in the United States and in
Germany, and is applied to an installation which lights a group of
buildings or block without crossing any streets, and consequently
without having any wayleave or permission from local authorities.