Publication: Western Electrician
Chicago, IL, United States
Electric Power Transmission.
BY CHAS. F. SCOTT,
Consulting engineer, Westinghouse Electric and Manufacturing Company.
TWENTY years is in most things a short interval, but in electric transmission of power it is an epoch.
The long-distance transmission of power, as commonly practiced today, was unknown twenty years ago. Some of its fundamental elements had not been discovered, and apparatus and methods which have been in common use for many years were yet to be invented and deevloped [sic] developed.
Practically all transmission today is by the alternating-current three-phase system. Twenty years ago the first alternating-current central station in this country had been in operation but a few months. The introduction of the alternating current was encountering the most strenuous opposition, by technical argument, by commercial antagonism and by attempted legal prohibition. There was no commercial alternating-current motor. It was not until May, 1888, that the Tesla patents on polyphase apparatus and transmission were issued and published. Transformers rarely exceeded two kilowatts in capacity and 1,000 volts in pressure. Insulators and lightning arresters had hardly become clearly differentiated from their telegraphic predecessors, from which they were evolved. Even the direct-current stationary motor was a commercial novelty, and all the electric railway systems in the country aggregated a length of track which could be traversed at present speeds in less than an hour.
BEGINNING OF THE NIAGARA DEVELOPMENT.
It is less than twenty years ago that an international technical commission was formed to determine the methods to be adopted by the Niagara Falls Power Company. It was not until 1893, during the World's Fair at Chicago, that final action was taken 'against the sentiment in favor of direct current by the formal decision to use polyphase alternating current.
At that time commercial frequencies were shifting from 133 cycles to 60 cycles. It was necessary to determine the frequency for the Niagara circuits. It was believed that much of the power would pass through large induction and synchronous motors, or synchronous converters, although such apparatus was more apt to be found in experimental testing rooms or in exhibits than in service. There was very little experience upon which to base the bold recommendation of a low frequency for so large an undertaking. The turbine speed had been fixed at 250 revolutions per minute. The power company's advisers proposed that the generator have eight field poles, giving 16 2-3 cycles (2,000 alternations); the Westinghouse Company recommended 16 poles and 33 1/3 cycles (4,000 alternations). The only possible intermediate course was finally chosen — 12 poles and 23 cycles (3,000 alternations).
POMONA AND TELLURIDE PL