Discussion on “single-phase high-tension power transmission”, at Niagara Falls, N. Y., June 28, 1907

In this paper Mr. Young gives a discussion of the relative economy of the different transmission systems. In bygone years, considerable discussion took place on this point, and it was shown that the three-phase system requires only 75 per cent. of the copper of a single-phase system or a four-wire two-phase system, on the basis of equal maximum electrostatic stress. With the change of industrial conditions, such conclusions will have to be revised. When the matter was discussed before, when the statements were correct, because in those early days all electrical circuits were operated as isolated systems without grounded neutral, and in that case the voltage which came into consideration was the voltage from conductor to conductor, across two insulators, and in that case the three-phase system has an advantage of 25 per cent. in copper.