Publication: Electrical World and Engineer
New York, NY, United States
Along the Niagara -Toronto Transmission Line.
SIX hand drawn copper cables, each of 190,000 circular mils cross section, now stretch over a line of steel towers 75 miles long between a terminal station at Niagara Falls and another at Toronto. In a few weeks the two circuits formed by these cables will be delivering energy generated by Niagara water to the electric lighting, power and street car systems of the second city of Canada.
A general description has been given in these columns of the design and construction of this transmission line, which, by reason of its length, the voltage employed, the amount of power to be delivered, and its steel towers, is one of the most notable in the world. Now it is possible to add some details as to the completed line work. Each of the two groups of three conductors on the steel towers forms a three-phase circuit, which is designed to receive current at 60,000 volts from Niagara Falls, and to deliver 12,000 horse-power in Toronto with a loss of 20 per cent in voltage. A loss of 20 per cent in voltage on the line will be incurred at times, and under these conditions the two circuits will deliver about 43,000 horse-power, with a zoo per cent. power factor.
In its 75-mile course the transmission line of steel and copper takes an outline like the string of a well drawn bow, with the ends at Niagara Falls and Toronto, and the center near the western end of Lake Ontario, which is known as Burlington Bay. Along almost its entire length the line traverses the watershed of the lake approximately parallel with its shore, and thus crosses the numerous creeks that flow into it between the Welland Canal and Toronto. The streams of which these creeks are now only feeble remnants, have in past ages cut wide and deep gorges in the high lands that run back from the lake, and in several instances extra long spans have been necessary at such crossings. About seven miles from Niagara Falls the line crosses the Welland Canal on towers that carry the conductors 150 feet above the water, and on these high towers lightning rods are used. Ten miles from the Niagara terminal station the line begins to verge toward the shore of the lake, and reaches the brow of the escarpment after a run of 29.6 miles, at a point a little beyond Grimsby. From this point to the 35th mile the line carries a galvanized steel cable above the copper conductors as a lightning guard wire. This cable is secured at the top of a central extension of the steel tower which holds it seven feet above the nearest copper conductors. Though resting on the steel work of the towers, the guard cable is more effectively grounded at intervals.
By following the narrow neck of land known as Burlington Beach, which separates Burlington Bay from the main body of the lake, the line avoids a course around its extreme west end, and thus saves several miles in length. For purposes of navigation to the city of Hamilton, near the head of the lake, a canal cuts Burlington Beach, and the circuits cross this canal high above the water. On the north shore of Lake Ontario, near Bronte, the line crosses the gorge of Twelve Mile Creek with a span 630 ft. long. The steel towers at the ends of this span are of extra heavy construction, and each tower carries three insulators i