The 220,000-volt system of the hydro-electric power commission of Ontario — II

AT the summer convention of the Institute in 1930, Mr. E. T. J. Brandon presented a paper under this same title,¹ describing the design of the initial components of this system, which had then been in operation approximately one and one-half years. At that time, one and one-half circuits, having a combined length of 350 miles, were in service, transmitting approximately 110,000 kw. to a receiving terminal station in the Toronto area of 180,000 kva. capacity. At the present time, the Commission is operating a total of 1,000 miles of single-circuit 220,-000 volt construction, with one receiving terminal of 420,000 kva. rated capacity and is placing into service immediately 45 miles of double-circuit construction and a second receiving terminal of 150,000 kva. capacity. This paper presents a brief history of the development of the system and places on record the experience gained in 8,400 circuit-mile-years of operation of the transmission circuits. Data are presented regarding lightning outages and the behavior of the circuits under sleet and conductor vibration.