No abstract

Introduction—The problem of constructing and maintaining in the same region networks of lines for the transmission of power and of intelligence in such a way as to minimize the electrical interference between these two types of facilities is of a complicated nature. One of the controlling factors in determining the severity of any situation may be the effects of currents returning through the Earth. In power‐supply systems, as usually designed and operated, the current in the Earth under normal conditions is quite small, but occasionally short circuits to ground occur which increase this current sometimes to hundreds of amperes. In electrified railways a substantial portion of the propulsion‐current returns to the source through the Earth, and as in power‐supply systems, this earth‐current may be greatly increased by short circuits to ground.

No abstract