Tests on 22-Kv. and 4-Kv. Lightning Arresters

The development, within recent years of high-voltage rectifying tubes has made possible the construction of an apparatus which may be used to produce very high-voltage surges of steep wave front, believed to be comparable in potential and capacity to surges caused by lightning discharges taking place near transmission lines. With such an apparatus it has become possible to conduct tests on lightning arresters which show clearly the kind of performance these arresters are giving in service. The Duquesne Light Company has had on its system a great number of lightning arresters of the horn gap and series resistance type. The number of failures on installations these arresters were intended to protect and the number of failures on the arresters themselves have led the engineers of this company to go rather deeply into the lightning-arrester question and into the problem of learning, before an arrester is installed, just what degree of protection it is likely to afford. To get the information desired it was found necessary to make a series of tests on the various arresters now in the market. In making these tests arbitrary requirements were set up as being necessary in an arrester for satisfactory operation on this system. These requirements were as follows: 1??High speed of discharge 2??Ability to break down dynamic current 3??Ability to operate repeatedly The protective value of arresters meeting these requirements was felt to be proportional to the discharge capacities of the arresters.