XVI. Corona-initiation measurements on polyethylene and rubber cables

IN THE MAIN, cable corona is considered as being due to the presence of minute air voids within the body of the dielectric or adjacent to the inner or outer conductor. That this hypothesis is justified is well established by examination of cables in which corona is known to occur and by the experimental behavior of cables under test; their performance is identical with that of a capacitance-shunted gap in series with another capacitance, the whole being shunted by a large capacitor whose capacitance is equal to that of the cable under test. The gaps and their associated capacitances are basically mi-croscopic circuits whose effects are to be measured by detection circuits capable of responding to macroscopic phenomena.