Lightning Surges in Paired Telephone Cable Facilities

Abstract

The problem of protecting apparatus against lightning surges from connected transmission facilities has become more complex with the use of solid state devices in apparatus design. Consideration of the protection requirements for such apparatus has indicated that existing information concerning the incidence and characteristics of lightning surges is insufficient to develop optimum protection measures. A recently completed field investigation provides additional information in this specific area. The results of this field investigation and supplemental laboratory surge tests indicate that, in well‐shielded underground cable pairs, electrical surges do not exceed approximately 90 volts peak, and that transistorized apparatus capable of withstanding such surge amplitudes needs no further protection. In aerial and buried cable, however, transistorized apparatus requires protection up to the full sparkover potential of 3‐mil protector gaps, i.e., to about 600 volts peak. A firm basis for testing and evaluating transistorized apparatus from the lightning surge voltage standpoint is presented.

Semiconductor devices in hostile electrical environments

“…4 and 5 show the distribution of surge rise and fall times noted in these and similar cables, 6 and in cables having lead sheaths. 7 With knowledge of the peak value (F) of the surge, the fall-time to half value T 2 and the impedance Z (ohms) of the longitudinal circuit along which it is propagated, the approximate energy W may be calculated from the relation W^V 2 T 2 1.38Z…”

Lightning Effect on Copper and Optical Fiber (FTTN) Access Networks of Telecommunication Systems

“…Thirdly when lightning strikes the ground, its potential rises and, as a result, ground potential of the appliances may become high. A lot of information has been collected on lightning effects on telecommunication systems during last few decades [3][4][5].…”