Lightning-Induced Surges in Paired Telephone Subscriber Cable in Japan

This paper presents measured and calculated data that can be used as a basis for designing and protecting telecommunication equipment against lightning-induced surges in Japan. The paper examines the variations in geographic and environmental conditions in different parts of Japan (e.g., thunderstorm days, summer versus winter lightning, ground (soil) conductivity) and describes measured variations in lightning-induced surge characteristics in subscriber-paired cables due to differences in geographic conditions and cable conditions (e.g., cable type, buried versus aerial cable, cable length, cable height, terminal conditions, main versus branch cable). Measured lightning characteristics (e.g., front time, time-to-half-value) are compared for various measurement locations (e.g., subscriber end for subscriber cable, telephone office end for subscriber cable, telephone office end for toll cable). A general set of equations is empirically derived that predicts lightning-induced surgevoltage occurrences, front time, and time-to-half-value distributions.