LIGHTNING CURRENT DETECTOR AND THUNDERBOLT FALL POSITION LOCATING DEVICE USING THIS DETECTOR

摘要

PURPOSE:To accurately detect a lightning current with a simple structure by installing a through-type current transformer on an overhead earth-wire where a lightning current flows and specifying the level of the lightning current in accordance with the operation of an arrester where discharge light emission occurs. CONSTITUTION:A through-type current transformer 2 is installed on an overhead earth-wire 1, and resistance 31 and 32 are connected in series between its output terminals. When a current Il flows in the overhead earth-wire 1 by the occurrence of lightning, a voltage corresponding to the current Il is applied to arresters 41 and 42 through the through-type current transformer 2 and resistances 31 and 32. When the current Il exceeds an operation level I1 of the arrester 41 and an operation level I2 of the arrester 42 together, arresters 41 and 42 emit light by discharge. Consequently, the presence or the absence of discharge light of arresters 41 and 42 is detected through optical fibers 5 by photodetectors 81 and 82, and the level of the lightning current is detected in accordance with the operation level of the arrester where discharge light emission occurs.