EFFECTS OF TORNADO LOADS ON TRANSMISSION-LINES

Of all the populated areas in Canada, southwestern Ontario has experie nced the highest tornado incidence and faces the greatest tornado dama ge. About 1 or 2 tornadoes per 10,000 km(2) can be expected there annu ally. The probability of a tornado strike at a given point is very sma ll but the probability of a transmission line being crossed by a torna do is significant. The purpose of this paper is to review the literatu re related to tornadoes in Ontario and to investigate the effect df to rnado loads on transmission lines. Based on this investigation a desig n basis tornado loading for transmission towers is proposed.