Lightning Disturbances on Distribution Lines

[mjonie]

Hie Guys

Good work, feels good to come onboard.

Please help. we are experiencing lots of disturbances on our 33kv and 6.6kv overhead distribution lines due to lightning. We have surge arrestors installed on strain poles and all the major equipment, transformers etc. It’s an open pit mining set up in Southern Africa and the rains have just begun. I was wondering whether there is something that can be done, protection wise, to reduce the number of trips. Also I have head somewhere about ZnO Surge arrestors please shed more light

 

[Marmite]

I don't think there is much you can do to reduce the number of lightning trips per se. What you can do is mitigate the effects of the trip by minimising the likelyhood of permanent damage to plant and equipment (triggered spark gaps, duplex gaps, surge arrestors etc) and minimising the effect of the trip by rapidly isolating any damaged equipment (fuses, autosectionalisers, circuit breakers)followed by rapid reclosure to restore supplies.
Which of these measures do you want information on?
Regards
Marmite

 

[mjonie]

Thanks Marmite
Please shed more light on the triggered spark gaps, and duplex gaps. Also how much difference do arrestors on the line make and do we really need them like after every 10 poles looking from a cost point of view or should we limit them to sensitive equipment only?