lightning arrester

Dear friend,

You should first do a lightning risk assessment as per IEC 61024 or BS 6651. Current value during lightning depends on the geographical location of lightning protection system and selected protection level. The peak value may be 200kA for protection level I, 150kA for level II and 100kA for level III and IV as per IEC 61024-1-1.

Depends upon the application. The arresters with greatest exposure to lightning are distribution class. Choose normal (65 kA) or heavy duty (100 kA). Next would be intermediate class followed by station class.

Intermediate and station class generally have larger blocks with higher energy absorption capability because they are designed primarily for the higher energies associated with switching and other system overvoltage surges.

Although lightning surge currents may be high, they are of very short duration (typically less than 100 microseconds; including restrikes) so the resultant discharge energy is significantly lower. (To put that time in perspective, the time to first half-cycle crest of a 60 Hz current or voltage wave is 4,167 microseconds).

Statistically, at least in the U.S., over 90% of lightning strokes are of negative polarity with a mean stroke current of around 35 kA. Although rarer, positive polarity strokes tend to be of higher magnitude. As noted, the majority of lightning strokes are high current short duration but low current long duration strokes tend to cause more damage.

Hi,

In general LA's are designed for Highvolatge as well the Current in kA. The standard rating used in India as per the pevailing norms are as follows:

For 220 kV Substation 196 kV, 10 kA of current, 132/110 kV, 96 kV, 10 kA, 33 kV, 30 kV, 10 kA, 11 kV, 9 kV, 10 kA. The maximum 10 kA Ampres is the current flow during Lighning Action which will be earthed.

N.Suresh

In addition for 400 kV, 396 kV, 10 kA is alos avaialble.

N.Suresh

You might be able to arrest it, but how are you going to keep it in jail?

we have look at many products for our app. Cutler hammer etc. The best product that we have found is Canadian made product called Clean Volt Rated IEEE rated C62.11 THis is not TVSS and has actually saved on power consumption as well Look at www.mimcv.com