lightning arrester

[mel127]

Greetings,
The past two occasions we encountered two blown out lightning arresters(due to old age).The arrester was made by Westinghouse , 30 KV application , type SV Autovalve with style no. 1594748. What do you recommend to replace this obsolete arresters? And also can we trace what year did this arresters was manufactured and made based on the style no? This will be a good justification to replace this arresters.
Thanks in advance.

 

[wbd]

I think you find that most LA's now are MOV type. We typically use Cooper Power Systems LA's. You will want to talk to your local representative.

As far as age and justification, there is a saying in the US utility industry, "if it's brown, take it down", meaning if it is made of brown porcelin, it should be replaced.

 

[RRaghunath]

Other points you may like to check up,
1) Is the 33kV system Effectively earthed, if not, you may have to go in for 33kV Arresters while replacing the existing ones
2) Did the LAs fail during lightning, if so, the discharge capability of the existing LAs could be the issue. This is better with current LAs.

In any case, while considering replacement, I would prefer MOV type LAs with MCOV of 33kV atleast and discharge capability of 10kA.

 

[mel127]

Raghun,
The LA's failed in a clear sunny day. The area where I come from lighting and rains is seldom experienced. This LA's triggered twice in a span of 2 months. MOV type arresters are what we're using in distribution. This porcelain arresters was installed long time around 60's.As far as earthing is concerned?Yes they are properly earthed.