Shock from lightning arrester

[appunni]

Sir,
In our one substation, we get electrical shock from the portion of the lightning arrester where the counter is connected from the lower side of the lightning arrester. The lightning arrester is connected in one 66kv line incoming side to the yard. The details of the lightning arrester is as given below:
Make: OBLUM ELECTRICAl INDUSTRIES LIMITED, HYDERABAD,INDIA.
Rated voltage: 60KV
Discharging current: 10KA
Rated frequency: 50HZ
Pressure Release Class: 40KA
Long Discharging Class: 3
Model: ZAO - 60 - SM
Type: METOVAR
MCOV: 48KV
Year: 1992

I request to advice me about what are the checks to be carried out at site in detail.
Thanks
with regards,
appunni

 

[ERaySir]

Sounds like your ground is not connected properly or is corroded. Your step and touch potential should be no more than 70 volts. Do not disconnect the ground lead. The frame should be bonded as well. I am not familiar with you model of LA.

Best Regards


Ray Micallef, P. Eng.
Power Generation/Utility Industry

 

[aishu]

Follow IEEE-80 recommendations for surge arrester grounding