For best performance of the lightning arrestors it is utmost essential that the arrestors may be installed and maintained properly. Apart from this it is also necessary to maintain the records and to check healthiness of the arrestors.
Quarterly Maintenance :
| Sr. No. |
Subject |
| 50-51 Q |
Check for cracks and damages of base. |
| 50-02 Q |
Check for setting or shifting of base or support, tighten bolts and nuts. |
| 50-03 Q |
Check porcelain for cracks. Repair after taking shutdowns, if any chipping is noticed. |
| 50-04 Q |
Discharge counters should be checked periodically to ensure that the same are properly functioning. In the event of discharge counter becoming defective the same should be replaced so that the number of operations of arrestor is known, which is necessary to make any analysis as to the reason for failure. |
| 50-05 Q |
Check earthing of lightning arrestor. |
Yearly Maintenance :
| Sr. No. |
Subject |
| 50-06 Y |
Clean the porcelain for dust etc. particularly in contaminated areas. |
| 50-07 Y |
Tighten the line and around connections. Check earthing for corrosion or damage below ground lines connection. |
| 50-08 Y |
Measure the resistance of ground connection, station class arrestors should not be provided with ground of value not exceeding 5 ohms. |
| 50-09 Y |
Check whether the jumpers connected with L.A.'s are of correct length to avoid excessive strain on the top of arrestor stack. |
How to Check Health of Arrestor :
Keeping proper record of the discharge counter reading and the leakage current in mA is of vital importance. Initial leakage current reading should be taken at the time of commissioning and if reading increases 3 times the original value it should be kept under observations and taken out for inspection at convenience. The matter should be referred to the manufacturer in case reading increases 5 times the original, the arrestor should be taken out of service as soon as possible. Before removing the L.A. from service be sure that counter is reading correctly. Reading should be taken under dry and clean conditions.
The life expectancy of the L. A; is 20 operations. No. of operations should be checked by taking discharge counter reading periodically. In case of operations exceeds 20, it should be replaced.