Proper lightning arrester application improves distribution system reliability

For distribution system overvoltage protection design, all necessary sources of contribution to net residual voltage may not be considered, overstating the actual margins of protection available. This includes total lead length and current impulse rate-of-rise. Underground circuits are subject to voltage doubling. If all sources of residual voltage are not considered, the calculated margin will be overstated as well. Recommendations for improved protection are included, and various examples of protection for an 11 kV, 95 kV basic impulse insulation level system are included