Selection Criteria For Surge Arresters

The independent power supply for monitoring equipment is mostly AC220V or DC12V/24V system. The maximum continuous operating voltage of the lighting arrester 33kv should be 1.15 times higher than the rated voltage of the power supply. AC220V systems should be equipped with a lightning arrester 20 kv system with 385V voltage protection level, while DC24V systems should use products with 40V protection level. The nominal discharge current of lightning arrester 22kv needs to reach 5kA (8/20μs), and 10kA or higher specifications should be selected in Class C lightning protection areas. The grounding resistance of the monitoring system should be less than 4Ω, and the lightning arrester 24kv system should be connected to the equipotential bonding busbar through a grounding wire not exceeding 0.5 meters. Excessively long grounding leads will generate induced voltage, reducing the protection effect.