The UZN Protection Device is designed to safeguard overhead AC power lines with voltages ranging from 6 to 35 kV against atmospheric lightning overvoltages.

Design and Operating Principle:
The UZN consists of a specially designed nonlinear surge arrester (NSA) and a spark gap (SG) between the phase conductor and the NSA. The NSA is a protective device composed of a single column of varistors connected in series and encased in a hermetically sealed polymer housing.

When lightning overvoltage occurs, the spark gap breaks down, allowing the overvoltage energy to be diverted through the NSA to the ground, thereby preventing damage to the equipment.