Surge Protector (SPD), also known as lightning surge protector or lightning arrester, is an indispensable overvoltage protection device in modern electrical systems. It can quickly conduct and discharge when sudden high voltages such as lightning induction or line operation overvoltage occur, confining the dangerous voltage within a safe range and effectively protecting distribution boxes, distribution cabinets, precision instruments, monitoring equipment, communication base stations and various electrical devices from damage caused by lightning strikes and surge impacts.