Based on working principle, surge protectors can be divided into voltage switch type, voltage limiting type and combined type.
(1) Voltage switch surge protector. High impedance occurs when there is no transient overvoltage. Once it responds to the lightning transient overvoltage, its impedance will suddenly change to a low impedance, allowing the lightning current to pass. It is also known as a "short-circuit switch surge protector".
(2) Low voltage protection equipment. High impedance occurs when there is no transient overvoltage. However, the impedance will continue to decrease with the increase of the surge current and voltage. The current and voltage are strongly nonlinear. Sometimes, it is also referred to as "clamp surge protectors".
(3) Combined surge protectors. It is a combination of components from the voltage switch surge protector and the voltage limiting surge protector. It can be displayed as a voltage switch or a voltage limiting or both.
Based on uses, surge protectors can be divided into power line surge protectors and signal line surge protectors.
(1) Power line surge protectors
The energy of the lightning strike is very huge under a thunderstorm. The power line surge protector can gradually release the lightning strike energy to the ground by grading discharge to avoid casualties and property losses.
(2) Signal line surge protectors
The signal line surge protector is a signal lightning arrester. It is installed in the signal transmission line, which is generally at the front end of the equipment. It is used to protect subsequent equipment and prevent lightning waves from flooding into the signal line to damage the equipment.