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Types and working principle of power surge protectors


The power surge protector includes the single-phase power surge protection box, three-phase power surge protection box, single-phase power surge protection module, three-box power surge protection module, and surge protection socket. Power surge protectors are widely used in various distribution stations, power distribution rooms, power distribution cabinets, AC/DC distribution panels, switch boxes, and other important and lightning-prone equipment.
The function of the power SPD is to release the surge current generated by lightning strike and induction into the ground in a very short time (nanosecond), so as to protect the equipment on the line.
According to the working principle, the power surge protection device can be divided into switch surge protection device and voltage limiting surge protection device. The switch-type surge protector is used to protect the power system in zones 0 to 1. The limited-voltage surge protector is used to protect the power system in LPZ1 and subsequent surge zones.
Principle of the power surge protector: The surge protector is connected in parallel to the power cable and connected to the grounding system. Under normal circumstances, the lightning protection device is regarded as a circuit breaker to the ground. When the lightning current intensity (surge) exceeds the action standard of the lightning protection device, the lightning protection device will quickly respond to the ground conduction and discharge the lightning current. After the discharge of lightning current is complete or the surge disappears, the lightning protection device can quickly restore the ground disconnect state.

Because the switch type lightning arrester is mainly composed of discharge gap, pneumatic discharge tube, thyratron and three-terminal bidirectional silicon controlled element, its conduction to the ground is "open and close", once the lightning current intensity exceeds the switch type lightning arrester action standard, the lightning arrester is instantaneous large degree of discharge lightning current. The switching lightning protection device has the advantage of strong discharge ability, and can channel the simulated lightning impulse current of 10/350μs.