1. Switch type: Its working principle is to present high impedance when there is no instantaneous overvoltage, but once it responds to the lightning transient overvoltage, its impedance suddenly changes to a low value, allowing lightning current to pass. When used as such devices, the devices include: discharge gap, gas discharge tube, thyristor, etc.
2. Voltage-limiting type: Its working principle is high-impedance when there is no instantaneous overvoltage, but its impedance will continue to decrease with the increase of surge current and voltage, and its current-voltage characteristics are strongly nonlinear. The devices used for such devices are: zinc oxide, varistors, suppressor diodes, avalanche diodes, etc.
3. Shunt type or choke type
Shunt type: It is connected in parallel with the protected equipment, which presents a low impedance to the lightning pulse, and presents a high impedance to the normal operating frequency.
Choke type: In series with the protected equipment, it presents high impedance to lightning pulses, and presents low impedance to normal operating frequencies.
The devices used as this kind of lightning protection device include: choke coil, high-pass filter, low-pass filter, 1/4 wavelength short-circuit device and so on.
Surge protector is an electronic device that provides safety protection for various electronic equipment, instruments, and communication lines. When a spike current or voltage is suddenly generated in the electrical circuit or communication circuit due to external interference, the surge protector can conduct and shunt in a very short time, so as to prevent the surge from damaging other equipment in the circuit.
The purpose is to further limit the value of the residual surge voltage passing through the first-stage lightning arrester to 1500-2000V, and implement equipotential connection for LPZ1-LPZ2.
The power surge protector output from the distribution cabinet line should be a voltage-limiting power surge protector as the second level of protection, and its lightning current capacity should not be less than 20KA, and should be installed in the substation that supplies power to important or sensitive electrical equipment. Road distribution office. These power surge protectors can better absorb the residual surge energy that has passed through the surge protector discharger at the user's power supply entrance, and have an excellent suppression effect on transient overvoltages.
The purpose is to protect the equipment by reducing the value of the residual surge voltage to within 1000V, so that the surge energy will not damage the equipment.
The power surge protector installed at the incoming end of the AC power supply of electronic information equipment should be a series voltage-limiting power surge protector as the third level of protection, and its lightning current capacity should not be less than 10KA.
A built-in power surge protector can be used in the internal power supply of the electrical equipment to completely eliminate the tiny transient overvoltage. The power surge protector used here requires a maximum impact capacity of 20KA or less per phase, and the required limit voltage should be less than 1000V. For some particularly important or particularly sensitive electronic equipment, it is necessary to have the third level of protection, and it can also protect the electrical equipment from the transient overvoltage generated inside the system.