The character of surge and current
Surge: Products containing surge resistors can effectively absorb bursts of massive energy to protect connected devices from damage
Current: The rapid discharge process produces strong lightning accompanied by a loud sound; when lightning occurs, electric charges are usually generated, the bottom layer is negative electricity, the top layer is positive electricity, and the positive charge is also generated on the ground, which moves with the clouds like a shadow. Positive and negative charges attract each other, but the air is not a good conductor.
What is a lighting surge test?
The lightning surge test is a surge (shock) immunity test, which simulates the pulse interference caused by lightning coupling, or the start and stops of high-power equipment, power supply failure, etc., to test the power protection device of the product to absorb the surge The ability of the pulse, or the pulse interference generated by the start and stops of high-power equipment, power supply failure, etc., tests the ability of the product's power protection device to absorb surge pulses.
1). Causes of surges
Switching transients in the power system.
a ) Major power system switching nuisances, e.g. switching of capacitor banks.
b ) Smaller local switching movements or load changes in the distribution system.
c) resonance phenomena associated with switching devices (e.g. thyristors).
d) various system faults, e.g. short-circuit and arcing faults of equipment combinations to the earth system
2). Lightning transient
a) Direct lightning, which strikes the external (outdoor) circuit, and the injected large current flows through the grounding resistance or external circuit impedance to generate voltage;
b) Indirect lightning (that is, the electromagnetic field generated by the lightning strike between or in the cloud layer or the lightning strike on nearby objects), the induced voltage and current generated on the internal and external conductors of the building;
C) A nearby lightning current discharging directly to the earth, which induces a voltage when it couples to the common earth path of the combined earthing system of the equipment. When a lightning protection device operates, voltage and current may change rapidly and may couple into internal circuits.
The reasons lightning strikes the surge.
1. Inductive accumulation, when lightning discharges, it will be induced on nearby power grid lines and power equipment, instantly generating high-voltage peak voltage and surge current impact, and then transmitted to the power terminal through the line；
2. The start and stop of large motors, the use of frequency conversion equipment, and inductive loads on the same line as the lamps are installed will cause the instability of the grid voltage；
3. Circuit aging and line faults will generate surge signals inside the power grid；
4. Input the surge peak generated by AC high and low voltage switching；
