Purpose of surge testing

>  Simulate lightning interference, mainly indirect lightning, such as:

   1）Lightning hits the outdoor line, there is a large amount of current flow into the external circuit or ground resistance, resulting in interference voltage;

    2）Voltage or current induced by an indirect lightning strike on a wire;

   3）Lightning strikes a nearby object, creating an electromagnetic field around it. When an outdoor circuit passes through the electromagnetic field, a voltage or current is induced on the circuit.

    4）Lightning strikes the ground nearby, which introduces interference when the ground current passes through the common grounding system.

>  Transient interference during state switching simulation, such as:

    1）Interference during switching of main power system;

   2）In the same grid, there are some larger switches near the equipment to form interference when jumping;

    3）Switching thyristor equipment with resonant circuits;

   4）Systemic faults, such as short-circuit or flaring faults in the grounding network or between grounding systems.

Purpose of SURGE TESTING - TO establish a common standard for evaluating the resistance of electrical and electronic equipment to surge interference by means of simulation testing. Systemic faults, such as short-circuit or flaring faults in the grounding network or between grounding systems.

A test device that simulates a surge

According to the IEC61000-4-5 standard, it should be able to simulate the surge test on the power line and the communication line respectively. Because the impedance on the line is not the same, the wave form of the surge on the two lines is not the same, and needs to be simulated separately.

一、For the power supply line test, 1.2/50us combined wave generator is used. The basic line and corresponding voltage surge test waveforms are as follows:

The 1.2/50US waveform is the open-circuit voltage waveform; The 8/20US waveform is the short circuit current waveform; In addition to having the ability to generate the waveforms shown in the figure above, the combinatorial wave generator shall also have the following basic performance requirements:

>  Open circuit output voltage (peak) : 0.5 ~ 4KV;

>  Short circuit output current (peak) : 0.25 ~ 2KA;

>  Generator internal resistance: 2 ω (additional resistance 10 or 40 ω, in order to form 12 ω and 42 ω generator internal resistance);

>  Surge output polarity: positive/negative;

>  Surge shift range: 0° ~ 360°;

>  Maximum repetition rate: at least once per minute.

二、For the communication line test, the 10/700US combined wave generator is used. The basic line and corresponding voltage surge waveform are as follows:

The 10/700US waveform is the open-circuit voltage waveform; 5/320US waveform is short circuit current waveform; In addition to having the ability to generate the waveforms shown in the figure above, the combinatorial wave generator shall also have the following basic performance requirements:

>  Open circuit output voltage (peak) : 0.5 ~ 4KV;

>  Dynamic internal resistance:40Ω；

>  The output polarity：Positive/negative；

Test Precautions

>  Be sure to add protection measures according to protection requirements before product testing;

>  Generally, the test rate is 30 ~ 60S once, which should not be too fast, so that the performance of the protection device can be restored.

>  Test times: 5 times for positive/negative polarity.

Test the severity rating