The impulse withstand voltage test can be used to detect the insulation performance of the electrical equipment when subjected to atmospheric overvoltage (lighting stroke), and then it is used to study the insulation performance of the power equipment subjected to overvoltage.
The impulse voltage test results can be divided into two categories according to the different insulation properties of the test specimens. One is the withstand voltage test. The test object is non self restoring insulation , self recovery insulation and non self restoring insulation test. The other is destructive discharge test, the test object is a self - restoring insulation test.
Impulse voltage generator is a kind of high voltage generator which can generate pulse wave. In the simulation equipment in the lightning overvoltage and operation test voltage tolerance characteristics of short-time high voltage under impact, impulse voltage can produce standard full wave (lightning), chopper, operation, steep wave wave, meet the requirements of all kinds of electrical equipment for impulse voltage test.
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| 500kV 25KJ Impulse Voltage Generator |
Full wave: The full wave is a certain polarity of non periodic pulse voltage wave, the wave of the front part of the voltage rise quickly. If it reached peak and then slowly dropped to zero.
Chopped wave: lightning impulse voltage in the whole wave after a period of time (a few microseconds), cut off by the outer space of the waveform known as the cut-off wave, according to the length of the truncation delay, the cut is divided into wave front truncation and tail truncation.
Operating wave: wave head time Tcr and the definition of the wave tail time T2 the same as the lightning wave, usually in line with Tcr=250 s and T2=2500 s shock wave as a standard operating wave.
Steep wave: voltage conversion, from high to low, and the basic performance of the waveform is not changed as the steep wave.
The reasons for the formation of the four kinds of waveforms are different, when the electric equipment is subjected to the impulse withstand voltage test, according to the different samples, the impulse voltage generator should correspond to different waveforms in the test.
Electrical equipment
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operation waveform
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remarks
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Transformer
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Full wave, chopping wave, operation wave
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Switchgear
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Full wave, chopping wave
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110kV switchgear, GIS
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Transformer
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Full wave
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Lighting Arrester
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Full wave
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Impulse current
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Insulator
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Full wave, steep wave
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If it is a ceramic or glass insulator, must be equipped with steep wave device; if it is consistent with the insulator, can also be synthesized by computer
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