NOYAFA Electronic specializing in testing instruments and cable testers for 16 years
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NOYAFA Electronic specializing in testing instruments and cable testers for 16 years
Author: Noyafa–POE Tester
What are the commonly used test methods for cable fault location? What are the commonly used test methods for cable fault location? The impulse circuit and the arc ignition circuit are divided into two parts. The impact circuit mainly prevents the impact breakdown of the fault point, and the impact energy obtained at the fault point is relatively large. When the impulse voltage drops and stabilizes, the arc-striking capacitor applies a small current through the arc-striking circuit, prolongs the flashover and breakdown time of the fault point, loads the low-voltage pulse test signal, and tests the fault point interval (short-circuit waveform).
Due to the special arc ignition circuit, the arc ignition time can reach several tens of milliseconds, so it is easier to obtain an effective waveform. Product name: Integrated high voltage signal generator with battery. The difference between the double-pulse method and the triple-pulse method lies in the way the signal is collected and processed.
The third pulse method was first proposed by Germany. Due to the large size and heavy weight of the whole machine, it is only used for the cable test vehicle of the German company. Under the action of impulse voltage, when the fault point is short-circuited by arc breakdown, one (or more) low-voltage test pulses are issued, and the short-circuit reflected echo can be obtained at the short-circuit point, that is, the polarity of the reflected echo is the same as the polarity of the transmitted pulse. Sex is the opposite.
When the short-circuit arc at the fault point is extinguished, a low-voltage test pulse is sent to measure the full-length waveform of the cable. The waveforms before and after the two acquisitions appear on the screen at the same time, and are automatically closed, aligned and superimposed. The open circuit full-length waveform has the same polarity as the launch pulse, and the defect reflection waveform has the opposite polarity to the launch pulse and must be within the full-length interval.
The two test waveforms before the fault point conform to a good law. Once the fault point crosses, the two waveforms will be discrete and no longer overlap. The discrete points of the two curves are the distances from the fault point to the test terminal.
The secondary pulse method has been widely used in my country due to its simple circuit and good waveform after the fault is clicked. However, since the pulse capacitor is also used as the ignition capacitor, the ignition time is greatly shortened, and it is sometimes difficult to obtain an effective waveform. The repetitive pulse method is a great improvement in this regard.
What are the commonly used test methods for cable fault location? Shenzhen Noyafa Electronic Technology Co., Ltd.
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