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–Cable Length Tester
With the wide application of Internet technology, the intelligent cable fault detection flash tester is gradually put into use, and the detection principle used is still the single-pulse reflection method. The flash tester used is from the picture tube display to the LCD display, and the single-chip design is widely used to make adjustments, so that with the wide application of Internet technology, the smart cable fault detection flash tester is gradually put into use, and the detection principle used is still single pulse. reflection method. The flash tester used is from the picture tube display to the LCD display, and the single chip design is widely used to make adjustments, so that the rough test operation of the cable fault detection has entered a new pattern.
Next, the editor will share some knowledge about the fault detection of the cable routing instrument. There are two methods for rough measurement of cable faults: bridge method and pulse reflection method. There are the following methods for cable fault determination: 1. Acoustic measurement method: The use of acoustic measurement method is the method that has been widely used from the past to the present. And it is the most effective method.
It's just that the instrument used has developed from the simple acousto-electric amplifier in the past to the commonly used acousto-magnetic synchronous pointing instrument. Acoustic measurement method is applicable to high-voltage cables, low-voltage cables, directly buried cables, cable trench cables, etc. 2. Step voltage method: The step voltage method is adopted, which is mainly for the ground fault of the outer sheath that requires the insulation of the outer sheath of the cable. Step voltage quorum points may be used.
3. Electromagnetic method and audio method: It is feasible in principle to use electromagnetic wave to fix the point or adopt the audio frequency method. But from the current situation, there is no fixed-point instrument with reliable performance that can be practically applied. In other words, the fixed-point instrument using electromagnetic waves is still being developed by various scientific research institutions, and it needs to be further verified and improved in practice to reach the level of practical application.
Using electromagnetic waves for path detection is a very mature method, and the practical application effect is also very good. The difference lies in the length of the cable detected, the depth of detection, and the frequency of the signal. The current popular path meter, the length of the detection cable is more than 10KM, the depth of the detection cable is more than 2m, and the frequency of electromagnetic waves is 10KHZ-20KHZ.
Most of the medium and low voltage cable routing instruments on the market now complete the function of rough detection of cable faults. The principle is generally to use the bridge method, but now the computer technology has been used, using a smart bridge. There are low-voltage bridges, high-voltage bridges, and so on.
Some instruments also use the principle of ultra-high voltage digital bridge. The voltage applied to the fault point is generally above 200V, and the maximum can be added to 20KV. For low fault resistance (resistance less than 600MΩ) cable failure.
The fault distance can be roughly measured with the medium and low voltage cable detector. For cable faults adapted to the test, its use is simple, and the technical requirements for users are not high. which is“fool”type test.
In addition, for some fault points, such as some cable joint faults, due to the long creepage distance of the fault point, it cannot be formed.“Flashover”For the discharge fault, since it is impossible to use the pulse method to measure the fault distance roughly, the bridge method has its advantages.
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