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 Tester Manufacturer
Question: What are the methods for accurate spotting of the cable fault tester? Answer: The cable fault tester has several methods to determine the cable fault: (1) Sound measurement method: The use of sound measurement legal points is from the past to the present. Cable fault location problem: What are the methods for accurate positioning of the cable fault tester? Answer: There are several methods for the cable fault tester to determine the cable fault: (1) Sound measurement method: The use of sound measurement legal points is a common method for cable fault location from the past to the present. This is the valid method. However, the instrumentation used has evolved from the simple acoustic amplifiers of the past to the now commonly used acousto-magnetic synchronized fixed-point instruments.
The sound measurement legal points apply to high voltage cables, low voltage cables, direct buried cables, cable trench cables, etc. (2) Step-by-step voltage method: The step-by-step voltage method is adopted, which is mainly used to locate the ground fault of the outer sheath required for the insulation of the outer sheath of the cable. Step voltages are now also available for some directly buried unarmed low voltage cables and core ground faults.
legal point of view. (3) Electromagnetic method and audio method: In principle, it is feasible for the cable fault tester to use electromagnetic waves to fix the point or adopt the audio legal point, that is, to determine the fault point by using the changes of the electromagnetic wave signal or audio signal before and after the cable fault point . However, from the current situation, there is no reliable nursing instrument that can be used in practice.
In other words, fixed-point instruments using electromagnetic waves are still in the research and development of various scientific research institutions, and further verification and improvement are needed before they can reach the practical application level. (4) Acoustic and magnetic synchronization method: The cable fault tester is a comprehensive application of the sound measurement method and the electromagnetic wave method. For example, the DTC series acousto-magnetic synchronous pointing instrument adopts the fixed-point principle of the sound measurement method and the acousto-magnetic synchronous fixed-point method.
When measuring the sound point, the sound meter of the pointing instrument indicates the seismic wave received by the sound measuring probe, and the earphone also reflects the sound wave received by the sound measuring probe. Just above the fault point, the acoustic signal is maximum, away from the fault point, the acoustic signal decreases, or there is no acoustic signal. (5), Magnetic field progress technology: The principle of the cable fault tester is: through the high-voltage DC pulse generator, the arc at the fault point of the cable is generated, and the audio signal is injected into the cable during the existence of the arc.
The audio signal is shorted by the arc at the point of the cable fault and no longer propagates to the cable termination. A dedicated receiver is used to receive the audio electromagnetic wave signal radiated by the cable. By comparing the amplitudes of the audio frequency electromagnetic wave amplitudes before and after the fault point, it is judged that the receiver is located before or after the fault point, so as to achieve the purpose of quickly pre-determining the point.
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