Author: Noyafa–Noyafa Cable Tester
Where to use the smart cable fault tester Where to use the smart cable fault tester How does the cable fault tester work? The working principle of the cable fault tester is to measure low first without damaging the fault point of the cable under test. Where is the smart cable fault tester used and where is the smart cable fault tester used? What is the operation method of the cable fault tester? The working principle of the cable fault tester is to first measure the reflected waveform of the low-voltage pulse without destroying the fault point of the cable under test, and then use the high-voltage pulse to impact the fault point of the cable to generate an arc. When the arc voltage drops to a certain value, the medium voltage is triggered. The pulse stabilizes and prolongs the arc time, and then sends out a low-voltage pulse, so that the reflection of the fault point can be obtained after the two waveforms are superimposed, and it can also be found that the divergence point is the corresponding position of the fault point. Because the medium voltage pulse is used to stabilize and prolong the arc time, it is easier to obtain the fault point waveform than the secondary pulse method. Compared with the second pulse method, the third pulse method does not need to select the synchronization time of the arc, and the operation is convenient.
The double-impulse method is used to prolong the arc starting time and to stabilize the arc. The three-impulse method can easily locate high resistance faults and flashover faults. The third pulse method has advanced technology, simple operation, clear waveform and fast and accurate positioning. It has become the mainstream method for locating high resistance faults and flashover faults.
The third pulse method is an improvement of the second pulse method. The total length and approximate location of the cable fault from the test end to the point of failure. The cable fault point tester determines the exact position of the cable fault point on the basis of the cable fault tester host determining the approximate position of the cable fault point.
For buried cables with unknown trends, the working principle of the power cable fault tester is mainly composed of three parts: the power cable fault tester host, the cable fault locator and the cable path tester. The main unit of the cable fault tester is used to measure the nature of the cable fault. A pathfinder is needed to determine the underground route of the cable.
The basic method of power cable fault test is to apply a high voltage pulse to the faulty power cable. The fault occurs at the fault point of the cable, and the fault point of the cable discharges at the same time, generating external electromagnetic waves and sound at the same time. Run the high resistance fault point of the cable through the arc. At the same time, a low-voltage pulse for measurement is added to the test end.
When the measurement pulse reaches the high-resistance fault point of the cable, the surface of the arc will reflect as it encounters the arc. Since the high-resistance fault becomes an instantaneous short-circuit fault during arcing, the low-voltage measurement pulse will have obvious impedance characteristic changes, making the flashover measurement waveform a low-voltage pulse short-circuit waveform, making the waveform identification very simple and clear. This is called the second pulse method, and it receives the reflected waveform of the low voltage pulse, which is equivalent to a complete short circuit between the core and ground.
The low-voltage pulse waveforms obtained when the high-voltage pulse is released and when the high-voltage pulse is not released are superimposed, and the two waveforms will have a divergence point, which is the reflected waveform point of the fault point. This method combines the low-voltage pulse method with the high-voltage flashover technology. Combined, it makes it easier for the tester to locate the point of failure. Compared with the traditional test method, the working principle of the arc reflection method (second pulse method) in cable fault location is as follows: first, a high-voltage pulse with a certain voltage level and a certain energy is applied to the cable test end. In the advanced part of the secondary pulse method, the complex waveform in the high-voltage flashover method is simplified to the simplest low-voltage pulse short-circuit fault waveform, the explanation is very simple, and the fault distance can be accurately calibrated.
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