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
Since the 1960s, my country's power cable has been widely used, with limited grade, narrow application range. At that time, in order to solve the cable failure, the researchers developed a low-voltage cable fault detector based on the flashing method. Since the 1960s, my country's electric cable has been widely used, and its grade is limited, and the application range is narrow.
At that time, in order to solve the cable failure, the researchers developed a low-voltage cable fault detector based on the flashing method. The instrument test cable failure has three steps. Let's introduce it to you.
First measure the distance by the rangefinder. In fact, first, it is necessary to determine whether the cable fault is a high impedance or a low-resistance or ground, and uses different test methods according to this situation. If it is a ground fault, the distance is measured directly with the low pressure pulse detector of the low voltage cable; if it is a high-resistance failure, it is necessary to measure the distance with high pressure impact discharge.
Many auxiliary equipment such as high pressure pulse capacitors, discharge balls, current limiting resistors, inductive coils, signal samplers, and the like are required. It is not safe to operate, there is a risk. What is more trouble is to analyze sampling waveforms, which is higher for testers.
The second step is to find the path (if the path is clear, this step can be omitted). When looking for a path, add a signal (path signal generator) to the cable, and then receive the signal with the receiver and determine the cable path again along the signal path. However, this path has a range between 1-2 meters and is not particularly accurate.
The third step is to accurately position according to the measured distance. Its basis is the sound generated by the flame discharge, and when he heard the sound of the sound from the headset of the fixed point, it is to find the position of the fault point. But because it is listening to sound, therefore, it is a considerable fee, sometimes it is necessary to wait until you can find it.
It takes more time to encounter cross-linking cables because the cross-linking cable is generally discharged internal, and the sound is small, and it is almost not able to measure. The cables used in other industries are also characterized, and it is not described in detail here. However, with the continuous development of science and technology, we should be able to find a simpler test method, classify cable faults, the disease, specific problems, so that we will find that some cables do not need the principle of flashing It is very convenient to solve it.
In addition, the low-voltage cable has the following features in actual use: 1. The randomness of laying is relatively large, and the path is not very clear. 2. When it is laid, it is not as deep as a high-voltage cable, which is deeply buried, and the opposite buried is shallow, and it is easily damaged by external force. 3, the cable is generally shorter, from dozens of meters to several hundred meters, unlike high voltage cables, often between several hundred meters to a few kilometers.
3, the insulation strength requires low, and the process is simple when handling the fault. Most cables have very obvious flake damage in the fault point. There is no trace in the outer skin of the cable, it is very rare.
6, the load changes, often unbalanced, easy to heat, resulting in more than common faults. Ok, about the basic method of low-voltage cable fault detection, I will introduce it to you, I hope I can help everyone.
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