Cables have a very important application scenario in our daily lives, you can say that our lives cannot leave the cable. In order to ensure the normal use of the cable, it is necessary to test the cable to be detected and maintained. If the cable fails, you should find a very important application scenario in our daily life, you can say that our lives cannot leave the cable.
In order to ensure the normal use of the cable, it is necessary to test the cable to be detected and maintained. If the cable fails, you should find a fault point in time to overhaul. There are a lot of cable troubleshooting methods. Today, I will introduce one of the high voltage cable fault detection methods, pulse flashing method.
For high resistance failure, since the fault point resistance is large, the reflection coefficient of this point is small or almost equal to zero. When the low pressure pulse method is measured, the reflection pulse of the fault point is small or there is no reflection, and thus the instrument does not distinguish. Commonly used high-pressure flashing measurement methods have two, ie DC high-pressure flashing measurement (referred to as straight flash) and impact high pressure flashing method (referred to as flushing). First, DC high pressure flashing method (referred to as straight flash) When the fault resistance is extremely high, it has not been applied to the measured cable using a step-by-step DC voltage before the stable resistance channel is not formed.
When the voltage value is first selected, the fault point is preferred, and the flash is formed, and the added voltage is formed by a flash reflection, and the reflected echo is reflected by the high resistance source in the input. Such a voltage will be reflected multiple times between the input and fault points until energy is exhausted. Second, Impact High Voltage Flash Method (referred to as Flashing Method) When the fault resistance is lowered, after the stable resistance channel is formed, the DC high pressure cannot be added due to the limited device capacity, and the impact voltage test is required.
DC high pressure The cable is charged with the cable until the breakdown is broken, and the flash reflection is still generated using the flash arc formed. Add the measurement inductance L to read the echo. The radio wave is reflected in a short circuit in the fault point, and is reflected in the input terminal, and a plurality of reflections will be formed therebetween.
Since the self-inductance L of the inductor L, since the blocking effect of L is rendered, the short circuit reflection is present as the current increases for a certain period of time. And the entire line is also made up of capacitance C and inductance L.—Current process of disc. Therefore, the wave process presented in the line input is a rapid pulse multi-reflection wave near the attenuation cosine curve.
Third, high-voltage cable fault detector usage method Generally high voltage cable fault is a high resistance fault, using high pressure flashing method to measure the fault point distance. This method uses ST-330B cable fault rangingmeters as experimental equipment. 1
2, device operation (1) boot, select the sampling method as a flash drive, pulse width default, cable type selection physical type, read accuracy is default. (2) Use the high voltage device to discharge the cable, then click the orange sampling button on the right side, the device starts sample until the waveform is used, and then the sample button is stopped again to stop the sample. (3) Study the waveform, move the roofer to the starting point and termination point of a waveform, read the waveform, and automatically measure the fault point distance.
Regarding the relevant content of the high voltage cable fault detection method, I will introduce it to you today. I hope I can bring a certain help to people need! .
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