As an important medium for power transmission, high-voltage cables have many advantages such as outstanding electrical functions, heat resistance, and strong mechanical functions. Cable joints have been widely used in the transmission and distribution of power systems in recent years; however, it is difficult to avoid the existence of high-voltage cables. Defects, especially in the production process of high-voltage cables, it is difficult to ensure that the insulation is intact. When installing and laying cables, the insulation is damaged by mechanical force, and more importantly, due to moisture and soil erosion after long-term use If the insulation is damaged by corrosion, these dangers will eventually cause the breakdown of the high-voltage cable insulation. High-voltage cables are quite difficult to troubleshoot and repair due to their special laying.

Cable partial discharge positioning method

When detecting the cable discharge, if the position of the part of the discharge source can be found, the efficiency and accuracy of the discharge detection will be greatly improved. In order to achieve this intention, the time domain reflection method is usually used to determine the discharge position, that is, Tim Domain Reflectometry.TDR. The application mechanism of this method is as follows: set up the pulse detection equipment at one end of the cable, and use the reflection principle caused by the partial discharge pulse to be transmitted in the cable, so as to obtain the same pulse back and forth in the cable and the time difference data, and then use to find the pulse The position is used to determine the position of the partial discharge source. If the partial discharge signal coupling device is installed at the near end of the cable, the pulse current method can be used to detect the impedance. Of course, it is also possible to find the position of the discharge pulse signal through a high-frequency current sensor and other methods. Once the cable connector is partially discharged, the generated pulses will form two signals with the same amplitude, and they will be transmitted in the cable line in opposite directions. Different signals will have different transmission times, and the arrival delay of the two signals will be used. The difference, referring to the transmission speed of the pulse in the cable and other parameters, can roughly determine the area where the partial discharge pulse is announced. Similarly, when the power cable is charged, the sensor can also detect a similar pulse group signal, and the direction can be used to initially determine the position of the partial discharge source. As long as the position of the partial discharge source is found, the fault location can be found, and further Take measures to remove faults to ensure the normal operation of the cable.