The first is the low-voltage pulse reflection method. This method is mainly used for the detection of cable faults caused by low resistance. When the impedance is low, the impedance of other points does not match the impedance of the fault point. Therefore, in the cable, the low voltage pulse meets the fault point. The reflected pulse will appear, and then the fault point is located based on the calculation of the specific propagation speed of the reflected pulse and the transmitted pulse and the actual difference in round-trip time. The second is the impact high-voltage flashover method. The impact high-voltage flashover method is widely used in cable fault detection. The principle is to apply an impact high voltage to the beginning of a faulty cable and record the sudden voltage spike at the time of breakdown. Data information. Then through research and analysis of the obtained data, accurately locate the fault point, and propose countermeasures. Another is the bridge method. The advantages of the bridge method are high accuracy and easy operation. However, the bridge method is not suitable for detecting high-resistance flashover faults because the bridge current will be high when the fault resistance is high. It is relatively small, which makes testing difficult. In addition, when the bridge method is applied, the length of the cable needs to be known before the test, and when the cross section of each cable and the cross section of the cable line are different, it needs to be calculated before the test. Finally, the cable fault detection method is the second pulse method.