The occurrence of ACSR Cable 336.4 MCM faults is accompanied by the laying and use of cables. The location of cable faults varies with cable laying methods, and the difficulty in locating is gradually increasing. Among them, the positioning and searching of bridges, tunnels, and trenches are relatively simple, while the direct-buried method is the most difficult to locate. When the nature of the fault is simple, a dedicated cable fault location device can be used to locate the fault within tens of minutes. When the fault is special, it often takes 4-5 days or even longer to locate the fault.
When using the echo method to locate cable faults, sometimes through the transfer of faulty phases and wiring methods, complex faults are often transformed into simple faults, and the fault location can be quickly determined to gain time for on-site line repairs. This is important for power supply departments. Significant.
Low-voltage power cables are generally multi-core cables. After a fault occurs in continuous use after laying, they generally show two-core and multi-core phase-to-phase or relative-to-ground short-circuit faults. Sometimes when it is detected that the fault waveform collected by a certain core is not ideal, consider switching the wiring to other faulty cores for fault waveform detection. Unexpected effects will often occur, and the collected and detected waveforms will become More typical and regular, so you can quickly determine the specific location of the cable fault point.
In the long-term on-site measurement process of cable customers, it is found that after the failure of small cross-section copper core direct-buried power cables (35mm2 and below) and aluminum core cables, there may be short-circuit and disconnection faults at the same time. During on-site detection, according to the nature of the failure of each faulty core The difference between the short-circuit fault and the disconnection fault measurement will often get twice the result with half the effort.
For low-voltage cable and direct-buried power cables with extruded armored inner lining, most of the faults are caused by external mechanical damage. When the insulated core fails, the inner lining may have been damaged. When encountering a special cable insulation fault, it is difficult to use a professional cable fault meter to collect waveforms. Consider using the acoustic measurement method to directly apply high-voltage pulses between the steel strip and the copper shielding layer of the cable, which will often quickly fix the point.
During the on-site measurement process, we also found that when the low-voltage cable fault point is determined by the acoustic measurement method, when the high-voltage wire and the ground wire are connected between the bad phase and the metal shield or armor, the insulation resistance of the two shows a low-resistance metallic connection. State, the sound is very small, the probe cannot be used to listen to the fixed point, and the effect is not ideal. Through the actual listening side many times, it was found that the distance between the discharge ball gaps was appropriately increased, and the high voltage and grounding wires were reconnected between the two phases where the fault occurred. Often the discharge sound will become louder, and the fault point will be quickly determined. .