The power cable is a safe key to the carrier of rail transportation and power supply, whether it is a medium pressure ring cable or a direct fluid feed line. However, the lack of environmental differences (cable ditch, bridge), and the previous construction process affects cable extremely easier damage or insulation. Moreover, the power cable is a safe key to the carrier of rail transportation and power supply, whether it is a medium pressure ring cable or a direct current feed line.
However, the lack of environmental differences (cable ditch, bridge), and the previous construction process affects cable extremely easier damage or insulation. And when the fault occurs, the fault point positioning is difficult, maintenance is difficult, the maintenance cycle is long, the loss is much larger than the overhead line. Therefore, we are mainly for power cable faults to find a discussion.
Cable fault point lookup is one of the common, difficult to exclude failures in electricity, how to use the instrument, method, to find the fault location, thus rapid, effectively eliminating the fault, worthy of serious research and master. The following from the power cable fault cause, the fault classification, finding steps, the common range of ranging positioning methods, I hope everyone is familiar with the master. First, there are many reasons for the failure of the power cable, and it is summarized: 1. The cable is damaged by external force.
From the point of view of cable failure, the proportion of cable faults caused by external force factors such as mechanical construction, excavation, piling, transportation, and installation damage increases year by year. 2, product quality problems. After the cable is running, if the cable and cable attachment manufacturing process, the insulating shield is uneven, the insulation is eccentric, the internal and external shield is protruding, the insulating impurities, the conductor or semiconductive production is uneven, the cable metal outer sheath is poor, protrude, Bubbles or spikes, etc., will cause chronic failures after the cable run.
3, lay the quality of the equipment. When the wire is applied, the construction machine, geographical conditions (including environmental conditions and climatic conditions) and the construction machine and the quality conditions of the personnel conditions may occur, and the two ends of the cable, the cable outer sheath, the cable outer sheath, the cable bending radius, Cable metal shielding layer break, cable body mechanical stress internal injury and other construction mistakes, initiating cable early operation failure. Second, the step of the power cable fault lookup.
Detection steps of cable failure, according to professional experience, as follows: 1. Judging the nature of cable fault: According to the electricity signal and protection operation in the cable failure, the cable appearance is initially judged. In the preliminary judgment, a rocking table can be used, and the faulty cable of the fault cable can be used to determine the faulty cable faulty cable, and the determination is determined according to the preliminary judgment, the selection of the fixed point method is performed. 2, determine the cable fault position: Rang.
According to the preliminary judgment of the fault, rough testing of the fault point and determine the range of cable fault points. Use the appropriate preset method to provide detailed information for accurate positioning, and reduce the precise positioning range. Depending on the different fault nature, the cable fault pre-positioning method can be divided into line and impedance.
3. Accurate positioning of cable failure: positioning. Prerequisites are known cable laying paths. If you don't know, you should follow it first. Based on the range of fault positioning, through the search of the cable laying path, gradually narrow the suspicious fault point, and then determine the exact position of the fault point with the acoustic detector within this range.
Common measurement methods have sound magnetic synchronization accepting fixed-point method, audio induction method, stepwork method. The above is the relevant content of the power cable fault search, I hope that people need to help with people need.
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