Author: Noyafa–Cable Tester Suppliers
With the continuous development of power grid construction, ring network cable power supply lines are more and more applied to urban distribution network construction. At present, after a ground fault occurs in the cable, the entire system is grounded, and the fault section is difficult to identify. After distinguishing the cable section, it is necessary to find the cable fault point. Due to the large workload and low safety of the traditional offline fault location method, the power failure test It will also cause certain economic losses. The urban ring network power supply cable line ground fault early warning and positioning technology can quickly and effectively determine the hidden fault, accurately locate the fault point, and has the function of ring network branch line selection.
Therefore, it is of great significance to study the online fault location method of the urban ring network cable to improve the quality of power supply. Using the current traveling wave signal generated by the fault to measure the fault distance is a relatively mature technology, which has been successfully applied in transmission lines and some distribution lines with simple structures. However, urban cable networks are mostly of ring network cabinet structure, with a large number of branch lines, serious initial fault attenuation of traveling waves, and complex refraction and reflection laws. device) and single-ended (only the traveling wave ranging device is installed at the busbar) traveling wave ranging technology cannot be directly applied.
According to the specific structure of the cable network, it is an effective solution to install the current traveling wave acquisition device on the trunk cable and the feeder branch cable of the ring main unit to realize the distributed traveling wave distance measurement and line selection of the fault. The urban ring network power supply cable fault warning and line selection and positioning system uses the system method of high-speed transient traveling wave online monitoring and power grid topology analysis to realize the online monitoring of the ring network cable, and carry out early warning, line selection and positioning for the urban ring network cable fault. The specific method is to install the current traveling wave acquisition device on the main cable and the outgoing cable of the ring main unit respectively, and collect the weak transient signal of the cable before the fault to each system device, analyze and process the system device, and upload the signal to the system device. In the background of the system, the background of the system automatically gives early warning through waveform analysis and automatically calculates the distance of the fault point through the double-end ranging technology, indicates the position of the fault point through the background of the system, and realizes the function of line selection for the feeder branch cable.
Schematic diagram of the installation of the ring network cable monitoring system.
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