A power cable fault location method and system

Abstract

The invention discloses a power cable fault location method and system. The method includes: obtaining the head end current, end current, head end voltage and end voltage of the faulted power cable; according to the head end current, end current and head end voltage of the power cable Calculate the line wave impedance of the power cable with the end voltage; calculate the line propagation coefficient of the power cable according to the head current, end current, head voltage, end voltage and line wave impedance of the power cable; calculate the fault point according to the line wave impedance and line propagation coefficient The distance to the start of the power cable. The power cable fault location method and system proposed by the invention can more accurately calculate the distance from the fault point to the head end of the power cable, and improve the fault point location accuracy.

Description

technical field [0001] The invention relates to the technical field of fault detection, in particular to a power cable fault location method and system. Background technique [0002] Cross-linked polyethylene (XLPE) power cables have been widely used in transmission and distribution networks of various voltage levels in power systems due to their good insulation properties, mechanical properties, thermal properties and high power supply reliability. , has become an important part of the city's power supply and main grid, and is constantly developing into the field of high voltage and ultra-high voltage. In the early stage of operation of XPLE cable lines (generally 1-5 years), the quality of cables and accessories or laying and installation is prone to failure; in the middle period of operation (5-25 years), the probability of failure of cable lines is low, but the cable There are many types of faults, such as line faults caused by damage to cable insulation due to external...

AI Technical Summary

Problems solved by technology

The single-ended ranging method is greatly affected by the system impedance and transition resistance of the opposite end of the line; the double-ended ranging method has more advantages, which eliminates the influence of transition resistance, and can achieve accurate fault detection under the premise of ensuring accurate sampling data and line parameters. positioning, but the double-terminal ranging method not only needs the double-terminal voltage and current values ​​to calculate the fault distance, but also needs to know the primary parameter value of the cable, and calculate the wave impedance and propagation coefficient according to the primary parameter value, so as to calculate the fault distance, but When the cable fails, the primary parameters of the cable cannot be calculated by the formula at this time, and the accurate values ​​of wave impedance and propagation coefficient cannot be obtained, resulting in a large error in the calculation of the fault distance, and the exact fault location cannot be determined

Most of the ranging algorithms that have been proposed use the method of search and iteration to locate faults. The ranging accuracy is affected by factors such as the number of iterations and the iterative step size. To obtain higher accuracy, a large number of calculations must be performed, which takes too long and cannot be fast. Locating the location of the fault point

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