Detection method of short-circuit fault point of high-voltage single-core cable

Abstract

The invention relates to a detection method of a short-circuit fault point of a high-voltage single-core cable. The method is used for determining a specific position of a fault point in a cable suffering from a short-circuit fault, and comprises steps of taking n sampling points in the cable; assuming that each sampling point suffers from a short-circuit fault and carrying out simulation; calculating the phase position difference of current of protection layers on two ends of the cable when each sampling point suffers from the short-circuit fault; carrying out fitting according to each phase position difference to obtain a relational expression between the fault point position and the phase position difference of a corresponding point suffering from the short-circuit fault of the cable; and when a short-circuit fault occurs in the cable, according to the relational expression between the fault point position and the phase position difference of the corresponding point suffering from the short-circuit fault, determining the specific position of the fault point suffering from the short-circuit fault. According to the invention, the specific position where the short-circuit fault occurs in a segment of cable can be quickly and precisely determined; precise positioning can be achieved; online monitoring is achieved; and the fault point can be timely found after the fault occurs.

Description

technical field [0001] The invention relates to a method for detecting a short-circuit fault point of a high-voltage single-core cable for determining the specific location of a short-circuit fault in a section of cable in a cable cross-connection section. Background technique [0002] There are two main modes of cable fault location at present: one is the protection distance measurement using the distance protection device, and the other is the fault location mode of the traveling wave method using the electronic sensor. 1) The principle of distance protection based on parameter identification uses the parameters that change in the system after a fault to form the protection criterion. However, the distribution parameters of power cables have obvious characteristics, include multiple complete cross-connection sections, and the environment of line channels is complex, which will significantly affect distance protection. Algorithm performance. Since the measured impedance is...

AI Technical Summary

Problems solved by technology

In practical applications, the distance protection using line impedance still has inaccurate calculation of line impedance and incomplete line length information, so it is impossible to determine the specific location of the short-circuit fault in the cable

2) The traveling wave method performs fault location by detecting the propagation time of the transient traveling wave on the fault line between the busbar and the fault point. Since the propagation speed of the transient traveling wave is close to the speed of light, the fault location mode based on the traveling wave method exists The problem of noise elimination and wave head time extraction. In addition, multiple cross-connection sections and complex line channel environments cause the wave velocity of long cable lines to be inconsistent and wave impedance to be discontinuous. This method is difficult to apply to actual long cable lines. Precise location of fault location

[0003] The invention patent with the application number of 201611128521.0 "Short-circuit fault location method and device for high-voltage single-core cable cross-connection structure" discloses a method for locating short-circuit faults based on the direction of the current signal. Which section of the cable in the cable cross-connection structure the fault occurs in, but the specific fault point in the cable cannot be determined

Images