Fast Tracking Judgment Method for AC Impedance of Transmission and Distribution Line Faults

Abstract

A method for quickly tracking and judging fault AC impedance of transmission and distribution lines, which is composed of a high-voltage AC detection power supply (1), a current detection unit (2), a voltage detection unit (3) and a line sensor (4). When the transmission and distribution line is faulty and tripped, after a certain time interval T, the line sensor installed outside the line switch sequentially applies high-voltage AC detection signals to the phase-to-ground and phase-to-phase of the line, and calculates the phase-to-phase impedance Za0 and Zb0 of the faulty line And Zc0 and interphase impedance ZAb, Zbc and ZAc. And compare the detection results with the minimum operating criteria Za0j, Zb0j and Zc0j and ZAbj, Zbcj and ZAcj of the line to track and judge whether the line fault is a transient fault or a permanent fault and the recovery of the fault. Because the detection method is fast and accurate in judgment, it is suitable for line grounding short circuit and interphase short circuit, so the invention has better practicability.

Description

technical field [0001] The present invention mainly relates to the field of fault diagnosis of transmission and distribution lines, in particular to a method for quickly tracking and detecting faulty lines after a fault trips on a transmission and distribution line, which is applicable to the rapid detection and judgment of the nature of a fault after a fault trips on a transmission and distribution line and the fault Status fast track. Background technique [0002] The faults of power lines are divided into two types: transient faults and permanent faults. After the transient faults are removed by relay protection, the arc at the fault point will be extinguished immediately and the insulation strength will be restored. At this time, if the disconnected line is reclosed Reclosing restores normal power supply. However, permanent faults may also occur on the line. Permanent faults refer to permanent insulation breakdown short circuits between phases or phases, such as faults ...

AI Technical Summary

Problems solved by technology

However, if the DC high voltage is used to track the insulation resistance of the faulty line, the charging time of the long line or the cable line will be long, and the faulty line cannot be diagnosed quickly.

If it is a phase-to-phase fault of the line, it cannot be realized by using the method of detecting insulation resistance with DC high voltage due to the existence of phase-to-phase components (such as phase-to-phase windings of transformers) in the line.

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