Earth fault distance measurement method based on traveling wave modulus time difference

Abstract

The invention relates to an earth fault distance measurement method based on traveling wave modulus time difference, belonging to the field of power electronic technology. The invention utilizes traveling wave detection devices installed at detections points along the line to ensures an effective detection point closer to a fault point to accurately distinguish a zero mode and a line mode initial wave head, and uploads the time difference between the zero mode and the line mode initial wave head into a monitor station. The monitor station is used for sequencing all the collected modulus time difference from big to small, firstly judges the detection point which is closed to the fault point for a first step, and then completing accurate fault distance measurement according to the primary locating result. The invention does not need a time synchronous system, has low communication traffic, is not influenced by line tap points, is easy for project implementation, and has higher reliability and distance measurement accuracy.

Description

technical field [0001] The invention relates to a method in the technical field of power electronics, in particular to a ground fault distance measurement method based on time difference of traveling wave modulus. Background technique [0002] At present, the methods of traveling wave fault location are mainly divided into two categories: A-type single-ended ranging method and D-type double-ended ranging method. Linear-mode wave head arrival time is achieved. Although the single-ended method does not require a GPS synchronous clock, the equipment cost is low, and it is basically not affected by the error of the line length, but due to the defects of the principle itself, it is difficult to correctly distinguish the reflected wave of the fault point from the reflected wave of the opposite bus, and the ranging accuracy cannot be achieved. ensure. Although the distance measurement reliability of the double-ended method is higher than that of the single-ended method, the dista...

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Problems solved by technology

[0004] After searching the existing literature, it was found that "Power System Automation" published an article entitled "A new method for small current ground fault location based on transient zero-mode current approximate entropy" in the 20th issue of "Power System Automation" in 2009 (p83-p87). This paper proposes a fault location method by judging the approximate entropy of transient zero-mode current at adjacent detection points, but this method can only determine the fault section (the section between two adjacent detection points including the fault point), and Accurate fault location cannot be achieved

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