High voltage direct current power supply system earth electrode line earth short circuit fault positioning method

Abstract

The invention discloses a high voltage direct current power supply system earth electrode line earth short circuit fault positioning method, mainly comprising the steps of A, data collection: when judging that an earth electrode line is faulted, acquiring an earth electrode line neutral bus voltage signal and current signals of two earth electrode lines in real time; B, data processing: extractingthe characteristic harmonic components of the earth electrode line neutral bus voltage signal and the two earth electrode line current signals via a full-wave Fourier algorithm; C, computing characteristic harmonic measurement impedances of the two circuits; D, judging the faulted branch having earth electrode line earth short circuit: computing a characteristic harmonic measurement impedance amplitude ratio k, and judging the faulted branch according to k; and E, determining a fault distance with the earth electrode line earth short circuit: performing fault positioning according to a ranging function deduced from a characteristic harmonic measurement impedance expression. The method provided by the invention is strong in transition resistance tolerance capability, high in positioning accuracy, low in implementation cost and easy to implement in engineering.

Description

technical field [0001] The invention relates to the technical field of electric power system fault location, in particular to a method for locating a grounding short-circuit fault of a grounding electrode line of a high-voltage direct current transmission system. Background technique [0002] The grounding electrode is an important part of the HVDC transmission system, which plays the role of providing a path for the unbalanced current and clamping the neutral point voltage. The distance of the ground electrode line is long and the geographical environment is complex, so it is extremely difficult to troubleshoot the line fault. Therefore, after the ground electrode line fails, quickly and accurately determine the fault location, which is conducive to ensuring the safe and stable operation of the large power grid. [0003] The fault location methods of grounding electrode lines can be divided into three categories at present, which are pulse injection method, traveling wave m...

AI Technical Summary

Problems solved by technology

However, in engineering practice, due to the insufficient research on the impedance monitoring mechanism in the high-frequency signal environment, the grounding electrode line impedance monitoring system has the problem that the accuracy of instantaneous fault location of the grounding electrode line is not high.

The traveling wave method is a fault location method based on the propagation law of the fault traveling wave on the line, and calculates the fault distance by detecting the time when the traveling wave head reaches the single end or both ends of the line; The accuracy requirement is very high, but the fault signal of the grounding electrode line is not large, and the attenuation is obvious in the process of catadioptric reflection, which will bring great challenges to the reliability of the distance measurement of the traveling wave method

The fault analysis method is a fault location method based on the fault impedance distribution law. This method uses the electrical quantity collected at the measurement end of the ground electrode line, the line equivalent circuit and line parameters to analyze the fault characteristics, and based on this, a specific distance measurement algorithm is constructed. Then the fault location is obtained. However, the existing algorithm is greatly affected by the transition resistance, and the ranging accuracy is low in the event of a high-resistance fault. Inner iterative search for fault points, a large amount of calculation will undoubtedly lead to cumbersome and complicated solution process

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