High-voltage direct-current transmission line single-end protection method based on specific frequency voltage

High-voltage direct-current transmission line single-end protection method based on specific frequency voltage

  • CN 107,919,656 B
  • Filed: 12/09/2017
  • Issued: 11/06/2020
  • Est. Priority Date: 12/09/2017
  • Status: Active Grant
First Claim
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1. A single-end quantity protection method of a high-voltage direct-current transmission line based on specific frequency voltage utilizes the magnitude of the variable quantity of the single-end specific frequency voltage of the high-voltage direct-current transmission line to realize the discrimination of faults inside and outside a region, and comprises the following steps:

  • (1) the method comprises the steps that voltage signals of a rectifying side of the high-voltage direct-current transmission system are collected in real time through protection of the rectifying side, voltage with specific frequency is extracted through a Discrete Fourier Transform (DFT) algorithm of a sliding window, and the specific frequency is the parallel resonance frequency of direct-current filters at two ends of a direct-current circuit;

    (2) calculating the average voltage value within 3ms according to the specific frequency voltage extracted by the rectification side protection according to the following formulaJudging whether the protection threshold value meets the protection starting criterion or not, and starting protection if the protection threshold value is greater than the protection starting threshold value;

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