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Extra-high voltage direct current transmission line boundary element forming method based on support vector machine

A UHV DC and support vector machine technology, applied in the direction of DC network circuit devices, electrical components, knowledge-based computer systems, etc., can solve the problem that the threshold value is not easy to determine

Active Publication Date: 2011-04-06
KUNMING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although traveling wave protection has many advantages, according to the relevant data of actual operation at home and abroad, traveling wave line protection based solely on the rate of change can operate accurately under various fault conditions, and its threshold value is not easy to determine

Method used

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  • Extra-high voltage direct current transmission line boundary element forming method based on support vector machine
  • Extra-high voltage direct current transmission line boundary element forming method based on support vector machine
  • Extra-high voltage direct current transmission line boundary element forming method based on support vector machine

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Embodiment Construction

[0079] Simulation model such as figure 1 As shown, a positive ground fault occurs at a distance of 100km from the protection installation, the fault transition resistance is 0.1Ω, the time window length is 2ms, and the sampling frequency is 100kHz.

[0080] (1) After the DC line fails, the starting element starts immediately, according to the formula:

[0081] P 1 (k)=Z p × i 1 (k)-u 1 (k) (10)

[0082] P 2 (k)=Z p × i 2 (k)-u 2 (k) (11)

[0083] Calculate the polar wave voltage, the polar wave waveform is shown in Figure (6); where, u 1 (k) is the positive DC voltage, i 1 (k) is positive direct current, u 2 (k) is the negative DC voltage, i 2 (k) is the negative DC current, k=1, 2, 3...N, N is the length of the sampling sequence, Z p is the polar wave impedance of the DC transmission line;

[0084] (2) According to the formula

[0085] S [ m , n ] = Σ k ...

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Abstract

The invention provides an extra-high voltage direct current transmission line boundary element forming method based on a support vector machine (SVM). The method comprises the following steps: when the direct current line has fault, computing the anode line polar wave voltage and the cathode line polar wave voltage according to the direct current voltage and direct current of the two poles measured in the relay location of the line; selecting the discrete polar wave voltage signal of the fault pole, with sampling sequence length of 200, after fault to undergo S transform to obtain a 101*200 time-frequency complex matrix and computing the modules of elements in the complex matrix; computing the energy values corresponding to the first 20 frequencies according to the modular matrix obtainedthrough S transform, sticking tag values to the energy values as the characteristic quantity and inputting the characteristic quantity to the SVM to be trained; and distinguishing the area fault fromthe out-area fault according to the training result of the SVM. Lots of simulation results show the method has good effect.

Description

technical field [0001] The invention belongs to the technical field of electric power system relay protection, and specifically relates to a method for constituting a boundary element of an UHV direct current transmission line based on a support vector machine. Background technique [0002] Traveling wave protection has become the main protection of the existing ultra-high voltage DC line due to its ultra-high-speed operation characteristics and a series of advantages that are not affected by current transformer saturation, system oscillation and long-line distributed capacitance. The existing DC line protection is mainly provided by ABB and SIEMENS. The single-end protection criterion is based on the relative time change rate and current change gradient of the DC line voltage and current. Although traveling wave protection has many advantages, according to the relevant data of actual operation at home and abroad, the traveling wave line protection based solely on the rate o...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02J1/00G06N5/00
Inventor 束洪春方毅田鑫萃刘可真张广斌孙士云贺婷安娜
Owner KUNMING UNIV OF SCI & TECH
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