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A longitudinal protection method for UHV DC lines using principal component analysis of pole line fault current curve clusters

An ultra-high voltage DC, fault current technology, applied in fault locations, emergency protection circuit devices, electrical components, etc., can solve the problems of protection failure, amplitude reduction, and inconspicuous transient traveling wave characteristics, so as to improve reliability. Effect

Active Publication Date: 2018-06-15
KUNMING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In UHV DC transmission lines, for high-resistance faults, its amplitude will be greatly reduced due to the existence of transition resistance, and the characteristics of transient traveling waves will not be obvious, so the reliability and sensitivity of protection will be greatly reduced
Once the protection using the amplitude change and its rate of change as the identification criterion fails to capture the initial traveling wave, the traveling wave protection criterion will fail and the protection will fail

Method used

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  • A longitudinal protection method for UHV DC lines using principal component analysis of pole line fault current curve clusters
  • A longitudinal protection method for UHV DC lines using principal component analysis of pole line fault current curve clusters
  • A longitudinal protection method for UHV DC lines using principal component analysis of pole line fault current curve clusters

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] Embodiment 1: The simulation system diagram and fault component network diagram of ±800kV direct current transmission line are respectively as follows figure 1 shown. The line parameters are as follows: the total length of the line is 1500km, the total length of the ground electrode line on the rectification side is 109km, and the total length of the ground electrode line on the inverter side is 80km. Fault location: the positive line is faulty, and the fault occurs 120km away from the rectifier side. The ground impedance is 50Ω, and the sampling rate is 10kHz.

[0031] (1) According to step 1 to step 3 in the instruction manual, construct the cluster analysis space of the principal components of the pole line fault current;

[0032] (2) Put the fault sample into the principal component clustering space according to step 4 in the manual, and obtain its 1 Coordinates and PC 2 The projected value on the coordinate axis (q' 1 ,q' 2 );

[0033] (3) Calculate the proj...

Embodiment 2

[0035] Embodiment 2: The simulation system diagram and fault component network diagram of ±800kV direct current transmission line are respectively as follows figure 1 shown. The line parameters are as follows: the total length of the line is 1500km, the total length of the ground electrode line on the rectification side is 109km, and the total length of the ground electrode line on the inverter side is 80km. Fault location: the positive line is faulty, and the fault occurs at a distance of 950km from the outlet of the rectification side. The ground impedance is 10Ω, and the sampling rate is 10kHz.

[0036] (1) According to step 1 to step 3 in the instruction manual, construct the cluster analysis space of the principal components of the pole line fault current;

[0037] (2) Put the fault sample into the principal component clustering space according to step 4 in the manual, and obtain its 1 Coordinates and PC 2 The projected value on the coordinate axis (q' 1 ,q' 2 );

...

Embodiment 3

[0040] Embodiment 3: The simulation system diagram and fault component network diagram of ±800kV direct current transmission line are respectively as follows figure 1 shown. The line parameters are as follows: the total length of the line is 1500km, the total length of the ground electrode line on the rectification side is 109km, and the total length of the ground electrode line on the inverter side is 80km. Fault location: positive line fault, phase A ground fault on the AC system side from the inverter side. The ground impedance is 10Ω, and the sampling rate is 10kHz.

[0041] (1) According to step 1 to step 3 in the instruction manual, construct the cluster analysis space of the principal components of the pole line fault current;

[0042] (2) Put the fault sample into the principal component clustering space according to step 4 in the manual, and obtain its 1 Coordinates and PC 2 The projected value on the coordinate axis (q' 1 ,q' 2 );

[0043] (3) Calculate the pr...

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Abstract

The invention provides a method for longitudinal protection of UHV direct current lines using principal component analysis of pole line fault current curve clusters, and belongs to the technical field of electric power system relay protection. From the electromagnetic transient simulation, the current curve clusters of the measured terminal lines under the faults within the entire length of the line, forward external faults and reverse faults are respectively obtained, and 2 sampling points before the fault and 8 sampling points after the fault are selected as sample data Perform PCA cluster analysis. The cluster centers of "line fault", "inverter side fault" and "rectifier side fault" are respectively formed, and the projection values ​​(q'1, q'2) of the polar line fault data on the PC1 and PC2 coordinates and the three types of fault current The distances d1, d2, and d3 between the centers of the curve clusters are used to determine the fault direction. For the positive line, when dmin=d1 or d2, it is judged as a forward fault; when dmin=d3, it is judged as a reverse fault. The protection criterion of the invention is constructed by calculating the minimum value of the Euclidean distance, which is accurate, reliable, simple and easy to implement.

Description

technical field [0001] The invention relates to a longitudinal protection method of an ultra-high voltage direct current line by using the principal component analysis of the pole line fault current curve cluster, and belongs to the technical field of electric power system relay protection. Background technique [0002] Compared with AC transmission lines, the control characteristics of DC transmission lines are complex, and the transient process after the line fault contains rich harmonic components. There is no power frequency in the form of DC transmission. The traditional AC line protection is obviously no longer suitable for DC lines. Be applicable. Therefore, the detection of UHV DC line faults cannot be judged solely by the magnitude of the fault current, but needs to be identified by fault voltage, current transient components, or a combination of the two. At present, UHV DC line protection mainly includes: DC line traveling wave protection, DC line differential und...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02H7/26G01R31/08
Inventor 束洪春吕蕾田鑫萃
Owner KUNMING UNIV OF SCI & TECH
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