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Ultra-high-voltage direct-current transmission line single-end protective method

An ultra-high voltage DC and transmission line technology, applied in emergency protection circuit devices, electrical components, etc., can solve the problems of slow protection action, easy refusal to operate, low sensitivity of current differential protection, etc. The effect of protecting and guaranteeing quickness

Active Publication Date: 2015-04-22
KUNMING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Traveling wave protection and differential undervoltage protection tend to refuse to operate in case of high-impedance grounding fault, current differential protection has low sensitivity and slow protection action
[0003] Transient protection using boundary to high-frequency attenuation characteristics is the development direction of UHV DC transmission line protection. In recent years, scholars have studied transient protection using boundary to high-frequency quantity attenuation characteristics as a UHV DC transmission line protection method. Usually, the attenuation characteristics of UHV DC ultra-long transmission lines are not considered, so full-line protection in the true sense cannot be realized

Method used

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  • Ultra-high-voltage direct-current transmission line single-end protective method
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  • Ultra-high-voltage direct-current transmission line single-end protective method

Examples

Experimental program
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Effect test

Embodiment 1

[0035] Embodiment 1: as Figure 1-2 As shown in the figure, a single-ended protection method for UHV DC transmission lines, firstly use the data acquisition device to collect the fault current data in the time window 5 ms after the arrival of the first wave of the fault current traveling wave and calculate the 1-mode component; then the 1-mode component Subtract the 1-mode current in normal operation before the fault from the current signal to obtain the fault current variation and sum it, and then judge whether the signal comes from outside the rectifier side area or from outside the line or inverter side area according to the summation result; For the fault current signal from the line or outside the inverter side area, use the Hilbert-Huang transformation to obtain the maximum value of the instantaneous frequency, and then compare the maximum value of the instantaneous frequency with the preset threshold value to judge the fault Occurs on the line or outside the inverter si...

Embodiment 2

[0045] Embodiment 2: as Figure 1-2 As shown in the figure, a single-ended protection method for UHV DC transmission lines, firstly use the data acquisition device to collect the fault current data in the time window 5 ms after the arrival of the first wave of the fault current traveling wave and calculate the 1-mode component; then the 1-mode component Subtract the 1-mode current in normal operation before the fault from the current signal to obtain the fault current variation and sum it, and then judge whether the signal comes from outside the rectifier side area or from the line or inverter side area according to the summation result; For the fault current signal from the line or outside the inverter side area, use the Hilbert-Huang transformation to obtain the maximum value of the instantaneous frequency, and then compare the maximum value of the instantaneous frequency with the preset threshold value to judge the fault Occurs on the line or outside the inverter side area....

Embodiment 3

[0054] Embodiment 3: as Figure 1-2 As shown, a single-end protection method for UHV DC transmission lines, the specific steps of the method are as follows: a ground fault occurs on the positive busbar at the rectification side, and the transition resistance is 1 ohm. Collect the current on the two-pole lines in the window 5ms after the arrival of the first wave head of the fault traveling wave, and obtain the 1-mode component of the current; obtain the fault current variation Δi (where, in this example, i normal It is the value when the system is in full load and normal operation, the value is 6.25kA), and then use the formula to get the P value -148.8482, which is judged to be an out-of-area fault on the rectifier side, and the protection does not operate.

[0055] Because the sampling rate in the present invention is 10kHz, and the sampling time window is 5ms, the K value used is 50, which is the same in the following examples.

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Abstract

The invention relates to an ultra-high-voltage direct-current transmission line single-end protective method, and belongs to the technical field of high-voltage direct-current transmission system replay protection. The method includes the steps that firstly, a data acquisition device acquires the fault current data in a time window of 5 ms after a fault current travelling wave head wave head reaches, and a 1 model component is solved; then 1 model current which operates normally before fault is subtracted from a 1 model component current signal, the fault current variable quantity is obtained, summation operation is conducted on the fault current variable quantity, and whether the signal comes from the exterior of a rectification side region or from the exterior of a circuit or the exterior of a contravariant side region is judged according to the summation operation; Hilbert-Huang transform is conducted on the fault current signal from the exterior of the circuit or the exterior of the contravariant side region, the instantaneous frequency maximum value of the signal is obtained, the obtained instantaneous frequency maximum value is compared with the preset threshold value to judge whether the circuit or the exterior of the contravariant side region breaks down. By means of the ultra-high-voltage direct-current transmission line single-end protective method, the full-line protection of an ultra-high-voltage direct-current transmission line can be achieved, and the good speed can be guaranteed.

Description

technical field [0001] The invention relates to a single-end protection method for an ultra-high voltage direct current transmission line, belonging to the technical field of relay protection for high voltage direct current transmission systems. Background technique [0002] Currently, traveling wave protection is the main protection in DC line protection, with differential undervoltage protection and differential protection as backup protection. Traveling wave protection and differential undervoltage protection tend to refuse to operate when there is a high-impedance ground fault, and the sensitivity of current differential protection is not high, and the protection action is slow. [0003] Transient protection using boundary to high-frequency attenuation characteristics is the development direction of UHV DC transmission line protection. In recent years, scholars have studied transient protection using boundary to high-frequency quantity attenuation characteristics as UHV ...

Claims

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Application Information

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IPC IPC(8): H02H7/26
Inventor 陈仕龙张杰毕贵红谢佳伟李兴旺荣俊香曹蕊蕊
Owner KUNMING UNIV OF SCI & TECH
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