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Cable hybrid DC line fault distance measurement method and system based on single-end and double-end distance measurement

A hybrid DC and line fault technology, applied in the direction of fault location, etc., can solve the problems of low reliability and accuracy, influence of distance measurement accuracy, non-uniform line wave impedance, etc., and achieve strong ability to withstand transition resistance and small amount of calculation , The effect of high ranging accuracy

Pending Publication Date: 2022-05-13
SHANDONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

From the perspective of space, time and frequency, fault location methods for DC transmission lines are mainly divided into: traveling wave method, fault analysis method and natural frequency method. However, the distance measurement using the traveling wave method has a strong dependence on the accurate calibration of the traveling wave head, the transition resistance directly affects the accurate calibration of the traveling wave head, and the selection of the traveling wave velocity will also affect the ranging accuracy
[0004] For DC transmission lines with mixed cables, the wave impedance of the line is not uniform, and it is necessary to consider the complex situation of refraction and reflection caused by the difference in wave impedance between overhead lines and cables. The inventors found that the traditional single-line fault location method is no longer applicable, and Existing fault location algorithms for hybrid HVDC transmission lines all have problems of low reliability and accuracy

Method used

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  • Cable hybrid DC line fault distance measurement method and system based on single-end and double-end distance measurement
  • Cable hybrid DC line fault distance measurement method and system based on single-end and double-end distance measurement
  • Cable hybrid DC line fault distance measurement method and system based on single-end and double-end distance measurement

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Embodiment 1

[0052] refer to figure 1 , the present embodiment provides a cable hybrid DC line fault location method based on single- and double-ended ranging, which specifically includes the following steps:

[0053] S101: Obtain fault current traveling wave signals at both ends of the line in the fault section where cables are mixed.

[0054] Such as figure 2 As shown, the fault location model of this embodiment includes a rectifier side, an inverter side and a DC hybrid line. The DC hybrid line is connected between the rectifier side and the inverter side, and consists of two sections of transmission lines, the section near the rectification side is an overhead line, and the section near the inverter side is a cable line. Install electrical quantity acquisition devices near the rectifier side, near the inverter side, and overhead line-cable connections.

[0055] The fault current traveling wave signal in this embodiment includes fault current traveling wave signals on the positive a...

Embodiment 2

[0123] This embodiment provides a cable hybrid DC line fault location system based on single- and double-ended ranging, which specifically includes the following modules:

[0124] A traveling wave signal acquisition module, which is used to acquire the fault current traveling wave signals at both ends of the cable mixed fault section line;

[0125] A line mode component signal extraction module, which is used to extract the line mode component signal from the fault current traveling wave signal;

[0126] A current mutation moment determination module, which is used to perform multi-resolution morphological gradient analysis on the line mode component signal to determine the current mutation moment;

[0127] A fault point position determination module, which is used to determine the fault point position based on the current sudden change moment and the selected ranging formula;

[0128] Based on the refraction and reflection of the fault current traveling wave, calculate its r...

Embodiment 3

[0137] This embodiment provides a computer-readable storage medium, on which a computer program is stored. When the program is executed by a processor, the method for fault location of a cable hybrid DC line based on single- and double-ended distance measurement as described above is implemented. A step of.

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Abstract

The invention belongs to the technical field of power system line protection, and provides a cable hybrid DC line fault distance measurement method and system based on single-end and double-end distance measurement. The method comprises the following steps: acquiring fault current traveling wave signals at two ends of a fault section line with mixed cables; extracting a line mode component signal from the fault current traveling wave signal; performing multi-resolution morphological gradient analysis on the line mode component signal to determine a current sudden change moment; determining the position of a fault point based on the current abrupt change moment and a selected distance measurement formula; wherein the selection principle of the distance measurement formula is that the refraction and reflection coefficient of the fault current traveling wave is calculated based on the refraction and reflection condition of the fault current traveling wave, and the distance measurement formula which is obtained through analysis and contains the moment corresponding to the wave head with the maximum wave head amplitude is selected; the two groups of single-end and double-end fault distance measurement formulas are obtained according to the distance between a fault point and one end of a fault section line and by combining a single-end traveling wave distance measurement principle and a double-end traveling wave distance measurement principle, and each group of fault distance measurement formulas comprises two fault distance measurement formulas.

Description

technical field [0001] The invention belongs to the technical field of power system line protection, and in particular relates to a cable hybrid DC line fault distance measurement method and system based on single- and double-terminal distance measurement. Background technique [0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art. [0003] Compared with the AC transmission system, the DC transmission system has the advantages of small line loss, large transmission energy, simple and flexible structure, and easy interconnection of different power grids. The DC transmission line has a wide span, and the geographical environment along the line is complex and changeable. The DC transmission line may use a mixed connection method of overhead lines and cables. From the perspective of space, time and frequency, fault location methods for DC transmission lines are mainly divided int...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R31/08
CPCG01R31/08
Inventor 高湛军杨涛于成澳刘朝
Owner SHANDONG UNIV
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