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A half-wavelength transmission line protection method based on wave characteristic impedance

A characteristic impedance, transmission line technology, applied in emergency protection circuit devices, electrical components, fault detection according to conductor type, etc., can solve the problem of incomplete half-wavelength AC transmission line protection methods, etc., and achieve the effect of clear selectivity

Active Publication Date: 2021-01-05
TIANJIN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In short, the protection method of half-wavelength AC transmission lines is not yet perfect, and it is necessary to carry out in-depth research on it

Method used

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  • A half-wavelength transmission line protection method based on wave characteristic impedance
  • A half-wavelength transmission line protection method based on wave characteristic impedance
  • A half-wavelength transmission line protection method based on wave characteristic impedance

Examples

Experimental program
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Embodiment Construction

[0031] figure 1 is a single-phase uniform transmission line mn with length l, Z 0 =R 0 +jωL 0 and Y 0 =G 0 +jωC 0 It is the impedance and admittance per unit length, ω is the power frequency, and the positive direction of the current on the line is defined as from left to right. Assuming that the distance between point p on the line and the head end m is x, according to the transmission equation of the transmission line, the power frequency voltage of point p and current and power frequency voltage at point m and current satisfy the following relationship

[0032]

[0033] in, is the wave impedance, representing the relationship between the voltage traveling wave and the current traveling wave; is the propagation constant, α represents the amplitude attenuation, and β represents the phase shift. Solve formula (1) to get

[0034]

[0035] In the formula,

[0036]

[0037]

[0038] and It is called forward traveling wave and reverse traveling ...

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Abstract

The invention relates to a half-wavelength transmission line protection method based on wave characteristic impedance. The method constructs forward wave characteristic impedance and reverse wave characteristic impedance based on attenuation characteristics of the head-end voltage and the head-end and tail-end differential current of fault components, and determines the fault direction by using the characteristics and the difference of the two impedances when the internal and external faults of the half-wavelength transmission line occur.

Description

technical field [0001] The invention relates to the field of power system protection, in particular to a half-wavelength transmission line protection method based on wave characteristic impedance. Background technique [0002] Half-wavelength AC power transmission refers to the ultra-long-distance three-phase AC power transmission technology whose electrical distance of power transmission is close to a power frequency half-wave, that is, 3000km (50Hz) or 2500km (60Hz). The concept of half-wavelength AC power transmission was first proposed by Soviet experts in 1940, but limited to the level of technology at that time, some key technologies were difficult to solve, so no further research was carried out. [1] . With the increasing shortage of global energy resources, the international demand for high-power, ultra-long-distance power transmission has intensified. Therefore, half-wavelength AC power transmission has once again attracted the attention of many countries in recent...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02H7/26G01R31/08
CPCG01R31/085H02H7/265
Inventor 张艳霞常雨晴
Owner TIANJIN UNIV