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Time difference method based adaptive half wavelength line differential protection method

A line differential and half-wavelength technology, which is applied to automatic disconnection emergency protection devices, emergency protection circuit devices, circuit devices, etc., can solve the problem that the capacitive current compensation method is no longer applicable, and the voltage difference of half-wavelength transmission lines cannot be ignored, etc. question

Active Publication Date: 2016-05-11
CHINA ELECTRIC POWER RES INST +2
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Problems solved by technology

[0003] Current differential protection is widely used as the main protection of medium-length AC transmission lines, but the voltage difference along the half-wavelength transmission line cannot be ignored, and the traditional capacitive current compensation method is no longer applicable. To solve this problem, the present invention proposes a An adaptive half-wavelength line differential protection method based on time difference method

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  • Time difference method based adaptive half wavelength line differential protection method
  • Time difference method based adaptive half wavelength line differential protection method
  • Time difference method based adaptive half wavelength line differential protection method

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Embodiment 1

[0032] The invention of this example proposes an adaptive half-wavelength line differential protection method based on the time difference method. The steps are as follows figure 1 Shown:

[0033] (1) The action time of the protection starting element of the time difference method is the time when the protection element senses the occurrence of the fault. The action time T of the protection starting element on both sides of the line can be obtained M , T N . Time difference law protection start criterion:

[0034] Δ f ( t ) = Δi A 2 ( t ) + Δi B 2 ( t ) + Δi C 2 ( t ) | d Δ f ( t ) | > f s e t = ( 0.3 k A ) 2 = 0.1 kA 2 - - - ( 1 )

[0035] (2) Using the time difference method to estimate the fault location L FM :

[0036] L FM =((T M -T N )v Light +L)2(2)

[0037] (3) Take the fault point L FM To compensate the point, use the...

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Abstract

The invention relates to a time difference method based adaptive half wavelength line differential protection method. As the electric distance of half wavelength power transmission is long, obvious actuation time difference between protective starting elements at two sides of the line exists after faults occur. According to the wave transmission principle, the position of a fault point can be estimated according to the actuation time difference of the protective starting elements at two sides of the line. Voltage and current of the protective installation positions at two sides of the line can be compensated to the fault point according to a long line equation, so as to obtain a current value of the fault point, and then differential current is calculated. Sensitivities for fault differential protection criterions of different points of the line are different, and brake coefficients and threshold values of differential protection are changed according to different adaptions of the fault point positions, so as to ensure that differential protection has sensitivity for the whole line.

Description

Technical field: [0001] The invention relates to the field of relay protection, and more particularly to an adaptive half-wavelength line differential protection method based on the time difference method. Background technique: [0002] Half Wavelength AC Transmission (HWACT) refers to a three-phase AC transmission with an electrical distance close to a power frequency half wave, that is, 3000 kilometers (50 cycles) or 2600 kilometers (60 cycles). Compared with medium-length (hundreds of kilometers) AC transmission, this ultra-long-distance AC transmission has some distinct characteristics and significant advantages, such as no need to install reactive power compensation equipment; no need to set up an intermediate switch station; overvoltage level Not high; excellent economy, etc. To realize the engineering application of half-wave transmission, further research is needed on the relay protection technology of the line. [0003] Current differential protection is widely used as t...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02H7/26H02H7/22G01R31/08
CPCG01R31/085G01R31/088H02H7/226H02H7/263H02H3/042H02H3/305
Inventor 梁旭明郭雅蓉柳焕章李肖周泽昕杜丁香王德林李晶李会新李仲青
Owner CHINA ELECTRIC POWER RES INST
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