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Comparison type directional protection method for travelling wave polarity by utilizing crossing sequence differential transformation

A differential conversion and directional protection technology, applied in the field of power system relay protection, can solve problems such as the influence of current transformer saturation

Inactive Publication Date: 2015-05-27
KUNMING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] The technical problem to be solved by the present invention is to judge the initial traveling wave polarity of the fault current and voltage after SOD transformation on the fault current and voltage, which overcomes the shortcomings of the traditional power frequency protection being affected by the distributed capacitance of the line and the saturation of the current transformer

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  • Comparison type directional protection method for travelling wave polarity by utilizing crossing sequence differential transformation
  • Comparison type directional protection method for travelling wave polarity by utilizing crossing sequence differential transformation
  • Comparison type directional protection method for travelling wave polarity by utilizing crossing sequence differential transformation

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Embodiment 1

[0074] Example 1: In figure 1 In the simulation system shown, the sampling frequency is 1MHz, the wave impedance is 236.69Ω, the initial fault phase angle is 90°, and the transition resistance is 5Ω. When a single-phase ground fault occurs at point F1 in the positive direction, the traveling wave device located at the M end of the line extracts the traveling wave voltage and current, as figure 2 shown. After phase-mode transformation is performed on the extracted transient traveling wave voltage and current, the line-mode voltage and line-mode current are obtained as image 3 shown. SOD transformation is performed on the obtained line-mode voltage and line-mode current to obtain the result as Figure 4 shown. Bringing the SOD transformation results of voltage and current into the polarity discriminant calculation, the result can be obtained as Figure 8 (a) shown.

[0075] Similarly, according to the above steps and implementation methods, we can finally get the final r...

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Abstract

The invention provides a comparison type directional protection method for travelling wave polarity by utilizing crossing sequence differential transformation, and belongs to the field of power system relay protection. The directional protection method comprises the following steps: when a power transmission line breaks down, extracting signals of a failure voltage and a failure current by a protecting and measuring device; performing the crossing sequence differential transformation on the extracted travelling wave signals so as to obtain a transformation quantity of the crossing sequence differential transformation of the failure voltage and the failure current; distinguishing a positive direction failure and an opposite direction failure by utilizing a discriminant of the comparison type directional protection method for the travelling wave polarity. According to the invention, a faulted travelling wave is detected by utilizing an algorithm of the crossing sequence differential transformation, so that although an interference signal is amplified, the interference information is restrained to a certain extent as compared with the amplification effect of failure information.

Description

technical field [0001] The invention relates to a traveling wave polarity comparison directional protection method using cross sequence differential transformation, and belongs to the technical field of electric power system relay protection. Background technique [0002] Power frequency line protection has experienced a century of application development, and it still plays a leading role in the field of power system relay protection. Although relay protection researchers have continuously developed and perfected traditional relay protection for decades, its basic principle has not changed. It still uses the fault power frequency component after a fault to identify faults. With the continuous construction of ultra-high voltage and ultra-high voltage transmission lines, the continuous operation of large-capacity units, and the interconnection of power grids, these have put forward higher requirements for relay protection of power systems. After the line fault, quickly and r...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R31/08
Inventor 束洪春李嫣然郑韵如董俊
Owner KUNMING UNIV OF SCI & TECH
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