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Self-adaptive current differential protection method for direct-current lines

A DC line and current differential technology, which is applied in the direction of automatic disconnection emergency protection devices, emergency protection circuit devices, electrical components, etc., can solve the problems of slow protection action speed, easy misoperation, and low reliability

Active Publication Date: 2012-04-04
XI AN JIAOTONG UNIV
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AI Technical Summary

Problems solved by technology

[0004] The current differential protection has excellent performance and is the natural main protection in AC transmission lines. However, due to various reasons, its protection action speed is slow and the performance is not good in DC transmission lines.
Most of the DC lines in operation use traveling wave protection as the main protection. Traveling wave protection operates quickly and is not affected by factors such as transition resistance, load, and long-line distributed capacitance, but its reliability is not high and it is easy to malfunction

Method used

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  • Self-adaptive current differential protection method for direct-current lines
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  • Self-adaptive current differential protection method for direct-current lines

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Embodiment Construction

[0034] Attached below figure 1 The present invention will be described in further detail.

[0035] The DC transmission system consists of three parts: rectifier station, inverter station and DC transmission line. The rectifier station converts the alternating current to direct current, the transmission line transmits the direct current to the opposite inverter station, and the inverter station converts the direct current to alternating current. The core content of the invention is to provide protection for direct current transmission lines.

[0036] The present invention is an adaptive current differential protection method for a DC line, which is based on a time-domain distribution parameter model. The DC line is a two-terminal DC system or a T-connection three-terminal DC system; the two-terminal DC system includes N terminals and K terminal; the three-terminal DC system includes J terminal, K terminal and M terminal, specifically including the following steps:

[0037] 1) ...

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Abstract

The invention provides a self-adaptive current differential motion protection method for direct-current lines. The method is suitable for direct-current power transmission lines in two-end and multi-end direct-current power transmission systems. To the two-end system, setting-point currents are respectively calculated through electric quantities at two ends so as to realize the current differential protection; and to the multi-end system, branch-point currents are respectively calculated through the voltage and the current of a converter station line end so as to realize the current differential protection. A self-adaptive fault severity setting method is brought forward, and the self-adaptive adjustment of a differential current threshold is realized through the change of the voltage, so that the rapidity and the sensitivity of the protection are taken into account. The self-adaptive current differential protection method for the direct-current lines can improve the sensitivity and the reliability of the protection of direct-current lines and is suitable for the two-end and multi-end direct-current power transmission systems and a voltage source converter type direct-current power transmission system.

Description

【Technical field】 [0001] The invention relates to a relay protection method for a power system line, in particular to an adaptive current differential protection method for a DC transmission line. 【Background technique】 [0002] my country's energy resources and productivity are distributed in reverse, and large power bases are far away from the load center. In order to optimize the allocation of some high-quality power sources in the receiving end power market and strengthen the interconnection between power grids, double-terminal DC transmission and multi-terminal DC transmission have broad potential in my country. Application prospect. Therefore, improving the safety and reliability of DC transmission line operation has become an urgent problem to be solved. [0003] At present, most of the DC lines in operation use traveling wave protection as the main protection. Traveling wave protection has been widely used in DC transmission, but there is a problem of low reliability...

Claims

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Application Information

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IPC IPC(8): H02H7/26H02H3/26
Inventor 宋国兵高淑萍刘琪蔡新雷索南加乐
Owner XI AN JIAOTONG UNIV
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