A backup protection method and device for a high-voltage direct current transmission line

Abstract

The invention discloses a backup protection method and device for a high-voltage direct current transmission line. The method comprises the following steps: collecting current information of a relay protection device installed on both sides of the high-voltage direct current transmission line; filtering the sampled current information by a low-pass filter to obtain a filtered current sampling value; and filtering the sampled current information by a low-pass filter. Using the filtered current value, the differential current of the positive and negative DC lines after filtering can be calculated. By comparing the difference current of the positive and negative DC lines after filtering with the minimum action current, the faults inside and outside the DC line can be determined. If the faultis located in the DC line protection area, the fault of the positive line, the negative line or the bipolar line can be determined by comparing the difference between the positive and negative filtered current values. The invention has the beneficial effects of simple criterion, fast operation speed and high reliability, and can respond to the high-resistance grounding fault of the DC line, and can solve the problem that the action speed of the backup protection of the DC line is too slow.

Description

technical field [0001] The invention belongs to the field of relay protection for power systems, and more specifically relates to a backup protection method and device for high-voltage direct current transmission lines. Background technique [0002] Compared with the traditional AC transmission system, the HVDC transmission system has the advantage of transmitting large-capacity electric energy with low loss, and is widely used in long-distance power transmission, asynchronous system networking, and DC cable power transmission. [0003] Fast and reliable DC transmission line protection is of great significance to the safe and stable operation of the DC transmission system and even the entire power system. However, there are still a series of problems in the current DC line protection system. The current DC transmission line protection system usually adopts the protection scheme of ABB and SIMENS, that is, the traveling wave protection and the differential undervoltage protec...

AI Technical Summary

Problems solved by technology

[0004] Aiming at the above defects or improvement needs of the prior art, the present invention provides a backup protection method and device for high-voltage direct current transmission lines, thereby solving the problem that the main protection of existing high-voltage direct current transmission lines is difficult to respond to high-impedance grounding faults, and the backup protection is aimed at The technical problem that the response speed of high resistance grounding fault is too slow

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