Method and system for ratio braking pole selection of DC transmission line

Abstract

The invention provides a DC transmission line ratio braking pole selection method and system. The method and system determine the current differential value and the current mutation amount of the line by collecting the current of the direct current transmission line, and when the current differential value of the line meets the protection starting criterion, start the DC protection, and then determine the ratio control according to the current mutation amount Whether the dynamic current pole selection criterion is established, and finally determine whether the activated DC protection action is exported according to the judgment result. In the DC transmission line ratio brake pole selection method and system of the present invention, when a metallic or high-resistance fault occurs in a certain DC transmission line, the ratio brake current pole selection criterion of the fault pole is established, and the line protection operates instead of The pole selection criterion of fault pole ratio brake current is not established, and the non-fault pole line protection does not operate, which better solves the problem of misoperation of the non-fault pole line protection when the DC transmission line fails, and improves the performance of the DC transmission line protection .

Description

technical field [0001] The present invention relates to the field of relay protection of electric power systems, and more specifically, to a DC transmission line ratio brake pole selection method and system. Background technique [0002] Compared with the traditional AC transmission system, the HVDC transmission system has the advantages of large transmission capacity, long transmission distance, and low loss. It has been widely used in long-distance power transmission, large-area grid interconnection, and underground cable transmission. High-voltage direct current transmission lines shoulder the heavy responsibility of power transmission in energy production areas and load center time periods. The transmission distance is long, the operating conditions are harsh, and the failure rate is higher than other parts of the direct current system, accounting for about 50% of direct current system failures. Therefore, high-performance HVDC transmission line protection is of great si...

AI Technical Summary

Problems solved by technology

[0004] In order to solve the technical problem in the prior art that the protection of non-faulty poles in DC transmission lines is prone to misoperation due to the lack of highly reliable pole selection methods, the present invention provides a DC transmission line ratio braking pole selection method. The methods described include:

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