High-voltage direct-current transmission line protection method based on trigger angle control characteristic

Abstract

The invention discloses an extra-high-voltage direct-current transmission line protection method based on a trigger angle control characteristic. According to the method, an extra-high-voltage direct-current control system is analyzed; and by utilizing the inconsistency between change trends in a positive direction fault and change trends in a negative direction fault for a trigger delay angle ofa rectification side and a trigger advance angle of an inversion side, protective criteria are created; and a new protective principle is formed on the basis of interactive judgment of judgment information of the two sides. When a line has an internal fault, the trigger angles of the rectification side and the inversion side are increased; and the trigger angle of at least one side is reduced whenthe line has an external fault. Based on the difference, the criteria are created. The two sides exchange state information of protective criterion actions; and the fault is determined on the basis of the judgment of the state information of the two sides. The protection method is concise in principle, easy to set, high in sensitivity and capable of rapidly identifying the internal and external faults; and the communication content of the method is a state quantity, which is high in reliability and easy for engineering realization.

Description

Technical field [0001] The invention relates to the field of UHV DC transmission line relay protection, in particular to a high-voltage DC transmission line protection method based on trigger angle control characteristics. Background technique [0002] Compared with AC transmission, DC transmission has many advantages such as low line cost, narrow line corridor, large transmission capacity, low line active power loss, easy power adjustment, and convenient grid interconnection. However, the operating data shows the action of relay protection of UHV DC transmission lines Low accuracy rate (Song Guobing, Gao Shuping, Cai Xinlei, Zhang Jiankang, Rao Jing, Suonan Jiale. Overview of relay protection technology for HVDC transmission lines[J].Automation of Electric Power Systems,2012,36(22):123-129. ). The longitudinal differential protection of the UHV DC line is affected by the distributed capacitance of the line, so the protection criterion needs to be established after the transient...

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Problems solved by technology

[0002] Compared with AC transmission, DC transmission has many advantages such as low line cost, narrow line corridor, large transmission capacity, small line active power loss, easy power regulation, and convenient grid interconnection. The correct rate is low (Song Guobing, Gao Shuping, Cai Xinlei, Zhang Jiankang, Rao Jing, Suonan Jiale. A review of relay protection technology for HVDC transmission lines[J]. Automation of Electric Power Systems, 2012,36(22):123-129. )

Due to the influence of line distributed capacitance, the longitudinal differential protection of UHV DC lines needs to wait for the transient process to end before the protection criterion is established, the action time is slightly longer, and the sensitivity is not high

In order to solve the above problems, some innovative achievements have appeared (Guo Liang, Xiong Huaqiang, Wang Guannan, Gui Xiaozhi, Pan Benren. A differential protection method for long-distance UHV DC transmission lines: Chinese Invention Patent, 201510255701.4 [P ].2018-01-09.), achieved certain results, but the synchronization of protection on both sides is still relatively high

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