Protection method for multilevel direct current distribution feeder line

Abstract

The invention discloses a protection method for a multilevel direct current distribution feeder line. The protection method is implemented according to the following steps specifically: step one, collecting the current ix(k) at the outlet of each level of direct current bus of the multilevel direct current distribution feeder line, and calculating a current increment measured value delta ix(k), wherein x is A, B, ..., M level, and k is the sampling number of the current at the outlet of each level of direct current bus; step two, judging the fault section of the multilevel direct current distribution feeder line; and step three, restarting a current converter. The protection method for the multilevel direct current distribution feeder line disclosed by the invention can be matched with the protection of the current converter, the fault section of the direct current feeder line can be identified correctly, a cutting fault is protected by a corresponding feeder line, and adjacent feeder lines are protected from operating falsely, so that the action selectivity of a direct current circuit breaker is guaranteed.

Description

technical field [0001] The invention belongs to the technical field of relay protection for DC distribution networks, and in particular relates to a protection method for multi-level DC distribution feeders. Background technique [0002] With the rapid growth of power load, the existing AC distribution network is increasingly limited by the power supply radius, especially the large number of applications of power electronic devices have injected a large number of harmonics into the AC distribution system, and the power quality of the AC distribution network has also been affected. severe impact. With the rapid development and wide application of high-voltage direct current transmission technology and flexible direct current technology, experts and scholars at home and abroad have proposed to conduct direct current power supply at the voltage level of power supply and distribution in recent years. Compared with the AC power distribution system, the DC power distribution syst...

AI Technical Summary

Problems solved by technology

[0004] The above protection schemes are mainly aimed at "single-stage" DC lines, but due to their special structures or uses, their line protection schemes are not traditional distribution feeder protection and have strong The particularity of the inverter, and most of them are aimed at only one DC line at the outlet side of the converter, and there are few T-connected loads or distributed power branches on this DC line

Therefore, these DC line protection schemes cannot be directly applied to the protection of "multi-level" feeders in DC power supply and distribution networks.

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