Method for protecting double-end direct current distribution network

Abstract

The invention discloses a method for protecting a double-end direct current distribution network. The method comprises the steps of: 1) performing regional division on the double-end direct current distribution network by using a direct current circuit breaker and a direct current bus; 2) when the direct current distribution network has a single-pole ground or double-pole short-circuit fault, judging the fault current direction in each divided region; 3) performing information interaction on the fault current direction in each region, thus distinguishing the fault type; and 4) removing the fault according to the fault type. The line of the direct current distribution network is short, and the information interaction is only performed in the adjacent regions, so that the influence of delay on data transmission can be ignored; only digital signals are transmitted, so that the transmission time can be nearly ignored; the current direction is changed on the millisecond level, and the fault is removed by using the solid direct current circuit breaker, so that the operation speed is high, and quick protection of the double-end direct current distribution network can be realized; and the scheme has certain transition resistance tolerance, and is thus universal for protection of double-end direct current distribution networks.

Description

technical field [0001] The invention relates to the field of DC distribution network protection, in particular to a protection method for a double-terminal DC distribution network. Background technique [0002] In recent years, the rapid development and construction of cities has expanded the power supply radius of traditional AC distribution networks, which has brought about a series of problems such as tight power supply corridors and insufficient power supply in urban centers. On the other hand, the power supply and load have also undergone significant changes. The proportion of distributed power supply and DC load is getting higher and higher, but connecting to the AC distribution network through a DC / AC converter will not only affect the power quality and reduce the efficiency of power use , will increase additional investment and construction costs. The development of power electronics technology and flexible commutation technology has led to the rise of DC microgrid ...

AI Technical Summary

Problems solved by technology

Traditional AC distribution network protection schemes such as overcurrent, voltage, differential protection, etc. have poor applicability in DC distribution network, especially double-terminal or multi-terminal DC distribution network due to selectivity and setting problems, and the application of distance protection is limited. Due to the limitation of the algorithm, the differential protection is greatly affected by data synchronization when the fault current changes at a high rate

It can be seen that the traditional AC distribution network protection scheme has poor applicability to the DC distribution network, and it is necessary to study the protection scheme suitable for the DC distribution network

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