DC line breakage protection method of multi-end flexible DC power distribution system

Abstract

The invention discloses a DC line breakage protection method of a multi-end flexible DC power distribution system. With regard to different running modes of open loop and closed loop of the multi-endflexible DC power distribution system, the fault characteristic thereof during a DC line breakage fault is analyzed, on the basis, the difference between the fault level and the non-fault level is further amplified by taking sum and difference of currents of a fault level circuit and a non-fault level circuit as division, and the purpose of reliably identifying the fault level circuit is achieved.The DC line breakage protection method is applicable to a condition that the DC line breakage fault occurs in the multi-end flexible DC power distribution system under different running mode, the situation that line breakage protection is difficult to achieve due to unobvious line breakage fault characteristic is prevented, and rapid fault identification and pole selection can be achieved according to local measurement information.

Description

technical field [0001] The invention relates to the technical field of control and protection of a flexible DC power distribution system, in particular to a DC disconnection protection method for a multi-terminal flexible DC power distribution system. Background technique [0002] Research on flexible DC power distribution systems is attracting widespread attention at home and abroad. Compared with AC power distribution systems, DC power distribution systems have stronger flexibility and can better adapt to multi-point connection of distributed power sources such as photovoltaics and DC loads. It has large transmission capacity, excellent power quality, and low commutation loss, which is one of the development trends in the field of power distribution in the future. However, the lack of mature line protection technology is one of the important factors that limit the wide application of DC power distribution systems, so it is of great significance to study fast and reliable f...

AI Technical Summary

Problems solved by technology

Compared with short-circuit faults with fault impulse current characteristics, unipolar disconnection has become a difficult point in protection research due to inconspicuous fault characteristics, and there are few targeted studies. The existing unipolar disconnection protection relies on single electrical quantity measurement , it is difficult to accurately and reliably identify the faulty line through setting the value

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