Capacitive commutation hybrid fault current limiter and control method thereof

Abstract

The invention provides a capacitive commutation hybrid fault current limiter and a control method thereof. The capacitive commutation hybrid fault current limiter comprises an on-state low-loss branch, a current transfer branch and a current limiting branch. A semi-controlled device is simple in logic and economical and reliable. The hybrid fault current limiter is low in loss of the steady state,has a bidirectional current limiting capability and can effectively inhibit the short-circuit current of a DC grid; the locking time of a sub module IGBT is delayed to obtain enough time for motion of other protection devices; it is ensured that a current limiting resistor and a corresponding heat-dissipating device can be fully utilized to improve the current limiting effect. The control methodof the capacitive commutation hybrid fault current limiter comprises two conditions of the normal operation of the DC line where the current limiter is located or before detection of the generation offaults of the DC line where the current limiter is located or after detection of the generation of faults of the DC line where the capacitive commutation hybrid fault current limiter is located to achieve control for a resistance-inductive capacitor commutation hybrid current limiter.

Description

technical field [0001] The invention relates to the technical field of power electronics, in particular to a capacitive commutation hybrid fault current limiter and a control method thereof. Background technique [0002] High-voltage and large-capacity DC grid technology is an important link in the future construction of smart grids and global energy Internet. Flexible DC transmission technology based on modular multilevel converter (MMC) facilitates the construction of DC power grids, thus becoming a new expectation in the power industry. The Zhangbei DC power grid to be built in my country adopts the half bridge sub module plus overhead line scheme, which is the world's first DC power grid engineering practice. The use of overhead lines has obvious technical and economic advantages, but the ensuing problem is the high probability of faults on the DC side. Combined with the fact that the half-bridge sub-module does not have the ability to clear faults on the DC side, it is...

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Problems solved by technology

[0005] In order to overcome the problems of large loss and poor economy of the solid-state DC current limiter in the above-mentioned prior art, as well as the high manufacturing cost and large equipment volume of the superconducting current limiter, the present invention provides a capacitor commutation hybrid fault current limiter and its Control method, capacitive commutation hybrid fault current limiter includes on-state low loss branch, current transfer branch and current limiting branch

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