A combined high-voltage DC circuit breaker with self-supply capability and its self-supply method

Abstract

The invention discloses a combined type high-voltage DC circuit breaker with a self-energizing ability, and a self-energizing strategy thereof. According to the combined type high-voltage DC circuit breaker and the self-energizing strategy thereof, a daily through-current branch of a traditional combined type high-voltage DC circuit breaker is improved, a load transfer switch is changed from the original mode of IGBT series connection to a mode of full-bridge submodule series connection, and the corresponding self-energizing strategy is designed, so that capacitors in submodules operate in an energized manner under normal working condition. The load transfer switch of the circuit breaker typology is energized by means of the capacitors of the submodules directly without the need of external power supply, the insurmountable insulation problem in engineering is avoided, and the application prospect of the circuit breaker in a high-voltage DC power grid can be improved.

Description

technical field [0001] The invention belongs to the technical field of power electronic systems, and in particular relates to a combined high-voltage direct current circuit breaker with self-supply capability and a self-supply method thereof. Background technique [0002] The DC fault self-clearing capability of the DC grid is an important technical problem related to the development prospect of the DC grid. Compared with traditional AC transmission, there are two main technical difficulties in the development of high-voltage DC circuit breakers suitable for DC grids: (1) The damping of DC grids is low, and its fault development speed is faster, which poses a problem for the operating speed of circuit breakers. Higher requirements; (2) Since the DC transmission has no current zero crossing point, its fault arc is more difficult to extinguish. At present, the research programs of high-voltage DC circuit breakers mainly focus on three types, namely, traditional mechanical cir...

AI Technical Summary

Problems solved by technology

Aiming at the problems existing in the prior art, the Chinese patent with the publication number CN104767185A proposes a combined high-voltage DC circuit breaker suitable for DC grids. The circuit breaker refers to the design concept of the hybrid high-voltage DC circuit breaker, and its The main components have been reconfigured and improved, especially suitable for DC grid systems with complex grid structures

[0005] At present, regardless of the hybrid high-voltage DC circuit breaker or the combined high-voltage DC circuit breaker, it cannot operate successfully in the high-voltage field, such as a DC power grid with a DC voltage of 500kV. The fundamental reason is that the current project uses external power supply. , to supply energy for the drive circuit of the IGBT in the circuit breaker, but since the circuit breaker needs to be connected in series in the DC line, and the DC voltage level is relatively high, higher requirements are placed on the insulation and withstand voltage of the external power supply circuit. Unsatisfactory; this defect greatly limits the application of DC circuit breakers in the field of high voltage technology

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