Full-solidity direct-current breaker and control method thereof

Abstract

The invention provides a full-solidity direct-current breaker and a control method of the full-solidity direct-current breaker. A topological structure of the direct-current breaker comprises a current conversion branch circuit, a current breaking branch circuit, an energy absorbing branch circuit and a residual current isolating switch, wherein the current conversion branch circuit is composed of a voltage bearing switch and a current conversion switch connected with the voltage bearing switch in series, the current breaking branch circuit is connected with the current conversion branch circuit in parallel, the current conversion branch circuit is connected with the energy absorbing branch circuit in parallel, the residual current isolating switch, the current conversion branch circuit, the current breaking branch circuit and the energy absorbing branch circuit are connected in series in a main loop of an electric transmission line, and the current conversion branch circuit, the current breaking branch circuit and the energy absorbing branch circuit are connected in parallel. The topological structure of the direct-current breaker is novel and simple and achieves complete functions, the control method is simple, the function of short circuit current non-arc rapid disconnecting can be achieved, the voltage bearing switch, the current conversion switch and a current braking switch can be connected in series or in parallel through power electronic devices to achieve modularization, the requirement for consistency of the power electronic devices is lowered, and in-series use is achieved easily.

Description

technical field [0001] The invention belongs to the technical field of power electronics, and in particular relates to a topological structure and a control method of an all-solid-state DC circuit breaker. Background technique [0002] High-voltage direct current transmission technology has attracted more and more attention at home and abroad because of its characteristics of low line cost, high active power, and fast adjustment speed. In addition, the development of multi-terminal flexible DC transmission technology provides an effective solution to the inherent dispersion, small size, and distance from the load center of renewable clean energy such as wind energy and solar energy. The DC circuit breaker is one of the key equipment to improve the high-voltage DC transmission technology and multi-terminal flexible DC transmission technology to ensure the safe and reliable operation of the DC transmission system. [0003] In the AC system, the AC current has two natural zero...

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Problems solved by technology

[0003] In the AC system, the AC current has two natural zero-crossing points in one cycle, and the AC circuit breaker can use the natural zero-crossing points of the current to realize current shutdown; while in the DC system, since the DC current does not have a natural zero-crossing point, it cannot Eliminate high-voltage DC arc, so the breaking of DC current is much more difficult than that of AC current

[0004] At present, there are mainly three ways to break DC current. One is to add auxiliary circuits on the basis of conventional AC mechanical circuit breakers to artificially create a "zero-crossing point" similar to that in the AC system to break the circuit. The mechanical circuit breaker manufactured by the principle has a long breaking time and limited life, and usually cannot meet the requirements of the DC transmission system; one is to use high-power semiconductor devices to directly break the DC current. The solid-state circuit breaker manufactured by this principle, although The breaking time is short and there is no arc, but the on-state loss is too large and the cost is high; while the latest hybrid structure of mechanical switch and semiconductor switch combines the advantages of small conduction voltage drop of mechanical switch and fast breaking speed of semiconductor switch , but due to the existence of mechanical switches in the hybrid structure, the opening and closing speeds are still not fast enough

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