Protection device and protection method for suppressing DC bus support capacitor short circuit

Abstract

The invention discloses a protection device and a protection method for suppressing short circuit of a DC bus support capacitor. The protection device comprises a bidirectional solid-state circuit breaker, and the bidirectional solid-state circuit breaker is arranged in a branch of the DC bus capacitor bank; the bidirectional solid-state circuit breaker is connected in series with a capacitor bankin a VSC; the bidirectional solid-state circuit breaker comprises a bidirectional switch, a current-limiting resistor R and a controller, wherein the bidirectional switch is formed by connecting a set of forward solid-state switches and a set of reverse solid-state switches in series, the current-limiting resistor R is connected to the two sides of the forward solid-state switches in parallel, and each of the set of forward solid-state switches and the set of reverse solid-state switches is composed of IGBT anti-parallel power diodes. The protection device can meet the requirement of quicklycutting off fault current, reduces the current stress and design requirements of a main loop, can achieve arc-free breaking, is simple and reliable, is low in cost, is easy to operate, and is completein function.

Description

technical field [0001] The invention relates to a protection device and a protection method for suppressing a short-circuit of a DC bus supporting capacitor, and belongs to the fields of power switch technology and power system protection. Background technique [0002] In recent years, the application of DC power system has continued to expand, which is a beneficial supplement to the existing AC power system and can achieve better performance of the system. For example, HVDC transmission can make better use of its economical and flexible transmission and control characteristics; medium-voltage DC system will improve the efficiency and power quality of the system. In addition, DC microgrids can better integrate distributed energy into smart grids. In the above DC system, it is essential to equip a voltage source converter (VSC). [0003] At present, there are a large number of DC bus support capacitors in VSC, and the discharge current of these capacitors plays an important...

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Problems solved by technology

[0009] The technical problem to be solved by the present invention is: the current circuit breaker has a large stress due to the rapid discharge of capacitive energy, the design capacity of the circuit breaker is large, the volume and weight are too large, and the cost is high

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