LC buffer current-limiting circuit-based hybrid DC circuit breaker

Abstract

The invention relates to the field of power electronics, and aims to provide an LC buffer current-limiting circuit-based hybrid DC circuit breaker. The circuit breaker comprises two parts comprising an auxiliary branch and a main branch in parallel, wherein an auxiliary DC switch and a main DC switch are respectively arranged, the auxiliary DC switch comprises a rapid isolation switch and an IGBT valve group which are connected in series, the main DC switch comprises an IGBT valve group and a metal oxide lightning arrester which are connected in parallel, an LC buffer current-limiting circuit is arranged in series in the main branch, and in the structure of the LC buffer current-limiting circuit, a buffer capacitor is connected in parallel with the metal oxide lightning arrester, is connected in series with a thyristor reversely connected in parallel and is finally connected in parallel with a current-limiting inductor to form the LC buffer current-limiting circuit. The LC buffer current-limiting loop is employed, fault current rising can be effectively limited, the open-circuit circuit is reduced, the MOA energy consumption is reduced, and the fault circuit removal speed is accelerated; and by employing a half-control device thyristor, the numbers of full-control device IGBTs are reduced, so that the control difficulty and the system cost are reduced, and the circuit breaker is reasonable in design, low in cost and high in reliability.

Description

technical field [0001] The invention belongs to the field of power electronics, in particular to a hybrid DC circuit breaker (DCCB) based on an LC buffer current limiting circuit. Background technique [0002] After the emergence of flexible DC transmission technology (VSC-HVDC), the construction of flexible DC grid has gradually become a new development direction in the power industry. After more than 10 years of research and development, the voltage source converter (VSC) has been widely used in asynchronous grid interconnection, distributed energy access, island power supply and other occasions, and has become the basis and core of flexible DC grid technology. Nowadays, the modular multilevel converter (MMC) has been used in many flexible DC power grid projects at home and abroad, and has become the most valuable topology in this field. [0003] In the flexible DC grid composed of MMC converter stations, how to deal with short-circuit faults (including single-pole ground...

AI Technical Summary

Problems solved by technology

However, the current hybrid circuit breakers require a large number of IGBTs connected in series and parallel, which not only increases the difficulty of voltage and current equalization control, but also greatly increases the cost and volume of the circuit breaker. In addition, many current hybrid DC circuit breakers do not have limited flow capacity, which limits the application of circuit breakers in multi-terminal DC grids, and the actual breaking of the fault current is under great pressure

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