A kind of DC circuit breaker and using method thereof

Abstract

The invention discloses a DC circuit breaker and a using method thereof. The DC circuit breaker comprises a main conduction branch MC, a main break branch MB, an energy absorption branch EA and an auxiliary branch, wherein the main conduction branch MC is formed by a fast mechanical switch FD and a load current switch LCS in series connection; the main break branch MB is parallelly connected withthe main conduction branch MC and comprises an outer diode rectifier bridge and an inner half-control device-based bridge circuit; the energy absorption branch EA comprises a half-control device-basedfast discharge branch EA1 and a lightning arrester voltage limiting branch EA2; and the auxiliary branch is formed by an auxiliary resistor Raux and an auxiliary switch Sw in series connection. The DC circuit breaker can realize fast reclosing and fast cutting of small current, and has the advantages of large shutdown capacity and fast cutting speed.

Description

Technical field [0001] The invention relates to the field of DC circuit breakers, in particular to a DC circuit breaker and a method of use thereof. Background technique [0002] The flexible DC transmission technology based on modular multilevel converter (MMC) has broad application prospects in large-scale distributed energy grid connection, asynchronous grid interconnection, and urban DC transmission and distribution. However, the DC fault current of the DC grid has a fast rising speed and large amplitude, which puts forward higher requirements for the protection technology of the DC system. The fault clearing technology based on the DC circuit breaker can quickly isolate the fault and ensure the normal operation of the non-faulty part of the system. [0003] Current DC circuit breakers can be mainly divided into DC circuit breakers based on full control devices and DC circuit breakers based on semi-control devices. The DC circuit breaker based on the full control device utili...

AI Technical Summary

Problems solved by technology

However, the additional capacitor pre-charging power supply will increase the complexity and cost of the circuit breaker; the fault current will charge the capacitor to the system protection voltage during the shutdown process, which causes some DC circuit breakers based on semi-controlled devices to fail when cutting small currents. The cut-off time is greatly increased; the polarity of the capacitor voltage after the shutdown is completed is opposite to that before the shutdown. In order to restore the shutdown capability of the circuit breaker, some DC circuit breakers based on semi-controlled devices need additional capacitor voltage recovery time, which leads to Difficult to achieve fast reclosing

Images