A Capacitor Charging Bidirectional DC Circuit Breaker and Its Application

Abstract

The invention discloses a capacitance-charging bidirectional direct-current breaker and an application thereof. The capacitance-charging bidirectional direct-current breaker comprises an auxiliary branch and a main branch which are connected in parallel, wherein a first mechanical switch and a power electronic device valve group are serially connected to form the auxiliary branch, and a single-phase uncontrollable rectifier bridge and a capacitance-mechanical switch capacitance serial branch are combined to form the main branch. The invention further discloses a direct-current breaker. Two capacitance serial branches of the identical structures are reversely connected in parallel to form the main branch, wherein one capacitance serial branch is formed by a mechanical switch, a direct-current capacitor and a diode valve group which are serially connected, the other capacitance serial branch is identical with the first capacitance serial branch in structure, and the wiring mode is opposite. The invention further discloses a control method for carrying out fault isolation and rapid reclosing on the direct-current breaker. According to the invention, the defect that the direct-current capacitance and line inductance of an existing direct-current breaker are liable to form inductance-capacitance oscillation is avoided, and the direct-current fault is cut off, the current is stable and reliable, and rapid reclosing is realized.

Description

technical field [0001] The invention belongs to the technical field of electric power transmission and distribution, and more specifically relates to a capacitor charging bidirectional DC circuit breaker and its application in DC fault isolation. Background technique [0002] With the development of modular multilevel converters, the use of modular multilevel converters to construct DC power grids has become a hot spot in the power industry in recent years. The DC power grid needs to interconnect the DC transmission lines on the DC side. When a DC fault occurs, it is necessary to quickly isolate the faulty line to avoid the voltage collapse of the DC grid. For this reason, the DC circuit breaker is an indispensable device for large-scale DC power grids. [0003] The solid-state switching DC circuit breaker is a typical DC circuit breaker, which is composed of a large number of fully-controlled power electronic devices in series. This DC circuit breaker can break the DC fault...

AI Technical Summary

Problems solved by technology

[0007] However, in this scheme, since the DC fault current can only charge DC in one direction, it can only isolate the DC fault on the line side of the DC circuit breaker, and there is a problem that it cannot isolate the DC fault on the DC bus side, and it cannot be connected to the same DC bus. backup protection for other DC lines of the

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