Bidirectional DC circuit breaker and switching-on and switching-off method

Abstract

The invention discloses a bidirectional DC circuit breaker and a switching-on and switching-off method. The DC circuit breaker comprises a main loop, a commutation branch, an energy absorption branch, an on-line monitoring system and a control system, the main loop; the commutation branch and the energy absorption branch are connected in parallel and are led out through wire outlet ends L1 and L2; the main loop is formed by connecting one or more mechanical switches in series; the commutation branch is composed of a pre-charging capacitor, an oscillation inductor, an oscillation capacitor and a series-parallel power electronic power device; and the energy absorption branch is composed of a lightning arrester. According to the switching-on and switching-off method provided by the invention, when the micro-loss bidirectional DC circuit breaker with the reclosing function breaks the current, it can be ensured that the commutation branch generates the oscillating current with the amplitude gradually increased, the current is superposed on the current of the main loop to generate the current zero crossing point, and finally the current is broken by the mechanical switch. The DC circuit breaker has a reclosing function, realizes bidirectional through-flow, and realizes rapid breaking of current in a range from rated current to short-circuit current.

Description

technical field [0001] The invention belongs to the field of circuit breakers, in particular to a bidirectional DC circuit breaker and a breaking method. Background technique [0002] At present, DC circuit breakers mainly have two implementation methods: manual zero-crossing type DC circuit breaker and hybrid type DC circuit breaker. Among them, the artificial zero-crossing technology circuit breaker has become the preferred technical solution for DC circuit breakers due to its small on-state loss. With the substantial increase in the demand for distributed DC power supply systems of new energy, especially in flexible multi-terminal DC systems connected to new energy grids, since most loads have dual attributes of power generation and power consumption, this characteristic causes energy in the flexible multi-terminal DC grid The direction of the tide is uncertain. Moreover, flexible multi-terminal DC systems connected to new energy grids often contain a large number of pow...

AI Technical Summary

Problems solved by technology

However, traditional DC circuit breakers have problems such as large on-state loss and high cost, and cannot be applied to flexible multi-terminal DC systems.

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