A DC vacuum circuit breaker

Abstract

The invention discloses a direct-current vacuum circuit breaker, which comprises a normal current branch, a conversion branch, an energy absorption branch and a magnetic field generating branch. The magnetic field generating branch is formed by sequential series connection of a drive capacitor C1, a repulsion coil L1 and a high-voltage cable L3 wound around an arc extinguishing chamber. A diode D1is parallelly connected to two sides of the L1 and the L3, and a stable and durable longitudinal magnetic field is generated in the arc extinguishing chamber through long-time follow current of the diode D1 by the repulsion coil L1 and the high-voltage cable L3 after discharging of the drive capacitor C1. The direct-current vacuum circuit breaker has advantages that the effective magnetic field can be generated without grooving a contact of the arc extinguishing chamber, contact area increasing, arc energy reduction, circuit breaker switching capacity increasing and the like are achieved, andthe direct-current vacuum circuit breaker is applicable to high-current power systems.

Description

technical field [0001] The invention belongs to the technical field of power system fault protection, and in particular relates to a DC vacuum circuit breaker. Background technique [0002] With the advancement of technology, DC power distribution has become the mainstream direction of power system development, and DC circuit breakers, as the core protection equipment of power systems, must become one of the current research hotspots. Compared with the natural zero-crossing point of the current of the AC circuit breaker, the DC circuit breaker itself has no current zero-crossing point, and the artificial zero-crossing point needs to be manufactured through the commutation technology. However, in the medium-voltage and high-current field, the current change rate near the zero-crossing point of the vacuum switch current is usually reduced by increasing the capacity of the commutation capacitor or the inductance of the commutation branch. The volume of the device. [0003] Th...

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Problems solved by technology

[0004] The traditional method of introducing the longitudinal magnetic field to the circuit breaker is to change the current flow path by opening slots on the vacuum switch contacts in the arc extinguishing chamber. This method not only reduces the effective area of ​​the contacts, increases the contact resistance of the contacts, and causes unnecessary loss; and the traditional magnetic field generated by the contact structure, the magnetic field strength is easy to change significantly with the contact opening distance and current during the breaking process, and the magnetic field is not stable enough, thus limiting its ability to break large currents

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