Low-current disjunction device and disjunction method for direct-current distribution system

Abstract

The invention discloses a medium-voltage direct-current (DC) circuit breaker transfer type low-current disjunction device and disjunction method. According to the invention, the low-current disjunction transfer branch circuit is composed of a DC contactor and a controllable silicon thyristor by connection in series. In the process of switching on / off low current, the low-current detection judgment control device emits a signal to trigger the controllable thyristor to be conducted, so that the low current to be subjected to disjunction is transferred to the DC contactor branch circuit. Becausethe current is very low, the current is safely and quickly subjected to disjunction by selecting a proper DC contactor, and finally the process of transferring and disjunction of the low current is finished. The device is simple in structure and reasonable in layout, the equipment work reliability is improved on the premise that the fault low current is guaranteed to be successfully subjected to disjunction, the manufacturing cost is low, and disjunction device and disjunction method are suitable for popularization and application.

Description

technical field [0001] The invention designs a small current breaking device for a medium voltage direct current circuit breaker, in particular to a transfer type small current breaking device for a medium voltage direct current circuit breaker and a breaking method thereof for a direct current power distribution system. Background technique [0002] With the development of DC motors, power semiconductors, electric energy storage, renewable energy power generation, and fuel cell technology, the advantages of DC power supply continue to emerge, and people begin to re-emphasize the prospect of DC power supply. The relationship between DC power supply system and industrial development and people's daily life The connection is also getting closer, and it has been widely used in many important industries such as smelting, chemical industry, medical treatment and mining in our country. Among them, the DC circuit breaker has the protection function of reliably cutting off the fault...

AI Technical Summary

Problems solved by technology

When the breaking current value is large, the magnetic field intensity of the contact and the arc running area is relatively large, and the arc has obvious magnetic blowing and air blowing effects on itself, so the fault current with a large magnitude is easier to break

However, when breaking a small fault current, the effects of magnetic blowing and air blowing are significantly weakened, and the lateral force received by the small current arc is too small, so that the arc cannot quickly enter the grid for cooling and cutting, but stays between the contacts Continuous burning for a long time will cause severe ablation of the moving and static contacts, material loss, and local metal droplets splashing on the contact surface, which will eventually lead to breaking failure

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