A large-capacity AC circuit breaker and control method based on capacitor commutation

Abstract

The invention is applicable to the field of power devices and provides a large-capacity AC circuit breaker and a control method based on capacitor commutation. The circuit breaker includes a plurality of mutually independent single-phase circuit breakers, and each of the single-phase circuit breakers in series In one phase line, it is used to break the current of the corresponding phase line; a topological structure is provided between the input end and the output end of the single-phase circuit breaker; the topological structure includes a flow device, a commutation device and a breaking device. device, the converter device and the breaking device are connected in series, and after being connected in series, the whole body is connected in parallel to both ends of the flow device. The single-phase circuit breaker can provide zero-voltage medium recovery time for gas mechanical switches, has the advantages of fast and reliable breaking, low cost, long life, and can break high DC component short-circuit current. It is used in generator outlet circuit breakers or It has broad application prospects in situations where frequent circuit breaker operations are required.

Description

Technical field [0001] The invention belongs to the field of power devices, and in particular relates to a large-capacity AC circuit breaker and a control method based on capacitive commutation. Background technique [0002] As the capacity of the AC power grid increases, higher requirements are placed on the rated current and short-circuit breaking current of AC circuit breakers. In scenarios with large rated currents, vacuum switches are difficult to apply due to insufficient heat dissipation capabilities, while gas switches have limited arc extinguishing capabilities and face the risk of heavy breakdown in scenarios with high transient recovery voltage (TRV) rise rates. The ablation is severe when breaking a large short-circuit current, and the electrical life is not long. Currently, AC circuit breakers have the problem of high prices of imported equipment and short lifespan of domestic substitute equipment. [0003] Chinese patent "Bidirectional mechanical DC circuit b...

AI Technical Summary

Problems solved by technology

However, this circuit breaker is mainly for DC breaking, and its design makes the breaking overvoltage greater than the DC bus voltage

The topology of this circuit breaker breaks AC with zero-crossing or near-zero fault current, and the cost of capacitors and power electronic switches required for the commutation drive circuit will be very high and unnecessary

In addition, when the mechanical DC circuit breaker breaks a small current, the problem of mechanical switch re-breakdown may occur, resulting in failure. The topology of will be difficult to apply

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