Unidirectional transformation-type high-voltage DC circuit breaker based on Buck convertor

Abstract

The invention discloses a unidirectional transformation-type high-voltage DC circuit breaker based on a Buck convertor. The unidirectional transformation-type high-voltage DC circuit breaker comprises a circuit breaker and a control system. The control system comprises an inner loop adjusting and controlling current and an outer loop adjusting and controlling voltage, and voltage transformation and protection control of the high-voltage DC circuit breaker can be carried out by adding an auxiliary controller in double closed-loop adjustment. The transformation-type high-voltage DC circuit breaker has the advantages of more functions, fast opening and closing speed, and saving cost and the like, compared with a conventional high-voltage circuit breaker. Buck function of the circuit breaker can be realized when a high-voltage DC power transmission system operates normally, and the high-voltage DC circuit breaker can be applied to electric power lines with different voltage classes flexibly; and meanwhile, effective cutting of short circuit fault can be realized quickly when the electric transmission line has short circuit fault, thereby realizing the purpose of protecting high-voltage DC power transmission equipment and load equipment.

Description

technical field [0001] The invention relates to a high-voltage direct current transformation and protection system, in particular to a one-way transformation type high-voltage direct current circuit breaker based on a Buck converter. Background technique [0002] In the high-voltage AC transmission system, the normal input and accidental disconnection of the transmission line are realized through the high-voltage AC circuit breaker. In the high-voltage direct current transmission system, the control of the converter valve control (gate) is used to eliminate temporary faults or when a short-circuit fault occurs, a mechanical high-voltage circuit breaker is used to cut it off. However, with the development of VSC-HVDC power transmission technology Due to the long response time of mechanical high-voltage DC circuit breakers, it is difficult to meet the needs of rapid removal of short-circuit faults. Therefore, it is very necessary to develop a new fast HVDC circuit breaker to ...

AI Technical Summary

Problems solved by technology

[0003] The current mechanical high-voltage DC circuit breaker can cut off the short-circuit current within tens of milliseconds, and the cutting speed of this fault current cannot meet the requirements of the new VSC-HVDC power transmission system

Solid state circuit breakers can easily overcome the limitation of breaking speed, but they will generate a lot of losses in steady state operation

The hybrid circuit breaker combines the good static characteristics of mechanical circuit breakers and the dynamic characteristics of solid state circuit breakers without arc breaking, and has the advantages of low operating loss, long service life, high reliability and good stability, but for the manufacture of fast switch The requirements are very high, and the breaking time is still affected by the fast switch and the protection system and communication time

Images