Bidirectional mechanical direct-current circuit breaker based on commutation driving circuit and control method of bidirectional mechanical direct-current circuit breaker

Abstract

The invention provides a bidirectional mechanical direct-current circuit breaker based on a commutation driving circuit and a control method of the bidirectional mechanical direct-current circuit breaker. The bidirectional mechanical direct-current circuit breaker comprises a current passage branch circuit, a commutation branch circuit and an energy-absorbing and voltage-limiting branch circuit, wherein the current passage branch circuit comprises one or a plurality of mechanical switches serially connected with one another; the commutation branch circuit consists of a high-voltage capacitor and a commutation driving circuit which are connected serially; the energy-absorbing and voltage-limiting branch circuit consists of a lightning arrester; and the current passage branch circuit, the commutation branch circuit and the energy-absorbing and voltage-limiting branch circuit are connected with one another in parallel. When bidirectional current requires to be switched on or switched off, current can be transferred to the commutation branch circuit at first from the current passage branch circuit, and then is transferred to the energy-absorbing and voltage-limiting branch circuit, and finally, switch-on and switch-off of the bidirectional current are realized. The bidirectional mechanical direct-current circuit breaker based on the commutation driving circuit has the advantages of low cost, simple structure and high reliability.

Description

technical field [0001] The invention relates to the technical field of power equipment, in particular to a bidirectional mechanical DC circuit breaker based on a commutation drive circuit and a control method thereof. Background technique [0002] The rapid development of multi-terminal DC transmission systems based on voltage source converter stations urgently requires DC circuit breakers to quickly isolate faulty lines on the DC side to ensure reliable power supply from each converter station to normal lines. At present, there are mainly two realization methods of DC circuit breakers: mechanical DC circuit breaker and hybrid DC circuit breaker. Among them, the mechanical DC circuit breaker has attracted attention due to its advantages of low cost and small size. [0003] Currently, current transfer in mechanical DC circuit breakers is achieved by pre-charging capacitors and high-voltage air ball gaps. figure 1 A schematic structural diagram of an existing mechanical DC c...

AI Technical Summary

Problems solved by technology

In this solution, the voltage at both ends of the high-voltage capacitor is 1.5 to 1.6 times the system voltage, and it can only be powered through the DC bus through complex switching operations. When a fault occurs, the voltage of the DC bus drops, and the voltage at both ends of the capacitor is difficult to maintain. The working state of the circuit breaker is unstable

The high-voltage air ball gap in the commutation branch has weak arc-extinguishing ability, but its arc-extinguishing ability is affected by many factors such as contact ablation, contact structure, transient recovery voltage, etc., and the arc-extinguishing time is uncertain , and in air arcing, the reliability is poor

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