Medium-pressure and high-capacity DC circuit breaker contact terminal system for improving short time endurance capability

Abstract

The invention discloses a medium-pressure and high-capacity DC circuit breaker contact terminal system for improving short time endurance capability. According to the invention, an arcing contact is added in the circuit breaker to reduce the Holm force between the contact terminals, the flow direction of current in a conducting circuit of the DC circuit breaker is changed by soft connection to generate opposite flow directions of the current between a movable contact terminal and a conductive block of lower bus bar so as to generate electric repulsive force, the repulsive force is converted into pressure between the contacts by means of the rotation property of the movable contact terminal, and a suction force of a magnet material on the movable contact terminal is converted into pressure on the contacts through a rotating shaft to further compensate the electric repulsive force. The medium-pressure and high-capacity DC circuit breaker contact terminal system disclosed by the invention has the advantages that the structure is simple, the layout is reasonable, the electric repulsive force at the contacts is compensated through the electric repulsive force effect generated by the contact terminal system under the condition of not changing the operating mechanism, the movable contact terminal is prevented from being repelled while guaranteeing large short circuit current, and the short time endurance capability of the DC circuit breaker is improved.

Description

technical field [0001] The design of the invention relates to electrical equipment for power supply, distribution and protection of a medium-voltage large-capacity DC system, in particular to an air medium-voltage large-capacity DC circuit breaker with strong short-term withstand capability and selective protection function. Background technique [0002] The DC power supply and distribution system has the advantages of low line cost, large capacity, small active power loss, rapid adjustment, and reliable operation. It has been widely used in urban rail transit and ships in recent years. As a necessary equipment for the safe operation of the DC system, the circuit breaker in the DC system must have the ability to reliably connect, break and carry current under normal circuit operation conditions, and the ability to connect and carry current under specified abnormal circuits (such as short circuits). A certain time and the ability to break the current. Especially for the circ...

AI Technical Summary

Problems solved by technology

Since this kind of circuit breaker has only one contact point, it cannot achieve good contact with the entire contact point. The shrinkage of the current line is relatively serious, and the generated Holm force is relatively large. The electric repulsion force generated on the contact is very huge, it is easy to push the moving contact away

To ensure that the moving contacts will not be repelled in the event of a short-circuit fault, it is often necessary to provide a large closing force. To provide a greater closing force, it will inevitably put forward more stringent requirements for the operating mechanism and increase the manufacturing capacity of the circuit breaker. , operating and maintenance costs

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