Superconductive current limiting based no-arc DC breaker and breaking method thereof

Abstract

The invention relates to a superconductive current limiting based no-arc DC breaker and a breaking method thereof. The breaker comprises a disconnecting switch unit, a superconductive current limiting unit and a no-arc breaking unit in serial connection; the superconductive current limiting unit includes a resistive type superconductive current limiter, and the no-arc breaking unit comprises a mechanical switch, a current converting capacitor and an energy absorbing branch; when a fault occurs, the superconductive current limiting unit quenches superconductivity to limit a short-circuit current, and a rising voltage at the two ends serves as a control signal for motion of the mechanical switch of the no-arc breaking unit; after that the no-arc breaking unit receives the control signal, the DC is disconnected; and finally, the disconnecting switch unit is disconnected in zero current. According to the invention, the superconductive current limiting unit limits the short-circuit current, the charging speed of a current converting capacitor is reduced, and due to that the voltage of the mechanical switch equals that of the current converting capacitor, the voltage of the mechanical switch is lower than a voltage to maintain an arc in certain stage of the disconnecting process, and the arc cannot be generated and is quenched rapidly; and at the same time, the superconductive current limiting unit inhibits voltage and current oscillation in the capacitor, and prevents generation of overvoltage.

Description

technical field [0001] The invention relates to a power system circuit breaker, in particular to an arc-free DC circuit breaker based on superconducting current limiting and a breaking method. Background technique [0002] DC power grid is widely used in ships, railways and new energy due to its low operating loss and convenient load control. However, since the DC current has no natural zero-crossing point, it is relatively difficult for the mechanical switch to complete the breaking by extinguishing the arc. At present, the two ends of the common oscillating mechanical circuit breaker are connected in parallel with an oscillating circuit composed of capacitors and inductors. When breaking, the oscillating circuit generates a zero-crossing point in the arc of the mechanical circuit breaker. Oscillating mechanical circuit breakers include self-excited oscillating circuit breakers and other-excited oscillating circuit breakers. The self-excited oscillation switch has a long ...

AI Technical Summary

Problems solved by technology

At present, the most common arc-free breaking method is hybrid breaking. In order to withstand high voltage and high current, multiple IGBTs need to be connected in series, which not only increases the cost, but also complicates the implementation of IGBT breaking synchronization.

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