A control method of a mechanical direct current circuit breaker

Abstract

The invention discloses a mechanical direct current circuit breaker and a control method thereof, comprising a main branch, a transfer branch and an energy consumption branch, the three of which are connected in parallel and then connected in series with a current sensor; the transfer branch includes a first transfer connected in parallel The inductance, the second transfer inductance, the third transfer inductance, and the first transfer capacitor, the second transfer capacitor, and the third transfer capacitor connected in parallel, the first trigger device in series on the branch where the second transfer inductance is located, and the branch where the third transfer inductance is located The second trigger device is connected in series on the road, the third trigger device is connected in series on the branch road where the first transfer capacitor is located, the fourth trigger device is connected in series on the branch road where the second transfer capacitor is located, and the fifth trigger device is connected in series on the branch road where the third transfer capacitor is located. In the present invention, the control system selectively triggers the trigger device according to the magnitude of the current, effectively preventing the DC circuit breaker from injecting too much energy into the DC system during the breaking process, and reducing the impact on the system during the breaking process of the DC circuit breaker.

Description

technical field [0001] The invention relates to power system technology, in particular to a mechanical DC circuit breaker and a control method thereof. Background technique [0002] The DC power grid can effectively solve the problems of tight urban power supply corridors, difficulty in absorbing new energy, large load capacity, and high demand for power supply quality with industrial upgrading. However, because the short-circuit current of the DC power grid rises rapidly, has a high peak value, and there is no natural zero-crossing point, the design of DC circuit breakers is more difficult than traditional AC circuit breakers. Under normal working conditions, the DC circuit breaker needs to connect, carry, and break the rated current of the system; when a short-circuit fault occurs, it can quickly cut off the faulty branch, absorb the energy stored in the inductance of the faulty branch, and suppress the system overvoltage. [0003] Commonly used medium voltage DC circuit ...

AI Technical Summary

Problems solved by technology

Since the mechanical circuit breaker needs to have the ability to break the fault current and the normal current of the system at the same time, its transfer branch capacitor C needs to be precharged with a relatively high voltage. When breaking a small current, it will inject a large amount of energy into the system and affect the system. The normal operation of other equipment may even impact the DC transformer or converter valve, causing it to lock up

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