An AC short circuit fault current limiter

Abstract

The invention relates to an AC short-circuit fault current limiter, comprising: a fast switch, a split reactor, a reactor and a capacitor. Wherein, the split reactor includes a first winding and a second winding whose magnetic flux is reversed. A series resonant circuit composed of a reactor and a capacitor resonates at the power frequency. When the grid is stable, the currents of the branches where the first winding and the second winding are located are equal, the magnetic fluxes cancel, and the current limiter exhibits small impedance or no impedance. After the fault occurs, the short-circuit current contains multiple harmonic components, and the series resonant circuit composed of reactors and capacitors presents impedance, resulting in unequal currents in the branches where the first winding and the second winding are located, increasing the current limiting impedance of the split reactor. , to achieve fast automatic current limiting. Then, the fast switch breaks and extinguishes the arc, which further limits the short-circuit current of the current limiter. The current limiter of the present invention can effectively limit the short-circuit current of the AC power grid and improve the operation reliability of the power grid.

Description

technical field [0001] The invention relates to the field of short-circuit fault current limiters of power transmission and distribution networks, in particular to an AC short-circuit fault current limiter. Background technique [0002] With the increasing demand for electricity in the society, the continuous development of the power system has been driven. Short-circuit current levels continue to increase, and short-circuit faults are increasingly destructive to power systems and their connected electrical equipment. Moreover, while the demand for electric power is increasing day by day, people also put forward higher requirements for power quality, power supply reliability and safety. However, the transient stability problems of large power grids are more prominent, and one of the most important reasons is the lack of effective short-circuit current limiting technology in conventional power technology. At present, circuit breakers are widely used in the world to break sh...

AI Technical Summary

Problems solved by technology

Still, the current-limiting reactor can only be put into operation after the first zero-crossing point after the fault, and the first peak of the short-circuit current cannot be limited.

The first peak impact current of the short-circuit current is large, which will have a great impact on the transformer and other power grid equipment, causing deformation or even damage of the transformer

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