Multifunctional arc extinction converter and control method thereof

Abstract

The invention relates to a multifunctional arc-extinguishing converter and a control method thereof, the multifunctional arc-extinguishing converter comprises a three-phase cascaded H-bridge shaping circuit unit, each phase in the cascaded H-bridge shaping circuit unit has the same structure and comprises a plurality of sub-modules, the multifunctional arc-extinguishing converter also comprises a square wave circuit unit connected in series with the cascaded H-bridge shaping circuit unit, and the square wave circuit unit is connected in series with the cascaded H-bridge shaping circuit unit. The square wave circuit unit is a three-phase four-bridge-arm diode clamping type circuit. According to the multifunctional arc-extinguishing converter, when a power distribution network is normal, n phases of an NPC converter in a square wave circuit unit are blocked, the multifunctional arc-extinguishing converter works in a reactive compensation mode, and when the power distribution network has a single-phase earth fault, the multifunctional arc-extinguishing converter works in an arc-extinguishing mode; one phase or two phases of non-fault phases are used for injecting arc extinction current to compensate the ground capacitance current of the power distribution network, so that the current of a fault point is inhibited to be 0. According to the multifunctional arc extinction converter, the cascade number can be effectively reduced, the cost is reduced, the loss is reduced, and the efficiency and the power density are improved.

Description

technical field [0001] The invention relates to the technical field of arc suppression in distribution networks, in particular to a multifunctional arc suppression converter and a control method thereof. Background technique [0002] The structure of the distribution network is complex and changeable, and random faults occur frequently, of which more than 70% of the faults are single-phase grounding faults. And with the continuous increase of the distribution network capacity and the increasing proportion of cable lines, the single-phase ground fault current increases sharply, and the arc is difficult to extinguish by itself. If the arc cannot be extinguished in time, it is easy to cause serious electrical accidents such as insulation breakdown, interphase short circuit and forest fire. [0003] As a typical passive arc suppression device, arc suppression coils are widely used in distribution networks, but they can only compensate for the reactive power component in the gro...

AI Technical Summary

Problems solved by technology

[0006] Aiming at the problems of existing active arc suppression devices, the present invention provides a multifunctional arc suppression converter and its control method that can reduce the number of cascades, improve efficiency and power density, and reduce costs

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