Power distribution network fault arc extinction method by connecting neutral point to the ground through multi-level converter

Abstract

The invention relates to a power distribution network fault arc extinction method by connecting a neutral point to the ground through multi-level converter. The power distribution network fault arc extinction method is characterized in that the cascade H-bridge multi-level converter is adopted and directly connected at the position of the neutral point of a power distribution network through a reactor; at the initial moment when the power distribution network has a single-phase earth fault, synthetic operation is conducted to generate offset currents needed to be injected (img file='69356dest_path_image001. TIF'wi'19' he'=25' / ), then the offset currents are quickly put into the multi-level converter, the multi-level converter is controlled by aid of the current tracking control algorithm and the PWM (Pulse-Width Modulation) modulation strategy to generate offset currents (img file='652784dest_path_image001. TIF'wi'19' he'=25' / ), and the offset currents are put into the neutral point of the power distribution network so as to compensate grounding total currents of the fault point. In addition, the fault phase voltage is forced to be 0 constantly so the instantaneous grounding fault can be cleared automatically, and further the technical problem of the existing fault arc extinction technology of poor arc extinction effect can be solved.

Description

technical field [0001] The invention relates to the technical field of arc suppression for grounding faults in distribution networks. Background technique [0002] The distribution network has a wide coverage, deep user terminals, complex structure, variable operation mode, frequent random faults, and about 70% of the distribution network faults are instantaneous ground faults. With the continuous extension and expansion of the distribution network, the ground current at the fault point increases, and the arc suppression ability of the instantaneous ground fault is poor. The arc grounding overvoltage amplitude is relatively high, which can reach 2.5~3.5 times of the phase voltage or even higher. The action time is long and the harmful effect is great. Under certain conditions, it will cause multiple faults, cause large-scale power outages, endanger the safety of the power grid, and affect the society. Stablize. [0003] In order to limit the ground fault current, my countr...

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to provide a distribution network fault arc suppression method in which the neutral point is grounded through a multilevel converter, and solve the technical problem of poor arc suppression effect of the existing fault arc suppression technology

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