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

TLDR: In this paper, a 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, and the offset currents are quickly put into the multi-layer converter, the multilevel converter is controlled by aid of the current tracking control algorithm and the PWM (Pulse-width modulation) modulation strategy to generate offset currents.

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.