Energy-feeding flexible grounding device for power distribution network, fault arc extinction method and direct-current-side-voltage control method and system of energy-feeding flexible grounding device

Abstract

The invention discloses an energy-feeding flexible grounding device for a power distribution network, a fault arc extinction method and a direct-current-side-voltage control method and system of the energy-feeding flexible grounding device. The fault arc extinction method includes the steps that when a single-phase grounding fault is generated, a neutral point of the power distribution network is grounded through a flexible grounding device, the flexible grounding device is controlled to inject a resistive current and a reactive current into the neutral point in sequence, a fault feeder line is judged, and arc extinction of a fault point is promoted. The direct-current-side-voltage control method includes the step that energy exchanging between the flexible grounding device and the power distribution network is achieved through a direct-current-side capacitor voltage outer loop and a three-phase input current inner loop, and therefore it is guaranteed that the direct-current-side voltage is constant. By means of the direct-current-side-voltage control method, the problems that the direct-current-side voltage of a traditional flexible grounding device is difficult to stabilize, the harmonic content of an injected current is high, and system stability is poor can be solved; by switching control modes, the fault feeder line can be accurately identified, an instant grounding fault electric arc can be eliminated, and the power supply reliability of the power distribution network can be improved.

Description

technical field [0001] The invention belongs to the application field of distribution network grounding fault processing, and in particular relates to an energy-feedback flexible grounding device for a distribution network, a fault arc suppression method, and a DC side voltage control method and system thereof. Background technique [0002] The distribution network is at the terminal of the power system, has a complex and changeable structure, and is closely connected with users, which easily leads to various faults. Single-phase ground fault is the most common fault in the distribution network. When the fault current is too large, arc light will be generated, and the arc combustion will cause great harm such as fire and equipment damage. In order to limit the ground fault current, the distribution network in my country generally adopts medium Non-grounded neutral point, grounded through arc suppressing coil, grounded through resistance, etc. With the continuous change of th...

AI Technical Summary

Problems solved by technology

[0004] The present invention provides an energy-feedback flexible grounding device, a fault arc suppression method, and a DC side voltage control method and system for distribution networks. The purpose is to overcome the defects of different grounding methods in the prior art and the traditional flexible The voltage on the DC side of the grounding device is difficult to maintain stability, the harmonic content of the current injected into the flexible grounding device is high, and the system stability is poor

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