A Method for Evaluating the Impact of DC Grid Topology on Fault Current

A technology of fault current and DC power grid, applied in the protection of fault current, electrical components, circuit devices, etc., can solve the problem of fault current without in-depth discussion of topology structure and topology parameters, unsuitable topology research, and failure to propose faults Issues such as indicators of current influence
CN113595044BActive Publication Date: 2022-03-22SICHUAN UNIV
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
SICHUAN UNIV
Publication Date
2022-03-22

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Abstract

The invention discloses a method for evaluating the impact of the topology of a DC power grid on fault currents. First, the equivalent circuit of the grounding mode of the metal return line and the earth return line is established, and a three-dimensional mesh circuit diagram decoupling method is proposed, so that the equivalent circuit plane An improved high-frequency equivalent model was proposed, and fault current calculation methods were deduced for radial and ring networks, and the theory was extended to n terminal network, and then analyzed the influence of topology parameters and structure on fault current; proposed the evaluation index of topology influence on fault current k , which can effectively evaluate the impact of the initial fault current level on the grid topology; k The magnitude of the value determines which converter stations the DC grid unipolar short-circuit fault current mainly comes from at the initial stage. The evaluation method proposed by the invention avoids cumbersome calculations, and can directly and quickly evaluate the influence of the topology on the fault current.
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Description

technical field

[0001] The invention relates to the technical field of DC grid topology and fault current evaluation, in particular to a method for evaluating the influence of DC grid topology on fault current. Background technique

[0002] Multi-terminal flexible DC grid has become a research hotspot due to its advantages of low harmonics, high reliability, and easy expansion. In actual engineering, single-pole ground fault events occur most frequently. After a unipolar ground fault occurs in a true bipolar system, the sub-module discharges rapidly and injects a large amount of surge current into the fault point. The outlet voltage of the converter station drops rapidly, and the bridge arm current and line current rise sharply, seriously threatening the safe and stable operation of the power grid. . Therefore, it is of great significance to study the influence mechanism of topology on unipolar fault current and the influence of topology parameters on fault current for pow...

Claims

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