Single-pole ground fault protection method for DC lines based on similarity of current mode components

A single-pole ground fault, DC line technology, applied in emergency protection circuit devices, short-circuit testing, electrical components, etc., can solve problems such as unobvious fault characteristics, high single-pole fault rate of DC distribution network, and increased difficulty of fault identification , to achieve the effect of strong resistance to transition resistance

Active Publication Date: 2022-06-24
ELECTRIC POWER RESEARCH INSTITUTE OF STATE GRID SHANDONG ELECTRIC POWER COMPANY +1
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AI Technical Summary

Problems solved by technology

[0004] The unipolar fault rate of DC distribution network is relatively high, and the fault characteristics are not obvious when grounded through a large resistance
The transition resistance of single-pole grounding faults has a large range of changes, which further increases the difficulty of fault identification

Method used

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Embodiment Construction

[0015] The present invention will be further described below.

[0016] A single-pole grounding fault protection method for DC lines based on similarity of current mode components, comprising the following steps:

[0017] a) When a single-pole ground fault occurs, the electrical quantities of the positive and negative electrodes are not symmetrical, so the phase-mode decoupling matrix is ​​used to obtain the current-mode component x 1 and the zero modulus component x 0 , when the line fails, the fault current-modulus component x 1 with zero modulo component x 0 equal. When an out-of-area fault occurs and normal operation occurs, the sum of a mode current at both ends of the line is a mode current on the ground capacitor. Due to the symmetrical characteristics of the capacitor blocking the DC and DC distribution networks, the current on the ground capacitor is mainly harmonic current and the positive and negative lines are symmetrical. Therefore, the one-mode current of the ...

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Abstract

A DC line unipolar ground fault protection method based on the similarity of the current mode components, based on the similarity between the sum of the zero-mode components and the one-mode components of the current at both ends of the line According to the differences, a protection method for unipolar ground faults of DC lines is proposed, and the data window length can be flexibly selected according to actual needs. The protection method can reliably distinguish unipolar ground faults inside and outside the DC line area, and has a strong ability to resist transition resistance .

Description

technical field [0001] The invention relates, in particular, to a method for protecting a DC line single-pole grounding fault based on the similarity of current mode components. Background technique [0002] In recent years, energy shortage and environmental pollution have promoted the development of distributed power generation. The electric energy generated by common distributed distributed power generation is mostly direct current and unstable alternating current, such as photovoltaic power generation, wind power generation, gas turbine power generation and fuel cells. Compared with connecting to the AC grid, the distributed power generation can save some AC-DC conversion links. At the same time, the demand for direct current electricity consumption of users has increased significantly. Under the above background, the flexible DC power distribution system has received extensive attention. Compared with the AC system, the DC power distribution system has the advantages of...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02H7/26G01R31/52
CPCH02H7/268G01R31/52
Inventor 黄敏张世栋刘洋王峰张林利李文博刘合金苏国强李帅张鹏平由新红
Owner ELECTRIC POWER RESEARCH INSTITUTE OF STATE GRID SHANDONG ELECTRIC POWER COMPANY
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