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MMC-HVDC transient state quantity protection method capable of identifying lightning stroke interference

A MMC-HVDC, transient technology, applied in emergency protection circuit devices, emergency protection detection, parts of emergency protection devices, etc., can solve problems such as refusal to operate, and achieve prevention of malfunction, high resistance to transition resistance, Guarantee the effect of stable and continuous operation

Active Publication Date: 2021-11-05
TIANJIN UNIV +1
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Problems solved by technology

[0006] The purpose of the present invention is to provide a MMC-HVDC transient quantity protection method that can identify lightning strike interference and improve reliability. The present invention considers the frequency variation characteristics of the line and the traveling wave transmission process, and constructs The protection scheme effectively solves the high-impedance grounding rejection problem faced by the current single-ended quantity protection, and has strong anti-noise ability

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  • MMC-HVDC transient state quantity protection method capable of identifying lightning stroke interference
  • MMC-HVDC transient state quantity protection method capable of identifying lightning stroke interference
  • MMC-HVDC transient state quantity protection method capable of identifying lightning stroke interference

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Embodiment Construction

[0029] The invention designs a high-frequency protection scheme by utilizing the Hilbert-Huang transformation, and proposes a lightning strike interference identification method by utilizing the characteristics of the lightning wave waveform. Afterwards, the lightning strike criterion is combined with the protection criterion to make up for the deficiency of transient protection and improve its reliability.

[0030] Step (1) Set the protection measurement point at the beginning of the line (the line side of the line reactor), and use the voltage variation of the protection measurement point to realize protection start-up and fault pole selection. Let ΔU be the real-time measured voltage change at the protection installation, ΔU z In order to protect the start-up threshold, it can take 10-25kV according to the voltage fluctuation during normal operation. When the ΔU of two consecutive sampling points satisfies the following formula, the protection starts, t s is the current s...

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Abstract

The invention relates to an MMC-HVDC transient state quantity protection method capable of identifying lightning stroke interference. The method comprises the following steps: (1), arranging a protection measurement point at the initial end of a line, i.e., the line side of a line reactor, and achieving the protection starting and fault pole selection through the voltage variation of the protection measurement point; (2) formulating an internal and external fault identification method by using the high-frequency attenuation effect of the smoothing reactor on the fault traveling wave; and (3), performing fault identification by using the time domain waveform area characteristics, and constructing lightning interference identification criteria by using reverse traveling waves.

Description

technical field [0001] The invention relates to the fields of relay protection and automation of power systems, in particular to a high-frequency transient protection method capable of identifying lightning interference. Background technique [0002] Facing the unsolvable problems in traditional DC transmission, the voltage source converter-based flexible DC transmission technology (VSC-HVDC) has ushered in extensive research and rapid development. The flexible DC transmission technology using two-level or three-level converters cannot meet the current needs of large-capacity and long-distance power transmission. The development prospects have been raised to a higher level. [0003] In order to ensure quick action, the current protection research basically focuses on the transient electrical quantity, and the research angles are mainly divided into two aspects: time domain and frequency domain. The protection method in the time domain has a limited ability to withstand tra...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02H7/26H02H1/00G01R31/08H02J3/36
CPCH02H7/265H02H7/268H02H1/0007G01R31/086H02J3/36Y02E60/60
Inventor 薛士敏陈硕陈萧姚程袁中琛
Owner TIANJIN UNIV
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