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Ground protection method of modular multilevel converter and modular multilevel converter

A modular multi-level, grounding protection technology, applied to emergency protection circuit devices, AC power input conversion to DC power output, electrical components, etc., can solve the problem of inability to immediately reduce the DC terminal transmission voltage, device damage, and capacitor voltage rise And other issues

Inactive Publication Date: 2016-08-24
ELECTRIC POWER RESEARCH INSTITUTE, CHINA SOUTHERN POWER GRID CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Due to the long power transmission distance, the transmission voltage of the DC terminal cannot be immediately reduced at this time, so that the capacitor in the sub-module between the DC terminal and the ground fault point is overcharged, resulting in a large increase in the capacitor voltage, which in turn causes other devices in the sub-module damaged by overvoltage

Method used

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  • Ground protection method of modular multilevel converter and modular multilevel converter
  • Ground protection method of modular multilevel converter and modular multilevel converter
  • Ground protection method of modular multilevel converter and modular multilevel converter

Examples

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Embodiment 1

[0023] An embodiment of the present invention provides a grounding protection method for a modular multilevel converter. Before describing the grounding protection method, first briefly introduce the structure of a modular multilevel converter. See Figure 1 ~ Figure 3 , the modular multilevel converter 10 includes three phase units 20, each phase unit 20 includes several identical sub-modules 30 connected in series, in this embodiment, combined Figure 4 and Figure 5 In order to prevent the ground fault of the modular multilevel converter 10 from damaging related devices, at least one protection circuit 40 is connected in parallel to each submodule 30 of at least one of the phase units 20. When the modular multilevel converter When a ground fault occurs in the converter 10, control the corresponding protection circuit 40 on each sub-module 30 to conduct, and when the modular multilevel converter 10 is in a normal state, control the corresponding protection circuit 40 on each...

Embodiment 2

[0044] see Figure 2 to Figure 5 , this embodiment provides a modular multilevel converter 10, including three phase units 20, each phase unit 20 includes several identical sub-modules 30 connected in series, each sub-module 30 of at least one phase unit 20 There is at least one protection circuit 40 connected in parallel correspondingly on the top, one end of the protection circuit 40 is connected to the positive pole of the sub-module 30, and the other end of the protection circuit 40 is connected to the negative pole of the sub-module 30, wherein the positive pole of the sub-module 30 is close to the modular multiple The high potential end of the level converter 10 , the negative pole of the sub-module 30 is close to the low potential end of the modular multilevel converter 10 . The protection circuit 40 can be in a conductive state when the modular multilevel converter 10 has a ground fault, and can be in a disconnected state when the modular multilevel converter 10 is in ...

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Abstract

The invention provides a ground protection method of a modular multilevel converter and the modular multilevel converter, and relates to the technical field of direct current power transmission. The ground protection method is used for protecting the modular multilevel converter when a ground fault occurs in the modular multilevel converter. According to the ground protection method of the modular multilevel converter, at least one protection circuit is correspondingly connected in parallel to each submodule of at least one phase unit in the modular multilevel converter, one end of the protection circuit is connected with a positive electrode of the submodule, and the other end of the protection circuit is connected with the a negative electrode of the submodule; when the ground fault occurs in the modular multilevel converter, the protection circuit is controlled to be conducted; and when the modular multilevel converter is in a normal state, the protection circuit is controlled to be disconnected. The ground protection method of the modular multilevel converter, provided by the invention, is used for protecting the modular multilevel converter.

Description

technical field [0001] The invention relates to the technical field of direct current transmission, in particular to a grounding protection method for a modular multilevel converter and the modular multilevel converter. Background technique [0002] A Modular Multilevel Converter (MMC for short) is widely used in a direct current transmission system to output an alternating voltage during power transmission. [0003] The general topology of the modular multilevel converter includes: three phase units, each phase unit is composed of multiple identical sub-modules in series, and each sub-module includes devices such as diodes, thyristors and capacitors. The modular multi-level converter adopts a modular topology. By adjusting the number of sub-modules in series, the voltage and power level can be flexibly changed, and it can be extended to any level of output, thereby reducing electromagnetic interference and output voltage. The harmonic content is very low, the output voltag...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02H7/122H02M7/483
CPCH02H7/122H02M7/483H02M7/4835
Inventor 黄伟煌饶宏黄莹李明李岩
Owner ELECTRIC POWER RESEARCH INSTITUTE, CHINA SOUTHERN POWER GRID CO LTD