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MMC-MTDC system coordination starting control method

A pre-charging and sub-module technology, applied in the direction of output power conversion devices, electrical components, etc., can solve problems such as increased start-up time, start-up failure, large electrical shock, etc., and achieve the effect of effective start-up control

Active Publication Date: 2015-08-05
XUJI GRP +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0011] The purpose of the present invention is to provide a coordinated start-up control method for MMC-MTDC systems to solve the above-mentioned problem 2. In the stage of uncontrolled charging, not distinguishing between charging modes is likely to cause a large electrical shock, increase the start-up time or even cause start-up failure The problem

Method used

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  • MMC-MTDC system coordination starting control method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0043] A method for starting a modularized multi-level flexible direct current transmission converter, including the following steps:

[0044] A. The DC side poles of each converter station are connected, the sub-modules of each station are locked, and the AC switch of the active station is closed at the same time, entering the uncontrolled charging stage;

[0045] B. After the sub-module voltage of each converter station is higher than the corresponding charging threshold voltage, the controllable voltage equalization charging method is respectively used to enter the controllable charging stage. At the same time, the active station cuts off the soft-start resistance of the AC side;

[0046] C. When the station control method is constant DC voltage control, after the AC and DC side voltages of the converter station are stable, the station is put into closed-loop voltage equalization charging method; when the sub-module voltage reaches the rated and stable, the station unlocks t...

Embodiment 2

[0087] A method for starting a modularized multi-level flexible direct current transmission converter, including the following steps:

[0088] A. Enter the stage of uncontrolled charging; according to the AC and DC side power supply conditions, put into AC side pre-charging, DC side pre-charging or AC-DC side hybrid pre-charging respectively.

[0089] B. After the sub-module voltage of each converter station is higher than the corresponding charging threshold voltage, the controllable voltage equalization charging method is respectively used to enter the controllable charging stage. At the same time, the active station cuts off the soft-start resistance of the AC side.

[0090] C. When the sub-module voltage of the converter sub-module controlled by the station control mode is constant DC voltage reaches the rated and stable, it first enters the unlocking operation stage; when the sub-module voltage of the other stations reaches the rated and stable voltage, they are respective...

Embodiment 3

[0093] The process of this embodiment is basically the same as that of Embodiment 2. The only difference from Embodiment 2 is that step C is closed-loop charging to unlocking operation, no distinction is made between the DC voltage control station and other converter stations, and the sub-modules of each converter station are unlocked after the voltage is stable. .

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Abstract

The invention relates an MMC-MTDC system coordination starting control method comprising the following steps that A. the DC side poles of all converter stations are connected, the submodules of all the stations are locked, and the AC switch of an active station is closed so as to enter an uncontrollable charging stage; B. after voltage of the submodules of all the converter stations is higher than respectively corresponding charging threshold voltage, a controllable voltage equalizing charging method is switched on by the converter stations respectively and a controllable charging stage is initiated, and the AC side soft starting resistor of the active station is removed simultaneously; and C. the submodules of all the converter stations are charged until unlock operation is performed. According to the uncontrollable charging stage, AC side pre-charging, DC side pre-charging or AC-DC side mixed pre-charging are respectively switched on according to the situation of AC and DC side power supplies. In the uncontrollable charging stage, the charging modes of all converters are clear, and corresponding charging threshold voltage can be obtained according to different modes so that charging mode switching at appropriate time is facilitated for the converters.

Description

technical field [0001] The invention relates to an MMC-MTDC system coordination starting control method. Background technique [0002] Multi-terminal flexible DC transmission can realize multi-source power supply and multi-drop power receiving, which is a flexible, reliable and fast power transmission method in the power system. The modular multilevel converter has gradually become the development trend of multi-terminal flexible DC transmission due to its advantages of high output voltage waveform quality, low switching loss, easy expansion and strong fault ride-through capability. [0003] The successful completion of the start-up process is the premise and basis for the normal operation of the multi-terminal system. A suitable start-up strategy should be able to coordinate and configure the start-up sequence of each converter in the multi-terminal system, suppress the electrical shock caused by their mutual influence, and avoid start-up failure. However, the MMC-MTDC DC ...

Claims

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Application Information

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IPC IPC(8): H02M1/36
CPCH02M1/36
Inventor 杨美娟吴金龙王先为刘欣和张浩李道洋
Owner XUJI GRP