MMC direct current voltage balance control method capable of forming direct current voltage converter station based on cascaded MMC

A technology of DC converter station and DC voltage, applied in the direction of converting AC power input to DC power output, electrical components, power transmission AC network, etc. Control strategies for pressure problems and other issues, to achieve a strong general effect

Active Publication Date: 2018-09-28
CENT SOUTHERN CHINA ELECTRIC POWER DESIGN INST CHINA POWER ENG CONSULTING GROUP CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

In fact, this document only simulates several typical working conditions, and does not consider the problem of unbalanced voltage distribution in the series MMC units of the converter station, nor does it completely eliminate the voltage equalization problem of the series MMC units. control strategy

Method used

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  • MMC direct current voltage balance control method capable of forming direct current voltage converter station based on cascaded MMC
  • MMC direct current voltage balance control method capable of forming direct current voltage converter station based on cascaded MMC
  • MMC direct current voltage balance control method capable of forming direct current voltage converter station based on cascaded MMC

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Embodiment Construction

[0038] In order to describe the present invention more specifically, the technical solutions of the present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0039] The DC transmission system of this embodiment is shown in Figure 2(a), which is a two-terminal unipolar system, and the converter station 1 is an LCC converter station using double 12-pulse converters, as shown in Figure 2(b); Converter station 2 is an MMC converter station. The rated DC voltage of the system is +800kV, and the rated DC power is 2500WM. The rest of the system parameters are shown in Table 1:

[0040] Table 1

[0041]

[0042] It should be pointed out that the rated no-load voltage U of the auxiliary transformer of the converter transformer in the converter station 2 vn0 In this system, it is taken as 0.55 times of the rated DC voltage of the series MMC unit, which can be obtained directly after the rated DC voltage of the series...

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Abstract

The invention discloses an MMC direct current voltage balance control method capable of forming a direct current converter station based on a cascaded MMC. The method comprises the steps of 1, estimating the required number N of MMC units connected in series according to the rated voltage of the system; 2, determining the rated direct current voltage of each MMC unit connected in series; 3, selecting the MMC unit with the minimum rate capacity or the MMC unit with the maximum rate capacity according to the specific value of N; and 4, determining a control strategy used by each MMC unit connected in series. According to the method provided by the invention, the blank of research in current serially connected MMC unit direct current voltage balance strategies is filled, the certain referencecan be provided for future engineering design, the universality is strong, and the method is theoretically applicable to the situation that the rate direct current voltage of each MMC unit connectedin series is the same, and is also applicable to the situation that the rate direct current voltage of each MMC unit connected in series is different from one another.

Description

technical field [0001] The invention belongs to the technical field of electric power transmission and distribution, and in particular relates to an MMC DC voltage balance control method based on MMC cascading to form a DC converter station. Background technique [0002] Compared with the grid commutated converter (Line Commutated Converter, LCC), the modular multilevel converter (ModularMultilevel Converter, MMC) has good harmonic characteristics, no commutation failure problem, and can provide power to weak AC With technical advantages such as system / passive network power supply, several MMC-type high-voltage direct current transmission (MMC-HVDC) projects have been put into operation in recent years, showing great application potential in the field of high-voltage direct current transmission. [0003] The further application of MMC in HVDC transmission system is mainly limited by the level of DC voltage and DC current. In the Zhangbei multi-terminal MMC-HVDC project curr...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02J3/36H02M7/483
CPCH02J3/36H02M7/483Y02E60/60
Inventor 康义陈凌云程改红邵冲潘旭东朱庆春袁力翔林廷卫徐政张哲任徐雨哲
Owner CENT SOUTHERN CHINA ELECTRIC POWER DESIGN INST CHINA POWER ENG CONSULTING GROUP CORP
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