MMC-UPFC-based three-phase imbalance governance system and method of power transmission line

An MMC-UPFC, transmission line technology, applied in the field of MMC-UPFC-based three-phase unbalance management system for transmission lines, can solve problems such as three-phase unbalance, prevent light load and overload, and expand application functions.

Inactive Publication Date: 2017-03-15
SHANDONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] The purpose of the present invention is to solve the above problems, and propose a system and method for three-phase unbalance control of trans

Method used

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  • MMC-UPFC-based three-phase imbalance governance system and method of power transmission line
  • MMC-UPFC-based three-phase imbalance governance system and method of power transmission line
  • MMC-UPFC-based three-phase imbalance governance system and method of power transmission line

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Embodiment 1

[0090] For the voltage balance at both ends of the line, the three-phase unbalance phenomenon caused by the transmission line itself, such as the parameter imbalance of the overhead line, the coupling effect between the parallel lines of the transmission corridor, and the difference between the phases of the cable line. The above factors all lead to the asymmetry of the line parameters, which in turn leads to the imbalance of the three-phase current.

[0091] The MMC-UPFC device is installed at the sending end, and the control method of the three-phase unbalance control of the present invention is applied, and the negative sequence voltage component U is generated in step 2. - sejref Add it to the line to offset the existing negative sequence voltage component in the line, thereby weakening the negative sequence current component. In step 3, select the wiring mode of the transformer, and suppress the zero-sequence current part through the excitation reactance of the series tr...

Embodiment 2

[0093] For the unbalanced three-phase phenomenon on the transmission line caused by the unbalanced voltage at both ends of the line, such as the unbalanced voltage at the receiving end of the transmission line caused by the unbalanced three-phase of the distribution network. The above-mentioned line parameters are three-phase symmetrical, and the three-phase current imbalance problem is caused by the unbalanced voltage at both ends.

[0094] Install an MMC-UPFC device at the sending end, apply the control method of the three-phase unbalance treatment of the present invention, and generate the negative sequence voltage component U in step 2 - sejref Add it to the line to offset the negative sequence voltage component in the power supply at both ends of the line, and then suppress the negative sequence current component generated by the negative sequence voltage in the line. In step 3, by selecting the wiring mode of the transformer, the zero-sequence current flows through the ...

Embodiment 3

[0096] For the three-phase unbalance phenomenon caused by the temporary fault of the AC system on the transmission line, such as the voltage asymmetry at the receiving end of the transmission line caused by single-phase grounding or two-phase short-circuit faults at the remote end of the receiving end system. The above-mentioned line parameters are three-phase symmetrical, and the three-phase current imbalance problem is caused by the remote fault of the receiving end system.

[0097] Install an MMC-UPFC device at the sending end, apply the control method of the three-phase unbalance treatment of the present invention, and generate the negative sequence voltage component U in step 2 - sejref Add it to the line to offset the negative sequence voltage component in the power supply at both ends of the line, and then suppress the negative sequence current component generated in the line by the receiving end fault. In step 3, by selecting the connection mode of the transformer, th...

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Abstract

The invention discloses an MMC-UPFC-based three-phase imbalance governance system and method of a power transmission line. The system comprises a modular multilevel-unified power flow controller MMC-UPFC, wherein the MMC-UPFC comprises a parallel side converter and a series side converter which are in back-to-back connection and share a same DC bus; the parallel side converter is connected with an AC side of a power grid through a parallel transformer; and the series side converter is connected with a power transmission line side through a series transformer. The system and the method disclosed by the invention have the beneficial effects that control on power flow of the power transmission line can be achieved while a three-phase imbalance problem of the power transmission line is solved, the problems of a light load and an overload of the power transmission line can be solved; the application function is expanded; and safe, economic and stable operation of a power system is ensured.

Description

technical field [0001] The invention belongs to the technical field of power system power quality, and in particular relates to a three-phase unbalance control system and method for transmission lines based on MMC-UPFC (modular multilevel-unified power flow controller). Background technique [0002] With the rapid development of the transmission network, the power quality of the transmission line has received more and more attention, and the three-phase unbalance is one of the important indicators of the power quality. Due to the increase of local ring networks in the transmission network, the large-scale application of communication and power electronic equipment, and the diversity of user loads, the three-phase imbalance of the distribution network has caused the three-phase imbalance of the transmission line to become more and more serious. In power system, three-phase unbalance can be divided into fault unbalance and non-fault unbalance. For non-faulty three-phase unbal...

Claims

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Application Information

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IPC IPC(8): H02J3/26H02J3/18
CPCH02J3/1814H02J3/26Y02E40/10Y02E40/50
Inventor 郝全睿满九方王淑颖高厚磊
Owner SHANDONG UNIV
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