Looking for breakthrough ideas for innovation challenges? Try Patsnap Eureka!

Hybrid ride-through method for direct-current short-circuit fault of MMC-MTDC system

A DC short-circuit and fault technology, applied in AC network circuits, emergency treatment AC circuit layout, emergency protection circuit devices for limiting overcurrent/overvoltage, etc., can solve the problem of rapid restart of converter stations that cannot take into account system safety Insufficiency, slow fault clearing speed, damage to IGBT and other issues, to achieve safe and fast DC fault ride-through, increase restart speed, and reduce impact

Active Publication Date: 2022-05-27
NORTH CHINA ELECTRIC POWER UNIV (BAODING)
View PDF5 Cites 2 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] However, the current research on the non-blocking ride-through strategy is to control the DC output voltage of the converter to zero, so as to block the fault current. Although the non-blocking fault ride-through can be realized, the fault clearing speed is generally slow
Moreover, during the rapid and deep drop of the DC voltage, it is difficult to match the DC voltage established by inputting a negative level with the fault point voltage in real time. Once a large inrush current is generated, there is still a risk of blocking, and in severe cases, it may even damage the IGBT.
[0009] To sum up, the existing fault ride-through strategies for MMC-MTDC systems mainly target single-ended or double-ended systems, and neither the blocking fault ride-through strategy nor the non-blocking fault ride-through strategy can take into account the safety of the system and the restart of the converter station. the rapidity of

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Hybrid ride-through method for direct-current short-circuit fault of MMC-MTDC system
  • Hybrid ride-through method for direct-current short-circuit fault of MMC-MTDC system
  • Hybrid ride-through method for direct-current short-circuit fault of MMC-MTDC system

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0052] The MMC-MTDC system includes multiple converter stations and multiple transmission lines, such as figure 1 Taking the four-terminal ring network shown as an example, the bipolar short-circuit fault of the DC transmission line is the most serious fault type of overcurrent. Therefore, this embodiment analyzes the fault characteristics of the four-terminal ring network after bipolar short-circuiting occurs.

[0053] Assuming that a bipolar short-circuit fault occurs at a certain point of the line connecting MMC1 and MMC4, the sub-module capacitors in each converter station will be discharged to the fault point through the DC line. Each converter station is equivalent to an RLC series circuit, and the calculation method of each equivalent element is:

[0054] (1)

[0055] in, R g , L g , C g ( g =1,2,3,4) are the converter stations respectively g The equivalent resistance, inductance and capacitance of , R 0g , L 0g , C 0g converter station g bridge arm r...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

The invention discloses a hybrid ride-through method for a DC short-circuit fault of an MMC-MTDC system, and relates to the technical field of power supply power systems, and the method comprises the steps: providing a non-locking fault ride-through strategy based on negative DC voltage control, and improving the clearing speed of a fault current through controlling a converter station to output a negative DC voltage; a hybrid ride-through method is provided on the basis, the converter station is not locked under the condition that overcurrent does not occur, the converter station is actively locked when overcurrent occurs on the bridge arm, and the locked converter station is cut off, so that the unlocked converter station continues to operate, direct current fault ride-through is achieved more safely and quickly, and the fault ride-through efficiency is improved. The influence of direct current fault disturbance on the system is reduced to the maximum extent, and the direct current fault disturbance resistance of the multi-terminal direct current power grid can be improved.

Description

technical field [0001] The invention relates to the technical field of power supply systems, in particular to a hybrid ride-through method for direct current short-circuit faults in an MMC-MTDC system. Background technique [0002] Multi-terminal high voltage direct current (MTDC) system based on modular multilevel converter (MMC), referred to as MMC-MTDC system, is used in photovoltaic DC collection, distributed power access, and new energy base power over long distances. Transmission and other fields have broad application prospects. Modular multilevel converter (MMC) is composed of multiple sub-modules (SM) cascaded with the same structure, and has become the preferred converter topology for flexible DC transmission systems. MMC has many advantages, such as power supply to passive network and weak AC system, low harmonic content, easy expansion of modular design, etc., and has been successfully applied to many multi-terminal flexible DC projects. [0003] However, the v...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Applications(China)
IPC IPC(8): H02J3/36H02H9/02H02H9/04H02H7/26
CPCH02J3/36H02J3/001H02H9/02H02H9/04H02H7/268H02J2003/365Y02E60/60
Inventor 王毅魏子文王琛高玉华张振余欣洋
Owner NORTH CHINA ELECTRIC POWER UNIV (BAODING)
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Patsnap Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Patsnap Eureka Blog
Learn More
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic, Popular Technical Reports.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap|About US| Contact US: help@patsnap.com