快速直流断路器是实现直流电网故障元件快速隔离、构建直流电网的关键设备。该文分析了直流电力系统对快速直流断路器的需求,对空气式直流断路器、直流固态断路器、混合型直流断路器(hybrid DC circuit breaker,HDCCB)的工作原理、优缺...快速直流断路器是实现直流电网故障元件快速隔离、构建直流电网的关键设备。该文分析了直流电力系统对快速直流断路器的需求,对空气式直流断路器、直流固态断路器、混合型直流断路器(hybrid DC circuit breaker,HDCCB)的工作原理、优缺点和研究现状进行综述,最后对快速直流断路器研发中的关键问题进行了展望。展开更多
As a new generation of direct current(DC)transmission technology,voltage sourced converter(VSC)based high voltage direct current(HVDC)has been widely developed and applied all over the world.China has also carried out...As a new generation of direct current(DC)transmission technology,voltage sourced converter(VSC)based high voltage direct current(HVDC)has been widely developed and applied all over the world.China has also carried out a deep technical research and engineering application in this area,and at present,it has been stepped into a fast growing period.This paper gives a general review over China’s VSC based HVDC in terms of engineering technology,application and future development.It comprehensively analyzes the technical difficulties and future development orientation on the aspects of the main configurations of VSC based HVDC system,topological structures of converters,control and protection technologies,flexible DC cables,converter valve tests,etc.It introduces the applicable fields and current status of China’s VSC based HVDC projects,and analyzes the application trends of VSC based HVDC projects both in China and all over the world according to the development characteristics and demands of future power grids.展开更多
This paper investigates a control and protection strategy for a four-terminal modular multilevel converter(MMC)based high-voltage direct current(HVDC)system under a converter-side AC fault.Based on the system operatin...This paper investigates a control and protection strategy for a four-terminal modular multilevel converter(MMC)based high-voltage direct current(HVDC)system under a converter-side AC fault.Based on the system operating condition,a control and protection strategy against the fault with normal blocking of the converter is proposed.In practical,applications encountering such a fault,the MMC at the fault side may experience different conditions of blocking failure.The blocking failures may occur on:①the whole converter;②one converter arm;③one sub-module(SM)/several SMs of one converter arm;④other conditions.The phenomenon of the multi-terminal HVDC(MTDC)system following the fault is analyzed under the first three conditions with real-time simulations using the real-time digital simulator(RTDS).Based on the impact of different conditions on the MTDC system,the necessity of utilizing special control and protection is discussed.A special control and protection strategy is proposed for emergency conditions,and its effectiveness is verified by real-time simulation results.展开更多
Multi-terminal direct current(MTDC)grids provide the possibility of meshed interconnections between regional power systems and various renewable energy resources to boost supply reliability and economy.The modular mul...Multi-terminal direct current(MTDC)grids provide the possibility of meshed interconnections between regional power systems and various renewable energy resources to boost supply reliability and economy.The modular multilevel converter(MMC)has become the basic building block for MTDC and DC grids due to its salient features,i.e.,modularity and scalability.Therefore,the MMC-based MTDC systems should be pervasively embedded into the present power system to improve system performance.However,several technical challenges hamper their practical applications and deployment,including modeling,control,and protection of the MMC-MTDC grids.This paper presents a comprehensive investigation and reference in modeling,control,and protection of the MMC-MTDC grids.A general overview of state-of-the-art modeling techniques of the MMC along with their performance in simulation analysis for MTDC applications is provided.A review of control strategies of the MMC-MTDC grids which provide AC system support is presented.State-of-the art protection techniques of the MMCMTDC systems are also investigated.Finally,the associated research challenges and trends are highlighted.展开更多
空间电荷积聚在电缆附件绝缘界面上会引起局部电场发生畸变,已成为直流电缆附件发展的主要制约因素。为此,提出了一种新的直流电缆附件设计理念,采用与电缆绝缘相似的交联聚乙烯材料模注在电缆绝缘层上制作成应力锥和附件的增强绝缘层,...空间电荷积聚在电缆附件绝缘界面上会引起局部电场发生畸变,已成为直流电缆附件发展的主要制约因素。为此,提出了一种新的直流电缆附件设计理念,采用与电缆绝缘相似的交联聚乙烯材料模注在电缆绝缘层上制作成应力锥和附件的增强绝缘层,使得直流电缆附件的增强绝缘层与电缆绝缘层在交界面处融成一体,一定程度上消除了界面,进而从根本上改善了原界面上空间电荷的积聚情况。依据该设计理念研发的±200 k V直流无界面电力电缆附件已经按照国际大电网会议CIGRE TB 496推荐的试验方法通过型式试验,验证了该设计理念的正确性。展开更多
The renewable energy sources(RESs)dominated power grid is an envisaged infrastructure of the future power system,where the commonly used grid following(GFL)control for grid-tied converters suffers from lacking grid su...The renewable energy sources(RESs)dominated power grid is an envisaged infrastructure of the future power system,where the commonly used grid following(GFL)control for grid-tied converters suffers from lacking grid support capability,low stability,etc.Recently,emerging grid forming(GFM)control methods have been proposed to improve the dynamic performance and stability of grid-tied converters.This paper reviews existing GFM control methods for the grid-tied converters and compares them in terms of control structure,grid support capability,fault current limiting,and stability.Considering the impact of fault current limiting strategies,a comprehensive transient stability analysis is provided.In addition,this paper explores the typical applications of GFM converters,such as AC microgrid and offshore wind farm high-voltage direct current(OWF-HVDC)integration systems.Finally,the challenges to the GFM converters in future applications are discussed.展开更多
文摘快速直流断路器是实现直流电网故障元件快速隔离、构建直流电网的关键设备。该文分析了直流电力系统对快速直流断路器的需求,对空气式直流断路器、直流固态断路器、混合型直流断路器(hybrid DC circuit breaker,HDCCB)的工作原理、优缺点和研究现状进行综述,最后对快速直流断路器研发中的关键问题进行了展望。
基金This work was supported by National Natural Science Foundation of China(No.51261130471).
文摘As a new generation of direct current(DC)transmission technology,voltage sourced converter(VSC)based high voltage direct current(HVDC)has been widely developed and applied all over the world.China has also carried out a deep technical research and engineering application in this area,and at present,it has been stepped into a fast growing period.This paper gives a general review over China’s VSC based HVDC in terms of engineering technology,application and future development.It comprehensively analyzes the technical difficulties and future development orientation on the aspects of the main configurations of VSC based HVDC system,topological structures of converters,control and protection technologies,flexible DC cables,converter valve tests,etc.It introduces the applicable fields and current status of China’s VSC based HVDC projects,and analyzes the application trends of VSC based HVDC projects both in China and all over the world according to the development characteristics and demands of future power grids.
基金This work is supported by UK EPSRC and UK National Grid.
文摘This paper investigates a control and protection strategy for a four-terminal modular multilevel converter(MMC)based high-voltage direct current(HVDC)system under a converter-side AC fault.Based on the system operating condition,a control and protection strategy against the fault with normal blocking of the converter is proposed.In practical,applications encountering such a fault,the MMC at the fault side may experience different conditions of blocking failure.The blocking failures may occur on:①the whole converter;②one converter arm;③one sub-module(SM)/several SMs of one converter arm;④other conditions.The phenomenon of the multi-terminal HVDC(MTDC)system following the fault is analyzed under the first three conditions with real-time simulations using the real-time digital simulator(RTDS).Based on the impact of different conditions on the MTDC system,the necessity of utilizing special control and protection is discussed.A special control and protection strategy is proposed for emergency conditions,and its effectiveness is verified by real-time simulation results.
基金funded by SGCC Science and Technology Program under project Research on Electromagnetic Transient Simulation Technology for Large-scale MMC-HVDC Systems.
文摘Multi-terminal direct current(MTDC)grids provide the possibility of meshed interconnections between regional power systems and various renewable energy resources to boost supply reliability and economy.The modular multilevel converter(MMC)has become the basic building block for MTDC and DC grids due to its salient features,i.e.,modularity and scalability.Therefore,the MMC-based MTDC systems should be pervasively embedded into the present power system to improve system performance.However,several technical challenges hamper their practical applications and deployment,including modeling,control,and protection of the MMC-MTDC grids.This paper presents a comprehensive investigation and reference in modeling,control,and protection of the MMC-MTDC grids.A general overview of state-of-the-art modeling techniques of the MMC along with their performance in simulation analysis for MTDC applications is provided.A review of control strategies of the MMC-MTDC grids which provide AC system support is presented.State-of-the art protection techniques of the MMCMTDC systems are also investigated.Finally,the associated research challenges and trends are highlighted.
文摘空间电荷积聚在电缆附件绝缘界面上会引起局部电场发生畸变,已成为直流电缆附件发展的主要制约因素。为此,提出了一种新的直流电缆附件设计理念,采用与电缆绝缘相似的交联聚乙烯材料模注在电缆绝缘层上制作成应力锥和附件的增强绝缘层,使得直流电缆附件的增强绝缘层与电缆绝缘层在交界面处融成一体,一定程度上消除了界面,进而从根本上改善了原界面上空间电荷的积聚情况。依据该设计理念研发的±200 k V直流无界面电力电缆附件已经按照国际大电网会议CIGRE TB 496推荐的试验方法通过型式试验,验证了该设计理念的正确性。
基金supported by the Xinjiang Autonomous Region Key R&D Projects(No.2020B02002)。
文摘The renewable energy sources(RESs)dominated power grid is an envisaged infrastructure of the future power system,where the commonly used grid following(GFL)control for grid-tied converters suffers from lacking grid support capability,low stability,etc.Recently,emerging grid forming(GFM)control methods have been proposed to improve the dynamic performance and stability of grid-tied converters.This paper reviews existing GFM control methods for the grid-tied converters and compares them in terms of control structure,grid support capability,fault current limiting,and stability.Considering the impact of fault current limiting strategies,a comprehensive transient stability analysis is provided.In addition,this paper explores the typical applications of GFM converters,such as AC microgrid and offshore wind farm high-voltage direct current(OWF-HVDC)integration systems.Finally,the challenges to the GFM converters in future applications are discussed.
