摘要
混合级联直流输电系统在向负荷中心送电方面具有优势,但由于其低压端换流器由多个VSC并联构成,在故障穿越及运行方式转换过程中,VSC区域的暂态电流峰值大、衰减时间长,给设备研制与系统性能提升带来巨大挑战。为降低暂态电流,从优化VSC区域主回路入手,提出在VSC直流侧串联二极管,或在旁路开关串联电阻的方案。在此基础上,进一步研究了二极管的布置方案及串联电阻值的选取方法。理论分析与仿真结果表明,2种方案均可有效降低暂态电流的峰值与衰减时间,极大提升换流阀、机械开关及转换开关、测量装置的安全裕度。最后对比了这2种暂态电流抑制方法,并结合工程实际需求给出了推荐方案。
The hybrid cascaded HVDC transmission system is a novel topology that provides advantages in power transmission to a load center.However,its low-end inverter consists of multiple VSCs connected in parallel.Thus,during AC fault ride through and operation mode conversion,the large transient current peak and long decay time in the VSC region pose major challenges for equipment development and system performance improvement.This study optimizes the VSC main circuit and proposes a series diode on the VSC DC side or a series resistor in the bypass switch to reduce the transient current of the novel topology.Based on the two methods,the layout of the diode and the design value of the series resistance are further studied.The peak value and decay time of transient current are effectively reduced.In addition,the safety margins of the valves,mechanical switch,transfer switch,and measurement device are significantly improved.Finally,the study compares the above two transient current suppression methods and recommends a scheme with the consideration of engineering practice.
作者
许冬
李探
梅念
乐波
XU Dong;LI Tan;MEI Nian;YUE Bo(State Grid Economic and Technoligical Research Institute Co.,Ltd.,Changping District,Beijing 102209,China)
出处
《全球能源互联网》
2020年第2期166-171,共6页
Journal of Global Energy Interconnection
基金
国家电网公司科技项目(5202011600TV)
国家重点研发计划项目(2016YFB0900905).
作者简介
通信作者:许冬(1990),男,博士,工程师,研究方向为高压直流输电、电力系统建模。E-mai l:xudong_ncepu@163.com;李探(1989),男,博士,高级工程师,研究方向为直流输电的设计和研究;梅念(1982),女,博士,教授级高级工程师,研究方向为柔性直流输电,E-mail:meinn@126.com;乐波(1976),男,博士,教授级高级工程师,研究方向为特高压直流输电和柔性直流输电技术。
