柔性直流系统联网-孤岛转换控制策略  

Control strategy of transition between grid-connected and island operation of flexible DC system

作　　者：王柯[1] 朱海勇 刘黎 卢宇[1] 董云龙[1] 邹强[1] WANG Ke;ZHU Haiyong;LIU Li;LU Yu;DONG Yunlong;ZOU Qiang(NARI-Relays Electric Co.,Ltd.,Nanjing 211102,China;State Grid Zhoushan Power Supply Company,Zhoushan,Zhejiang 316000,China)

机构地区：[1]南京南瑞继保电气有限公司,南京211102 [2]国网浙江省电力有限公司舟山供电公司,浙江舟山316000

出　　处：《浙江电力》2023年第7期1-8,共8页Zhejiang Electric Power

基　　金：国网浙江省电力有限公司科技项目(5211ZS2000GR)。

摘　　要：柔性直流输电系统接入海岛电网后,需根据交流拓扑改变控制方式,在联网、孤岛转换过程中,存在扰动过大、高频失稳等现象。首先,提出了柔性直流系统联网转孤岛的方法,通过电气量与开关量的结合,提升柔性直流联网转孤岛的快速性与准确性。接着,建立了柔性直流系统的简单高频模型,分析联网转孤岛期间高频失稳的原因,利用联网转孤岛过程中出现的高频分量,提出了联网转孤岛优化逻辑及孤岛开环控制策略,提高系统稳定性。然后,设计了基于阀侧电流负荷预测的孤岛转联网策略,避免孤岛转联网过程中的过流跳闸。最后,利用在线仿真模型,结合实际工程控制保护装置,验证了所提策略的有效性和正确性。The flexible DC transmission system is connected to the island grid,so the control mode needs to be changed according to the AC topology.In the process of grid-connected and island operation conversion,there are phenomena such as excessive disturbance,high frequency instability and so on.Firstly,the transition method from grid-connected operation to island operation is put forward.The speed and accuracy of the transition from gridconnected operation to island operation of flexible DC system can be improved through the combination of electric quantity and switching quantity.Then,a simple high-frequency model of the flexible DC system is established to analyze the causes of high-frequency component during the transition from grid-connected operation to island opera⁃tion.Combined with the high-frequency instability of the transition from grid-connected operation to island opera⁃tion,the optimal logic of the transition from grid-connected operation to island operation and the island open-loop control strategy are proposed to improve the stability of the system.Thirdly,the transition strategy of island opera⁃tion to grid-connected operation is designed based on the load forecasting of valve side current to avoid the overcur⁃rent trip during the process from island operation to grid-connected operation.Finally,the effectiveness and correct⁃ness of the proposed strategy are verified by the online simulation model combining the control protection devices in actual engineering.

关 键 词：柔性直流输电 阻抗 联网 孤岛 高频失稳 临时闭锁 

分 类 号：TM721.1[电气工程—电力系统及自动化]