Accurate Distinction of Weak and Strong AC Grids for Emerging Hierarchical-Infeed LCC-UHVDC Systems  

作　　者：Hao Xiao Xianzhong Duan Yi Zhang 

机构地区：[1]Department of Electrical and Computer Engineering,University of Manitoba,Winnipeg R3T 2N2,Manitoba,Canada [2]State Key Laboratory of Advanced Electromagnetic Engineering and Technology,Hubei Electric Power Security and High Efficiency Key Laboratory,School of Electrical and Electronic Engineering,Huazhong University of Science and Technology,Wuhan 430074,Hubei,China [3]RTDS Technologies Inc.,Winnipeg R3T 2E1,Manitoba,Canada

出　　处：《CSEE Journal of Power and Energy Systems》2024年第2期772-777,共6页中国电机工程学会电力与能源系统学报（英文）

基　　金：supported in part by the National Natural Science Foundation of China(51907067);in part by the Industrial Research Chair Program of the Natural Sciences and Engineering Research Councilof Canada。

摘　　要：Distinction of weak and strong AC grids for emerging hierarchical-infeed LCC-UHVDC systems is important for planning and operation departments. However, accuracy of earlier distinction methods is limited as they were developed by empirical reasoning without rigorous theoretical analysis. Hence in this letter, hierarchical-infeed interactive effective short-circuit ratio (HIESCR) index is first used for strength evaluation of HIDC systems with complex inter-inverter interactions considered. Boundary HIESCR (BHIESCR) is also introduced in the proposed distinction method of weak and strong AC grids. That is, weak (or strong) AC grids are, respectively, identified when HIESCR is less (or greater) than BHIESCR. Second, it is shown BHIESCR remains almost unchanged as 3.0 versus various system parameters and rated operation variables based on rigorous theoretical analysis. This salient feature makes the proposed method more accurate than earlier methods. Finally, the proposed method is validated by simulations based on the PSCAD/EMTDC program.

关 键 词：Hierarchical-Infeedinteractive effective short-circuit ratio hierarchical-infeed LCC-UHVDC systems inter-inverter interactions strong AC grids weak AC grids 

分 类 号：TM91[电气工程—电力电子与电力传动]