标题：Fault Current Analysis of Type-3 WTs Considering Sequential Switching of Internal Control and Protection Circuits in Multi Time Scales During LVRT

作者：Chang,Yuanshu ;Hu,Jiabing; Tangwang,Qianyun; Song, Guobing

摘要：As Type-3 wind turbine (WT) has already become a typical type of highly penetrated power sources in modern power systems, characterizing its properties during grid fault is a basic requirementforsystemanalysis.However,manysignificantfactors have not been considered in the existing analytical methods and results,suchasvariousswitchingofinternalcontrolandprotection circuits in low voltage ride through (LVRT) solutions. In this paper, performance of Type-3 WT during LVRT is first illustrated andsummarizedasthesequentialswitchingcharacteristicinmulti time scales, viz., instant control, ac control, dc voltage control, and rotor speed control time scales. Thus, for magnitude drops in stator voltage, a mathematical model is proposed to understand this characteristic and fault current analysis’s features. Then, an analytical method, based on the operational inductance, is proposed so that fault current components, with the sequential switching considered, can be depicted with a unified and simple analytical expression. By identifying magnitude of symmetrical current, the transient and steady-state equivalent circuits of Type-3 WT are proposed to estimate momentary current and electrical power approximately. Finally, analytical results are verified by comparisons with real-time simulation results of a detailed 1.5 MW WT model in RT-LAB.

发表于：IEEE TRANSACTIONS ON POWER SYSTEMS

发表时间：NOV, 2018