Calculation Method for Commutation Failure Fault Level in LCC-HVDC System Under Single-line-to-ground Faults Considering DC Current Variation  

作　　者：Renlong Zhu Xiaoping Zhou Hanhang Yin Lerong Hong An Luo Yandong Chen Hanting Peng 

机构地区：[1]College of Electrical and Information Engineering,Hunan University,Changsha 410082,China [2]School of Electrical and Information Engineering,Changsha University of Science and Technology,Changsha 410114,China

出　　处：《Journal of Modern Power Systems and Clean Energy》2023年第6期1995-2002,共8页现代电力系统与清洁能源学报（英文）

基　　金：supported by the National Key Research and Development Program of China (No.2021YFB2400900);the Joint Funds of National Natural Science Foundation of China (No.U2166602);the National Natural Science Foundation of China (No.52207200);the Major Special Project of Hunan Province (No.2020GK1010)。

摘　　要：Earlier studies have reported some calculation methods for commutation failure fault level(CFFL) in line-commutated-converter based high-voltage direct current(LCCHVDC) system under single-line-to-ground(SLG) faults. The accuracy of earlier methods is limited because they only consider the commutating voltage drop and phase shift, while neglecting the DC current variation. Hence, this paper proposes a CFFL calculation method under SLG faults considering DC current variation, for better planning and designing of LCC-HVDC systems. First, the fault commutating voltage magnitude and phase shift are calculated. Then, the fault DC voltage during different commutation processes is deduced. Based on the commutating voltage magnitude and phase shift, and DC voltage during different commutation processes under SLG faults, the characteristics of CFFL with different fault time are demonstrated and analyzed. Next, the transient time-domain response of the DC current after the fault is obtained based on the DC transmission line model. Discrete commutation processes are constructed based on the commutation voltage-time area rule to solve the extinction angle under different fault levels and fault time. Finally, the CFFL is calculated considering the fault time, commutating voltage drop, phase shift, and DC current variation. The accuracy of the proposed method compared with the traditional method is validated based on the CIGRE benchmark model in PSCAD/EMTDC.

关 键 词：Commutation failure(CF) commutation failure fault level(CFFL) line-commutated-converter-based highvoltage direct current(LCC-HVDC) single-line-to-ground(SLG)fault 

分 类 号：TM862[电气工程—高电压与绝缘技术]