Open AccessEnhanced line commutated converter with embedded fully controlled sub‐modules to mitigate commutation failures in high voltage direct current systems
Author(s) -
Ni Xiaojun,
Zhao Chengyong,
Guo Chunyi,
Liu Hang,
Liu Yuchao
Publication year - 2016
Publication title -
iet power electronics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.637
H-Index - 77
eISSN - 1755-4543
pISSN - 1755-4535
DOI - 10.1049/iet-pel.2015.0421
Subject(s) - commutation , thyristor , transient (computer programming) , engineering , voltage , line (geometry) , power (physics) , high voltage direct current , hvdc converter station , electrical engineering , electronic engineering , direct current , control theory (sociology) , computer science , control (management) , quantum mechanics , physics , geometry , mathematics , artificial intelligence , operating system
An enhanced line commutated converter (E‐LCC) with embedded fully controlled sub‐modules (SMs) to mitigate commutation failures (CFs) in high voltage direct current (HVDC) system is proposed in this study. The main feature of E‐LCC is that each arm is composed of thyristor valves and series connected fully controlled SMs. The operation modes and voltage–current stresses of embedded SMs in E‐LCC are studied. Then the control strategy, including the pre‐charging scheme of SMs and the coordination control method between the thyristor valves and the SMs, is presented. On the basis of the derived equivalent commutation circuit of E‐LCC‐based HVDC (E‐LCC‐HVDC), the dynamic characteristics of the commutation process are investigated. Then, the impact of E‐LCC‐HVDC on CFs mitigation is theoretically analysed. To validate the proposed E‐LCC‐HVDC, the simulation study is conducted in the electromagnetic transient simulation program PSCAD/EMTDC. The results show that with the embedded SMs, the proposed E‐LCC‐HVDC has the ability to mitigate the CFs and alleviate the power interruption during the AC faults effectively. Furthermore, the theoretical analysis and the presented control method for E‐LCC‐HVDC are also validated.