Novel fault current-limiting scheme for MMC-based flexible HVDC system

• Main Authors: Yueyang Ma, Guibin Zou, Shenglan Song, Jianbao Guo, Zhanjun Gao
• Format: Article
• Language: English
• Published: Wiley 2019-02-01
• Series: The Journal of Engineering
• Subjects: fault currents; power overhead lines; fault diagnosis; power electronics; power transmission control; HVDC power transmission; HVDC power convertors; MMC-based flexible HVDC system; flexible direct current transmission technique; power engineering projects; multilevel converter; rapidly rising fault current; high-voltage direct current system; symmetrical bipolar MMC–HVDC system; serial controllable power electronics; novel current-limiting scheme configuration; operation principles; symmetric bipolar MMC–HVDC system model; fault current-limiting scheme
• Online Access: https://digital-library.theiet.org/content/journals/10.1049/joe.2018.8871

Currently, the flexible direct current transmission technique becomes a research focus around the world, and be applied in power engineering projects gradually. However, due to the topology of the modular multi-level converter (MMC), a rapidly rising fault current will appear in case of the fault on the DC side, which constraints the development of MMC-based flexible high-voltage direct current (MMC–HVDC) system. To restraint the fault current, this paper proposes a novel fault current-limiting scheme for symmetrical bipolar MMC–HVDC system, which consists of a current-limiting resistance and dozens of serial controllable power electronics in parallel with the current-limiting resistance. The current-limiting resistance is designed to reduce the fault current and the requirement for the direct current circuit breaker (DCCB) capacity. The novel current-limiting scheme configuration and operation principles are analysed. Finally, a symmetric bipolar MMC–HVDC system model is constructed, and simulation results show the feasibility of the proposed fault current-limiting scheme.