基于MMC的半波长交流输电潜供电流抑制措施研究

半波长交流输电技术因其自身的特点在远距离输电场景中提供了一种解决方案，然而潜供电流的问题限制了半波长交流输电技术的发展和应用，现有的潜供电流抑制方案在半波长输电系统中应用时均存在不足。为了解决这一问题，本文总结了潜供电流的分布规律，在此基础上，提出了基于模块化多电平换流器（MMC）的潜供电流抑制措施，并进行了控制策略的设计以及参数的选取。此外，提出了分相投切无源元件来配合MMC工作从而减少MMC容量的方案。最后，在仿真平台对所提抑制措施进行了仿真验证，结果表明该措施可以有效地抑制半波长交流输电的潜供电流，加快熄弧速度，提高系统的故障恢复效率。

Study on Suppression Technique of Secondary Arc Current of Half-wavelength AC Transmission Based on MMC

Half-wavelength AC transmission (HWACT) provides an alternative for remote transmission scenario due to its characteristics. However, the problem of secondary arc current limits the development and application of HWACT. The existing techniques have drawbacks when applied in HWACT system. In order to solve the problem, the distribution characteristics of secondary arc current in HWACT are analyzed, based on it the suppression technique using modular multi-level converter (MMC) is proposed. The control strategy and parameters of MMC are designed to compensate secondary arc current in HWACT system. Furthermore, a compensation scheme is proposed to reduce the capacity of MMC by switching passive components independently. Finally, simulations are carried out in PSCAD/EMTDC to verify the proposed method. The results show that the proposed technique can limit secondary arc current in HWACT system, and speed up the arc extinction and improve the fault recovery efficiency of the system.