The World’s First-ever ±800kV Modular Multilevel Converter Valve has been Developed

One of the China’s largest power equipment suppliers – TBEA (Tebian Electric Apparatus) has recently developed the world’s first-ever extra-high voltage (EHV) modular multilevel converter (MMC) valve. It meant that the voltage level of MMC has been brought up from ±350kV to ±800kV, and the capacity has been increased from 1000MW to 5000MW. A new era of HVDC has been opened.

Converter valve is the heart of HVDC, playing a key role in making conversion between AC and DC power, and it is the most technical challenging part in the main equipment of HVDC. Through participating in National key research and development program of China (2016YFB0901002, led by China Southern Power Grid), the research team from TBEA have spent the last 9 months (since September 2016) on carrying out comprehensive and in-depth analysis, prototyping and experimental verification on key technology, equipment and engineering integration design. Now, the team’s effort is being paid-off by announcing the successful development of the world’s first-ever ±800kV MMC valve with all the type tests specified in IEC 62501-2014 passed (Parameter design and type test requirements are provided by China Southern Power Grid).

The MMC valve of TBEA employs the technology of MMC-Uninterrupted developed by TBEA. The MMC-Uninterrupted is able to keep un-interrupted operation during DC faults. It successfully solves the difficulties such as self-clearing of DC faults and restoring of the system, operation under reduced DC voltage and online bypassing/inserting of valve group when applying the MMC technology in DC overhead line transmission. It provides solid technology foundations for constructing overhead line MMC-HVDC,N multi-terminal HVDC system and DC grid.

The EHV MMC opens new ways for bulk power integration of renewable energy through long distance power transmission.