The concept of HVDC taps drawing small amount of power from HVDC lines to the rural places has been considered for several decades. Most of the earlier tap converters were limited by its loss, cost, reliability, and control difficulties. However, in this paper, the emerging modular multilevel converter (MMC) is adopted as the series HVDC tap, which reveals significantly improved performance and feasibility. Circuit structure and operating principle of this tap are presented, and the control considerations are also discussed. Simulations are given to demonstrate effectiveness of the MMC tap and the proposed control strategies. This tap topology is very promising to find practical use in future HVDC tapping applications.
- power tapping
- modular multielvel converters
- circuit structure
- tap topology