Suggestion and feasibility study for a massively parallel back-to-back system

This paper presents a new concept for back-to-back (BTB) dc systems. The main feature of the proposed BTB is referred to as “massively parallel.” This massively parallel BTB system consists of a number of small or mediumcapacity inverter units that are connected in parallel. The concept of transmission power control using the massively parallel BTB is investigated using MATLAB for a case where a fault occurs. In addition, a method for modeling the proposed BTB in EMTP is investigated. The work presented in this paper shows that the proposed BTB system is very promising for large power system applications because the losses of the system are very small compared to conventional BTB using VSC (voltage source converter). The massively parallel BTB can keep operating even if an inverter unit fails, thus improving overall power transmission capability. © 2001 Scripta Technica, Electr Eng Jpn, 138(3): 34–42, 2002