Abstract
This paper discusses newly developed control strategies of a self-commutated converter applied to HVDC system. An upper and lower power-limited DC voltage control establishes high performance in a two-terminal HVDC system. A voltage margin method to reverse DC transmission power is also introduced. Even when the communication system is shut down, if required, DC transmission power can be changed with our proposed controls applied to the terminal control. Furthermore, the DC voltage control scheme with two-stage voltage control characteristic is presented for multi terminal HVDC system use. When one terminal is collapsed, the multi terminal HVDC system can be operated because of the proposed control characteristics.
Simulator studies were carried out to verify the proposed control performance in the two-terminal HVDC system and successful test results such as power reversal and a terminal start-up during other terminal operation are shown.
