Energization study of five-terminal multi-level HVDC converter station

Impact of HVDC converter energization connected to muti-terminal hub on network performance is presented in this paper. Due to capacitors used in HVDC converter, its energization produces a higher inrush current causing a severe voltage dip in both the ac and dc systems potentially exceeding the allowable limits. Similarly dc cable and HVDC transformer energization also causes a higher inrush current that can damage the semiconductor devices used in the converter system. The paper discusses fundamental principles, energization schemes and pre-insertion resistors as a mitigation measure among other. A case study was selected and the results are presented under various grid-conditions.