Harmonic Characteristic Research On UHVDC Transmission System

On the basic of the worldwide and domestic research on the existing HVDC transmissionsystem simulation modeling and harmonic characteristic, this paper clouds a large number ofYun-guang UHVDC transmission system operation parameters and takes Yun-guang UHVDCtransmission system as an example to build a UHVDC system PSCAD/EMTDC simulationmodel. Based on the PSCAD/EMTDC simulation model of Yun-guang UHVDC transmissionsystem, the harmonic characteristic of UHV transmission system has been widely studied.The research on the harmonic characteristic of Yun-guang UHVDC transmission systemis mainly divided into two aspects, namely, harmonic research on steady state and transientfault. Among them, the harmonic characteristic research on steady state is divided into theharmonic characteristic of three common operation modes, namely unipolar metal loop mode,unipolar earth loop mode and bipolar operation mode. The harmonic characteristic researchon transient fault mainly includes UHVDC system commutation failure or pulse lost fault,ground fault of DC transmission line and ground fault of AC transmission line, includingsingle-phase AC ground fault and two phases AC ground fault.Through the harmonic characteristic research on Yun-guang UHVDC transmissionsystem, we get a more comprehensive understanding of the harmonic characteristic and makeseveral conclusions, it has certain guiding significance of improving the operation level ofUHVDC transmission system.