HVDC transmission line for interconnecting power grids in India and Sri Lanka

In this paper, the proposed interconnection of Sri Lankan power system grid and southern regional grid of Indian grid is modeled using a simple VSC configurations based on HVDC transmission. The control implemented is made in such a way that this will allow power transmissions in either way. Therefore voltage vector PLL based control together with DC-link voltage regulation is implemented. Here the HVDC both end VSC are operated with very similar controls and the only difference is one is operated as main and the other operated as sub. The main VSC controls the power flow and other follow up the main. The proposed system is modeled using PSCAD/EMTDC. Whilst the Impact of frequency variation and sudden load rejection due to one of the grid system failure is being analyzed in this paper, the reactive power control at both ends VSC to support the voltage regulation is also being studied. Simulation results show as to how the transients due to frequency fluctuation and country blackout will impact the HVDC transmission line's operations.