Stability of HVDC systems through transient energy storage

Successful integration of offshore wind power via VSC based HVDC transmission systems into the existing power grid requires a full understanding of the inherent potential and possibilities to keep this complex system stable under worst case conditions. These conditions include in particular large onshore system disturbances decreasing the power transfer capacity of the grid suddenly to below the power actually being generated by the wind farm. This paper deals with the effect of a battery storage plant added at the PCC to draw excess power providing an improved balance between the power supplied by the wind farm and the total power consumed at the PCC. The study is performed on the PSCAD/EMTDC digital simulator.