SUBSYNCHRONOUS RESONANCE FOR CONNECTION OF TWO AC SYSTEMS WITH HVIDC LINK

Fast growth of consuming electrical energy and the necessity of its transmission yields construction of transmission lines with high capacity and long distances. Nowadays HVIDC transmission systems dueto economical advantages fortransmission of electrical energy at large scale and for further distances" have found more applications. Recently transmission & interconage of electrical energy has been discussed between Iran and Turkey. This paper first surveys on HVIDC & Turbine - Generator torsional interactions and then studies analytically production of subsynchronous resonance by HVIDC and shows how the damping of torsional oscillations by SSDC. It has been shown that HVIDC systems can interact significantly with torsional modes of oscillation of turbine shafts. The interaction is sensitive to many system parameters" most significantly the transferred DC power" the firing angle of the converter and the control mode -of,tbe HVIDC system.