The damping of modal 3 is weakest, which is under the risk of subsynchronous resonance divergence in most operation regions.
In order to suppress subsynchronous resonance, four parallel SVC are installed on the high side of the Jinjie plant's step-up transformer's bus bar and each SVC has a capacity of 100 MVar.
Table 1 shows that modal 3 contains negative damping under the four kinds of operating conditions when there is no SVC, which would cause subsynchronous resonance. But all modals contain damping when SVC controlled by SSDC is installed.
This indicates that subsynchronous resonance has been suppressed effectively.
 IEEE Committee Report, "Reader's guide to subsynchronous resonance," IEEE Transactions on Power Systems, vol.
 IEEE Subsynchronous Resonance Working Group, "Countermeasures to subsynchronous resonance problems," IEEE Transactions on Power Apparatus and Systems, vol.
Mirshekar, "Optimal control of SVC for subsynchronous resonance stability in typical power system," in Proceedings of the IEEE International Symposium on Industrial Electronics (ISIE '01), vol.