Abstract:After the 500kV Central-Tibet interconnection project was put into operation, the Tibet Power Grid and the Southwest Power Grid were integrated to solve the problem of power shortages that have long plagued Tibet. However, due to the low level of stability of long-chain AC channels and the interaction of Chaila HVDC and AC channels, the Tibet Power Grid has created new security and stability problems. This paper analyzes the typical security problems existing after the operation of the Central-Tibet interconnection project, such as the impact of the interaction between the Chaila HVDC and AC channels, the impact of the load characteristics of the Tibet Power Grid on the isolated network in Tibet, and the impact of the 500/220kV electromagnetic ring network. And discuss its security and stability control strategy.