Negative effect and principle of TCSC to traditional emergency control

With the development of power electronic technology, flexible AC transmission systems (FACTS), such as thyristor controlled series capacitor (TCSC) are widely used. Not only enhancing the control capacity of the system, but also increasing the complexity of the power grid control. At the same time the completed UHV AC/DC hybrid power grid puts forward new requirements for power grid operation and control. In this paper, based on the extended equal-area criterion (EEAC) introduced system of the first swing and reverse swing instability mechanism. Aimed at the access of TCSC to power grid, the problem of lacking of existing security control methods in some system failures that may worsen the problem of unstable modes is furtherly studied. It is noted that the access of TCSC may have negative effects on the security and stability of the power grid. The effects of TCSC will have on the system security and the traditional emergency control are analyzed by the actual power grid data, as well as the corresponding solutions.