Stability improvement in power systems with non-linear TCSC control strategies

In this paper, a non-linear control scheme for the TCSC (thyristor-controlled series compensator) to dampen power oscillations and to improve the transient stability of power systems is presented. Based on an one-machine-infinite-bus system, a non-linear mathematical model is established which is proven as an affine non-linear system. With the help of the feedback linearization technique, the affine non-linear model is exactly transferred to a linear model, and then the control scheme is designed for the TCSC based on the global linearization, where the input signal uses local measurements only. The effectiveness and robustness of the proposed non-linear control scheme are demonstrated with one-machine test system, where the TCSC modeling and power system simulations are performed by using the program system NETOMAC. In comparison with a conventional control scheme, significant improvements of dynamical performance in the test power system are achieved by the proposed non-linear control strategy for the TCSC.