Nonlinear Impedance Control of TCSC Based on Immune Feedback Law

Whether or not the TCSC device can be implemented in power system largely depends on its impedance control effect. In this paper, the bad robustness of the traditional PID control when ordering different impedances to a same level is analyzed. Moreover, a new nonlinear PID control method for the impedance control is presented by combining the immune feedback law with the conventional PID control. The structure of the PID controller corresponding to the proposed method is the same as the traditional PID controller except adding an immune feedback block. Simulation results from the traditional method and the newly proposed one have been compared, which show that the proposed method can quickly drive the output impedance to the desired level with less overshoot. The proposed method is feasible for practical application since it has good dynamic and static performances.