Nonlinear multitarget H∞ controller for thyristor-controlled series compensation

Thyristor-controlled series compensation (TCSC) has been planned for the L1-Shuanghe 500 kV transmission lines of the Three Gorge project in Central China, which will be the world´s largest hydropower station when completed. To achieve a number of benefits, such as improving the transient stability and dynamic performance of power systems and enhancing the power transfer capability of long transmission lines, a novel nonlinear multitarget H_∞ controller for TCSC in a multimachine power system is presented. With this new control scheme the effect of exogenous disturbances on the system is attenuated efficiently. The TCSC can achieve better adaptability to the variation of the system operating mode. The designed control law has engineering practicality since the variables are local measurements. Simulations performed on the Three Gorge transmission power system demonstrate that the proposed nonlinear multitarget H_∞ controller for TCSC is more effective than other types of TCSC controller for improving both dynamic performance and transient stability, thus enhancing the power transfer capability of the long transmission lines of the Three Gorge power system