Nonlinear adaptive control of TCSC to improve the performance of power systems

The installation of thyristor controlled series compensation (TCSC) is planned in the Yimin-Fengtun 500 kV transmission lines of the Northeast China power system. To improve the transient stability and dynamic performance of the system, the authors present a nonlinear control scheme for the TCSC. The control scheme is derived by employing a nonlinear theory, the differential geometry theory. Thus, it can reflect the nonlinearity of power systems and has better adaptability. To reduce the influence of operation limitations of the TCSC equipment, such as limitation owing to the voltage protection of the metal oxide varistor (MOV), or the firing-angle of thyristors, an adaptive strategy of choosing parameters of the controller is applied. Thus, in any power transfer level, satisfactory performance of the power system can be acquired with the control scheme. A local control approach is also proposed so that all input variables can be obtained locally and easily. Simulations have proved the effectiveness of the nonlinear adaptive control strategy