Coordinated design of STATCOM and excitation system controllers for multi-machine power systems using zero dynamics method

FACTs devices are being used in transmission networks for increasing the power transfer limit and stability improvement. They also help damp out both local and inter-area low frequency oscillations. However, uncoordinated design of these devices with excitation systems may deteriorate the power system performance. Moreover, power system is a large, complex and nonlinear system, and the controllers that are designed based on linear control theories may have a detrimental effect on the system performance, especially when there are large disturbances occurring in the system. The design method of a nonlinear control technique, named zero dynamics is given in this paper to design the controllers of STATCOM and excitation systems coordinately for multi-machine power systems. This technique is able to provide the stability of both external and internal dynamic performances of the system. Simulations results clearly verify that the proposed method improves the power system stability.

► A new nonlinear control method for multi-machine power systems is presented.
► This method is used to design STATCOM and excitation system controllers coordinately.
► The stability of both external and internal dynamic performances is achieved.
► Different faults and loading conditions are considered to test the proposed method.
► It has a better dynamic performance in comparison with other methods.