Low-frequency Oscillation Stability Research Articles

Profit payment scheme for service created by hybrid controller of large-scale wind power generation system

The contribution of hybrid controller of large-scale wind power generation system (LWPGS) in system stability and profit is discussed throughout the paper. To this purpose, it is necessary to formulate the impact of high infiltration of wind turbines on the dynamic stability of power networks. A mathematical model of a multi-machine power network is developed first, based on which an extended small-signal stability analysis procedure is projected and discussed to handle the influence of LWPGS on oscillatory modes. This model is then applied for analyzing the damping impact of the LWPGS and ancillary service (AS) associated with its controller. After the model creation, the profit created by LWPGS hybrid controller as AS is analyzed by multi-objective optimization based on low-frequency oscillation stability criterion and generation cost. Two scenarios for the valuation of small-signal stability as an AS provided by LWPGS controller are considered. The study is based on a changed 16-machine 5-area network. The comparative analysis of the results is also presented to elucidate the suggested approach.

Allocation and design of power system stabilizers for mitigating low-frequency oscillations in the eastern interconnected power system in Japan

Low-frequency oscillations have been observed on trunk transmission systems in Japan, and have been the subject for studies in fields of operation, control, and devices by the many power system utilities. Power system stabilizers (PSSs) are very effective controllers in enhancing the damping of low-frequency oscillations, since the controllers can increase damping torque for inter area modes by introducing additional signals into the excitation controllers already equipped with generators. In this paper, allocation of PSSs in an interconnected power system with inter area modes has been determined by an eigenvalue analysis, and PSSs for the allocated generators have been designed by a frequency response method. The designed PSSs have been verified in a Japanese power system standard model. This test system is created as a standard model based on the trunk transmission systems in the eastern area of Japan, and reflects characteristic features of the real power systems; therefore, realistic allocation and design for enhancement of the stability of low-frequency oscillations have been verified.