Concept and Method of the Observability and the Controllability Measure of Subsynchronous Oscillation Modes

The rapid development of large-scale centralized utilization of wind power is bringing the problem of subsynchronous oscillation (SSO) much new concerns. It is of great significance to analyze its monitoring and suppression. The concept of the observability and the controllability in the field of control system can be used to analyze the monitoring and suppression of SSO. Therefore, in this paper, the definitions of the observability measure and the controllability measure are proposed from the angle of oscillation mode. The time domain expression of the measure is deduced and compared with participation factor and the residue method. Furthermore, in order to compare different dimensional signals and their response to different oscillation modes and control effects, the concepts of comprehensive observability measure and comprehensive controllability measure are proposed. Based on these concepts, a subsynchronous damping controller for doubly fed wind power generation system is designed. Finally, the effectiveness of the method is verified by case study.