Design of Non-Uniform Sampled-Data Load Frequency Control Scheme for Multi-Area Wind Power Integrated Power System and Its Application in IEEE 39-Bus System

Integral quadratic constraint (IQC) provides a general framework for analyzing the robustness of uncertain systems, which requires describing the system as an interconnection of nominal linear time-invariant system and perturbation. The non-uniform sampling and penetration of wind power have a negative impact on the frequency of power system. In order to ensure the safe operation of power system, in this paper, by applying IQC stability analysis, a load frequency control (LFC) scheme is developed for the non-uniform sampled-data power system with wind power. Firstly, considering both the non-uniform sampling and wind power, a LFC model for power system is established. Then, from the discrete-time viewpoint, a feedback interconnection of nominal linear time-invariant discrete-time system and uncertain operator is constructed to describe the studied LFC scheme. Next, in order to quantify the performance of the designed controller, introduce the exponential decay rate, and establish a transformed interconnection by defining a scaling operator. After that, based on the IQC theory, the exponential stability criterion of the original model is proposed based on linear stability of transformed interconnection. And the LFC scheme is designed by dealing with the nonlinear term of linear matrix inequality in the obtained stability conditions, which can provide the faster frequency response and larger sampling period for the power system with wind power. In addition, a heuristic algorithm is presented to calculate controller gains. Finally, case studies are conducted to illustrate the validity and advantages of the presented LFC scheme based on the one-area, two-area and three-area LFC system and the IEEE 39-bus system.