Further Stability Analysis for Load Frequency Control of Power Systems with Time-Varying Delays

This paper studies the stability problem of load frequency control (LFC) of a single area power system with communication delays both from remote measurements to the control centre and from control centre to generator units. The closed-loop LFC system with two transmission delays in communication networks can be expressed as the linear system with two additive time-varying delays. A stability criterion is derived via an affine second order Bessel-Legendre free-matrix-based inequality and Lyapunov stabiliity theory application. The stability criterion is in the form of linear matrix inequality (LMI), which can be easily solved via the MATLAB LMI-toolbox. Compared with some previously published results, the stability criterion in this paper is less conservative. Finally, an application of the LFC for a single area power system is presented to show the effectiveness of the proposed approach.