Stability analysis of load frequency control for power systems with large delay periods based on switching technique

This paper investigates the problem of load frequency control (LFC) for power systems with large delay periods (LDPs), which is often present in practical power systems and makes them unstable. LFC for power systems with LDPs has been modeled as switched delay systems, which include an unstable subsystem caused by LDPs. The switching strategy is used to deal with the stability problem of LFC for power systems with LDPs and stability criteria are proposed under the constraint conditions of the length ratio and the frequency of LDP to ensure power systems exponential stable. Finally, the relationship between the gains of PI controller and delay margin is studied and the simulation results show that the proposed method is effective.