Turkish Journal of Electrical Engineering and Computer Sciences




This paper proposes a fractional delay-dependent load frequency control design approach for a single-area power system with communication delay based on gain and phase margin specifications. In this approach, the closed-loop reference transfer function relies on the delayed Bode’s transfer function. The gain and phase margin specifications are established in order to optimize the reference model based on three time-domain performance indices. Here, a category of fractional-order model is employed to describe the single-area power system incorporating communication delay. The controller parameters are determined using the fractional-order system model and optimal closed-loop reference model. Then, a delay-dependent control mechanism is proposed to compensate for the communication delay variations. The proposed controllers are implemented in a single area power system with nonreheated turbine having communication delay and are compared with other controllers designed relying on identical frequency domain specifications. The performance analysis of the proposed approach is made against communication delay variations, model parameter variations, and nonlinearities, i.e. governer dead band and governor rate constraints. Furthermore, the scope of the analysis extends beyond a single-area power system to encompass a multi-area power system, illustrating the effectiveness of the proposed method. The outcomes demonstrate that the performance of the proposed controllers surpasses that of alternative control methods, they are more robust to communication delay changes as well as system model parameter variations, and they perform efficiently in the case of multiarea case study.


Fractional delay-dependent, load frequency controller, delayed Bode's transfer function, power systems with nonreheated turbine, single fractional order pole model, gain and phase margin specifications

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