Delay Scheduling to Improve Power Oscillation Damping in the Presence of Random Delays

Using a conservative stability analysis to design a time delay system controller usually cause a devaluation on the actuator performance. In addition, the results obtained considering deterministic stability criteria may not be reliable due to the existence of random delays. Whenever the feedback loop of a power system oscillation damping control system receives remote signals through communication networks, we face a POD system with random delays namely POD-RD system.  In this paper, a new design approach to promote the performance of a POD-RD control system is proposed based on the delay scheduling control signal method. This is a two-step method for implementation. In the first step assuming the average value of the communication random delays, the controller''''s parameters and also delay parameter of the control signal are determined as initial values by minimizing sperctral abscissa of the closed loop system. In the next step, to include impact of the communication random delays, a repetitive procedure is proposed to determine the optimal value of the delay parameter of the control signal and also the controller''''s parameters. The objective of the optimization model is to minimize the spectral abscissa and the defined second order moment. The feasibility of the proposed method is evaluated by doing a number of simulations on the standard four-machine test system.The results reveal that the method can make a robust performance in the studied system.