PID controller in load frequency control of power systems and tuning of its parameters by symbiotic organisms search algorithm

In this study, the application of Load Frequency Control (LFC) with separate features of a non-linear two-area thermal power system and a multi-source power system with different power generation sources such as thermal, hydro and gas power plants is studied. PID, which is a simple structured (Proportional-Integral-Derivative) controller has been used to increase the LFC performance of these electrical generating systems, and a new objective function has been proposed to obtain the most suitable values of PID controller parameters. As an optimization technique, the recently proposed, known for its strong structure symbiotic organisms search algorithm (SOS) was used. All interconnected electric power systems with LFC control application are designed in MATLAB/Simulink environment and SOS is encoded in MATLAB/m-file environment. Performance of the proposed approach was first tested in a linear two-area non-reheat thermal power system and a non-linear two-area governor dead band non-reheat thermal power system. Then, multi-source single-area power system, multi-source two-area power system with and without high-voltage direct current (HVDC) link were tested. In order to prove the contribution of the study to the literature, the results obtained from each system were compared with the results suggested in the relevant literature studies. According to the comparison results, it was seen that there was a great improvement in the frequency change and tie-line power change curves in the connection line with the PID controller adjusted using the SOAA technique and the proposed objective function. So, it has been demonstrated in this thesis that the proposed approach, despite ists simplicity, can be a good alternative to the literature works.