control application in 1997 and named CARLA . CARLA has numerous advantages such as high speed convergence; however, it requires pre-specified decision variables variation limits. These limits can be obtained using any simple method such as local linearization. Therefore, CARLA method requires system dynamics in initial step and this property count as disadvantage; moreover, these system equations can not be achieved easily for any application. DARLA has similar properties due CARLA such as fast convergence, system dynamics independency, considering fully nonlinear characteristic and so on. Consequently, as indicated by proposed method by combining DARLA and CARLA methods we can approach to an automatic designing structure of PSS. This proposed method called CDCARLA 3 and has all of above worthwhile properties. For evaluating performance of CDCARLA designing method, stabilization behavior of designed Takagi-Sugeno Fuzzy PSS simulated and compared with two IEEE standard PSS (PSS2B and PSS4B) for single machine infinite bus power system model. The simulation results shows that proposed method have a better performance against other PSS for various power system electromechanical disturbances.The structure of paper is as follows: in section II Takagi-Sugeno fuzzy PSS structure presented, section III describe power system model, in section IV the novel design methodology has been described, section V shows the simulation results of proposed design method, and section VI conclude the paper. II. POWER SYSTEM STABILIZERIn this paper, a Takagi-Sugeno Fuzzy Logic PSS (TSFLPSS) is designed. This TSFLPSS has two input variables: rotor speed deviation (Ato ), and accelerating power (Atp = p p ) For both input variables, three triangular membership functions have been considered as shown in Fig. 1.Abstract. One of the effective methods for damping oscillation due to occurring disturbances in power systems and keeping synchronism of machine is using power systems stabilizers (PSS) in excitation circuits of synchronous generators. In past decades, designing and tuning of PSS have been interested for many researches and scientist, because inaccurate setting of PSS not only cause damping of oscillations but also may help to amplify instability and lead to loss of synchronism. In this paper, Takagi-Sugeno Fuzzy logic PSS designed with novel method call CDCARLA have been proposed for single machine-infilnite bus (SMIB) power system model and compared with two IEEE standard PSS. Simulation results shows that designed PSS has better performance and more robustness than other PSSs. Brilliant properties of CDCARLA method is that it does not require to system dynamics and any other information about power system. In addition, this method does not ignore any nonlinear feature of power system; consequently, CDCARLA method can be one of automatic design method.

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