The occurrence of low-frequency electromechanical oscillations is a major problem in the effective operation of power systems. The scrutiny of these oscillations provides substantial information about power system stability and security. In this paper, a new method is introduced based on a combination of synchrosqueezed wavelet transform and the stochastic subspace identification (SSI) algorithm to investigate the low-frequency electromechanical oscillations of large-scale power systems. Then, the estimated modes of the power system are used for the design of the power system stabilizer and the flexible alternating current transmission system (FACTS) device. In this optimization problem, the control parameters are set using a hybrid approach composed of the Prony and residual methods and the modified fruit fly optimization algorithm. The proposed mode estimation method and the controller design are simulated in MATLAB using two test case systems, namely IEEE 2-area 4-generator and New England-New York 68-bus 16-generator systems. The simulation results demonstrate the high performance of the proposed method in estimation of local and interarea modes, and indicate the improvements in oscillation damping and power system stability.
Summary
Operation and control of large‐scale power systems is a complex task. Since the primary purpose of power system stabilizer (PSS) units is damping of local and interarea modes, identification of network electromechanical oscillatory modes for designing PSS is very important. In this research, continuous wavelet transform (CWT) was used to study low‐frequency electromechanical oscillations of power systems. The complex Morlet mother wavelet and guidelines for the selection of center frequency, bandwidth parameters, and scaling factor were used to estimate reliable modal specifications of the power system. After estimation of power system modes, the Prony method was used to identify the transfer function residue. Thus, the parameters of PSS were calculated by the residual method. In order to improve damping and meet the constraints of the proposed PSS parameters, the sequential quadratic programming algorithm was used as an optimization method. Finally, with the help of MATLAB and PST softwares, modes estimation methods and the proposed controller design approach was simulated on the two known test case systems, IEEE two‐area, four‐generator and 68‐bus, 16‐Gen test cases. The simulation results show efficacy and good performance of the proposed PSS design method to improve damping and small signal stability of the systems.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.