ISSN 2394-3777 (Print) ISSN 2394-3785 (Online) Available online at www.ijartet.com International Journal of Advanced Research Trends in Engineering and Technology (IJARTET) Vol. 4, Issue 5, May 2017 All Rights Reserved © 2017 IJARTET 7 Simultaneous Design of PSS and FACTS based Power Oscillation Damping Controller Using GA and ANFIS Techniques Sobha Manakkal 1 , R. Sreerama Kumar 2 , Saly George 3 Professor, Department of Electrical and Electronics Engineering, Mohandas College of Engineering and Technology, Trivandrum, India 1 Professor - Department of Electrical and Computer Engineering, King Abdulaziz University Jeddah, Saudi Arabia 2 Professor, Department of Electrical and Electronics Engineering, National Institute of Technology, Calicut, Kerala, India 3 Abstract: An adaptive Neuro- Fuzzy Inference System (ANFIS) based Flexible AC Transmission System Power Oscillation Damping controller (FACTS POD) is proposed in this paper. The controller is tuned with Genetic Algorithm (GA) for coordination with Power System Stabilizer (PSS) to damp the low frequency oscillations in power systems. The work considers PSS installation on optimum machines using (sensitivity of PSS effect) SPE approach for damping the local modes of oscillation and the ANFIS based FACTS POD is considered for damping the inter-area mode of oscillation. A hybrid learning procedure is adopted to adapt the initial fuzzy parameters of the proposed POD controller for desired damping performance. The input-output data pairs for training the adaptive network is generated by using the GA based design procedure. The proposed technique is employed for simultaneous design of PSS and FACTS POD for power oscillation damping support. The effectiveness of the proposed damping controllers is examined on the modified New- England system with Unified Power Flow Controller (UPFC) FACTS device and non-linear simulation results are presented. Keywords: ANFIS, FACTS POD, GA, low frequency oscillations, SPE approach, hybrid learning, UPFC. I. INTRODUCTION In multi-machine systems involving large number of machines and many interconnections, there are various modes of oscillations which include low frequency oscillations on account of local modes involving machines geographically near to eachother and the inter-area oscillations when power transfer among different geographically distinct areas takes place through weak tie- lines. [1-2]. The traditional approach to damp the local mode oscillations is the installation of PSS, to provide supplementary control action through the excitation system of generators [1]. Application of high power electronic devices has made the concept of FACTS feasible for power flow control, voltage control and also for enhancing the damping of low frequency electromechanical oscillations [3]. Various works have been done and published on the damping of power system low frequency oscillations with FACTS based damping controllers. Design of UPFC controllers and supplementary damping controller for stability enhancement with UPFC on a longitudinal power system is presented in [4]. Wang has proposed [5-6] modified linearized Phillips-Heffron model for low frequency oscillation study to include the various FACTS members and the model has been extended to multi-machine systems. Tambey.N and Kothari.M.L in [7] have presented designing of UPFC based damping controller using phase compensation technique. The relative effectiveness of modulating the various UPFC controller parameters for damping power system oscillations has been analyzed in the paper. In [8], the same authors have presented the design of UPFC based damping controller in multi-machine systems, in which simultaneous modulation of two UPFC control signals has been proposed. In all the above works, the controller design is done linearizing the system equations with respect to a nominal operating point. However, power networks are subjected to large variations in operating conditions due to development of real time market, emergency operating conditions as well as actions due to automatic devices. Hence the performance of the controller