Rajasthan Technical University

About: Rajasthan Technical University is a education organization based out in Kota, Rajasthan, India. It is known for research contribution in the topics: Photovoltaic system & PID controller. The organization has 716 authors who have published 1084 publications receiving 4530 citations. The organization is also known as: RTU.

Selection of Membership Functions Based on Fuzzy Rules to Design an Efficient Power System Stabilizer

Abstract: This paper presents an evaluation of membership functions on a single-machine infinite-bus and two-area four-machine ten-bus power system with power system stabilizers (PSSs). The PSS is added to an excitation system to enhance the damping during low-frequency oscillations. In this paper, the system is analysed for fuzzy logic power system stabilizer (FPSS) with different membership functions (MFs). The speed deviation ( $$\Delta \omega$$ ) and acceleration ( $$\Delta \dot{\omega }$$ ) of the rotor of a synchronous generator are taken as the input to the fuzzy logic controller to improve small signal stability by enhancing damping. The effect of these variables on damping at the generator shaft mechanical oscillation is very significant. The stabilizing signals were computed using the different fuzzy membership functions in the Mamdani inference system. The general membership functions under consideration are triangular, trapezoidal, Gaussian, bell, sigmoid and polynomial types. The performance of the fuzzy logic PSS with different membership functions is compared to get best-suited MF to design an FPSS. The best-performing MF is found based on simulation study with both power systems and with varying no. of linguistic variables as well. It is found that, If the number of linguistic variables is 3 or 5, the preferred best-suited membership function appears as the Gaussian type, while with increased linguistic variables as 7 or above, then the triangular MF is preferable as the performance is better in comparison with Gaussian MF.

Power law-based local search in spider monkey optimisation for lower order system modelling

Abstract: The nature-inspired algorithms NIAs have shown efficiency to solve many complex real-world optimisation problems. The efficiency of NIAs is measured by their ability to find adequate results within a reasonable amount of time, rather than an ability to guarantee the optimal solution. This paper presents a solution for lower order system modelling using spider monkey optimisation SMO algorithm to obtain a better approximation for lower order systems and reflects almost original higher order system's characteristics. Further, a local search strategy, namely, power law-based local search is incorporated with SMO. The proposed strategy is named as power law-based local search in SMO PLSMO. The efficiency, accuracy and reliability of the proposed algorithm is tested over 20 well-known benchmark functions. Then, the PLSMO algorithm is applied to solve the lower order system modelling problem.

A robust image watermarking technique using 2-level discrete wavelet transform (DWT)

Abstract: The exponential growth in digital data over the internet has increased the requirement of a robust and high quality watermarking techniques. In general, the image watermarking techniques embed the binary or grayscale watermark into the cover image or into many multimedia images. In this method, variable visibility factor is used for the insertion of watermark into the low frequency component of the host image. In this paper, DWT-based image watermarking is proposed using level i.e. 2-level and also its parameters such as PSNR and NCC are compared with respect to 1-level DWT. The invisibility of watermarks generated using proposed method is depicted in the simulated results.