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Title: Dynamic Model of Turbine System of Micro Hydroelectric Scheme for Stability Analysis
Author(s): Uzma Nawaz, Muhammad Naeem Arbab, Gul Rukh
Pages: 1-6 Paper ID:142406-7979-IJECS-IJENS Published: December, 2014
Abstract: Appropriate modeling of hydro system including penstock, hydro-turbine and the speed governing system play a very significant role in studying dynamic performance of micro hydro power plant. This paper briefly reviews the differential equations for hydro system and based on the differential equations, a transfer function is obtained. The analytical method for calculating the flow of water through the penstock uses equation of motion and continuity. These equations used arithmetical and graphical methods for solving transient stability problems. The turbine system can modeled by using the concept of mechanical rotational system, comprising of rotational inertia, damper and torsion spring. The differential equation of hydro turbine torque is derived and dynamic mode is built. Simulation results are compared with actual hydroelectric plant. Simulation results show a close similarity with the actual system.
Keywords: Dynamic performance, hydro-turbine, Penstock, transients.
Full Text (.pdf)  International Journals Of Engineering and Science | 364 KB
Title: A 3.5 - 4.5GHz Flat Gain UWB LNA
Author(s): Heba A. Shawkey
Pages: 7-11 Paper ID:141506-8383-IJECS-IJENS Published: December, 2014
Abstract: Ultrawideband (UWB) radio technology has inherent characteristics that make it highly suitable for low power applications. This paper shows the design of a low noise amplifier (LNA) for 3.5-4.5GHz UWB frequency range. The proposed LNA consists of three stages, a cascode LNA an inductive inter-stage network and a common source amplifier with a shunt feedback resistor. The proposed LNA has a peak gain (S21) 21.7 dB with 0.9dB ripples in the designed frequency range and minimum input and output return losses (S11, S22) -8.5 and -11 dB respectively. The proposed LNA has a minimum noise figure (NF) 1.6 dB, input third-intercept point (IIP3) of -18 dBm, 1-dB compression point of -23 dBm. The proposed LNA is designed at UMC 130nm CMOS technology and consumes 4.8mW for 1.2 V power supply.
Keywords: LNA, inductive inter-stage, shunt feedback, low NF, Ultra-Wideband (UWB).
Full Text (.pdf)  International Journals Of Engineering and Science | 517 KB