National Institute of Technology, Meghalaya

About: National Institute of Technology, Meghalaya is a education organization based out in Shillong, India. It is known for research contribution in the topics: Control theory & Electric power system. The organization has 503 authors who have published 1062 publications receiving 6818 citations. The organization is also known as: NIT Meghalaya & NITM.

Flow Analysis of Vortex Generators in the Shroud of a Horizontal Axis Wind Turbine

Abstract: The abstract should summarize the contents of the paper in short terms, i.e., 150–250 words. Wind energy is one of the most widely available energy sources. It can be extracted using a wind turbine. Efficiency of a wind turbine depends on factors such as incoming air velocity and its geometric parameters. Wind velocity varies with respect to location and the seasons. A higher approaching velocity means higher power output. In this study, shroud of a wind turbine is introduced. Shroud is an enclosure over the wind turbine blades. In the existing work, when air passes over the shroud, the approaching wind velocity increases up to 1.8 times due to its geometrical configuration. In this work, the effect of diffuser shape shroud on the approaching wind velocity is studied with vortex generators inside, to enhance the mass flow rate of air with the aid of pressure drop. The obtained pressure drop along the flow direction is not sufficiently high to overcome the losses in mass flow due to the obstacle provided by the vortex generator’s body.

Harmonics Elimination in 24 Pulse GTO Based STATCOM by Fuzzy Logic Controller with Switching Angle Optimization using Grey Wolf Optimizer

Abstract: There is a new approach of multilevel convertor we can use 24-pulse gate turn-off thyristor based voltage source converter configuration which consist of one 24-pulse GTO convertor as main element. A 24-pulse cofiguration normally generates a output voltage waveforms which is alternating in nature, contains 23th, 25th,,,47th,49th harmonics which is not desirable. The application of this configuration is reduced voltage harmonics of higher order. Finally reduced THD% level. In this paper, a new model of 3-level, 24-pulse configuration of rating 33kv, 50MVAR, with advance pulse width modulation technique, PI-controller used to control pulse generator circuit, DC energy stored in a Capacitor bank and two magnetics are designed to exchange the power from STATCOM circuit to transmission system and the same time can optimized the Harmonics of lower order as well as higher order. In this the configuration the DC side voltage is controlled by implementing a fuzzy PI controller. This compensate transient variation, with varying capacitor side voltage. In this work the fuzzy logic supervision is proposed to minimal THD% from 25% to 2.62 % which remarkable advantage of this configuration.

Linked Simulation Optimization Model for Evaluation of Optimal Bank Protection Measures

Abstract: This work proposes a new methodology for determination of cost effective river training work using groynes. The proposed methodology links the two dimensional (2D) hydrodynamic model with genetic algorithm based optimization model. The hydrodynamic model uses Beam and Warming implicit finite difference scheme for solution of the governing equations of unsteady free surface flows in general coordinate system. The optimization model minimizes the total construction cost of the groyne system required for achieving desirable training of the river. Binary coded GA is used for solving the proposed optimization problem. The efficiency and field applicability of the developed model is evaluated using two different test problems. The first problem considers a hypothetical meandering channel and the second problem deals with a vulnerable reach of river Brahmaputra in India. The performance evaluation of the model shows potential of the developed model for field application.

Estimation of Fundamental Frequency of Noisy Speech Signals using Correlogram based on Subband Filtering

Abstract: Estimation of the fundamental frequency (FO) is a difficult task under the colored noise environment In this work, an algorithm for estimation of the fundamental frequency of speech signal is proposed based on multi-channel comb filtering and correlogram for noisy speech signals The noisy speech signal is decomposed into four bands using wavelet transform The comb filter is applied on each decomposed subband signal to enhance the peaks in each correlogram For obtaining the correlograms, the autocorrelation is computed for each subband The comb filter is defined using the raised cosine function with interpeak frequency ranges from 25 to 500 Hz Comb filter channels are needed to match the harmonics of the fundamental frequency and these channels are selected based on the harmonic to subharmonic ratio The proposed method is evaluated using the CSTR database The performance of the proposed method is compared with the RAPT, YIN, Cepstrum and SHR algorithms in terms of gross pitch error (GPE) The simulation results show the performance of the proposed algorithm is superior in different noise environments compared to existing methods