Browsing by Author "Ghatak, A."

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A Time-Frequency Transform based Fault Detection and Classification Methodology for Transmission Lines
(Institute of Electrical and Electronics Engineers Inc., 2021) Ghatak, A.; Kishan, D.
The inevitable events in power systems such as faults should be detected and resolved quickly to maintain system reliability. This paper proposes a Time-Frequency transform (wavelet transform) based fault detection and classification methodology using current signals. The Daubechies wavelet has been used to extract the features of the current signals. The proposed method detects a fault using the first level decomposition coefficients using wavelet transform, while the fault is classified by using the maximum values of the detail coefficients and logical analytical techniques. The proposed methodology is validated on a test model developed in the MATLAB Simulink environment. The performance of the proposed methodology has been verified under different fault configurations for different fault locations, resistances and inception times. The algorithm is also validated for a load change at the time of fault inception. The results show that the proposed methodology is accurate and reliable in fault detection and classification and can help in taking appropriate decisions to enhance the reliability of power system. Â© 2021 IEEE.
Comparative Analysis of Maximum Power Point Tracking Algorithms for Standalone PV System Under Variable Weather Conditions
(River Publishers, 2022) Ghatak, A.; Pandit, T.; Kishan, D.; Raushan, R.
Renewable energy systems are becoming increasingly predominant in the current scenario, and Photovoltaic (PV) arrays are one of the most widely used renewable energy generation sources. The current-voltage characteristics of PV arrays are non-linear, necessitating the need for supervisory techniques in order to ensure that the array functions at maximum efficiency, which is performed by Maximum Power Point Tracking (MPPT) techniques. These techniques are categorized into classical, intelligent and optimization algorithms. This paper performs a comparative analysis between five different MPPT techniques belonging to these categories – Perturb and Observe (P&O), Incremental Conductance (IC), Fuzzy Logic Control (FLC), Particle Swarm Optimization (PSO) and Cuckoo Search Algorithm (CSA). A standalone PV system interfaced with a Boost converter is simulated on MATLAB Simulink for the performance evaluation of the MPPT techniques. Solar energy is extremely susceptible to changes in local weather conditions, mainly variations in solar insolation levels. The designed system is tested against a varying insolation profile in order to examine the robustness of the MPPT techniques, with their operation efficiencies showcased. © 2022 River Publishers.
Three-dimensional multihelical microfluidic mixers for rapid mixing of liquids
(2008) Verma, M.K.S.; Ganneboyina, S.R.; Vinayak, Rakshith, R.; Ghatak, A.
Rapid mixing of liquids is important for most microfluidic applications. However, mixing is slow in conventional micromixers, because, in the absence of turbulence, mixing here occurs by molecular diffusion. Recent experiments show that mixing can be enhanced by generating transient flow resulting in chaotic advection. While these are planar microchannels, here we show that three-dimensional orientations of fluidic vessels and channels can enhance significantly mixing of liquids. In particular, we present a novel, multihelical microchannel system built in soft gels, for which die helix angle, helix radius, axial length, and even the asymmetry of the channel cross section are easily tailored to achieve the desired mixing. Mixing efficiency increases with helix angle and asymmetry of channel cross section, which leads to orders of magnitude reduction in mixing length over conventional mixers. This new scheme of generating 3D microchannels will help in miniaturization of devices, process intensification, and generation of multifunctional process units for microfluidic applications. 2008 American Chemical Society.
Three-dimensional multihelical microfluidic mixers for rapid mixing of liquids
(2008) Verma, M.K.S.; Ganneboyina, S.R.; Vinayak Rakshith, R.; Ghatak, A.
Rapid mixing of liquids is important for most microfluidic applications. However, mixing is slow in conventional micromixers, because, in the absence of turbulence, mixing here occurs by molecular diffusion. Recent experiments show that mixing can be enhanced by generating transient flow resulting in chaotic advection. While these are planar microchannels, here we show that three-dimensional orientations of fluidic vessels and channels can enhance significantly mixing of liquids. In particular, we present a novel, multihelical microchannel system built in soft gels, for which die helix angle, helix radius, axial length, and even the asymmetry of the channel cross section are easily tailored to achieve the desired mixing. Mixing efficiency increases with helix angle and asymmetry of channel cross section, which leads to orders of magnitude reduction in mixing length over conventional mixers. This new scheme of generating 3D microchannels will help in miniaturization of devices, process intensification, and generation of multifunctional process units for microfluidic applications. © 2008 American Chemical Society.