Indian Institute of Technology Palakkad&nbsp;(IIT Palakkad or IIT PKD) is a public autonomous&nbsp;engineering&nbsp;and&nbsp;research&nbsp;institute located in&nbsp;Palakkad,&nbsp;Kerala. It was&nbsp;one of the five new&nbsp;IITs&nbsp;proposed in the&nbsp;2014 Union budget of India. The campus was inaugurated on 3 August 2015. The institute has 94 faculty, 978 students, and 63 non-teaching staffs.

IT Palakkad currently offers four-year Bachelor of Technology (B.Tech) and two years MS programmes in 8 different engineering disciplines including&nbsp;Computer Science, Electrical, Mechanical, Civil among others.

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IIT Palakkad

Effective management of multiple real-Time transient events and unstable low-frequency oscillations in the modern power system has been a matter of concern to the Transmission system operators. This manuscript unifies the idea of transient event detection and localization with the analysis of the oscillation mode that accompanies these impulsive events. The paper employs Discrete wavelet transform (DWT) to segregate transient events from oscillatory behavior that follows these events. The paper also proposes a novel indicator for the classification of transient events based on the most affected signals in due course of the event. Empirical Mode decomposition (EMD) and Hilbert spectral analysis (HSA) are utilized on the PMU signals severely affected by the event and further examine the oscillatory modes succeeding the real-Time events. Oscillatory modes deduced from the above adaptive transformations are further categorized into three frequency bands based on power system control applications, thus helping operators provide efficient control actions. The novel methodology discussed in the paper has been applied to the IEEE 39 bus system with a dataset generated using the RTDS power system simulator and GTNETx2 based PMUs. © 2021 IEEE.

World University root node

Department of Electrical Engineering

2021 9th IEEE International Conference on Power Systems (ICPS)

A Novel Hybrid Algorithm for Event Detection, Localisation and Classification

The development of new smart grid technologies and the rising environmental concerns lead to increased penetration of green energy sources into the existing power grid. This increased penetration of renewable energy sources (RES) into the power system will affect system dynamics. This paper discusses the influence of integrating full converter-based renewable energy sources on different system stability indicators (SSIs) such as rate of change of frequency (ROCOF), frequency nadir, etc. Different test systems such as Kundur's two area model and IEEE-9 bus system are considered to evaluate the impact of different penetration levels of RES on power system stability indicators. The response of the system to common contingencies such as generator outage, load shedding, faults, etc. are studied using Dynamic Security Assessment Tools (DSA Tools) from Powertech Labs. It is observed that the post-disturbance dynamic behavior of a conventional synchronous generator-dominated system is significantly different from that of an inverter-dominated system and it is heavily dependent on penetration level, type of disturbance, type of RES, etc. © 2021 IEEE.

Impact of Different Penetration Level of Type-IV Renewable Energy Resources on Power System Dynamics

In this paper, we investigate the performance of the WiFi-based human presence detection (HPD) method using the two-dimensional convolutional neural network (2DCNN) and long-short term memory (LSTM) under generalized-room model and room-specific model learning environments with optimal 2DCNN and LSTM parameters. The HPD method is designed to classify the WIFi-data segment into a room with person (RWP) or a room without person (RWoP) using magnitude channel state information (CSI). The preprocessing is used to perform filtering and to split the recorded CSI data into blocks, and data preparation. We created the CSI database which consists of 33 hostel room datasets, 3 laboratory room datasets and 3 home room datasets for room specific models with support of 33 volunteers, by using the commercial WiFi device with single antenna. Based on the evaluation results under unseen datasets, cross-validation and room-specific models, we observe that the LSTM based HPD method had an average sensitivity, SE =91.70%, specificity, SP =89.60% and accuracy, ACC= 90.57% that outperforms the 2DCNN based HPD method (SE =89.93%, SP= 88.23% and ACC =88.96%). Further, the LSTM based HPD method had a processing time of 1.8 ms and model size of 934 KiloBytes whereas the 2DCNN based HPD method had a processing time of 2.9 ms and model size of 10470 KiloBytes. © 2021 IEEE.

Proceedings of the 13th International Conference on Electronics, Computers and Artificial Intelligence, ECAI 2021

Non-Collaborative Human Presence Detection Using Channel State Information of Wi-Fi Signal and Long-Short Term Memory Neural Network

This paper presents a hybrid method for detecting power quality events based on combined Hilbert transform and Fourier transform. The decision tree classifier has been implemented over the detection scheme to classify eight power quality disturbances. The proposed method extracts the envelope from the Hilbert transform (HT) and identifies the number of harmonic components present in the power quality (PQ) signal using the Fast Fourier transform (FFT) technique. To evaluate the proposed method, a standard database was created from the mathematical models and white Gaussian noise is added to the database with different noise levels. The relevant features, such as energy, kurtosis, minimum amplitude from the envelope, and the number of peaks from the Fourier magnitude spectrum are extracted. The features have been used to train the decision tree (DT) classifier and a classification accuracy of 99.30% is obtained. The robustness of the proposed algorithm is addressed on another synthetic database with different noise levels, and it achieves 99.27% overall classification accuracy. Finally, the proposed method is compared with recent techniques and achieves promising results in terms of classification accuracy. © 2021 IEEE.

2021 National Power Electronics Conference, NPEC 2021

Integrated Hilbert-Fast Fourier Transform approach for detection and classification of power quality disturbances

Though the advantages of direct Matrix-based Dual-Active-Bridge (MB-DAB) converters have been highlighted in recent literature, their complete set of modulation possibilities are yet to be analyzed. This holistic study of modulation modes is presented in the paper, which divulges the power transfer boundaries of possible modulation modes in the front-end half-bridge (FE-HB) and front-end full-bridge (FE-FB) MB-DABs, and highlights the acceptable modulation scheme(s). For an optimally designed 1 MVA modular MVAC-LVDC conversion stage of Solid-State-Transformer (SST), the FE-HB MB-DAB configuration proves to be a better alternative compared to FE-FB variant in terms of the power transfer boundaries, apart from the other topology related benefits highlighted in literature. Simulation results for modulation of the full-scale 1 MVA SST's 35.1 kW(pk) submodules validate the mathematical analysis. Further, a scaled-down 1.4 kW(pk) experimental validation verifies the FE-HB MB-DAB converter's working principle.

Modulation of Direct Matrix-Based Dual-Active-Bridge (MB-DAB) AC-DC Converters

This paper presents a new compact ultra-thin triple-band absorber which shows near-unity absorption in C, X and Ku-bands. It consists of an inductive stub loaded circular ring resonator and a flower-shaped resonating patch on top of 0.8 mm thin FR-4 grounded dielectric substrate. A transmission line equivalent is proposed, and circuit simulation response is in good agreement with the full-wave analysis. The unit-cell architect's 4fold symmetry makes it polarisation-insensitive for different polarisation angles in the azimuthal plane (= 0°) under normal incidence. Its good shows angular stability up to 45° under TE (75° under TM) incidences for all three frequencies. Surface current patterns are analysed at resonant frequencies to illustrate the mechanism behind the electromagnetic absorption. This design's novelty lies in the centre patch's dual-resonating behaviour, making this design compacted one. The absorber has low-profile nature with cell periodicity of 0.163λL and thickness 0.013λL, where λL is the lowest resonating peak wavelength. An X-band conventional MSA is fabricated on a thin FR-4 substrate. In-band RCS reduction (nearly 18 dBsm) of the antenna is verified after loading with the proposed absorber. The absorptivity peaks are optimised such that the same structure would be used in different applications like RF energy harvesting, RCS reduction and sensor applications. © 2021 Wiley Periodicals LLC.

International Journal of RF and Microwave Computer-Aided Engineering

Compact polarisation insensitive wide angular stable triple band absorber for RF energy harvesting, RCS reduction, and sensor applications

This work describes an Ultra-Wideband (UWB) antipodal antenna utilized for the microwave imaging of a breast phantom. The designed antenna consists of stubs arraged at a particular length apart to widen the bandwidth and an elliptical patch at the aperture of the structure is placed to improve the performance at high frequencies. The proposed antenna achieves a bandwidth from 1.3 GHz to around 14 GHz with good impedance matching as well. The designed antenna attains a peak gain of 10 dBi at 6 GHz and the proposed structure is utilized for the monostatic microwave imaging of the breast with two tumors using Synthetic Aperture Radar. © 2021 IEEE.

2020 IEEE MTT-S Latin America Microwave Conference (LAMC 2020)

Microwave Breast Imaging using Synthetic Aperture Radar Method utilizing UWB Antenna

This paper presents a new compact unit cell for reflection-type linear co to cross-polarization conversion. The metasurface is printed on a perfect conductor-backed dielectric substrate. The unit cell consists of double E-shaped resonators. The structure exhibits a broadband linear cross conversion from 6.46 - 14.07 GHz (7.61 GHz or 74.2 %) with a polarization conversion ratio (PCR) is &gt; 90 %. The converter response is found to be stable at a high incidence angle of &gt; 30°. Periodicity of the unit cell is 0.38 λ 0 , where λ 0 is the free space wavelength at the center frequency of the operating range. This proposed converter can be used for stealth technology for radar cross-section (RCS) reduction. At frequency 9.8 GHz, the 4 x 4 array of the converter reduces the RCS by more than 21 dB for both monostatic and bistatic conditions.

IEEE Xplore

Double E-Shaped Reflection Type Polarization Converter For Radar Cross Section Reduction

In this work, radio frequency (RF) micro-electromechanical system (MEMS)-based frequency and bandwidth tunable bandpass filter is presented for application in 24 GHz Doppler radar transceivers. The filter is fabricated on 635 μm alumina substrate using surface micromachining process. Total area of the filter is only 2.8 mm2 excluding bias lines and pads. Functional building blocks of the proposed filter are fabricated and tested independently to ensure optimum filter responses. The proposed filter can be tuned to any frequency between 22 and 24 GHz based on electrostatic actuations. It demonstrates insertion loss of 1.67 dB and matching of 18.6 dB at 24 GHz with fractional bandwidth of 6.5%. Filter gives acceptable matching over a 5 GHz bandwidth (21.65-26.65 GHz) with an average insertion loss of 4.7 dB. Filter works satisfactorily up to 10 billion cycles with 0.1 to 1 W of RF power. To the best of our knowledge, this is the first reported tunable MEMS bandpass filter at 24 GHz with 10 billion cycles reliability and with 1 W of RF power for radar applications. © 2021 Wiley Periodicals LLC.

Frequency and bandwidth tunable reliable MEMS bandpass filter for 24 GHz radar applications

This paper proposes a hybrid decoupling method based on a novel electromagnetic bandgap (EBG) structure and hair-pin shaped defected ground structure (DGS) to obtain high isolation between 2-element multiple input multiple output (MIMO) antenna at 5G millimeter wave band over 27.5-28.35$ GHz. The proposed EBG designed on stacked dielectric substrates, achieves a wide frequency band-gap between 26.2-32.03 GHz (20 %). A 2 × 3 array of the EBG is arranged between two electromagnetically coupled radiating patches in order to suppress the surface wave coupling. Substrate integrated waveguide (SIW) feeding network and cavity are strategically incorporated in the antenna design for improving the radiation performance and minimizing the losses from the feed. EBG shows an average isolation improvement of 13.9 dB within 5G band as compared to unloaded MIMO antenna. The additional reduction in coupling is achieved by placing hair-pin DGS (HP-DGS) on the ground plane, resulting in maximum isolation improvement of 47.7 dB at 27.94 GHz. The prototype of the MIMO was fabricated and experimentally verified. Measured peak isolation between the antennas is obtained as 71.9 dB, having a gain of 9 dBi and front to back ratio (FTBR) of 19.8 dB. A good diversity performance is also noticed for the designed MIMO with envelope correlation coefficient (ECC) of 0.00015, diversity gain (DG) of 9.99, and channel capacity loss (CCL) of 0.025 bits/Hz/sec. Later, SIW corporate feed network is designed for 4-element linear array loaded with EBG and HP-DGS to achieve higher gain and narrow beamwidth. The array was fabricated and the measured results are found in good accordance with the simulation results. The peak gain, beamwidth, and FTBR of the array are 13.3 dBi, 16.2°, and 19.97 dB respectively. © 2021 IEEE.