Faculty Publications
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Item A sensitivity matrix-based temperature-augmented probabilistic load flow study(Institute of Electrical and Electronics Engineers Inc., 2017) Prusty, B.R.; Jena, D.This paper proposes a hybridmethod for probabilistic load flow (PLF) study to analyze the influence of uncertain photovoltaic generations and load demands on transmission system performance. Besides, the paper focuses on accurate approximation of multimodal distributions of result variables in a temperatureaugmented PLF model without using any series expansion methods. The effect of uncertain ambient temperature on result variables is discussed. Multiple correlation cases between the input bus powers are considered. The performance of the proposed method is investigated on modified New England 39-bus power system. The results are compared with four well-established analyticalmethods and Monte Carlo simulation. The effect of multiple input correlations on probability distributions of result variables is analyzed. © 2017 IEEE.Item Cumulant-based correlated probabilistic load flow considering photovoltaic generation and electric vehicle charging demand(Higher Education Press Limited Company, 2017) Bhat, N.G.; Prusty, B.R.; Jena, D.This paper applies a cumulant-based analytical method for probabilistic load flow (PLF) assessment in transmission and distribution systems. The uncertainties pertaining to photovoltaic generations and aggregate bus load powers are probabilistically modeled in the case of transmission systems. In the case of distribution systems, the uncertainties pertaining to plug-in hybrid electric vehicle and battery electric vehicle charging demands in residential community as well as charging stations are probabilistically modeled. The probability distributions of the result variables (bus voltages and branch power flows) pertaining to these inputs are accurately established. The multiple input correlation cases are incorporated. Simultaneously, the performance of the proposed method is demonstrated on a modified Ward-Hale 6-bus system and an IEEE 14-bus transmission system as well as on a modified IEEE 69-bus radial and an IEEE 33-bus mesh distribution system. The results of the proposed method are compared with that of Monte-Carlo simulation. © 2017, Higher Education Press and Springer-Verlag Berlin Heidelberg.Item Electric Field Reduction in an EHV Substation for Occupational Exposure via Transposition of Conductors(Institute of Electrical and Electronics Engineers Inc., 2018) Devarajan, D.; Punekar, G.S.An attempt is made to reduce the maximum value of rms electric field (E-field) via the transposition of conductors in a 765-kV substation with reference to the occupational exposure. The method is applied to a extra-high-voltage substation, which is under construction. The effect of transposing the bay conductors (alone) and the bus conductors (alone) on the E-field distribution (at 2 m above the ground) over the area of the substation is discussed. Also, the topology of substation conductors that results in the minimum value for the maximum of rms E-fields is obtained via simultaneous transpositions of the bus and bay conductors. The area of the substation where the rms E-field exceeds the reference value of 10 kV/m (International Commission on Non-Ionizing Radiation Protection occupational exposure limit) is also reported for the existing topology. For this topology, the computed maximum value of the rms E-field over the area of the substation is 13.06 kV/m. This E-field is reduced to 7.999 kV/m with the best configuration of substation conductors obtained via transposition. The charge-simulation-method-based generalized algorithm for obtaining the best topology (among all permutations) of substation conductors, which results in the minimum value for the maximum of rms E-field magnitudes over the substation area is also reported. © 1986-2012 IEEE.Item A spatiotemporal probabilistic model-based temperature-augmented probabilistic load flow considering PV generations(John Wiley and Sons Ltd vgorayska@wiley.com Southern Gate Chichester, West Sussex PO19 8SQ, 2019) Prusty, B.R.; Jena, D.The probabilistic steady-state forecasting of a PV-integrated power system requires a suitable forecasting model capable of accurately characterizing the uncertainties and correlations among multivariate inputs. The critical and foremost difficulties in the development of such a model include the accurate representation of the characterizing features such as complex nonstationary pattern, non-Gaussianity, and spatial and temporal correlations. This paper aims at developing an improved high-dimensional multivariate spatiotemporal model through enhanced preprocessing, transformation techniques, principal component analysis, and a suitable time series model that is capable of accurately modeling the trend in the variance of uncertain inputs. The proposed model is applied to the probabilistic load flow carried out on the modified Indian utility 62-bus transmission system using temperature-augmented system model for an operational planning study. A detailed discussion of various results has indicated the effectiveness of the proposed model in capturing the aforesaid characterizing features of uncertain inputs. © 2019 John Wiley & Sons, Ltd.Item Modelling of OFDM based RoFSO system for 5G applications over varying weather conditions: A case study(Elsevier GmbH, 2019) Pati, P.S.; Krishnan, P.From the perspective of spectrum scarcity, Radio-on-FSO (RoFSO)system is the best available option as it operates at unlicensed optical frequencies with the salient features of high bandwidth, cost effectiveness, lower transmit power, immunity to electromagnetic interference and easy deployment. To cater to the high data rate requirement of 5G applications in the near future, RoFSO systems will definitely be the best assisted alternative technology to the conventional wireless systems. However, the atmospheric conditions and non-linearity of the optical link have got a bearing on the efficiency of the system. In this work, we have presented an analytical model for transmitting phase shift keying (PSK)modulated orthogonal frequency division multiplexing (OFDM)signals through free space optics (FSO)links. RL is the load resistor of the photo detector an Considering optical noises, nonlinear distortion resulting from laser diode and the atmospheric turbulence effect modelled by gamma-gamma distribution, we have derived a closed form closed-form bit error rate (BER)and outage probability expression for the aforementioned transmission system. Pointing error is also factored in for more accurate and appropriate analysis of the system performance. Better system performance was observed through use of aperture averaging technique. A case study has been undertaken for analyzing the FSO system performance with reference to BER for various seasons for the year 2016 over IIIT Bhubaneswar area by considering the wind speed and altitude at different floors of the building of the institute. © 2019 Elsevier GmbHItem A 8–12 GHz, 44.3 dBm RF output class FF?1 DPA using quad-mode coupled technique for new configurable front-end 5G transmitters(Springer, 2021) Kumar, R.; Dwari, S.; Kumar Kanaujia, B.K.; Kumar, S.; Song, H.This paper presents a high-efficiency Class FF - 1 DPA using the quad-mode coupled technique for new configurable front-end 5G transmitters. The proposed DPA consists of carrier PA, main PA, input–output matching network and hybrid power network (HPN). The HPN includes a quad-mode coupled technique which is four-section U-shaped transmission line. The HPN is used for even–odd mode impedance analysis to ensures the high-selectivity of output power and achieve a wideband response in the presence of harmonic control conditions. The optimum harmonic impedance is analyzed for the desired band to achieve high output power and efficiency. The DPA circuit is fabricated by using 0.25 µm GaN HEMT on silicon nitride monolithic microwave integrated circuit die process. At maximum output power level of 44.3 dBm, the delivered power-added efficiency (PAE) of 64.3–67.3% and drain efficiency (DE) of 71.7–73.7% at even–odd mode operation are achieved with a gain of 13.0–14.3 dB. For the output power level of 39.045 dBm corresponding to 9 dB output back-off (OBO), the drain efficiency lies between 55–62% with 73% fractional bandwidth. All the demonstrated transmission parameters are working in the band of 8–12 GHz. The size of the chip is 2.8 × 1.9 mm2 and it occupies less die area as compared to the existing DPAs. © 2021, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.Item Investigations of redox-active polyoxomolybdate embedded polyaniline-based electrode material for energy application(Springer Science and Business Media Deutschland GmbH, 2022) Anandan Vannathan, A.A.; Kella, T.; Shee, D.; Mal, S.S.Higher capacitance supercapacitors have received considerable attention, including their massive power density, high stability, and long cycle life. On the other hand, polymers have been known for their energy storage device application because of the pseudocapacitance behavior resulting from the extended conjugation over the polymer backbone. Here, we report a simple chemical bath deposition method for the synthesis of two polyoxometalates (H4[PVMo11O40] and H5[PV2Mo10O40]) impregnated polyaniline (PAni) composite (PVMo11@PAni and PV2Mo10@PAni) for electrochemical supercapacitors. Various analytical methods characterized the electrode materials, e.g., Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), powder X-ray diffraction (PXRD) method, and the morphological features of those electrodes were acquired by field emission scanning microscopy (FESEM). The exceptionally high average capacitance of 1371 F g−1 was obtained for the composite PVMo11@PAni electrode at a 3 A g−1 current density and 1 V potential window with an energy density of 137.5 W h kg−1. The PVMo11@PAni composite electrode showed almost 4.3 times the higher energy density than pure PAni and 2.3 times higher than PV2Mo10@PAni. In contrast, PV2Mo10@PAni composite showed 1.9 times more energy density than pure PAni composite electrode. Interestingly, high average capacitance, charge–discharge rates, and high energy density with high-level power delivery make them promising electrode candidates for supercapacitors. © 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.Item Power system event detection and localization—A new approach(Elsevier Ltd, 2023) Aalam, M.K.; Shubhanga, K.N.Time-synchronized estimates acquired using the Wide Area Measurement System (WAMS) have substantially helped enhance the health of the modern power grid. WAMS data when used in conjunction with appropriate tools can aid in the timely detection of power system events. With the continuous expansion of the WAMS network, identification of events and narrowing down on their location is emerging as a serious challenge for power system operators. Therefore, in this paper an event detection and localization tool is developed which analyzes data obtained from multiple Phasor Measurement Units (PMUs) installed throughout the WAMS network in order to identify the occurrence of an event. The effectiveness of this tool is demonstrated using practical signals from the ISO-NE power system and simulation based signals obtained from a 4-machine 10-bus system. Occurrence of an event is flagged by comparing the wavelet energy and standard deviation values of a PMU signal against a threshold. An event localization algorithm based on the number of PMUs involved in the event detection stage is proposed. Based on the presented algorithm, disturbances are classified as local or wide-spread events. Finally, a method to identify a loss-of-synchronism condition using phase angle difference (PAD) signals obtained across transmission lines is also proposed. © 2023 Elsevier B.V.Item Comparative Analysis of 500 kV Double-Circuit Transmission Line Electric Field Intensity: Ethiopian Lines Compliance With ICNIRP(Institute of Electrical and Electronics Engineers Inc., 2024) Tefera, T.N.; Punekar, G.S.; Ibrahim Yassin, K.; Tuka, M.The high-intensity electric fields, which are in the vicinity of power transmission lines, have adverse effects on human and other living beings if they are not within the specified limits. The International Commission on Non-ionizing Radiation Protection (INCIRP) specifies guidelines for these E-fields from the perspective of public exposure at the ground level and sets it to 5 kV/m at 50 Hz. Thus, this study was aimed at analyzing and comparing the E-fields intensity of differently configured double-circuit 500 kV transmission lines at a height of 1 m above the ground plane. Charge Simulation Method (CSM) using MATLAB as a programming platform is used for this study. Among the tower configurations studied, a configuration that provided minimum E-fields with minimum ground clearance was identified. From the actual built transmission lines included in the study, vertical lines configuration produces a minimum E-fields intensity of 4.565 kV/m root mean square and fulfills the INCIRP requirement. However, triangular line configuration is the preferable configuration for 500 kV double circuit transmission lines giving the least E-fields at the ground with minimum ground clearance using optimized phase sequence arrangements irrespective of other comparative parameters. Additionally, an evaluation of these line configurations based on the distribution of the conductor surface E-fields was conducted. The study reveals that the E-fields on the surface of the transmission line conductors included in the study remains significantly below the intrinsic breakdown strength of atmospheric air. Therefore, it was anticipated that the designs will remain free from corona discharge under fair weather conditions. © 2013 IEEE.Item Hydrodynamic performance of hybrid floating breakwater integrated with oscillating water column(SAGE Publications Ltd, 2025) Vishwakarma, R.D.; Karmakar, D.The present study investigates the hydrodynamic performance of different types of hybrid floating breakwaters (HFB) integrated with an oscillating water column (OWC). The study is performed for five different cross-sectional shapes of HFB, such as rectangular, box, H, ?, and trapezoidal, with the inclusion of OWC of the same dimension in all of the hybrid floating breakwaters. The performance of the HFBs is examined for its motion response, wave transmission coefficient, and power capture under the action of the regular waves, considering the incident wave normal to the structure. The motion response and wave transmission characteristics assessment are based on potential flow theory, and the power capture due to the HFB is assessed using the volume of fluid (VOF) flow computation method. The HFB model performing better in terms of transmission coefficient and power capture considering wider bandwidth for the considered surface gravity wave frequencies is selected to investigate the effect of changes in HFB’s parameters, such as length, width, draft, and wave incident angle on the hydrodynamic performance. Additionally, the streamline contours for the air flow velocity variation through the OWC chamber in different types of hybrid floating structures are analysed for better understanding of flow through visualisation. The aforementioned streamline contour is determined for the wave frequency where the maximum wave energy capture in the HFB models is observed. The study will facilitate the researchers to comprehensively investigate the stability of hybrid floating breakwater under the influence of regular waves with the help of the findings of the present investigation. © IMechE 2025