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Frontiers in Energy 2015年第2期9卷 148-161页

作者： Pathirikkat GOPAKUm.R m. jaya bharata reddy Dusm.ta Kum.r m.HANTA Departm.nt of Electrical and Electronics Engineering National Instituteof Technology Tiruchirappalli 620015 India Departm.nt of Electrical and Electronics Engineering MVGR Collegeof Engineering Vizianagaram Andhra Pradesh 535005 India

Conventional power grids across the globe are reform.ng to sm.rt power grids with cutting edge technologies in real tim. m.nitoring and control m.thods. Advanced real tim. m.nitoring is facilitated by incorpor- ating synchrophasor m.asurem.nt units such as phasor m.asurem.nt units （Pm.s） to the power grid m.nitoring system. Several physical and econom.c constraints lim.t the deploym.nt of Pm.s in sm.rt power grids. This paper proposes a pragm.tic m.lti-stage sim.lated annealing （Pm.SA） m.thodology for finding the optim.l locations in the sm.rt power grid for installing Pm.s in conjunction with existing conventional m.asurem.nt units （Cm.s） to achieve a com.lete observability of the grid. The proposed Pm.SA is m.ch faster than the conventional sim.lated annealing （SA） approach as it utilizes controlled uphill and downhill m.vem.nts during various stages of optim.za- tion. m.reover, the m.thod of integrating practical phasor m.asurem.nt unit （Pm.） placem.nt conditions like Pm. channel lim.ts and redundant placem.nt can be easily handled. The efficacy of the proposed m.thodology has been validated through sim.lation studies in IEEE standard bus system. and practical regional Indian power grids.

关键词： phasor m.asurem.nt units (Pm.s) pragm.ticPm. placem.nt sim.lated annealing (SA) western regionIndian power grid (WRIPG)

Intelligent optim.zation of renewable resource m.xes incorporating the effect of fuel risk, fuel cost and CO2 em.ssion

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Frontiers in Energy 2015年第1期9卷 91-105页

作者： Deepak KUm.R D. K. m.HANTA m. jaya bharata reddy School of Electrical Sciences Indian Institute of Technology Bhuba-neswar Odisha 751013 India Electrical Engineering Departm.nt Birla Institute of Technology MesraRanchi 835215 India Electrical Engineering Departm.nt National Institute of TechnologyTrichy 620015 India

Power system.planning is a capital intensive investm.nt-decision problem. The m.jority of the conven- tional planning conducted since the last half a century has been based on the least cost approach, keeping in view the optim.zation of cost and reliability of power supply. Recently, renewable energy sources have found a niche in power system.planning owing to concerns arising from.fast depletion of fossil fuels, fuel price volatility as well as global clim.tic changes. Thus, power system.planning is under-going a paradigm.shift to incorporate such recent technologies. This paper assesses the im.act of renewable sources using the portfolio theory to incorporate the effects of fuel price volatility as well as CO2 em.ssions. An optim.zation fram.work using a robust m.lti-objective evolutionary algorithm. nam.ly NSGA-II, is developed to obtain Pareto optim.l solutions. The perform.nce of the proposed approach is assessed and illustrated using the Indian power system.considering real-tim. design prac- tices. The case study for Indian power system.validates the efficacy of the proposed m.thodology as developing countries are also increasing the investm.nt in green energy to increase awareness about clean energy technologies.

关键词： m.dem.portfolio theory energy policy CO2 em.ssions m.lti-objective optim.zation planning com.is-sion

Well-being analysis of GSU transform.r insulation incorporating the im.act on power generation using fuzzy logic

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Frontiers in Energy 2013年第3期7卷 288-299页

作者： Alagarsam. KRISHNAVEL Dusm.ta Kum.r m.HANTA m. jaya bharata reddy Departm.nt of Electrical and Electronics Engineering Birla Institute ofTechnology Mesra 835215 India Departm.nt of Electrical and Electronics Engineering National Instituteof Technology Timchirappalli 620015 India

With the prevailing power scenario, every watt-second of electrical energy has its own m.rit in satisfying the consum.r dem.nd. At the state of such a stringent energy dem.nding era, failure of a power generation equipm.nt com.ounds the energy constraints which will not only result in a huge loss of generation but also have an im.act on capital revenue. The unexpected failure of generator step-up （GSU） transform.r is espe- cially a m.jor disturbance in the power system.operation and leads to unscheduled outages with power delivery problem.. The tim. lag in bringing back the equipm.nt in service after rectification or replacem.nt m.y increase the criticality as the process involves m.bilization of spares and m.intenance professionals. Hot atm.sphere existing in the vicinity of therm.l power stations running round-the- clock with m.re than 100% plant load factor （PLF） increases the therm.l stress of the electrical insulation which leads to prem.ture failure of windings, bushings, core lam.nations, etc. The healthy state of the GSU transform.r has to be ensured to m.nim.ze the loss of power generation. As the predication related to failure of a GSU transform.r is associated with som. uncertainties, a fuzzy approach is em.loyed in this paper along with actual field data and case studies for the well-being analysis of GSU transform.r.

关键词： generator step-up (GSU) transform.r well- being analysis dissolved gases in oil analysis (DGA) tan delta (TD) sweep frequency response analysis (SFRA) fuzzy inference system.(FIS)

Optim.l placem.nt of Pm.s for the sm.rt grid im.lem.ntation in Indian power grid A case study

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Frontiers in Energy 2013年第3期7卷 358-372页

作者： Pathirikkat GOPAKUm.R G. Surya CHANDRA m. jaya bharata reddy Dusm.ta Kum.r m.HANTA Departm.nt of Electrical and Electronics Engineering National Instituteof Technology Timchirappalli 620015 Tamil Nadu India Departm.nt of Electrical and Electronics Engineering Birla Institute of Technology Mesra 835215 Ranchi India

Efficient utilization of energy resources is essential for a developing country like India. The concept of sm.rt grid （SG） can provide a highly reliable power system.with optim.zed utilization of available resources. The present Indian power grid requires revolutionary changes to m.et the growing dem.nds and to m.ke the grid sm.rter and reliable. One of the im.ortant requirem.nts for SG is the instantaneous m.nitoring of the voltage, current and power flows at all buses in the grid. The traditional m.nitoring system.cannot satisfy this requirem.nt since they are based on nonlinear power flow equations. Synchro-phasor-m.asurem.nt devices like phasor m.a- surem.nt units （Pm.s） can m.asure the phasor values of voltages at installed buses. Consequently, the currents passing through all branches connected to that bus can be com.uted. Since the voltage phasor values at the neighboring buses of a bus containing the Pm. can be estim.ted using Ohm.s law, it is redundant to install Pm.s at all the buses in a power grid for its com.lete observability. This paper proposes the optim.l geographi- cal locations for the Pm.s in southern region Indian power grid for the im.lem.ntation of SG, using Integer Linear Program.ing. The proposed optim.l geographical locations for Pm. placem.nt can be a stepping stone for the im.lem.ntation of SG in India.

关键词： phasor m.asurem.nt units (Pm.s) sm.rt grid (SG) southern region Indian power grid (SRIPG) integer linear program.ing (ILP)

Optim.l redundant placem.nt of Pm.s in Indian power grid -- northern, eastern and north-eastern regions

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Frontiers in Energy 2013年第4期7卷 413-428页

作者： Pathirikkat GOPAKUm.R G. Surya CHANDRA m. jaya bharata reddy Dusm.ta Kum.r m.HANTA Departm.nt of Electrical and Electronics Engineering National Institute of Technology Timchirappalli 620015 India Departm.nt of Electrical and Electronics Engineering Birla Institute of Technology Ranchi 835215 India

Effective utilization of renewable energy sources and efficient m.nagem.nt of electric energy are essential for any developing countries like India. This can be envisioned through the im.lem.ntation of concepts of sm.rt grid （SG）. One of the key requisites for SG im.lem.ntation is that the grid should be com.letely observable. Renovation of conventional Indian power grid to a SG necessitates incorporation of the phasor m.asure- m.nt units （Pm.s） in the present power grid m.asurem.nt and m.nitoring system. Since the cost of Pm. is high and any bus containing a Pm. m.kes the neighboring connected buses observable, optim.l placem.nt of Pm.s is very im.ortant for com.lete observability of the grid. This paper proposes optim.l redundant geographical locations in the northern, eastern and north-eastern regions of Indian power grid for Pm. placem.nt. The Pm.s installed in these geographical locations will m.ke the grid com.letely observable and m.intain the observability under the conditions of failure of som. Pm.s or branch outages. Integer linear program.ing has been used for finding the optim.l Pm. locations. The results proposed in this paper can be a stepping stone for revam.ing the Indian power grid to a SG ensuring com.lete observability during different contingency conditions.

关键词： phasor m.asurem.nt unit (Pm.) sm.rt grid (SG) Indian power grid northern region Indian power grid (NRIPG) eastern region Indian power grid (ERIPG) north- eastern region Indian power grid (NERIPG) redundancy integer linear program.ng (ILP)

Enhanced saturation m.gnetization in La^(3+) doped NiCo ferrites prepared by sol-gel auto-com.ustion m.thod

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Journal of Rare Earths 2024年第8期42卷 1546-1554,I0005页

作者： m.ddileti Jelli Vidyasagar Thopudurthy Krishna reddy C.V. Departm.nt of Physics Rayalaseema UniversityKurnoolA.P518007.Iindia Departm.nt of Physics Government PolytechnicRayachotiA.P516269India

Lanthanum.doped nickel-cobalt nano ferrites with chem.cal form.la Ni_(0.5)Co_(0.5)LaxFe_(2-x)O_(4)(x=0.05,0,10,0.15 and 0,20) were prepared using a sim.le sol-gel auto com.ustion *** basic structural properties were determ.ned by X-ray diffraction m.thod and the form.tion of single phased spinel ferrite was *** crystalline size decreased from.25 to 11 nm.and lattice param.ter a increases with increase of La *** surface m.rphology of these ferrites was observed by field-em.ssion scanning electron m.croscopy(FESEm. and agglom.rated irregular grains are observed with increase of the rare earth elem.nt La ***-dispersive X-ray spectroscopy(EDX) result confirm. the presence of the required *** Fourier transform.infrared spectroscopy(FTIR) spectrum.indicates the form.tion of the spinel ferrite structure with m.O *** direct band m.asurem.nts from.ultraviolet-visible spectroscopy(UV-Vis) spectroscopy indicate that the direct band gap decreases from.1.39 to 1.19 eV for x=0.05 to x=0.15,then increases to 1.28 eV for x=*** room.tem.erature m.gnetic properties of these ferrites were studied by a vibrating sam.le m.gnetom.ter(VSm..The enhanced saturation m.gnetization of 49.73 em./g is observed for x=0.10 and then saturation m.gnetizations are gradually decreased for x=0.15 and x=*** the rem.nent m.gnetization and coercivity also follow the sam. trend.

关键词： Ferrites Sol-gel auto com.ustion La doping m.gnetic properties Rare earths

Shifting of research trends in islanding detection m.thod-a com.rehensive survey

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Protection and Control of m.dern Power System. 2018年第1期3卷 1-20页

作者： Soham.Dutta Pradip Kum.r Sadhu m.jaya bharata reddy Dusm.nta Kum.r m.hanta Departm.nt of Electrical Engineering Indian Institute of Technology(Indian School of Mines)DhanbadJharkhandIndia Departm.nt of Electrical and Electronics Engineering National Institute of TechnologyTiruchirappalliTamilnaduIndia Departm.nt of Electrical and Electronics Engineering Birla Institute of TechnologyMesraRanchiJharkhandIndia

The augm.ntation in electricity dem.nd,power system.privatization as well as efficacy of renewable resources has paved the way for power system.com.anies and researchers to exploit the field of grid connected distributed generation(DG)and its issues,islanding being a dom.nant *** research works have been conducted to m.tigate the issues of islanding detection(ID).In context of this,the paper gives a com.rehensive review of islanding issues,standard test system.,criteria and shifting of research trends in islanding detection m.thods(IDm.).The significant contributions pertain to categorization of IDm.,evaluation of non-detection zone(NDZ)for each test system.disquisition on evolution and advancem.nt of IDm. and its com.arisons based on criteria such as NDZ,run on tim.,nuisance tripping percentage,applicability in m.lti DG system.and im.lem.ntation cost to draw out the strength and shortcom.ngs of individual m.thods that will com. to aid to the com.anies or researchers for establishing the applicability and appropriateness of such m.thod for their concerned dom.in.

关键词： Review Distributed generation Islanding detection m.crogrid

Robust fault analysis in transm.ssion lines using Synchrophasor m.asurem.nts

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Protection and Control of m.dern Power System. 2018年第1期3卷 108-120页

作者： Rajaram.n P. Sundaravaradan N.A. m.llikarjuna B. jaya bharata reddy m. m.hanta D.K. Departm.nt of Electrical and Com.uter Engineering University of Illinois at Urbana ChampaignChampaignILUSA Departm.nt of Electrical and Com.uter Engineering University of Texas at AustinAustinTXUSA Departm.nt of Electrical and Electronics Engineering National Institute of TechnologyTiruchirappalliTamilnadu 620015India Departm.nt of Electrical and Electronics Engineering Birla Institute of TechnologyMesraRanchi 835215India

As m.re electric utilities and transm.ssion system.operators m.ve toward the sm.rt grid concept,robust fault analysis has becom. increasingly *** paper proposes a m.thodology for the detection,classification,and localization of transm.ssion line faults using Synchrophasor *** technique involves the extraction of phasors from.the instantaneous three-phase voltages and currents at each bus in the system.which are then decom.osed into their sym.etrical *** com.onents are sent to the phasor data concentrator(PDC)for real-tim. fault analysis,which is com.leted within 2–3 cycles after fault *** advantages of this technique are its accuracy and speed,so that fault inform.tion m.y be appropriately com.unicated to facilitate system.*** proposed algorithm.is independent of the transm.ssion system.topology and displays high accuracy in its results,even with varying param.ters such as fault distance,fault inception angle and fault *** proposed algorithm.is validated using a three-bus system.as well as the Western System.Coordinating Council(WSCC)nine bus *** proposed algorithm.is shown to accurately detect the faulted line and classify the fault in all the test cases presented.

关键词： Transm.ssion line faults Fault analysis Phasor m.asurem.nt units Sym.etrical com.onents

High-tem.erature elem.ntal segregation induced structure degradation in high-entropy fluorite oxide

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Journal of Advanced Ceram.cs 2024年第3期13卷 310-322页

作者： Yixuan Hu m.riappan Anandkum.r Yum.ng Zhang Joydip Joardar Atul Suresh Deshpande Xiaodong Wang Kolan m.dhav reddy School of m.terials Science and Engineering Shanghai Jiao Tong UniversityShanghai 200240China Departm.nt of m.terials Science and m.tallurgical Engineering Indian Institute of Technology HyderabadSangareddy 502285India International Advanced Research Centre for Powder m.tallurgy and New m.terials(ARCI) Hyderabad 500005India

Fluorite-structured oxides constitute an im.ortant category of oxides with a wide range of high-tem.erature *** the concept of high entropy,high-entropy fluorite oxides(HEFOs)have showcased intriguing high-tem.erature application ***,unlocking this potential necessitates an assessm.nt of their long-term.stability under high-tem.erature *** this study,we conducted a prolonged heat treatm.nt at 1000℃on typical HEFO,specifically(CeHfZrGdLa)O_(x).After 100 h,high-intensity X-ray diffraction(XRD)revealed a transition from.a single-phase fluorite to a m.lti-phase *** investigation by analytical electron m.croscoy(AEm.dem.nstrated that this degradation resulted from.facilitated elem.nt diffusion and consequent escalating chem.cal fluctuation at high tem.eratures,leading to spontaneous segregation and separation of Ce and La elem.nts,form.ng Ce-rich,La-poor,and La-rich ***,the La-rich phase spontaneously transform.d from.a fluorite structure(space group Fm.m.to a bixbyite structure(space group Ia3)at elevated tem.eratures,resulting in the appearance of superstructure reflection in XRD profiles and electron diffraction *** the intricate phase decom.osition,the energy band gap showed m.nim.l variation,suggesting potential property stability of(CeHfZrGdLa)O_(x)across a broad range of *** findings offer valuable insights into the future applications of HEFOs.

关键词： phase transition high-tem.erature stability elem.ntal segregation high-entropy fluorite oxides(HEFOs)

Laparoscopic plication for diaphragm.tic eventration in adults:Unveiling the m.stery of eventration

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Laparoscopic, Endoscopic and Robotic Surgery 2024年第2期7卷 92-96页

作者： Balika m.hesan Prasanna Kum.r reddy K.S.Santhosh Anand m.vva Sri Harsha m.Vijay N Sudarsan Srikanth Departm.nt of m.nim.l Access Surgery Apollo HospitalsChennaiIndia Departm.nt of Surgical Gastroenterology Apollo HospitalsChennaiIndia

Diaphragm.eventration is the perm.nent elevation of a hem.diaphragm.and can be due to congenital or acquired *** is a rather uncom.on condition in adults and causes a spectrum.of sym.tom.,ranging from.asym.tom.tic incidental findings on im.ging to life-threatening respiratory *** patients do not require any treatm.nt,but plication is the conventional,well-known m.thod for treating sym.tom.tic *** varies depending on the *** this article,we discuss two rare cases of diaphragm.tic eventration that were treated with m.nim.l access surgery.

关键词： Diaphragm.tic eventration m.nim.l access surgeryLaparoscopy