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Search Results: 1 - 10 of 462167 matches for " A. Jaya Laxmi "
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Role of PI and fuzzy controllers in unified power quality conditioner
A. Jaya Laxmi,G. Tulasi Ram Das,K. Uma Rao
Journal of Engineering and Applied Sciences , 2007,
Abstract: Any electrical power system consists of wide range of electrical, electronic and power electronic equipment in commercial and industrial applications. Since most of the electronic equipment is nonlinear in nature these will induce harmonics in the system, which affect the sensitive loads to be fed from the system. One among the many compensating devices is Unified Power Quality Conditioner (UPQC) which specifically aims at the integration of series-active and shunt-active power filters to mitigate any type of voltage and current fluctuations and power factor correction in a power distribution network, such that improved power quality can be made available at the point of common coupling. The present work discusses the compensation principle and different control strategies (PI, FUZZY) of the UPQC in detail. The control strategies are modeled using MATLAB/SIMULINK. The performance of UPQC is examined by considering, a thyristor rectifier feeding an RL load (non linear load) that acts as a source of harmonics, to the system of concern. The performance is also observed under influence of utility side disturbances such as sag, swell, flicker and spikes. The simulation results are listed in comparison of different control strategies and for the verification of results.
Detection of high-impedance faults in transmission lines using Wavelet Transforms
M. Sushama,G. Tulasi Ram Das,A. Jaya Laxmi
Journal of Engineering and Applied Sciences , 2009,
Abstract: A novel approach for detection of High Impedance Faults (HIF) using wavelet transforms is presented in this work. Wavelet functions have been proposed in connection with the analysis of signals, primarily transients in a wide range of applications. The technique used here, is based on using the absolute sum value of coefficients in Multi resolution Signal Decomposition (MSD) based on the Discrete Wavelet Transform (DWT). A fault indicator and a fault criterion are then used to detect the HIF in the transmission line. The technique developed is robust to fault type, fault inception angle, fault resistance, and fault location. A new concept and methodology for HIF in transmission lines is presented. The performance of the proposed technique is tested under a variety of fault conditions on a typical 400KV transmission-line system.
MODELING AND CONTROL OF HYBRID PHOTOVOLTAIC-WIND ENERGY CONVERSION SYSTEM
Yerra Sreenivasa Rao,A. Jaya Laxmi,Mostafa Kazeminehad
International Journal of Advances in Engineering and Technology , 2012,
Abstract: This paper proposes a hybrid energy conversion system combing photovoltaic and wind turbine as a small-scale alternative source of electrical energy where conventional generation is not practical. The hybrid system consists of photovoltaic panels, wind turbines and storage batteries. The wind and PV are used as main energy sources, while the battery is used as back-up energy source. Two individual DC-DC boost converters are used to control the power flow to the load. A simple and cost effective control with DC-DC converter is used for maximum power point tracking (MPPT) and hence maximum power is extracted from the o turbine and the photo voltaic array. The modeling of hybrid system is developed in MATLAB- SIMULINK.
MODULATION AND CONTROL TECHNIQUES OF MATRIX CONVERTER
M. Rameshkumar,Y. Sreenivasa Rao,A. Jaya laxmi
International Journal of Advances in Engineering and Technology , 2012,
Abstract: The Matrix converter is a forced commutated Cyclo-converter with an array of controlled semi conductor switches that connects directly the three phase source to the three phase load. The matrix converter is a direct AC-AC Converter. It has no limit on output frequency due to the fact that it uses semiconductor switches with controlled turn-off capability. The simultaneous commutation of controlled bidirectional switches limits the practical implementation and negatively affected the interest in matrix converters. This major problem has been solved with the development of several multi-step commutation strategies that allow safe operation of the switches Examples of these semiconductor switches include the IGBT, MOSFET, and MCT. Some of the modulation techniques existing are Basic, Alesina-Venturi and Space vector Modulation Techniques. Out of the above modulation techniques Space vector Modulation Technique is most widely used. The simulation of matrix converter modulation and control strategies of Space vector Modulation Technique is done by using MATLAB-Simulink.
Reliability Improvement of Distribution System: A Hybrid Approach Based on GA and NN
S.Chandrashekhar Reddy,P.V.N. Prasad,A.Jaya Laxmi
International Journal of Soft Computing & Engineering , 2013,
Abstract: Due to high power demand, modern utilities are continuously planning the expansion of the electrical networks. One of the methods used for the expansion of electrical networks is connecting distributed generator (DG) in the distribution system. The main function of DG is to generate power based on the load condition or any fault occurs in the electrical network. By connecting DG in the distribution system, the power demand of the system can be satisfied and also it improves the reliability of the electrical network. The major problem in DG is, identifying the optimal location for fixing DG in the system and also computing the optimal number of DG to be connected in the system. By considering the abovementioned problem, here a hybrid technique is proposed, which includes genetic algorithm and neural network to identify the optimal number & location of DG to be connected in the system. The proposed method also computes the amount of power to be generated by each DG for various load conditions. By connecting DGs, the number of generators in the network increases and so that different generator states are possible for a particular load condition. From the possible generator states, the best state is selected based on some reliability parameters. Here, the reliability parameters that are considered for identifying the best generator states are loss of load probability (LOLP), loss of load expectation (LOLE), expected energy not supplied (EENS) and system expected outage cost (ECOST). The above reliability parameters are computed for different load conditions and also for the optimal number of DG identified using the proposed method. By using this method, the best generator state for different load conditions and also for different number of generators is computed. The result obtained shows the development in system reliability due to connecting optimal number of DG in the system.
Bidding Strategy in Deregulated Power Market Using Differential Evolution Algorithm  [PDF]
Veera Venkata Sudhakar Angatha, Karri Chandram, Askani Jaya Laxmi
Journal of Power and Energy Engineering (JPEE) , 2015, DOI: 10.4236/jpee.2015.311004
Abstract:

The primary objective of this research article is to introduce Differential Evolution (DE) algorithm for solving bidding strategy in deregulated power market. Suppliers (GENCOs) and consumers (DISCOs) participate in the bidding process in order to maximize the profit of suppliers and benefits of the consumers. Each supplier bids strategically by choosing the bidding coefficients to counter the competitors bidding strategy. Electricity or electric power is traded through bidding in the power exchange. GENCOs sell energy to power exchange and in turn ancillary services to Independent System Operator (ISO). In this paper, Differential Evolution algorithm is proposed for solving bidding strategy problem in operation of power system under deregulated environment. An IEEE 30 bus system with six generators and two large consumers is employed to demonstrate the proposed technique. The results show the adaptability of the proposed method compared with Particle Swarm Optimization (PSO), Genetic Algorithm (GA) and Monte Carlo simulation in terms of Market Clearing Price (MCP).

GSTP: Geographic Secured Two Phase Routing Using MD5 Algorithm  [PDF]
B. Prathusha Laxmi, A. Chilambuchelvan
Circuits and Systems (CS) , 2016, DOI: 10.4236/cs.2016.78159
Abstract: Secured Two Phase Geographic Greedy Forwarding (SecuTPGF) is a geographic greedy forwarding?protocol for transmitting multimedia data stream in Wireless Multimedia Sensor Networks?(WMSN) in a secure and reliable manner. Cryptographic and MAC authentication mechanisms are used to implement security for both node and message authentication. In this paper, a modified?version of SecuTPGF, the GSTP routing provides security for both node and message authentication by using MD5 algorithm with a reduced computation power. In SecuTPGF, two different algorithms are used for node and message authentication, and GSTP routing uses “MD5Algorithm” for both node and message authentication. Using MD5 algorithm for node and message authentication, the average number of transmission paths increased and average number of hops used for transmission decreased when compared to the?SecuTPGF. By conducting security analysis & evaluation experiments, the effectiveness of GSTP routing algorithm is proved.
Rock Mass Rating and Geological Strength Index of rock masses of Thopal-Malekhu River areas, Central Nepal Lesser Himalaya
Jaya Laxmi Singh,Naresh Kazi Tamrakar
Bulletin of the Department of Geology , 2013, DOI: 10.3126/bdg.v16i0.8882
Abstract: The rock slopes of the Thopal-Malekhu River areas, Lesser Himalaya, were characterized applying various systems of rock mass classification, such as Rock mass Rating (RMR) and Geological Strength Index (GSI), because the study area comprises well exposed rock formations of the Nawakot and Kathmandu Complexes, across the Thopal-Malekhu River areas. In RMR system, mainly five parameters viz. Uniaxial Compressive Strength (UCS) of rock, Rock Quality Designation (RQD), spacing of discontinuity, condition of discontinuity, and groundwater condition were considered. The new GSI charts, which were suitable for schistose and much disintegrated rock masses, were used to characterize rock slopes based on quantitative analysis of the rock mass structure and surface condition of discontinuities. RMR ranged from 36 to 82 (poor to very good rock mass) and GSI from 13.5±3 to 58±3 (poor to good rock mass). Slates (of the Benighat Slate) are poor rock masses with low strength, very poor RQD, and close to very close spacing of discontinuity, and dolomites (Dhading Dolomite) are fair rocks with disintegrated, poorly interlocked, and heavily broken rock masses yielding very low RMR and GSI values. Phyllites (Dandagaun Phyllite), schist (Robang Formation) and quartzite (Fagfog Quartzite, Robang Formation and Chisapani Quartzite), dolomite (Malekhu Limestone), and metasandstone (Tistung Formation) are fair rock masses with moderate GSI and RMR values, whereas quartzose schist and gneiss (Kulekhani Formation) are very good rock masses having comparatively higher RMR and GSI. The relationship between GSI and RMR shows positive and good degree of correlation. DOI: http://dx.doi.org/10.3126/bdg.v16i0.8882 ? Bulletin of the Department of Geology Vol. 16, 2013, pp. 29-42
Toppling and wedge failures in Malekhu River area, Malekhu, Central Nepal Lesser Himalaya
Naresh Kazi Tamrakar,Jaya Laxmi Singh,Krishna Kumar Bista,Prayag Maharjan
Bulletin of the Department of Geology , 2013, DOI: 10.3126/bdg.v16i0.8881
Abstract: A huge landslide was identified on the right bank of the Malekhu River at about 1 km upstream from the Malekhu Bridge of the Prithvi Highway, and was named Malekhu Landslide. The landslide area consists of quartzite with sericite partings, chlorite schist and amphibolite of the Robang Formation of the Kathmandu Complex. The landslide extends for about 200 m along the river bank slope and its crown and toe have elevation respectively of 429 m and 361 m a.s.l. The major portion of the hillslope has been altered by landsliding as evidenced from the different geometry of slopes consisting of very steep scarp slope, steep to moderate slope with toppled and wedge failure debris, and several wedges and gullies. The right-side up layers have an average dip direction of 167° and a plunge of 56-90°, whereas the overturned layers have an average dip direction and plunge of 316°/32°. The direction towards which the toppling had occurred is 167°. The overturned layers had rotated to 36°, during which the layer dip direction had rotated counterclockwise to an amount of 31° from the major direction of toppling, and this rotation should have occurred during sliding of the toppled block. The Malekhu Landslide is a complex landslide experiencing more than one mode of failure of which the most prominent one is the toppling. It is a kind of flexural toppling of passive mode and had already occurred and now is suspended. The second mode of failure is the wedge sliding. The kinematic analysis of discontinuities on the slope for evaluating possibility of landsliding has indicated that the wedge failure is potential due to the presence of a line of intersection produced by the discontinuity parallel to the foliation of the right-side up layers and the overturned layers. This suggests that the toppled blocks may further slide. It is required to protect the slope from landsliding as there have been extended two unpaved roads one along the crown and the other along the toe of the landslide, and due to existence of the Malekhu Bridge in the downstream stretch of the river. DOI: http://dx.doi.org/10.3126/bdg.v16i0.8881 Bulletin of the Department of Geology Vol. 16, 2013, pp. 21-28
Optimized and Secured Educlouds by Implementing Virtualization
R. Rajesh,A. Jaya Lakshmi
International Journal of Electronics and Computer Science Engineering , 2012,
Abstract: Cloud computing is an emerging technology that access remote servers through Internet to maintain data and applications. It incorporates the advantages of grid and utility computing. Academia has not remained unaware of this trend, and several educational solutions(LMS) based on cloud technologies are already in place, especially for software as a service(SAAS) cloud. Education is a self-enlightening process. All the country spends huge amount for education from primary to higher education either directly or indirectly. Cloud computing is a correct choice for providing flexibility for all educational institutions. In this paper, we expresses the importance of cloud computing, guidelines to develop cloud computing for education are provided and various security crisis related to data management. It also includes various tools for developing cloud computing and virtualization of resources that maintains and manages itself
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