International Journal of Advances in Engineering & Technology, Jan 2012.©IJAET                                            ...
International Journal of Advances in Engineering & Technology, Jan 2012.©IJAET                                            ...
International Journal of Advances in Engineering & Technology, Jan 2012.©IJAET                                            ...
International Journal of Advances in Engineering & Technology, Jan 2012.©IJAET                                            ...
International Journal of Advances in Engineering & Technology, Jan 2012.©IJAET                                            ...
International Journal of Advances in Engineering & Technology, Jan 2012.©IJAET                                            ...
International Journal of Advances in Engineering & Technology, Jan 2012.©IJAET                                            ...
International Journal of Advances in Engineering & Technology, Jan 2012.©IJAET                                            ...
International Journal of Advances in Engineering & Technology, Jan 2012.©IJAET                                            ...
International Journal of Advances in Engineering & Technology, Jan 2012.©IJAET                                            ...
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IMPACT OF VOLTAGE REGULATORS IN UNBALANCED RADIAL DISTRIBUTION SYSTEMS USING PARTICLE SWARM OPTIMIZATION Copyright IJAET

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In rural power systems, the Automatic Voltage Regulators (AVRs) help to reduce energy loss and to improve the power quality of electric utilities, compensating the voltage drops through distribution lines. This paper presents selection of optimal location and selection of tap setting for voltage regulators in Unbalanced Radial Distribution Systems (URDS). PSO is used for selecting the voltage regulator tap position in an unbalanced radial distribution system. An algorithm makes the initial selection, installation and tap position setting of the voltage regulators to provide a good voltage profile and to minimize power loss along the distribution network. The effectiveness of the proposed method is illustrated on a test system of 25 bus unbalanced radial distribution systems.

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IMPACT OF VOLTAGE REGULATORS IN UNBALANCED RADIAL DISTRIBUTION SYSTEMS USING PARTICLE SWARM OPTIMIZATION Copyright IJAET

  1. 1. International Journal of Advances in Engineering & Technology, Jan 2012.©IJAET ISSN: 2231-1963 IMPACT OF VOLTAGE REGULATORS IN UNBALANCED RADIAL DISTRIBUTION SYSTEMS USING PARTICLE SWARM OPTIMIZATION Puthireddy Umapathi Reddy1*, Sirigiri Sivanagaraju2, Prabandhamkam Sangameswararaju3 1 Department of Electrical and Electronics Engineering, Sree Vidyanikethan Engineering College, Tirupati, India. 2 Department of Electrical and Electronics Engineering, Jawaharlal Nehru Technological University College of Engineering Kakinada, Kakinada, India.3 Department of Electrical and Electronics Engineering, Sri Venkateswara University College of Engineering, Tirupati, India.ABSTRACTIn rural power systems, the Automatic Voltage Regulators (AVRs) help to reduce energy loss and to improve thepower quality of electric utilities, compensating the voltage drops through distribution lines. This paperpresents selection of optimal location and selection of tap setting for voltage regulators in Unbalanced RadialDistribution Systems (URDS). PSO is used for selecting the voltage regulator tap position in an unbalancedradial distribution system. An algorithm makes the initial selection, installation and tap position setting of thevoltage regulators to provide a good voltage profile and to minimize power loss along the distribution network.The effectiveness of the proposed method is illustrated on a test system of 25 bus unbalanced radial distributionsystems.KEYWORDS: Unbalanced radial distribution systems, Voltage regulator placement, Loss minimization,Particle swarm optimization. I. INTRODUCTIONThis paper describes a new approach for modelling of automatic voltage regulator in theforward/backward sweep-based algorithms for unbalanced radial distribution systems [1], [2]. Avoltage regulator is a device that keeps a predetermined voltage in a distribution network despite ofthe load variations within its rated power [3],[4]. Since it is the utilities’ responsibility to keep thecustomer voltage with in specified tolerances, voltage regulation is an important subject in electricaldistribution engineering [5]. However, most equipment and appliances operate satisfactorily oversome ‘reasonable’ range of voltages; hence, certain tolerances are allowed at the customers’ end.Thus, it is common practice among utilities to stay within preferred voltage levels and ranges ofvariations for satisfactory operation of apparatus as set by various standards [6]. In distributionsystems operation, shunt capacitor banks and feeder regulators are necessary for providing acceptablevoltage profiles to all end-use customers and reducing power losses on large distribution systems [9].A voltage regulator is equipped with controls and accessories for its tap to be adjusted automaticallyunder load conditions. Moreover, it can be controlled by the installation of devices such as fixed andcontrolled capacitors banks, transformers with On Load Tap Changers (OLTCs), and AutomaticVoltage Regulators (AVRs) [11], [12]. Loss reduction and improvement of voltage profile have beenalso studied by using OLTCs [13]. One of the most important devices to be utilized for the voltage 129 Vol. 2, Issue 1, pp. 129-138
  2. 2. International Journal of Advances in Engineering & Technology, Jan 2012.©IJAET ISSN: 2231-1963regulation is the AVRs which can be operated in manual or automatic mode. In the manual mode, theoutput voltage can be manually raised or lowered on the regulator’s control board and it could bemodelled as a constant ratio transformer in power flow algorithms [14]. In the automatic mode, theregulator control mechanism adjusts the taps to assure that the voltage being monitored is withincertain range [16].Optimal power flow analysis is used to determine the optimal tap position and the ON/OFF state ofthe capacitor banks. The same problem is solved by Vu et al. [7] using the loss equation as theobjective function and voltage inequalities as constraints through the use of an artificial neuralnetwork. Safigianni and Salis [10] proposed the number and location of AVRs by using a sequentialalgorithm. In addition to this, the objective function is defined by using the AVR’s investment andmaintenance costs and also the cost of the total energy losses. Chiou et al. [15] initially attempted tosolve the problem of voltage regulator by changing the tap positions at the substation and later solvedthe capacitor problem. J. Mendoza et al. [17] developed a method for optimal location of AVRs inradial distribution networks by using simple genetic algorithms. However, there are only a fewpublications that have treated the complex problem of the optimal location of the AVRs in distributionsystems, despite the fact that the benefits of including AVR devices. The automatic voltage regulators(AVRs) are included into the sweep based methods and tested by using two distribution testsystems.The proposed method deals with the placing of voltage regulator and tap position ofregulators for power loss reduction and voltage profile improvement [18]. Daniela Proto, PietroVarilone et al[19] explained about Voltage Regulators and Capacitor Placement in Three-phaseDistribution Systems with Non-linear and Unbalanced Loads. Multiobjective Location of AutomaticVoltage regulators in a radial Distribution Network Using a Micro Genetic Algorithm is given in [20].Optimal Distribution Voltage Control and losses minimization suitable methods are proposed in [21],[22]. Integrated volt/VAr control in distribution systems is illustrated in [23],[24]. Impact ofDistribution Generation on voltage Levels in Radial Distribution Systems using Voltageregulators/controllers in[26],[27] are proposed to improve voltage profit. This paper, explains mathematical model, Algorithm for finding the tap settings of a voltageregulator, Implementation of PSO and results and discussions. The branch that has the highest voltagedrop is picked as the best location for the voltage regulator placement. PSO is used to find theselection of tap position of the voltage regulator. to obtain the tap position of the voltage regulatorsthat maintain the voltages within the limits of the unbalanced radial distribution systems so as tominimize an objective function, which consists of power loss.II. MATHEMATICAL FORMULATIONIn this paper in order to maintain the voltage profile and to reduce the power losses, these voltageregulators are installed in the distribution system. The optimization problem has been presented intotwo sub problems: Locating the AVRs on the network and the selection of the tap position of AVRs.2.1 Optimal location of Automatic Voltage Regulators (AVR)The optimal location of voltage regulator (AVR) is defined as function of two objectives, onerepresenting power loss reduction and the other one representing the voltage deviations but both areessential to secure the power supply. It is difficult to formulate the problem in terms of cost incidenceof these objectives over the system of operation because even when the cost incidence of power lossesis clear it is not the same for keeping the voltage values at the buses close to the rated value.The objective function to be minimized is nbMinimize f = ∑ Ploss abc ′ (1) j =1 jWhere, P ′ abc is the active power loss in the jth branch after voltage regulator placement. loss j‘nb’ is the number of branches in the system. 130 Vol. 2, Issue 1, pp. 129-138
  3. 3. International Journal of Advances in Engineering & Technology, Jan 2012.©IJAET ISSN: 2231-19632.2 Tap Position SelectionIn general, voltage regulator position at bus ‘q’ can be calculated as ph′ ph ph (2) V = V ± Tap ×V q q ratedTap position (tap) can be calculated by comparing voltage obtained before VR installation with thelower and upper limits of voltage. ‘+’ for boosting of voltage ‘-’ for bucking of voltage The bus voltages are computed by load flow analysis for every change in tap setting ofvoltage regulators, till all bus voltages are within the specified limits.III. ALGORITHM FOR FINDING THE TAP SETTINGS OF A REGULATORStep 1 : Read the system and regulator dataStep 2 : Calculate the branch current in which regulator is inserted from the backward sweep.Step 3 : Find the CT ratio for three phases as ph ph CT p CT ph = Whereas CTs =5Amps, (3) ph CT sStep 4 : Convert the R and X values from volts to ohms as ph R − jX   Setting Setting  volts ph   (4) (R − jX )ohms = CT s of current phStep 5: Calculating current in the compensator ph (current in the branch) ph (5) I comp = CT ratio phStep 6: Calculate the input voltage to the compensator as (Voltage at the sending end of the branch) ph ph V reg = (6) PT ratio phStep 7: Voltage drop in the compensator circuit is ph ph ph V = (R + jX ) I (7) drop ohms compStep 8: Voltage across the voltage relays in three phases ph ph ph (8) V = V reg − V R dropStep 9: Finding the tapping of the regulator ph (lower limit of the voltage limit ) ph −V (9)Tap ph = R (change in voltages for a step change of the regulator) phStep 10: Voltage output of the regulator ph Vro = (voltageof the sendingend of the branch)ph ±Tap ph ×(0.00625) (10)‘+’ For raise‘_’ For lowerStep 11: StopIV. IMPLEMENTATION OF PSOIn this section, the optimal voltage regulator tap setting at candidate node of the unbalanced radialdistribution system is selected using PSO. 131 Vol. 2, Issue 1, pp. 129-138
  4. 4. International Journal of Advances in Engineering & Technology, Jan 2012.©IJAET ISSN: 2231-19634.1 Initialization of PSO ParametersThe control parameters such as lower and upper bounds of node voltage and tap setting of voltageregulators are selected as initialize parameters. Randomly generate an initial swarm (array) ofparticles with random positions and velocities.4.2 Evaluation of Fitness FunctionThe fitness function should be capable of reflecting the objective and directing the search towardsoptimal solution. Since the PSO proceeds in the direction of evolving best-fit particles and the fitnessvalue is the only information available to the PSO, the performance of the algorithm is highlysensitive to the fitness values. For each particle or swarm, the voltage regulators are placed at thesensitive nodes and run the load flow to calculate the losses, net saving using Eqn.(1) and these netsaving becomes the fitness function of the PSO (as saving are maximized).4.3 Optimal SolutionOptimal solution (the best position and the corresponding fitness value) to the target problem.Information of the best position includes the optimal location and number of voltage regulators, andthe corresponding tap setting value represents the maximizing the total saving of the system.Accordingly, the optimal location and number of voltage regulators with tap setting at each node canbe determined.This modification can be represented by the concept of velocity (modified value for the currentpositions). Velocity of each particle can be modified by the following equation Vi k +1 = WVi k + C1 rand 1 × [ Pbest i − X ik ] + C 2 rand 2 × [Gbest − X ik ] (11)where,Vik : Velocity of particle i at iteration k,Vik+1 : Modified velocity of particle i at iteration k+1,W : Inertia weight,C1,C2 : Acceleration Constants,rand1,rand2 : Two random numbers Xki : Current position of particle i at iteration k,Pbesti : Pbest of particle i,Gbest : Gbest of the group.In the equation (4), kThe term rand1 × (Pbest i - X i ) is called particle memory influence kThe term rand2 × (Gbest - Xi ) is called swarm influence.The rand1, rand2 are the two random numbers with uniform distribution with range of { 0.0 to 1.0 }W is the inertia weight which shows the effect of previous velocity vector on the new vector. Suitableselection of inertia weight W provides a balance between global and local exploration, thus requiringless iteration on average to find optimal solution. A larger inertia weight ‘W’ facilitates globalexploration, while smaller inertia weight ‘W’ tends to facilitates local exploration to fine tune.The following inertia weight is usually utilized in equation (11): Wmax -WminW=Wmax - ×iter (12) itermaxWhere,Wmax : Initial value of the Inertia weight,Wmin : Final value of the Inertia weight,itermax : Maximum iteration number,iter : current iteration number.Accordingly, the optimal types and sizes of voltage regulators to be placed at each compensation nodecan be determined. 132 Vol. 2, Issue 1, pp. 129-138
  5. 5. International Journal of Advances in Engineering & Technology, Jan 2012.©IJAET ISSN: 2231-19634.4 Algorithm for Optimal Location using PLI and Tap setting of VR using PSOThe detailed algorithm is to determine optimal location along with tap setting of voltage regulator isgiven below.Step 1: Read system data such as line data and load data of distribution system.Step 2: Initialize the PSO parameters such as Number of Agents (M), Number of Particles (N), Number of Iterations (Kmax), Initial value of Inertia weight (Wmax), Final value of Inertia weight (Wmin), Acceleration Constants (C1 & C2).Step 3: Initialize the parameters as explained in section 4.(i)Step 4: Obtain the optimal location of VR by using PLI (Power Loss Index) as input.Step 5: Initialize the swarm by assigning a random position and velocity in the problem hyperspace to each particle, where each particle is a solution of tap setting of VR.Step 6: Run the load flow and compute the fitness value of each particle using equation (11).Step 7: Compare the present fitness value of ith particle with its historical best fitness value. If the present value is better than Pbest update the Pbest, else retain Pbest as same.Step 8: Find the Gbest value from the obtained Pbest values.Step 9: Update the particle positions & velocity using eqns. (11) & (12).Step 10: Apply boundary conditions to the particlesStep 11: Execute steps 6-10 in a loop for maximum number of iterations (Kmax).Step 12: Stop the execution and display the Gbest values as the final result for optimal tap setting of voltage regulator. V. RESULTS AND DISCUSSIONThe performance of the proposed method is evaluated for test system of 25 bus URDS for voltageregulator placement to find placing and tap settings of the voltage regulator. For the positioning ofvoltage regulators, the upper and lower bounds of voltage are taken as ± 5% of base value. Properallocation of VR gives minimum losses in URDS and improves performance of the system. The realand reactive power losses of given test system is controlled by controlling voltage regulator size andlocation. The PSO Parameter values for voltage regulator placement: Number of Particles (N) =20,Number of Iterations (Kmax) =100, Initial value of the inertia weight (Wmax) =0.9 ,Final value of theinertia weight (Wmin) =0.4, Acceleration constants, (C1 & C2)=4. The proposed method is illustratedwith test system consisting of 25 bus URDS.5.1 Case StudyPower loss indices for 25 bus URDS is shown in the Figure.1. From the Figure.1 it can be concludedthat the power loss index above 0.6 is the minimum voltage point to locate voltage regulator. Theproposed algorithm is tested on 25 bus URDS as shown in Figure 2. The line and the load data of thissystem is given in [18]. The tap settings of the regulator are obtained with PSO algorithm. The singleline diagram of 25 bus URDS after voltage regulator placement is shown in Figure.2 Figure.1 Power loss indices for 25 bus URDS 133 Vol. 2, Issue 1, pp. 129-138
  6. 6. International Journal of Advances in Engineering & Technology, Jan 2012.©IJAET ISSN: 2231-1963 Figure. 2 Single line diagram of 25 bus URDS after voltage regulator placement. Figure.3 Voltage profit Figure 4. Real power loss 134 Vol. 2, Issue 1, pp. 129-138
  7. 7. International Journal of Advances in Engineering & Technology, Jan 2012.©IJAET ISSN: 2231-1963 Figure.5 Reactive power losses Table: 1 Summary of test results of 25 bus URDS with voltage regulator placement.From the Figure.2 it can be concluded that 1st branch having more drop than others. Therefore voltageregulator should be placed in this branch. It is boosted the total network voltage intern power lossesare minimized.Voltage profit values, active and reactive power loss and summary of test results of 25 bus URDS forvoltage regulator placement are given in figure.3, figure.4 and table.1 respectively. From table 1, it isobserved that the minimum voltages in phases A, B and C are improved from 0.9284, 0.9284 and0.9366 p.u (without Regulators) to 1.0, 1.0 and 1.0 p.u (with Regulators) respectively and the activepower loss in phases of A, B and C is reduced from 52.82, 55.44 and 41.86 kW to 39.16, 40.99 and31.65 kW respectively. Hence, there is an improvement in the minimum voltage and reduction in 135 Vol. 2, Issue 1, pp. 129-138
  8. 8. International Journal of Advances in Engineering & Technology, Jan 2012.©IJAET ISSN: 2231-1963active power loss when compared with the before voltage regulator placement and after voltageregulator placement. The total active power loss Vs generation number of 25 bus URDS is shown inFigure 6. Figure. 6 Total Active Power loss Vs Generation number of 25 bus URDSVI. CONCLUSIONSThis paper presents a simple method to determine optimal allocation and tap setting of voltageregulators in Unbalanced Radial Distribution Systems through voltage drop analysis and PSOalgorithm respectively. The effectiveness of the PSO has been demonstrated and tested. The proposedPSO based methodology was applied to 25 bus URDS. The obtained solution has succeeded inreducing total active power losses 25.43% in 25 bus URDS. From the test results, it can be said thatthe proposed model is valid and reliable, and the performance of the algorithms is not significantlyaffected from the inclusion of regulator modelling. The power loss per phase of unbalanceddistribution system can be reduced by proper placement of voltage regulator. In addition to power lossreduction, the voltage profile also improved by the proposed method. The time of execution isreduced from 73.7 to 66.20 seconds for the same configuration system.REFERENCES[1] R.R. Shouts, M.S. Chen, and L. Schwobel, “Simplified feeder modelling for load flow calculations”, IEEE Transactions Power Systems, vol.2, pp.168-174, 1987.[2] T.-H. Chen, M.-S. Chen, K.J. Hwang, P. Kotas, and E. A. Chebli, “ Distribution system power flow analysis – A rigid approach”, IEEE Transactions on Power Delivery, vol. 6, pp. 1146–1152, July 1991.[3] D. Rajicic, R. Ackovski, and R. Taleski, “Voltage correction power flow”, IEEE Transactions on Power Delivery, vol. 9, pp. 1056–1062, Apr. 1994.[4] S.K. Chang, G. Marks, and K. Kato, “Optimal real time voltage control”, IEEE Transactions Power Systems, vol. 5, no. 3, pp. 750–758, Aug. 1990.[5] C. J. Bridenbaugh, D. A. DiMascio, and R. D’Aquila, “Voltage control improvement through capacitor and transformer tap optimization”, IEEE Transactions Power Systems, vol. 7, no. 1, pp. 222– 226, Feb. 1992.[6] C. S. Cheng and D. Shirmohammadi, "A Three Phase Power Flow Method for Real Time Distribution System Analysis", IEEE Transactions on Power Systems, vol. 10, no. 2 pp 671- 679, May 1995.[7] H. Vu, P. Pruvot, C. Launay, and Y. Harmand, “An improved voltage control on large-scale power systems”, IEEE Transactions Power Systems, vol. 11, no. 3, pp. 1295–1303, Aug. 1996. 136 Vol. 2, Issue 1, pp. 129-138
  9. 9. International Journal of Advances in Engineering & Technology, Jan 2012.©IJAET ISSN: 2231-1963[8] Z. Gu and D. T. Rizy, “Neural network for combined control of capacitor banks and voltage regulators in distribution systems”, IEEE Transactions Power Delivery, vol. 11, no. 4, pp. 1921–1928, Oct. 1996.[9] M. M. A Salama, N. Manojlovic, V. H. Quintana, and A. Y. Chikhani, “Real-Time Optimal Reactive Power Control for Distribution Networks”, International Journal of Electrical Power & Energy Systems, vol. 18, no. 3, pp. 185–193, 1996.[10] A. Safigianni and G. Salis, “Optimal voltage regulator placement in radial distribution network,” IEEE Trans. on Power Systems, vol. 15, no. 2, pp. 879–886, May 2000.[11] M. A. S. Masoum, A. Jafarian, M. Ladjevardi, E. F. Fuchs, and W. N Grady, “Fuzzy approach for optimal Placement and sizing of capacitor banks in the presence of harmonic”, IEEE Transactions Power Delivery, vol. 16, no. 2, pp. 822–829, Apr. 2004.[12] B. Alencar de Souza, H. do Nascimento Alves, and H. A. Ferreira,“Micro genetic algorithms and fuzzy logic applied to the optimal placement of capacitor banks in distribution networks,” IEEE Transactions Power Systems, vol. 19, no. 2, pp. 942–947, May 2004.[13] B. Milosevic and M. Begovic, “Capacitor placement for conservative voltage reduction on distribution feeders,” IEEE Transactions Power Delivery, vol. 19, no. 3, pp. 1360–1367, July 2004.[14] M. A. S. Masoum, M. Ladjevardi, A. Jafarian, and E. Fuchs, “Optimal placement, replacement and sizing of voltage regulators in distorted distribution networks by genetic algorithms”, IEEE Transactions Power Delivery, vol. 19, no. 4, pp. 1794–1801, Oct. 2004.[15] J. Chiou, C. Chang, and C. Su, “Ant direction hybrid differential evolution for solving large capacitor placement problems”, IEEE Transactions Power Systems, vol. 19, no. 4, pp. 1794–1800, Nov. 2004.[16] A. Augugliaro, L. Dusonchet, S. Favazza, and E. Riva, “Voltage regulation and power losses minimization in automated distribution networks by an evolutionary multiobjective approach,” IEEE Trans. Power Syst., vol. 19, no. 3, pp. 1516–11527, Aug. 2004.[17] J. Mendoza et, al “optimal location of voltage regulators in radial distribution networks using genetic algorithms,” in Proceedings 15th power systems computation conference, Bellgium, Augest 2005.[18] J.B.V. Subramnyam, “Optimal capacitor placement in unbalanced radial distribution networks Journal of Theoretical and Applied Information Technology vol:6,N0:1,pp106-115. 2009.[19] Daniela Proto, Pietro Varilone, ” Voltage Regulators and Capacitor Placement in Three-phase Distribution Systems with Non-linear and Unbalanced Loads” International Journal of Emerging Electric Power Systems, Vol. 7, No.4, Nov. 2010.[20] J.E. Mendoza, D.A. Morales, R.A.Lopez, E.A.Lopez, “Multiobjective Location of Automatic Voltage regulators in a radial Distribution Network Using aMicro Genetic Algorithm” IEEE Transactions Power Systems, vol. 22, no. 1, pp. 404–412, Feb. 2007.[21] T.Senjyu, Y.Miyazato, A. Yona, N.Urasaki, T.Funabashi,” Optimal Distribution Voltage Control and Coordination With Distributed Generation” IEEE Transactions Power Delivery, vol. 23, no. 2, pp. 1236–1242, April 2008.[22] H.A Attia, “ Optimal voltage profile control and losses minimization of radial distribution feeder” Power System Conference, (MEPCON 2008), pp 453-458,March 2008.[23] P.V.V.RamaRao, S.Sivanagaraju, ”Voltage Regulator Placement In Radial distribution Network Using Plant Growth Simulation Algorithm” International Journal of Engineering, Science and Technology, Vol. 2, No. 6, pp. 207-217, 2010.[24] V. Borozan, M.E.Baran,D. Novosel,” Integrated volt/VAr control in distribution systems” IEEE Power Engineering Society Winter Meeting, vol. 3, pp. 1485–1490, Feb 2010.[25] B.A. De Souza, A.M.F de Almeida, ” Multi objective Optimization and Fuzzy Logic Applied to Planning of the Volt/ Var Problem in Distributions Systems” IEEE Transactions Power Systems, vol. 25, no. 3, pp. 1274–1281, Aug. 2010.[26] Srikanth Apparaju, Sri Chandan K “impact of Distribution Generation on voltage Levels in Radial Distribution Systems” International Journal of Engineering Research and Applications Vol. 1, Issue 2, pp.277-281, 2010.[27] Jianzhong Tong; Souder, D.W. Pilong, C. Mingye Zhang, Qinglai Guo, Hongbin Sun, Boming Zhang,” Voltage control practices and tools used for system voltage control of PJM” IEEE power and Energy Society General Meeting, pp.1-5, July 2011.AuthorsP. Umapathi Reddy: He Received B.E from Andra University and M.Tech.,(ElectricalPower Systems) from Jawaharlal Nehru Technological University, Anantapur, India in 1998and 2004 respe ctively, Now he is pursuing Ph.D. degree. Currently he is with Department ofElectrical and Electronics Engineering, Sree Vidyanikethan Engineering College, Tirupati,India. His research interest includes Power distribution Systems and Power System operation 137 Vol. 2, Issue 1, pp. 129-138
  10. 10. International Journal of Advances in Engineering & Technology, Jan 2012.©IJAET ISSN: 2231-1963and control. He is Life Member of Indian Society for Technical Education.S. Sivanaga Raju: He received B.E from Andra University and M.Tech.degree in 2000 fromIIT, Kharagpur and did his Ph.D from Jawaharlal Nehru Technological University, Anantapur,India in 2004. He is presently working as Associate professor in J.N.T.U.College ofEngineering Kakinada,(Autonomous) Kakinada, Andrapradesh, India. He received two nationalawards (Pandit Madan Mohan Malaviya memorial Prize and best paper prize award from theInstitute of Engineers (India) for the year 2003-04. He is referee for IEEE journals. He hasaround 75 National and International journals in his credit. His research interest includes Powerdistribution Automation and Power System operation and control.P. Sangameswara Raju He is presently working as professor in S.V.U.College Engineering,Tirupati. Obtained his diploma and B.Tech in electrical Engineering, M.Tech in power systemoperation and control and Ph.D in S.V.University, Tirupati. His areas of interest are powersystem operation, planning and application of fuzzy logic to power system, application of powersystem like non-linear controllers. 138 Vol. 2, Issue 1, pp. 129-138

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