Faculty Publications
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Item Intelligent approach for efficient operation of electrical distribution automation systems(2003) Manjunatha Sharma, K.; Sreedhar, P.N.The distribution systems play a vital role in making efficient service in terms of power quality, reliability, and economy. The distribution network reconfiguration can be used for planning as well as real time control. This paper presents an efficient approach for network reconfiguration approach based on artificial neural networks. A package "DISTFLOW" is developed adopting the proposed technique. The off-line simulation results and daily load curve data are used for training of the neural network. Further the distribution system operation is optimized by selecting optimum compensation level computed by Genetic Algorithms (G.A). The proposed integrated approach is applied to 140 bus practical system of Surathkal city subdivision, of the power utility Mangalore electricity supply company (MESCOM).Item Investigations on Combined Operation of Industrial Distribution System and utility in Distributed Generation Environment(2006) Manjunatha Sharma, K.; Vittal, K.P.; Nagaraja Rao, T.K.The deregulation regime has given lot of scope for independent power producers to feed power to the utility nearest to the load center. This feature provides opportunities for lot of improvements in distribution system operation. In this paper investigations have been done for integrated operation of the practical MRPL industrial distribution plant having its own captive generation to act as distributed generation source serving neighboring utility loads. The performance of the system is simulated in both cases of industry acting as source and sink depending on the load cycle. The simulation results will serve as useful tool for decision making in power trading during ABT regime. ©2006 IEEE.Item Harmonic current compensation improvement at point of common coupling using hybrid natural green sources(Institute of Electrical and Electronics Engineers Inc., 2017) Nagaraj, C.; Manjunatha Sharma, K.Ideally, distribution utilities are responsible to provide good power at a fixed rated frequency to the consumer end at unity power factor. Due to the bulk usage of non-linear power electronic loads, distribution system network (DSN) suffers large current distortion. Further, the intermittent hybrid natural green sources (HNGS) like PV and PMSG wind grid connected using hysteresis current controller (HCC) through 3-phase VSI effects more distortion of current which contaminates the power quality at the consumer end. Thus power quality is a vital issue which needs to be presented well in this paper. This paper adopts the shunt active filter (SHAF) using real and reactive current (id-iq) control strategy to analyze the case studies with presence and absence of HNGS under unbalanced nonlinear load condition for the reduction in current distortion at distribution utility side. The MATLAB/Simulink examined to validate the performance of id-iq control strategy. © 2017 IEEE.Item Performance analysis of three leg DSTATCOM under distributed generation and fault scenario(Institute of Electrical and Electronics Engineers Inc., 2017) Saralaya, S.; Manjunatha Sharma, K.In modern power distribution system, use of nonlinear loads has increased drastically. Due to these nonlinear loads, power quality of the system is decreasing. Hence there is necessity of improving power quality of the system. Distribution Static Compensator (DSTATCOM) is a shunt connected custom power device, used in distribution system for performance improvement. DSTATCOM will maintain constant voltage at load terminals and maintains the shape of current and voltage by reducing the distortions. This paper presents a case study on investigation of performance of DSTATCOM at different operating scenarios. IEEE 13 bus industrial system is used to study the performance of three leg DSTATCOM. Voltage control mode with PI control is used to control RMS voltage at point of common coupling (PCC). © 2017 IEEE.Item Performance Analysis of Adaptive Speed Reference Tracking QFT Robust Controller for Three Phase Grid connected Wind Turbine under Stochastic Wind Speed Conditions(Institute of Electrical and Electronics Engineers Inc., 2021) Gudimindla, H.; Manjunatha Sharma, K.; Sandhya, S.Due to stochastic nature of wind, stator current harmonics arise in PMSG based wind energy conversion system that causes the oscillations in wind turbine shaft. These oscillations shows adverse effect on lifespan of wind turbine. It is desirable to track the speed reference in grid connected variable speed wind system along with the maximum power extraction. In this sense, this paper presents the robust controller design methodology to achieve the reference speed tracking controller with maximum power extraction capability in variable speed PMSG driven wind turbines. Further, A modified fitness function is introduced to design the automated robust controller using Genetic algorithm in quantitative feedback theory framework. MATLAB simulations are performed on 20 kW three phase grid connected wind system to analyse the dynamic performance of proposed robust controller under step variation and stochastic wind speed conditions. It is evident from the simulations that tracking of reference speed is achieved with proposed controller under power injecting to load and power sharing with grid conditions. © 2021 IEEE.Item Optimal Sizing, Placement and Performance Analysis of DSTATCOM with Improved Controller without Current Sensors(Institute of Electrical and Electronics Engineers Inc., 2021) Saralaya, S.; Manjunatha Sharma, K.The performance analysis of Distribution Static Compensator (DSTATCOM), when it is placed in an optimized location with an improved controller without current sensors is presented in this paper. To obtain optimal location, Ant colony optimization technique is used for the placement of DSTATCOM. To incorporate this compensator in load flow analysis, the modelling is done and rating of DSTATCOM is obtained. The performance analysis of improved controller is presented after placing the DSTACOM in optimized location with optimized size. The actual voltage at bus where DSTATCOM is placed and DC voltage of the converter is taken as control parameters. The proposed optimization placement technique is tested for 207 bus practical distribution system using MATLAB. The performance analysis of studied systems with controller for different operating scenarios such as sag, swell are investigated in MATLAB/SIMULINK software environment. © 2021 IEEE.Item Performance analysis of Grid Integrated Hybrid Renewable Energy System configuration application to Residential Buildings(Institute of Electrical and Electronics Engineers Inc., 2021) Gudimindla, H.; Manjunatha Sharma, K.; Sandhya, S.Recent technological advancements and cost reduction drives increasing the penetration of renewable energy sources with grid. Utilisation factor of renewable energy sources is low due to dependency on the environmental conditions. Basically, hybrid energy systems provide constant, high-quality power for the remote communities. The sizing of the hybrid system is significant to meet the load demand of residential buildings. In this paper, A simple optimal sizing algorithm is used to model the Wind turbine and PV system to meet the residential load. Quantitave feedback theory (QFT) based robust controller is implemented for the proposed sub-module integrated PV converter and the PMSG based wind energy conversion system to extract maximum power using simple genetic algorithm. Performance of the QFT controller is analysed through MATLAB simulations under varying irradiance and wind conditions. © 2021 IEEE.Item A heuristic approach to distributed generation source allocation for electrical power distribution systems(Iran University of Science and Technology, 2010) Manjunatha Sharma, K.; Vittal, K.P.The recent trends in electrical power distribution system operation and management are aimed at improving system conditions in order to render good service to the customer. The reforms in distribution sector have given major scope for employment of distributed generation (DG) resources which will boost the system performance. This paper proposes a heuristic technique for allocation of distribution generation source in a distribution system. The allocation is determined based on overall improvement in network performance parameters like reduction in system losses, improvement in voltage stability, improvement in voltage profile. The proposed Network Performance Enhancement Index (NPEI) along with the heuristic rules facilitate determination of feasible location and corresponding capacity of DG source. The developed approach is tested with different test systems to ascertain its effectiveness.Item Fuzzy PI controller for bidirectional power flow applications with harmonic current mitigation under unbalanced scenario(AIMS Press, 2018) Nagaraj, C.; Manjunatha Sharma, K.The depletion of fossil fuels and environmental concern forces the extraction of power from low carbon fuels causes generation problem due to intermittent solar-wind renewable energy sources and power electronic applications. Furthermore, the significant amount of non-linear loads in the system causes power quality problems. Nowadays, the more and more DC loads like LED lights to save energy consumption are connected to the AC distribution system. These DC loads are connected at DC grid side in order to avoid the extra AC/DC power conversion loss. In this paper, the proposed d-q reference current method applied for shunt active power filter based 3-phase 4-leg bidirectional interfacing converter with fuzzy PI controller to achieve the real power transfer between DC grid side and AC grid side with current harmonics compensation at common connecting point simultaneously under balanced and unbalanced distorted grid and non-linear load conditions. The hysteresis current control comparator without PLL is used to compare actual grid current with reference filter current and generate the switching pulses for driving the bidirectional interfacing converter. The DC grid shunt connected intermittent hybrid solar-wind energy sources are integrating with AC grid utility through bidirectional interfacing converter has been into consideration for simulation studies. The MATLAB/SIMULINK tool is used to yield the improved grid current THD with fuzzy logic controller over PI controller. © 2018 the Author(s), licensee AIMS Press.Item An improved voltage controller for distribution static compensator(International Journal of Renewable Energy Research, 2019) Saralaya, S.; Manjunatha Sharma, K.Distribution System consist of different types of loads like linear and nonlinear load. Due to different types of loads, voltage unbalance and other power quality related issues will occur. To overcome this problem, a voltage source inverter based device called distribution static compensator can be used. In this work, an improved voltage controller for distributed static compensator, based on power balancing theory is presented. The improved controller uses only voltage sensors and this controller is developed by considering unbalanced load conditions. Proportional Integral controller is used for maintaining terminal voltage and DC link voltage. The controller is verified for different voltage disturbances such as sag and swell. MATLAB/SIMULINK package is used to verify the controller using simulation. The controller is also verified using Hardware in the loop simulation using DSPACE and results are presented for different voltage disturbances. © 2019, International Journal of Renewable Energy Research.