Faculty Publications
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Publications by NITK Faculty
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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 Fuzzy logic based coordinated voltage regulation method for distribution system with multiple synchronous generators(2010) Gaonkar, D.N.; Pillai, G.N.The continued interest in the distributed generation (DG) sources in recent years is leading to the growth of a number of generators connected to distribution networks. The steady-state voltage rise resulting from the connection of these generators can be a major obstacle at the lower voltage levels. Present network design practice is to limit the generator capacity to a level at which the upper voltage limit is not exceeded. This reduces the efficiency of DG system. This paper proposes a coordinated voltage control scheme using fuzzy logic based power factor controller, for distribution network with multiple Distributed generation systems. In the proposed scheme individual generators participate in voltage regulation of the distribution system, based on their participation factor determined using sensitivity analysis. The simulation results presented in the paper show the effectiveness of the method. © 2010 IEEE.Item Fuzzy logic based coordinated voltage regulation method for distribution system with multiple synchronous generators(2010) Gaonkar, D.N.; Pillai, G.N.The continued interest in the distributed generation (DG) sources in recent years is leading to the growth of a number of generators connected to distribution network. One of the major concern due to connection of these generators is the rise in steady state voltage level of distribution system. Present network design practice is to limit the generator capacity to a level at which the upper voltage limit is not exceeded. This reduces the efficiency of DG system. This paper proposes a coordinated voltage control scheme using fuzzy logic based power factor controller, for distribution network with multiple synchronous generators. In the proposed scheme individual generators participate in voltage regulation of the distribution system, based on their participation factor determined using sensitivity analysis. The simulation results presented in the paper show the effectiveness of the method. © 2010 IEEE.Item Voltage estimation in smart distribution networks with multiple DG systems(Institute of Electrical and Electronics Engineers Inc., 2016) Raghavendra, P.; Gaonkar, D.N.Steady state voltage rise problem resulting from the integration of DGs at lower voltage levels can be a major impediment to the growth of distributed generation capacity. With the steady implementation of the smart grid technologies throughout the existing distribution networks, the online voltage control can be achieved. The voltage profile has to be estimated first along the distribution networks for the online voltage control. In this article, a technique to estimate the voltage profile of a radial distribution network with multiple DG systems having different line section impedances with/without laterals is presented. The presented technique is based on estimation of voltages by remote terminal units (RTUs) placed at each DG and at each line capacitor. The presented technique tested on two radial rural distribution systems with/without laterals. Comparative results for different methodologies in estimating the voltage profile are presented. The simulated results using the above method are presented in this paper, considering the multiple DG systems with/without laterals. The reported results show that the method presented is capable of estimating the voltage profile along the distribution network with DGs for online voltage control. © 2015 IEEE.Item Online volt/var control in a smart grid with multiple distributed generation systems(Institute of Electrical and Electronics Engineers Inc., 2017) Raghavendra, P.; Gaonkar, D.N.The higher shares of distributed generation (DG) sources lead to unpredictable rise in voltage level due to intermittent and stochastic characteristics of DGs. This paper intends to report the online Volt/Var control in a smart grid with multiple DG systems. The objective of Volt/Var control is to recover the network voltages within the admissible limits by coordinating the operation of the DG and the OLTC transformer. Firstly, voltage profile of the system is estimated by remote terminal units (RTUs) placed only at DG node. Next, a direct voltage sensitivity based method is developed to choose best DG for reactive power injection in multiple DG environments. Finally, OLTC transformer is employed in voltage regulation process when DGs reactive power is insufficient for maintaining the voltages within predefined limits. The reported method tested on 12-bus radial distribution network to validate the theory. The reported simulation results show that the presented method effectively maintains network voltages within admissible limits. © 2016 IEEE.Item Dynamic performance of microturbine generation system connected to a grid(2008) Gaonkar, D.N.; Pillai, G.N.; Patel, R.N.The interconnection of distribution generation systems into distribution networks has great impact on real-time system operation, control, and planning. It is widely accepted that microturbine generation (MTG) systems are currently attracting a lot of attention to meet customers' needs in the distributed power generation market. In order to investigate the performance of MTG systems, their efficient modeling is required. This article presents the dynamic model of an MTG system, suitable for grid connection to study the performance of the MTG system. The presented model uses back-to-back power electronic converter topology for grid connection, which allows the bidirectional power flow between the grid and MTG system. Thus, the need of separate starting arrangements during launching of the microturbine is avoided. The components of the system are built from the dynamics of each part with their interconnections. The dynamics of the model have been studied under various grid disturbance conditions. The converter control strategies for MTG system operation in grid-connected mode are presented in this article. This article also compares the various grid connection topologies suitable for MTG system interconnection. The simulation results show that the developed model performance is not affected by the grid disturbances considered in the study, and that it has the ability to adjust the supply as per the power requirements of the load within the MTG system rating.Item Seamless transfer of microturbine generation system operation between grid-connected and islanding modes(2009) Gaonkar, D.N.; Pillai, G.N.; Patel, R.N.The intentional islanding operation of grid-connected distributed generation systems can greatly improve the reliability and quality of the power supply. The existing control techniques for distributed generation systems are designed to operate either in the grid-connected or islanding modes of operation, thus, not allowing for both modes to be implemented and transitioned between. In this article, a novel scheme for automatic mode switching of a microturbine-based distributed generation system between the grid-connected and islanding modes of operation is proposed. The presented scheme is based on the phase angle estimated by the phase-locked loop. The developed phase-locked loop provides an accurate estimation of the phase angle even under unbalanced conditions. The presented scheme does not negatively affect the distributed generation system or utility operations and can work even under matching distributed generation and load power ratings. In this work, back-to-back converters are used to interface the microturbine-based distributed generation system to the grid. Converter control strategies developed for both modes of distributed generation operation is also presented. The simulation results show good accuracy of the proposed scheme.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 Assessment of distributed generation source impact on electrical distribution system performance(2010) Sharma, M.; 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. A Priority list is prepared with decreasing values of NPEI so that the designer can select most feasible location. The developed approach is tested with different test systems to ascertain its effectiveness. © 2010 AECE.Item Power control strategy for grid connected permanent magnet synchronous generator of a distributed generation unit(Inderscience Enterprises Ltd., 2014) Vinatha Urundady, V.; Vittal, P.K.This paper describes the studies on the operation and control of a variable speed wave energy conversion system. The wave energy conversion system considered is oscillating-water-column (OWC) based Wells turbine driven permanent magnet synchronous generator connected to the grid by means of fully controlled frequency converter. In such systems primary aim is to achieve a low distortion, high power quality power export from the converter with the objective to regulate the power flow or power factor optimisation. In this paper wave energy conversion system is modelled and control schemes are implemented for regulating the dc link voltage for varying input conditions and for regulating the grid current entering the distribution network and hence the power flow into the grid. Response of the system is investigated under steady state, dynamic and transient conditions. In each case the grid current distortion and the dynamic performance of the converter control schemes are evaluated. © © 2014 Inderscience Enterprises Ltd.