Faculty Publications
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Item Application of Fuzzy Logic in Power Quality Assessment of Modern Power Systems(wiley, 2021) Kumar, V.V.; Babulal, C.K.The modern power system network is subjected to several changes due to rapid technological advancements including penetration of renewable energy sources, distributed generation and microgrids. Along with this, the extensive use of power electronic converters had resulted the power quality assessment as an important task that is to be performed for improving the reliability of the system. In these circumstances, the prime concern is to have single index for evaluating power quality which is capable of accounting all the power quality disturbances. This chapter mainly focuses on the significant power quality indices such as power factors and harmonic distortion factors that are related to waveform distortion. The amalgamation of power quality indices namely total harmonic distortion (THD), total demand distortion (TDD), displacement power factor (DPF), transmission efficiency power factor (TEPF) and oscillation power factor (OSCPF) into a single fuzzy logic based power quality index is explained in this chapter. The newly developed power quality index is computed for different distortion conditions in Matlab environment to authenticate its effectiveness and the results obtained are presented in a lucid manner. Finally, this chapter concludes that the advantages of fuzzy logic approach in handling the imprecise data and uncertainties can be exploited for the evaluation of power quality in modern power systems. This helps in better understanding about the severity levels of power quality disturbances and ranking them. © 2021 Scrivener Publishing LLC.Item A system level solution for power quality problems(2005) Padiyar U, U.H.; Mahant-Shetti, S.S.M.; Sumam David, S.The power quality deterioration is still an unsolved problem due to the increased power electronic load getting into the system. Every, consumer friendly equipment is power electronic controlled in one-way or other. The current drawn by all of these equipments are generally non-sinusoidal in nature, and are distorting the voltage wave as well. Many solutions proposed so far, though found useful in some cases have never become a system solution for the power quality deterioration problem. This paper proposes a unique innovative solution to these problems by a correction at the generation level by changing the shape of source wave keeping in view the nature of new loads. This paper presents PSPICE® simulated results to justify the need for source wave shape change, which will act as a system level solution to the limit peak currents drawn by the new generation power electronic loads. © 2006 IEEE.Item Energy audit of a 400/220 kV substation - A case study(2012) Jaralikar, S.M.; Mangalpady, M.The paper highlights the necessity of undertaking performance analysis and energy audit study of an electrical installation, more particularly a power substation on regular basis. A 630 MVA, 400/220 kV substation was identified and a detailed study was carried out to assess the various station performance parameters under different operating conditions. It was observed that the installed capacity of the station (transformer) was very large compared to the actual load it had to supply. Thus the station was under loaded and underutilized for the major period of its operation. This reduced the operational efficiency of the station. Secondly the incoming line voltage level was remaining high during most of the period of operation. Presently voltage is tried to be maintained by switching ON the line reactors at the receiving and sending ends of this station, switching OFF one of the 400 kV incoming lines during off peak loading conditions, thus risking the supply reliability. The present study emphasizes on the urgent need for improving the power quality, streamlining and optimizing the station capacity, operations and its loading pattern. Accordingly suggestions are proposed for the same. © 2011 IEEE.Item A study on hybrid Renewable Energy Source interface to the non-ideal grid at distribution level with power quality improvements(Institute of Electrical and Electronics Engineers Inc., 2016) Jayasankar, V.N.; Gururaj, M.V.; Vinatha Urundady, U.Air pollution is one of the prominent issues that we are facing nowadays. The major contributor for air pollution is the waste output of power plants which uses fossil fuels to generate power. Urbanization and industrialization have changed the lifestyle of human society and the need for electrical energy has enhanced significantly. As the conventional energy sources are not capable of serving the purpose, the researchers have turned their face towards Renewable Energy Sources (RES). Energy sources are scattered across the globe, therefore the available green energy at the distribution level is also used to generate electricity. The hybrid combination of wind/solar systems has proved to be a reliable source to the utility. For extracting maximum power from the RES, battery bank is connected across it. Due to the problem associated with the chemical batteries the wind/solar hybrid combination is directly connected to the grid. There are many issues related to the interconnection of RES to the grid which are addressed with the growth in power electronics field. However the power quality issue occurs due to the presence of non-linear loads at the point of common coupling. Shunt active filter has proved to mitigate the problems associated with the non-linear loads. Researchers have limited their work to interconnection of RES to ideal grid voltages which is not the practical case. In this paper the wind/solar hybrid system is modeled and is interconnected to the unbalanced and distorted grid. Also, RES interfacing inverter is added with shunt active filter functionality and hence overall cost curtailment of the project can be achieved. © 2016 IEEE.Item A new nine-level single-DC source-based inverter topology for distributed generation(Institute of Electrical and Electronics Engineers Inc., 2017) Sandeep, N.; Yaragatti, U.R.Multilevel inverter enables to completely remove the passive filtering requirement at the grid interfacing end, resulting in improved efficiency and reduced cost. These features have led to increasing attention towards their application to medium and high-power arena. In this paper, investigation of a hybrid 9-level inverter topology for grid integration of renewable energy sources is presented. The structural details, operating principle, capacitor voltage balancing control and the main features of the proposed inverter are presented. The proposed topology is compared with other similar 9-level converters to emphasize its superior characteristics and performance. Simulation results demonstrating the grid connected operation of the converter for two test cases are presented. The results affirm the effectiveness of the capacitor voltage balancing control in maintaining capacitor voltages at set values, under steady state and transient operation of the converter. © 2016 IEEE.Item High performance front-end PFC rectifier for telecom power supplies(Institute of Electrical and Electronics Engineers Inc., 2017) P, P.; Kalpana, R.; Singh, B.; Bhuvaneswari, G.High-current low-voltage (HCLV) rectifiers are used in the telecom industries, electroplating and induction heating system. Typical power rating of these rectifiers varies from tens of kW to hundreds of MW. In this paper, a three-phase three-level boost type PWM rectifier is proposed as an active front-end PFC scheme for telecom load. The proposed active front-end PFC converter is modeled by switching cycle average model and relation between duty ratio and the dc-link capacitor voltage is derived as in terms of system input currents. Also, the switching states have been derived for the feasible converter operation. The detailed analysis of front-end PFC converter is carried out by equivalent circuit. The power quality also well improved by proposed active front-end PFC rectifiers. The experimental setup for a 12 kW active front-end PFC rectifier is developed in the laboratory to validate the MATLAB simulation results. © 2016 IEEE.Item Simplified hybrid nine-level stacked multiceli converter with reduced part count for grid-connected applications(IEEE Computer Society, 2017) Sandeep, N.; Yaragatti, U.R.Increasing demand for high-efficiency inverters with improved output waveform quality has enhanced the research in the area of multilevel inverters (MLIs). A dc-ac hybrid inverter formed by cascading a five-level (5L) stacked multicell converter (SMC) and floating capacitor (FC) H-bridge is proposed. It requires only 12 switches and three FCs for nine-level (9L) operation. The most important advantage of the proposed inverter lies in the fact that it requires minimum topological alteration for extending 5L SMC to 9L. FC voltage control strategy and results confirming the effectiveness and operability of the proposed inverter is presented. © 2017 IEEE.Item Enhancement of load voltage compensation using positive sinusoidal sequence regulator in fuzzy logic controlled three phase series active filter(Institute of Electrical and Electronics Engineers Inc., 2018) Jayasankar, V.N.; Kumar, N.B.; Vinatha Urundady, U.This study proposes a controller for series active Alter for enhancement in load voltage compensation. The controller consists of a positive sinusoidal sequence regulator based fundamental voltage calculator, a closed loop fuzzy logic based voltage controller and a pulse width modulation controller. Positive sequence sinusoidal signal regulator effectively eliminates the phase delay introduced while calculating fundamental voltage. Numerical simulations are done for different cases to verify the effectiveness of controller under different system conditions. © 2017 IEEE.Item Design and Development of Multi-Phase Rectifier with Reduced Magnetic Rating(Institute of Electrical and Electronics Engineers Inc., 2018) P, P.S.; Kalpana, R.; Singh, B.This paper proposes a 20-pulse asymmetric multiphase rectifier (AMPR) suitable for medium and high-power applications. Unlike the other state-of-the-art 20-pulse delta connected autotransformers, the proposed delta connected AMPR has an ability to reduce input harmonics, maintains high efficiency and requires a magnetic rating of only 30.12% of the nominal load thereby a significant reduction in space, weight, and overall cost required are the salient features of the proposed AMPR. Firstly, the proposed AMPR configuration is simulated in MATLAB/Simulink environment for evaluating its viability under different loading conditions, and the results are illustrated. Also, a prototype is developed, and the experimental measurements obtained are presented to validate the feasibility and operability of the proposed AMPR. The proposed AMPR offers a total harmonic distortion of 3.7% and can operate at near-unity power factor complying with the IEEE and IEC standards. © 2018 IEEE.Item A 36-Pulse AC-DC Converter with DC Side Tapped Interphase Bridge Rectifier for Power Quality Improvement(Institute of Electrical and Electronics Engineers Inc., 2018) P, P.S.; Kalpana, R.; Chethana, K.S.; Singh, B.This paper presents a circuit configuration to reduce the harmonic contents at the AC mains of a 12-pulse zigzag configured autotransformer based DBR. The proposed circuit configuration employs a tapped interphase bridge rectifier at the DC side of 12-pulse DBR that results in higher pulses in the supply current. Thus, reducing the harmonic content and thereby improving the power quality of the system. Since the autotransformer employed is zigzag configured, the need for ZSBT is eliminated. Moreover, the proposed circuit configuration at the DC side shapes the supply current near to a sine wave. Further, the proposed configuration is analyzed, simulated in MATLAB Simulink and the simulation results are presented, which confirms the improvement in power quality parameters in the input AC line current. Further, the viability of the proposed configuration is verified by experimental results which confirm the suitability of the proposed configuration in AC-DC applications. © 2018 IEEE.