Faculty Publications

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Author: search.filters.author.Raghavendra, P.Has files: No

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    Performance study of roof top wind solar microgrid system in isolated mode of operation
    (Institute of Electrical and Electronics Engineers Inc., 2014) Gaonkar, D.N.; Sabhahit, N.S.; Raghavendra, P.
    The increasing interconnection of distributed generation sources of diverse technologies to low voltage grids introduces considerable complexity in its operation and control. The concept of the microgrid is emerging as a solution to this and also to take full advantage of the potential offered by distributed generation resources. In this paper the performance study of a roof top wind solar hybrid microgrid in isolated mode of operation has been presented. The developed 10 kW microgrid consists of two wind turbine of 3.2 kW each and a PV system of 3.6 kW peak. The microgrid is interfaced to the load through a voltage source inverter. The performance of wind system in the developed microgrid has been investigated under different input conditions and practical results have been reported in this paper. © 2014 IEEE.
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    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.
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    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.
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    Vibration Analysis of Composite Viscoelastic Core Sandwich Beam Using Active Control Techniques
    (Springer Science and Business Media Deutschland GmbH, 2024) Raghavendra, P.; Gatty, A.S.; Rajesh, H.; Deepak, T.N.; Rawal, Y.; Nagiredla, S.; Joladarashi, S.
    Vibration control is swiftly advancing in research, with diverse techniques being investigated to minimize detrimental vibration levels. Compared to metallic alloys, composite materials offer superior material properties while being lightweight. The main objective of this study is to develop active control techniques on Carbon/Glass Epoxy-reinforced composite sandwich beams with viscoelastic core using Proportional Integral Derivative (PID), Linear Quadratic Regulator (LQR), and Linear Quadratic Gaussian (LQG) Controllers. The approach involves conducting an experiment to obtain the Transient Response of the beams subjected to free vibration, which is then utilized to obtain the Transfer Function and State Space variables. MATLAB-Simulink obtained transfer function is used for implementing controllers to actively attenuate vibrational amplitudes and settling time. The outcomes reveal a significant reduction in settling time and vibrational peak amplitudes. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.
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    Online voltage estimation and control for smart distribution networks
    (2016) Raghavendra, P.; Gaonkar, D.N.
    The increasing deployment of Distributed Generation (DG) technologies introduces power quality challenges to the grid, in particular steady state voltage rise at the connection point forDGunits. In most distribution networks, control and monitoring of grid parameters is missing, as well as system security is at risk. Smart grid technologies have the capability to realize the real-time measurements and on-load voltage controls. With the steady implementation of smart grid technologies throughout the existing distribution networks, the online voltage control can be achieved ensuring the power quality and voltage levels within the statutory limits. This study presents a methodology for the estimation of voltage profile in a smart distribution network with DG for the online voltage control, taking into account different line X/R ratios and laterals. This method is based on maximum and minimum voltage estimation by remote terminal units (RTUs) placed only at DG connected bus and at capacitor connected bus. Voltage regulation is carried out based on RTUs estimated values. This work is tested on two radial distribution networks with/without DGs and laterals. Comparative results for voltage magnitudes estimated with different methodology are presented. The reported simulation results show that the method presented is capable of estimating the voltage profile along the distribution network with DGs for the online voltage control, considering different line X/R ratios and laterals. © The Author(s) 2016.
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    Coordinated volt-var control: Online voltage-profile estimation in smart distribution networks
    (Institute of Electrical and Electronics Engineers Inc., 2018) Raghavendra, P.; Gaonkar, D.N.
    The increasing penetration of intermitt ent and stochastic distributed generation (DG) sources in the existing power grid can lead to voltage rise problems. Meanwhile, the rapid development of smart grid technologies calls for effective solutions to realize the real-time measurements and coordinated volt-var control to improve the overall systems voltage profile (VP). This article presents online VP estimation and coordinated volt-var control in a smart distribution network with multiple DG systems. © 1975-2012 IEEE.
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    Voltage Profile Analysis in Smart Grids Using Online Estimation Algorithm
    (Hindawi Limited, 2022) Raghavendra, P.; Nuvvula, R.S.S.; P Kumar, P.P.; Gaonkar, D.N.; Sathoshakumar, A.; Khan, B.
    Voltage rise is the main obstacle to prevent the increase of distributed generators (DGs) in low-voltage (LV) distribution grids. In order to maintain the power quality and voltage levels within the tolerance limit, new measurement techniques and intelligent devices along with digital communications should be used for better utilization of the distribution grid. This paper presents a real-time sensor-based online voltage profile estimation technique and coordinated Volt/VAR control in smart grids with distributed generator interconnection. An algorithm is developed for voltage profile estimation using real-time sensor remote terminal unit (RTU) which takes into account topological characteristics, such as radial structure and high R/X ratio, of the smart distribution grid with DG systems. A coordinated operation of multiple generators with on-load tap changing (OLTC) transformer for Volt/VAR control in smart grids has been presented. Direct voltage sensitivity analysis is used to select a single DG system for reactive power support in multi-DG environment. The on-load tap changing transformer is employed for voltage regulation when generators' reactive power contributions are not enough to regulate the voltages. Simulation results show that the reported method is capable of maintaining voltage levels within the tolerance limit by coordinated operation of DG systems and on-load tap changing transformer. © 2022 P. Raghavendra et al.