Faculty Publications
Permanent URI for this communityhttps://idr.nitk.ac.in/handle/123456789/18736
Publications by NITK Faculty
Browse
15 results
Search Results
Item Design and simulation of quadrilateral relays in ac transmission lines with vsc-based hvdc systems under phase-to-ground fault condition(Politechnica University of Bucharest Splaiul Independentei 313 - Sector 6 Bucharest 77206, 2019) Muniappan, M.; Vittal, K.P.Voltage source converters (VSC)-based high voltage direct current (HVDC) transmission system can be used to integrate the offshore wind power generation with an AC grid. Due to the interconnection of VSC-HVDC system with the AC grid, an operation of distance relays might get affected. Also, fault resistance plays a significant role in the performance of ground relays. The ground faults have higher fault resistance causes the accuracy of the ground relay gets affected significantly. In this paper, the three-zone quadrilateral characteristic-based distance relay is designed to protect the AC transmission lines under phase-to-ground fault with fault resistance. Simulation studies are carried out to test the performance of the quadrilateral relay under phase-to-ground fault including various fault resistance cases in an AC transmission line with the effect of VSC-HVDC system. The impact of the dynamic conditions of the VSC-HVDC system on the performance of the quadrilateral relays under phase-to-ground fault with fault resistance cases is presented. Also, the performance comparison of the quadrilateral relay with the mho relay under such conditions is presented. © 2019, Politechnica University of Bucharest. All rights reserved.Item Performance Evaluation of Distance Relay in the Presence of Voltage Source Converters-Based HVDC Systems(Korean Institute of Electrical Engineers elecjour@kiee.or.kr, 2019) Muniappan, M.; Vittal, K.P.Voltage source converters (VSC)-based high voltage direct current (HVDC) link is an economical option for the long distance bulk power transmission, and it can be used to interconnect the offshore wind farms with an AC grid. Due to the penetration of VSC-HVDC system into the AC grid, the performance of the distance relay gets affected when a transmission line close to the point of common coupling (PCC) subjected to power system disturbances. In such condition, the PCC voltage is increased due to the VSC-HVDC control action, that causes the Zone-2 fault can be seen as a Zone-3 fault. As a result, the miscoordination of Zone-2 protection can occur in the distance relays. This paper presents both the analytical and simulation studies carried out on a VSC-HVDC system influence on the distance relay performance under fault conditions using PSCAD/EMTDC. Simulation results show that the presence of VSC-HVDC system greatly affects the performance of the Zone-2 and Zone-3 relay in an AC transmission line. Besides, the maloperation of the Zone-2 and Zone-3 relay is mitigated by varying the AC voltage reference input of the decoupled d-q controller of VSC-HVDC. Also, the effect of fault resistance on Zone-1 ground relay performance is analyzed. © 2019, The Korean Institute of Electrical Engineers.Item DC Fault Protection in Multi-terminal VSC-Based HVDC Transmission Systems with Current Limiting Reactors(Korean Institute of Electrical Engineers, 2019) Muniappan, M.; Vittal, K.P.Multi-terminal VSC-based HVDC transmission system is the recent interest for grid integration of large-scale offshore wind farms. Protection of multi-terminal voltage source converters (VSC)-based HVDC transmission systems against DC faults is challenging. This paper presents a single-ended protection scheme for DC faults in a three-terminal VSC-HVDC transmission system. The under-voltage criterion is used to distinguish the DC faults from the transient and normal conditions. The rate of change of DC voltage and current as well as the variation of transient energy is used to discriminate the internal faults from the external faults. The DC fault current has very high value within a few milliseconds during the transient phases such as the capacitor discharging and diode freewheeling stages. Therefore, current limiting reactors are introduced in series with the DC circuit breaker to maintain the DC fault current within the breaker capacity. The single-ended protection scheme is tested with the three-terminal VSC-HVDC transmission system with current limiting reactors for various DC fault conditions. The DC fault data is generated from PSCAD/EMTDC simulation and the protection scheme is tested in MATLAB environment. Test results show that the proposed protection scheme gives reliable protection for the DC faults in a three-terminal VSC-HVDC transmission system. © 2019, The Korean Institute of Electrical Engineers.Item A Self-Balancing Five-Level Boosting Inverter with Reduced Components(Institute of Electrical and Electronics Engineers Inc., 2019) Sandeep, N.; Jagabar Sathik, J.S.; Yaragatti, U.R.; Krishnasamy, K.Two-Stage boosting multilevel inverters (MLIs), which are highly suitable for photovoltaic power plants, are known to suffer because of the high voltage stress on the switches of second stage. One of the ways to confront this issue is through eliminating the front-end booster. However, this leads to increased structural and control complexity of the resulting integrated boosting MLI. This letter presents a single-stage boosting MLI requiring lesser number of switches, diodes, and capacitors for renewable power generation applications. It requires nine switches and only one capacitor for five-level voltage generation. The topology has inherent self-balancing capability, thereby does not need additional balancing circuitry. The proposed topology has a uniform peak inverse voltage stress on the switches of value equal to the input dc voltage. A less complicated logic-form-equations-based gating pulse generation scheme is designed for enabling the proposed MLI to maintain its capacitor voltage. Further, a comparative study with state-of-the-art topologies is carried out to demonstrate the superior performance of the proposed topology. Finally, the feasibility of the proposed topology is validated through experimental tests and the corresponding results are elucidated. © 1986-2012 IEEE.Item Novel active clamped Y-source network for improved voltage boosting(Institution of Engineering and Technology JBristow@theiet.org, 2019) Reddivari, R.; Jena, D.Y-source impedance networks are one of the prominent two-port networks for DC–DC and DC–AC applications with the higher boosting ability and reduced stress across the switching elements. However, the boosting ability of the Y-source converter needs better magnetic coupling between the windings. The loosely coupled inductors cause high-voltage spikes and poor voltage regulation. Use of highly rated switches or incorporation of the proper clamping circuit is essential to improve the performance Y-source converter. It is always better to go with clamping/absorbing circuits instead of the selection of highly rated devices. Various passive and active clamping/absorbing circuits are introduced in literature to suppress the voltage spikes at the expense of higher component count. This article proposes a novel active clamped Y-source impedance network and its family by adding one additional clamping diode to the existing type-I improved Y-source network. Compared to other Y-source networks, the proposed networks absorb the voltage spikes with reduced passive component count and re-utilise the absorbed energy to enhance the voltage gain in the presence of leakage inductance and winding equivalent series resistance. Finally, one of the proposed impedance networks, i.e. an active clamped Y-source DC–DC converter, has been verified experimentally using a ferrite core. © The Institution of Engineering and Technology 2019.Item Experimental verification of a hybrid multilevel inverter with voltage-boosting ability(John Wiley and Sons Ltd vgorayska@wiley.com Southern Gate Chichester, West Sussex PO19 8SQ, 2020) Shiva Naik, B.; Yellasiri, Y.; Venkataramanaiah, J.A new nine-level natural-balanced boost hybrid multilevel inverter (BH-MLI) is proposed in this paper. Each phase of the proposed BH-MLI is designed with only 11 semiconductor switches and two electrolytic capacitors. Here, the capacitor voltages are balanced by utilizing the series-parallel and natural balancing techniques effectively. Furthermore, the proposed circuit eradicates the multiple DC sources by introducing a single DC link for single- and three-phase applications. The proposed topology can be easily extendible to obtain higher level output voltage waveform due to its modular-switched capacitor cells (SCCs). Besides, the higher voltage level generation does not pose high-voltage stress on any of the topology components, as the blocking voltage of all devices within the source voltage magnitude. Further, a quantitative comparison is conducted among the state-of-art switched-capacitor multilevel inverter (SC-MLIs) to highlight the superiority of the proposed configuration. Finally, the performance of the proposed BH-MLI is experimentally validated with phase disposition-pulse width modulation (PD-PWM) and round control method at different modulation indices, load conditions. © 2020 John Wiley & Sons, Ltd.Item A New Single-Source Nine-Level Quadruple Boost Inverter (NQBI) for PV Application(Institute of Electrical and Electronics Engineers Inc., 2022) Singh, A.K.; Raushan, R.; Mandal, R.K.; Ahmad, M.W.Multi-level inverters (MLIs) with switched capacitors are becoming popular due to their utilization in AC high-voltage applications as well as in the field of renewable energy. To achieve the required magnitude of output voltage, the switched capacitor (SC) technique employs a lesser number of DC sources in accordance with the voltage across the capacitor. Designing an efficient high-gain MLI with fewer sources and switches needs a rigorous effort. This paper introduces a prototype of a nine-level quadruple boost inverter (NQBI) topology powered by one solar photo-voltaic source using fewer capacitors, switches, and diodes when compared to the other SC-MLIs topology. The suggested NQB inverter produces nine levels of voltage in its output by efficiently balancing the voltages of the two capacitors. The various SC-MLIs are compared in order to highlight the benefits and drawbacks of the proposed nine-level quadruple boost inverter (NQBI) topology. To validate the efficacy of the proposed solar photovoltaic based NQBI without grid connection, detailed experimental results are presented in a laboratory setting under various test conditions. © 2013 IEEE.Item A Novel Approach for Steady State Calculations of VSC-HVDC Connected PMSG Based Offshore Wind Farms Integrated into Multi-Machine Systems(Taylor and Francis Ltd., 2023) Rashmi, n.; Gaonkar, D.N.Offshore wind farms equipped with Direct Drive Permanent Magnet Synchronous Generators (DD-PMSG) are drawing increased attention due to their advantage over other variable speed technologies. VSC-HVDC links are considered the most suitable option for transferring power to the onshore system. The integration of VSC-HVDC connected DD-PMSG based offshore wind farms into multi-machine systems is explored in this paper. A novel approach for power flow and initial condition calculations is proposed to facilitate dynamic analysis of the system. For three cases of the most commonly specified quantities of the wind farm, efficient methods have been described. The cases comprise combinations of data like the total output of the wind farm, the number of wind turbines, the wind speed, or the output of individual wind turbine, which are frequently given in literature. This approach enables the user to build the dynamic model of the system in any basic graphical dynamic modeler and numerical computational software without requiring power system toolboxes or electromagnetic transient packages. The proposed methods are highly effective for studies focusing primarily on the dynamic aspects and controls of the system. Case studies and simulations are conducted to verify the proposed technique. © 2023 Taylor & Francis Group, LLC.Item A non-isolated bidirectional high gain integrated multiport converter for grid tied solar PV fed telecom load(John Wiley and Sons Inc, 2023) Sheeja, V.; Kalpana, R.; Singh, B.; Subramaniam, U.; Muhibbullah, M.A multiport converter (MPC) with a non-isolated high gain bidirectional port is proposed for the grid integration of solar photovoltaic array (SPA) fed telecommunication load. The SPA along with a battery energy storage (BES) meets the power demand of the telecom DC load and the excess/deficit power is exchanged with AC grid. The MPC feeds the DC link of a voltage source converter for bidirectional operation with the AC grid. The small signal analysis of the converter shows that its operation is stable. The SPA, BES, and telecommunication load are rated for lower voltages, consecutively reducing the complexity with series-connected SPA. The proposed MPC possesses the merits of high voltage gain, reduced inductor size, and reduced number of components. Moreover, a power flow management algorithm is devised for the proposed converter that regulates the DC voltage at the telecom load and ensures smooth power flow control among various ports. The MPC is able to operate at various modes by controlling the ports independently. The converter performance during steady state and dynamic operating conditions under various modes are analyzed with detailed simulation studies. An experimental prototype is developed and test results are demonstrated to prove the viability of the designed converter. © 2022 The Authors. IET Power Electronics published by John Wiley & Sons Ltd on behalf of The Institution of Engineering and Technology.Item An Integrated EV Battery Charger With Three-Level Boost PFC Converter and H5-Bridge Based Bidirectional DO-CLL Series Resonant Converter for Wide Battery Voltage Range(Institute of Electrical and Electronics Engineers Inc., 2025) Vinusha, B.; Kalpana, R.; Kishan, D.This article proposes an efficient two-stage ac–dc converter for off-board electric vehicle charging applications over a wide range of battery voltages. The proposed charger integrates a three-phase three-level boost power factor correction (TL-BPFC) converter with a bidirectional dual-output CLL (DO-CLL) series resonant converter. In the ac–dc conversion stage, three switches are controlled using a hysteresis technique to enhance input power quality. The second stage, responsible for dc–dc conversion, incorporates an H5-bridge on the primary side and a voltage doubler circuit on the secondary side, providing decoupled outputs through two high-frequency transformers (HFTs) connected to resonant tanks. This configuration allows flexible adjustment of the resonant tank inputs, which can operate in full-bridge (FB), half-bridge (HB), or inactive (IA) modes. This design provides a key advantage of a wide voltage range during forward and reverse operation using reconfigurable H5 bridge. Additionally, the switches in the DO-CLL achieve zero-voltage switching (ZVS) during turn-on, and the identical HFTs minimize the cross-coupling effect, to enhance the efficiency. A scaled-down laboratory prototype of the off-board EV charger is developed to provide two distinct outputs of 400 V and 200 V, achieving an overall efficiency of 97.6%. © 1982-2012 IEEE.