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122 results on '"Palaniappan, Rajkumar"'

1. System-level Testing of the Congestion Management Capability of a Hardware-Independent Optimal Power Flow Algorithm

Author

Schwierz, Thomas, Palaniappan, Rajkumar, Molodchyk, Oleksii, and Rehtanz, Christian

Subjects
Electrical Engineering and Systems Science - Systems and Control, B.1.3, B.1.4, B.4.1, B.4.5
Abstract

The integration of distributed energy resources (DERs) into the electrical grid causes various challenges in the distribution grids. The complexity of smart grids as multi-domain energy systems requires innovative architectures and algorithms for system control. While these solutions are good on paper, several testing methods are required to test the applicability of components, functions and entire systems to the existing energy grids. In this paper, a full-scale low-voltage test setup in the Smart Grid Technology Lab (SGTL) at TU Dortmund University is used to evaluate the capability of an Optimal Power Flow Algorithm (OPF) to support voltage control, congestion management, and to provide redispatch to the higher grid levels. While conventional redispatch is commonly done preemptively, this paper analyses the possibility of providing redispatch to the higher voltage levels without taking the future grid state into consideration. The importance of this implementation is that the smart grid application used to execute the OPF is configured based on IEC 61850 data models, making the software independent of the hardware. Such standardised control algorithms are interoperable and can be implemented on any hardware that suits the requirements., Comment: 10 pages, 9 figures, 6 tables, currently in submission for IEEE Transactions on Power Systems

Published
2023

2. Implementation of Machine Learning-based DER Local Control Schemes on Measurement Devices for Counteracting Communication Failures

Author

Palaniappan, Rajkumar, Ceschlaw, Jan-Niklas, Karagiannopoulos, Stavros, and Rehtanz, Christian

Subjects
Electrical Engineering and Systems Science - Systems and Control
Abstract

One of the significant challenges linked with the massive integration of distributed energy resources (DER) in the active distribution grids is the uncertainty it brings along. The grid operation becomes more arduous to avoid voltage or thermal violations. While the Optimal Power Flow (OPF) algorithm is vastly discussed in the literature, little attention has been given to the robustness of such centralised implementation, such as the provision of redundant control solutions during a communication failure. This paper aims to implement a machine learning-based algorithm at each Intelligent Electronic Device (IED) that mimics the centralised OPF used during communication failures using IEC 61850 data models. Under normal circumstances, the IEDs communicate for centralised OPF. In addition, the system is trained offline for all operational conditions and the individual look-up tables linking the actual voltages to the DER setpoints are sent to the respective controllers. The regression models allow for the local reconstruction of the DER setpoints, emulating the overall OPF, in case of a communication failure. In addition to the regression control, the paper also explains an offline learning approach for periodic re-training of the regression models. The implementation is experimentally verified using a Hardware-in-the-loop test setup. The tests showed promising results compared to conventional control strategies during communication failures. When properly trained and coordinated, such an intuitive local control approach for each DER could be very beneficial for the bulk power system. This machine learning-based approach could also replace the existing Q(V) control strategies, to better support the bulk power system., Comment: In proceedings of the 11th Bulk Power Systems Dynamics and Control Symposium (IREP 2022), July 25-30, 2022, Banff, Canada

Published
2022

4. Development of an EEG Controlled System for Neuro-Prosthetics

Author

Rushambwa, Munyaradzi Charles, Gezimati, Mavis, Jeeva, J. B., Palaniappan, Rajkumar, Govindaraj, P., Pondani, Taurayi, Angrisani, Leopoldo, Series Editor, Arteaga, Marco, Series Editor, Chakraborty, Samarjit, Series Editor, Chen, Jiming, Series Editor, Chen, Shanben, Series Editor, Chen, Tan Kay, Series Editor, Dillmann, Rüdiger, Series Editor, Duan, Haibin, Series Editor, Ferrari, Gianluigi, Series Editor, Ferre, Manuel, Series Editor, Jabbari, Faryar, Series Editor, Jia, Limin, Series Editor, Kacprzyk, Janusz, Series Editor, Khamis, Alaa, Series Editor, Kroeger, Torsten, Series Editor, Li, Yong, Series Editor, Liang, Qilian, Series Editor, Martín, Ferran, Series Editor, Ming, Tan Cher, Series Editor, Minker, Wolfgang, Series Editor, Misra, Pradeep, Series Editor, Mukhopadhyay, Subhas, Series Editor, Ning, Cun-Zheng, Series Editor, Nishida, Toyoaki, Series Editor, Oneto, Luca, Series Editor, Panigrahi, Bijaya Ketan, Series Editor, Pascucci, Federica, Series Editor, Qin, Yong, Series Editor, Seng, Gan Woon, Series Editor, Speidel, Joachim, Series Editor, Veiga, Germano, Series Editor, Wu, Haitao, Series Editor, Zamboni, Walter, Series Editor, Zhang, Junjie James, Series Editor, Ray, K. P., editor, Dixit, Arati, editor, Adhikari, Debashis, editor, and Mathew, Ribu, editor

Published
2023
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12. A new species of Cigaritis Donzel, 1847 (Lycaenidae, Aphnaeinae) from the southern Western Ghats of Peninsular India.

Author

Kamaya Naicker, S. Ramasamy, Chandrika, Sujitha Prabhakaran, Kochunarayanan, Baiju, Jose, Jebine, Kripakaran, Manoj, Palaniappan, Rajkumar Chidambaram, Nair, Vinayan Padmanabhan, and Sadasivan, Kalesh

Subjects
LYCAENIDAE, SPECIES, MALE reproductive organs
Abstract

A new species Cigaritis meghamalaiensis sp. nov. (Lycaenidae, Aphnaeinae) is described from the Meghamalai Hills of the Periyar landscape of the southern Western Ghats. Images of adults and illustrations of male genitalia are presented. Information on myrmecophilous immature stages is provided and its ecology is discussed. The new species is very distinct from all the known Cigaritis species in WG, and is diagnosed based on the following combination of characters–upper side of both wings marked extensively blue in males; discal and post-discal bands on forewing underside conjoined and lying parallel from their origin at the costa; post-basal band in hindwing underside continuous and not broken into three smaller bands and this post-basal band ends at vein1b, is not continued along it to reach discal band. The discal and post-discal bands on the underside of the forewing is conjoined and lying parallel from their origin at the costa which is a unique feature that distinguishes the new species from all other Cigaritis species occurring in Peninsular India and Sri Lanka. A key to all known species of Cigaritis from the Western Ghats is provided. [ABSTRACT FROM AUTHOR]

Published
2023
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22. Experimental verification of smart grid control functions on international grids using a real-time simulator

Author

Palaniappan, Rajkumar, Molodchyk, Oleksii, Shariati-Sarcheshmeh, Mahdi, Asmah, Marilyn Winifred, Liu, Jiayan, Schlichtherle, Tobias, Richter, Frank, Kwofie, Ekow Appiah, Festner, Daniel Rios, Blanco, Gerardo, Mutule, Anna, Borscevskis, Olegs, Rafaat, Shady S., Li, Yong, Häger, Ulf, and Rehtanz, Christian

Subjects
Intelligentes Stromnetz, IEC-Norm, Elektrizitätsversorgungsnetz, Erneuerbare Energien, Dezentrale Energieversorgung, Internationaler Vergleich, Netzstabilität, Echtzeitsimulation
Abstract

The drastic increase in distributed energy resources (DERs) leads to challenges in the operation of distribution systems worldwide. While several solutions for grid monitoring and control are available on the market and in literature, this research is the first of its kind aiming to supervise the grid by providing a modular configurable unified hardware and software architecture. The control algorithms are configured using data models according to IEC 61850-7-3 and IEC 61850-7-4. The novel system architecture is a portable, modular and flexible architecture that aggregates smart grid control functions onto a standardised hardware platform, emphasising the need for hardware independence. The central controller contains several smart grid control functions and the various field devices are distributed across the distribution grid. This paper deals with the simulation of different real-world distribution grids on the Real-Time Simulator (RTS) and experimental verification of the control algorithms. Smart grid control functions such as Coordinated Voltage Control (CVC) and Optimal Power Flow (OPF) are experimentally verified on a German grid. The grid dynamics are compared when the central controller executes the CVC against the OPF implementations. The experimental results, advantages and challenges of each control are presented here. The results also showed the variation in grid behaviour when the control parameters were varied. The paper also shows that the algorithm and the choice of the control parameters depend upon the distribution grid's complexity and the system operator's individual needs. The results illustrate the potential of such a universal distribution automation solution for system operators worldwide., IET generation, transmission & distribution;16(13)

Published
2022

23. Experimental verification of smart grid control functions on international grids using a real‐time simulator

Author

Palaniappan, Rajkumar, primary, Molodchyk, Oleksii, additional, Shariati‐Sarcheshmeh, Mahdi, additional, Asmah, Marilyn Winifred, additional, Liu, Jiayan, additional, Schlichtherle, Tobias, additional, Richter, Frank, additional, Kwofie, Ekow Appiah, additional, Festner, Daniel Rios, additional, Blanco, Gerardo, additional, Mutule, Anna, additional, Borscevskis, Olegs, additional, Rafaat, Shady S., additional, Li, Yong, additional, Häger, Ulf, additional, and Rehtanz, Christian, additional

Published
2022
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25. A Review of Optical Ultrasound Imaging Modalities for Intravascular Imaging.

Author

Rushambwa, Munyaradzi Charles, Suvendi, Rimer, Pandelani, Thanyani, Palaniappan, Rajkumar, Vijean, Vikneswaran, and Nabi, Fizza Ghulam

Subjects
ULTRASONIC imaging, ACOUSTIC imaging, INTRAVASCULAR ultrasonography, MAGNETIC resonance imaging, SIGNAL processing, OPTICAL images, LASER ranging
Abstract

Recent advances in medical imaging include integrating photoacoustic and optoacoustic techniques with conventional imaging modalities. The developments in the latter have led to the use of optics combined with the conventional ultrasound technique for imaging intravascular tissues and applied to different areas of the human body. Conventional ultrasound is a skin contact-based method used for imaging. It does not expose patients to harmful radiation compared to other techniques such as Computerised Tomography (CT) and Magnetic Resonance Imaging (MRI) scans. On the other hand, optical Ultrasound (OpUS) provides a new way of viewing internal organs of the human body by using skin and an eye-safe laser range. OpUS is mostly used for binary measurements since they do not require to be resolved at a much higher resolution but can be used to check for intravascular imaging. Various signal processing techniques and reconstruction methodologies exist for Photo-Acoustic Imaging, and their applicability in bioimaging is explored in this paper. [ABSTRACT FROM AUTHOR]

Published
2023
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40. Analysis of wheeze sounds during tidal breathing according to severity levels in asthma patients.

Author

Nabi, Fizza Ghulam, Sundaraj, Kenneth, Lam, Chee Kiang, and Palaniappan, Rajkumar

Subjects
WHEEZE, ASTHMATICS, RESPIRATION, STATISTICAL significance
Abstract

Objective: This study aimed to statistically analyze the behavior of time-frequency features in digital recordings of wheeze sounds obtained from patients with various levels of asthma severity (mild, moderate, and severe), and this analysis was based on the auscultation location and/or breath phase. Method: Segmented and validated wheeze sounds were collected from the trachea and lower lung base (LLB) of 55 asthmatic patients during tidal breathing maneuvers and grouped into nine different datasets. The quartile frequencies F25, F50, F75, F90 and F99, mean frequency (MF) and average power (AP) were computed as features, and a univariate statistical analysis was then performed to analyze the behavior of the time-frequency features. Results: All features generally showed statistical significance in most of the datasets for all severity levels [χ2 = 6.021–71.65, p < 0.05, η2 = 0.01–0.52]. Of the seven investigated features, only AP showed statistical significance in all the datasets. F25, F75, F90 and F99 exhibited statistical significance in at least six datasets [χ2 = 4.852–65.63, p < 0.05, η2 = 0.01–0.52], and F25, F50 and MF showed statistical significance with a large η2 in all trachea-related datasets [χ2 = 13.54–55.32, p < 0.05, η2 = 0.13–0.33]. Conclusion: The results obtained for the time-frequency features revealed that (1) the asthma severity levels of patients can be identified through a set of selected features with tidal breathing, (2) tracheal wheeze sounds are more sensitive and specific predictors of severity levels and (3) inspiratory and expiratory wheeze sounds are almost equally informative. [ABSTRACT FROM AUTHOR]

Published
2020
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48. Development of fuzzy inference system for automatic tea making

Author

Ahamed, Nizam Uddin, primary, Taha, Zahari Bin, additional, Mohd Khairuddin, Ismail B., additional, Rabbi, Mohammad Fazle, additional, Sikandar, Tasriva, additional, Palaniappan, Rajkumar, additional, Ali, Md. Asraf, additional, Rahman, Sam Matiur, additional, and Sundaraj, K., additional

Published
2016
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49. Fuzzy logic controller design for intelligent drilling system

Author

Ahamed, Nizam Uddin, primary, Yusof, Zulkifli, additional, Hamedon, Zamzury, additional, Rabbi, Mohammad Fazle, additional, Sikandar, Tasriva, additional, Palaniappan, Rajkumar, additional, Ali, Md. Asraf, additional, Rahman, Sam Matiur, additional, and Sundaraj, K., additional

Published
2016
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