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153 results on '"Ardila-Rey, Jorge Alfredo"'

3. Assessment of UHF Frequency Range for Failure Classification in Power Transformers.

Author

Schiewaldt, Karl, de Castro, Bruno Albuquerque, Ardila-Rey, Jorge Alfredo, Franchin, Marcelo Nicoletti, Andreoli, André Luiz, and Tenbohlen, Stefan

Subjects
PARTIAL discharges, ELECTRIC arc, DATA acquisition systems, TRANSFORMER insulation, PRINCIPAL components analysis, POWER transformers
Abstract

Ultrahigh-frequency (UHF) sensing is one of the most promising techniques for assessing the quality of power transformer insulation systems due to its capability to identify failures like partial discharges (PDs) by detecting the emitted UHF signals. However, there are still uncertainties regarding the frequency range that should be evaluated in measurements. For example, most publications have stated that UHF emissions range up to 3 GHz. However, a Cigré brochure revealed that the optimal spectrum is between 100 MHz and 1 GHz, and more recently, a study indicated that the optimal frequency range is between 400 MHz and 900 MHz. Since different faults require different maintenance actions, both science and industry have been developing systems that allow for failure-type identification. Hence, it is important to note that bandwidth reduction may impair classification systems, especially those that are frequency-based. This article combines three operational conditions of a power transformer (healthy state, electric arc failure, and partial discharges on bushing) with three different self-organized maps to carry out failure classification: the chromatic technique (CT), principal component analysis (PCA), and the shape analysis clustering technique (SACT). For each case, the frequency content of UHF signals was selected at three frequency bands: the full spectrum, Cigré brochure range, and between 400 MHz and 900 MHz. Therefore, the contributions of this work are to assess how spectrum band limitation may alter failure classification and to evaluate the effectiveness of signal processing methodologies based on the frequency content of UHF signals. Additionally, an advantage of this work is that it does not rely on training as is the case for some machine learning-based methods. The results indicate that the reduced frequency range was not a limiting factor for classifying the state of the operation condition of the power transformer. Therefore, there is the possibility of using lower frequency ranges, such as from 400 MHz to 900 MHz, contributing to the development of less costly data acquisition systems. Additionally, PCA was found to be the most promising technique despite the reduction in frequency band information. [ABSTRACT FROM AUTHOR]

Published
2024
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9. Bioinspired Ultrahigh Frequency Antenna for Partial Discharge Detection in High-Voltage Equipment

Author

Ardila-Rey, Jorge Alfredo, Figueroa Karmelic, Daniel, Pizarro, Francisco, Govindarajan, Suganya, Albuquerque de Castro, Bruno, and Schurch, Roger

Abstract

The detection of partial discharges (PDs) is vital to evaluate the condition of the insulation systems in high-voltage equipment. Although various methods exist to measure the presence of PD, ultrahigh frequency (UHF) approaches have been widely adopted due to their ease of application and their ability to perform measurements without the need for direct galvanic contact with the equipment under test. One of the main challenges with these measurement methods is having sensors with adequate dimensions, bandwidth, and gain, to efficiently measure, in any environment, the electromagnetic (EM) emissions that propagate from the PD pulses even if they are of very low magnitude. This article presents the development of a new bioinspired antenna based on the structural characteristics of the antennae of the Antheraea Polyphemus moth. The bioinspired parameters of the proposed antenna were carefully adjusted to obtain a portable antenna ( $27.4\times 14.4$ cm), with an average gain of 3.07 dBi (between 1.36 and 4.45 dBi) and a bandwidth that covers the entire frequency spectrum, where the most important spectral power contents of PD are emitted (1750 MHz below −10 dB). The results obtained confirm that the proposed antenna is more sensitive than others, such as the Vivaldi antenna or the monopole antenna, commonly used in UHF PD measurements, since it allows accurate temporal and spectral differentiation of the PD pulses, even when the PD is of low magnitude.

Published
2024
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17. New Algorithm Applied to Transformers' Failures Detection Based on Karhunen–Loève Transform

Author

de Castro, Bruno Albuquerque, Binotto, Amanda, Ardila-Rey, Jorge Alfredo, Fraga, Jose Renato Castro Pompeia, Smith, Colin, and Andreoli, Andre Luiz

Abstract

Industry and science have been growing attention to developing systems that ensure the integrity of high voltage devices like power transformers. The goal is to avoid unexpected stoppages by detecting incipient failures before they become a major problem. In this context, the detection of discharge activity is an effective way to assess the condition operation of power transformers since this type of flaw can lead the transformer to total failure. The effectiveness of the fault diagnosis systems is related to their capability to distinguish the types of discharges since different flaws require different maintenance planning. This article proposes a new data analysis, which combined the frequency spectrum of the signals with the Karhunen–Loève Transform to perform self-organization maps. The effectiveness of this analysis was validated by comparing it with the Fundamental Signals Properties Classification Technique, which is widely applied for pattern recognition. Two types of sensing techniques were assessed in order to enhance the capability of the new approach. Results indicated that the new methodology presented lower standard deviation for data classification, being a promising tool to monitoring systems.

Published
2023
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24. Static concentrating photovoltaic modelling using MATLAB

Author

Muhammad-Sukki, Firdaus, primary, Farooq, Haroon, additional, Abu-Bakar, Siti Hawa, additional, Ardila-Rey, Jorge Alfredo, additional, Sellami, Nazmi, additional, Kilpatrick, Ciaran, additional, Muhtazaruddin, Mohd Nabil, additional, Bani, Nurul Aini, additional, and Zulkipli, Muhammad, additional

Published
2021
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26. Mathematical modelling of a static concentrating photovoltaic: simulation and experimental validation

Author

Sukki, Firdaus Muhammad, Farooq, Haroon, Abu-Bakar, Siti Hawa, Ardila-Rey, Jorge Alfredo, Sellami, Nazmi, Kilpatrick, Ciaran, Muhtazaruddin, Mohd Nabil, Bani, Nurul Aini, Zulkipli, Muhammad, Sukki, Firdaus Muhammad, Farooq, Haroon, Abu-Bakar, Siti Hawa, Ardila-Rey, Jorge Alfredo, Sellami, Nazmi, Kilpatrick, Ciaran, Muhtazaruddin, Mohd Nabil, Bani, Nurul Aini, and Zulkipli, Muhammad

Abstract

For the past twenty years, there has been increasing interest and investment in solar photovoltaic (PV) technology. One particular area of interest is the development of concentrating PV (CPV), especially for use in building integration. Many CPV designs have been developed and investigated. This paper aims at producing a mathematical modelling using MATLAB programme to predict the current-voltage (I-V) and power-voltage (P-V) characteristics of a static CPV. The MATLAB programme could also simulate the angular response of the CPV designs-which has never been explored in the previous literature. In this paper, a CPV known as the rotationally asymmetrical dielectric totally internally reflecting concentrator (RADTIRC) was analysed. A specific RADTIRC design that has an acceptance angle of ±40° was investigated in this paper. A mathematical modelling was used to simulate the angular characteristics of the RADTIRC from −50° to 50° with an increment 5°. For any CPV, we propose that the value of opto-electronic gain, Copto-e needs to be included in the mathematical model, which were obtained from experiments. The range of incident angle (±50°) was selected to demonstrate that the RADTIRC is capable of capturing the sun rays within its acceptance angle of ±40°. In each simulation, the I-V and P-V characteristics were produced, and the short circuit current (Isc), the open-circuit voltage (Voc), the maximum power (Pmax), the fill factor (FF) and the opto-electronic gain (Copto-e) were determined and recorded. The results from the simulations were validated via experiments. It was found that the simulation model is able to predict the I-V and P-V characteristics of the RADTIRC as well as its angular response, with the highest error recorded for the Isc, Voc, Pmax, FF and Copto-e was 2.1229%, 5.3913%, 9.9681%, 4.4231% and 0.0000% respectively when compared with the experiment.

Published
2021

27. Indoor Characterisation of a Reverse Truncated Pyramid Concentrator

Author

Tamuno-Ibuomi, Lewis Osikibo, primary, Muhammad-Sukki, Firdaus, additional, Ramirez-Iniguez, Roberto, additional, Ardila-Rey, Jorge Alfredo, additional, Hawa Abu-Bakar, Siti, additional, Bani, Nurul Aini, additional, Hwang See, Chan, additional, Faisal, Nadimul Haque, additional, and Sellami, Nazmi, additional

Published
2021
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32. Effects of urban morphology on microclimate parameters in an urban university campus

Author

Shaikh Salim, Sheikh Ahmad Zaki, Othman, Nurnida Elmira, Wan Ahmad, Siti Wan Syahidah, Mohd Yakub, Mohd Fitri, Muhammad Sukki, Firdaus, Ardila-Rey, Jorge Alfredo, Shahidan, Mohd Fairuz, Mohd Saudi, Ahmad Shakir, Shaikh Salim, Sheikh Ahmad Zaki, Othman, Nurnida Elmira, Wan Ahmad, Siti Wan Syahidah, Mohd Yakub, Mohd Fitri, Muhammad Sukki, Firdaus, Ardila-Rey, Jorge Alfredo, Shahidan, Mohd Fairuz, and Mohd Saudi, Ahmad Shakir

Abstract

This study investigated the effects of urban morphology on microclimate parameters in an urban university campus in Malaysia. Outdoor air temperatures (Tout) were recorded at eight different locations inside the campus for seven days. The study used three urban morphological parameters such as green cover ratio, height-to-width (H/W) ratio, and sky view factor (SVF). The relationship between urban morphological parameters and Tout obtained from in situ measurements was investigated. The results showed that, at a dense green cover ratio of 22% in a 7833 m2 area where the H/W ratio was 0.2, Tout was reduced by about 1% due to a long building shadow cover (12 h) and a high range of SVF (from 0.61 to 0.68). The use of geographic information system (GIS) to generate the spatial data of Universiti Teknologi Malaysia Kuala Lumpur Campus (UTMKL), morphological features and in situ Tout distributions provided useful information of Tout variations, and proved the applicability of GIS as a useful tool in smart city urban planning.

Published
2020

33. Lightning protection methods for wind turbine blades: an alternative approach

Author

Mucsi, Viktor, Ayub, Ahmad Syahrir, Muhammad-Sukki, Firdaus, Zulkipli, Muhammad, Muhtazaruddin, Mohd Nabil, Mohd Saudi, Ahmad Shakir, Ardila-Rey, Jorge Alfredo, Mucsi, Viktor, Ayub, Ahmad Syahrir, Muhammad-Sukki, Firdaus, Zulkipli, Muhammad, Muhtazaruddin, Mohd Nabil, Mohd Saudi, Ahmad Shakir, and Ardila-Rey, Jorge Alfredo

Abstract

Lightning strikes happens in a fraction of time, where they can transfer huge amounts of charge and high currents in a single strike. The chances for a structure to be struck by lightning increases as the height increases; thus, tall structures are more prone to lightning. Despite the existing lightning protection systems available for wind turbine blades, there are still many cases reported due to the fact of damage caused by lightning strike. Owing to that, the present work introduces a new approach for a lightning protection system for wind turbine blades where preliminary investigations were done using Analysis Systems (ANSYS) Workbench. Two models were developed: one with a conventional type down conductor system and the other with a hybrid conductor system. The recorded findings have been compared and discussed, where it was found that the hybrid conductor system may provide alternative protection from lightning for wind turbine blades.

Published
2020

50. Performance Evaluation of Unconcentrated Photovoltaic-Thermoelectric Generator Hybrid System under Tropical Climate

Author

Mohd Shatar, Nursyahirah, Rahman, Mohd Aziz Abdul, Muhtazaruddin, Mohd Nabil, Shaikh Salim, Sheikh Ahmad Zaki, Singh, Baljit, Muhammad-Sukki, Firdaus, Bani, Nural Aini, Saudi, Ahmad Sakir Mohd, Ardila-Rey, Jorge Alfredo, and Bani, Nurul Aini

Subjects
Photovoltaic, Thermoelectric generator, PV-TEG, Sustainable agriculture, Indoor farming
Abstract

Indoor farming is among the approaches which can be adapted to improve agricultural sustainability and ensure the food security of countries. However, adopting indoor farming requires a high amount of energy to sustain the system. Incorporating a renewable energy system for supplying power to agricultural activities will allow the system to be more sustainable in the long run. An unconcentrated photovoltaic-thermoelectric generator (PV-TEG) hybrid system is designed based on the load requirement of an indoor farm. The hybrid system performance under Malaysia’s weather conditions was investigated and analyzed over three months. The designed system has shown its ability to provide sufficient power to the load, as well as supporting an additional load. Besides that, the TEGs power output was found to be dependent on the temperature as well as the types of connections used, where a higher temperature difference and series connection exhibited a better power output. Overall, the combination of the system showed that the addition of a TEG affects the efficiency and power output as compared to a standalone PV. Therefore, this implies that the hybrid system is able to exhibit a more positive outcome in certain weather conditions than a PV standalone system.

Published
2019

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