Article
Computer Science, Information Systems
Rongyan Shang, Changqing Peng, Ruiming Fang
Summary: This study proposed a segmented preprocessing method for the vibration signal of an on-load tap changer (OLTC) to effectively improve fault diagnosis accuracy. Experimental results showed an increase in accuracy from 94.30% to 98.46% with segmented preprocessing, especially for contact wear faults. The method has been successfully applied to actual projects.
Proceedings Paper
Engineering, Electrical & Electronic
Rajaram Shinde, R. Prakash, Alan Sbravati
Summary: On-load tap changers (OLTC) are essential components in power transformers. The use of mineral oil as the dielectric liquid has drawbacks such as high flammability and limited biodegradability. Natural ester liquids have emerged as a viable alternative due to their sustainability, safety, and low coking tendency. Extensive testing has shown that natural ester liquids perform well in OLTCs, making them a suitable replacement for mineral oil. The improved lubricity and reduced coking tendency of natural ester liquids also contribute to the long-term performance of OLTCs.
2022 IEEE 21ST INTERNATIONAL CONFERENCE ON DIELECTRIC LIQUIDS (ICDL)
(2022)
Article
Computer Science, Information Systems
Ali Ahmed Adam Ismail, Humaid Alsuwaidi, A. Elnady
Summary: A voltage regulation scheme using IGBT-based onload tap changer and nonlinear hysteresis control algorithm is proposed in this work. The experimental results demonstrate accurate voltage regulation and the ability to fix voltage sag and swell, but there is a risk of system unavailability due to faults in the drive circuit.
Article
Energy & Fuels
Teresa Nogueira, Jose Carvalho, Jose Magano
Summary: This research compares the effects of ester fluid insulation and mineral oil insulation on power transformers. Ester fluids have advantages in electrical performance, but they increase load-losses, mass, and manufacturing costs. However, ester fluids contribute to improved environmental safety and are an eco-friendly option.
Article
Engineering, Electrical & Electronic
Chong Guo, Qiaogen Zhang, Rui Zhang, Xiaohui He, Zhicheng Wu, Tao Wen
Summary: The study investigates the generation characteristics and mechanism of characteristic gases in transformer oil under strong vibration, as well as illustrates misdiagnosis of insulation status caused by vibration. Increasing vibration pressure leads to higher concentration of characteristic gases.
IET GENERATION TRANSMISSION & DISTRIBUTION
(2022)
Article
Energy & Fuels
Mateusz Cybulski, Piotr Przybylek
Summary: The research analyzed the application of molecular sieves in the drying process of transformer insulation systems, including the study and analysis of water sorption isotherms of various electro-insulating liquids, and the evaluation of the temperature effect on drying dynamics.
Review
Engineering, Electrical & Electronic
Marina N. Lyutikova, Sergey M. Korobeynikov, U. Mohan Rao, Issouf Fofana
Summary: Due to growing environmental concerns, synthetic and natural esters have become the focus for high-voltage equipment insulation in the past two decades. These ester liquids are biodegradable, non-toxic, safe for the environment and human health, and derived from renewable sources with high fire resistance. However, their use is limited in electrical equipment due to factors such as high cost, viscosity and density, electrostatic charge, and faster propagation of streamers in an inhomogeneous electric field. This article presents a comprehensive review on the blend of mineral oil and alternative dielectric fluids, discussing research progress, challenges, and tutorial elements. This is valuable for researchers, utilities, and transformer owners concerned with ester liquids and retrofilling.
IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION
(2022)
Article
Engineering, Electrical & Electronic
Bakhtyar Hoseinzadeh, Frede Blaabjerg
Summary: This paper proposes a new control algorithm for the On-Load Tap Changer (OLTC) of the main transformer in a wind farm, which is responsible for regulating the voltage of the collector network. The algorithm integrates OLTC control into the power plant controller and considers both the transformer voltage and the wind turbine voltages. By adjusting the OLTC voltage setpoint based on the wind turbine voltages, the algorithm prevents the wind turbines from reaching the voltage limits, thereby avoiding equipment stress and generation interruption.
IET GENERATION TRANSMISSION & DISTRIBUTION
(2022)
Article
Engineering, Electrical & Electronic
Adnan Secic, Matej Krpan, Igor Kuzle
Summary: This paper introduces a sound separation methodology based on deep learning neural network for non-invasive audio-based diagnostics, showing higher accuracy compared to Independent Component Analysis. The proposed method can extract useful diagnostic material from both artificial and actual mixtures, and is capable of source separation even from monaural mixtures.
IEEE TRANSACTIONS ON POWER DELIVERY
(2022)
Article
Engineering, Electrical & Electronic
Jose E. Contreras, Josue Rodriguez, Carlos Gaytan
Summary: Currently, the use of new biodegradable dielectric liquids as an alternative to conventional mineral oil in transformers is being considered. However, the higher viscosity of ester liquids compared to mineral oil requires modifications in the impregnation process of insulation materials.
IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION
(2022)
Article
Engineering, Electrical & Electronic
Dawei Feng, Ge Chen, Xiaoyu Yan, Jian Hao, Ruijin Liao
Summary: The study investigates the gas production characteristics of a 3-element mixed insulation oil under thermal fault through simulation and experiments, finding that the gas production of mixed oil is significantly affected by its base oils and generates more H-2 and C2H6 under thermal fault compared to mineral oil. Additionally, the study highlights the differences in gas production between mixed oil and mineral oil, with mixed oil producing higher hydrogen content and other characteristic gases under thermal fault conditions.
Article
Energy & Fuels
Pawel Zukowski, Przemyslaw Rogalski, Tomasz N. Koltunowicz, Konrad Kierczynski, Marek Zenker, Alexander D. Pogrebnjak, Matej Kucera
Summary: This study investigated the conductivity and permittivity of electrical pressboard-insulating liquid-water composites and compared them to water. The presence of water increased the permeability of the composites below 100 Hz, and the conductivity of the composites exponentially increased with increasing water content. The activation energy of the composites' DC conductivity was higher than that of liquid water, and the dielectric relaxation times of the composites were significantly longer than those of water.
Article
Energy & Fuels
Haibin Zhou, Zhicheng Xie, Xing Chen, Qinggang Guan, Jun Deng, Guanwei Liu, Xiaojiang Yan
Summary: This paper investigates the issue of oil flow surging in OLTCs using numerical modeling and experimental methods. The relationship between transition resistance and oil velocity and pressure is analyzed, and optimization suggestions for the protection relay threshold configuration are proposed.
FRONTIERS IN ENERGY RESEARCH
(2022)
Article
Chemistry, Multidisciplinary
Salem Mgammal Al-Ameri, Abdulaziz Almutairi, Muhammad Saufi Kamarudin, Mohd Fairouz Mohd Yousof, Ahmed Abu-Siada, Mohamed Ibrahim Mosaad, Saeed Alyami
Summary: This paper explores the application of frequency response analysis (FRA) technique in detecting transformer tap changer faults, with experimental verification of two common tap changer faults. An electrical equivalent circuit model is proposed for better understanding of tap changer fault mechanisms. Simulation and implementation of the equivalent circuits are conducted using Simulink and MATLAB\R2018a.
APPLIED SCIENCES-BASEL
(2021)
Article
Engineering, Electrical & Electronic
Andres Montero, Belen Garcia, Juan Carlos Cabanelas
Summary: This article proposes a new experimental methodology to quantify the ratio of mineral oil in natural esters, which is vital for assessing the impact of remaining mineral oil on the flash and fire point of the ester, as well as transformer dielectric performance.
IEEE ELECTRICAL INSULATION MAGAZINE
(2023)
