Article
Energy & Fuels
Beki Sekongo, Stephan Brettschneider, U. Mohan Rao, Issouf Fofana, Marouane Jabbari, Patrick Picher, Zie Yeo
Summary: This article investigates the breakdown behavior of ester fluids under prolonged usage conditions and evaluates important characteristics. It is found that ester liquids generally perform better than mineral oil in many cases. Additionally, the radius of curvature and thermal aging have an impact on the performance of ester fluids.
Article
Multidisciplinary Sciences
Jean Lambert Jiosseu, Asse Jean-Bernard, Ghislain Mengata Mengounou, Adolphe Moukengue Imano, Emeric Tchamdjio Nkouetcha
Summary: This article presents a comparative study on the physicochemical and electrical properties of monoesters of castor oil and their counterparts based on FeO3 and Z(n)O nanoparticles. Results are compared with those of triesters and the IEEE C 57.14 standard. Statistical analysis indicates an increase in viscosity and acid number for both FeO3 and Z(n)O samples. Fire point shows an increment for FeO3 samples, while a regression is observed for Z(n)O samples. Breakdown voltage and partial discharge inception voltage show improvements with FeO3 samples.
SCIENTIFIC REPORTS
(2023)
Article
Chemistry, Analytical
Sayed A. Ward, Adel El-Faraskoury, Mohamed Badawi, Shimaa A. Ibrahim, Karar Mahmoud, Matti Lehtonen, Mohamed M. F. Darwish
Summary: Integration of various techniques in dissolved gas analysis (DGA) improves fault monitoring and demonstrates the importance of using different diagnostic methods for power transformers. Experimental setup and results from the Egyptian Electricity Transmission Company (EETC) support the effectiveness of combining techniques for precise interpretation of transformer conditions.
Article
Engineering, Electrical & Electronic
Josue Rodriguez, Jose Contreras, Carlos Gaytan
Summary: This study evaluates the gas generation of a new soybean-based natural ester liquid in distribution and power transformers through lab-scale testing, and discusses predicting transformer fault types using different diagnostic methods. Results show that overheating issues in natural esters are associated with ethylene, while high energy faults and partial discharge faults are linked to acetylene and hydrogen, respectively. The Duval triangle method is confirmed as the most reliable approach for diagnosing natural ester liquids.
IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION
(2021)
Review
Chemistry, Multidisciplinary
Zulbirri Faizol, Farid Zubir, Norhafezaidi Mat Saman, Mohd Hafizi Ahmad, Mohamad Kamal A. Rahim, Osman Ayop, Muzammil Jusoh, Huda A. Majid, Zubaida Yusoff
Summary: This article reviews the current methods for detecting and locating partial discharge signals in high-voltage equipment, compares their efficacy, and summarizes the future direction of research in PD detection.
APPLIED SCIENCES-BASEL
(2023)
Article
Chemistry, Physical
Milos Sarpataky, Juraj Kurimsky, Michal Rajnak, Katarina Paulovicova, Michal Krbal, Ludek Pelikan
Summary: This study presents an experimental comparison of AC breakdown voltage in natural and synthetic ester-based nanofluids with fullerene and magnetite nanoparticles. Statistical analysis shows that the AC BDV of nanofluids increases with increasing cumulative probability. Fullerene nanoparticles tend to reduce AC BDV in natural ester, while magnetic nanoparticles enhance AC BDV in both esters, though to a different extent.
JOURNAL OF MOLECULAR LIQUIDS
(2022)
Article
Engineering, Electrical & Electronic
Boseong Seo, Jaekyung Shin, Taejin Kim, Byeng D. Youn
Summary: With the expansion of the energy market, ensuring the safe and stable operation of the electrical power system has become a crucial issue. In this research, a method called the iterative denoising autoencoder (IDAE) is proposed to exploit valuable transformer data by imputing missing values of dissolved gas analysis (DGA) data. The proposed method accurately diagnoses the health state of transformers by estimating the missing values of DGA data. Case studies on field data provided by an electric power corporation verify the effectiveness of the proposed method for imputing missing DGA data.
ELECTRIC POWER SYSTEMS RESEARCH
(2022)
Review
Computer Science, Information Systems
Md Rashid Hussain, Shady S. Refaat, Haitham Abu-Rub
Summary: This paper reviews and evaluates the current state-of-the-art methods for partial discharge detection and localization in power transformers, highlighting detailed comparisons and discussions on the drawbacks and challenges of different detection techniques. Additionally, it briefly addresses PD denoising signals, feature extraction of PD signals, and classification of partial discharge sources.
Article
Automation & Control Systems
Jun Jia, Chengbo Hu, Qiang Yang, Yuncai Lu, Bo Wang, Hengyang Zhao
Summary: The article presents an algorithmic solution based on the time difference of arrival algorithm and semidefinite relaxation convex optimization to improve the accuracy of PD source localization. It fully considers the refraction and diffraction errors, measurement errors, and their relationship in the process of PD signal propagation. The proposed solution outperforms existing algorithms with a localization error of about 0.1 m, as confirmed through simulation, testbed, and field experiments.
IEEE TRANSACTIONS ON INDUSTRIAL INFORMATICS
(2021)
Article
Energy & Fuels
Jiaxin Liu, Zijian Zhao, Yuanchen Zhong, Chenchen Zhao, Guogang Zhang
Summary: This paper presents a time series forecasting model based on the SARIMA model to predict the dissolved gas concentration in power transformer oil. The SARIMA model shows the most accurate and stable performance in predicting the trend component of the gas, and considering external factors improves the accuracy of the predictions.
Article
Engineering, Electrical & Electronic
Mohammad Amin Jangjoo, Mehdi Allahbakhshi, Hassan Reza Mirzaei
Summary: Partial discharge (PD) localization in power transformers using the ultra-high frequency (UHF) technique based on time difference of arrival equations is advanced. By receiving and processing PD electromagnetic waves (EMWs) through installed sensors on the tank, the PD location can be estimated. The UHF method for localization accuracy is affected by non-line of sight propagation, EMW reflection and refraction, and arrival time detection error. This study proposes a new method using the distance between hyperbolic surfaces to determine optimal sensor installation positions on the tank.
ELECTRIC POWER SYSTEMS RESEARCH
(2023)
Article
Energy & Fuels
Nitchamon Poonnoy, Cattareeya Suwanasri, Thanapong Suwanasri
Summary: This research focuses on identifying faults in power transformers during operation using dissolved gas analysis and fuzzy logic methods. Key gas, IEC ratio, and Duval triangle techniques are utilized to evaluate the condition of the transformer, with recommendations for maintenance strategies proposed.
Article
Engineering, Electrical & Electronic
Sungho Yoon, Hyeongwook Son, Woobin Kim, Dongzoon Lee, Jeongtae Kim
Summary: This paper investigates the creepage discharge process in moisture-absorbed pressboard under AC voltage stress. Measurement for partial discharges, dissolved gases, and furan compounds was carried out on various types of specimens. The results showed that the presence of moisture in the specimens led to an increase in partial discharge inception voltage, discharge number, and accumulated charge quantity, while the discharge magnitude per pulse decreased. Different partial discharge patterns were observed at the initial stage, but all cases exhibited a recurrence pattern of large/small discharges followed by small discharges. Gas generation was found to be lower in dry pressboard with moisture in oil compared to normal dry specimens, but a significant amount of furans was produced. In contrast, wet pressboard generated a large amount of gas but almost no furans. The results suggest that moisture aggregation in the amorphous region of pressboard leads to discharge attraction and accelerates the degradation and carbonization of pressboards.
JOURNAL OF ELECTRICAL ENGINEERING & TECHNOLOGY
(2023)
Article
Engineering, Multidisciplinary
Walid S. S. Salah, Ahmed H. H. Gad, Mahmoud A. A. Attia, Soliman M. M. Eldebeikey, Abdelhady R. R. Salama
Summary: This research presents a design for a compact double layer printed UHF antenna to detect and discriminate various types of PD activity in a power transformer. The designed antenna has a small/simple size and ultra-wide frequency passband, making it suitable for detecting different types of PD activity in power transformers.
AIN SHAMS ENGINEERING JOURNAL
(2022)
Article
Engineering, Electrical & Electronic
Hanbo Zheng, Yang Hang, Yongji Feng, Xufan Li, Qingjun Peng
Summary: Natural ester is a potential alternative to mineral oil with high degradability, but its inferior breakdown characteristics hinder its application in large power equipment. This research investigates the breakdown characteristics of natural ester through calculations and model development. The results show that the natural ester has a similar breakdown voltage but a lower acceleration voltage compared to mineral oil. The model also considers the effect of temperature on carrier mobility.
IEEJ TRANSACTIONS ON ELECTRICAL AND ELECTRONIC ENGINEERING
(2023)
Article
Thermodynamics
Xiang Zhang, Muhammad Daghrah, Zhongdong Wang, Qiang Liu
APPLIED THERMAL ENGINEERING
(2020)
Article
Physics, Multidisciplinary
Hanwen Ren, Qingmin Li, Chengqian Li, Haoyu Gao, Zhongdong Wang
Article
Engineering, Electrical & Electronic
Hanwen Ren, Qingmin Li, Zhongdong Wang
IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT
(2020)
Article
Physics, Fluids & Plasmas
Xuwei Huang, Zi'an Ding, Tao Liu, Qingmin Li, Zhongdong Wang
PLASMA SCIENCE & TECHNOLOGY
(2020)
Article
Engineering, Electrical & Electronic
Xiaozhou Mao, Zhongdong Wang, Peter Crossley, Paul Jarman, Andrew Fieldsend-Roxborough, Gordon Wilson
Article
Engineering, Electrical & Electronic
Lujia Wang, Xiang Zhang, Rafael Villarroel, Qiang Liu, Zhongdong Wang, Lijun Zhou
IET GENERATION TRANSMISSION & DISTRIBUTION
(2020)
Article
Physics, Applied
Donglin Liu, Qiang Liu, Zhongdong Wang
Summary: Understanding the pre-breakdown phenomenon in dielectric liquids, known as streamers, is crucial for the application of liquids in high voltage and power dense devices. The stable propagation velocity of the second mode streamer is a key characteristic, with recent research showing that limiting the electron saturation velocity can greatly impact the streamer propagation velocity.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2021)
Article
Engineering, Electrical & Electronic
Hanwen Ren, Haoyu Gao, Chengqian Li, Qingmin Li, Zhongdong Wang
Summary: This paper investigates the effect of different voltage types on the space charge characteristics inside solid insulation, revealing that the charge amount is mainly determined by input power and the injected charge depth is shallow. Results under unipolar conditions are frequency-independent, while charge amount under bipolar conditions is negatively correlated with frequency.
IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION
(2021)
Article
Engineering, Electrical & Electronic
Hanwen Ren, Yasuhiro Tanaka, Hiroaki Miyake, Kazuki Endo, Qingmin Li, Haoyu Gao, Chengqian Li, Zhongdong Wang
Summary: Pulse wave voltages result in more accumulation of positive charge inside polyimide compared to DC voltages, with higher space charge under negative voltages above 50 Hz and most distortion under negative voltage at 500 Hz. The distribution of accumulated charge tends to stabilize when the duty ratio exceeds 50%.
IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION
(2021)
Article
Engineering, Electrical & Electronic
Shuhang Shen, Qiang Liu, Zhongdong Wang
Summary: The experimental study focused on analyzing the spatial characteristics of Mach-cone shaped shockwaves generated by streamers in mineral oil and synthetic ester. The results showed that the appearance of Mach-cone shaped shockwave is an effective indicator of actively propagating streamer channel. Voltage levels did not have a significant impact on the observed shockwave parameters.
IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION
(2021)
Article
Engineering, Electrical & Electronic
Hanwen Ren, Yasuhiro Tanaka, Hiroaki Miyake, Qingmin Li, Haoyu Gao, Chengqian Li, Zhongdong Wang
Summary: The study investigated charge phenomena under sine and half-wave sine voltages within the frequency range of 500 Hz. Experimental results showed that the amount of accumulated charge depends on the voltage's waveform and frequency parameters, with lower frequency conditions resulting in more charge accumulation.
Article
Engineering, Electrical & Electronic
Hanwen Ren, Qingmin Li, Haoyu Gao, Chengqian Li, Sihong Cheng, Zhongdong Wang
Summary: The proposed optical method for space charge measurement, based on ellipsometry detection principle and the photoelastic effect of the sensor, shows potential in providing high signal-to-noise ratio, terahertz bandwidth, and nanometer spatial resolution. The mathematical relationship derived indicates that the light intensity difference measured can linearly represent the elastic force generated from space charge. The built ellipsometry detection system demonstrates fast measurement speed and accurate tracking of elastic waves, confirming the feasibility and effectiveness of the proposed method.
IEEE SENSORS JOURNAL
(2021)
Article
Engineering, Electrical & Electronic
Haichuan Yu, Shuhang Shen, Qiang Liu, Zhongdong Wang
Summary: The uniformity of electric field has a significant impact on the breakdown mechanisms of dielectric liquids. This study identifies and quantifies the transition field factor boundary between streamer initiation and propagation mechanisms. Different methods are introduced and applied to derive the transition field factor boundaries for mineral oil under positive and negative lightning impulses. The results suggest that the negative transition field factor boundary is lower than the positive one, indicating a polarity-dependent effect on breakdown mechanisms.
IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION
(2021)
Article
Polymer Science
Hanwen Ren, Qingmin Li, Yasuhiro Tanaka, Hiroaki Miyake, Haoyu Gao, Zhongdong Wang
Summary: The study investigates the space charge phenomena of a solid polymer under thermal and electrical stresses with different frequencies and waveforms, providing insights into the characteristics of charge accumulation under different voltage and temperature conditions.
Article
Engineering, Electrical & Electronic
ShengJi Tee, Qiang Liu, Zhongdong Wang, Fikri Hafid, Pierre Tournet
Summary: Asset management of instrument transformers (ITs) has been gaining attention, and this study investigates failure causes of a family of combined measuring ITs through temperature profile simulations and consideration of moisture migration behavior in an oil-impregnated paper insulation system. It is found that temperature differences and relative saturation hysteresis during summer could lead to lower dielectric strength and failures, while factors such as in-service age, operating voltage level, and environment also influence failure rate.