scholarly journals The Correlation of Transformer Oil Electrical Properties with Water Content Using a Regression Approach

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2089
Author(s):  
Sifeddine Abdi ◽  
Noureddine Harid ◽  
Leila Safiddine ◽  
Ahmed Boubakeur ◽  
Abderrahmane (Manu) Haddad
Keyword(s):  
Regression Analysis ◽  
Electrical Properties ◽  
Water Content ◽  
Breakdown Voltage ◽  
Mobile Station ◽  
Dissipation Factor ◽  
Exponential Model ◽  
Transformer Oil ◽  
The Impact ◽  
Dielectric Dissipation Factor

An experimental investigation is conducted to measure and correlate the impact of the water content on the electrical characteristics of the mineral oil for transformers, particularly the breakdown voltage, the resistivity, and the dielectric dissipation factor. Regression method is carried out to compare the results obtained through laboratory experiments with those predicted using an analytical model. A treatment to reduce water content in oil involving filtration, degassing and dehydration using a SESCO mobile station was applied to the new, regenerated, and used oil samples in service. The breakdown voltage, the resistivity, and the dielectric dissipation factor of the samples were measured. Regression analysis using an exponential model was applied to examine the samples electrical properties. The results show that, after treatment, the breakdown voltage and resistivity increase as the water content decreases, unlike the dielectric dissipation factor which exhibits a decreasing trend. This trend is found to be similar for the three oil samples: new, regenerated, and used. The results of the regression analysis give close agreement with the experimental results for all the samples and all studied characteristics. The model shows strong correlation with high coefficients (>90%).

scholarly journals Photoluminescence Spectroscopy Measurements for Effective Condition Assessment of Transformer Insulating Oil

Processes ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 732
Author(s):  
Abdelrahman M. Alshehawy ◽  
Diaa-Eldin A. Mansour ◽  
Mohsen Ghali ◽  
Matti Lehtonen ◽  
Mohamed M. F. Darwish
Keyword(s):  
Electronic States ◽  
Dissipation Factor ◽  
Condition Assessment ◽  
Transformer Oil ◽  
Term Operation ◽  
Pl Spectra ◽  
Insulating Oil ◽  
Vis Spectroscopy ◽  
Effective Condition ◽  
Dielectric Dissipation Factor

Condition assessment of insulating oil is crucial for the reliable long-term operation of power equipment, especially power transformers. Under thermal aging, critical degradation in oil properties, including chemical, physical, and dielectric properties, occurs due to the generation of aging byproducts. Ultraviolet-visible (UV-Vis) spectroscopy was recently proposed for the condition assessment of mineral oil. However, this absorption technique may involve all electronic states of the investigated material which typically yield a broad spectrum, and thus cannot precisely reflect the electronic structure of aged oil samples. It also cannot be implemented as an online sensor of oil degradation. In this paper, photoluminescence (PL) spectroscopy is introduced, for the first time, for effective condition assessment of insulating oil. The PL technique involves emission processes that only occur between a narrow band of electronic states that are occupied by thermalized electrons and consequently yields a spectrum that is much narrower than that of the absorption spectrum. Aged oil samples with different aging extents were prepared in the laboratory using accelerated aging tests at 120 °C, under which 1 day of laboratory aging is equivalent to approximately 1 year of aging in the field. These aged samples were then tested using PL spectroscopy with a wavelength ranging from 150 nm to 1500 nm. Two main parameters were evaluated for quantitative analysis of PL spectra: The full width at half-maximum and the enclosed area under the PL spectra. These parameters were correlated to the aging extent. In conjunction with PL spectroscopy, the aged oil samples were tested for the dielectric dissipation factor as an indication of the number of aging byproducts. Interestingly, we find a correlation between the PL spectra and the dielectric dissipation factor. The results of PL spectroscopy were compared to those of UV-Vis spectroscopy for the same samples and the parameters extracted from PL spectra were compared to the aging b-products extracted from UV-Vis spectra. Finally, the corresponding physical mechanisms were discussed considering the obtained results and the spectral shift for each spectrum. It was proved that PL spectroscopy is a promising technique for the condition assessment of insulating oil when compared to conventional transformer oil assessment measuring techniques and even to other optical absorption techniques.

Effect of Water on Electrical Properties of Refined, Bleached, and Deodorized Palm Oil (RBDPO) as Electrical Insulating Material

2013 ◽  
Vol 64 (4) ◽  
Author(s):  
Nazera Ismail ◽  
Yanuar Z. Arief ◽  
Zuraimy Adzis ◽  
Shakira A. Azli ◽  
Abdul Azim A. Jamil ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Breakdown Voltage ◽  
Palm Oil ◽  
Pour Point ◽  
Electrical Breakdown ◽  
Dissipation Factor ◽  
Mineral Oil ◽  
Flash Point ◽  
Effect Of Water ◽  
Insulating Liquid

This paper describes the properties of refined, bleached, deodorized palm oil (RBDPO) as having the potential to be used as insulating liquid. There are several important properties such as electrical breakdown, dielectric dissipation factor, specific gravity, flash point, viscosity and pour point of RBDPO that was measured and compared to commercial mineral oil which is largely in current use as insulating liquid in power transformers. Experimental results of the electrical properties revealed that the average breakdown voltage of the RBDPO sample, without the addition of water at room temperature, is 13.368 kV. The result also revealed that due to effect of water, the breakdown voltage is lower than that of commercial mineral oil (Hyrax). However, the flash point and the pour point of RBDPO is very high compared to mineral oil thus giving it advantageous possibility to be used safely as insulating liquid. The results showed that RBDPO is greatly influenced by water, causing the breakdown voltage to decrease and the dissipation factor to increase; this is attributable to the high amounts of dissolved water.

scholarly journals A mechanistic model for electrical conduction in soil–root continuum: a virtual rhizotron study

2018 ◽  
Author(s):  
Sathyanarayan Rao ◽  
Félicien Meunier ◽  
Solomon Ehosioke ◽  
Nolwenn Lesparre ◽  
Andreas Kemna ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Electrical Properties ◽  
Root Growth ◽  
Water Content ◽  
Soil Water ◽  
Water Uptake ◽  
Numerical Study ◽  
Root Segments ◽  
Bulk Electrical Conductivity ◽  
The Impact

Abstract. Electrical Resistivity Tomography (ERT) has become an important tool to study soil water fluxes in cropped field. ERT results translates to water content via empirical pedophysical relations that take soil physical properties into account, usually ignoring the impact of roots. Studies shows high root dense soils behaves quite differently than less root dense soils in terms of bulk electrical conductivity. Yet, we do not completely understand the impact of root segments on the ERT measurements. In this numerical study, we coupled an electrical model with a plant-soil water flow model to investigate the impact of plant root growth and water uptake on the ERT virtual experiment. The electrical properties of roots were explicitly accounted in the finite element mesh and we obtained the electrical conductivities of root segments by conducting specific experiments on real maize plants. The contrast between electrical conductivity of roots and soil depends on factors such as root density, irrigation, root age, and root water uptake pattern. Root growth and water uptake processes thus affect this contrast together with the soil electrical properties. Model results indicate a non-negligible anisotropy in bulk electrical conductivity induced by root processes. We see a greater anisotropy in a sandy medium when compared to a loamy medium. We find that the water uptake process dominates the bulk electrical properties. The Gauss-Newton type ERT inversion of virtual rhizotron data demonstrate that, when root-soil electrical conductivity contrasts are high, it can lead to error in water content estimates since the electrical conductivity is partly due to root. Thus, incorporating the impact of root in the pedophysical relations is very important to interpret ERT results directly as water content.

Evaluation of Breakdown Voltage and Water Content in Transformer Oil Using Multi Frequency Ultrasonic and Generalized Regression Neural Network

2021 ◽  
Vol 16 (3) ◽  
pp. 387-394
Author(s):  
Yang Su ◽  
Ming-Hui Liu ◽  
Xu-Hui Kong ◽  
Chen-Jun Guo ◽  
Jiang Zhu ◽  
...  
Keyword(s):  
Neural Network ◽  
Water Content ◽  
Breakdown Voltage ◽  
Power Transformer ◽  
Oil Quality ◽  
Transformer Oil ◽  
Generalized Regression Neural Network ◽  
Test Sets ◽  
Generalized Regression ◽  
Training Sets

Power transformer is regarded as one of the crucial part of electrical power transmission and distribution system. The quality of transformer oil can directly affect the operation of the power transformer, and breakdown voltage (BDV) and water content are the two main parameters of transformer oil quality. Monitoring the BDV and water content of transformer oil is considered as an important method to evaluate the safe operation of power systems. This work proposes the measurement of BDV and water content in transformer oil using multi frequency ultrasonic and generalized regression neural network (GRNN). The BDV and water content of all 210 samples were firstly tested according to the traditional testing methods and the multi frequency ultra-sonic technology, separately. And then the 210 samples were randomly divided into training sets and test sets. The obtained multi frequency ultrasonic data were set as the input of GRNN, and the BDV and water content as the output of GRNN. Moreover, the 20-fold-cross-validation was incorporated to obtain the best smoothing factor δ for GRNN. Finally, the GRNN model was trained by the training sets with δ =4.54 and was evaluated with the test sets. All results show that the lower BDV or the higher water content of the sample will cause greater ultrasonic sound attenuation, and the prediction accuracy of the prediction model for BDV and water con-tent in oil is up to 95%. It provides a new method for evaluating the health of transformer oil.

Effects of YMnO3 Addition on Phase Structure, Microstructure and Electrical Properties of (Na0.515K0.485)0.94Li0.06(Nb0.8Ta0.2)O3 Lead-Free Ceramics

2014 ◽  
Vol 979 ◽  
pp. 167-170
Author(s):  
Pornsuda Bomlai
Keyword(s):  
Grain Size ◽  
Electrical Properties ◽  
Phase Structure ◽  
Dissipation Factor ◽  
Lead Free ◽  
Low Dielectric ◽  
Lead Free Ceramics ◽  
Dielectric Dissipation Factor ◽  
Sintering Method ◽  
Piezoelectric Devices

The (1-x)[(Na0.515K0.485)0.94Li0.06(Nb0.8Ta0.2)O3]-xYMnO3 (x = 0, 0.005, 0.01, 0.015 and 0.02) lead-free ceramics were synthesized by solid-state reaction sintering method. It was found that the addition of YMnO3 affected on the grain size, phase structure and electrical properties of (Na0.515K0.485)0.94Li0.06(Nb0.8Ta0.2)O3 ceramics. The grain size decreased with increasing YMnO3 content (x ≥ 0.01) and led to poor densification. The ceramic doped with 0.5 mol% YMnO3 showed good electrical properties such as d33 = 195 pC/N, kp = 43.9 %, Tc = 292 °C, TO−T = 35 °C, εr = 820 and rather low dielectric dissipation factor = 2.1%. This indicates that 0.5 mol% YMnO3 -doped (Na0.515K0.485)0.94Li0.06(Nb0.8Ta0.2)O3 piezoceramic is an alternative lead-free piezoelectric material for the development of piezoelectric devices working at high temperature.

scholarly journals Study Concerning the Influence of the Grinding Percentage on Some Electrical Properties of PA 6.6, POM and ABS by Methods for Determining Relative Permittivity and the Dielectric Dissipation Factor

2017 ◽  
Vol 54 (3) ◽  
pp. 453-460 ◽  
Author(s):  
Ovidiu Constantin Novac ◽  
Gheorghe Radu Emil Maries ◽  
Dan Chira ◽  
Mihaela Novac
Keyword(s):  
Electrical Properties ◽  
Relative Permittivity ◽  
Acrylonitrile Butadiene Styrene ◽  
Dissipation Factor ◽  
Measurement Frequency ◽  
New Material ◽  
Polyamide 6.6 ◽  
Dielectric Dissipation Factor ◽  
Butadiene Styrene

This paper presents the influence of the grinding percentage on some electrical properties, when the process of injection is used in the production of technical commodities, made of polyamide 6.6 (PA 6.6), polyoxymethylene (POM) and acrylonitrile butadiene styrene (ABS), for different industries. The specimens produced had the following compositions: new material 100%, new material 80% + grinding 20%, new material 60% + grinding 40%, new material 40% + grinding 60%, new material 20% + grinding 80% and 100% grinding. The measurement of the electrical properties was carried out using the methods for the determination of relative permittivity and of the dielectric dissipation factor, with the method of zero by Schering bridge. It was found that increasing the percentage of grinding in samples, from 0% to 100%, determined a slight increase in the values of relative permittivity at all three polymers tested and the increase of measurement frequencies for acrylonitrile butadiene styrene and polyoxymethylene led to insignificant changes in the values of relative permittivity, while in the case of polyamide, increasing the measurement frequency led to a slight decrease in the values of relative permittivity. It was also found that increasing the proportion of grinding in the specimens, from 0% to 100%, determined a slight increase in the values of the dielectric dissipation factor in the case of polyamide and polyoxymethylene, while in the case of acrylonitrile butadiene styrene increasing the percentage of grinding in the samples resulted in insignificant changes. The increase in the measurement frequencies for the three tested polymers resulted in a decrease in the values of the dielectric dissipation factor.

Investigation on the Dielectric Properties of Palm Oil with Silicon Carbide Doping for Transformer Application

2021 ◽  
Vol 317 ◽  
pp. 377-382
Author(s):  
Muhamad Faiz Md Din ◽  
Nurul Sofea Mazlan ◽  
ABDUL RASHID BIN ABDUL RAHMAN ◽  
Mohd Taufiq Jusoh ◽  
Nur Sabrina Suhaimi ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Breakdown Voltage ◽  
Palm Oil ◽  
Dielectric Strength ◽  
Dissipation Factor ◽  
Electrode Gap ◽  
Insulating Liquids ◽  
Transformer Oils ◽  
Tan Δ ◽  
Dielectric Dissipation Factor

The dielectric strength of insulating liquids of transformer acts an important parameter in the operation of transformer. Thus, great interest and many studies have been extensively done to improve the dielectric strength. One of study is the introduction of nanoparticle in the transformer oils. Study of the nanoparticles for the last few years had been found that, it can be dispersed in the transformers oils to be nanofluids and directly enhance the transformer performance. In this study, an investigation has been carried out to focus on the effect of silicon carbide (SiC) nanoparticle to AC (alternating current) breakdown voltage of the Refined, Bleached, and Deodorized Palm Oil (RBDPO). AC breakdown test have been conduct according to the standard of the IEC 60156. Besides that, a number of parameters will be evaluated such as dielectric dissipation factor (tan δ), relative permittivity (ε), and resistivity (ρ). Based on the results of the experiment, the electrode gap at 2.5 mm having the highest AC breakdown voltage compared to the other electrode gap which are 1.0 mm, 1.5 mm and 2.0 mm. Furthermore, doping with different concentrations of the silicon carbide (SiC) in Refined, Bleached, and Deodorized Palm Oil (RBDPO) found decreasing of AC breakdown voltage from 52.09 kV (without SiC) to 45.3 kV for 0.001 g/L, 43.2 kV for 0.003 g/L and 40.1 kV for 0.005 g/L respectively.

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