Investigation on thermally aged natural ester oil for real‐time monitoring and analysis of transformer insulation

Amalanathan, A. J.; Sarathi, R.; Prakash, Swayam; Mishra, Ashok Kumar; Gautam, Ribhu; Vinu, R.

doi:10.1049/hve.2019.0178

Cited by 35 publications

(20 citation statements)

References 31 publications

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“…Similar results have been inferred in the previous works by the authors on the natural ester fluids [20] and thus, the null hypothesis test towards normal distribution was accepted towards the breakdown characteristics of punga oil. Still now, the breakdown voltage of ester fluid has been investigated without the effect of magnetic field and it was observed to follow a normal distribution with large deviations at the lower and upper percentiles [35].…”

Section: Variation In Breakdown Voltage Of Punga Oil With Magnetic Fieldsupporting

confidence: 89%

“…As per the CIGRE references [19], the electrode size or the needle tip radius for liquid insulation studies can range from 3 to 100 µm with the ground electrode diameter is 50 mm. The gap distance between the needle and ground was maintained as 5 mm to investigate the performance of corona discharges for lower gap spacings and further it can also be compared with the previous research by the authors [16,20] where similar configuration was used for experiments.…”

Section: A High Voltage Source and Sensormentioning

confidence: 99%

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Investigation on Impact of Magnetic Field on the Corona Discharge Activity in Punga Oil Using Fluorescent Fiber and UHF Sensor Techniques

Murugesan¹,

Amalanathan

Sarathi

et al. 2021

IEEE Access

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This paper reports the experimental investigation of the corona discharge activity of punga oil under the influence of a local magnetic field and different voltage profiles (AC and DC voltages) using fluorescent fiber sensor as well as UHF sensor technique. The corona inception voltage (CIV) of punga oil is higher under negative DC voltage followed by positive DC and AC voltage, with a marginal reduction in its CIV magnitude observed on the impact of external magnetic field. The dominant frequency of the UHF signal obtained under AC voltage shifted towards lower frequency (0.6 GHz) with the influence of magnetic flux density to about 85 mT. The rise time, pulse width and energy content of the fluorescent signal formed due to corona activity under AC voltage is found to vary under high magnetic fields confirming the inception results. The fluorescent signals formed due to corona discharge under both AC and DC voltages has its dominant frequency at 1 MHz with no shift observed in the presence of magnetic field. Also, there is no variation in the phase resolved partial discharge (PRPD) pattern observed due to corona discharge (with and without magnetic field) signal using both UHF sensor and the fluorescent sensor. The fluorescent fiber-based technique provides a better accuracy on detecting the corona discharges in punga oil at an early stage compared to conventional UHF sensor. The breakdown voltage of punga oil under different voltage profiles with and without the effect of magnetic field follows normal distribution. The dielectric dissipation factor and electrostatic charging tendency (ECT) of punga oil is observed to be higher than the limit set for insulating fluids towards power transformer operation.INDEX TERMS corona discharge, magnetic field, fluorescent fiber, UHF sensor, rise time, streaming current.

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Section: Variation In Breakdown Voltage Of Punga Oil With Magnetic Fieldsupporting

confidence: 89%

Section: A High Voltage Source and Sensormentioning

confidence: 99%

Investigation on Impact of Magnetic Field on the Corona Discharge Activity in Punga Oil Using Fluorescent Fiber and UHF Sensor Techniques

Murugesan¹,

Amalanathan

Sarathi

et al. 2021

IEEE Access

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“…Insulation oil with advanced insulation and heat dissipation performances are in great demand [21, 22]. The negatively charged nanoparticles generate a local electrical field opposite to the external electric field and reduce the field strength near the cathode [23].…”

Section: Introductionmentioning

confidence: 99%

Exponentially reduced carrier mobility of natural ester via blocking effect of 2D hexagonal boron nitride nanosheets

Huang

et al. 2020

High Voltage

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In this work, the boron nitride (BN) nanosheets were dispersed in natural esters to fabricate the dielectric nanofluid. Microstructures and chemical compositions of the nanosized BN are determined. The stability, viscosity, and thermal conductivity of the BN nanofluid, were obtained. And the dissipation factor, electrical conductivity, and relative permittivity of the BN nanofluid, were measured. The ion mobilities and migrating times of the nanofluid were measured under different volumetric fractions of BN nanosheets and temperatures. Results show that the electrical conductivity and dissipation factor of the nanofluid decreased by 54% and 48% with the addition of only 0.1% of BN nanosheets under 110°C. Both the half‐reduced carrier mobility of the nanofluid and the declined ion concentration by blocking of BN nanosheet contributed to the exponentially reduced electrical conductivity and enhanced dielectric performances of the BN nanofluid. The suppression coefficient k is proposed to quantitatively describe the hinder effect of ion migration in nanofluids by 2D BN nanosheet. Results provide a strategy to design and develop advanced nanofluids with low‐dielectric loss by aids of surface adsorption of ion and steric hindrance of 2D nanosheets.

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“…Amalanathan et al [77] performed turbidity, alternating current (AC) and direct current (DC) impulse and UV absorption spectrum tests on edible natural ester oil and thermally aged ester oil. The study concludes that indeed conditions of the transformer insulation can be monitored in real time using fluorescence analysis.…”

Section: Needle Plane Methodsmentioning

confidence: 99%

Alternative liquid dielectrics in power transformer insulation: a review

Tlhabologo

Samikannu

Mosalaosi

2021

IJEECS

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Transformer liquid dielectrics evolved where mineral oil has been the dominant choice until emergence of synthetic esters and natural esters. Natural ester-based oils have been under extensive investigations to enhance their properties for replacing petroleum-based mineral oil, which is non-biodegradable and has poor dielectric properties. This paper focuses on exposition of natural ester oil application in mixed transformer liquid dielectrics. Physical, chemical, electrical, and ageing characteristics of these dielectrics and the dissolved gas analysis (DGA) were reviewed. Physical properties include viscosity, pour point, flash and fire point which are vital indicators of heat insulation and fire risk. Chemical properties considered are water content, acid number, DGA, corrosive sulphur, and sludge content to limit and detect degradation and corrosion due to oil ageing. Electrical properties including breakdown voltage were considered for consistent insulation during overload and fault conditions. These properties of evolving alternative dielectrics were reviewed based on ASTM International standards and International Electro technical Commission standards for acceptable transformer liquid dielectrics. This review paper was compiled to avail modern methodologies for both the industry and scholars, also providing the significance of using mixed dielectrics for power transformers as they are concluded to show superiority over non-mixed dielectrics.

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Investigation on thermally aged natural ester oil for real‐time monitoring and analysis of transformer insulation

Cited by 35 publications

References 31 publications

Investigation on Impact of Magnetic Field on the Corona Discharge Activity in Punga Oil Using Fluorescent Fiber and UHF Sensor Techniques

Investigation on Impact of Magnetic Field on the Corona Discharge Activity in Punga Oil Using Fluorescent Fiber and UHF Sensor Techniques

Exponentially reduced carrier mobility of natural ester via blocking effect of 2D hexagonal boron nitride nanosheets

Alternative liquid dielectrics in power transformer insulation: a review

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