An apparatus for simplifying titration in a controlled atmosphere. Application to the determination of moisture in transformer oil with Fischer reagent

The theoretical foundations of changes in the transformer oil quality characteristics, depending on the aging degree, are presented. The introduction of a new indicator of the exploitational transformer oils quality – “stability against oxidation” – is substantiated as a way of solving the scientific and technical problem of assessing the resource characteristics of a transformer insulating system. In order to select the best measures to maintain the quality of power transformers insulating oils, a newly developed “Method for the Experimental Determination of the Luquid Dielectric Resource and Measures for its Restoration” is presented.

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The Determination of Kinetic Parameters of Transformer Oil and its Blends by Thermal Analysis

ENERGYO ◽

10.1515/energyo.0034.00133 ◽

2018 ◽

Author(s):

Veresha Dukhi ◽

Ajay Bissessur ◽

Catherine Jane Ngila ◽

Nelson Mutatina Ijumba

Keyword(s):

Thermal Analysis ◽

Kinetic Parameters ◽

Transformer Oil

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Research Progress for Determination of the Antioxidant Content in Transformer Oil

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.543-547.1157 ◽

2014 ◽

Vol 543-547 ◽

pp. 1157-1160 ◽

Cited By ~ 1

Author(s):

Chen Yao Liu ◽

Na Na Wang ◽

Yun Guang Huang ◽

Wei Wei Yu ◽

Li Ping Zhu ◽

...

Keyword(s):

Oxidation Process ◽

Oxidation Stability ◽

Development Trend ◽

Electric Arc ◽

Transformer Oil ◽

Research Progress ◽

Oil Oxidation ◽

Electrochemical Test ◽

The Development Trend

Under the actions of dissolved oxygen, temperature, electric field, electric arc, moisture, impurities and metal catalysts, transformer oil in operation will undergo oxidation and cracking, which may result in production of large quantities of peroxides, alcohols, aldehydes, ketones and acids. To improve the oxidation stability of oil, the antioxidants should be added into the transformer oil before operation. This paper mainly introduced the oxidation process of transformer oil, the harm of transformer oil oxidation and the method for the determination of the T501 antioxidants content in transformer oil. It also forecast the development trend of the electrochemical test in the determination of T501 antioxidants content.

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Validation of an improved European standard method for the determination of PCBs in oil samples

Nova Biotechnologica et Chimica ◽

10.36547/nbc.1133 ◽

2021 ◽

Vol 9 (3) ◽

Author(s):

Zdenka Cencič Kodba ◽

Darinka Brodnjak Vončina

Keyword(s):

Transformer Oil ◽

Gas Chromatograph ◽

European Standard ◽

Internal Standards ◽

Standard Methods ◽

Average Recovery ◽

Mineral Oils ◽

Waste Oils ◽

Analytical System

Two European standard methods (EN 12766 and EN 61619) are currently used for the determination of PCBs in specific oil matrix. However, apolar matrix compounds (e.g. hydrocarbons) elute from the adsorbent together with the PCBs and are injected into the analytical system where their presence contaminates the inlet, detectors and columns; and decreases system performances. Insufficient cleanup causes delay of elution of PCBs from GC columns. By using new sulfoxide-bonded silica, PCBs are better separated from aliphatic hydrocarbons because the specificity of the stationary phase for these compounds is much higher that that used in both standard methods. A gas chromatograph AT6890 with two capillary columns of different polarities (HP-5MS and DB-1701) coupled to two μECDs is used. Oven temperature program is as followed: 90°C (1 min), 70°C/min to 180°C, 5°C/min to 230°C (0.1 min), 1.5°C/min to 280°C. Run time is 46 min. The procedure was validated through regular analysis of blanks, fortified samples (transformer oil, motor used and unused oil) and certified materials (BCR-449 and BCR-420, waste mineral oils, high and low PCB levels). Two internal standards were used (PCB 30 and PCB 209). An average recovery ± RSD of 82.8 ± 5.4 % was achieved for all six PCBs in different matrices. The LOQ per single PCB congener is 0.2 mg kg-1. The average recovery ± RSD for the BCR-420 is 92.0 ± 4.6 % and for the BCR-449 is 105 ± 2.5 % for all certified PCBs in waste oils.

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Effects of pre- and postharvest factors on browning in Braeburn

Horticultural Science ◽

10.17221/180/2013-hortsci ◽

2014 ◽

Vol 41 (No. 1) ◽

pp. 19-26 ◽

Cited By ~ 8

Author(s):

D. Hatoum ◽

K. Buts ◽

M.L.A.T.M. Hertog ◽

A.H. Geeraerd ◽

A. Schenk ◽

...

Keyword(s):

Experimental Design ◽

Storage Time ◽

Growing Season ◽

Controlled Atmosphere ◽

Storage Duration ◽

Growing Seasons ◽

And Storage

The effects of several pre- and postharvest factors on apple cv. Braeburn browning disorder (BBD) incidence using a nine-factor experimental design has been investigated. The design allowed the determination of the effects of single factors as well as their interaction with growing season and storage time. BBD increased in severity with storage duration. BBD incidence was reduced with calcium and potassium fertilizers application, while it was increased when triazoles were used. Delayed controlled atmosphere (DCA) application resulted in less BBD in storage, while treatment with 1-methylcyclopropene (1-MCP) increased BBD incidence. More BBD was observed in fruit stored at above optimal CO<sub>2 </sub>levels. BBD incidence was increased when O<sub>2</sub> concentration in CA was increased from 1 kPa to 3 kPa (optimum CA) or 6 kPa. Finally, the various factors showed a different effect for different growing seasons and storage time. These findings suggest a possible mechanism for the development of BBD. Further work should focus on extending the experimental design to include the interactions between the different pre- and postharvest factors.  

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