How to choose Transformer oil?

Transformer oil is a kind of pure, stable, low viscosity, good insulation and cooling light yellow transparent liquid obtained from natural oil through distillation and refining. It is a mixture of natural hydrocarbons. Transformer oil plays the role of strengthening insulation, heat dissipation, anti-corrosion and arc extinguishing in transformer. Due to the high quality requirements of transformer oil, it is difficult to explain whether the transformer oil is qualified without oil test. According to the 30 years of transformer manufacturing experience of hengfengyou electric, the following methods can be used to simply judge whether the transformer oil is qualified or not.

1、 By smelling transformer oilQualified transformer oil should have no smell or a little kerosene smell. If there is other smell, it means that the oil quality has deteriorated. To identify the odor, the oil sample should be stirred and slightly heated. A few drops of oil can be dropped onto the clean hand and rubbed to identify the odor. For example, if the oil has a burnt smell, it means that the oil is not dry; if the transformer oil has an acetylene smell, an arc will be generated in the oil; if the transformer oil has a sour smell, it means that the oil has seriously aged.

2、 By observing the characteristics of transformer oilA. Clarity of oilThe clearer the oil, the better. There should be no sediment or floating objects. The new transformer oil is generally light yellow. After a period of operation, its color will change to dark yellow and light red. Dark color of new transformer oil is not allowed. If the color of the new transformer oil turns dark rapidly during operation, it means that the oil quality is deteriorated.B. Transparency of oilPlace the transformer oil of the test tube in an environment of minus 5 degrees. If the oil is no longer transparent, it means that there are free carbon and mechanical impurities in the transformer oil, and the product is unqualified.C. Fluorescence reaction of oilThe new oil installed in the new pipe will have green or blue purple fluorescence. If the fluorescence is lost, the transformer oil is not new.

3、 Through professional oil experiment.Through professional oiling experiments (withstand voltage test, dielectric loss test and simplified test), we can analyze the moisture content of the oil, whether the gas content exceeds the standard, whether there is free carbon, withstand voltage index, etc. the test results are compared with the national electric power standard, and the values within its range can show that the transformer oil is qualified. Hengfengyou electric adopts Kunlun lubricating oil 25# and 45# transformer oil of PetroChina, and implements China’s national standard GB / T 7595-2017. All the oil chemical test indexes meet the national standard, ensuring the long-term safe and stable operation of the transformer, and meeting the oil chemical test requirements. For more information, please visit the official website of hengfengyou electric https://www.hengfengyou.com .

4、 Insulation oil test items and standards of China National Transformer Oil Standard (GB 50150-2006)1. The appearance is transparent without impurities or suspended solids;2. Water soluble acid (pH value) > 5.4;3. Acid value mgKOH / G: ≤ 0.03;4. Flash point (℃): not lower than db-10:140 / db-25:140 / db-45:135;5. Moisture content (mg / L): 500kV: ≤ 10; 220-330kv: ≤ 15; voltage class of 110kV and below: ≤ 206. External tension (25 ℃): (Mn / M) ≤ 357. Dielectric loss factor TANF (%): at 90 ℃, it is ≤ 0.5 before injecting into electrical equipment and ≤ 0.7 after injecting into electrical equipment8. Breakdown voltage: 500kV: ≥ 60kV; 330kV ≥ 50kV; 60-220kv ≥ 40kV; 35kV and below voltage level ≥ 35kVSupplementary note: if it is preventive test, the requirements are different. Please refer to DL / T596-1996 code for preventive test of electrical equipment for details.

Published by hengfengyou

Qingdao Hengfengyou Electrical Engineering Co., LTD., subordinate to Hengfengshuai Group, is an export-oriented enterprise with transmission and distribution industry as its main business, integrating product research and development, manufacturing and trade. Its main products include power transformers, medium and low voltage switch cabinets, circuit breakers and other power distribution equipment and power engineering services.

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