【Daily Topic】【Electrical Edition 20160726】

The difference between the temperature of a transformer and the temperature of the surrounding air is called the temperature rise of the transformer.

The difference between the temperature of a transformer and the temperature of the surrounding air is called the temperature rise of the transformer.

1. The difference between the temperature of a transformer and the temperature of the surrounding air is called the temperature rise of the transformer.

Regarding the lifespan of transformers, the main cause of insulation aging is temperature. Due to the uneven heat distribution inside the transformer, there are significant temperature differences across its various parts. Therefore, it is necessary to establish limits on the temperature increase in each part of the transformer when it is operating under rated load; these limits represent the allowable temperature rise for the transformer. Typical oil-immersed transformers use Class A insulation, with a maximum allowable temperature of 105°C. The allowable temperature rise for each component is as follows: the allowable temperature rise for the coil is 65°C. Based on Class A insulation at 105°C, when the ambient temperature is 40°C, 105°C – 40°C = 65°C. Since the temperature of the transformer is generally 10°C lower than that of the windings, the allowable temperature rise for the transformer oil is 55°C. To prevent oil aging, the temperature rise of the upper oil surface must not exceed 45°C. In this way, regardless of how the surrounding air conditions change, as long as the temperature rise does not exceed the allowable value, the transformer can operate safely throughout its specified service life.

If the “rated temperature rise” indicated on the transformer’s nameplate refers to the temperature increase that occurs due to heat generation during operation, as compared to the “standard environment”. For oil-immersed transformers, this value is equal to the upper oil temperature of the transformer minus the “standard ambient temperature”” ； For dry-type transformers, this value is equal to the temperature of the transformer windings minus the “standard ambient temperature”. The so-called “standard ambient temperature” is set at 40 degrees Celsius in our country. A standard ambient temperature is specified to provide a unified reference standard for using transformers in different locations and seasons.

The difference between the temperature of a transformer and the temperature of the surrounding air is called the temperature rise of the transformer. To answer this question, it is necessary to mention the allowable temperature rise of transformers, as well as the regulations and criteria behind it Regarding the lifespan of transformers, the main cause of insulation aging is temperature. Due to the uneven heat distribution inside the transformer, there are significant temperature differences across its various parts. Therefore, it is necessary to establish limits on the temperature increase in each part of the transformer when it is operating under rated load; these limits represent the allowable temperature rise for the transformer. Typical oil-immersed transformers use Class A insulation, with a maximum allowable temperature of 105°C. The allowable temperature rise for each component is as follows: the allowable temperature rise for the coil is 65°C. Based on Class A insulation at 105°C, when the ambient temperature is 40°C, 105°C – 40°C = 65°C. Since the temperature of the transformer is generally 10°C lower than that of the windings, the allowable temperature rise for the transformer oil is 55°C. To prevent oil aging, the temperature rise of the upper oil surface must not exceed 45°C. In this way, regardless of how the surrounding air conditions change, as long as the temperature rise does not exceed the allowable value, the transformer can operate safely throughout its specified service life.

It refers to the temperature that is higher than that in a “standard environment” due to heat generation during the operation of the transformer. For oil-immersed transformers, this value is equal to the upper oil temperature of the transformer minus the “standard ambient temperature”” ； For dry-type transformers, this value is equal to the temperature of the transformer windings minus the “standard ambient temperature”.

The difference between the temperature of a transformer and the temperature of the surrounding air is called the temperature rise of the transformer.

The difference between the temperature of a transformer and the temperature of the surrounding air is called the temperature rise of the transformer. Regarding the lifespan of transformers, the main cause of insulation aging is temperature. Due to the uneven heat distribution inside the transformer, there are significant temperature differences across its various parts. Therefore, it is necessary to establish limits on the temperature increase in each part of the transformer when it is operating under rated load; these limits represent the allowable temperature rise for the transformer. Typical oil-immersed transformers use Class A insulation, with a maximum allowable temperature of 105°C. The allowable temperature rise for each component is as follows: the allowable temperature rise for the coil is 65°C. Based on Class A insulation at 105°C, when the ambient temperature is 40°C, 105°C – 40°C = 65°C. Since the temperature of the transformer is generally 10°C lower than that of the windings, the allowable temperature rise for the transformer oil is 55°C. To prevent oil aging, the temperature rise of the upper oil surface must not exceed 45°C. In this way, regardless of how the surrounding air conditions change, as long as the temperature rise does not exceed the allowable value, the transformer can operate safely throughout its specified service life.

The difference between the temperature of a transformer and the temperature of the surrounding air is called the temperature rise of the transformer. Its value is equal to the upper oil temperature of the transformer minus the ambient temperature.