How many degrees Celsius should the temperature of a dry-type transformer not exceed

Temperature regulation for dry-type transformers

What is a regular dry-type transformer

Dry type transformers are typically transformers where the iron core and circuit parts of the transformer are not immersed in insulating oil.

How to control and set the temperature of the temperature controller for dry-type transformers during normal operation:

Temperature control settings for the dry temperature controller: 80 ℃ automatic fan shutdown, 100 ℃ automatic fan on, 130 ℃ high temperature alarm, 150 ℃ ultra-high temperature trip.

Heat resistance level of insulation materials for dry-type transformers

The coil of a dry-type transformer, when using A-grade insulation material, should have a maximum temperature rise of less than 60K when its maximum operating temperature is 105 ℃;

When using E-grade insulation materials, the maximum temperature rise should be less than 75K when the maximum working temperature is 120 ℃;

When using B-grade insulation materials, the maximum temperature rise should be less than 80K when the maximum working temperature is 130 ℃;

When using Class F insulation materials, the maximum temperature rise should be less than 100K when the maximum working temperature is 155 ℃;

When using H-class insulation materials, the maximum temperature rise should be less than 125K when the maximum working temperature is 180 ℃;

When using C-grade insulation materials, the maximum temperature rise should be less than 150K when the maximum working temperature is 220 ℃.

Temperature alarm for dry-type transformers. What to do if the temperature of dry-type transformers is too high

If a high temperature alarm occurs in a dry-type transformer, the first step is to check whether the dry-type transformer is operating under overload. If it operates under overload for a long time, it can cause the transformer temperature to be too high, damage the transformer, and cause ultra-high temperature tripping. It is necessary to report to the transformer manager in a timely manner, apply to cut off the unimportant load, reduce the load of the dry-type transformer to the normal operating load, and record the transformer temperature in a timely manner. When the transformer temperature drops to the operating temperature of the dry-type transformer temperature controller, if the load reduction still cannot reduce the transformer temperature, it is an internal fault of the dry-type transformer. The dry-type transformer should be immediately removed from operation and recorded.

What is the normal temperature for dry-type transformers

The higher the temperature, the greater the resistance of the dry-type transformer winding, and the higher the heat generation, which will decrease efficiency. This is a positive feedback problem. If it is an F-level insulation system, it is more appropriate to control it at 50-60 ℃ for normal operation.

A dry-type transformer that works normally has a temperature of 95 degrees, which is already considered high. We can't increase the load anymore. Low voltage equipment generally requires a temperature rise of no more than 60 degrees (i.e. ambient temperature+60 degrees). Excessive temperature can accelerate insulation aging of equipment and shorten its service life. The limit value of 125K is H-class insulation.

What is the temperature standard for dry-type transformers

GB6450-1986 specifies the temperature rise limit for dry-type transformers.

For the coils of dry-type transformers, when A-grade insulation materials are used, the maximum temperature rise should be less than 60K when the maximum operating temperature is 105 ℃; When using E-grade insulation materials, the maximum temperature rise should be less than 75K when the maximum working temperature is 120 ℃; When using B-grade insulation materials, the maximum temperature rise should be less than 80K when the maximum working temperature is 130 ℃; When using Class F insulation materials, the maximum temperature rise should be less than 100K when the maximum working temperature is 155 ℃; When using H-class insulation materials, the maximum temperature rise should be less than 125K when the maximum working temperature is 180 ℃; When using C-grade insulation materials, the maximum temperature rise should be less than 150K when the maximum working temperature is 220 ℃. Nowadays, most dry-type transformers use H-grade insulation materials, so the temperature of dry-type transformers should generally be below 180 ℃.

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