Temperature regulations for dry-type transformers, operating environment temperature regulations, and starting temperature regulations for winding fans

Temperature regulation for operating environment of dry-type transformers

Why use a dry-type temperature controller, mainly because dry-type transformers need to control temperature, so what is the normal upper limit of dry-type transformer temperature? FJINNO Technology tells you:

A normal working dry-type transformer (Class A) with a temperature of 95 ℃ is already considered high. This transformer has always been loaded at around 60%, with a temperature of around 75 ℃. The main issue is that the cooling fan is broken and cannot be forced to dissipate heat. Otherwise, 100% of the load would be fine.

Low voltage equipment generally requires a temperature rise not exceeding 60 ℃ (i.e. ambient temperature+60 ℃). Excessive temperature can accelerate insulation aging of equipment and shorten its service life. The limit value of 125K is H-class insulation

The national standard 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 ℃.

Most dry-type transformers now use H-grade insulation materials, so it is generally said that the temperature of dry-type transformers should be below 180 ℃ (on-site transformers are F-grade), and the theoretical maximum temperature can reach 155 ℃.

Temperature regulation for winding of dry-type transformers

The temperature rise limit of dry-type transformer winding should not exceed 155 ℃, and the maximum allowable temperature of dry-type transformer winding should not exceed 155 ℃

Specification for starting temperature of dry-type transformer fan

When the temperature of the dry-type transformer reaches what level during operation, the fan starts to start,

The normal temperature for SCB10's dry transformer is around 60-70 degrees Celsius, and if it is set, we usually set the fan to stop when it starts at 100 degrees Celsius and returns to 80 degrees Celsius, with an alarm at 130 degrees Celsius and a trip at 150 degrees Celsius. So the tripping port of the controller must be connected to the microcomputer protector of the high-voltage output cabinet of this transformer or the tripping circuit, otherwise it will not play a protective role.

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