The safety operation and service life of dry-type transformer types depend on the safety and reliability of the coil insulation. The main reason for the insulation damage caused by temperature is that the coil temperature exceeds the insulation strength, which makes the dry-type transformer unable to operate normally. Therefore, temperature monitoring and alarm control of dry-type transformer types are very important.
Because the construction of dry-type transformer types is internal and external, it is composed of iron core, low-voltage coil, and high-voltage coil. The heat source is the iron core and low-voltage coil, and the high-voltage coil on the external surface has less current, so less heat is generated. Therefore, the cooling effect of dry-type transformer types and air conditioning is not good when using ordinary axial flow fans.
Special cooling pipelines are left in the manufacturing of dry type transformer types. Only with a special temperature control device can the expected effect be achieved.
To meet the requirements of unmanned substations, it is recommended to set up a wind-cooled temperature control system on the existing transformer at the substation and carry out ventilation transformation on the switchgear. If the temperature is too high, the ventilation cooling device can be automatically started.
The temperature signal is measured by the PT 100 thermistor buried in the heat portion of the low-voltage coil. When the load of the dry-type transformer increases and the operating temperature rises, the coil temperature reaches a certain value (this value can be adjusted).
The F-class dry-type insulation transformer is generally set to 110℃, and the system automatically starts the fan for cooling. When the coil temperature drops to a certain value (this value can also be adjusted, the F-class dry-type insulation transformer is generally set to 90℃), the system automatically stops the fan.
The dry-type transformer is an important power equipment and instrument, but because the various parts in the dry-type transformer are relatively large, there are multiple production processes and production processes for the manufacture of dry-type transformer types.
Ordinary dry-type transformer types are prepared through many steps and installation methods, and the specific production steps are as follows:
Winding (according to process parameters, set the number of coils and the thickness of copper wire, wind on the framework, and use wires to separate the primary and secondary poles)
Insertion (close the wound coil with an E-shaped or diagonal F-shaped silicon steel plate)
Dip coating (immerse in thick insulation paint)
Drying (bake to absolute dryness)
Basically, dry-type transformer types are made in this way. Dry-type transformer factories also have winding, insertion, paint spraying (including the oven machine). These are naked dry-type transformer types.
Some chinese transformer manufacturers also have assembly workshops, which assemble dry-type transformer types and rectifier circuit boards together to form various power adapters for other electronics factories to use.