Dry-type transformers have strong compressive capacity. Epoxy resin can be degassed, dehumidified, and cast as a whole without adding fillers for vacuum drying. These dry type transformer types have high mechanical strength, prevents short-circuits, and has a certain impact resistance.
The head and end of the high-voltage winding and the middle tap are embedded with copper inserts, which have good rigidity, are easy to adjust, and are beautiful and neat. In order to meet the above requirements, all aspects of dry-type transformer manufacturing need to be carefully handled.
The iron core is made of new cold-rolled silicon steel sheets, with a 45-degree full oblique multi-step joint. The surface is covered with resin insulating coating, which is resistant to moisture, rust and noise. The iron core, the clamp and the coil are clamped by elastic parts, so that the coil is in a stable pressing state to reduce noise.
A thermostat is required. A platinum resistor (PtlOO) is placed in the pre-buried hole on the top of the low-voltage coil. To monitor the temperature rise of the dry-type transformer winding, automatically stop the cooling fan, and have the functions of fault warning sound, over-temperature warning sound and over-temperature tripping, china transformer manufacturer provides a reliable overload protection device for the dry-type transformer, thereby improving the smoothness of the dry-type transformer operation.
When the natural air is cold to (AN), under normal use conditions, the transformer can continuously output the rated capacity. When the forced air is cooled to (AF), the transformer can continuously output 150% of the rated capacity (2h) without affecting the service life of the transformer.
Dry-type transformers need to be equipped with a temperature and humidity system. The temperature and humidity system will measure the temperature signal through the Pt100 thermistor embedded in the low-voltage winding, visually display the temperature of each phase winding, and should have an over-temperature alarm signal. The thermostat can control the operation of the air cooler according to the winding temperature. The thermostat is arranged on the transformer box.
In the case of transformers of the same industrial design and of the same numerical rating, the electrical performance will then be exactly the same. In the same case, they are interchangeable and can run side by side.
The structure of the transformer should be conducive to smooth transportation to the destination, and the dry-type transformer should be able to enter a continuous working state immediately after the accessories installed on site are installed.
The transformer and its accessories shall be designed, manufactured and assembled so that the vibration is small and can withstand the action of three-phase short-circuit electric power. All leads from bushing terminals and adapter taps shall be connected to a terminal strip of solidly supported insulating material.
The dry-type transformer follows the self-cooling design. The high or low-voltage coil cylinder wall of the dry-type transformer as a whole will be equipped with longitudinal ventilation channels in advance, and a forced air cooling device (cooling fan) can be configured accordingly. After that, a certain output capacity can be increased.
We have occasionally encountered such a situation: when the dry-type transformer is working, the temperature will suddenly rise sharply, what is the reason? Is there any harm?
When the dry-type transformer is working, the temperature also continues to rise, but this is a continuous and slow process. For dry-type power transformers, the temperature rise is achieved by external work.
However, sometimes dry-type transformers experience a process of sharp rise in temperature, which makes the performance of dry-type transformers continue to be disordered and faults continue to increase.
When such a fault occurs in a dry-type transformer such as the amorphous alloy dry type transformer, we cannot be sloppy, because this situation has the impact of explosion and fire. So in this case, how do we judge the cause of the dry-type transformer and the corresponding solution?
1. Short circuit between iron core silicon steel sheets
Due to external force damage or insulation aging, the insulation between the silicon steel sheets is damaged, and the eddy current becomes larger, resulting in local overheating.
2. The tap switch is in poor contact
Due to insufficient pressure at the contact point of the dry-type power transformer tap-changer or contamination at the contact point, the contact resistance becomes larger and the contact is heated, especially after the tap is switched or the transformer is overloaded, it is more likely to cause the tap-changer to have poor contact and heat.
3. Short circuit between turns of coil
The inter-turn short circuit reduces the number of coil turns and closes the resulting short circuit circulation, resulting in a high temperature at the short circuit. Serious inter-turn short circuit causes the oil temperature to rise, and the oil at the short-circuit point of the dry-type transformer makes a "gurgling" sound.
