Eleven transformers are the most basic knowledge that electricians should understand!

Transformers are an important electrical equipment in the process of power transmission, transformation, and distribution in the power system. Whether it's industrial enterprises, shopping malls, office buildings, or residential areas, transformers can be seen everywhere. The role of transformers in the power industry is extremely important. As a power practitioner, you must understand the knowledge of transformers. Below are 11 common knowledge about transformers that I have summarized for you. After reading, you will have a new understanding of transformers.

1. The principle of transformers

A transformer is a device that uses the principle of electromagnetic induction to change the AC voltage and current. Its main components are the primary coil, secondary coil, and iron core (magnetic core). The following diagram shows several transformers with different shapes.

2. The function of transformers

Variable voltage: Increasing or decreasing the voltage, converting the voltage detected by the generator into a voltage level for residential or industrial use through the process of boosting, transmitting, and reducing voltage.

Variable current: Changing the voltage while changing the magnitude of the current

Isolation: Isolating the user system from the power supply system to narrow down the scope of accidents.

3. What types of transformers are there

A. Oil immersed transformer: a transformer that uses transformer oil as the insulation and cooling medium, with the iron core and coils completely immersed in the insulating oil.

B. Dry type transformer: The iron core and coil are cast with epoxy resin material to provide insulation.

C. Amorphous alloy transformer: A new type of transformer developed in recent years, which uses amorphous alloy materials as magnetic circuit materials and has good temperature resistance.

4. What are the components of a transformer

A. Body: including iron core, winding, insulation support

B. Voltage regulation device: namely tap changer, (on load voltage regulation device and off excitation voltage regulation)

C. Fuel tank and fin shaped radiator (wings), sleeve

D. Safety devices: moisture absorbers, gas relays, oil filters, and temperature measuring instruments.

5. What is the use of transformer oil

(1) Insulation effect: The specific strong insulation performance of transformer oil generates sufficient insulation strength between the winding and the shell. Common types include DB25 and DB45.

(2) Heat dissipation effect: Transformer oil naturally circulates between the body and the sheet shaped radiator based on the principle of heating rise, dissipating heat through the radiator to maintain the temperature of the coil not too high.

(3) Arc suppression function: When operating the on load voltage regulation device, an arc light is generated when the tap changer is opened, and the transformer oil can extinguish the arc light, providing protection.

6. The function of oil storage tank (conservator)

The oil conservator (oil storage tank) is installed diagonally above the oil tank, and there is an oil pipe connected to the oil tank. When the volume of transformer oil expands and shrinks with changes in oil temperature, the oil conservator plays a role in storing and replenishing oil. Prevent oxidation and moisture from oil and air contact. The oil conservator is equipped with an oil gauge tube, and some are also equipped with a liquid level indicator to observe changes in the oil level.

7. What is on load voltage regulation?

On load voltage regulation is a voltage regulation method in which a transformer can change its voltage by switching the tap position during load operation.

8. What are the losses of transformers during operation

Transformer losses include: no-load loss (iron loss): losses caused by eddy currents in the iron core, load loss (copper loss): losses caused by heating of the winding resistance.

9. Representation method of transformer model

Basic model: S

Design number or performance level code: 11

Rated capacity: 500KVA

High voltage side voltage: 10KV

10. What are the main technical data on the nameplate

Transformer primary and secondary rated voltage, rated capacity, wiring group, primary and secondary rated current, variable impedance voltage, tap changer adjusted voltage range, operating environment conditions, transformer oil type and weight, etc.

11.What is the function of a moisture absorber (respirator)?

A. Due to the constant temperature changes during operation of the transformer, the oil level inside the transformer may increase or decrease, and the gas must be discharged, otherwise the pressure will increase; It can be understood as the process of breathing, which plays a role in preventing direct contact between oil and air from deteriorating.

B. Install a silicone tank on the exhalation channel of the oil, and the transformer breathes through the silicone. The discharged water is absorbed, and when the water reaches a certain level, the color of the silicone will change from blue to red. At this time, the silicone needs to be replaced. As shown in the figure.

12. What is a gas relay? What is the function?

Gas relay (also known as gas relay) is a protective device used in transformers, installed between the pipeline between the oil storage tank and the oil tank of the transformer. When an internal fault in the transformer causes oil to decompose and produce gas or oil flow surge, the contact of the gas relay is activated, and the internal electrical normal contact sends a "heavy gas" trip signal and a "light gas" alarm signal to the on duty personnel, Reminder that the transformer is abnormal or faulty.