Maintenance Matters Needing Attention in Transformer Operation

The transformer is a device that changes the AC voltage. The main components are the primary coil, the secondary coil and the iron core (magnetic core). In electrical equipment and wireless circuits, transformers are often used for raising and lowering voltage, matching impedance, and safe isolation. However, transformers are also electrical equipment. After working for a period of time, the transformers also need to be maintained. However, when the electrical transformers are generally in a 24-hour working state, the maintenance items to be paid attention to during the operation of the transformer are particularly important.

1. Prevent overload operation of the transformer. Long-term overload operation will cause the coil to heat up and gradually deteriorate the insulation, causing short circuits between boxes, short circuits between phases, or short circuits to ground, and oil decomposition.

2. Ensure that the wires are in good contact. Poor contact of the internal joints of the coils, poor contact between the connection points between the coils, the contacts leading to the high and low voltage side bushings, and the fulcrums on the tap changer, will cause local overheating, damage the insulation, and cause a short circuit or open circuit. The high-temperature arc generated at this time will decompose the insulating oil, produce a large amount of gas, and increase the pressure in the transformer. When the pressure exceeds the protection value of the gas circuit breaker without tripping, an explosion will occur.

3. Maintain a good grounding. For the low-voltage system using protective zero connection, the neutral point of the low-voltage side of the transformer should be directly grounded. When the three-phase load is unbalanced, current will appear on the zero line. When this current is too large and the contact resistance is large, high temperature will appear at the grounding point, igniting the surrounding combustible materials. 

4. to ensure the quality of insulating oil. In the storage, transportation, or operation and maintenance of transformer insulating oil, if the oil is of poor quality or excessive impurities or moisture, the insulation strength will be reduced. When the insulation strength is reduced to a certain value, the transformer will be short-circuited and cause electric sparks, arcs or dangerous temperatures. Therefore, the oil quality of the transformer should be tested regularly during operation, and the unqualified oil should be replaced in time. Add the safety engineer site to your favorites.

5. Prevent electric shock. The power supply of a power transformer generally comes from an overhead line, and the overhead line is prone to lightning strikes, and the transformer will burn out due to insulation breakdown.

6. short-circuit protection must be reliable. If the transformer coil or load is short-circuited, the transformer will withstand a considerable short-circuit current. If the protection system fails or the protection setting is too large, the transformer may be burned. For this reason, a reliable short-circuit protection device must be installed.

7. Prevent aging and damage of transformer core insulation. The iron core insulation is aging or the clamping bolt sleeve is damaged, which will cause the iron core to produce a large eddy current, which will cause the iron core to heat up for a long time and cause the insulation to age.

8. Prevent inadvertent damage to the insulation during maintenance. When overhauling the hanging core of the transformer, pay attention to protecting the coil or insulating sleeve. If scratch damage is found, it should be dealt with in time.

9. Prevent over-temperature. The temperature change should be monitored while the transformer is running. If the transformer coil wire is A-class insulation, the insulator is mainly paper and cotton yarn. The temperature has a great influence on the insulation and service life. When the temperature rises by 8 ℃, the insulation life will be reduced by about 50%. The transformer runs at normal temperature (90 ℃), (examination-large) life is about 20 years; if the temperature rises to 105 ℃, the life is 7 years 5 temperature rises to 120 ℃, the life is only two years. Therefore, when the transformer is in operation, good ventilation and cooling must be maintained, and forced ventilation can be adopted when necessary to achieve the purpose of reducing the temperature rise of the transformer.