The transformer in operation must pay attention to the following points:
1. Prevent transformer overload operation. If overloaded for a long time, it will cause the coil to heat up, gradually aging the insulation, causing inter box short circuit, phase short circuit or ground short circuit, and oil decomposition.
2. Ensure the quality of insulation oil. During storage, transportation, or operation and maintenance of transformer insulation oil, if the oil quality is poor or there are too many impurities or moisture, it will reduce the insulation strength. When the insulation strength decreases to a certain value, the transformer will short-circuit and cause electric sparks, arcs, or dangerous temperatures. Therefore, during operation, the transformer should undergo regular oil quality testing, and unqualified oil should be replaced in a timely manner. Add Security Engineer Site to Favorites
3. Prevent aging and damage to the insulation of the transformer core. Aging of the insulation of the iron core or damage to the clamping bolt sleeve can cause significant eddy currents in the iron core, leading to long-term heating of the iron core and insulation aging.
4. Prevent insulation damage due to careless maintenance. When repairing the hanging core of a transformer, attention should be paid to protecting the coil or insulation sleeve. If any scratches or damages are found, they should be dealt with in a timely manner.
5. Ensure good wire contact. Poor contact between the internal connectors of the coil, as well as the connection points between the coils, the contacts leading to the high and low voltage side bushings, and the various support points on the tap changer, can cause local overheating, damage insulation, and lead to short circuits or open circuits. The high-temperature arc generated at this time will cause the insulation oil to decompose, producing a large amount of gas and increasing the pressure inside the transformer. When the pressure exceeds the protection setting of the gas circuit breaker without tripping, an explosion will occur.
6. Prevent electric shock. The power supply of power transformers is generally supplied through overhead lines, which are prone to lightning strikes and can cause the transformer to burn down due to insulation breakdown.
7. Short circuit protection should be reliable. If a short circuit occurs in the transformer coil or load, the transformer will withstand a considerable short-circuit current. If the protection system fails or the protection setting is too large, it may burn the transformer. For this reason, reliable short-circuit protection devices must be installed.
8. Maintain good grounding. For low-voltage systems that use protective grounding, the neutral point on the low-voltage side of the transformer should be directly grounded. When the three-phase load is unbalanced, current will appear on the neutral line. When the current is too high and the contact resistance is high, a high temperature will occur at the grounding point, igniting the surrounding combustible materials.
9. Prevent overheating. Temperature changes should be monitored during transformer operation. If the transformer coil wire is A-grade insulation, the insulation is mainly made of paper and cotton yarn, and the temperature has a significant impact on the insulation and service life. For every 8 ℃ increase in temperature, the insulation life will be reduced by about 50%. The transformer operates at normal temperature (90 ℃) and has a lifespan of approximately 20 years; If the temperature rises to 105 ℃, the lifespan is 7 years. If the temperature rises to 120 ℃, the lifespan is only two years. So when the transformer is running, it is necessary to maintain good ventilation and cooling. If necessary, forced ventilation can be adopted to reduce the temperature rise of the transformer