A high-voltage test transformer is a static electrical device used to convert an alternating voltage (current) of one value into another voltage (current) of the same frequency but different values. It is the main equipment for transmitting and distributing electrical power in power systems. Power transformers primarily step down high-voltage electricity from the grid to usable voltages of 6000 volts (V) or 380 volts (V) to supply power to electrical equipment.

If overload or short circuit occurs inside the transformer, the insulating material or insulating oil may decompose, expand, and even vaporize due to high temperature or electric sparks, causing a sharp increase in internal pressure. This may lead to an explosion of the transformer casing, with a large amount of insulating oil spraying out and burning, and the oil flow can further spread the fire hazard.

　　High-voltage test transformers should pay attention to the following during operation:

　　(1) Avoid overload operation: Prolonged overload operation can cause the coils to heat up, gradually aging the insulation and leading to short circuits.

　　(2) Regularly inspect the quality of insulating oil: The oil quality should be tested periodically, and unqualified oil should be replaced promptly or other measures should be taken.

　　(3) Prevent aging and damage of the transformer core insulation: Prolonged heating of the core can cause insulation aging.

　　(4) Prevent damage to insulation due to careless maintenance: If abrasion or damage is found, handle it promptly.

　　(5) Ensure good contact of conductors: Poor contact can cause local overheating.

　　(6) Prevent lightning strikes: Transformers can be burned out due to insulation breakdown caused by lightning.

　　(7) Short-circuit protection: If a short circuit occurs in the transformer coils or load, and the protection system fails or the protection setting is too high, the transformer may be burned out. Therefore, reliable short-circuit protection should be installed.

　　(8) Maintain good grounding.

　　(9) Ventilation and cooling: If the transformer coil conductors use Class A insulation, the insulation is mainly made of paper and cotton yarn. For every 8°C increase in temperature, the insulation life is reduced by about half. When the transformer operates normally below 90°C, its lifespan is about 20 years; if the temperature rises to 105°C, the lifespan is 7 years. During operation, the transformer should maintain good ventilation and cooling.