An oil-immersed transformer primarily utilizes oil as its insulating medium and relies on oil as a cooling medium (self-cooling, air cooling, water cooling). The primary reasons for placing pebbles in the oil pit of an oil-immersed transformer are for fire prevention and oil drainage.
The area beneath the oil-immersed transformer is commonly referred to as the oil drainage basin or oil drainage, which leads to the emergency oil pit or emergency oil basin. In case of an accident, such as oil spraying or explosion, the transformer oil will flow into the oil drainage pit through the cobblestones and then into the emergency oil basin. At this time, the cobblestones beneath the transformer serve as a barrier, reducing the intensity of the fire and facilitating fire extinguishment. Additionally, the high-temperature transformer oil can be cooled by the cobblestones, which can reduce the intensity of the fire.
Some pools have grilles, while others do not. For those with grilles, the cobblestones are placed on top of the grilles; for those without grilles, the cobblestones are placed in the oil unloading pit. Placing cobblestones facilitates oil unloading, which is one reason. Additionally, insulation, ease of maintenance, and inspection by operating personnel and workers are also reasons.
This prevents the oil from leaking onto the ground and continuing to burn in case of a transformer fire, and also ensures that the oil drainage holes at the bottom of the oil drainage pit are not blocked. The oil flows downwards through the gaps between the cobblestones of the transformer, avoiding oil contamination on the surface. During oil drainage, it also serves to cool the oil temperature, preventing it from burning.
Shenzhen Shentebian Electrical Equipment Co., Ltd. is a high-tech enterprise specializing in the research, development, and manufacturing of power transformers. Its main product lines include oil-immersed transformers, dry-type transformers, and prefabricated substations. As a professional manufacturer certified by the ISO9001 quality management system, the company produces various types of power transformation equipment that comply with IEC international standards. These products are widely used in urban and rural power grid construction, industrial power distribution systems, and new energy power generation fields.
