Oil-immersed transformers are transformers with a body composed of cores and winding and are immersed in tanks full of transformer oils. Transformer oils are used for insulation, with the oil circulation inside the tank transferring heat generated from the winding to a radiator (heat sink) for heat dissipation. Compared to dry transformers, oil transformers offer better overload capacity. As oil ejection or leaks do occasionally occur, oil-immersed transformers are typically used outdoors, and feature relatively lower prices.