Oil-immersed power transformers are the most widely adopted type, serving high-voltage, large-capacity power transmission and distribution systems. Their applications span generating plant step-up, grid transmission, substation step-down, and industrial factory distribution. Driven by the rollout of renewable energy projects (wind and solar), Ultra-High Voltage (UHV) initiatives, smart grid development, and urban-rural grid upgrades, demand for these transformers continues to expand. Concurrently, evolving energy efficiency standards and stringent environmental regulations are accelerating the transition from conventional units to low-loss, eco-friendly models, thereby stimulating market demand for energy-efficient and environmentally sustainable oil-immersed transformers.