Against the background of the accelerated construction of a new power system and the rapid development of new energy industry, the oil-immersed transformer, as a key power conversion equipment, has become an indispensable core component in the power grid. With its mature technology, stable performance and large capacity adaptation, it is widely used in various high-voltage power transmission and distribution scenarios. This article comprehensively elaborates on its definition, working principle, structural composition, application scenarios, selection and maintenance, as well as industry development trends, providing a comprehensive reference for industry practitioners and relevant users.

1. Overview & Working Principle

The prefabricated substation, as an integrated power distribution solution, has the core feature of factory pre-installation and on-site rapid commissioning. Among them, the oil-immersed transformer, as the core component of voltage conversion, is mainly used in outdoor large-load scenarios, with the advantages of high efficiency, stable operation and strong adaptability. The entire power transmission and distribution process is efficient and safe, which is an important link connecting the power grid and terminal power consumption.

Working Process of Power Distribution System: High-voltage power is input into the high-voltage chamber, processed by the protection system, converted by the oil-immersed transformer, and then distributed to each terminal load through the low-voltage distribution system, forming a complete power supply chain from high-voltage input to terminal power consumption.

2. Core Structure & Components

2.1 Box Body (Outer Protection)

Made of high-quality galvanized steel plate and composite material, it has excellent corrosion resistance and weather resistance, reaching IP43 protection level. It is suitable for outdoor long-term operation, effectively isolating the external harsh environment and ensuring the stable operation of internal components.

2.2 Core Electrical Components

• Oil-Immersed Transformer: The core voltage conversion component, suitable for outdoor large-load scenarios, with stable performance and long service life.

• High-Voltage Switchgear: Including load switch and isolating switch, used for high-voltage circuit control and protection, ensuring safe operation of the power grid.

• Low-Voltage Distribution Cabinet: Equipped with reactive power compensation device and electric energy metering module, realizing power distribution and quality monitoring.

2.3 Auxiliary System

Heat dissipation system: Natural cooling and forced air cooling are adopted to adapt to different load and environmental requirements; Monitoring system: Real-time monitoring of equipment operation status, realizing remote early warning and fault handling; Other accessories: Grounding device, maintenance lighting and hoisting components, ensuring convenient operation and stable operation.

3. Classification & Application Scenarios

3.1 Classification by Structure

European-style integrated structure (stable performance, easy maintenance) and compact integrated structure (small size, low cost), suitable for different load and space requirements.

3.2 Voltage Level Classification

Medium-voltage type (10kV/35kV): Mainstream type, widely used in various industrial and civil scenarios; Low-voltage type: For terminal short-distance power distribution; High-voltage type: For large-scale power hub projects.

3.3 Main Application Scenarios

Urban power grid renovation, residential communities, industrial parks, new energy power stations (wind power, photovoltaic), temporary power supply for construction sites, high-speed rail supporting facilities, etc. It is an important supporting equipment for new energy grid connection and urban power supply.