What Is a Main Transformer Its Working Principle Components and Applications?

Main Transformer

The main transformer is primarily responsible for converting the high-voltage electrical energy generated at power plants into lower-voltage electrical energy suitable for transmission, distribution, and end-use. This process involves stepping down voltage from high to low levels.

Working Principle

The main transformer operates based on the principles of electromagnetic induction and voltage transformation. When an alternating current (AC) is applied to the high-voltage winding, it generates an alternating magnetic flux in the core. This varying magnetic field is transferred through the core to the low-voltage winding. According to Faraday's law of electromagnetic induction, the changing magnetic flux induces an electromotive force (EMF) in the low-voltage winding, thereby achieving the conversion of electrical energy from high voltage to low voltage.

Components

The main transformer consists of several key components: the core, oil tank and cover, protective devices, cooling system, and bushings. The core assembly, which performs the electromagnetic energy conversion, includes the iron core, windings, leads, and insulation. The oil tank and cover comprise the tank body, top cover, base, and associated accessories such as oil sampling valves, drain plugs, and grounding bolts. Protective devices include the conservator, oil level gauge, oil purifier, flow relay, desiccant breather, and signal thermometer.

Applications

Main transformers are widely used across the three major stages of the power system: transmission, distribution, and utilization. They also find extensive applications in industrial facilities, construction sites, and residential areas, including use in power machinery, welding equipment, arc furnaces, power supply and distribution systems, and indoor lighting systems.