56 Power & Mains Transformers 3

Power and mains transformers are types of electrical transformers used in power transmission and distribution systems to convert high voltage and low current to low voltage and high current or vice versa. They are essential components in the electricity grid, and are used to step up or step down voltage levels for efficient transmission and distribution of electrical energy.

Power transformers are used in high voltage transmission systems, typically at voltages of 110 kV and above, to step up or step down the voltage levels. They have a high power rating, typically ranging from several hundred kVA to several thousand MVA, and are designed to handle high currents and voltages without overheating or breaking down. Power transformers are typically oil-immersed, and use a magnetic core made of laminated steel to reduce losses and improve efficiency.

Mains transformers, also known as distribution transformers, are used in low voltage distribution systems, typically at voltages of 11 kV or below, to step down the voltage levels for use by consumers. They have a lower power rating than power transformers, typically ranging from several kVA to several hundred kVA, and are designed to operate at lower voltages and currents. Mains transformers are typically dry-type, and use a magnetic core made of laminated steel or ferrite to reduce losses and improve efficiency.

Both power and mains transformers require proper design, selection, and maintenance to ensure reliable and efficient operation. They are subject to various standards and regulations, such as IEC (International Electrotechnical Commission) and IEEE (Institute of Electrical and Electronics Engineers), to ensure their safety and performance. Proper installation and maintenance of transformers, such as regular inspection, testing, and oil analysis, are also critical to ensure their longevity and performance.