Electrical transformers are marvels of engineering. They allow industries and electrical grids of all kinds to transform power for various applications. These marvels of engineering have a complex design, much like the human body. While every part is interconnected and plays a unique role in ensuring efficient voltage transformation, we will explore eleven critical components of these transformers and detail their function and significance in systems.
1- Core
The core is the most important part of a transformer. It provides a low reluctance magnetic path that channels the flux between the primary and secondary windings, ensuring minimal energy loss. The core is usually constructed from laminated silicon steel sheets to reduce eddy currents and hysteresis losses. There are two different designs: one in which the windings surround the core limbs and one in which the core surrounds the windings.
2- Windings
Windings, also known as primary and secondary coils, are the most important component in every transformer design. They conduct current and create electromagnetic induction, which ensures safe and efficient operation. The primary winding receives the input voltage, and the secondary winding delivers the transformer output. Depending on the type of transformer, the windings can be made of copper or aluminum. Helical windings are typically used for high-current applications, and disc windings are used for high-voltage transformers.
3- Insulation Systems
Insulation systems are designed to electrically isolate conductive parts, such as windings and cores, in order to prevent arcing and short circuits. Depending on the type of transformer, the insulation can be solid or liquid. Solid insulation is produced from materials such as pressboard, Nomex, or epoxy resin. Liquid insulation usually uses a special kind of mineral oil or silicone fluid.
4- Tank / Enclosure
The tank contains the core, windings, and insulating system. It is designed to protect the internal components from environmental damage. For durability, it is typically made of steel, aluminum, or stainless steel. Oil transformer tanks usually include additional parts, such as radiators and bushings, while dry-type transformers use ventilated enclosures for efficient air cooling.
5- Bushing
A bushing is an insulated connector that links internal windings to external power lines with minimal power loss and high efficiency. Bushings are usually made of porcelain, polymer, or composite for applications requiring high dielectric strength. Condenser bushings are typically used in high-voltage applications with capacitive grading, while simpler, solid bushings are used in lower-voltage applications.
6- Tap Changer
Tap changers are crucial for every transformer because they adjust the turn’s ratio to regulate the output voltage under varying load conditions. There are two types of tap changers: on-load and off-circuit, depending on the transformer type and application needs.
7- Cooling System
The cooling system is one of the most important components of a transformer system, ensuring high efficiency and equipment safety. Depending on the type of transformer, cooling can be liquid or air. Cooling systems typically contain essential components, such as radiators and cooling fans, to ensure optimal performance.
8- Conservator Tank
The conservator tank compensates for oil expansion or contraction caused by temperature changes. It is primarily used in oil- or liquid-immersed transformers. There are two different designs of conservator tanks. One design is a sealed auxiliary tank mounted above the main tank, and the other is connected via a pipe with a bladder or diaphragm that separates the oil from the air.
9- Breather
A breather is an essential component of almost every transformer that prevents moisture from entering the conservator by filtering the incoming air. It usually has an oil seal to trap dust and humidity, as well as silica gel crystals to absorb moisture. Since moisture and humidity are major hazards for transformers, breathers can be considered crucial for every application.
10- Buchholz Relay
Buchholz relays function as detectors for internal faults, such as arcs, gas bubbles, and other malfunctions, especially in oil-filled transformers. The device can be installed between the conservator and the main tank. When gas accumulates, it tilts a float inside the transformer, triggering an alarm. Additionally, several faults, such as arcs, cause the circuit breaker to trip and prevent damage.
11- Pressure Relief Device
The function of a pressure relief device is to vent excess pressure caused by internal arcs or explosions in order to prevent tank rupture. This durable transformer component is designed as a spring-loaded diaphragm or rupture disc. The device reseals automatically after releasing pressure.
Understanding the 11 key parts of an electrical transformer can answer many questions, but these marvels of engineering have various other parts and components to ensure efficiency and safety.