What Is an Oil Filled Transformer?
An oil-filled transformer’s magnetic circuit and windings are immersed in oil. The oil typoe transformers are used in power distribution or electrical substations. Mineral oil is mainly used for oil. A transformer is a device that uses two coils to convert voltage. The coils are called the primary and secondary windings, respectively, and the winding ratio determines the ratio of primary to secondary voltage.
Oil-type transformers can be ground-, pad- or pole-mounted for use outdoors. They deliver efficient performance in diverse applications including transmission and distribution networks, renewable energy generation, and small industries.
Applications of Oil Filled Transformers
Oil-Filled Transformers are used in a variety of applications and fields. The most common application is power transmission and distribution. Electricity produced in power plants is generally of high voltage.
This power is supported by towers and other structures while being sent out to the transmission lines. By using Oil-Filled Transformers, this high-voltage power can be converted and supplied to low-voltage distribution lines.
The low-voltage power is then transmitted to demand locations such as homes, factories, and commercial facilities. Oil-Filled Transformers are also used at these demand points to convert the voltage to a level suitable for the demand. General households use voltages such as 100 VAC or 200 VAC, while factories and commercial facilities may use 200 VAC or 400 VAC.
Principle of Oil Filled Transformer
An Oil-Filled Transformer consists of an iron core, coils, oil tank, and insulating oil.
1. Iron Core
The iron core is located at the center of the transformer. The iron core is made by laminating silicon steel plates and other materials to form a magnetic circuit. The multilayer structure minimizes magnetic losses and enables efficient power conversion.
2. Coil
Around the iron core are windings for the high-voltage and low-voltage sides, respectively. They are made of copper or aluminum wire and generate a magnetic field when current flows through them. In a typical step-down transformer, the high-voltage side has fewer windings and the low-voltage side has more windings.
3. Oil Tank
These components are housed in a steel tank. The tank is filled with insulating oil, which protects the transformer structure while insulating the interior. The tanks are often fitted with fins to help circulate the cooling oil and dissipate heat.
4. Insulating Oil
Mineral oil is widely used as insulating oil. In recent years, transformers using sunflower oil or rapeseed oil have been marketed in consideration of the environment. While expensive, they can prevent environmental pollution due to leakage accidents.
In addition, the deterioration status of transformers can be monitored by analyzing the concentration of organic gases inside the insulating oil. When a transformer overheats, ethylene and ethane are generated, and acetylene and hydrogen are produced by partial discharge. Acetylene is an organic gas that must not be detected even in trace amounts because it is a gas caused by internal transformer abnormalities.