Which of the following oil is by far the most common and the cheapest liquid used as an insulating fluid in a transformer?
Right Answer is:
Paterloelum Based Mineral Oil
SOLUTION
Types of Transformer oil
The insulating liquids that can be used for transformers are
- Mineral petroleum-based oils
- Askarels
- Vegetable oils
- Organic esters
- Polyhydrocarbon liquids
- Fluorinated liquids
- Silicone liquids.
Petroleum-based mineral oil is by far the most common and the cheapest liquid used as an insulating fluid, and the use of other insulating oil can be several times costlier and can only be justified economically in circumstances where technical advantages are to be gained.
Mineral Insulating Oils
Until now, mineral oil has been the most widely used fluid in electrical equipment that serves the dual purpose of electrical insulation and heat dissipation. There are some synthetic liquids available as alternatives, but the enhanced cost of such liquids masks their performance in widespread uses. As a consequence, mineral oil still serves as the most popular liquid insulation for electrical equipment.
Composition of Mineral Oil
Mineral oils to be used for electrical apparatus are basically derived from crude petroleum through a distillation and refining process. The composition of such crude petroleum can vary depending on its geographical source. Basically, all mineral oils are mixtures of various hydrocarbon compounds with different chemical structures. Some crude oils can have, in addition to hydrocarbons of different molecular structures, some paraffinic as well as naphthenic compounds. In addition, some crude oils also contain some amounts of aromatic and poly-aromatic compounds which, besides carbon and hydrogen, contain other atoms such as nitrogen, sulfur, and oxygen. While some poly-aromatic compounds that are oxidation inhibitors are beneficial, most are detrimental, since they often act as oxidation initiators and electrical charge carriers.