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Views: 0 Author: Site Editor Publish Time: 2024-12-30 Origin: Site
Transformer insulation oil serves as a liquid insulating medium and heat‑transfer fluid widely used in power‑transmission equipment, including transformers, switchgear, rectifiers, cables, and capacitors. As a specialized liquid medium for oil‑immersed transformers, transformer insulation oil delivers superior insulation, thermal stability, oxidation stability, and electrical properties.
It withstands long‑term high‑voltage electric fields and effectively prevents internal faults such as arcing, discharge, and explosion, securing stable transformer operation. With growing power‑grid construction worldwide, transformer installation volumes keep rising, driving higher market demand for qualified transformer insulation oil.
Based on base‑oil sources, transformer insulation oil falls into four major categories: mineral oil, vegetable oil, silicone oil, and synthetic ester transformer oil.
Mineral oil transformer oil has been deployed in oil‑immersed transformers for nearly 100 years. Proven through decades of field operation, it remains the preferred insulating fluid for EHV and UHV large‑capacity power transformers.
For ultra‑high‑voltage transmission projects, mineral‑based transformer insulation oil provides reliable insulation against leakage current. Its outstanding thermal performance provides effective thermal control, dissipating massive heat generated during transformer operation and maintaining internal temperature within safe working ranges.
Vegetable oil transformer oil is produced from natural oil crops via pressing, fine‑refining, and targeted modification treatments. This variant of transformer insulation oil brings multiple competitive strengths:
Higher ignition point: Improved fire resistance when facing high‑temperature faults, lowering fire hazards for power assets.
Solid electrical performance: Builds dependable insulation barriers for live components and reduces short‑circuit risks.
Renewable raw‑material supply: Raw materials such as soybean and rapeseed are widely available, matching sustainable‑development goals.
Biodegradable properties: In case of accidental leakage, it degrades naturally without long‑term soil or water pollution.
Silicone‑based transformer insulation oil features good electrical insulation, high flash‑point, and low pour‑point, with viscosity less sensitive to temperature shifts. It is commonly adopted for small‑size transformers rated below 35 kV.
However, silicone oil shows weak stability under partial discharge or electric spark impacts. Its insulation performance degrades under repeated electrical shocks. Therefore, silicone oil transformer oil is mostly limited to applications under 35 kV with moderate operating‑temperature requirements.
Made from polyol‑ester base stocks, synthetic ester transformer insulation oil stands out for excellent biodegradability. Micro‑organisms can break it down into carbon dioxide and water in short cycles, creating minimal environmental harm. It is highly recommended for high‑eco‑requirement sites such as offshore wind farms.
Beyond eco‑friendliness, synthetic ester transformer insulation oil balances fire safety, electrical insulation, oxidation, and ageing resistance. Thanks to strong molecular polarity, it retains high breakdown voltage even under high‑moisture conditions, offering better moisture tolerance than mineral oil and silicone oil.
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The insulating function is core to transformer insulation oil. Filled inside transformer insulating structures, it physically isolates conductive parts operating at different potentials, blocks unwanted current flow, and raises overall equipment safety and reliability.
Transformers generate substantial heat during running cycles. Without effective heat removal, overheating and permanent equipment damage may occur.
Heated transformer insulation oil near windings and cores expands and rises due to lower specific gravity. After releasing heat via radiators or coolers, the cooled oil sinks back to the transformer tank bottom, forming continuous natural oil circulation. This circulating flow continuously cools windings and iron cores and optimizes transformer working conditions.
Commercial transformer insulation oil contains anti‑oxidant and anti‑corrosion additives. These additives mitigate corrosion and oxidation of internal metal components and extend overall transformer service life. Sealed oil‑filled structures also isolate internal components from ambient air and prevent harmful moisture ingress.
