Oil-immersed transformers, characterized by excellent heat dissipation, low losses, large capacity, and cost-effectiveness, have become the most widely used power transformers in power grids. Their reliability is directly tied to the safe and stable operation of power grids.
The thermal stability of insulation materials is a key factor influencing the service life and overload capacity of oil-immersed transformers. These transformers adopt a solid-liquid composite insulation structure, with the conventional oil-paper insulation system—composed of cellulose insulating paper and mineral insulating oil—being commonly used today. The safety and reliability of this insulation system form the fundamental basis for the normal operation of transformers.
Sui On Insulation provides a comprehensive range of insulation components and materials for transformers across small, medium, and large power ratings.
Commonly used insulation materials in oil-immersed transformers:
Insulating paper and board: Within the internal environment of oil-immersed transformers, these materials possess excellent heat resistance and electrical performance, making them ideal for manufacturing components such as insulating gaskets and bushings. Insulating paper (e.g., cable paper) is utilized for interlayer and turn-to-turn insulation of winding conductors, while insulating board (e.g., oil-impregnated board) serves applications like end support of windings, phase-to-phase insulation, and barrier insulation between high-voltage and low-voltage windings.
Sui On Insulation offers products including Miki kraft paper, NOMEX T910, and Nomex insulation paper processed parts. These products significantly enhance the insulation performance of materials after oil impregnation, while maintaining robust mechanical strength and flexibility.
DDP, Diamond Dot Paper, mainly consists of a base material (such as cable paper, polyester film, Nomex insulation paper or film) and a dot adhesive layer. The adhesive layer, primarily composed of thermosetting resins (like epoxy resin and phenolic resin), is printed onto the surface of the base material in a diamond grid pattern through a special process, hence the name derived from its diamond grid arrangement of adhesive dots. This material remains non-adhesive and dry at room temperature (below 35℃), boasting excellent insulation performance and stability. It is widely used for interlayer insulation in high-voltage equipment such as transformers and motors, effectively preventing breakdown and insulation failure.
The high-quality Soflex®BT diamond dot paper supplied by Sui On Insulation Company can bring customers of transformers multiple benefits in terms of economy, environment and safety. It not only helps reduce transformer weight, shrink equipment size and decrease the consumption of liquids like transformer oil, but also improves safety performance, lowers flammability, while increasing transformer capacity and reducing energy loss.
Crepe paper is a type of specialty paper with evenly distributed creases on its surface. Typically made from 100% pure imported pulp, it combines flexibility, insulation, and mechanical strength, thus being widely used in oil-immersed electrical transformers. The Nomex411 crepe paper supplied by Ruian Insulation can significantly enhance the insulating capability of materials for irregularly shaped parts in transformers.
In practical applications, liquid insulation (transformer oil) and solid insulation (paper, cardboard) typically form an "oil-paper" composite insulation system. Winding conductors, wrapped with insulating paper, are immersed in transformer oil: the insulating paper layers block partial discharges, while the oil fills gaps, creating a synergistic effect. This constitutes the most critical insulation form in oil-immersed transformers.
Sui On Insulation offers solutions for oil-immersed transformers, significantly enhancing overall insulation performance and heat resistance class to ensure the safe and stable operation of transformers.
