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DDP (Diamond Dotted Paper) is primarily and most critically used in oil-immersed power transformers, especially as an interlayer and turn-to-turn insulation material for winding coils. It uniquely combines both insulation and bonding functions in one material.
During the drying and curing process of transformer coils, the resin coating on the surface of DDP melts and re-solidifies, firmly bonding adjacent coils into a unified structure. This significantly improves the winding’s ability to withstand electrodynamic forces generated during short circuits, preventing coil displacement or loosening and ensuring the long-term operational safety of the transformer.
Its core applications and functions can be summarized in the table below:
| Application Field | Specific Uses | Core Functions |
|---|---|---|
| Oil-immersed Transformers | Interlayer insulation, turn-to-turn insulation, conductor insulation | Bonds and fixes windings after curing, enhancing mechanical strength and short-circuit resistance |
| Other Power Equipment | Instrument transformers, reactors, etc. | Serves as general interlayer insulation, prevents component displacement, and ensures equipment safety |
| Special Transformers | Amorphous alloy transformers, high-overload transformers, etc. | Utilizes excellent thermal stability and mechanical properties to meet special design requirements |
The reason Diamond Dotted Paper performs so effectively in these applications lies in its unique design:
Diamond-pattern adhesive coating for better oil penetration
The epoxy resin is distributed in a diamond-dot pattern, providing smooth channels for transformer oil penetration and allowing gases to escape during coil drying. This effectively helps prevent corona discharge and partial discharge phenomena.
Thermal curing adhesion for stronger structure
Under high temperatures, the epoxy resin first melts to bond the windings and then cures into a solid structure, making the entire transformer winding more compact and mechanically stable. This greatly improves the transformer’s resistance to short-circuit impacts.
Multiple material options with selectable heat resistance
Depending on different thermal class requirements, the base material can be standard cellulose insulation paper or high-temperature-resistant aramid paper such as Nomex.
In summary, DDP insulation Paper is one of the key insulation materials used to improve the reliability and short-circuit resistance of oil-immersed transformers and other power equipment.
ZTelec Group is a professional transformer insulation material manufacturer. We provide one-stop customized insulation material solutions based on different transformer application scenarios. If you are looking for high-quality transformer insulation materials, please contact us for free product catalogs and quotations.
