Diamond Dotted Paper (DDP)

Diamond Dotted Paper (DDP) is an insulation and bonding composite material for the core of oil immersed transformer windings, and is a high-frequency purchased insulation accessory in foreign trade.

Structure and Principle

Substrate: Electrical cable paper/cowhide insulation paper (conventional), aramid paper (high temperature resistant); The surface is coated with B-stage modified epoxy resin in a regular diamond grid pattern (non stick to the hand at room temperature, melted and solidified after heating)

Process logic: During the drying of the coil, the resin melts, sticks, and exhausts at a specific temperature (starting at 90 ℃, main curing at 125 ℃), and then thoroughly solidifies to bond the winding layer/turn into a rigid whole; Spot coating instead of full coating, reserved oil and exhaust channels to avoid corona and partial discharge

Insulation grade: common B/F grade, heat-resistant 130 ℃/155 ℃; The mechanical strength after curing is sufficient to resist interlayer displacement caused by short-circuit electric force

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