The transformer insulation treatment

The insulation treatment process of transformers is a key core link in transformer manufacturing, which directly determines the lifespan, reliability, and safety of transformers. The fundamental purpose is to establish a strong and reliable insulation barrier between the conductive parts of the transformer (such as windings, leads) and the grounding parts (such as iron cores, clamps), as well as conductive parts with different potentials, to withstand the electric field, heat, mechanical force, and environmental stress during operation.

The insulation treatment of transformers is mainly divided into two categories:

1.Insulation structure manufacturing: During the assembly process, various solid insulation materials are used to form physical isolation.

2.Insulation impregnation treatment: Use Varnish or Resin to impregnate, dry, and cure the assembled winding or entire body to form a sturdy whole.

The main purposes of insulation treatment include:

Electrical performance: Improve insulation strength, prevent partial discharge and electrical breakdown.

Mechanical properties: Solidify the winding, enhance mechanical strength, and resist deformation and wear caused by short-circuit electric force.

Thermal performance: Improve heat dissipation conditions, fill air gaps, and establish a good heat conduction path.

Environmental performance: prevents moisture, dust, and chemical pollutants from entering, enhances moisture resistance, corrosion resistance, and mold resistance.

Key insulation materials are divided into the following categories:

Solid insulation materials: including insulation paper (cable paper, telephone paper, heat-resistant paper), insulation cardboard (Pressboard), Nomex ® (Aramid paper), insulation laminated wood, epoxy glass cloth board, etc. are mainly used for winding interlayer, turn to turn, lead wrapping, support bars, cushion blocks, partition insulation in transformers.

Liquid insulation material: containing transformer oil (mineral oil, silicone oil, synthetic ester) mainly used to fill the entire oil tank as insulation and cooling medium

Impregnation materials: including insulation paint (with solvent paint, solvent-free paint), epoxy resin, polyester resin applied for winding impregnation and casting

The insulation treatment of transformers is far from simple "painting" or "oil soaking", it is a complex system engineering involving material science, vacuum technology, thermodynamics, and precision control. The long lifespan (25-30 years or more) and high reliability of modern transformers largely rely on these advanced and rigorous insulation treatment processes. Drying, impregnation, and curing are the core three steps that run through it, and the accuracy of each step directly affects the final performance of the transformer.

In the next chapter, we will elaborate on the processing technology of insulation materials for each component.  

 Want know more Details you could visit our website： www.transformer-home.com