Knowledage About Dry-type Transformer

Dry-type transformers have the advantages of fire prevention, disaster prevention, and maintenance-free, and are widely used in various fields of national production. Unlike oil-immersed transformers that use oil-paper insulation, the insulation structure of dry-type transformers is formed by the combination of air and solid insulation materials, and it has richer diversity in material selection and insulation combination. Based on the analysis of the development history of dry-type transformers and the classification of insulation structures, this paper discusses the application locations and functional requirements of various insulation materials in dry-type transformers, and points out that low-cost, high breakdown field strength, good heat resistance and thermal conductivity, and environmentally friendly insulation materials are the development direction of insulation materials in dry-type transformers; the aging mechanism of the insulation structure of dry-type transformers composed of insulation materials is analyzed, and the thermal aging and electrical aging assessment methods and status are discussed; the development direction of the insulation structure of dry-type transformers in large capacity, high voltage, good environmental adaptability, and mixed insulation is prospected.

Dry-type transformers have the advantages of fire prevention, disaster prevention, and maintenance-free, and are widely used in load centers and various special occasions. Unlike liquid-immersed transformers, which use insulating liquid as the main medium for insulation and heat dissipation, dry-type transformers achieve insulation and heat dissipation through the combination of air and solid insulating materials. The breakdown field strength of air is low, about 1/10 of that of transformer oil, and is greatly affected by the environment. Therefore, solid insulating materials and the insulating structure composed of solid insulating materials and air insulation are the determining factors affecting the reliability and service life of dry-type transformers.