Dry-Type Transformer Core Structure & Winding Structural Performance
The overall structure of the dry-type transformer consists of two core components: a high-precision laminated silicon steel sheet iron core and a high-strength insulated coil assembly. The entire body adopts a scientific matching structure of core and windings, supplemented by professional insulation isolation, positioning support and anti-loosening fastening systems, achieving excellent electrical insulation performance, strong mechanical stability and long-term operational safety. An insulating isolation tube is installed between the high-voltage and low-voltage coils to form a reliable intermediate insulation barrier, effectively improving the longitudinal electrical insulation strength between windings and avoiding inter-coil discharge risks caused by voltage stress concentration. Meanwhile, customized insulating cushion blocks are used for overall support and positioning constraint of the coils, ensuring compact internal structure, uniform stress distribution and no displacement or deformation under long-term operation or short-circuit impact conditions. All fasteners at structural overlapping positions are equipped with professional anti-loosening structures, which can effectively resist mechanical vibration and electromagnetic impact during equipment operation, preventing structural loosening and ensuring long-term overall structural stability of the transformer.
Classification and Performance Analysis of Winding Encapsulation Structure
According to different insulation encapsulation processes, transformer windings are divided into two mainstream structural types: solid insulation encapsulated winding and unencapsulated winding, which are applicable to different voltage levels, capacity ranges and operating scenarios respectively.
1. Solid Insulation Encapsulated Winding
The solid encapsulated winding adopts high-purity epoxy resin integral pouring and curing molding technology. The coil is completely wrapped by high-performance insulating resin, forming an integrated solid insulation structure. This structure features high mechanical strength, strong anti-deformation ability, excellent moisture-proof and dust-proof performance, and ultra-low partial discharge value. It can effectively resist external humidity, dust pollution and salt fog erosion, and will not generate insulation cracks or aging defects under long-term temperature cycle changes. With outstanding voltage resistance and impact resistance, it is very suitable for high-voltage, large-capacity and harsh-environment power distribution scenarios.
2. Unencapsulated Winding
The unencapsulated winding adopts open dry-type insulation structure without epoxy resin pouring. It is usually matched with high-grade heat-resistant insulating materials such as NOMEX paper, and undergoes multiple VPI vacuum pressure impregnation and high-temperature curing processes. This structure has the advantages of unobstructed internal heat dissipation, low operating temperature rise, strong overload capacity and excellent environmental degradability. It features green and environmentally friendly performance, no toxic gas release in extreme environments, and is easy to disassemble and recycle after service life, which is in line with modern green power grid construction standards.
High and Low Voltage Winding Configuration & Layout Design
Transformer windings are divided into high-voltage windings and low-voltage windings according to rated operating voltage levels. Among the two sets of matched windings, the winding with higher rated withstand voltage and input voltage is defined as the high-voltage winding, while the one with lower voltage grade and direct load power supply is the low-voltage winding. The reasonable voltage matching and structural coordination of the two windings determine the transformer's voltage conversion efficiency, load capacity and operational stability.
According to the relative assembly position and structural layout of high and low voltage windings, the winding layout is mainly divided into concentric structure and overlapping structure, with different application orientations and structural advantages.
Concentric Winding Structure (Mainstream Standard Structure)
The concentric winding structure arranges the high-voltage winding and low-voltage winding in a concentric nested form. The low-voltage winding is placed on the inner side close to the iron core, and the high-voltage winding is arranged on the outer side. This classic structural design features simple layout, neat internal structure, convenient manufacturing and processing, and high production consistency. It can form uniform electric field distribution, effectively reduce internal magnetic leakage and electromagnetic loss, and has excellent short-circuit resistance and operational stability. It is the standard structural solution widely adopted in conventional distribution dry-type transformers, covering most industrial, commercial and municipal power supply projects.
Overlapping Winding Structure (Special Customized Structure)
Different from the conventional concentric nested layout, the overlapping winding adopts a segmented cross-overlapping structural form. This special design can optimize the impulse voltage distribution and improve the lightning impact resistance and transient voltage stability of the transformer. However, it has complex manufacturing processes, high processing accuracy requirements and low production efficiency. Therefore, it is mostly customized for special-purpose transformers, high-impulse-resistant power supply equipment and special industrial power distribution scenarios with extreme voltage stability requirements, and is not used for conventional mass-produced distribution transformers.