Different structure forms of transformer winding are selected according to the capacity and voltage. Common are as follows:
1. Cylindrical
It is a simple form of concentric winding. Good processability, easy winding, high heat dissipation efficiency of interlayer oil passage, but poor stability of end support. It is generally used for low-voltage winding with three-phase capacity of 630kVA and below and voltage of 1kV and below.
2. Segmented type
It is equivalent to dividing the multi-layer cylindrical winding into several line segments along the axial direction. Place insulating paper rings between line segments. This kind of winding can reduce the working voltage borne by interlayer insulation, but its manufacture is more complex than cylindrical type. It is applicable to the high-voltage winding of voltage transformer or high-voltage test transformer.
3. Continuous
It can adapt to the requirements of capacity and voltage in a large range. It has high mechanical strength and good heat dissipation performance, but it has high requirements for winding technology. One to six flat conductors are fixed on the insulating cylinder or placed on the brace of the winding die and wound into a pie shaped segment. The number of segments is usually even. The segments are separated by oil passages or staggered oil passages and paper rings. There are oil passages and insulating rings at both ends. It can be used for windings with three-phase capacity of 630kVA and above and voltage of 3 ~ 110kV. When oil passages and paper rings are staggered between sections, it can be used for windings with three-phase capacity of 630 ~ 6300KVA and voltage of 3 ~ 35kV.
4. Double cake type
Similar to the continuous type, it takes two line segments as a unit, that is, the so-called double cake. The double cakes are welded in series or parallel after the package. It is used for winding of electric furnace, rectifier and other special transformers with voltage of 35kV and below.
5. Tangled type
It is similar to the continuous type, but there are many welding joints. When the wire turn is composed of one wire, two wires shall be wound together. When two wires are connected in parallel, four wires shall be wound together. In order to increase the turn to turn capacitance of the winding and make the voltage distribution more reasonable when encountering overvoltage, the wire turns are not arranged in sequence, but connected by cross rectification. It can be used for windings with three-phase capacity of 6300KVA and above and voltage of 110 ~ 330kV.
6. Spiral type
The shape is similar to the continuous type, and one turn is equivalent to one section (single spiral type), two sections (double spiral type) or four sections (four spiral type) of the continuous type. The winding is simple, but due to the limitation of winding height, the winding with slightly more turns cannot be used. It can be used for high current winding with three-phase capacity of 800kVA and above and voltage of 35kV and below and voltage regulating winding of on load voltage regulating transformer.
7. Aluminum foil cylinder
It is similar to multi-layer cylindrical type, but each layer is one turn, and the width of aluminum foil is equal to the height of winding. This kind of winding has the advantages of good space utilization, automatic winding and high production efficiency. It can be used in small and medium-sized transformer windings.
