Introduction to the transformer coil technology

This article mainly introduced the basic type of transformer coil, describes the four common types of structural characteristics and scope of application and the problems in design.

1. The introduction

Coil is transformer electrical components of the input and output power, is the most important and the most basic components, is also a major part of the transformer overhaul, with transformer "heart".Because it determines the basic capacity of transformer, voltage, current and conditions of use.

Coil form is mainly according to the size of the coil voltage level and capacity to choose, but also focus on electrical strength, the strength of heat resistant, mechanical strength, heat dissipation area and the possibility of manufacturing process, etc., to ensure that the manufacture or repair of transformer and reliable running.Generally for low voltage and large current coil, more commonly used around in root in parallel spiral coil, for the high voltage level, current is smaller, and on the longitudinal insulation and its special requirements often can be made continuous winding, intricate.

2, transformer coil structure

Due to the difference of transformer capacity and voltage, the structure characteristics of the coil is also each are not identical.Transformer coil is roughly divided into layer type and the bread type two kinds.Coil of wire turn along its axial direction according to the layer arranged in turn called coil;Coil of wire turn bread in the radial line (line), and then along the axial arrangement of bread called coil.Transformer coil form segment is as follows:

2.1 continuous coil

Continuous coil is one of the most common type of transformer coil.Continuous coil, divided into continuous and dual coil in a row.Continuous coil used in large and medium-sized transformers, voltage is 10 ~ 110 k Ⅴ high voltage, medium voltage and low voltage coil.Double continuous coil used in large and medium-sized transformer, voltage is 10 ~ 66 k Ⅴ medium voltage and low voltage coil.According to the needs of design, the coil end increase when necessary to protect small Angle ring, and use the molding protect horn ring, avoid the traditional tape type horn ring mechanical strength is insufficient to cause blockage phenomenon of oil.In order to improve the internal cooling coil, oil baffle plate can be set inside the coil, forced cooling oil flow according to set a good path, guarantee the cooling coil.For high voltage coil in order to improve the impact of the coil voltage distribution, according to the need to use shielded coil or entanglements coil.

2.2 in the coil

Shielding coil inside, it is single or multiple root in parallel insert some shielding turns in continuous line.Every insert number of turns of the line based on winding wave process calculation to determine.Shielding coil, divided into two segment across shielded coil within and across four shield type.Shielding coil inside such as connected to continuous coil, called the screen continuous coil.Shielding coil inside for flat wires and transposed conductor can be used, at the same time avoid the welding wire, reduce the welding head.

2.3 with the coil

With the structure of the coil and the difference between continuous, only lies in the order of the turn.It turns not to natural number sequence arrangement, but in the adjacent number sequence turns inserted between non-adjacent turn number sequence.This section of the line between the original continuous coil turns to use with transposition (rt), staggered remedy even formed with line, thus a tangle of coil.

With coil, divided into ordinary intricate and flower arranging intricate;Each is divided into two intricate and across the four sections across the intricate.With coil connected with continuous coil, called entangled with continuous coil.Common across two entangled with coil is often used in above 110 k Ⅴ and three-phase capacity < 90 m Ⅴ A transformer high voltage coil head end to strengthen or above 110 k Ⅴ and tapping of transformer high voltage, medium voltage coil.Entangled with common across four coil is often used in over 110 k Ⅴ and autotransformer regulating coil.Flower arrangement with coil is used only for special key products of high voltage coil end segment.With coil can more effectively improve the impulse voltage distribution within the coil, reduce the impulse voltage gradient, and entangled with coil anti-short circuit can better road.

2.4 a spiral coil

Spiral try to coil is mainly used for low voltage large current transformer voltage coil.Single (half), double spiral (half) a spiral coil is often used to contact below 35 kv transformer voltage low pressure coil or above 500 k Ⅴ and generator transformer high voltage coil Ⅱ in high - low - high structures (close to the core side high voltage coil);Double spiral, four spiral, spiral coil is often used in regulating the coil;Eight, ten spiral, spiral 16 spiral coil is often used in more than 500 k Ⅴ and autotransformer side column excitation regulating coil;Double spiral coil used in more than 110 k Ⅴ and low voltage of generator transformer coil, also calls the u-shaped coil and 220 k Ⅴ and above the low pressure axial double split transformer coil, also called double u-shaped coil.Parallel conductors with spiral coil number is more, generally the use of special rearrangement to reduce wire between the converter and the conductor transposition and padded with formed block the gap left in order to improve the resistance of the coil short circuit ability.In order to prevent the loose coil axial direction, the coil end use appropriate binding wire coil can be fixed.The coil end laminated damping is used to enhance the anti-short circuit ability and stability of the coil.

3, structural design should pay attention to the problem

(1) the intricate structure should reduce as far as possible or to screen continuous, because of the intricate compared with inner panel continuous welding head is more, complex operation, butt it polished after the easy generation metal dust, which has a certain influence on the transformer partial discharge.Switch to the screen after continuous, can reduce the craft difficulty, reduce a lot of wire welding head, can save about a third of the coil winding time, reduce a lot of hidden trouble at the same time;Intricate rectifying a composite wires in rectifying a conductor transposition of open, compared with the previous in even open the transposition can reduce welding position, and reduce the time, improve work efficiency.

(2) forming Angle outside outside the ring as far as possible not to have a cushion, add a lot of difficulties to process waste unnecessary time, to meet to, try to change the outer pad to pad between the layers, speed up the coil winding.

(3) the design of flower arranging rectifying structure must be important to consider the solder joints, avoid the process line of solder joints, affect the partial discharge of coil, increase the coil technology difficulty, a waste of time.

4, the conclusion

Above the basic model of transformer coil are analyzed and characteristics and scope of application, etc., and probes into the problems in the design analysis, hope to the transformer coil design personnel to provide reference.