CN101826391A - Segmented layered structure transformer - Google Patents

Abstract

The invention relates to a transformer with segmented layer structure, which includes a helical high-voltage coil winding and a low-voltage coil winding wound around the iron core, and is characterized in that a pair of taps are provided at both ends of the upper half of the high-voltage coil winding , the lower half is also provided with a pair of taps, the coil winding of the upper half is opposite to the coil winding of the lower half, the number of turns is the same, and the end tap of the upper half is connected with the beginning tap of the lower half. The invention can effectively solve the problem of reducing the interlayer voltage of the transformer coil winding, and reduce the influence of the interlayer voltage on the internal materials of the transformer, thereby improving the working stability of the transformer.

Description

Segmented Layer Structure Transformer

technical field

The invention relates to a segmented layer structure transformer, which is applied to a 35KV power supply system.

Background technique

Transformer 35kV power supply system commonly used connection method Yyn0, this connection method will cause output current asymmetry in the case of asymmetric load on the secondary side, resulting in neutral point drift on the primary side. Therefore, in response to the requirements of the power supply department, a design scheme of Dyn11 for the 35kV level connection was produced. The conventional design of the D-connection of the 35kV high-voltage coil is a common layer structure. Because the phase voltage of each phase coil is high and the number of turns is large, a high interlayer working voltage is generated. Insulation media such as transformer oil are exposed to too high interlayer working voltage for a long time, which is prone to insulation aging, transformer oil decomposition to produce gas and partial discharge and other problems. Therefore, how to solve the above problems is the research object of the present invention.

Contents of the invention

The invention relates to a segmented layer structure transformer, and aims to design a transformer structure capable of reducing the working voltage between layers of the transformer.

The technical solution of the present invention is realized in the following way: a transformer with segmented layer structure, including a spiral high-voltage coil winding and a low-voltage coil winding wound around the iron core, characterized in that: the two upper half sections of the high-voltage coil winding Each end is provided with a pair of taps, and the lower half is also provided with a pair of taps. The coil winding of the upper half is opposite to the coil winding of the lower half, and the number of turns is the same. The end taps of the upper half are connected with the beginning taps of the lower half.

The invention can effectively solve the problem of reducing the interlayer voltage of the transformer coil winding, and reduce the influence of the interlayer voltage on the internal materials of the transformer, thereby improving the working stability of the transformer.

Description of drawings

Figure 1 is the basic principle diagram of the segmented layer structure transformer

Figure 2 is a structural diagram of the high-voltage coil of the segmented layer structure transformer

Figure 3 is a schematic diagram of the tap clamping of the lower half of the high-voltage coil of the segmented layer structure transformer

Figure 4 is a schematic diagram of the segmented layer structure transformer high voltage coil insulator structure (1)

Figure 5 is a schematic diagram of the segmented layer structure transformer high voltage coil insulator structure (2)

Figure 6 is a schematic diagram of the high-voltage coil winding of the segmented layer structure transformer

Figure 7 is a schematic diagram of the body assembly of the sub-layer structure transformer

Detailed ways

Referring to Fig. 1, Fig. 2, Fig. 3, Fig. 4, Fig. 5, Fig. 6 and Fig. 7, a segmented layer structure transformer includes a helical high-voltage coil winding and a low-voltage coil winding around the periphery of the iron core. The two ends of the upper half of the high-voltage coil winding are respectively provided with a pair of taps, and the lower half is also provided with a pair of taps. The taps at the beginning of the lower half are connected.

The lower half of the upper half of the high-voltage coil winding is provided with a number of terminal taps, which are correspondingly connected to the starting taps of the upper half of the lower half through the middle voltage regulating switch, so as to reduce the interlayer working voltage of the coil winding.

According to Figure 2, this new high-voltage coil structure has the following characteristics:

The main airway A1 from inside to outside is as follows: item ⑤ corrugated oil channel + item ⑥ cardboard + item ⑦ insulating oil channel + item ⑧ cardboard + item ⑨ corrugated oil channel, the minimum value of A1 is 20mm

The insulation H1 between the high-voltage coil and the core end is as follows from top to bottom: iron yoke insulation + item ④ paper ring + item ③ corner ring + item ② insulating end ring + item ① end insulation, and the minimum value of h1 is 35mm.

The middle insulation H2 is from top to bottom: item ⑩ end insulation + item (11) insulation end ring + item (12) angle ring + item (12) angle ring + item (11) insulation end ring + item ⑩ end insulation , the minimum value of H2 is 41mm.

Since the high-voltage coil has no ampere-turn at the height of H2, the ampere-turn distribution along the coil height is uneven, resulting in a transverse leakage magnetic field and related additional impedance. The short-circuit impedance should be corrected when designing the high-voltage coil.

The entire high-voltage coil does not use an electrostatic screen, but uses an angle ring to improve the electric field and improve the insulation strength.

The high-voltage coil is 35kV class, D connection, and the wire insulation is 0.45mm;

The high-voltage coil is a segmented layer structure, and the two parts are arranged up and down along the axial direction. The insulation structure of the upper and lower parts is symmetrical, but the winding direction is opposite.

Interlayer insulation: selected according to the interlayer working voltage, and should be properly strengthened;

The size and quantity of the axial oil passage are determined according to the temperature rise calculation;

The upper and lower parts are the same in the total number of turns and the distribution of turns, the size, quantity and placement of oil passages, and the selection of interlayer insulation.

Taps 2, 4, and 6 in the upper half are on the outermost layer, leading out radially; taps 3, 5, and 7 on the lower half are in the innermost layer, leading out axially.

The coil taps 3, 5, and 7 of the lower half of the high-voltage coil need to be clamped and fixed by wire clamps when the leads are assembled, see Figure 3 for details.

The structure of the high-voltage coil insulator is novel: Item ② The insulating end ring is made of pads of different lengths and widths pasted on both sides of the paper ring, see Figure 4 for details. Item ⑦ Insulating oil channel: Slots are made at both ends and in the middle to place corner rings, see Figure 5 for details.

The high and low voltage coil winding process, the biggest feature of winding high voltage coils is: the upper and lower parts are wound at the same time, and the winding sequence is: install the high voltage coil winding die on the winding machine and fix the wound low voltage coil on the high voltage wire Accurate position of the coil winding mold. According to the high-voltage coil structure diagram, install item ⑤ corrugated oil passage, item ⑥ cardboard, and item ⑦ insulation oil passage. Draw a line at half of the height of the entire high-voltage coil to determine the position of the corner ring in item (12), Install the upper and lower parts of the item (12) corner ring at the same time, and the item (11) insulation end ring grabs the upper and lower parts at the same time, and then lays item ⑨ corrugated oil channel, grabs the upper and lower parts and fixes the winding head respectively, (item ② item ③ item ④ It is not installed temporarily during the winding process. When the body is assembled, reassemble item ②item ③item ④), and install a temporary wooden spacer at the position of item ②item ③item ④ to retain its item ②item ③item④ In the original space, lay the item ① end insulation grip, and then the upper and lower parts are wound from both ends to the middle at the same time. After winding the specified number of turns, lay the item ⑩ end insulation. After winding the first layer, follow this method to complete the entire high-voltage coil. , see Figure 6 for details.

Claims (2)

1. segmented layered structure transformer, comprise the spiral helicine high-tension coil winding and the low-voltage coil winding that are wrapped in the iron core periphery, it is characterized in that: the two ends of described high-tension coil winding upper semisection respectively are provided with a pair of tap, lower semisection also is provided with a pair of tap, upper semisection coil windings and lower semisection coil windings are around to opposite, the number of turn is identical, and the terminal tap of upper semisection is connected with the tap of lower semisection top.

2. segmented layered structure transformer according to claim 1, it is characterized in that: the latter half of described high-tension coil winding upper semisection is provided with some terminal taps, by middle part tap changer and the corresponding connection of some tops tap that the first half of lower semisection is provided with, be beneficial to reduce the interlayer operating voltage of coil windings.

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