D connection structure of high-voltage coil of oil-immersed transformer

Abstract

The utility model discloses a D-connection structure for a high-voltage coil of an oil-immersed transformer, which is characterized in that the head end of an A-phase high-voltage coil is provided with a first head end joint, the tail end of the A-phase high-voltage coil is provided with a plurality of first tapping taps, the head end of a B-phase high-voltage coil is provided with a second head end joint, the tail end of the B-phase high-voltage coil is provided with a plurality of second tapping taps, the head end of a C-phase high-voltage coil is provided with a third head end joint, and the tail end of the C-phase high-voltage coil is provided with a plurality of third tapping The first head-end connector, the second head-end connector and the third head-end connector are correspondingly connected into a high-voltage sleeve on a transformer box cover in a penetrating mode, the first tapping taps, the second tapping taps and the third tapping taps are connected with corresponding static contacts on the tapping switch respectively, and the first head-end connector is connected with a lead of the third tapping tap located at the tail end. The second head end connector is connected with a first tapping tap located at the tail end through a lead, and the third head end connector is connected with a second tapping tap located at the tail end through a lead. According to the high-voltage coil D-connection structure, the length of the D-connection lead is greatly shortened, the anti-short-circuit capacity of the D-connection lead is improved, wiring operation is convenient, and economic benefits are good.

Description

Technical Field

[0001] This utility model relates to the field of transformer design technology, specifically to a D-connection structure for the high-voltage coil of an oil-immersed transformer. Background Technology

[0002] The high-voltage winding of a distribution transformer is split to adjust the output voltage to meet the voltage differences of the power grid lines. It changes the number of turns on one side to change the turns ratio between the primary and secondary sides, and ultimately changes the output voltage on the secondary side.

[0003] Currently, the existing oil-immersed distribution transformer connection group is Dyn11, and the corresponding three-phase high-voltage coil D-connection method is as follows: Figures 1-2 As shown, the iron core 7 is wound with an A-phase high-voltage coil, a B-phase high-voltage coil, and a C-phase high-voltage coil. The A-phase high-voltage coil has a starting connector a, and several taps 4 and a tail connector x at its starting end. The B-phase high-voltage coil has a starting connector b, and several taps 5 and y at its tail end. The C-phase high-voltage coil has a starting connector c, and several taps 6 and 3z at its tail end. The transformer tank cover 1 is equipped with a tap changer 3 and several high-voltage bushings 2. The starting connectors a, b, and... The first-end connector 3c is respectively connected to the high-voltage bushing 2 on the transformer box cover 1. Several tap 1 4, several tap 2 5 and several tap 3 6 are respectively connected to a set of corresponding stationary contacts on the tap changer 3. When the lead wire D is connected: the first-end connector 1a on the A-phase high-voltage coil is connected to the tail-end connector 3z on the C-phase high-voltage coil, the first-end connector 2b on the B-phase high-voltage coil is connected to the tail-end connector 1x on the A-phase high-voltage coil, and the first-end connector 3c on the C-phase high-voltage coil is connected to the tail-end connector 2y on the B-phase high-voltage coil. The problems with the D-connection method of the three-phase high-voltage coil of the oil-immersed distribution transformer are as follows: (1) Since the first end of the three-phase high-voltage coil is connected to the high-voltage bushing on the transformer tank cover, and several taps of the three-phase high-voltage coil are connected to the stationary contacts on the tap changer, and the first and last end of the three-phase high-voltage coil are D-connected at the coil position, the lead wire length used for the D-connection of the first and last end of the three-phase high-voltage coil is relatively long, which leads to a decrease in the short-circuit withstand capability of the lead wire, posing a hidden danger to the safe operation of the oil-immersed distribution transformer; (2) It is necessary to reserve an additional tail end connector at the tail end of the three-phase high-voltage coil, which is inconvenient for wiring and seriously restricts the assembly and processing efficiency of the oil-immersed distribution transformer. To this end, this utility model proposes a novel D-connection structure for the high-voltage coil of the oil-immersed transformer in order to solve the above-mentioned technical problems. Summary of the Invention

[0004] The purpose of this invention is to overcome the defects in the existing technology and provide a D-connection structure for the high-voltage coil of an oil-immersed transformer. By connecting the first end connector of the three-phase high-voltage coil to a corresponding tap lead at the tail end, the length of the D-connection lead is significantly shortened, while the short-circuit withstand capability of the D-connection lead is improved. Moreover, the connection operation of the D-connection lead is convenient, and there is no need to set a tail end connector at the tail end of the three-phase high-voltage coil. This helps to improve the overall assembly and processing efficiency of the oil-immersed distribution transformer and has good economic benefits.

[0005] To achieve the above objectives, the technical solution of this utility model is to design a D-connection structure for the high-voltage coil of an oil-immersed transformer, including a transformer tank cover and an iron core. The transformer tank cover is equipped with a tap changer and several high-voltage bushings. The iron core is wound with an A-phase high-voltage coil, a B-phase high-voltage coil, and a C-phase high-voltage coil. The A-phase high-voltage coil has a first-end connector at its starting end and several taps at its ending end. The B-phase high-voltage coil has a second-end connector at its starting end and several taps at its ending end. The C-phase high-voltage coil has a third-end connector at its starting end and several taps at its ending end. The three taps are connected to the high-voltage bushings on the transformer box cover. Each of the taps is connected to a set of corresponding stationary contacts on the tap changer. The tap 1 is connected to a lead of one of the taps at the tail end. The tap 2 is connected to a lead of one of the taps at the tail end. The tap 3 is connected to a lead of one of the taps at the tail end.

[0006] This utility model discloses a D-connection structure for the high-voltage coil of an oil-immersed transformer. By connecting the first end connector of the three-phase high-voltage coil to a corresponding tap lead located at the tail end, the length of the D-connection lead is significantly shortened, while the short-circuit withstand capability of the D-connection lead is improved. Furthermore, the connection operation of the D-connection lead is convenient, eliminating the need for an additional tail end connector at the tail of the three-phase high-voltage coil. This helps improve the overall assembly and processing efficiency of the oil-immersed distribution transformer, resulting in good economic benefits.

[0007] A preferred technical solution is that the first connector is connected to a corresponding tap three-lead wire at a position corresponding to the lower end of the corresponding high-voltage bushing; the second connector is connected to a corresponding tap one-lead wire at a position corresponding to the lower end of the corresponding high-voltage bushing; and the third connector is connected to a tap two-lead wire at a position corresponding to the lower end of the corresponding high-voltage bushing. This wiring operation is convenient and helps improve the D-connection efficiency between the three-phase high-voltage coils.

[0008] A preferred technical solution further includes connecting the first connector to a corresponding tap with a three-lead wire at a position corresponding to the tap switch; connecting the second connector to a corresponding tap with a one-lead wire at a position corresponding to the tap switch; and connecting the third connector to a corresponding tap with a two-lead wire at a position corresponding to the tap switch. The leads correspond to the tap switch positions, thus minimizing the lead length between the first connector and the corresponding tap, further reducing lead usage and saving lead resources.

[0009] The advantages and beneficial effects of this utility model are as follows:

[0010] This utility model discloses a D-connection structure for the high-voltage coil of an oil-immersed transformer. By connecting the first end connector of the three-phase high-voltage coil to a corresponding tap lead located at the tail end, the length of the D-connection lead is significantly shortened, while the short-circuit withstand capability of the D-connection lead is improved. Furthermore, the connection operation of the D-connection lead is convenient, eliminating the need for an additional tail end connector at the tail of the three-phase high-voltage coil. This helps improve the overall assembly and processing efficiency of the oil-immersed distribution transformer, resulting in good economic benefits. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the D-connection structure of the three-phase high-voltage coil of an existing oil-immersed transformer;

[0012] Figure 2 This is a schematic diagram of the connection structure of the three tap positions of an existing oil-immersed transformer.

[0013] Figure 3 This is a schematic diagram of the D-connection structure of a three-phase high-voltage coil of an oil-immersed transformer in Embodiment 1;

[0014] Figure 4 yes Figure 3 A magnified view of a section at point H in the middle;

[0015] Figure 5 This is a schematic diagram of the connection structure of the three tap positions of an oil-immersed transformer in Example 1.

[0016] In the diagram: 1. Transformer box cover; 2. High-voltage bushing; 3. Tap changer; 4. Tap tap one; 5. Tap tap two; 6. Tap tap three; 7. Iron core; a. First end connector one; b. First end connector two; c. First end connector three; x. Tail end connector one; y. Tail end connector two; z. Tail end connector three. Detailed Implementation

[0017] The specific embodiments of this utility model will be further described below with reference to the accompanying drawings and examples. The following examples are only used to more clearly illustrate the technical solution of this utility model and should not be construed as limiting the scope of protection of this utility model.

[0018] Example 1

[0019] like Figures 3-5 As shown, a high-voltage coil D-connection structure of an oil-immersed transformer includes a transformer tank cover 1 and an iron core 7. The transformer tank cover 1 is equipped with a tap changer 3 and several high-voltage bushings 2. The iron core 7 is wound with an A-phase high-voltage coil, a B-phase high-voltage coil, and a C-phase high-voltage coil. The A-phase high-voltage coil has a first-end connector a at its starting end and several taps 4 at its ending end. The B-phase high-voltage coil has a second-end connector b at its starting end and several taps 5 at its ending end. The C-phase high-voltage coil has a third-end connector c at its starting end and several taps 6 at its ending end. First-end connector a, first-end connector b, and first-end connector c are respectively connected to the high-voltage bushing 2 on the transformer box cover 1. Several taps 1 4, several taps 2 5, and several taps 3 6 are respectively connected to a set of corresponding stationary contacts on the tap changer 3. First-end connector a is connected to a lead wire of tap 3 6 located at the tail end. First-end connector b is connected to a lead wire of tap 1 4 located at the tail end. First-end connector c is connected to a lead wire of tap 2 5 located at the tail end.

[0020] This utility model discloses a D-connection structure for the high-voltage coil of an oil-immersed transformer. By connecting the first end connector of the three-phase high-voltage coil to a corresponding tap lead located at the tail end, the length of the D-connection lead is significantly shortened, while the short-circuit withstand capability of the D-connection lead is improved. Furthermore, the connection operation of the D-connection lead is convenient, eliminating the need for an additional tail end connector at the tail of the three-phase high-voltage coil. This helps improve the overall assembly and processing efficiency of the oil-immersed distribution transformer, resulting in good economic benefits.

[0021] Example 2

[0022] A D-connection structure for the high-voltage coil of an oil-immersed transformer differs from the D-connection structure for the high-voltage coil of an oil-immersed transformer in that: the first end connector a is connected from a position corresponding to the lower end of the corresponding high-voltage bushing 2 to a lead of the corresponding tap three 6; the second end connector b is connected from a position corresponding to the lower end of the corresponding high-voltage bushing 2 to a lead of the corresponding tap one 4; and the third end connector c is connected from a position corresponding to the lower end of the corresponding high-voltage bushing 2 to a lead of the corresponding tap two 5. This facilitates lead wiring and helps improve the D-connection efficiency between the three-phase high-voltage coils.

[0023] Example 3

[0024] A D-connection structure for the high-voltage coil of an oil-immersed transformer differs from the D-connection structure for the high-voltage coil of an oil-immersed transformer in that: the first-end connector a is connected from the position corresponding to the tap switch 3 to the lead of the corresponding tap three 6; the second-end connector b is connected from the position corresponding to the tap switch 3 to the lead of the corresponding tap one 4; and the third-end connector c is connected from the position corresponding to the tap switch 3 to the lead of the corresponding tap two 5. The leads correspond to the tap switch positions, thereby minimizing the lead length between the first-end connector and the corresponding tap, further reducing the amount of lead used and saving lead resources.

[0025] This utility model discloses a D-connection structure for the high-voltage coil of an oil-immersed transformer, which is applicable to transformers with different numbers of adjustment taps. For example, when the high-voltage tap is 5, each phase high-voltage coil has 6 taps: 2, 3, 4, 5, 6, and 7. The D-connection is as follows: the first terminal connector a of the A-phase high-voltage coil is connected to the 7# lead of the tap of the C-phase high-voltage coil at the tail end of the tap changer; the first terminal connector b of the B-phase high-voltage coil is connected to the 7# lead of the tap of the A-phase high-voltage coil at the tail end of the tap changer; and the first terminal connector a of the C-phase high-voltage coil is connected to the 7# lead of the tap of the B-phase high-voltage coil at the tail end of the tap changer.

[0026] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. A high-voltage coil D-connection structure for an oil-immersed transformer, comprising a transformer tank cover (1) and an iron core (7), wherein a tap changer (3) and several high-voltage bushings (2) are installed on the transformer tank cover (1), and an A-phase high-voltage coil, a B-phase high-voltage coil and a C-phase high-voltage coil are wound on the iron core (7), wherein the A-phase high-voltage coil has a first end connector (a) at its beginning end and several taps (4) at its end, and the B-phase high-voltage coil has a second end connector (b) at its beginning end and several taps (4) at its end. The first (5) and the first (c) of the C-phase high-voltage coil are provided with a first-end connector three and a plurality of taps three (6) at the tail end. The first (a), first (b) and first (c) connectors are respectively connected to the high-voltage bushings (2) on the transformer box cover (1). The plurality of taps one (4), taps two (5) and taps three (6) are respectively connected to a set of corresponding stationary contacts on the tap changer (3). The first end connector (a) is connected to a third tap (6) at the tail end, the second end connector (b) is connected to a first tap (4) at the tail end, and the third end connector (c) is connected to a second tap (5) at the tail end.

2. The D-connection structure of the high-voltage coil of the oil-immersed transformer as described in claim 1, characterized in that, The first end connector (a) is connected to a corresponding tap three (6) lead wire from the position corresponding to the lower end of the corresponding high-pressure bushing (2), the second end connector (b) is connected to a corresponding tap one (4) lead wire from the position corresponding to the lower end of the corresponding high-pressure bushing (2), and the third end connector (c) is connected to a corresponding tap two (5) lead wire from the position corresponding to the lower end of the corresponding high-pressure bushing (2).

3. The D-connection structure of the high-voltage coil of the oil-immersed transformer as described in claim 1, characterized in that, The first end connector (a) is connected from the position corresponding to the tap switch (3) to the lead of the corresponding tap three (6), the second end connector (b) is connected from the position corresponding to the tap switch (3) to the lead of the corresponding tap one (4), and the third end connector (c) is connected from the position corresponding to the tap switch (3) to the lead of the corresponding tap two (5).

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