CN215342277U

CN215342277U - Dry-type grounding transformer with adjustable zero-sequence impedance

Info

Publication number: CN215342277U
Application number: CN202121731376.1U
Authority: CN
Inventors: 邢广勤; 白杨; 张海旭
Original assignee: Shenyang Zhongbian Power Technology Co ltd
Current assignee: Shenyang Zhongbian Power Technology Co ltd
Priority date: 2021-07-28
Filing date: 2021-07-28
Publication date: 2021-12-28
Anticipated expiration: 2031-07-28

Abstract

The utility model belongs to the technical field of transformers, and particularly relates to a dry-type grounding transformer with adjustable zero-sequence impedance, which comprises an iron core, wherein the iron core comprises two E-shaped structures, a plurality of iron core cakes and a plurality of air gap structures, the two E-shaped structures are oppositely arranged, the iron core cakes and the air gap structures form 3 identical air gap structure-iron core cake complexes according to the arrangement mode of the air gap structures, the iron core cakes, … … and the air gap structures, and the air gap structure-iron core cake complexes are respectively connected between corresponding branches of the two E-shaped structures. The utility model can adjust the thickness of the iron core cake and the air gap structure in the design stage, thereby realizing the adjustment of the zero sequence impedance; secondly, when the transformer is used, the connection mode of the connection pieces is adjusted according to different use working conditions, so that the number of turns of the coil is adjusted, and zero-sequence impedance is adjusted in the use process.

Description

Dry-type grounding transformer with adjustable zero-sequence impedance

Technical Field

The utility model belongs to the technical field of transformers, and particularly relates to a dry-type grounding transformer with adjustable zero-sequence impedance.

Background

At present, a known dry-type grounding transformer has a fixed zero-sequence impedance value after production is finished, adjustment cannot be performed, and generally, zero-sequence impedance has a specific required value.

SUMMERY OF THE UTILITY MODEL

In order to solve the technical problems, the utility model provides the dry-type grounding transformer with adjustable zero-sequence impedance, which has the advantages of simple design, cost saving, simple structure and convenient operation, and the zero-sequence impedance value can be adjusted according to the system requirement after the production is finished.

The utility model is realized in this way, a dry-type grounding transformer with adjustable zero-sequence impedance comprises an iron core, wherein the iron core comprises two 'mountain' -shaped structures, a plurality of iron core cakes and a plurality of air gap structures, the two 'mountain' -shaped structures are oppositely arranged, the iron core cakes and the air gap structures form 3 identical air gap structure-iron core cake complexes according to the arrangement mode of the 'air gap structures, the iron core cakes, the air gap structures, the iron core cakes, … … and the air gap structures', and an air gap structure-iron core cake complex is respectively connected between corresponding branches of the two 'mountain' -shaped structures.

Preferably, the thickness of the air gap structure is 0.8-1.5 mm; the thickness of the iron core cake is 50 mm.

Further preferably, in the air gap structure-core cake composite, the number of the air gap structures is 5, and the number of the core cakes is 4.

Preferably, the air gap structure is made of an epoxy plate material.

Preferably, the coil structure further comprises 3 high-voltage coils, wherein the 3 high-voltage coils are respectively arranged on the branches of the delta-shaped structure and the periphery of the air gap structure-iron core cake complex, each high-voltage coil comprises 3 coils I and 3 coils II, each high-voltage coil is arranged according to the sequence of the coils I, the coils II, … …, the coils I and the coils II from top to bottom, the coil I at the uppermost end extends out of a first coil I leading-out head, the coil I at the lowermost end extends out of a second coil I leading-out head, and the two coils I which are closest to each other are connected through connecting leads between the sections of the coils I; the coil II at the uppermost end extends out of a first coil II leading-out head and 3 coil tapping taps, the coil II at the lowermost end extends out of a second coil II leading-out head, the coil II in the middle extends out of 3 coil tapping taps, and the coil II in the middle and the coil II at the lower end are connected through a connecting lead wire between II sections of the coil; a tapping sheet is arranged to connect one of the 3 coil tapping points extending from the coil II at the uppermost end with one of the 3 coil tapping points extending from the coil II at the middle end.

Preferably, the transformer further comprises 5 connecting guide rods, 3 high-voltage lead wires, an upper clamping piece and a lower clamping piece, wherein the 5 connecting guide rods and the 3 high-voltage lead wires are connected by a ZN connection method, and the first coil I leading-out head, the second coil I leading-out head, the first coil II leading-out head and the second coil II leading-out head of the 3 high-voltage coils are connected; the upper clamping piece and the lower clamping piece are fixedly arranged at the upper end and the lower end of the iron core respectively, 4 high-voltage outgoing line terminals are arranged on the upper clamping piece, and the 4 high-voltage outgoing line terminals are connected with the connecting guide rod and the high-voltage lead at corresponding positions respectively.

More preferably, a foot pad is provided at the bottom of the core.

Compared with the prior art, the utility model has the advantages that:

firstly, in a design stage, the thickness of an iron core cake and an air gap structure is designed and adjusted by adopting a design mode of the iron core cake with the air gap structure according to a preset value of a target transformer, so that the zero-sequence impedance is adjusted;

secondly, when the transformer is used, the connection mode of the connection pieces is adjusted according to different use working conditions, so that the number of turns of the coil is adjusted, and zero-sequence impedance is adjusted in the use process.

Drawings

Fig. 1 is a structural view of an iron core in a transformer provided by the present invention;

FIG. 2 is a diagram of a high voltage coil in a transformer according to the present invention;

fig. 3 is a schematic diagram of an overall front view structure of the transformer according to the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the utility model and are not intended to limit the utility model.

The calculation formula of the zero sequence impedance of the staggered grounding transformer is as follows:

in the formula Z₀-zero sequence impedance, Ω; x₀-zero sequence reactance, Ω; r-high voltage coil phase resistance, omega. Wherein:

wherein f-frequency, Hz; omega-number of turns per set of coils for high voltage; sigma D-equivalent magnetic leakage area, cm²(ii) a rho-Rockwell coefficient; k_x-a transverse reactance coefficient; e.g. of the type_z-the turn voltage, V/T; h_x-reactance height, cm.

Because the turn number of each set of coil of the omega-high voltage has great influence on the zero sequence impedance calculation value, the zero sequence impedance value of the transformer can be changed by adjusting the turn number.

The utility model introduces a design principle of the reactor, and the reactance value calculation formula of the reactor is as follows:

wherein l-inductance value, Ω; s_zEffective core cross-sectional area, cm²(ii) a n-the number of air gaps on the single-column iron core; delta-individual air gap height, cm.

In conclusion, the zero sequence impedance calculation formula of the grounding transformer is adjusted as follows:

i.e. the height or thickness delta of the air gap structure, affects the magnitude of the value of l and thus the value of the zero sequence impedance of the transformer. Therefore, according to the principle, the utility model designs the following technical scheme:

referring to fig. 1, the present invention provides a dry-type grounding transformer with adjustable zero-sequence impedance, which includes an iron core 3, wherein the iron core 3 includes two "hill" -shaped structures 301, a plurality of iron core cakes 302, and a plurality of air gap structures 303, the two "hill" -shaped structures 301 are disposed oppositely, the iron core cakes 302 and the air gap structures 303 form 3 identical air gap structure-iron core cake complexes according to the arrangement of the "air gap structures 303, the iron core cakes 302, the air gap structures 303, the iron core cakes 302, … …, and the air gap structures 303", and one air gap structure-iron core cake complex is connected between corresponding branches of the two "hill" -shaped structures 301.

That is, referring to formula (4), in the process of designing the transformer, the thickness δ of the air gap structure 303 is adjusted according to the preset value of the target transformer, so that the reactance value l of the transformer can be adjusted, and finally, the zero-sequence impedance of the transformer is adjusted.

According to the variation range of the zero sequence impedance of the transformer under the common working condition, as the optimization of the technical scheme, the thickness of the air gap structure 303 is 0.8-1.5 mm; the thickness of the core cake 302 is 50 mm.

Preferably, in this embodiment, in the air gap structure-core cake composite, there are 5

air gap structures

303 and 4 core cakes 302.

Preferably, the air gap structure 303 is made of epoxy plate material.

Referring to fig. 2 and 3, in order to adjust the zero-sequence impedance of the transformer during use, as an improvement of the technical solution, the transformer further includes 3 high-voltage coils 5, wherein the 3 high-voltage coils 5 are respectively disposed on the branches of the "gabled" structure 301 and the periphery of the air gap structure-core-cake complex, each high-voltage coil 5 includes 3 coils i 501 and 3 coils ii 502, each high-voltage coil 5 is arranged in the order of "coil i 501, coils ii 502, … …, coil i 501, and coil ii 502" from top to bottom, the coil i 501 at the uppermost end extends out of the first coil i lead 5011, the coil i 501 at the lowermost end extends out of the second coil i lead 5012, and the two coils i 501 closest to each other are connected by an inter-coil i-segment connecting lead 5013; the coil II 502 at the uppermost end extends out of a first coil II leading-out

head

5021 and 3 coil tapping taps 5022, the coil II 502 at the lowermost end extends out of a second coil II leading-out head 5023, the coil II 502 in the middle extends out of 3 coil tapping taps 5022, and the coil II 502 in the middle is connected with the coil II 502 at the lower end through a coil II section connecting lead 5024; a tap 8 is provided to connect one of the 3 coil taps 5022 protruding from the uppermost coil ii 502 with one of the 3 coil taps 5022 protruding from the middle coil ii 502.

The dry-type grounding transformer with adjustable zero-sequence impedance further comprises 5 connecting

guide rods

6, 3 high-voltage lead wires 4, an upper clamping piece 1 and a lower clamping piece 7, wherein the 5 connecting guide rods 6 and the 3 high-voltage lead wires 4 connect the first coil I leading-out head 5011, the second coil I leading-out head 5012, the first coil II leading-out head 5021 and the second coil II leading-out head 5023 of 3 high-voltage coils 5 according to a ZN connection method; the upper clamping piece 1 and the lower clamping piece 7 are respectively and fixedly installed at the upper end and the lower end of the

iron core

3, 4 high-voltage outgoing line terminals 2 are arranged on the upper clamping piece 1, and the 4 high-voltage outgoing line terminals 2 are respectively connected with the connecting guide rod 6 and the high-voltage lead 4 at corresponding positions.

First coil i tap 5011 is identified as a1 in the figure, second coil i tap 5012 is identified as X1 in the figure, first coil ii tap 5021 is identified as a2 in the figure, and second coil ii tap 5023 is identified as X2 in the figure; first coil I leading-out head 5011 and second coil I leading-out head 5012 of 3 high-voltage coils 5, first coil II leading-out head 5021 and second coil II leading-out head 5023 form ZN connection by utilizing 5 connecting

guide rods

6 and 3 high-voltage lead wires 4, and then are connected with external equipment. For stability and ease of connection, the connecting rod 6 and the high voltage lead 4 are stabilized on the upper clip 1 by the high voltage lead-out terminal 2, forming 4 connection positions labeled "0, A, B, C" in fig. 3.

3 coil tapping taps 5022 led out from the uppermost coil II 502 are respectively marked as 2, 4 and 6 in the figure, 3 coil tapping taps 5022 extending out from the middle coil II 502 are respectively marked as 7, 5 and 3 in the figure, five connection modes, namely 2 and 3 connection or 3 and 4 connection or 4 and 5 connection or 5 and 6 connection or 6 and 7 connection, are formed on one high-voltage coil through a splicing sheet 8, so that different numbers of turns are formed on each high-voltage coil, and the zero sequence impedance can be adjusted.

For convenience of installation, as a technical improvement, a foot pad 9 is arranged at the bottom of the iron core 3.

The embodiments of the present invention have been described in detail with reference to the drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge of those skilled in the art without departing from the gist of the present invention.

Claims

1. The dry-type grounding transformer with adjustable zero-sequence impedance is characterized by comprising an iron core (3), wherein the iron core (3) comprises two E-shaped structures (301), a plurality of iron core cakes (302) and a plurality of air gap structures (303), the two E-shaped structures (301) are arranged oppositely, the iron core cakes (302) and the air gap structures (303) form 3 identical air gap structure-iron core cake complexes according to the arrangement mode of the air gap structures (303), the iron core cakes (302), … … and the air gap structures (303), and one air gap structure-iron core cake complex is connected between corresponding branches of the two E-shaped structures (301).

2. The zero-sequence impedance adjustable dry grounding transformer of claim 1, wherein the thickness of the air gap structure (303) is 0.8-1.5 mm; the thickness of the iron core cake (302) is 50 mm.

3. The dry-type grounding transformer with adjustable zero-sequence impedance of claim 1, wherein the number of the air-gap structures (303) and the number of the core-cakes (302) in the air-gap structure-core-cake composite are 5 and 4 respectively.

4. The dry-type grounding transformer with adjustable zero-sequence impedance of claim 1, wherein the air gap structure (303) is made of epoxy board.

5. The zero-sequence impedance adjustable dry-type grounding transformer of claim 1 or 2 or 3 or 4, the coil structure is characterized by further comprising 3 high-voltage coils (5), wherein the 3 high-voltage coils (5) are respectively arranged on the branches of the mountain-shaped structure (301) and the periphery of the air gap structure-iron core cake complex, each high-voltage coil (5) comprises 3 coils I (501) and 3 coils II (502), each high-voltage coil (5) is arranged in sequence of the coils I (501), the coils II (502), … …, the coils I (501) and the coils II (502) from top to bottom, the coil I (501) at the uppermost end extends out of a first coil I leading-out head (5011), the coil I (501) at the lowermost end extends out of a second coil I leading-out head (5012), and the two coils I (501) closest to each other are connected through connecting leads (5013) between the coil I sections; the coil II (502) at the uppermost end extends out of a first coil II leading-out head (5021) and 3 coil tapping taps (5022), the coil II (502) at the lowermost end extends out of a second coil II leading-out head (5023), the coil II (502) in the middle extends out of 3 coil tapping taps (5022), and the coil II (502) in the middle and the coil II (502) at the lower end are connected through a coil II section connecting lead wire (5024); a tapping sheet (8) is arranged to connect one of the 3 coil tapping taps (5022) extending from the coil II (502) at the uppermost end with one of the 3 coil tapping taps (5022) extending from the coil II (502) in the middle.

6. The dry-type grounding transformer with adjustable zero-sequence impedance of claim 5, further comprising 5 connecting guide rods (6), 3 high-voltage leads (4), an upper clamping piece (1) and a lower clamping piece (7), wherein the 5 connecting guide rods (6) and the 3 high-voltage leads (4) connect the first coil I leading-out head (5011), the second coil I leading-out head (5012), the first coil II leading-out head (5021) and the second coil II leading-out head (5023) of the 3 high-voltage coils (5) according to a ZN connection method; an upper clamping piece (1) and a lower clamping piece (7) are respectively and fixedly installed at the upper end and the lower end of the iron core (3), 4 high-voltage outgoing line terminals (2) are arranged on the upper clamping piece (1), and the 4 high-voltage outgoing line terminals (2) are respectively connected with a connecting guide rod (6) and a high-voltage lead (4) at corresponding positions.

7. The dry-type grounding transformer with adjustable zero-sequence impedance of claim 5, wherein a foot pad (9) is provided at the bottom of the iron core (3).