CN215342259U - Grounding transformer with secondary winding - Google Patents
Grounding transformer with secondary winding Download PDFInfo
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- CN215342259U CN215342259U CN202121714015.6U CN202121714015U CN215342259U CN 215342259 U CN215342259 U CN 215342259U CN 202121714015 U CN202121714015 U CN 202121714015U CN 215342259 U CN215342259 U CN 215342259U
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- winding
- transformer
- secondary winding
- main
- grounding
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F27/00—Details of transformers or inductances, in general
- H01F27/24—Magnetic cores
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F27/00—Details of transformers or inductances, in general
- H01F27/28—Coils; Windings; Conductive connections
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F27/00—Details of transformers or inductances, in general
- H01F27/28—Coils; Windings; Conductive connections
- H01F27/30—Fastening or clamping coils, windings, or parts thereof together; Fastening or mounting coils or windings on core, casing, or other support
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F27/00—Details of transformers or inductances, in general
- H01F27/28—Coils; Windings; Conductive connections
- H01F27/32—Insulating of coils, windings, or parts thereof
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F27/00—Details of transformers or inductances, in general
- H01F27/34—Special means for preventing or reducing unwanted electric or magnetic effects, e.g. no-load losses, reactive currents, harmonics, oscillations, leakage fields
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F29/00—Variable transformers or inductances not covered by group H01F21/00
- H01F29/02—Variable transformers or inductances not covered by group H01F21/00 with tappings on coil or winding; with provision for rearrangement or interconnection of windings
- H01F29/04—Variable transformers or inductances not covered by group H01F21/00 with tappings on coil or winding; with provision for rearrangement or interconnection of windings having provision for tap-changing without interrupting the load current
Abstract
The utility model relates to a grounding transformer with a secondary winding, which comprises a transformer body, wherein the transformer body comprises: the transformer comprises an iron core, a main winding and a secondary winding, wherein the main winding is arranged on the outer side of the iron core, the secondary winding is arranged on the outer side of the main winding, and the main winding and the secondary winding are insulated from each other; the main winding comprises an inner winding and an outer winding, the inner winding and the outer winding are distributed in the radial direction of the transformer body, the inner winding and the outer winding are insulated from each other, and three phases with opposite polarities are connected in series to realize ZN connection; and the secondary windings are connected by yn. The main winding is arranged close to the iron core, zero sequence impedance can be reduced, the design requirement of 10 omega is met, and the grounding transformer has stronger capacity of tolerating short-circuit current when the system is in single-phase grounding; the secondary winding is arranged on the outer side of the main winding, so that the insulation distance between the main winding and the secondary winding can be freely adjusted on the premise of meeting the electrical strength, and the short-circuit resistance of the transformer is improved.
Description
Technical Field
The utility model relates to the technical field of transformers, in particular to a grounding transformer with a secondary winding.
Background
In the current power system, the low-voltage side of the main transformer is generally in a delta connection mode, and the operation mode that a neutral point is not grounded is adopted. When a single-phase fault occurs in an electric power system with an ungrounded neutral point, ferromagnetic resonance overvoltage and intermittent arc grounding overvoltage are easily generated, and then insulation damage and line tripping of a transformer are caused, so that the operation safety of a power grid is endangered. The grounding transformer can provide artificial neutral points for a power system with insulated neutral points, and the operation reliability of a power grid is improved. The windings of the common grounding transformer are generally composed of series windings connected in a zigzag manner (ZN connection), and the neutral point is led out and then is directly grounded or grounded through a grounding resistor and an arc suppression coil. If an auxiliary power supply needs to be added, a secondary winding can be added between the iron core and the series winding, but the zero-sequence impedance of the grounding transformer is large (30-50 omega), and when a single-phase grounding occurs in the power system, the capability of the grounding transformer for resisting short-circuit current is poor.
Therefore, how to provide a grounding transformer with a secondary winding, which has a smaller zero-sequence impedance and a stronger short-circuit resistance, is a technical problem to be solved urgently by those skilled in the art.
SUMMERY OF THE UTILITY MODEL
The utility model provides a grounding transformer with a secondary winding, which aims to solve the technical problem.
In order to solve the above technical problem, the present invention provides a grounding transformer with a secondary winding, comprising: a transformer body, the transformer body comprising: the transformer comprises an iron core, a main winding and a secondary winding, wherein the main winding is arranged on the outer side of the iron core, the secondary winding is arranged on the outer side of the main winding, and the main winding and the secondary winding are insulated from each other; the main winding comprises an inner winding and an outer winding, the inner winding and the outer winding are distributed in the radial direction of the transformer body, the inner winding and the outer winding are insulated from each other, and three phases with opposite polarities are connected in series to realize ZN connection; and the secondary windings are connected by yn.
Preferably, the main winding is provided with a 5-step tap.
Preferably, the head of the inner winding and the tap are led out upwards and connected with the first tap, the head of the outer winding and the tap are led out downwards and connected with the second tap, and the winding directions of the inner winding and the outer winding are opposite.
Preferably, the grounding transformer further comprises a combined tap switch, and an upper part and a lower part of the combined tap switch are respectively connected with the first tap line and the second tap line.
Preferably, the iron core is a three-phase three-column iron core.
Preferably, the main winding adopts a multi-layer cylindrical structure.
Preferably, the secondary winding adopts a single-layer cylindrical structure.
Compared with the prior art, the grounding transformer with the secondary winding has the following advantages:
1. the main winding is arranged close to the iron core, zero sequence impedance can be reduced, the design requirement of 10 omega is met, and the grounding transformer has stronger capacity of tolerating short-circuit current when the system is in single-phase grounding;
2. the secondary winding is arranged on the outer side of the main winding, so that the insulation distance between the main winding and the secondary winding can be freely adjusted on the premise of meeting the electrical strength, and the short-circuit impedance between the main winding and the secondary winding is ensured to meet the design requirement, thereby limiting the short-circuit current and improving the short-circuit resistance of the transformer.
3. The main winding comprises an inner winding and an outer winding, the inner winding and the outer winding are connected in series, the upper wire outlet and the lower wire outlet are opposite in winding direction, Z-shaped connection is realized through a combined tapping switch, and meanwhile, the voltage regulation function is met; the lead structure is simple, the operation is convenient, and the transformer body is simple and beautiful.
Drawings
FIGS. 1 and 2 are schematic diagrams of a grounding transformer with a secondary winding according to an embodiment of the present invention;
fig. 3 is a wiring diagram of the main winding in an embodiment of the present invention.
In the figure: 10-transformer body, 11-iron core, 12-inner winding, 13-outer winding, 14-secondary winding, 20-combined tap switch, 21-first tap wire and 22-second tap wire.
Detailed Description
In order to describe the technical solution of the above utility model in more detail, the following specific examples are given to demonstrate the technical effects; it is emphasized that these examples are intended to illustrate the utility model and are not to be construed as limiting the scope of the utility model.
The grounding transformer with secondary winding provided by the utility model is an oil-immersed grounding transformer, as shown in fig. 1 to 3, and comprises: a transformer body 10, the transformer body 10 comprising: the transformer comprises an iron core 11, a main winding and a secondary winding 14, wherein in the embodiment, the iron core 11 is a three-phase three-column iron core, the main winding is arranged on the outer side of the iron core 11, the secondary winding 14 is arranged on the outer side of the main winding, and the main winding and the secondary winding 14 are insulated from each other; the main winding comprises an inner winding 12 and an outer winding 13, the inner winding 12 and the outer winding 13 are distributed in the radial direction of the transformer body 10, the inner winding 12 and the outer winding 13 are mutually insulated, and three phases with opposite polarities are connected in series to realize ZN connection; the secondary winding 14 is connected by yn and can be used as an auxiliary power supply. The main winding is arranged close to the iron core 11, zero sequence impedance can be reduced, the design requirement of 10 omega is met, and the grounding transformer has stronger capacity of tolerating short-circuit current when the system is in single-phase grounding; the secondary winding 14 is arranged on the outer side of the main winding, so that the insulation distance between the main winding and the secondary winding 14 can be freely adjusted on the premise of meeting the electrical strength, and the designed value of the impedance voltage is controlled to be between 4% and 6%, thereby limiting the short-circuit current and improving the short-circuit resistance of the transformer.
Preferably, referring to fig. 1 and 2 with emphasis, the main winding is provided with 5-step taps for regulating the secondary side output voltage. Specifically, the head and the tap of the inner winding 12 are upward led and connected with the first tap 21, the head and the tap of the outer winding 13 are downward led and connected with the second tap 22, the winding directions of the inner winding 12 and the outer winding 13 are opposite, in this embodiment, the inner winding 12 is left-wound, and the outer winding 13 is right-wound. Preferably, the grounding transformer further includes a combined tap switch 20, wherein an upper portion and a lower portion of the combined tap switch 20 are respectively connected to the first tap line 21 and the second tap line 22, so as to implement a zigzag connection of the main windings connected in series by means of a cross-over connection, and simultaneously satisfy a voltage regulation function.
Preferably, the main winding adopts a multi-layer cylindrical structure, and the head, the tail and the tap are upper and lower axial outgoing lines; the secondary winding 14 is of a single-layer cylindrical structure. And a cylindrical structure is adopted, so that the winding is simple, and the impact voltage distribution is good.
In summary, the grounding transformer with a secondary winding provided by the present invention includes a transformer body 10, where the transformer body 10 includes: the transformer comprises an iron core 11, a main winding and a secondary winding 14, wherein the main winding is arranged on the outer side of the iron core 11, the secondary winding 14 is arranged on the outer side of the main winding, and the main winding and the secondary winding 14 are mutually insulated; the main winding comprises an inner winding 12 and an outer winding 13, the inner winding 12 and the outer winding 13 are distributed in the radial direction of the transformer body 10, the inner winding 12 and the outer winding 13 are mutually insulated, and three phases with opposite polarities are connected in series to realize ZN connection; the secondary winding 14 is connected by yn. The main winding is arranged close to the iron core 11, zero sequence impedance can be reduced, the design requirement of 10 omega is met, and the grounding transformer has stronger capacity of tolerating short-circuit current when the system is in single-phase grounding; the secondary winding 14 is arranged on the outer side of the main winding, so that the insulation distance between the main winding and the secondary winding 14 can be freely adjusted on the premise of meeting the electrical strength, and the short-circuit impedance between the primary winding and the secondary winding can meet the design requirement, thereby limiting the short-circuit current and improving the short-circuit resistance of the transformer.
It will be apparent to those skilled in the art that various changes and modifications may be made in the utility model without departing from the spirit and scope of the utility model. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.
Claims (7)
1. The utility model provides a grounding transformer with secondary winding which characterized in that, includes the transformer body, the transformer body includes: the transformer comprises an iron core, a main winding and a secondary winding, wherein the main winding is arranged on the outer side of the iron core, the secondary winding is arranged on the outer side of the main winding, and the main winding and the secondary winding are insulated from each other; the main winding comprises an inner winding and an outer winding, the inner winding and the outer winding are distributed in the radial direction of the transformer body, the inner winding and the outer winding are insulated from each other, and three phases with opposite polarities are connected in series to realize ZN connection; and the secondary windings are connected by yn.
2. The grounding transformer with secondary winding as recited in claim 1, wherein said main winding has 5 taps.
3. The grounding transformer with secondary winding as claimed in claim 2, wherein the head and tap of the inner winding are led out upward and connected to the first tap, the head and tap of the outer winding are led out downward and connected to the second tap, and the winding directions of the inner winding and the outer winding are opposite.
4. The grounding transformer with secondary winding as claimed in claim 3, wherein said grounding transformer further comprises a combination type tap switch, the upper and lower portions of which are connected to said first and second tap lines, respectively.
5. The grounding transformer with secondary winding as recited in claim 1, wherein said core is a three-phase three-limb core.
6. The grounding transformer with secondary winding as recited in claim 1, wherein said primary winding is in a multi-layer cylindrical configuration.
7. The grounding transformer with secondary winding as recited in claim 1, wherein said secondary winding is a single-layer cylindrical structure.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202121714015.6U CN215342259U (en) | 2021-07-27 | 2021-07-27 | Grounding transformer with secondary winding |
| PCT/CN2021/119243 WO2023004962A1 (en) | 2021-07-27 | 2021-09-18 | Grounding transformer comprising secondary winding |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202121714015.6U CN215342259U (en) | 2021-07-27 | 2021-07-27 | Grounding transformer with secondary winding |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN215342259U true CN215342259U (en) | 2021-12-28 |
Family
ID=79572678
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202121714015.6U Active CN215342259U (en) | 2021-07-27 | 2021-07-27 | Grounding transformer with secondary winding |
Country Status (2)
| Country | Link |
|---|---|
| CN (1) | CN215342259U (en) |
| WO (1) | WO2023004962A1 (en) |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3509507A (en) * | 1968-12-30 | 1970-04-28 | Westinghouse Electric Corp | Grounded y - y three-phase transformer |
| CN201600999U (en) * | 2010-02-09 | 2010-10-06 | 四川蜀能电器有限责任公司 | Grounding transformer capable of detecting zero sequence transformer |
| CN103310960A (en) * | 2013-06-17 | 2013-09-18 | 国家电网公司 | 66-kilovolt power distribution output grounding transformer for coil station |
| CN104425112B (en) * | 2013-09-04 | 2017-01-18 | 台达电子企业管理（上海）有限公司 | Transformer |
| CN204215865U (en) * | 2014-11-27 | 2015-03-18 | 山东泰开特变有限公司 | A kind of 20kV dry-type earth transformer |
| CN206774378U (en) * | 2017-05-05 | 2017-12-19 | 广州增变电气有限公司 | A kind of dry-type earth transformer |
-
2021
- 2021-07-27 CN CN202121714015.6U patent/CN215342259U/en active Active
- 2021-09-18 WO PCT/CN2021/119243 patent/WO2023004962A1/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| WO2023004962A1 (en) | 2023-02-02 |
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