CN216648017U - Photovoltaic plant boost transformer wiring form for inhibiting 5 and 7 harmonics - Google Patents
Photovoltaic plant boost transformer wiring form for inhibiting 5 and 7 harmonics Download PDFInfo
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- CN216648017U CN216648017U CN202122704730.8U CN202122704730U CN216648017U CN 216648017 U CN216648017 U CN 216648017U CN 202122704730 U CN202122704730 U CN 202122704730U CN 216648017 U CN216648017 U CN 216648017U
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Abstract
The utility model discloses a photovoltaic factory boosting transformer wiring form for inhibiting 5 and 7 subharmonics, which comprises a transformer, wherein the transformer comprises an iron core, a high-voltage side winding, a first low-voltage side winding and a second low-voltage side winding, the first low-voltage side winding adopts a triangular wiring form, and the second low-voltage side winding adopts a star-shaped wiring form; the transformer adopts a D/D0-y1 wiring form, 3n harmonics can be limited in the high-voltage side winding, so that the 3n harmonics sent into a power grid are reduced, and meanwhile, 5 and 7 harmonic components generated by the frequency converters connected with the two low-voltage side windings can be offset in the high-voltage side winding, so that the content of the 5 and 7 harmonics output to a current collection circuit by the high-voltage side winding is reduced; the utility model has simple wiring form and obvious offset effect.
Description
Technical Field
The utility model relates to the technical field of transformer wiring forms, in particular to a photovoltaic plant boosting transformer wiring form for inhibiting 5 th and 7 th harmonics.
Background
A large number of frequency converters are adopted below the photovoltaic field boosting transformer, so that generated harmonic waves are serious, a large number of filters are arranged on a current collection circuit 35kV bus in order to counteract the harmonic waves in photovoltaic power stations in many areas at present, and the cost is very high due to the fact that a large number of filters need to be arranged; if the connection form of D/D0-D6 is adopted, although two triangular connection forms with opposite phases are adopted, so that partial harmonics generated by the frequency converter are mutually cancelled in the iron core of the transformer to play a certain role in reducing the harmonics, the harmonics of 5 th order and 7 th order are still output to the current collecting circuit, and the content of the harmonics of 5 th order and 7 th order in the current collecting circuit is high.
SUMMERY OF THE UTILITY MODEL
The utility model aims to: aiming at the problem that the 5 th harmonic and the 7 th harmonic which are input into a current collecting circuit in the current boosting transformer are high in content, a photovoltaic plant boosting transformer wiring form for restraining the 5 th harmonic and the 7 th harmonic is provided, and the problem that the 5 th harmonic and the 7 th harmonic of the current collecting circuit are high in content is solved.
The technical scheme of the utility model is as follows:
a photovoltaic factory boosting transformer wiring form for inhibiting 5 and 7 harmonics comprises a transformer, wherein the transformer adopts an axial structure transformer; the transformer comprises an iron core, a high-voltage side winding, a first low-voltage side winding and a second low-voltage side winding, when the transformer is arranged, in order to offset 5 and 7 harmonics generated by the frequency converter, 2 valve side windings of the transformer are symmetrical left and right, namely the first low-voltage side winding and the second low-voltage side winding are symmetrically arranged, and the specific arrangement form is shown in figure 2.
Further, the first low-voltage side winding is in a delta connection form, and the second low-voltage side winding is in a star connection form; the 3n harmonic can be limited in the high-voltage side winding like the connection form of D/D0-D6, so that the 3n harmonic sent into the power grid is reduced, and because the output frequencies of the inverters connected in the same system in normal operation are the same, the harmonic waves generated by the frequency converters are approximately the same; when the first low-voltage side winding adopts a delta connection form and the second low-voltage side winding adopts a star connection form; the harmonic components of 5 th order and 7 th order generated by the frequency converter connected with the two low-voltage side windings can be counteracted at the high-voltage side winding, so that the content of the harmonic components of 5 th order and 7 th order output to a current collecting line by the high-voltage side winding is reduced.
Further, the first low voltage side winding and the second low voltage side winding are symmetrically arranged, as shown in fig. 2; the transformer adopts a wiring form of D/D0-y 1.
Further, the high-voltage side winding adopts a triangular connection mode, specifically, an outlet terminal a in the high-voltage side winding is connected with a neutral outlet terminal Y in the high-voltage side winding, an outlet terminal B in the high-voltage side winding is connected with a neutral outlet terminal Z in the high-voltage side winding, and the connection mode is as shown in a connection schematic diagram of the high-voltage side winding in fig. 1.
Furthermore, the outlet terminal a1 of the first low-voltage side winding is connected to the neutral outlet terminal y of the first low-voltage side winding, and the outlet terminal b1 of the first low-voltage side winding is connected to the neutral outlet terminal z of the first low-voltage side winding, as shown in the schematic connection diagram of the first low-voltage side winding in fig. 1.
Further, the second low-voltage side winding is in a star connection mode, and the specific connection mode is shown in a connection schematic diagram of the second low-voltage side winding in fig. 1.
The utility model is based on the following principle:
taking the primary side fundamental wave current phase of the split-core transformer as a reference, if the secondary side fundamental wave current phase of the transformer lags alpha, the 3-order harmonic current phase of the secondary side lags 3a, and the 3-order harmonic current phase of the primary side lags 3 a; the secondary side 5-order harmonic current has phase lag of 5a, and the primary side 5-order harmonic current has phase lag of 5a + a which is 6 a; the secondary 7 th harmonic current is phase-delayed by 7a and the primary 7 th harmonic current is phase-delayed by 7 a-6 a. When a is 30 degrees, 6a is 180 degrees, the primary sides just cancel each other according to formula GB14549-1993 power quality public grid harmonic C4, and the split transformer can be classified as D/y1 (11).
Further, from the point of view of transformer manufacture, the low voltage side has 2 windings of the same configuration, out of phase by 30 electrical degrees, which can have 2 different configurations: a radial configuration and an axial configuration; the radial structure has 3 different forms, as shown in fig. 3, and the axial structure has 2 different forms, as shown in fig. 4; in order to counteract the harmonic waves generated by the frequency converter as much as possible, the 2 valve side windings of the transformer are symmetrical and identical as much as possible; because the low-voltage side windings of the radial structure transformer have different structures (the impedance to the high-voltage side and the respective internal resistances of the two low-voltage windings are different), the photovoltaic step-up transformer should adopt an axial structure rather than a radial structure.
Compared with the prior art, the utility model has the beneficial effects that:
1. a photovoltaic factory boosting transformer wiring form for suppressing 5 th and 7 th harmonics comprises a transformer, wherein the transformer comprises an iron core, a high-voltage side winding, a first low-voltage side winding and a second low-voltage side winding, the first low-voltage side winding is in a triangular wiring form, and the second low-voltage side winding is in a star wiring form; the transformer adopts a wiring form of D/D0-y1, the wiring form of D/D0-y1 can limit 3n harmonics in a high-voltage side winding like the wiring form of D/D0-D6, so that the 3n harmonics sent into a power grid are reduced, and simultaneously, because the output frequencies of inverters connected in the same system in normal operation are the same, the harmonics generated by all frequency converters are approximately the same; when the first low-voltage side winding adopts a delta connection form and the second low-voltage side winding adopts a star connection form; the harmonic components of 5 th order and 7 th order generated by the frequency converter connected with the two low-voltage side windings can be counteracted at the high-voltage side winding, so that the content of the harmonic components of 5 th order and 7 th order output to a current collecting line by the high-voltage side winding is reduced.
Drawings
FIG. 1 is a schematic diagram of a photovoltaic plant boost transformer wiring form for suppressing 5, 7 th harmonics;
FIG. 2 is a schematic diagram of a transformer applied in the form of a photovoltaic plant boost transformer line for suppressing 5 th and 7 th harmonics;
FIG. 3 is a schematic diagram of a transformer with 3 kinds of radial structures and 2 low-voltage windings;
fig. 4 is a schematic diagram of a 2-axial structure transformer having 2 low voltage windings;
FIG. 5 is a wiring diagram of a photovoltaic plant boost transformer wiring form for suppressing 5 th and 7 th harmonics, which is applied to a 35kV photovoltaic power station.
Reference numerals: 11-iron core, 12-high voltage side winding, 13-first low voltage side winding, 14-second low voltage side winding.
Detailed Description
It is noted that relational terms such as "first" and "second," and the like, may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
The features and properties of the present invention are described in further detail below with reference to examples.
Example one
Referring to fig. 1-3, a photovoltaic plant boost transformer wiring form for suppressing 5, 7 th harmonics includes a transformer, which adopts an axial structure transformer; the transformer comprises an iron core 11, a high-voltage side winding 12, a first low-voltage side winding 13 and a second low-voltage side winding 14, and when the transformer is arranged, in order to offset 5 th and 7 th harmonics generated by the frequency converter, 2 valve side windings of the transformer are symmetrical left and right, namely the first low-voltage side winding 13 and the second low-voltage side winding 14 are symmetrically arranged, and the specific arrangement form is shown in fig. 2.
The first low-voltage side winding 13 adopts a delta connection form, and the second low-voltage side winding 14 adopts a star connection form; the 3n harmonic can be limited in the high-voltage side winding 12 like the connection form of D/D0-D6, so that the 3n harmonic sent into the power grid is reduced, and because the output frequencies of the inverters connected in the same system in normal operation are the same, the harmonic waves generated by the frequency converters are approximately the same; when the first low voltage side winding 13 takes a delta connection form and the second low voltage side winding 14 takes a star connection form; the harmonic components of 5 th order and 7 th order generated by the frequency converter connected with the two low-voltage side windings can be counteracted at the high-voltage side winding 12, so that the content of the harmonic components of 5 th order and 7 th order output to a current collecting line by the high-voltage side winding 12 is reduced.
Example two
Second embodiment is a further description of the first embodiment, the same components are not described again, please refer to fig. 1-3, the first low voltage side winding 13 and the second low voltage side winding 14 are symmetrically arranged, as shown in fig. 2; the transformer adopts a wiring form of D/D0-y 1.
The high-voltage side winding 12 is in a delta connection form, specifically, an outlet terminal a in the high-voltage side winding 12 is connected with a neutral outlet terminal Y in the high-voltage side winding 12, and an outlet terminal B in the high-voltage side winding 12 is connected with a neutral outlet terminal Z in the high-voltage side winding 12, as shown in a connection schematic diagram of the high-voltage side winding 12 in fig. 1.
Outlet terminal a1 of first low-voltage side winding 13 is connected to neutral point outlet terminal y of first low-voltage side winding 13, and outlet terminal b1 of first low-voltage side winding 13 is connected to neutral point outlet terminal z of first low-voltage side winding 13, as shown in the schematic wiring diagram of first low-voltage side winding 13 in fig. 1.
The second low voltage side winding 14 is in the form of a star connection, which is shown in fig. 1 as a schematic connection of the second low voltage side winding 14.
The utility model is based on the following principle:
taking the primary side fundamental wave current phase of the split-core transformer as a reference, if the secondary side fundamental wave current phase of the transformer lags alpha, the 3-order harmonic current phase of the secondary side lags 3a, and the 3-order harmonic current phase of the primary side lags 3 a; the secondary side 5-order harmonic current has phase lag of 5a, and the primary side 5-order harmonic current has phase lag of 5a + a to 6 a; the secondary 7 th harmonic current is phase-delayed by 7a and the primary 7 th harmonic current is phase-delayed by 7 a-6 a. When a is 30 degrees, 6a is 180 degrees, the primary sides just cancel each other according to formula GB14549-1993 power quality public grid harmonic C4, and the split transformer can be classified as D/y1 (11).
EXAMPLE III
In the third embodiment, the same components are not described again, and referring to fig. 1 to 3, from the perspective of transformer manufacturing, 2 windings with the same structure and 30 ° phase difference in electrical angle on the low-voltage side may have 2 different structures: a radial configuration and an axial configuration; while the radial structure has 3 different forms, as shown in fig. 3, the axial structure has 2 different forms, as shown in fig. 4.
In order to counteract the harmonic waves generated by the frequency converter as much as possible, the 2 valve side windings of the transformer are symmetrical and identical as much as possible; because the low-voltage side windings of the radial structure transformer have different structures (the impedance to the high-voltage side and the respective internal resistances of the two low-voltage windings are different), the photovoltaic step-up transformer should adopt an axial structure rather than a radial structure.
FIG. 5 is a schematic wiring diagram of a photovoltaic plant boost transformer wiring form for suppressing 5 th and 7 th harmonics, which is applied to a 35kV photovoltaic power station.
The above-mentioned embodiments only express the specific embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present application. It should be noted that, for those skilled in the art, without departing from the technical idea of the present application, several changes and modifications can be made, which are all within the protection scope of the present application.
Claims (8)
1. A photovoltaic plant boost transformer wiring form for suppressing 5, 7 th harmonics comprises a transformer, wherein the transformer comprises an iron core (11), a high-voltage side winding (12), a first low-voltage side winding (13) and a second low-voltage side winding (14), and is characterized in that the first low-voltage side winding (13) adopts a triangular wiring form, and the second low-voltage side winding (14) adopts a star-shaped wiring form;
the harmonic components of 5 th order and 7 th order generated by the frequency converter connected with the first low-voltage side winding (13) and the second low-voltage side winding (14) are counteracted in the high-voltage side winding (12).
2. The photovoltaic plant boost converter line form for suppressing sub5, 7 harmonics according to claim 1, characterized in that the first low voltage side winding (13) and the second low voltage side winding (14) are symmetrically arranged.
3. A photovoltaic plant step-up transformer form for suppressing sub-5, 7 harmonics according to claim 1, characterized in that the high-side winding (12) is in the form of a delta connection.
4. The photovoltaic plant boost converter wiring form for suppressing 5, 7 th harmonic according to claim 1, wherein the transformer is in the wiring form of D/D0-y 1.
5. The photovoltaic plant boost converter wiring form for suppressing sub5, 7 harmonics according to claim 1, characterized in that the outlet terminal a in the high-side winding (12) of the transformer is connected with the neutral outlet terminal Y in the high-side winding (12).
6. The photovoltaic plant boost converter line form for suppressing sub5, 7 harmonics according to claim 1, characterized in that the outlet terminal B in the high-voltage side winding (12) is connected with the neutral outlet terminal Z in the high-voltage side winding (12).
7. The photovoltaic plant boost converter line form for suppressing sub5, 7 harmonics according to claim 1, characterized in that the outlet terminal a1 of the first low voltage side winding (13) is connected with the neutral point outlet terminal y of the first low voltage side winding (13).
8. The photovoltaic plant boost converter line form for suppressing sub5, 7 harmonics according to claim 1, characterized in that the outlet terminal b1 of the first low voltage side winding (13) is connected with the neutral point outlet terminal z of the first low voltage side winding (13).
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202122704730.8U CN216648017U (en) | 2021-11-05 | 2021-11-05 | Photovoltaic plant boost transformer wiring form for inhibiting 5 and 7 harmonics |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202122704730.8U CN216648017U (en) | 2021-11-05 | 2021-11-05 | Photovoltaic plant boost transformer wiring form for inhibiting 5 and 7 harmonics |
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| CN216648017U true CN216648017U (en) | 2022-05-31 |
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| CN202122704730.8U Active CN216648017U (en) | 2021-11-05 | 2021-11-05 | Photovoltaic plant boost transformer wiring form for inhibiting 5 and 7 harmonics |
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| CN (1) | CN216648017U (en) |
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