A compact phase-shifting transformer and working system

Abstract

The present invention belongs to the field of transformer phase shifting and specifically discloses a compact phase-shifting transformer and operating system, comprising: an A-phase coil, a B-phase coil, a C-phase coil, an A-phase phase-shifting coil wound outside the A-phase coil, a B-phase phase-shifting coil wound outside the B-phase coil, and a C-phase phase-shifting coil wound outside the C-phase coil; the C-phase phase-shifting coil is connected to the same-name end A1 of the A-phase coil via a polarity conversion switch K1a, the A-phase phase-shifting coil is connected to the same-name end B1 of the B-phase coil via a polarity conversion switch K1b, and the B-phase phase-shifting coil is connected to the same-name end C1 of the C-phase coil via a polarity conversion switch K1c. The compact phase-shifting transformer of the present invention has a phase-shifting angle range of 0 to 12 degrees, which is more in line with the actual operating conditions of current power distribution networks. The 0-12° phase-shifting angle range ensures the use of delta-connected orthogonal phase shifting, greatly simplifying the structure of the phase-shifting transformer, reducing the size of the phase-shifting transformer, and lowering the manufacturing cost of the phase-shifting transformer.

Description

Technical Field

[0001] The present invention belongs to the technical field of transformer phase shifting, and in particular relates to a compact phase shifting transformer and a working system. Background Art

[0002] In order to achieve live line closing operation, a closing device is required to connect two 10kV lines (the first line L1 and the second line L2) with different phase angles to avoid additional power outages due to the inability to directly close the line.

[0003] In the existing technology, the 10kV ring closing device mainly adopts phase-shifting transformer. Figure 1 , its main phase shift principle is as follows:

[0004] 1. When the angle difference between two equal voltage phasors, U1 and U2, is θ, and θ ≤ 12°, the voltage difference between them can be approximated using ΔU ≈ U1 * tgθ. The theoretical value is 2 * U1 * SIN(θ / 2). When θ reaches a maximum of 12°, the maximum error between the two is (1 - 2 * Sin6 / tg12) * 100% = 1.65%. The smaller θ is, the smaller the error.

[0005] When θ=12°, ΔU≈U1*tg12=0.2126*U1

[0006] 2. The orthogonal vector sum of U1 and ΔU is U1 / Cosθ. When θ = 12°, this value is greater than U1 by (1-1 / Cos12)*100%=2.23%. The smaller θ is, the smaller the increase. When θ = 6°, this value is only greater than U1 by (1-1 / Cos6)*100%=0.55%. In other words, when θ ≤ 12°, the difference between the orthogonal vector sum of U1 and ΔU and U1 is very small.

[0007] Combining the above two points, when the angle difference between U1 and U2 is θ = 12°, the voltage difference between them is ΔU ≈ 0.213 * U1. If a phase-shift vector U3 = ΔU, orthogonal to U1, is added, then the vector sum of U1 and U3, U1 + U3, will be in phase with U2, and the maximum voltage difference between them and U2 will be only 0.0223 * U1, a 90% reduction from the pre-phase-shift value of ΔU = 0.213 * U1. Furthermore, the smaller θ is, the smaller the phase-shift vector U3 is, and the smaller the voltage difference between them and U2 is.

[0008] Chinese patent CN114999782A discloses a phase-shifting transformer for loop-closing power supply. This coil utilizes a zigzag connection for phase shifting and has three coils, making it difficult to achieve small-angle phase shifting and a relatively complex structure. Furthermore, Chinese patent CN215183483U discloses a phase-shifting transformer using a novel coil configuration. This coil also utilizes a delta connection for phase shifting and has three coils, but can only achieve fixed-angle phase shifting. Furthermore, Chinese patent CN116526476A discloses a 10KV live loop-closing operating device that utilizes a complex dual-body structure.

[0009] In summary, the prior art ignores the fact that the phase angle difference between the two lines in actual operating conditions is not large, and the designed phase shift angle is too large, resulting in a complex transformer structure, large size, and high production cost. Summary of the Invention

[0010] The present invention provides a compact phase-shifting transformer and a working system, which are used to solve the problem that small-angle phase shifting cannot be achieved currently.

[0011] In order to solve the above technical problems, the technical solution of the present invention is as follows: a compact phase-shifting transformer, comprising: an A-phase iron core leg, an A-phase coil wound on the A-phase iron core leg, a B-phase iron core leg, a B-phase coil wound on the B-phase iron core leg, a C-phase iron core leg, a C-phase coil wound outside the C-phase iron core leg, an A-phase phase-shifting coil wound outside the A-phase coil, a B-phase phase-shifting coil wound outside the B-phase coil, and a C-phase phase-shifting coil wound outside the C-phase coil;

[0012] The C-phase phase-shift coil is connected to the same-name end A1 of the A-phase coil through a polarity conversion switch K1a, the A-phase phase-shift coil is connected to the same-name end B1 of the B-phase coil through a polarity conversion switch K1b, and the B-phase phase-shift coil is connected to the same-name end C1 of the C-phase coil through a polarity conversion switch K1c.

[0013] In a preferred embodiment of the present invention, the A-phase phase-shifting coil, the B-phase phase-shifting coil, and the C-phase phase-shifting coil are arranged in the same manner.

[0014] In a preferred embodiment of the present invention, the A-phase phase shifting coil is provided with a plurality of A-phase taps, the A-phase taps are connected to the shift switch K2a, and the output end of the shift switch K2a is the terminal B2 after the B-phase coil is phase-shifted;

[0015] The B-phase phase shift coil is provided with a plurality of B-phase taps, which are connected to the shift switch K2b. The output end of the shift switch K2b is the terminal C2 after the phase shift of the C-phase coil.

[0016] The C-phase phase-shifting coil is provided with a plurality of C-phase taps, and the C-phase taps are connected to the gear-shifting switch K2c, and the output end of the gear-shifting switch K2c is the terminal A2 after the phase shift of the A-phase coil.

[0017] In a preferred embodiment of the present invention, the A-phase coil, the B-phase coil, and the C-phase coil are connected in a triangle shape.

[0018] In a preferred embodiment of the present invention, the number of taps on the A-phase phase-shifting coil is a factor of 12.

[0019] In a preferred embodiment of the present invention, the number of taps on the A-phase phase-shifting coil is 6.

[0020] In a preferred embodiment of the present invention, one end of the A-phase phase-shift coil is a positive terminal, and the other end is a negative terminal, and the polarity conversion switch K1a is connected to the positive terminal or the negative terminal; one end of the B-phase phase-shift coil is a positive terminal, and the other end is a negative terminal, and the polarity conversion switch K1b is connected to the positive terminal or the negative terminal; one end of the C-phase phase-shift coil is a positive terminal, and the other end is a negative terminal, and the polarity conversion switch K1c is connected to the positive terminal or the negative terminal.

[0021] In a preferred embodiment of the present invention, the like-name end of the A-phase phase-shift coil is connected to the negative pole of the polarity conversion switch K1a, and the opposite-name end of the A-phase phase-shift coil is connected to the positive pole of the polarity conversion switch K1a; the like-name end of the B-phase phase-shift coil is connected to the negative pole of the polarity conversion switch K1b, and the opposite-name end of the B-phase phase-shift coil is connected to the positive pole of the polarity conversion switch K1b; the like-name end of the C-phase phase-shift coil is connected to the negative pole of the polarity conversion switch K1c, and the opposite-name end of the B-phase phase-shift coil is connected to the positive pole of the polarity conversion switch K1c.

[0022] In a preferred embodiment of the present invention, the polarity conversion switch K1a, the polarity conversion switch K1b, and the polarity conversion switch K1c have the same connection polarity.

[0023] The present invention also discloses a working system of a transformer, which includes a compact phase-shifting transformer as described in any one of the items, a first line L1, and a second line L2; the output terminal A1 of the A-phase coil, the output terminal B1 of the B-phase coil, and the output terminal C1 of the C-phase coil of the compact phase-shifting transformer are connected to the first line L1, and the output terminal of the A-phase phase-shifting coil, the output terminal of the B-phase phase-shifting coil, and the output terminal of the C-phase phase-shifting coil are connected to the second line L2.

[0024] The technical solution provided by the present invention has the following advantages compared with the prior art:

[0025] The compact phase-shifting transformer in this invention has a phase-shifting angle range of 0 to 12°, which better matches the actual operating conditions of current power distribution networks. This 0-12° phase-shifting angle range enables the use of delta-connected orthogonal phase shifting, significantly simplifying the phase-shifting transformer structure, reducing its size, and lowering its manufacturing cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, without paying any creative work, they can also obtain drawings of other embodiments based on these drawings.

[0027] Figure 1 This is the phase shift principle diagram;

[0028] Figure 2 This is a coil connection principle diagram of a compact phase-shifting transformer according to one embodiment of the present invention;

[0029] Figure 3 Schematic diagram of coil arrangement and connection of a compact phase-shifting transformer and a working system according to one embodiment of the present invention. DETAILED DESCRIPTION

[0030] For ease of understanding, the compact phase-shifting transformer is described below in conjunction with embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0031] In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations and positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0032] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediary; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention.

[0033] To facilitate understanding of the present invention, the present invention will be described more fully below with reference to the accompanying drawings. The accompanying drawings illustrate preferred embodiments of the present invention. However, the present invention may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the present disclosure.

[0034] Reference Figure 2 and Figure 3 As shown, the present invention discloses a compact phase-shifting transformer, which includes: an A-phase iron core leg, an A-phase coil wound on the A-phase iron core leg, a B-phase iron core leg, a B-phase coil wound on the B-phase iron core leg, a C-phase iron core leg, a C-phase coil wound outside the C-phase iron core leg, an A-phase phase-shifting coil wound outside the A-phase coil, a B-phase phase-shifting coil wound outside the B-phase coil, and a C-phase phase-shifting coil wound outside the C-phase coil.

[0035] The C-phase phase-shift coil is connected to the same-name end A1 of the A-phase coil through the polarity conversion switch K1a, the A-phase phase-shift coil is connected to the same-name end B1 of the B-phase coil through the polarity conversion switch K1b, and the B-phase phase-shift coil is connected to the same-name end C1 of the C-phase coil through the polarity conversion switch K1c.

[0036] Specifically, refer to Figure 2 and Figure 3 , the same-named ends of each coil in the figure are marked with dots.

[0037] The same-name terminal of the A-phase phase-shift coil is connected to the negative pole of polarity conversion switch K1a, and the opposite-name terminal of the A-phase phase-shift coil is connected to the positive pole of polarity conversion switch K1a. The same-name terminal of the B-phase phase-shift coil is connected to the negative pole of polarity conversion switch K1b, and the opposite-name terminal of the B-phase phase-shift coil is connected to the positive pole of polarity conversion switch K1b. The same-name terminal of the C-phase phase-shift coil is connected to the negative pole of polarity conversion switch K1c, and the opposite-name terminal of the B-phase phase-shift coil is connected to the positive pole of polarity conversion switch K1c. Polarity conversion switches K1a, K1b, and K1c all have the same connection polarity.

[0038] Polarity switches K1a, K1b, and K1c are provided to connect the phase-shifting coil to the primary coil in two different vector directions. For example, when the A-phase phase-shifting coil and the A-phase phase-shifting coil are connected with opposite-polarity terminals, the phase shift angle is advanced; when the A-phase coil and the A-phase phase-shifting coil are connected with the same-polarity terminals, the phase shift angle is lagging. This allows for phase angle adjustment.

[0039] Specifically, the A-phase phase-shifting coil, the B-phase phase-shifting coil, and the C-phase phase-shifting coil are arranged in the same manner. Furthermore, the A-phase coil, the B-phase coil, and the C-phase coil are connected in a delta shape.

[0040] The A-phase phase-shifting coil is provided with multiple A-phase taps, which are connected to the gear-shifting switch K2a, and the output end of the gear-shifting switch K2a is the terminal B2 of the B-phase coil after phase shifting; the B-phase phase-shifting coil is provided with multiple B-phase taps, which are connected to the gear-shifting switch K2b, and the output end of the gear-shifting switch K2b is the terminal C2 of the C-phase coil after phase shifting; the C-phase phase-shifting coil is provided with multiple C-phase taps, which are connected to the gear-shifting switch K2c, and the output end of the gear-shifting switch K2c is the terminal A2 of the A-phase coil after phase shifting.

[0041] That is to say, the A-phase phase-shifting coil is used to set the shift switches K2a, K2b and K2c. Through the shift switches K2a, K2b and K2c, different taps on the A-phase phase-shifting coil can be selected, thereby achieving a phase shift within the range of ±12°, 12° / n per level, and a total of 2n different angles.

[0042] The number of taps on the A-phase phase-shifting coil is a factor of 12. In a preferred embodiment of the present invention, the number of taps on the A-phase phase-shifting coil is 6. Taking the A-phase phase-shifting coil as an example, the A-phase phase-shifting coil is typically provided with n taps, each corresponding to a phase shift angle of 12° / n. Different taps can be selected to achieve different phase shift angles. Where n is an integer divisible by 12, and n = 6 is typically used.

[0043] One end of the A-phase phase-shift coil is the positive terminal and the other end is the negative terminal, and the polarity conversion switch K1a is connected to the positive terminal or the negative terminal; one end of the B-phase phase-shift coil is the positive terminal and the other end is the negative terminal, and the polarity conversion switch K1b is connected to the positive terminal or the negative terminal; one end of the C-phase phase-shift coil is the positive terminal and the other end is the negative terminal, and the polarity conversion switch K1c is connected to the positive terminal or the negative terminal.

[0044] Reference Figure 3As shown, a transformer working system includes a compact phase-shifting transformer, a first circuit L1, and a second circuit L2. The output terminal A1 of the A-phase coil, the output terminal B1 of the B-phase coil, and the output terminal C1 of the C-phase coil of the compact phase-shifting transformer are connected to the first circuit L1, and the output terminal B2 of the A-phase phase-shifting coil, the output terminal C2 of the B-phase phase-shifting coil, and the output terminal A2 of the C-phase phase-shifting coil are connected to the second circuit L2. By selecting an appropriate gear on a gear shift switch, closed-loop operation of the circuits L1 and L2 can be achieved.

[0045] When the present invention is in operation, the operating phase angles of the first line L1 and the second line L2 are first obtained, and the difference between the two is calculated. According to the requirements of leading or lagging, the shift switches K2a, K2b and K2c are adjusted to make the first line L1 and the second line L2 operate in a closed loop.

[0046] The compact phase-shifting transformer in this invention has a phase-shifting angle range of 0 to 12°, which better matches the actual operating conditions of current power distribution networks. This 0-12° phase-shifting angle range enables the use of delta-connected orthogonal phase shifting, significantly simplifying the phase-shifting transformer structure, reducing its size, and lowering its manufacturing cost.

[0047] Finally, it should be noted that the above embodiments are intended only to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art will appreciate that the technical solutions described in the above embodiments may be modified or some or all of the technical features thereof may be replaced with equivalents, and that such modifications or replacements do not deviate from the essence of the corresponding technical solutions within the scope of the various embodiments of the present invention.

Claims

1. A compact phase-shifting transformer, characterized in that: include: An A-phase iron core leg, an A-phase coil wound on the A-phase iron core leg, a B-phase iron core leg, a B-phase coil wound on the B-phase iron core leg, a C-phase iron core leg, a C-phase coil wound outside the C-phase iron core leg, an A-phase phase-shifting coil wound outside the A-phase coil, a B-phase phase-shifting coil wound outside the B-phase coil, and a C-phase phase-shifting coil wound outside the C-phase coil; The C-phase phase-shifting coil is connected to the same-name end A1 of the A-phase coil via a polarity conversion switch K1a, the A-phase phase-shifting coil is connected to the same-name end B1 of the B-phase coil via a polarity conversion switch K1b, and the B-phase phase-shifting coil is connected to the same-name end C1 of the C-phase coil via a polarity conversion switch K1c; The A-phase phase-shifting coil is provided with a plurality of A-phase taps, which are connected to the shift switch K2a. The output end of the shift switch K2a is the terminal B2 after the B-phase coil is shifted. The B-phase phase-shifting coil is provided with a plurality of B-phase taps, which are connected to the shift switch K2b. The output end of the shift switch K2b is the terminal C2 of the C-phase coil after phase shifting. The C-phase phase-shifting coil is provided with a plurality of C-phase taps, which are connected to the shift switch K2c. The output end of the shift switch K2c is the terminal A2 of the A-phase coil after phase shifting. One end of the A-phase phase-shift coil is a positive terminal, and the other end is a negative terminal, and the polarity conversion switch K1a is connected to the positive terminal or the negative terminal; one end of the B-phase phase-shift coil is a positive terminal, and the other end is a negative terminal, and the polarity conversion switch K1b is connected to the positive terminal or the negative terminal; one end of the C-phase phase-shift coil is a positive terminal, and the other end is a negative terminal, and the polarity conversion switch K1c is connected to the positive terminal or the negative terminal; The like-name end of the A-phase phase-shift coil is connected to the negative pole of the polarity conversion switch K1a, and the opposite-name end of the A-phase phase-shift coil is connected to the positive pole of the polarity conversion switch K1a; the like-name end of the B-phase phase-shift coil is connected to the negative pole of the polarity conversion switch K1b, and the opposite-name end of the B-phase phase-shift coil is connected to the positive pole of the polarity conversion switch K1b; the like-name end of the C-phase phase-shift coil is connected to the negative pole of the polarity conversion switch K1c, and the opposite-name end of the B-phase phase-shift coil is connected to the positive pole of the polarity conversion switch K1c.

2. The compact phase-shifting transformer according to claim 1, characterized in that: The A-phase phase-shifting coil, the B-phase phase-shifting coil, and the C-phase phase-shifting coil are arranged in the same manner.

3. The compact phase-shifting transformer according to claim 1, characterized in that: The A-phase coil, the B-phase coil, and the C-phase coil are connected in a delta shape.

4. The compact phase-shifting transformer according to claim 1, characterized in that: The number of taps on the A-phase phase-shifting coil is a factor of 12.

5. The compact phase-shifting transformer according to claim 4, characterized in that: The number of taps on the A-phase phase-shifting coil is 6.

6. The compact phase-shifting transformer according to claim 5, characterized in that: The polarity conversion switch K1a, the polarity conversion switch K1b, and the polarity conversion switch K1c have the same connection polarity.

7. A transformer working system, characterized in that: The compact phase-shifting transformer comprises the compact phase-shifting transformer according to any one of claims 1 to 6, further comprising a first line L1 and a second line L2; the output terminal A1 of the A-phase coil, the output terminal B1 of the B-phase coil, and the output terminal C1 of the C-phase coil of the compact phase-shifting transformer are connected to the first line L1, and the output terminal of the A-phase phase-shifting coil, the output terminal of the B-phase phase-shifting coil, and the output terminal of the C-phase phase-shifting coil are connected to the second line L2.

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