A structure of a high-voltage plant dry-type transformer

Abstract

This utility model discloses a high-voltage dry-type transformer structure that can effectively reduce the size of the casing and thus the installation footprint. It includes three single-phase transformers arranged side by side. Each single-phase transformer includes a casing, a transformer body inside the casing, a clamp fixed to the top of the transformer body, and a current transformer fixed to the clamp and sleeved on the high-voltage side busbar of the transformer body. The clamp extends along the width of the transformer body. The high-voltage terminal of the transformer body is located on the front side of the transformer body and at the top of the transformer body. The low-voltage terminal of the transformer body is located on the rear side of the transformer body and is electrically connected to the load through a first connecting lead passing through the top of the casing. The current transformer is electrically connected to the high-voltage terminal through a second connecting lead. The high-voltage terminals of two adjacent transformer bodies and the high-voltage terminals of two transformer bodies at both ends are electrically connected through a third connecting lead passing through the side of the casing and located on the front side of the transformer body.

Description

Technical Field

[0001] This utility model relates to the field of transformer technology, and in particular to a structure of a high-voltage dry-type transformer for plant use. Background Technology

[0002] Dry-type transformers used in power plants typically include three types: excitation rectifier dry-type transformers, high-voltage dry-type transformers, and low-voltage dry-type transformers. High-voltage dry-type transformers supply power to high-voltage electrical equipment within the plant; their output sides are high-voltage or medium-voltage, used to supply power to high-voltage or medium-voltage equipment. To meet the requirements of isolated phase busbar interfaces, high-voltage dry-type transformers typically consist of three single-phase transformers forming a three-phase transformer. Currently, existing three-phase transformer structures in the industry place the single-phase transformers longitudinally (e.g.,...). Figure 1-3 As shown in the diagram, three single-phase transformers are arranged side-by-side, with the two high-voltage coils 2 of transformer 1 symmetrically arranged. Terminals 3 are located on the front and back sides of the housing 4. The two high-voltage coils 2 are connected from the side of transformer 1 via copper busbars. This necessitates increasing the dimensions of housing 4 on three sides to accommodate the electrical distances to the high-voltage terminals and leads, thus increasing the size of housing 4 and consequently the installation area of ​​the power distribution room. Furthermore, according to design requirements, when it is necessary to increase the distance between transformers A, B, and C 1 and the phase busbars, the only adjustment can be made by increasing the size of housing 4, further increasing the area occupied during installation in the power distribution room. Utility Model Content

[0003] Therefore, it is necessary to provide a high-voltage plant dry-type transformer structure that can effectively reduce the size of the casing, addressing the aforementioned shortcomings.

[0004] A high-voltage dry-type transformer structure includes three single-phase transformers arranged side by side. Each single-phase transformer includes a casing, a transformer body housed within the casing, a clamp fixed to the top of the transformer body, and a current transformer fixed to the clamp and sleeved on the high-voltage side busbar of the transformer body. The top of the casing has a through hole corresponding to the current transformer. The clamp extends along the width direction of the transformer body. The high-voltage terminal of the transformer body is located on the front side and at the top of the transformer body. The low-voltage terminal of the transformer body is located on the rear side of the transformer body and is electrically connected to the load through a first connecting lead passing through the top of the casing. The current transformer is electrically connected to the high-voltage terminal through a second connecting lead. The high-voltage terminals of two adjacent transformer bodies and the high-voltage terminals of two transformer bodies at both ends are electrically connected through a third connecting lead passing through the side of the casing and located on the front side of the transformer body.

[0005] In one embodiment, the single-phase transformer further includes a first insulator fixed to the front side of the clamp, or two first insulators respectively fixed to the front side and bottom of the clamp, the first insulator having segmented copper busbars fixed on it, and the two ends of the third connecting lead being respectively connected to the segmented copper busbars on the corresponding transformer body.

[0006] In one embodiment, a first insulator fixed to the front side of the clamp or a segmented copper busbar fixed to the first insulator at the bottom of the clamp is connected to a current transformer via a second connecting lead.

[0007] In one embodiment, the single-phase transformer further includes a second insulator fixed to one end of the top of the clamp, the second insulator being electrically connected to the current transformer via a fourth connecting lead.

[0008] In one embodiment, the single-phase transformer further includes a lead clamp fixed to the clamp and pressing against the third connecting lead.

[0009] In one embodiment, the lead clamp is provided with at least one arc-shaped relief opening along its length direction, the inner contour shape of the arc-shaped relief opening being adapted to the outer contour shape of the third connecting lead.

[0010] In one embodiment, the clamp includes a main body with a C-shaped cross-section extending along the width of the transformer body, a support plate fixed at the opening of the main body and extending along the width of the transformer body, and a plurality of mounting holes are provided on the top and bottom surfaces of the main body and the support plate.

[0011] In one embodiment, the transformer body further includes a flange located on the outside of the housing and fixedly connected to the top surface of the housing, the internal space of the flange communicating with a through hole.

[0012] In one embodiment, the bottom of the outer casing has an air hole, and the outer casing contains a fan, a thermostat electrically connected to the fan, and a heating dehumidifier electrically connected to the thermostat.

[0013] In one embodiment, the bottom of the housing is provided with support feet.

[0014] The high-voltage dry-type transformer structure of this utility model places the high-voltage terminals on the front side of the transformer body and the low-voltage terminals on the rear side, achieving a lateral arrangement of the transformer body. Thus, when three single-phase transformers are arranged side-by-side and connected using a delta connection, the high-voltage terminals of each transformer body are located on the same side, all on the front side of the casing. In this case, only the distance on the front of the casing needs to be increased to meet electrical clearance requirements, effectively reducing the size of the casing and consequently reducing the area occupied during installation in the power distribution room. When it is necessary to increase the distance between the three single-phase transformers and the phase busbar, only the position of the current transformer on the clamp needs to be adjusted, without changing the size of the casing, further reducing the size of the casing and the area occupied by the equipment during installation in the power distribution room. Attached Figure Description

[0015] Figure 1 This is a front view of a three-phase transformer with a single-phase transformer placed longitudinally.

[0016] Figure 2 This is a top view of a three-phase transformer with a single-phase transformer placed longitudinally.

[0017] Figure 3 This is a side view of a three-phase transformer with a single-phase transformer placed longitudinally.

[0018] Figure 4 This is a front view of the high-voltage plant dry-type transformer structure in one embodiment of the present invention;

[0019] Figure 5 This is a side view of the structure of a high-voltage dry-type transformer for plant use in one embodiment of the present invention. Detailed Implementation

[0020] To make the above-mentioned objects, features, and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a full understanding of this utility model. However, this utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this utility model. Therefore, this utility model is not limited to the specific embodiments disclosed below.

[0021] Please combine Figure 4 and Figure 5This utility model discloses a high-voltage dry-type transformer structure 10 that can effectively reduce the size of the outer casing. The high-voltage dry-type transformer structure 10 includes three single-phase transformers arranged side by side. Each single-phase transformer includes an outer casing 100, a transformer body 200 housed in the outer casing 100, a clamp 300 fixed to the top of the transformer body 200, and a current transformer 400 fixed to the clamp 300 and sleeved on the high-voltage side busbar (high-voltage incoming line side) of the transformer body 200. The top of the outer casing 100 is provided with a through hole 110 corresponding to the current transformer 400. The clamp 300 extends along the width direction of the transformer body 200, which refers to the left and right sides of the transformer body 200. The high-voltage terminal of the transformer body 200 is located on the front side of the transformer body 200 and at the top of the transformer body 200. The low-voltage terminal 210 of the transformer body 200 is located on the rear side of the transformer body 200 and is electrically connected to the load through the first connecting lead 220 passing through the top of the outer casing 100. The current transformer 400 is electrically connected to the high-voltage terminal 240 through the second connecting lead 230. The high-voltage terminals 240 of two adjacent transformer bodies 200 and the high-voltage terminals 240 of the two transformer bodies 200 at both ends are electrically connected through the third connecting lead 250 passing through the side of the outer casing 100 and located on the front side of the transformer body. That is, the three single-phase transformers adopt a delta connection. In this embodiment, the transformer body 200 is a common single-phase transformer on the market. It mainly includes an iron core, a high-voltage winding connected to the power distribution system, and a low-voltage winding connected to the load. The high-voltage winding ends at high-voltage terminals 240, and the low-voltage winding ends at low-voltage terminals 210. The high-voltage terminals 240 and 210 are respectively connected to the outside of the outer casing 100 through corresponding connecting leads to connect the power supply line and the load line. Its specific structure and working principle are common knowledge in the industry and will not be described in detail here. In this embodiment, the current transformer 400 is sleeved on the high-voltage terminal 240 of the transformer body 200. The purpose is to accurately compare the incoming and outgoing currents to achieve differential protection for the transformer body 200. It can also measure the impedance at the fault point to achieve distance protection for the transformer body 200. In addition, the fault direction can be determined based on the phase signal of the current transformer 400 to achieve directional protection for the transformer body 200.

[0022] The aforementioned high-voltage dry-type transformer structure 10 places the high-voltage terminals 240 of the transformer body 200 on the front side of the transformer body 200 and the low-voltage terminals 210 on the rear side of the transformer body 200, achieving a lateral arrangement of the transformer body 200. Thus, when three single-phase transformers are arranged side-by-side and connected using a delta connection, the high-voltage terminals 240 of each transformer body 200 are located on the same side, all on the front side of the casing 100. In this case, only the distance on the front of the casing 100 needs to be increased to meet the electrical clearance requirements, effectively reducing the size of the casing 100 and consequently reducing the area occupied during installation in the power distribution room. When it is necessary to increase the distance between the three single-phase transformers and the phase busbar, only the position of the current transformer 400 on the clamp 300 needs to be adjusted, without changing the size of the casing 100, further reducing the size of the casing 100 and the area occupied by the equipment during installation in the power distribution room. Furthermore, when each single-phase transformer is arranged horizontally (with the high-voltage terminal 240 located at the front of the transformer body 200 and the low-voltage terminal 210 located at the rear of the transformer body 200), the third connecting lead 250 is always located at the front of the transformer body 200. In this case, the side dimensions of the casing 100 are smaller than the front dimensions, which aligns with the dimensions and orientation of other electrical equipment in the plant. This facilitates the arrangement of other equipment in the power distribution room and reduces the installation area. The high-voltage plant dry-type transformer structure 10 has a simple overall layout, reduces the size of the casing 100, and simultaneously optimizes the layout of the power distribution room, saving costs and installation area, making it highly applicable.

[0023] In one embodiment, each transformer body 200 includes two high-voltage windings (or high-voltage coils), the lower parts of which are electrically connected via a connecting lead 260. The single-phase transformer also includes a first insulator 500 fixed to the front side of the clamp 300, or two first insulators 500 respectively fixed to the front side and bottom of the clamp 300. Segmented copper busbars 600 are fixed to the first insulator 500, and the two ends of the third connecting lead 250 are respectively connected to the segmented copper busbars 600 on the corresponding transformer body 200. Further, the segmented copper busbars 600 fixed to the first insulator 500 on the front side of the clamp 300 or the first insulator 500 fixed to the bottom of the clamp 300 are connected to the current transformer 400 via a second connecting lead 230.

[0024] Specifically, in this embodiment, the three single-phase transformers are designated as single-phase transformer No. 1, single-phase transformer No. 2, and single-phase transformer No. 3, arranged sequentially from left to right. The clamp 300 of single-phase transformer No. 1 has a first insulator 500 on both its front and bottom sides, with the first insulator 500 on the front side of clamp 300 located to the left of the bottom insulator. The clamp 300 of single-phase transformer No. 2 has a first insulator 500 on its front side, and the clamp 300 of single-phase transformer No. 3 has a first insulator 500 on both its front and bottom sides, with the first insulator 500 on the front side of clamp 300 located to the right of the bottom insulator. When the three single-phase transformers are connected, one end of the segmented copper busbar 600 on the front side of the clamp 300 of the No. 1 single-phase transformer is electrically connected to the current transformer 400 through the second connecting lead 230, and the other end of the segmented copper busbar 600 is electrically connected to the first high-voltage winding of the No. 1 single-phase transformer through the connecting wire. The first high-voltage winding and the second high-voltage winding of the No. 1 single-phase transformer, and the first high-voltage winding and the second high-voltage winding of the No. 2 single-phase transformer are electrically connected through the same third connecting lead 250. The bottom end of the segmented copper busbar 600 at the bottom of the clamp 300 of the No. 1 single-phase transformer is electrically connected to the second high-voltage winding of the No. 1 single-phase transformer. The top end of the segmented copper busbar 600 at the bottom of the clamp 300 of the No. 1 single-phase transformer is electrically connected to the top end of the segmented copper busbar 600 at the bottom of the clamp 300 of the No. 3 single-phase transformer via another third connecting lead 250 that passes through the housing 100 of the No. 1 single-phase transformer, the housing 100 of the No. 2 single-phase transformer, and the housing 100 of the No. 3 single-phase transformer. The bottom end of the segmented copper busbar 600 at the bottom of the clamp 300 of the No. 3 single-phase transformer is electrically connected to the first high-voltage winding of the No. 3 single-phase transformer. The top end of the segmented copper busbar 600 is also electrically connected to the current transformer 400 of the No. 3 single-phase transformer via a second connecting lead 230. In single-phase transformer No. 2, the high-voltage winding located below the segmented copper busbar 600 is electrically connected to the bottom end of the segmented copper busbar 600 via a connecting wire. The top end of the segmented copper busbar 600 is electrically connected to the current transformer 400 of single-phase transformer No. 2 via a second connecting lead 230. The middle part of the segmented copper busbar 600 is electrically connected to the top end of the segmented copper busbar 600 in front of the clamp 300 of single-phase transformer No. 3 via another third connecting lead 250. The bottom end of the segmented copper busbar 600 in front of the clamp 300 of single-phase transformer No. 3 is electrically connected to the second high-voltage winding of single-phase transformer No. 3. Thus, the three single-phase transformers are connected via three third connecting leads 250 located in front of the transformer body 200, thereby achieving a delta connection.

[0025] Furthermore, in this embodiment, the single-phase transformer also includes a lead clamp 700 fixed to the clamp 300 and pressing the third connecting lead 250. The lead clamp 700 extends along the height direction of the transformer body 200 and is screwed to the clamp 300 and the transformer body 200. Preferably, the lead clamp 700 has at least one arc-shaped relief opening along its length direction. The inner contour shape of the arc-shaped relief opening is adapted to the outer contour shape of the third connecting lead 250. The number and position of the arc-shaped relief openings on the lead clamp 700 are adapted to the number and position of the third connecting lead 250 clamped by the lead clamp 700. In this way, the joint operation of the lead clamp 700 and the first insulator 500 can achieve the positioning of the third connecting lead, increasing the number of connection points between the third connecting lead and the transformer body 200 and the clamp 300, improving the stability when the three single-phase transformers are interconnected, and avoiding the problem of decreased connection reliability caused by vibration and loosening of the connection between the third connecting lead 250 and the high-voltage terminal 240 due to the large distance between the three single-phase transformers and the phase busbar and the long length of the third connecting lead 250 forming a delta connection. This also eliminates the hidden danger of equipment burnout and reduces safety risks.

[0026] In one embodiment, the single-phase transformer further includes a second insulator 800 fixed at one end of the top of the clamp 300. The second insulator 800 is electrically connected to the current transformer 400 via a fourth connecting lead 810. The fourth connecting lead 810 is a secondary equipotential signal line used to eliminate ground loop interference of the current transformer 400 to ensure measurement accuracy and prevent the accumulation of induced voltage to establish a safe grounding path. It can also transmit secondary side signals to instruments or protection devices as needed.

[0027] The clamp 300 includes a main body 310 with a C-shaped cross-section extending along the width of the transformer body 200, and a support plate 320 fixed at the opening of the main body 310 and extending along the width of the transformer body 200. Several mounting holes 330 are provided on the top and bottom surfaces of the main body 310 and the support plate 320. This allows the current transformer 400 to be installed by adjusting its position on the top surface of the main body 310 to accommodate the distance between the three-phase transformer and the phase busbar (i.e.,...). Figure 4 The installation height of the lead clamp 700 on the support plate 320 is adjusted according to the length of the lead clamp 700, and the position of the first insulator 500 in the length direction of the support plate 320 is adjusted according to the position of the high voltage winding of the transformer body 200. In this embodiment, the entire clamp 300 is actually a hollow structure, which helps to reduce the weight of the entire single-phase transformer; the support plate 320 is welded to the inner side of the main body 310 to improve the connection strength between the two.

[0028] In addition, in this embodiment, the transformer body also includes a flange 900 located outside the outer casing 100 and fixedly connected to the top surface of the outer casing 100. The internal space of the flange 900 communicates with the through hole 110. When three single-phase transformers are connected to form a three-phase transformer, the high-voltage terminals 240 of the transformer bodies of the three single-phase transformers are connected in a delta configuration, and the low-voltage terminals 210 of the transformer bodies of the three single-phase transformers are each connected to a first connecting lead 220. The three connecting leads are bundled together and led out to serve as the neutral line. In other words, the high-voltage dry-type transformer structure 10 of this embodiment adopts a Δ-Y connection group (Dyn11 connection). By setting the flange 900, it is convenient to install the current transformer 400 into the outer casing 100, providing an interface for debugging and verification of the current transformer 400, and facilitating observation and troubleshooting of the current transformer 400. In actual use, an openable cover can also be set at the flange 900.

[0029] In one embodiment, the bottom of the outer casing 100 has an air vent. Inside the outer casing 100 are a fan, a thermostat electrically connected to the fan, and a dehumidifier electrically connected to the thermostat. The thermostat includes a display panel on the outer surface of the outer casing 100, a temperature sensor located inside the outer casing 100, and a control unit electrically connected to the temperature sensor. The fan is electrically connected to the control unit. Thus, when the thermostat detects that the temperature inside the outer casing 100 is higher than a preset value, the fan receives an electrical signal from the control unit and operates to agitate the air inside the outer casing 100, causing hot air to escape from the through-hole 110 at the top of the outer casing 100, thereby cooling the air inside the outer casing 100 at various times. The dehumidifier is installed on the inner side wall or bottom of the outer casing 100 and includes a temperature and humidity sensor electrically connected to the control unit and an electric heating plate or heating rod electrically connected to the control unit. Thus, when the single-phase transformer is out of service or the ambient humidity is high, the electric heating plate or heating rod automatically starts and heats the air inside the outer casing 100, preventing condensation and protecting the internal insulation and metal components of the outer casing 100 from moisture corrosion.

[0030] Furthermore, in this embodiment, the bottom of the housing 100 is provided with a support foot 120. By providing the support foot 120 at the bottom of the housing 100, the height of the bottom of the housing 100 can be raised to prevent rainwater and other external water from entering the inner cavity of the housing 100 through the air vents at the bottom of the housing 100, thereby preventing leakage accidents caused by water immersion of electrical components.

[0031] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0032] The embodiments described above are merely illustrative of several implementations of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

Claims

1. A structure for a high-voltage plant service dry-type transformer, characterized in that, The system includes three single-phase transformers arranged side by side. Each single-phase transformer includes a casing, a transformer body housed within the casing, a clamp fixed to the top of the transformer body, and a current transformer fixed to the clamp and connected to the high-voltage busbar of the transformer body. The top of the casing has a through hole corresponding to the current transformer. The clamp extends along the width of the transformer body. The high-voltage terminal of the transformer body is located on the front side and at the top of the transformer body. The low-voltage terminal of the transformer body is located on the rear side of the transformer body and is connected to the load through a first connecting lead passing through the top of the casing. The current transformer is electrically connected to the high-voltage terminal through a second connecting lead. The high-voltage terminals of two adjacent transformer bodies and the two high-voltage terminals of the two transformer bodies at both ends are electrically connected through a third connecting lead passing through the side of the casing and located on the front side of the transformer body.

2. The structure of the high-voltage dry-type transformer for plant use according to claim 1, characterized in that, The single-phase transformer also includes a first insulator fixed on the front side of the clamp, or two first insulators respectively fixed on the front side and bottom of the clamp. The first insulator is fixed with segmented copper busbars, and the two ends of the third connecting lead are respectively connected to the segmented copper busbars on the corresponding transformer body.

3. The structure of the high-voltage dry-type transformer for plant use according to claim 2, characterized in that, The first insulator fixed to the front side of the clamp or the segmented copper busbar fixed to the first insulator at the bottom of the clamp is connected to the current transformer via the second connecting lead.

4. The structure of the high-voltage dry-type transformer for plant use according to claim 1, characterized in that, The single-phase transformer also includes a second insulator fixed at one end of the top of the clamp, and the second insulator is electrically connected to the current transformer through a fourth connecting lead.

5. The structure of the high-voltage dry-type transformer for plant use according to claim 1, characterized in that, The single-phase transformer also includes a lead clamp fixed on the clamp and pressing the third connecting lead.

6. The structure of the high-voltage dry-type transformer for plant use according to claim 5, characterized in that, The lead clamp has at least one arc-shaped relief opening along its length direction, and the inner contour shape of the arc-shaped relief opening is adapted to the outer contour shape of the third connecting lead.

7. The structure of the high-voltage dry-type transformer for plant use according to claim 1, characterized in that, The clamp includes a main body with a C-shaped cross-section extending along the width of the transformer body, and a support plate fixed at the opening of the main body and extending along the width of the transformer body. Several mounting holes are provided on the top and bottom surfaces of the main body and on the support plate.

8. The structure of the high-voltage plant service dry-type transformer according to claim 1, characterized in that, The transformer body also includes a flange located on the outside of the casing and fixedly connected to the top surface of the casing, the internal space of the flange communicating with a through hole.

9. The structure of the high-voltage dry-type transformer for plant use according to claim 1, characterized in that, The bottom of the outer casing has an air hole, and inside the outer casing is a fan, a thermostat electrically connected to the fan, and a heating dehumidifier electrically connected to the thermostat.

10. The structure of the high-voltage dry-type transformer for plant use according to claim 1, characterized in that, The bottom of the casing is provided with support feet.

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