A transformer for high current low impedance short circuit test
By introducing air gaps and epoxy laminates into the transformer core structure, combined with improvements to the coils and support frame, the problems of core saturation and voltage output during short-circuit tests were solved, achieving stability and providing support under multiple voltage conditions.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SUNTEN ELECTRICAL EQUIP CO LTD
- Filing Date
- 2025-07-16
- Publication Date
- 2026-07-14
AI Technical Summary
In existing electrical equipment testing, transformers are prone to core magnetic saturation when simulating short-circuit faults, and it is difficult to provide the test requirements of various voltage conditions and frequent short-circuit operation.
Design a transformer for high current, low impedance short-circuit testing. The transformer uses an open air gap in the core structure, filled with epoxy laminate to increase magnetic reluctance and prevent core saturation. The coil structure outputs different voltages through series or parallel connection. The support frame is equipped with an internal reinforcing mechanism to fix the core and withstand short-circuit forces.
It enables the core to operate in the unsaturated region, meets the no-load-short-circuit cycle condition, provides multiple voltage conditions, and enhances the stability and short-circuit resistance of the transformer.
Smart Images
Figure CN224501629U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the technical field of transformers, and in particular to a transformer for high current, low impedance short-circuit testing. Background Technology
[0002] Electrical equipment testing centers conduct various operating condition tests on electrical equipment such as transformers, circuit breakers, and switchgear. During the testing process, large currents are applied to the electrical equipment to simulate the extreme high current conditions that occur when a short-circuit fault occurs. Therefore, this application proposes a low-impedance short-circuit test transformer for use in electrical equipment testing centers. This low-impedance short-circuit test transformer can provide multi-voltage output and frequent short-circuit operation test conditions for the testing of the aforementioned electrical equipment. Utility Model Content
[0003] To overcome the above-mentioned technical defects, this utility model provides a transformer for high-current, low-impedance short-circuit testing, which can perform various operating condition tests on electrical equipment such as transformers, circuit breakers, and switchgear.
[0004] This utility model is implemented according to the following technical solution:
[0005] This application provides a transformer for high-current, low-impedance short-circuit testing, comprising:
[0006] The core structure includes a core column and a yoke. The core column includes an upper core column and a lower core column. The upper core column and the lower core column are disconnected to form an air gap space. The air gap space is filled with an epoxy laminate.
[0007] A coil structure is sleeved on the iron core column; the coil structure includes a high-voltage winding and a low-voltage winding, and the high-voltage winding and the low-voltage winding are connected in series or in parallel to achieve different output voltages;
[0008] The support frame includes an outer frame and an inner reinforcing mechanism. The outer frame is disposed outside the core structure, and one end of the inner reinforcing mechanism is connected to the core structure, while the other end is connected to the outer frame.
[0009] Compared with the prior art, the core structure of this application can prevent core magnetic saturation, increase the magnetic resistance in the core circuit, and keep the core in the unsaturated region during the test, thus meeting the operating conditions under no-load-short-circuit cycle. Moreover, the coil structure can output different voltages to provide different voltage conditions for the electrical equipment under test. In addition, the support frame has an added internal reinforcing mechanism, which can effectively fix the core structure while bearing the short-circuit force during the short-circuit test.
[0010] In one embodiment, the upper core column is provided with a first mounting hole, and the lower core column is provided with a second mounting hole. The first mounting hole and the second mounting hole are symmetrically distributed along the air gap space.
[0011] The core structure also includes a pull plate, which is connected to the first mounting hole via a first insulating locking member and to the second mounting hole via a second insulating locking member.
[0012] In one embodiment, the first insulating locking member and the second insulating locking member have the same structure;
[0013] The first insulating locking component includes a clamping screw, a threaded bushing, and an insulating bushing. The clamping screw is inserted into the first mounting hole and is covered with an epoxy tube. Both ends of the clamping screw are threadedly connected to the threaded bushing, and the insulating bushing is provided on the side of the threaded bushing near the core column.
[0014] In one embodiment, the outer frame includes two parallel upper crossbeams, two parallel base supports, two parallel longitudinal supports, two parallel diagonal supports, and multiple connecting beams; wherein the two upper crossbeams, the two base supports, and the two longitudinal supports are all connected by the connecting beams.
[0015] The lower ends of the two longitudinal supports are respectively connected to the rear ends of the two base supports, and the upper ends of the two longitudinal supports are respectively connected to the rear ends of the two upper crossbeams.
[0016] The lower ends of the two longitudinal supports are respectively connected to the rear ends of the two base supports, and the upper ends of the two longitudinal supports are respectively connected to the rear ends of the two upper crossbeams.
[0017] In one embodiment, the inner reinforcing mechanism includes an upper reinforcing beam, a lower reinforcing beam, and a middle reinforcing beam. The upper end of the middle reinforcing beam is connected to the upper reinforcing beam, and the lower end of the middle reinforcing beam is connected to the lower reinforcing beam, so that the inner reinforcing mechanism is in the shape of an "I".
[0018] The front end of the upper reinforcing beam is connected to the core clamp located at the upper end of the core structure, and the rear end of the upper reinforcing beam is connected to the longitudinal support; the front end of the lower reinforcing beam is connected to the core clamp located at the lower end of the core structure, and the rear end of the lower reinforcing beam is connected to the longitudinal support.
[0019] In one embodiment, the high-voltage winding includes a first sub-winding, a second sub-winding, a third sub-winding, a fourth sub-winding, a fifth sub-winding, and a sixth sub-winding; the first sub-winding, the second sub-winding, and the third sub-winding are defined as the upper half of the winding, and the fourth sub-winding, the fifth sub-winding, and the sixth sub-winding are defined as the lower half of the winding.
[0020] The taps on the first, second, third, fourth, fifth, and sixth sub-windings are connected in different series or parallel combinations to form at least four different voltage levels of output.
[0021] In one embodiment, the voltage of the first sub-winding is 1.25kV, the voltage of the second sub-winding is 1.25kV, the voltage of the third sub-winding is 3.75kV, the voltage of the fourth sub-winding is 3.75kV, the voltage of the fifth sub-winding is 1.25kV, and the voltage of the sixth sub-winding is 1.25kV; wherein,
[0022] The first, second, and third sub-windings are connected in series, and the fourth, fifth, and sixth sub-windings are connected in series. The upper half of the windings is connected in series with the lower half of the windings, outputting a 12.5kV voltage.
[0023] The first sub-winding is connected in parallel with the second sub-winding and then connected in series with the third sub-winding. The fifth sub-winding is connected in parallel with the sixth sub-winding and then connected in series with the fourth sub-winding. The upper half of the winding is connected in series with the lower half of the winding to output a 10kV voltage.
[0024] The first, second, and third sub-windings are connected in series, and the fourth, fifth, and sixth sub-windings are connected in series. The upper half of the windings is connected in parallel with the lower half of the windings, outputting a voltage of 6.25kV.
[0025] The first sub-winding is connected in parallel with the second sub-winding and then in series with the third sub-winding. The fifth sub-winding is connected in parallel with the sixth sub-winding and then in series with the fourth sub-winding. The upper half of the winding is connected in parallel with the lower half of the winding, and the output voltage is 5kV.
[0026] In one embodiment, the transformer for high-current, low-impedance short-circuit testing further includes a copper busbar structure, which is connected in series or in parallel with the coil structure to achieve different output voltages.
[0027] In one embodiment, the copper busbar structure includes a first copper busbar, a second copper busbar, and an output copper busbar;
[0028] The low-voltage winding includes an upper low-voltage winding and a lower low-voltage winding, the upper low-voltage winding and the lower low-voltage winding are connected in series; the upper low-voltage winding is connected to the first copper busbar, and the lower low-voltage winding is connected to the second copper busbar.
[0029] One end of the output copper busbar is connected to the first copper busbar, and the other end of the output copper busbar is provided with a user terminal.
[0030] In one embodiment, the copper busbar structure includes a first copper busbar, a second copper busbar, and an output copper busbar;
[0031] The low-voltage winding includes an upper low-voltage winding and a lower low-voltage winding, wherein the upper low-voltage winding and the lower low-voltage winding are connected in parallel; the upper low-voltage winding is connected to the first copper busbar, and the lower low-voltage winding is connected to the second copper busbar.
[0032] One end of the output copper busbar is connected to both the first copper busbar and the second copper busbar, and the other end of the output copper busbar is provided with a user terminal. Attached Figure Description
[0033] The specific embodiments of this utility model will be further described in detail below with reference to the accompanying drawings, wherein:
[0034] Figure 1 This is a front view of the transformer used for high-current, low-impedance short-circuit testing according to this utility model.
[0035] Figure 2 This is a side view of the transformer used for high-current, low-impedance short-circuit testing according to this utility model.
[0036] Figure 3 This is a schematic diagram of the iron core column of this utility model;
[0037] Figure 4 This is a cross-sectional view of the iron core column of this utility model;
[0038] Figure 5 This is one of the schematic diagrams of the winding connection of this utility model;
[0039] Figure 6 This is the second schematic diagram of the winding connection of this utility model;
[0040] Figure 7 This is the third schematic diagram of the winding connection of this utility model;
[0041] Figure 8 This is the fourth schematic diagram of the winding connection of this utility model;
[0042] Figure 9 This is one of the side views showing the connection between the low-voltage winding and the copper busbar structure of this utility model;
[0043] Figure 10 This is one of the main views showing the connection between the low-voltage winding and the copper busbar structure of this utility model;
[0044] Figure 11 This is a second side view of the connection between the low-voltage winding and the copper busbar structure of this utility model.
[0045] Figure 12 This is the second main view of the connection between the low-voltage winding and the copper busbar structure of this utility model.
[0046] Explanation of reference numerals in the attached figures:
[0047] 10 Core structure, 110 Core column, 111 Upper core column, 1111 First mounting hole, 112 Lower core column, 1121 Second mounting hole, 113 Air gap space, 114 Epoxy laminate, 115 Pull plate, 1161 Clamping screw, 1162 Threaded bushing, 1163 Insulating bushing, 120 Yoke, 20 Coil structure, 211 First sub-winding, 212 Second sub-winding, 213 Third sub-winding, 214 Fourth sub-winding, 215 Fifth sub-winding, 216 Sixth sub-winding, 221 Low-voltage upper winding, 222 Low-voltage lower winding, 30 Support frame, 310 Upper crossbeam, 320 Base bracket, 330 Longitudinal bracket, 340 Diagonal bracket, 350 Connecting beam, 360 Upper reinforcing beam, 370 Lower reinforcing beam, 380 Middle reinforcing beam. Detailed Implementation
[0048] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.
[0049] To better illustrate this utility model, a further detailed description of this utility model is provided below with reference to the accompanying drawings.
[0050] It should be understood that the described embodiments are merely some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of the embodiments of this application.
[0051] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to limit the embodiments of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.
[0052] In the following description, when referring to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims. In the description of this application, it should be understood that the terms "first," "second," "third," etc., are used only to distinguish similar objects and are not necessarily used to describe a specific order or sequence, nor should they be construed as indicating or implying relative importance. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.
[0053] Furthermore, in the description of this application, unless otherwise stated, "multiple" means two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.
[0054] Combination Figures 1 to 12 As shown, this application provides a transformer for high-current, low-impedance short-circuit testing, comprising: a core structure 10, including a core column 110 and a yoke 120, wherein the core column 110 includes an upper core column 111 and a lower core column 112, the upper core column 111 and the lower core column 112 are disconnected to form an air gap space 113, the air gap space 113 is filled with an epoxy laminate 114; a coil structure 20, which is sleeved on the core column 110; the coil structure 20 includes a high-voltage winding and a low-voltage winding, the high-voltage winding and the low-voltage winding are connected in series or in parallel to achieve different output voltages; and a support frame 30, including an outer frame and an inner reinforcing mechanism, the outer frame being disposed outside the core structure 10, one end of the inner reinforcing mechanism being connected to the core structure 10, and the other end being connected to the outer frame.
[0055] Specifically, the high-current, low-impedance short-circuit test transformer of this application is mainly used in various electrical equipment testing centers to apply large currents to electrical equipment such as transformers, circuit breakers, and switchgear, simulating the extreme high-current conditions that occur when a product experiences a short-circuit fault. The operating conditions of the high-current, low-impedance short-circuit test transformer of this application (hereinafter referred to as the transformer of this application) are determined according to the testing requirements of the test object. Multi-voltage output and frequent short-circuit operation are the normal operating conditions of the transformer of this application, and targeted countermeasures need to be taken during the design process based on this operating characteristic. Furthermore, the transformer of this application is a three-phase transformer.
[0056] The frequent short-circuit operation specifically includes the following three typical operating modes: Mode 1: 50kA / 4S energization → 3min power outage → 50kA / 4S energization → 3min power outage, then enter the next cycle; Mode 2: 50kA / 1S energization → 3min power outage → 50kA / 1S energization → 3min power outage, then enter the next cycle; Mode 3: 63kA / 1S energization → 3min power outage → 63kA / 1S energization → 3min power outage, then enter the next cycle. In other words, the transformer in this application needs to continuously cycle under open-circuit and short-circuit conditions, and the core also continuously switches between no-load and short-circuit states, resulting in continuous changes in the magnetic field. Due to the residual magnetism of the core, the core easily reaches the saturation region.
[0057] To address the aforementioned operating conditions, the maximum saturation magnetic flux density of the transformer core in this application is calculated based on 2.0T. To ensure the core remains in the unsaturated region throughout the test, the rated magnetic flux density of the transformer in this application needs to be controlled below 1.1T. However, the lower magnetic flux density leads to an increase in the core cross-section. In design and manufacturing, the cross-section of the transformer core in this application is 45% larger than that of conventional products (conventional transformers) of the same capacity.
[0058] Meanwhile, to ensure that the short-circuit current output by the transformer of this application is sufficiently large, the short-circuit impedance must be limited to less than 2%. Since the transformer impedance is inversely proportional to the core window height, that is, the higher the core window, the lower the impedance. Therefore, the core height of the transformer of this application is higher than that of conventional products of the same capacity. In other words, the transformer of this application is taller and has a larger cross-section than conventional products of the same capacity, which necessitates a change in the support frame 30 of the transformer of this application. The support frame 30 of the transformer of this application includes an outer frame and an inner reinforcing mechanism. The outer frame is disposed outside the core structure 10, and one end of the inner reinforcing mechanism is connected to the core structure 10, and the other end is connected to the outer frame. The inner reinforcing mechanism can effectively fix the core structure 10 while withstanding the short-circuit force during the short-circuit test.
[0059] Regarding the structure of the outer frame, in this embodiment, the outer frame includes two parallel upper crossbeams 310, two parallel base supports 320, two parallel longitudinal supports 330, two parallel diagonal supports 340, and multiple connecting beams 350; wherein, the two upper crossbeams 310, the two base supports 320, and the two longitudinal supports 330 are all connected by the connecting beams 350; the lower ends of the two longitudinal supports 330 are respectively connected to the rear ends of the two base supports 320, and the upper ends of the two longitudinal supports 330 are respectively connected to the rear ends of the two upper crossbeams 310; the lower ends of the two longitudinal supports 330 are respectively connected to the rear ends of the two base supports 320, and the upper ends of the two longitudinal supports 330 are respectively connected to the rear ends of the two upper crossbeams 310.
[0060] The outer frame manufactured in this embodiment, as described above, has a trapezoidal shape that is narrower at the top and wider at the bottom, as seen in the side view. This provides a wider bottom support surface, lowers the center of gravity of the entire outer frame, and improves overall stability and anti-overturning ability. Moreover, this structure can more effectively resist forces from all directions (especially the horizontal direction), such as seismic forces, wind forces, accidental collisions during equipment operation, or vibrations and electromagnetic forces generated by the transformer itself, greatly reducing the risk of transformer overturning.
[0061] Furthermore, the included angle between the inclined support 340 and the base support 320 is 60° to 80°.
[0062] It should be noted that the upper crossbeam 310, base bracket 320, longitudinal bracket 330, diagonal bracket 340 and connecting beam 350 can all use channel steel, and bolts are used as connecting parts between the channel steel.
[0063] Regarding the structure of the internal reinforcement mechanism, in this embodiment, the internal reinforcement mechanism includes an upper reinforcement beam 360, a lower reinforcement beam 370, and a middle reinforcement beam 380. The upper end of the middle reinforcement beam 380 is connected to the upper reinforcement beam 360, and the lower end of the middle reinforcement beam 380 is connected to the lower reinforcement beam 370, so that the internal reinforcement mechanism is in the shape of an "I". The front end of the upper reinforcement beam 360 is connected to the core clamp located at the upper end of the core structure 10, and the rear end of the upper reinforcement beam 360 is connected to the longitudinal support 330. The front end of the lower reinforcement beam 370 is connected to the core clamp located at the lower end of the core structure 10, and the rear end of the lower reinforcement beam 370 is connected to the longitudinal support 330. The internal reinforcement mechanism can more evenly distribute the vertical load applied by the transformer onto a larger foundation area. This reduces the local pressure on the mounting foundation, which is particularly important for the variable height and width transformer of this application, and can prevent foundation damage.
[0064] It should be noted that, since the transformers in this application are typically placed inside mobile power system containers, the height of the transformers in this application is usually limited by the height of the container space.
[0065] Furthermore, to prevent core magnetic saturation and increase the magnetic reluctance in the core circuit, this embodiment disconnects the core column 110 to form an air gap space 113. Specifically, the core structure 10 includes a core column 110 and a yoke 120. The core column 110 includes an upper core column 111 and a lower core column 112. The upper core column 111 and the lower core column 112 are disconnected to form an air gap space 113, which is filled with an epoxy laminate 114. Preferably, the height of the air gap space 113 is 1–3 mm, and the air gap space 113 is located at 2 / 3 of the height of the core column 110. The epoxy laminate 114 is made of EPGC203 material. The core structure 10 of this application adopts the above structure, which can prevent core magnetic saturation, increase the magnetic reluctance in the core circuit, and keep the core in the unsaturated region during the test, thus meeting the operating conditions under no-load-short-circuit cycle.
[0066] In this embodiment, the upper core column 111 is provided with a first mounting hole 1111, and the lower core column 112 is provided with a second mounting hole 1121. The first mounting hole 1111 and the second mounting hole 1121 are symmetrically distributed along the upper and lower sides of the air gap space 113. The core structure 10 also includes a pull plate 115. The pull plate 115 is connected to the first mounting hole 1111 through a first insulating locking member, and the pull plate 115 is connected to the second mounting hole 1121 through a second insulating locking member to prevent the pull plate 115 from forming a circulation.
[0067] Furthermore, the first insulating locking member and the second insulating locking member have the same structure; the first insulating locking member includes a clamping screw 1161, a threaded bushing 1162 and an insulating bushing 1163, the clamping screw 1161 is inserted into the first mounting hole 1111 and the clamping screw 1161 is covered with an epoxy tube, the two ends of the clamping screw 1161 are respectively threaded to the threaded bushing 1162, and the insulating bushing 1163 is provided on the side of the threaded bushing 1162 near the core column 110.
[0068] In one embodiment, the high-voltage winding includes a first sub-winding 211, a second sub-winding 212, a third sub-winding 213, a fourth sub-winding 214, a fifth sub-winding 215, and a sixth sub-winding 216; the first sub-winding 211, the second sub-winding 212, and the third sub-winding 213 are defined as the upper half of the winding, and the fourth sub-winding 214, the fifth sub-winding 215, and the sixth sub-winding 216 are defined as the lower half of the winding.
[0069] The taps on the first sub-winding 211, the second sub-winding 212, the third sub-winding 213, the fourth sub-winding 214, the fifth sub-winding 215 and the sixth sub-winding 216 are connected in different series or parallel combinations to form at least four different voltage levels of output.
[0070] The high-voltage winding is provided with a first tap I, a second tap II, a third tap III, a fourth tap IV, a fifth tap V, a sixth tap VI, a seventh tap VII, an eighth tap VIII, a ninth tap IX, and a tenth tap X; a first sub-winding 211 is provided between the first tap I and the second tap II; a second sub-winding 212 is provided between the third tap III and the fourth tap IV; a third sub-winding 213 is provided between the fourth tap IV and the fifth tap V; a fourth sub-winding 214 is provided between the sixth tap VI and the seventh tap VII; a fifth sub-winding 215 is provided between the seventh tap VII and the eighth tap VIII; and a sixth sub-winding 216 is provided between the ninth tap IX and the tenth tap X.
[0071] Further, the voltage of the first sub-winding 211 is 1.25kV, the voltage of the second sub-winding 212 is 1.25kV, the voltage of the third sub-winding 213 is 3.75kV, the voltage of the fourth sub-winding 214 is 3.75kV, the voltage of the fifth sub-winding 215 is 1.25kV, and the voltage of the sixth sub-winding 216 is 1.25kV; wherein,
[0072] like Figure 5 As shown, the first sub-winding 211, the second sub-winding 212 and the third sub-winding 213 are connected in series, the fourth sub-winding 214, the fifth sub-winding 215 and the sixth sub-winding 216 are connected in series, and the upper half of the winding is connected in series with the lower half of the winding to output a voltage of 12.5kV.
[0073] That is, the second tap II is connected to the third tap III, the fifth tap V is connected to the sixth tap VI, the eighth tap VIII is connected to the ninth tap IX, the second sub-winding is connected to the third sub-winding, the fourth sub-winding is connected to the fifth sub-winding, the first tap I of phase A is connected to the tenth tap X of phase C, the tenth tap X of phase A is connected to the first tap I of phase B, and the tenth tap X of phase B is connected to the first tap I of phase C, outputting a 12.5kV voltage.
[0074] like Figure 6 As shown, the first sub-winding 211 and the second sub-winding 212 are connected in parallel and then connected in series with the third sub-winding 213. The fifth sub-winding 215 and the sixth sub-winding 216 are connected in parallel and then connected in series with the fourth sub-winding 214. The upper half of the winding is connected in series with the lower half of the winding, and the output voltage is 10kV.
[0075] That is, the first tap I is connected to the third tap III, the second tap II is connected to the fourth tap IV, the fifth tap V is connected to the sixth tap VI, the seventh tap VII is connected to the ninth tap IX, the eighth tap VIII is connected to the tenth tap X, the second sub-winding is connected to the third sub-winding, the fourth sub-winding is connected to the fifth sub-winding, the first tap I of phase A is connected to the tenth tap X of phase C, the tenth tap X of phase A is connected to the first tap I of phase B, and the tenth tap X of phase B is connected to the first tap I of phase C, outputting a 10kV voltage.
[0076] like Figure 7 As shown, the first sub-winding 211, the second sub-winding 212 and the third sub-winding 213 are connected in series, the fourth sub-winding 214, the fifth sub-winding 215 and the sixth sub-winding 216 are connected in series, and the upper half of the winding is connected in parallel with the lower half of the winding to output a voltage of 6.25kV.
[0077] That is, the first tap I is connected to the sixth tap VI, the second tap II is connected to the third tap III, the fifth tap V is connected to the tenth tap X, the eighth tap VIII is connected to the ninth tap IX, the second sub-winding is connected to the third sub-winding, the fourth sub-winding is connected to the fifth sub-winding, the first tap I of phase A is connected to the tenth tap X of phase C, the tenth tap X of phase A is connected to the first tap I of phase B, and the tenth tap X of phase B is connected to the first tap I of phase C, outputting a voltage of 6.25kV.
[0078] like Figure 8 As shown, the first sub-winding 211 and the second sub-winding 212 are connected in parallel and then connected in series with the third sub-winding 213. The fifth sub-winding 215 and the sixth sub-winding 216 are connected in parallel and then connected in series with the fourth sub-winding 214. The upper half of the winding is connected in parallel with the lower half of the winding, and the output voltage is 5kV.
[0079] That is, the first tap I is connected to the sixth tap VI, the first tap I is connected to the third tap III, the second tap II is connected to the fourth tap IV, the fifth tap V is connected to the tenth tap, the fifth tap V is connected to the sixth tap VI, the seventh tap VII is connected to the ninth tap IX, the eighth tap VIII is connected to the tenth tap, the second sub-winding is connected to the third sub-winding, the fourth sub-winding is connected to the fifth sub-winding, the first tap I of phase A is connected to the tenth tap of phase C, the tenth tap of phase A is connected to the first tap I of phase B, and the tenth tap of phase B is connected to the first tap I of phase C, outputting a 5kV voltage.
[0080] In one embodiment, the transformer for high-current low-impedance short-circuit testing further includes a copper busbar structure, which is connected in series or in parallel with the coil structure 20 to achieve different output voltages.
[0081] like Figure 9 and Figure 10 As shown, in one embodiment, the copper busbar structure includes a first copper busbar 13, a second copper busbar 14, and an output copper busbar 21; the low-voltage winding includes a low-voltage upper winding and a low-voltage lower winding, the low-voltage upper winding and the low-voltage lower winding are connected in series; the low-voltage upper winding is connected to the first copper busbar, and the low-voltage lower winding is connected to the second copper busbar; one end of the output copper busbar is connected to the first copper busbar, and the other end of the output copper busbar is provided with a user terminal.
[0082] Specifically, the starting ends of the low-voltage upper windings of phase A, phase B, and phase C coils are led to the middle of their corresponding coils via upper connecting copper busbars 1, 2, 3, 4, 5, and 6. The ending ends of the low-voltage lower windings of phase A, phase B, and phase C coils are led to the middle of their corresponding coils via lower connecting copper busbars 7, 8, 9, 10, 11, and 12. The first copper busbar 13 is connected to the upper connecting copper busbar 1, upper connecting copper busbar 3, and upper connecting copper busbar 5; the upper connecting copper busbar 2, upper connecting copper busbar 4, and upper connecting copper busbar 6 are connected to the lower connecting copper busbar 7, lower connecting copper busbar 9, and lower connecting copper busbar 11 respectively through Z-type copper busbar 15, Z-type copper busbar 16, and Z-type copper busbar 17, so as to realize the connection between the tail end of the low-voltage upper winding of the A-phase, B-phase, and C-phase coil and the head end of the low-voltage lower winding. The lower connecting copper busbar 8 is connected to the second copper busbar 14 via a U-shaped copper busbar 18, and the lower connecting copper busbar 10 is connected to the second copper busbar 14 via a U-shaped copper busbar 19, thus achieving a short circuit at the tail end of the series connection between the low-voltage upper winding and the low-voltage lower winding; the lower connecting copper busbar 12 is connected to the second copper busbar 14 via a U-shaped copper busbar 20, thus achieving the neutral wire lead-out; one end of the output copper busbar 21 is connected to the first copper busbar 13, and the other end of the output copper busbar is provided with a user terminal for connection with electrical equipment, outputting 420V voltage.
[0083] like Figure 11 and Figure 12 As shown, in one embodiment, the copper busbar structure includes a first copper busbar 13, a second copper busbar 14, and an output copper busbar 21; the low-voltage winding includes a low-voltage upper winding and a low-voltage lower winding, the low-voltage upper winding and the low-voltage lower winding being connected in parallel; the low-voltage upper winding is connected to the first copper busbar, and the low-voltage lower winding is connected to the second copper busbar; one end of the output copper busbar is connected to both the first copper busbar and the second copper busbar, and the other end of the output copper busbar is provided with a user terminal.
[0084] Specifically, the starting ends of the low-voltage upper windings of phase A, phase B, and phase C coils are led to the middle of their corresponding coils via upper connecting copper busbars 1, 2, 3, 4, 5, and 6. The ending ends of the low-voltage lower windings of phase A, phase B, and phase C coils are led to the middle of their corresponding coils via lower connecting copper busbars 7, 8, 9, 10, 11, and 12. A direct connecting copper busbar 15' connects the upper connecting copper busbar 1 to... The lower connecting copper busbar 7 is connected, the direct connecting copper busbar 16' connects the upper connecting copper busbar 3 and the lower connecting copper busbar 9, and the direct connecting copper busbar 17' connects the upper connecting copper busbar 5 and the lower connecting copper busbar 11, realizing the parallel connection of the beginning ends of the low-voltage upper winding and the low-voltage lower winding of the A-phase, B-phase and C-phase coils; the vertical sides of the U-shaped copper busbars 18, 19 and 20 are extended and simultaneously overlap with the first copper busbar 13 and the second copper busbar 14, realizing the parallel connection of the end ends of the low-voltage upper winding and the low-voltage lower winding, forming an yn connection. One end of the output copper busbar 21 is simultaneously overlapped with the first copper busbar 13 and the second copper busbar 14, and the other end is overlapped with the user, outputting 210V voltage.
[0085] Furthermore, by changing the connection position of the taps and a small number of low-voltage copper busbars, different combinations of high and low voltage output voltages can be achieved. For example, there can be combinations of low voltage 420V and high voltage 12.5kV, low voltage 420V and high voltage 10kV, low voltage 420V and high voltage 6.25kV, low voltage 420V and high voltage 5kV; as well as combinations of low voltage 210V and high voltage 12.5kV, low voltage 210V and high voltage 10kV, low voltage 210V and high voltage 6.25kV, and low voltage 210V and high voltage 5kV.
[0086] Compared with the prior art, the core structure 10 of this application can prevent core magnetic saturation, increase the magnetic resistance in the core circuit, and keep the core in the unsaturated region during the test, so as to meet the working conditions under the no-load-short-circuit cycle. Moreover, the coil structure 20 can output different voltages to provide different voltage conditions for the electrical equipment under test. In addition, the support frame 30 has an added internal reinforcing mechanism, which can effectively fix the core structure 10 while bearing the short-circuit force during the short-circuit test.
[0087] Based on the disclosure and teachings of the above specification, those skilled in the art can make changes and modifications to the above embodiments. Therefore, this utility model is not limited to the specific embodiments disclosed and described above, and some modifications and changes to this utility model should also fall within the protection scope of the claims of this utility model. Furthermore, although some specific terms are used in this specification, these terms are only for convenience of explanation and do not constitute any limitation on this utility model.
Claims
1. A transformer for high-current, low-impedance short-circuit testing, characterized in that, include: The core structure includes a core column and a yoke. The core column includes an upper core column and a lower core column. The upper core column and the lower core column are disconnected to form an air gap space. The air gap space is filled with an epoxy laminate. A coil structure is sleeved on the iron core column; the coil structure includes a high-voltage winding and a low-voltage winding, and the high-voltage winding and the low-voltage winding are connected in series or in parallel to achieve different output voltages; The support frame includes an outer frame and an inner reinforcing mechanism. The outer frame is disposed outside the core structure, and one end of the inner reinforcing mechanism is connected to the core structure, while the other end is connected to the outer frame.
2. The transformer for high-current, low-impedance short-circuit testing according to claim 1, characterized in that: The upper core column is provided with a first mounting hole, and the lower core column is provided with a second mounting hole. The first mounting hole and the second mounting hole are symmetrically distributed along the upper and lower parts of the air gap space. The core structure also includes a pull plate, which is connected to the first mounting hole via a first insulating locking member and to the second mounting hole via a second insulating locking member.
3. The transformer for high-current, low-impedance short-circuit testing according to claim 2, characterized in that: The first insulating locking member and the second insulating locking member have the same structure; The first insulating locking component includes a clamping screw, a threaded bushing, and an insulating bushing. The clamping screw is inserted into the first mounting hole and is covered with an epoxy tube. Both ends of the clamping screw are threadedly connected to the threaded bushing, and the insulating bushing is provided on the side of the threaded bushing near the core column.
4. The transformer for high-current, low-impedance short-circuit testing according to claim 1, characterized in that: The outer frame includes two parallel upper crossbeams, two parallel base supports, two parallel longitudinal supports, two parallel diagonal supports, and multiple connecting beams; wherein the two upper crossbeams, the two base supports, and the two longitudinal supports are all connected by the connecting beams. The lower ends of the two longitudinal supports are respectively connected to the rear ends of the two base supports, and the upper ends of the two longitudinal supports are respectively connected to the rear ends of the two upper crossbeams. The lower ends of the two longitudinal supports are respectively connected to the rear ends of the two base supports, and the upper ends of the two longitudinal supports are respectively connected to the rear ends of the two upper crossbeams.
5. The transformer for high-current, low-impedance short-circuit testing according to claim 4, characterized in that: The internal reinforcing mechanism includes an upper reinforcing beam, a lower reinforcing beam, and a middle reinforcing beam. The upper end of the middle reinforcing beam is connected to the upper reinforcing beam, and the lower end of the middle reinforcing beam is connected to the lower reinforcing beam, so that the internal reinforcing mechanism is in the shape of an "I". The front end of the upper reinforcing beam is connected to the core clamp located at the upper end of the core structure, and the rear end of the upper reinforcing beam is connected to the longitudinal support; the front end of the lower reinforcing beam is connected to the core clamp located at the lower end of the core structure, and the rear end of the lower reinforcing beam is connected to the longitudinal support.
6. The transformer for high-current, low-impedance short-circuit testing according to claim 1, characterized in that: The high-voltage winding includes a first sub-winding, a second sub-winding, a third sub-winding, a fourth sub-winding, a fifth sub-winding, and a sixth sub-winding; the first sub-winding, the second sub-winding, and the third sub-winding are defined as the upper half of the winding, and the fourth sub-winding, the fifth sub-winding, and the sixth sub-winding are defined as the lower half of the winding. The taps on the first, second, third, fourth, fifth, and sixth sub-windings are connected in different series or parallel combinations to form at least four different voltage levels of output.
7. The transformer for high-current, low-impedance short-circuit testing according to claim 1, characterized in that: The voltage of the first sub-winding is 1.25kV, the voltage of the second sub-winding is 1.25kV, the voltage of the third sub-winding is 3.75kV, the voltage of the fourth sub-winding is 3.75kV, the voltage of the fifth sub-winding is 1.25kV, and the voltage of the sixth sub-winding is 1.25kV; wherein, The first, second, and third sub-windings are connected in series, and the fourth, fifth, and sixth sub-windings are connected in series. The upper half of the windings is connected in series with the lower half of the windings, outputting a 12.5kV voltage. The first sub-winding is connected in parallel with the second sub-winding and then connected in series with the third sub-winding. The fifth sub-winding is connected in parallel with the sixth sub-winding and then connected in series with the fourth sub-winding. The upper half of the winding is connected in series with the lower half of the winding to output a 10kV voltage. The first, second, and third sub-windings are connected in series, and the fourth, fifth, and sixth sub-windings are connected in series. The upper half of the windings is connected in parallel with the lower half of the windings, outputting a voltage of 6.25kV. The first sub-winding is connected in parallel with the second sub-winding and then in series with the third sub-winding. The fifth sub-winding is connected in parallel with the sixth sub-winding and then in series with the fourth sub-winding. The upper half of the winding is connected in parallel with the lower half of the winding, and the output voltage is 5kV.
8. The transformer for high-current, low-impedance short-circuit testing according to claim 1, characterized in that: The transformer for high-current, low-impedance short-circuit testing also includes a copper busbar structure, which is connected in series or in parallel with the coil structure to achieve different output voltages.
9. The transformer for high-current, low-impedance short-circuit testing according to claim 8, characterized in that: The copper busbar structure includes a first copper busbar, a second copper busbar, and an output copper busbar; The low-voltage winding includes an upper low-voltage winding and a lower low-voltage winding, the upper low-voltage winding and the lower low-voltage winding are connected in series; the upper low-voltage winding is connected to the first copper busbar, and the lower low-voltage winding is connected to the second copper busbar. One end of the output copper busbar is connected to the first copper busbar, and the other end of the output copper busbar is provided with a user terminal.
10. The transformer for high-current, low-impedance short-circuit testing according to claim 8, characterized in that: The copper busbar structure includes a first copper busbar, a second copper busbar, and an output copper busbar; The low-voltage winding includes an upper low-voltage winding and a lower low-voltage winding, wherein the upper low-voltage winding and the lower low-voltage winding are connected in parallel; the upper low-voltage winding is connected to the first copper busbar, and the lower low-voltage winding is connected to the second copper busbar. One end of the output copper busbar is connected to both the first copper busbar and the second copper busbar, and the other end of the output copper busbar is provided with a user terminal.