Power transformer turn-to-turn short circuit fault test bench
By designing the power transformer inter-turn short-circuit fault test bench, the problem of difficult reproducing inter-turn short-circuit fault tests and high operational difficulty in the prior art is solved, and the transformer performance is accurately detected in the actual working environment, improving the fault resistance and reliability.
Patent Information
- Application Number
- CN202421120503.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-21
- Publication Date
- 2025-06-20
- Estimated Expiration
- 2034-05-21
AI Technical Summary
The prior art is difficult to effectively conduct experimental research on power transformer interturn short circuit faults, mainly because the interturn short circuit fault transients are difficult to reproduce, and the test operation is difficult and costly.
A power transformer inter-turn short-circuit fault test bench is designed, including a voltage regulator, power transformer, power analysis system and temperature measurement system. By artificially setting inter-turn short-circuit defects, inter-turn short-circuit test is carried out in the actual working environment of the transformer.
It realizes accurate and effective inter-turn short-circuit tests in the actual working environment of the transformer, and can more accurately detect the working status and performance of the transformer, identify potential design defects or performance shortcomings, and improve the transformer's fault resistance and reliability.
Smart Images
Figure CN223006290U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the field of power transformers, in particular to a test bench for inter-turn short-circuit faults of power transformers. Background Technique
[0002] Inter-turn short-circuit faults in transformer windings are the most common fault types in power transformers. Inter-turn short circuits will cause an increase in the short-circuit current of the transformer winding. This short-circuit current will generate huge active power losses, and ultimately will lead to the destruction of the transformer insulation and even cause the transformer to burn out, resulting in power supply interruption accidents. The test bench for inter-turn short-circuit faults of power transformers can conduct inter-turn short-circuit tests by simulating the actual working environment of the transformer, and can deeply understand the working state and performance of the transformer under such fault conditions. Through the analysis of the test results, potential design defects or performance shortcomings can be identified, and the design can be improved accordingly to improve the fault resistance and reliability of the transformer.
[0003] At present, the research on inter-turn short-circuit faults in power transformer windings mainly focuses on the diagnosis of the inter-turn insulation state of the windings and the protection methods during faults, but there is less experimental research on inter-turn short-circuit faults in transformers. The main reason is that the transient state of inter-turn short-circuit faults in transformers is difficult to reproduce, and inter-turn short-circuit faults may cause more serious faults, with high test operation difficulty and cost. Content of the Utility Model
[0004] The purpose of the utility model is to provide a test bench for inter-turn short-circuit faults of power transformers to overcome the defects existing in the above-mentioned prior art.
[0005] The purpose of the utility model can be realized by the following technical solutions:
[0006] The utility model provides a test bench for inter-turn short-circuit faults of power transformers, including: a voltage regulator, a power transformer, a power analysis system, and a temperature measurement system;
[0007] The power transformer includes: three-phase high-voltage bushings, three-phase low-voltage bushings, high-voltage lead-out wires, low-voltage lead-out wires, three-phase high-voltage windings, three-phase low-voltage windings, a magnetic core, and an oil tank; the three-phase high-voltage bushings and the three-phase low-voltage bushings are at the top of the oil tank, and the three-phase high-voltage bushings are connected to the three-phase high-voltage windings through high-voltage lead-out wires; the three-phase low-voltage bushings are connected to the three-phase low-voltage windings through low-voltage lead-out wires; both the three-phase high-voltage windings and the three-phase low-voltage windings are wound around the magnetic core, and the three-phase high-voltage windings are outside the three-phase low-voltage windings;
[0008] Among them, the voltage regulator is connected to the three-phase high-voltage bushings and accesses three-phase alternating current for power supply to the transformer; the three-phase high-voltage windings and the three-phase low-voltage windings are connected to a power analyzer, and the power analysis system is used to measure the currents of the high-voltage and low-voltage windings of the transformer;
[0009] The power transformer is connected to the temperature measurement system; the temperature measurement system is used to measure the temperature of the transformer.
[0010] The winding arrangement of the three-phase high-voltage bushings is the same as that of the three-phase low-voltage bushings.
[0011] The three-phase high-voltage bushings include a first high-voltage bushing, a second high-voltage bushing, and a third high-voltage bushing; the first high-voltage bushing is located at the lower left side of the top cover of the oil tank, the second high-voltage bushing is located at the middle lower side of the top cover of the oil tank, and the third high-voltage bushing is located at the lower right side of the top cover of the oil tank, and their winding arrangements are the same.
[0012] The three-phase low-voltage bushings are located between the first high-voltage bushing and the second high-voltage bushing.
[0013] The three-phase low-voltage bushings include a first low-voltage bushing, a second low-voltage bushing, and a third low-voltage bushing; the first low-voltage bushing is located at the upper left side of the top cover of the oil tank, the second low-voltage bushing is located at the middle upper side of the top cover of the oil tank, and the third low-voltage bushing is located at the upper right side of the top cover of the oil tank, and their winding arrangements are the same.
[0014] The three-phase high-voltage windings are connected in star.
[0015] The three-phase low-voltage windings are connected in star.
[0016] The three-phase high-voltage windings have a total of three tap joints. The first tap joint is located at the end of the high-voltage winding; the second tap joint is spaced from the first tap joint by a first set number of turns; the third tap joint is spaced from the first tap joint by a second set number of turns, where the second set number of turns is more than the first set number of turns.
[0017] Further, after short-circuiting the second tap joint and the third tap joint, the winding in the middle of the two is set as the faulty turn winding.
[0018] The power analysis system includes a power analyzer.
[0019] The temperature measurement system includes an infrared thermal imager, and the infrared thermal imager is installed at a position 1.5 m away from the transformer.
[0020] Compared with the prior art, the present utility model has the following beneficial effects:
[0021] 1. For this transformer inter-turn short-circuit test bench, by artificially setting inter-turn short-circuit defects and conducting inter-turn short-circuit tests in the actual working environment of the transformer, when experimental testers conduct different detection experiments, they can obtain more accurate and effective detection effects, and the test bench also has good controllability.
[0022] 2. The main transformer test bench for electric locomotives can be adjusted and adapted according to different types of transformers, with strong versatility and flexibility. Description of the Drawings
[0023] Figure 1 Schematic diagram of the test bench provided by an embodiment of the present utility model;
[0024] Figure 2 Schematic diagram of the structure of the transformer provided by an embodiment of the present utility model;
[0025] Figure 3 Schematic diagram of the tap connection of one-phase winding of the transformer provided by an embodiment of the present utility model;
[0026] Among them, 1. The first high-voltage bushing, 2. The second high-voltage bushing, 3. The third high-voltage bushing, 4. The first low-voltage bushing, 5. The second low-voltage bushing, 6. The third low-voltage bushing, 7. High-voltage lead wire, 8. Low-voltage lead wire, 9. The first high-voltage winding, 10. The second high-voltage winding, 11. The third high-voltage winding, 12. The first low-voltage winding, 13. The second low-voltage winding, 14. The third low-voltage winding, 15. The magnetic core, 16. The oil tank. Detailed Embodiment
[0027] The present utility model will be described in detail below with reference to the drawings and specific embodiments. This embodiment is implemented on the premise of the technical solution of the present utility model, and the detailed implementation manner and specific operation process are given, but the protection scope of the present utility model is not limited to the following embodiments.
[0028] As Figure 1 shown, the present utility model provides a test bench for inter-turn short-circuit faults of power transformers, including a voltage regulator, a power transformer, a power analysis system for measuring the currents of the high- and low-voltage windings of the transformer, and a temperature measurement system for measuring the temperature of the transformer. Among them, the voltage regulator is connected to the power transformer, and the power transformer is respectively connected to the temperature measurement system and the power analyzer.
[0029] Specifically, as Figure 2 shown, the power transformer provided by an embodiment of the present utility model includes: the first high-voltage bushing 1, the second high-voltage bushing 2, the third high-voltage bushing 3; the first low-voltage bushing 4, the second low-voltage bushing 5, the third low-voltage bushing 6; the high-voltage lead wire 7; the low-voltage lead wire 8; the first high-voltage winding 9, the second high-voltage winding 10, the third high-voltage winding 11; the first low-voltage winding 12, the second low-voltage winding 13, the third low-voltage winding 14; the magnetic core 15; the oil tank 16.
[0030] The three-phase high-voltage bushings include a first high-voltage bushing 1, a second high-voltage bushing 2, and a third high-voltage bushing 3; the first high-voltage bushing 1 is located at the lower left side of the top cover of the oil tank, the second high-voltage bushing 2 is located at the middle lower side of the top cover of the oil tank, and the third high-voltage bushing 3 is located at the lower right side of the top cover of the oil tank. Their winding arrangements are the same and they are equally spaced; the first low-voltage bushing 4, the second low-voltage bushing 5, and the third low-voltage bushing 6 are between the first high-voltage bushing 1 and the second high-voltage bushing 2.
[0031] The three-phase low-voltage bushings include a first low-voltage bushing 4, a second low-voltage bushing 5, and a third low-voltage bushing 6; the first low-voltage bushing 4 is located at the upper left side of the top cover of the oil tank, the second low-voltage bushing 5 is located at the middle upper side of the top cover of the oil tank, and the third low-voltage bushing 6 is located at the upper right side of the top cover of the oil tank. Their winding arrangements are the same.
[0032] In this embodiment, the winding arrangements of the three-phase high-voltage bushings are the same as those of the three-phase low-voltage bushings.
[0033] The first high-voltage bushing 1 is connected to the first high-voltage winding 9 through a high-voltage lead wire 7. Similarly, the second high-voltage bushing 2 is connected to the second high-voltage winding 10 through a high-voltage lead wire 7; the third high-voltage bushing 3 is connected to the third high-voltage winding 11 through a high-voltage lead wire 7; similar to the principle of connecting the high-voltage bushing to the high-voltage winding, the first, second, and third low-voltage bushings are respectively connected to the first, second, and third low-voltage windings through low-voltage lead wires 8.
[0034] Preferably, the three-phase high-voltage windings in this embodiment are star-connected.
[0035] Preferably, the three-phase low-voltage windings in this embodiment are delta-connected.
[0036] The structure of the magnetic core 15 includes: a magnetic core body, two windows, and three side columns. Among them, the three side columns are the first side column, the second side column, and the third side column. The first high-voltage winding 9 and the first low-voltage winding 12 are provided on the first side column. Similarly, the second high-voltage winding 10 and the second low-voltage winding 13 are provided on the second side column, and the third high-voltage winding 11 and the third low-voltage winding 14 are provided on the third side column. Specifically, the high-voltage windings are all wound around the outside of the low-voltage windings.
[0037] Within a set range at the bottom of the high-voltage winding, a faulty turn winding is also provided. In this test platform, in this embodiment, a short-circuit fault is set by short-circuiting the second tap P5 and the third tap P6 of the high-voltage winding of the transformer, and the short-circuited winding is the faulty turn winding.
[0038] The entire magnetic core 15, as well as the high-voltage winding and the low-voltage winding, are all within the oil tank 16.
[0039] Such as Figure 3As shown in the figure, the tap connection schematic diagram of one phase winding of the transformer provided by the embodiment of the present utility model includes: the low-voltage winding lead-out point P1, the low-voltage winding neutral point P2; the high-voltage winding neutral point P3, the first tap P4 of the high-voltage winding, the second tap P5 of the high-voltage winding, and the third tap P6 of the high-voltage winding. When the transformer is working, by adjusting the switch to connect different taps, the effective number of turns of the high-voltage winding will also be different. Among them, the first tap P4 is located at the end of the high-voltage winding. When this tap is connected, the number of turns of the high-voltage winding is 814 turns, and the corresponding transformer turns ratio is 10500V:400V; the second tap P5 is separated from the first tap P4 by 39 turns. When this tap is connected, the number of turns of the high-voltage winding is 775 turns, and the corresponding transformer turns ratio is 10000V:400V; the third tap P6 is separated from the first tap P4 by 78 turns. When this tap is connected, the number of turns of the high-voltage winding is 736 turns, and the corresponding transformer turns ratio is 9500V:400V.
[0040] In this embodiment, a 315KVA / 10KV three-phase double-winding oil-immersed power transformer is used for test analysis. The low-voltage winding of the transformer has a total of 31 turns, and the high-voltage winding has a total of 814 turns. The oil in the transformer mainly plays a role in heat dissipation and cooling during operation and does not affect the magnitude of the short-circuit current when the transformer has an inter-turn short-circuit fault. In order to facilitate the test to set a short circuit, measure the short-circuit current and winding temperature rise, the oil-immersed transformer is dried and the oil is removed.
[0041] In this embodiment, the second tap P5 and the third tap P6 of one phase of the high-voltage winding of the transformer are short-circuited for the test, and the first tap P4 is energized to realize the setting of a 39-turn inter-turn short-circuit fault of the transformer. When the first low-voltage bushing 4, the second low-voltage bushing 5, and the third low-voltage bushing 6 connected to the three-phase low-voltage winding are short-circuited and the first low-voltage bushing 4, the second low-voltage bushing 5, and the third low-voltage bushing 6 connected to the three-phase low-voltage winding are open-circuited, the input voltage of the high-voltage bushing of the power transformer is gradually increased until the three-phase voltage of the high-voltage winding of the transformer is 380V.
[0042] In this embodiment, the voltage regulator is connected to the high-voltage bushing of the transformer to supply power to the transformer; the power analysis system is a power analyzer, and the voltages and currents of the high- and low-voltage windings of the transformer are connected to the corresponding input ports of the power analyzer; in this embodiment, when an inter-turn short-circuit fault occurs in the high-voltage winding of the transformer, the short-circuit turn current will increase sharply, and the current of the corresponding fault phase will be higher than that of the other two phases. The corresponding temperature measurement system is an infrared thermal imager, and the infrared thermal imager measures at a distance of 1.5m from the transformer.
[0043] Optionally, according to actual needs, a resistance temperature detector or a thermocouple can also be selected as the temperature sensor wound on the winding of the transformer. Since the inter-turn short circuit fault of the transformer will cause an increase in the winding current, the temperature sensor can detect the temperature rise change of the faulty turn winding of the transformer after the inter-turn short circuit fault occurs, and the analysis result can provide a reference for the online detection of the inter-turn short circuit fault of the transformer.
[0044] The preferred specific embodiments of the present invention have been described in detail above. It should be understood that those of ordinary skill in the art can make many modifications and variations according to the concept of the present invention without creative labor. Therefore, all technical solutions that can be obtained by those skilled in the art in the technical field based on the concept of the present invention through logical analysis, reasoning or limited experiments on the basis of the prior art should be within the protection scope determined by the claims.
Claims
1. A power transformer turn-to-turn short-circuit fault test bench, characterized in that: include: Voltage regulators, power transformers, power analysis systems, and temperature measurement systems; The power transformer comprises: a three-phase high-voltage bushing, a three-phase low-voltage bushing, a high-voltage lead-out wire, a low-voltage lead-out wire, a three-phase high-voltage winding, a three-phase low-voltage winding, a magnetic core and an oil tank; the three-phase high-voltage bushing and the three-phase low-voltage bushing are at the top of the oil tank, the three-phase high-voltage bushing is connected to the three-phase high-voltage winding through the high-voltage lead-out wire; the three-phase low-voltage bushing is connected to the three-phase low-voltage winding through the low-voltage lead-out wire; the three-phase high-voltage winding and the three-phase low-voltage winding are both wound around the magnetic core, and the three-phase high-voltage winding is outside the three-phase low-voltage winding; The voltage regulator is connected to the three-phase high-voltage bushing and connected to the three-phase alternating current to power the transformer; the three-phase high-voltage winding and the three-phase low-voltage winding are connected to the power analyzer, and the power analysis system is used to measure the high and low voltage winding currents of the transformer; The power transformer is connected to a temperature measurement system, and the temperature measurement system is a temperature measurement system for measuring the temperature of the transformer.
2. A power transformer turn-to-turn short-circuit fault test bench according to claim 1, characterized in that: The winding arrangement of the three-phase high-voltage bushing is consistent with that of the three-phase low-voltage bushing.
3. A power transformer turn-to-turn short-circuit fault test bench according to claim 2, characterized in that: The three-phase high-voltage bushing includes a first high-voltage bushing, a second high-voltage bushing, and a third high-voltage bushing; the first high-voltage bushing is located on the lower left side of the fuel tank top cover, the second high-voltage bushing is located on the lower middle side of the fuel tank top cover, and the third high-voltage bushing is located on the lower right side of the fuel tank top cover, and the winding arrangement of the three is consistent.
4. A power transformer turn-to-turn short-circuit fault test bench according to claim 3, characterized in that: The three-phase low-voltage bushing is located between the first high-voltage bushing and the second high-voltage bushing.
5. The power transformer inter-turn short-circuit fault test bench according to claim 4 is characterized in that: The three-phase low-voltage bushing includes a first low-voltage bushing, a second low-voltage bushing, and a third low-voltage bushing; the first low-voltage bushing is located on the upper left side of the oil tank top cover, the second low-voltage bushing is located on the upper middle side of the oil tank top cover, and the third low-voltage bushing is located on the upper right side of the oil tank top cover, and the winding arrangement of the three is consistent.
6. The power transformer turn-to-turn short-circuit fault test bench according to claim 1, characterized in that: The three-phase high-voltage winding is connected in star shape, and the three-phase low-voltage winding is connected in star shape.
7. The power transformer inter-turn short-circuit fault test bench according to claim 1 is characterized in that: The three-phase high-voltage winding includes three taps, the first tap is located at the end of the high-voltage winding; the second tap is spaced apart from the first tap by a first set number of turns; the third tap is spaced apart from the first tap by a second set number of turns, wherein the second set number of turns is greater than the first set number of turns.
8. The power transformer inter-turn short-circuit fault test bench according to claim 7 is characterized in that: After the second tap and the third tap are short-circuited, the winding between the two is set as the fault turn winding.
9. The power transformer turn-to-turn short-circuit fault test bench according to claim 1, characterized in that: The power analysis system includes a power analyzer.
10. The power transformer turn-to-turn short-circuit fault test bench according to claim 1, characterized in that: The temperature measurement system includes an infrared thermal imager, which is installed at a distance of 1.5 m from the transformer.