A partial discharge test apparatus and test method

Abstract

This invention discloses a partial discharge testing device, relating to the field of transformer technology, applied to the main winding of a transformer, comprising: a voltage regulating winding and a power supply assembly; the voltage regulating winding has a connecting end, an adjusting end, and a voltage regulating terminal, the connecting end being used to connect to a sub-winding in the main winding; the power supply assembly includes: a power supply, a first wire, a pluggable sleeve, and a second wire; the pluggable sleeve is disposed through the peripheral wall of the oil tank, the first end of the pluggable sleeve being connected to the sub-winding via the first wire, and the second end of the pluggable sleeve being detachably connected to the power supply for providing input voltage via the second wire; wherein, the adjusting terminal is connected to the adjusting end, so that the number of test turns of the voltage regulating winding is less than the number of turns of the sub-winding, so that the input voltage is converted into a test voltage, thereby causing partial discharge in the sub-winding. By setting up the voltage regulating winding and the power supply assembly, the partial discharge test of the sub-winding can be completed. This invention also discloses a test method using the above-mentioned testing device.

Description

Technical Field

[0001] This invention relates to the field of transformer technology, and in particular to a test device and test method for partial discharge. Background Technology

[0002] Under a certain applied voltage, in areas with a strong electric field, static charges first undergo electrostatic ionization at locations with weak insulation, but insulation breakdown does not occur. This phenomenon of static charge flow is called partial discharge; this phenomenon of partial discharge also frequently occurs in transformers.

[0003] During long-term operation, some weak points in the internal insulation of a transformer may experience partial discharge under high field strength, leading to a decrease in insulation. Under the long-term effect of severe partial discharge, it may even cause breakdown, resulting in damage to the transformer.

[0004] To investigate the impact of partial discharge in the main winding of a transformer on the transformer, it is necessary to use test equipment to induce partial discharge in the main winding and record the test data. However, traditional test equipment only has the function of recording test data and does not have the function of inducing partial discharge in the main winding. Summary of the Invention

[0005] In view of this, the present invention provides a partial discharge test device that uses a voltage regulating winding to convert the input low voltage into a test voltage to induce partial discharge in the main winding.

[0006] The present invention also provides a test method including the test equipment for partial discharge described above.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A partial discharge testing device, applied to the main winding of a transformer, includes: a voltage regulating winding and a power supply assembly;

[0009] The voltage regulating winding located in the oil tank of the transformer has a connecting end, an adjusting end, and a voltage regulating terminal. The connecting end is used to connect to a sub-winding in the main winding.

[0010] The power supply assembly includes: a first conductor, a pluggable sleeve, a second conductor, and a power source located outside the oil tank of the transformer;

[0011] The plug-in sleeve is disposed through the peripheral wall of the oil tank. The first end of the plug-in sleeve extends into the oil tank and is connected to the sub-winding through the first wire. The second end of the plug-in sleeve extends out of the oil tank and is detachably connected to the power supply for providing input voltage through the second wire.

[0012] Specifically, by adjusting the connection between the voltage regulating terminal and the regulating end, the number of test turns of the voltage regulating winding is less than the number of turns of the sub-winding, so that the input voltage is converted into a test voltage, thereby causing partial discharge in the sub-winding.

[0013] Preferably, the second end of the plug-in sleeve is a plug-in end, and the second wire can be plugged into and plugged into the plug-in end; and / or

[0014] The power supply assembly also includes an insulating cap for sealing the second end of the plug-in sleeve.

[0015] Preferably, the insertion sleeve is disposed through a protrusion on the peripheral wall of the oil tank.

[0016] Preferably, the power supply assembly further includes a sealing cavity for sealing the protrusion, and the cavity of the sealing cavity is capable of accommodating the second end of the insertion sleeve.

[0017] Preferably, the number of voltage regulating windings is multiple, and the number of power supply components is multiple;

[0018] The multiple sets of voltage regulating windings are matched one-to-one with the multiple sets of power supply components to cause partial discharge in the corresponding sub-windings of the main winding.

[0019] Preferably, a switch is provided between the connection end and the sub-winding.

[0020] Preferably, the connecting end of the voltage regulating winding is used to connect to the grid-side winding in the main winding.

[0021] Preferably, the connecting end of the voltage regulating winding is used to connect to the valve-side winding in the main winding.

[0022] Preferably, the first conductor is a stranded copper wire.

[0023] A method for testing partial discharge, using the aforementioned testing equipment, includes the following steps:

[0024] S1: Provide input voltage to the voltage regulating winding of the test equipment through the power supply of the test equipment;

[0025] S2: By adjusting the voltage regulating terminals of the test equipment, the voltage of the sub-winding of the transformer is increased;

[0026] S3: When the voltage of the sub-winding rises to the test voltage, the sub-winding experiences partial discharge, and test data on component damage to the transformer is recorded when partial discharge occurs.

[0027] As can be seen from the above technical solution, the partial discharge test equipment provided by the present invention can complete the partial discharge test of the sub-winding by setting up the voltage regulating winding and the power supply component. Moreover, the test device has a simple circuit and simple structure, which facilitates its subsequent production, manufacturing and promotion.

[0028] The present invention also provides a method for testing partial discharge. Since the above-mentioned test equipment is used, it has corresponding beneficial effects, which can be referred to the previous description and will not be repeated here. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 A schematic diagram of the circuit principle of the test equipment provided in the embodiments of the present invention;

[0031] Figure 2 A schematic diagram of the circuit principle of the hidden switch of the test equipment provided in the embodiment of the present invention;

[0032] Figure 3 This is a schematic diagram of the first structure of the test equipment and transformer provided in an embodiment of the present invention;

[0033] Figure 4 This is a schematic diagram of the second structure of the test equipment and transformer provided in an embodiment of the present invention.

[0034] 1 is the voltage regulating winding, 11 is the voltage regulating terminal, 2 is the power supply assembly, 21 is the first wire, 22 is the plug-in sleeve, 23 is the second wire, 24 is the insulating cap, and 25 is the sealing cavity.

[0035] 3 is the main winding, 31 is the grid-side winding, and 32 is the valve-side winding;

[0036] 4 represents the fuel tank, and 41 represents the protrusion. Detailed Implementation

[0037] To facilitate understanding of this technical solution, the main winding of the transformer will be explained below.

[0038] Definitions:

[0039] The main winding of a transformer is the winding that carries the main electrical charge in the transformer. It plays an important role in the circuit. It is usually made of copper wire or copper strip and tightly wound around the transformer core. The main winding is responsible for the power conversion in the transformer, turning the high voltage in the main circuit into a low voltage. It is one of the most critical components of the transformer.

[0040] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] The partial discharge testing equipment provided in this embodiment of the invention is applied to the main winding 3 of a transformer, such as... Figures 1-4 As shown, it includes: a voltage regulating winding 1 and a power supply assembly 2;

[0042] The voltage regulating winding 1 located in the oil tank 4 of the transformer has a connection end, an adjustment end and a voltage regulating terminal 11. The connection end is used to connect to a sub-winding in the main winding 3.

[0043] Power supply assembly 2 includes: a first conductor 21, a pluggable sleeve 22, a second conductor 23, and a power source located outside the transformer tank 4;

[0044] The plug-in sleeve 22 is disposed through the peripheral wall of the oil tank 4. The first end of the plug-in sleeve 22 extends into the oil tank 4 and is connected to the sub-winding through the first wire 21. The second end of the plug-in sleeve 22 extends out of the oil tank 4 and is detachably connected to the power supply for providing input voltage through the second wire 23.

[0045] The voltage regulating terminal 11 is connected to the regulating terminal so that the number of test turns of the voltage regulating winding 1 is less than the number of turns of the sub-winding, so that the input voltage is converted into the test voltage, thereby causing partial discharge in the sub-winding.

[0046] In the above technical solution, the power supply input voltage to the voltage regulating winding 1 is low voltage. The low voltage input is converted by the voltage regulating winding 1 and manifests as high voltage on the sub-winding. When the high voltage reaches the test voltage required for partial discharge, a partial discharge test occurs on the sub-winding.

[0047] Compared with existing technologies, this solution can complete the partial discharge test of the sub-winding using the voltage regulating winding 1 and the power supply component 2. Moreover, the test device has a simple circuit and structure, which facilitates its subsequent production, manufacturing and promotion.

[0048] In the above technical solutions, such as Figures 3-4As shown, the voltage regulating winding 1 is placed inside the oil tank 4 for easy manufacturing; the power supply is placed outside the oil tank 4. When a partial discharge test is required, it is connected to the power supply in sequence through the second wire 23, the plug-in sleeve 22, and the first wire 21; when a partial discharge test is not required, the power supply is disconnected and removed without affecting the normal use of the transformer.

[0049] In the above technical solution, the first conductor 21 is located inside the oil tank 4, and the second conductor 23 is located outside the oil tank 4. This arrangement facilitates the overall manufacturing of the transformer. Of course, in some implementations, the power supply is directly connected to the plug-in bushing 22, thereby providing the input voltage for the partial discharge test. In addition, the adjustment terminal has multiple adjustment interfaces for easy adjustment.

[0050] As a preferred option, such as Figure 3 As shown, the second end of the plug-in sleeve 22 is a plug-in end, and the second wire 23 can be plugged into and plugged into the plug-in end. The plug-in end allows for quick connection between the second wire 23 and the plug-in sleeve 22; and / or

[0051] like Figure 4 As shown, the power supply assembly 2 also includes an insulating cap 24 for sealing the second end of the plug-in sleeve 22. When a partial discharge test is not required, the insulating cap 24 seals the plug-in end of the plug-in sleeve 22 to prevent damage caused by moisture and extend the service life of the plug-in sleeve 22.

[0052] As a preferred option, such as Figure 3 and Figure 4 As shown, the plug-in sleeve 22 passes through the protrusion 41 on the peripheral wall of the oil tank 4. Of course, the protrusion 41 is formed by the outward protrusion of the peripheral wall of the oil tank 4; this arrangement helps to extend and make the connection structure between the plug-in sleeve 22 and the oil tank 4 more secure.

[0053] Furthermore, such as Figure 4 As shown, the power supply assembly 2 also includes a sealing cavity 25 for sealing the protrusion 41, and the cavity of the sealing cavity 25 can accommodate the second end of the plug-in sleeve 22. The sealing cavity 25 serves to isolate moisture and dust. When a partial discharge test is not required, the sealing cavity 25 can be used to seal the protrusion 41.

[0054] Specifically, such as Figures 3-4 As shown, there are multiple sets of voltage regulating winding 1 and multiple sets of power supply components 2;

[0055] Multiple sets of voltage regulating windings 1 are matched one-to-one with multiple sets of power supply components 2 to cause partial discharge in the corresponding sub-windings in the main winding 3.

[0056] In the above technical solution, the transformer has three sub-windings, the voltage regulating winding 1 has three sets, and the power supply component 2 has three sets.

[0057] Specifically, such as Figure 1 As shown, a switch is provided between the connection terminal and the sub-winding. When a partial discharge test is not required, the connection between the connection terminal and the sub-winding can be disconnected, and the transformer can be operated normally.

[0058] Specifically, the connecting end of the voltage regulating winding 1 is used to connect to the grid-side winding 31 in the main winding 3.

[0059] In the above technical solution, the transformer is a flexible DC transformer. Through the voltage regulating winding 1 and the grid-side winding 31, partial discharge can occur in the grid-side winding 31.

[0060] Specifically, the connecting end of the voltage regulating winding 1 is used to connect to the valve-side winding 32 in the main winding 3.

[0061] In the above technical solution, the transformer is a flexible DC transformer. Through the voltage regulating winding 1 and the valve-side winding 32, partial discharge can be generated in the valve-side winding 32.

[0062] Specifically, the first conductor 21 is a soft copper stranded wire, which helps to save the cost of the test equipment.

[0063] This invention also discloses a method for testing partial discharge, using the aforementioned testing equipment, comprising the following steps:

[0064] S1: The power supply of the test equipment provides the input voltage to the voltage regulating winding 1 of the test equipment;

[0065] S2: By adjusting the voltage regulating terminal 11 of the test equipment, the voltage of the transformer sub-winding is increased;

[0066] S3: When the voltage of the sub-winding rises to the test voltage, partial discharge occurs in the sub-winding. Record the test data of the transformer component damage when partial discharge occurs.

[0067] The technical features mentioned above, those to be mentioned below, and those shown individually in the accompanying drawings can be combined arbitrarily, provided that the combined technical features are not contradictory. All feasible combinations of features are the technical content explicitly described herein. Any one of the multiple sub-features contained in the same statement can be applied independently, without necessarily being applied together with other sub-features.

[0068] The following is a further description of this solution with reference to specific embodiments:

[0069] In this technical solution, the test tap scheme consists of a voltage regulating winding 1, a first conductor 21 (soft copper stranded wire), and a grid-side winding 31. A test tap (i.e., the first conductor 21) is led out from the tap changer terminal and connected to the test equipment for field partial discharge testing (IVPD).

[0070] The cable termination arrangement consists of a voltage regulating winding 1, a test tap (i.e., the first conductor 21), a plug-in sleeve 22, and a test cable (i.e., the second conductor 23). The cable termination arrangement involves the first conductor 21 (soft copper stranded wire) being led out from the voltage regulating winding 1 and connected to the plug-in sleeve 22. After the plug-in sleeve 22 is connected to the second conductor 23, the second conductor 23 is then connected to the power supply for partial discharge testing.

[0071] The cable termination protection arrangement consists of a plug-in sleeve 22, an insulating cap 24, a sealing cavity 25, and the transformer tank 4. The cable termination protection arrangement structure involves removing the second conductor 23 used for power connection after a partial discharge test, sealing the plug-in sleeve 22 with the insulating cap 24, and then further protecting it with the sealing cavity 25. The sealing cavity 25 is fixed to the transformer tank 4, has a corrosion resistance rating of CX, is constructed of welded steel plates, and is painted both internally and externally, providing dustproof and waterproof functions, with performance equivalent to IP56.

[0072] This invention utilizes an external test tap on the voltage regulating winding. The insulation level of the first conductor 21 is the same as that of the neutral point on the grid side. The lightning impulse insulation level of the neutral point on the grid side is 185kV, converted to DIL 70kV, which is less than its short-time AC applied voltage of 95kV. For the AC (95kV) electric field check in oil, the maximum electric field strength of the first conductor 21 is 1.49kV / mm, with a safety margin of 4.06. For the AC (95kV) electric field check at the air end of the plug-in bushing 22 (the end connected to the second conductor 23), the maximum electric field strength is 4.777kV / mm, and the safety margin at the terminal of the plug-in bushing 22 (the end connected to the first conductor 21) is 6.76, fully meeting the design requirements. This scheme has a low risk of external short-circuit faults, and the test device occupies a small volume, reducing both direct costs and indirect economic losses.

[0073] It should be noted that the main winding 3 can be divided into a primary winding and a secondary winding. The main winding 3 can also be divided into a high-voltage winding and a low-voltage winding. They are just different names, but they can all be subjected to partial discharge tests using this test equipment.

[0074] This invention can be used not only on flexible DC transformers, but also on converter transformers and AC transformers.

[0075] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0076] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A partial discharge testing device, applied to the main winding (3) of a transformer, characterized in that, include: Voltage regulating winding (1) and power supply assembly (2); The voltage regulating winding (1) located in the oil tank (4) of the transformer has a connection end, an adjustment end and a voltage regulating terminal (11), the connection end being used to connect to a sub-winding in the main winding (3); The power supply assembly (2) includes: a first conductor (21), a plug-in sleeve (22), a second conductor (23), and a power source located outside the oil tank (4) of the transformer; The plug-in sleeve (22) is disposed through the peripheral wall of the oil tank (4). The first end of the plug-in sleeve (22) extends into the oil tank (4) and is connected to the sub-winding through the first wire (21). The second end of the plug-in sleeve (22) extends out of the oil tank (4) and is detachably connected to the power supply for providing input voltage through the second wire (23). The voltage regulating terminal (11) is connected to the regulating end so that the number of test turns of the voltage regulating winding (1) is less than the number of turns of the sub-winding, so that the input voltage is converted into a test voltage, thereby causing partial discharge in the sub-winding.

2. The testing equipment according to claim 1, characterized in that, The second end of the plug-in sleeve (22) is the plug-in end, and the second wire (23) can be plugged into and plugged into the plug-in end; and / or The power supply assembly (2) further includes an insulating cap (24) for sealing the second end of the plug sleeve (22).

3. The testing equipment according to claim 1, characterized in that, The insertion sleeve (22) passes through the protrusion (41) on the peripheral wall of the oil tank (4).

4. The testing equipment according to claim 3, characterized in that, The power supply assembly (2) further includes a cover cavity (25) for sealing the protrusion (41), and the cavity of the cover cavity (25) is capable of accommodating the second end of the plug-in sleeve (22).

5. The testing equipment according to claim 1, characterized in that, The number of voltage regulating windings (1) is multiple, and the number of power supply components (2) is multiple; Multiple sets of voltage regulating windings (1) are matched one-to-one with multiple sets of power supply components (2) to cause partial discharge in the corresponding sub-windings of the main winding (3).

6. The testing equipment according to claim 1, characterized in that, A switch is provided between the connection end and the sub-winding.

7. The testing equipment according to claim 1, characterized in that, The connection end of the voltage regulating winding (1) is used to connect to the mesh-side winding (31) in the main winding (3).

8. The testing equipment according to claim 1, characterized in that, The connecting end of the voltage regulating winding (1) is used to connect to the valve side winding (32) in the main winding (3).

9. The testing equipment according to claim 1, characterized in that, The first conductor (21) is a soft copper stranded wire.

10. A method for testing partial discharge, using the testing equipment as described in any one of claims 1-9, comprising the steps of: S1: The power supply of the test equipment provides the input voltage to the voltage regulating winding (1) of the test equipment; S2: By adjusting the voltage regulating terminal (11) of the test equipment, the voltage of the sub-winding of the transformer is increased; S3: When the voltage of the sub-winding rises to the test voltage, the sub-winding experiences partial discharge, and test data on component damage to the transformer is recorded when partial discharge occurs.

Images