Oil-carrying maintenance method for transformer connecting part

Abstract

The invention discloses an oil-carrying maintenance method for a transformer connecting part, which mainly comprises the following steps of: vacuumizing a transformer through a vacuum unit, temporarily plugging a pipeline by using an isolation plate while dismounting a valve to be maintained so as to prevent insulating oil from flowing out, and immediately mounting the valve back to the transformer to finish maintenance. According to the oil-carrying overhauling method for the transformer connecting part, the transformer is vacuumized through the vacuum unit, the pressure of insulating oil on the overhauling part is reduced, meanwhile, the isolation plate is adopted for temporarily blocking the dismounting part, and external foreign matter is prevented from entering the body; and the connecting part directly connected with the transformer body can be quickly disassembled and replaced, so that the maintenance time is effectively saved, and the maintenance efficiency is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of building construction and relates to an oil-carrying maintenance method for transformer connecting parts. Background Art

[0002] Oil-immersed transformer is a kind of power equipment widely used in power transmission and distribution. The coil and core of oil-immersed transformer are immersed in insulating oil, which is used as cooling and insulating medium, and is cooled by natural convection of oil, air cooling or water cooling, and forced oil circulation.

[0003] For large-capacity oil-immersed transformers, they are large in size, have many components, and are filled with a large amount of insulating oil. There are also many equipment components directly connected to the transformer body. If the connecting components directly connected to the body, such as the radiator body side flange, partial discharge online detection probe, etc., are damaged and leak oil and need to be repaired, the existing practice is to extract all the oil in the transformer before repairing or replacing it. At the same time, the related processes after the insulating oil in the transformer is extracted from the transformer are quite cumbersome and time-consuming (involving vacuuming, oil extraction, hot oil circulation, oil sample testing, etc.). In this way, not only the workload of maintenance work is increased, work efficiency is reduced, but also the maintenance time is prolonged, which is not conducive to the normal operation of the power grid and may even affect the normal electricity consumption of residents.

[0004] In order to solve the above problems, a method for repairing and replacing connecting parts without oil extraction is needed, which can save a lot of time and equipment for transformer oil extraction and injection, and greatly improve efficiency. Summary of the invention

[0005] In view of this, the present invention provides an oil-based maintenance method for transformer connecting components, in which the transformer is evacuated by a vacuum unit to reduce the pressure of the insulating oil on the maintenance part, and an isolation plate is used to temporarily block the removal part to prevent external foreign matter from entering the interior of the main body, thereby facilitating the rapid removal and replacement of the connecting components directly connected to the transformer body, effectively saving maintenance time and improving maintenance efficiency.

[0006] The present invention discloses a method for oil-treated transformer connection parts, which specifically comprises the following steps:

[0007] S1, maintenance preparation, remove the breather of the transformer, then connect the vacuum unit to the breather connection port of the transformer, open the bypass valve of the oil pillow, open the valve to be repaired, and close other valves of the transformer;

[0008] S2, start the vacuum unit, and use the vacuum unit to evacuate the transformer until the vacuum degree of the transformer reaches and remains at the first set value;

[0009] S3, shut down the vacuum unit and remove the valve to be repaired, remove the connecting bolts between the valve to be repaired and the connecting surface of the valve interface of the transformer, and insert the isolation plate while removing the bolts;

[0010] S4, the vacuum unit is turned on for the second time to perform vacuum operation. When the vacuum degree reaches the first set value again, the isolation plate is pulled out and the new valve is connected to the valve interface of the transformer;

[0011] S5, adjust the vacuum unit so that the vacuum degree of the transformer reaches the second set value, and install and tighten the connecting bolts between the valve and the valve interface;

[0012] S6, stop the vacuum unit and close the bypass valve, slowly break the vacuum until the vacuum is exhausted, disconnect the vacuum unit from the breathing apparatus connection port, and exhaust from the gas relay exhaust port until no gas is discharged;

[0013] S7, open all valves of the transformer and perform exhaust operation on the transformer;

[0014] S8, to prevent false oil level, open the oil pillow exhaust valve, inflate the capsule in the oil pillow through the transformer's breather connection port, and stop inflating when no gas is discharged from the oil pillow exhaust port, and close the valve of the oil pillow exhaust port;

[0015] S9, install the respirator, count the tools, tidy up the site, and take oil samples for testing.

[0016] Further, in step S3, the isolation plate includes an isolation plate body and an isolation membrane disposed on the isolation plate body, and the isolation membrane is made of an elastic material.

[0017] Furthermore, the isolation plate body comprises an isolation inner plate and an isolation outer plate which are overlapped with each other, and the isolation membrane is fixed between the isolation inner plate and the isolation outer plate.

[0018] Furthermore, the valve interface of the transformer has a flange joint surface, and the diameter of the isolation membrane is larger than the inner diameter of the flange joint surface and smaller than the outer diameter of the flange joint surface.

[0019] Further, in step S2, the first set value is 0.8-0.9 kPa.

[0020] Further, in step S5, the second set value is a vacuum degree greater than 0.9 kPa.

[0021] Further, in step S3, the connecting bolts are removed sequentially from top to bottom, and the isolation plates are inserted synchronously with the removal of the connecting bolts.

[0022] Beneficial effects of the present invention:

[0023] The present invention provides a method for oil-based maintenance of transformer connection parts, wherein the transformer is vacuumed by a vacuum unit to reduce the pressure of insulating oil on the maintenance part, and an isolation plate is used to temporarily block the removal part to prevent external foreign matter from entering the body, so as to facilitate the rapid removal and replacement of the connection parts directly connected to the transformer body, effectively saving maintenance time and improving maintenance efficiency. The isolation plate also ensures that the vacuum condition of the transformer can be intuitively observed during the maintenance process. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the principle of the present invention;

[0025] Figure 2 for Figure 1 A partial enlarged view of the middle A;

[0026] Figure 3 A front view of a separator of the present invention;

[0027] Figure 4 for Figure 3 Cross-sectional view at BB in the middle. DETAILED DESCRIPTION

[0028] It should be noted that in the description of this specification, the terms "upper", "lower", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential" and the like indicate the orientation or position relationship based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. In this embodiment, the valve is inspected and replaced, but the method is also applicable to the inspection and replacement of other connecting parts directly connected to the transformer body.

[0029] As shown in the figure, the present invention discloses a method for oil-in-oil maintenance of transformer connection components, which specifically includes the following steps:

[0030] S1, maintenance preparation, prepare a vacuum unit 2 on site, connect the power supply of vacuum unit 2, and ground it; remove the respirator of transformer 1, connect the vacuum unit 2 to the respirator connection port of transformer 1, open the bypass valve of the oil pillow, open the valve 4 to be repaired, and close the other valves of transformer 1 to keep one air chamber;

[0031] S2, start the vacuum unit 2, use the vacuum unit 2 to evacuate the transformer 1 until the vacuum degree of the transformer 1 reaches and is maintained at a first set value of 0.8-0.9 kPa. When the vacuum degree is greater than 0.9 kPa, the suction force is too large and the parts cannot be removed. When the vacuum degree is less than 0.8 kPa, the insulating oil of the removed parts will flow out. In this embodiment, the first set value is 0.8 kPa.

[0032] S3, turn off the vacuum unit 2 to avoid the vacuum degree from becoming larger, remove the connecting bolts of the connecting surface of the valve 4 to be repaired and the valve interface of the transformer 1, and insert the isolation plate 3 while removing the bolts. When removing the connecting bolts, remove them from top to bottom in sequence, and the isolation plate 3 is inserted synchronously with the removal of the connecting bolts. During actual maintenance, the flange joint surface of the valve and the flange joint surface of the valve interface of the transformer 1 will be tightly combined and the isolation plate 3 cannot be inserted. At this time, it is necessary to loosen all the connecting bolts first, and use a flat-blade screwdriver to open a small gap on the joint surface, so that the isolation plate 3 can be smoothly inserted;

[0033] The isolation plate 3 in this embodiment includes an isolation plate body 5 and an isolation membrane 6 arranged on the isolation plate body 5, and the isolation membrane 6 is made of elastic material. The isolation plate body 5 includes an isolation inner plate 7 and an isolation outer plate 8 that overlap each other, and the isolation membrane 6 is fixed between the isolation inner plate 7 and the isolation outer plate 8. The valve interface has a flange joint surface, and the diameter of the isolation membrane 6 is larger than the inner diameter of the flange joint surface and smaller than the outer diameter of the flange joint surface. In this way, after the isolation plate 3 is inserted, the isolation membrane 6 can completely cover the flange joint surface of the valve interface. In addition, when the transformer 1 is in a vacuum state, a temporary blockage can be formed on the valve interface to achieve oil maintenance. Since the transformer 1 is in a vacuum negative pressure state, using a conventional metal plate instead of the isolation plate 3 can also achieve a similar effect, but using the isolation plate 3 can ensure that the vacuum condition of the transformer 1 can be intuitively observed during the maintenance process. When the vacuum degree is within the first set value range, the isolation membrane 6 is slightly concave inward, and the vacuum degree of the transformer 1 is more intuitive.

[0034] S4, open the vacuum unit 2 for the second time to perform vacuum operation. When the vacuum degree reaches the first set value again, remove the isolation plate 3 and connect the new valve to the valve interface of the transformer 1; when the valve to be repaired is removed, the vacuum degree may be affected, so it is necessary to open the vacuum unit 2 for the second time. When the vacuum degree reaches the first set value again, remove the metal plate and quickly connect the valve. The valve here is a new valve. In order to prevent the maintenance work from affecting the normal operation of the power grid, the isolation plate 3 only plays a temporary blockage to avoid oil pumping maintenance. Therefore, when the connecting parts are repaired, the removed parts to be repaired will be replaced and installed with replacement parts. This is understandable to those skilled in the art and will not be elaborated here. The new valve here does not specifically refer to a new valve, but a spare valve with the same specifications as the valve to be repaired and functioning normally.

[0035] S5, adjust the vacuum unit 2 so that the vacuum degree of the transformer 1 reaches the second set value, that is, when it is greater than 0.9 kPa, install and tighten the connecting bolts between the valve and the valve interface; adjust the vacuum degree so that the vacuum degree is greater than 0.9 kPa, so that the valve interface can firmly absorb the valve, which is convenient for the installation and tightening of the connecting bolts. The valve here is the new valve in step S4.

[0036] S6, stop the vacuum unit 2 and close the bypass valve, slowly break the vacuum until the vacuum is exhausted, disconnect the vacuum unit 2 from the respirator connection port, and exhaust from the gas relay exhaust port until no gas is discharged; in this embodiment, the standard for judging whether there is no gas discharge is that oil is discharged from the corresponding exhaust pipe, and at this time there is no gas discharge.

[0037] S7, open all valves of transformer 1, and perform exhaust operation on transformer 1; open all valves that were previously closed, and exhaust gas from all exhaust ports of transformer 1. After the exhaust is completed, close all exhaust valves. The exhaust completion standard is the same as above and will not be repeated here.

[0038] S8, to prevent false oil level, open the exhaust valve of the oil pillow, and hang an oil receiving bucket at the exhaust valve of the oil pillow for collecting oil, fill the capsule in the oil pillow with dry air or high-purity nitrogen through the breathing device connection port of the transformer 1, so that the capsule in the oil pillow expands and the oil is discharged from the exhaust port of the oil pillow. When no gas is discharged from the exhaust port of the oil pillow, stop injecting dry air or high-purity nitrogen, and close the valve of the exhaust port of the oil pillow;

[0039] S9, install the respirator, count the tools, tidy up the site, and take oil samples for testing. If the oil sample is unqualified, circulate hot oil until it is qualified.

[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A method for oil-treated transformer connection parts, characterized in that: The method specifically comprises the following steps: S1, maintenance preparation, remove the breather of the transformer, then connect the vacuum unit to the breather connection port of the transformer, open the bypass valve of the oil pillow, open the valve to be repaired, and close other valves of the transformer; S2, start the vacuum unit, and use the vacuum unit to evacuate the transformer until the vacuum degree of the transformer reaches and remains at the first set value; S3, shut down the vacuum unit and remove the valve to be repaired, remove the connecting bolts between the valve to be repaired and the connecting surface of the valve interface of the transformer, and insert the isolation plate while removing the bolts; S4, the vacuum unit is turned on for the second time to perform vacuum operation. When the vacuum degree reaches the first set value again, the isolation plate is pulled out and the new valve is connected to the valve interface of the transformer; S5, adjust the vacuum unit so that the vacuum degree of the transformer reaches the second set value, and install and tighten the connecting bolts between the valve and the valve interface; S6, stop the vacuum unit and close the bypass valve, slowly break the vacuum until the vacuum is exhausted, disconnect the vacuum unit from the breathing apparatus connection port, and exhaust from the gas relay exhaust port until no gas is discharged; S7, open all valves of the transformer and perform exhaust operation on the transformer; S8, to prevent false oil level, open the oil pillow exhaust valve, inflate the capsule in the oil pillow through the transformer's breather connection port, and stop inflating when no gas is discharged from the oil pillow exhaust port, and close the valve of the oil pillow exhaust port; S9, install the respirator, count the tools, tidy up the site, and take oil samples for testing.

2. The method for oil-treated transformer connection parts according to claim 1, characterized in that: In step S3, the isolation plate includes an isolation plate body and an isolation membrane disposed on the isolation plate body, and the isolation membrane is made of an elastic material.

3. The oil-in-oil maintenance method for transformer connection components according to claim 2 is characterized in that: The isolation plate body comprises an isolation inner plate and an isolation outer plate which are overlapped with each other, and the isolation membrane is fixed between the isolation inner plate and the isolation outer plate.

4. The method for oil-treated transformer connection parts according to claim 3 is characterized in that: The valve interface of the transformer has a flange joint surface, and the diameter of the isolation membrane is larger than the inner diameter of the flange joint surface and smaller than the outer diameter of the flange joint surface.

5. The method for oil-treated transformer connection parts according to claim 1, characterized in that: In step S2, the first set value is 0.8-0.9 kPa.

6. The method for oil-treated transformer connection parts according to claim 1, characterized in that: In step S5, the second set value is a vacuum degree greater than 0.9 kPa.

7. The method for oil-treated transformer connection parts according to claim 1, characterized in that: In step S3, the connecting bolts are removed sequentially from top to bottom, and the isolation plates are inserted synchronously with the removal of the connecting bolts.

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