Structure of pressurized space of oil-filled device, and oil-filled device

Abstract

To provide a structure of a pressurized space of an oil-filled apparatus and the oil-filled apparatus for preventing suction of muddy water in water immersion without causing a trouble in maintenance of a moisture absorption respirator by expanding the pressurized space of the oil-filled apparatus.SOLUTION: A change-over switch 11 of an oil-immersed transformer 200 is housed in a change-over switch chamber 12 of a main body tank 1, and connected to a change-over switch chamber conservator 14 through a change-over switch chamber connecting pipe 13. The conservator 14 is of an open type in which a space filled with the switching device chamber insulating oil 17 and a switching device chamber pressurized space 18 not filled with the insulating oil 17 are not partitioned. The conservator 14 is connected to a change-over switch chamber moisture absorbing respirator 16 through a vent pipe 15, and a spare air chamber 41 is provided in the middle of the vent pipe 15.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a space that is pressurized by volumetric changes in insulating oil in oil-filled equipment, i.e., a structure of a pressurized space from a moisture-absorbing respirator used to prevent deterioration of insulating oil to a conservator, and to an oil-filled equipment equipped with said structure. [Background technology]

[0002] Oil-filled equipment (for example, static equipment such as oil-filled transformers) has an air chamber on top of the oil-filled equipment body or in a dedicated container to absorb volume changes in the insulating oil caused by temperature changes.

[0003] The interior of such an air chamber is called a pressure relief space, and a dedicated container for absorbing volume changes in insulating oil, for example, is called a conservator (see Patent Documents 1 and 2). In addition, tanks and conservators for oil-filled equipment are equipped with moisture-absorbing respirators (see Patent Document 3), which remove moisture from the pressurized space to prevent deterioration of the insulating oil or the rubber diaphragm described below.

[0004] The general device configuration of an oil-immersed transformer 100 (hereinafter referred to as transformer 100) equipped with a conservator will be described with reference to Figure 3. This transformer 100 houses an internal structure 101, i.e., a structure in which a primary coil (N1) and a secondary coil (N2) are wound around a common iron core, in a main tank 1. It is equipped with a main conservator 2 connected to the top of this main tank 1 through a main connecting pipe 3, a main vent pipe 4 extended further above the main conservator 2, and a main moisture absorbing respirator 5 installed at the tip of the main vent pipe 4.

[0005] The main tank 1 is filled with main insulating oil 6, and the main conservator 2 is divided by a rubber diaphragm 8 into a space filled with main insulating oil 6 and a main pressure relief space 7 which is not filled with main insulating oil 6. This rubber diaphragm 8 divider prevents contact between the outside air and the main insulating oil 6, preventing deterioration of the main insulating oil 6 due to oxidation, etc.

[0006] When an on-load tap changer 10 is attached to the transformer 100, the changeover switch 11 is housed in a changeover switch chamber 12 provided in a separate chamber within the main tank 1. In this case, a changeover switch chamber conservator 14 is provided which is connected from the top of the changeover switch chamber 12 through a changeover switch connecting pipe 13, a changeover switch chamber vent pipe 15 is provided which is extended further above the changeover switch chamber conservator 14, and a changeover switch chamber moisture absorbing breather 16 is provided at the tip of the vent pipe 15.

[0007] The conservator 14 has a space filled with changeover switchroom insulating oil 17 and a changeover switchroom pressure relief space 18 that is not filled with the insulating oil 17. However, it is configured as an open-type conservator, and the insulating oil 17 and the pressure relief space 18 are not separated by a rubber diaphragm 8 or the like. This difference is due to the need to release decomposition gases generated during on-load tap changing operations into the atmosphere.

[0008] The amount of expansion and contraction of the insulating oil 6, 17 due to temperature changes is adjusted by the conservators 2, 14. In other words, the insulating oil 6, 17 of the transformer 100 generally becomes hot and expands as the load increases and the outside air temperature rises during the day, and becomes colder and contracts in volume at night as the load decreases and the outside air temperature drops.

[0009] The expansion and contraction of the insulating oil 6, 17 due to temperature rises and falls caused by changes in the outside air temperature and the transformer load changes the oil level in the main tank 1 and the conservators 2, 14 and the volume of the pressure relief spaces 7, 18. This causes the air in the conservators 2, 14 to move in and out of the outside air through the moisture absorbing respirator 5, 16, i.e., breathing occurs.

[0010] The moisture-absorbing respirator 5, 16 will be explained with reference to Figure 4. The moisture-absorbing respirator 5, 16 has a structure in which a respirator 34 is attached below a moisture absorber 31 that contains a moisture-absorbing material 32. The moisture-absorbing material 32 adsorbs moisture from the outside air that flows in through the ventilation holes.

[0011] The moisture absorption performance of the moisture absorbent 32 decreases as the amount of moisture absorbed increases, but silica gel or the like is used, which changes color as it absorbs moisture, making it possible to visually check the degree of moisture absorption. This is because, during monitoring and maintenance, this color change can be confirmed through a viewing window 33 provided on the side of the moisture absorber (container) 31, and the moisture absorbent 32 can be replaced as necessary.

[0012] In addition, in order to prevent the moisture absorbent material 32 stored in the moisture absorber 31 from absorbing moisture unrelated to the original breathing action by constantly being in contact with the atmosphere, a respirator 34 containing partition oil 36 is provided below the moisture absorber 31, so that breathing passes through an oil layer.

[0013] An adsorbent is also placed in this oil layer to remove moisture from the partition oil 36. The operating status of the moisture absorbing breathers 5, 16 is checked from the outside by visually observing the state of bubbles that form in the partition oil 36 placed in a glass oil pan 35. As the partition oil 36 collects dust and other particles floating in the air, the oil may gradually become contaminated. Therefore, during monitoring and maintenance, the oil is checked for contamination and replaced as necessary. In this respect, the moisture absorbing breathers 5, 16 require monitoring of the status of the moisture absorbent 32 and the partition oil 36 and maintenance for replacement. [Prior art documents] [Patent documents]

[0014] [Patent Document 1] Patent Publication No. 2014-53278 [Patent Document 2] Patent Publication No. 2019-145720 [Patent Document 3] Patent Publication No. 2023-82655 Summary of the Invention [Problem to be solved by the invention]

[0015] If the area around the installation site of the transformer 100 is flooded, there is a risk that the transformer 100 will inhale muddy water due to the respiration, as indicated by arrow P in FIG.

[0016] More specifically, before the transformer 100 was submerged, the insulating oils 6 and 17 in the transformer 100 became hot and expanded due to the increase in load and outside temperature. On the other hand, when the area around the transformer 100 became submerged, the transformer 100 was disconnected from the electric circuit, became unloaded, and the submerged water in the surrounding area cooled the insulating oils 6 and 17, gradually lowering their temperature and causing them to contract.

[0017] Such volumetric contraction of the insulating oil 6, 7 causes the oil level in the main tank 1 and the conservators 2, 14 to drop, causing suction through the moisture-absorbing respirator 5, 16. If the suction volume exceeds the air volume in the moisture-absorbing respirator 5, 16, there is a risk that the surrounding muddy water will seep into the conservators 2, 14.

[0018] In this case, the conservator 2 can prevent direct intrusion of muddy water by the rubber partition 8 provided to prevent contact between the outside air and the insulating oil 6.

[0019] However, the conservator 14 is an open type with no partition between the insulating oil 17 and the pressure relief space 18 in order to release decomposition gases generated during operation of the on-load tap changer 10 into the atmosphere.

[0020] As a result, if the suction volume is larger than the volume of the pressurized space leading to the conservator 14, i.e., the combined volume of the ventilation pipe 15 and the breathing apparatus 16, the muddy water will directly mix with the insulating oil 17, and the muddy water with a heavy specific gravity may enter the changeover switch room 12. This will require the replacement of all of the insulating oil 17 in the switch room 12, and in turn the equipment installed in the switch room 12, which may result in a prolonged period of time that the equipment will be unavailable.

[0021] Therefore, it is possible to adopt a measure to install the moisture absorbing respirator 16 at a position higher than the expected flood height, but this may cause problems in monitoring and replacement maintenance of the moisture absorbing material 32 and partition oil 36.

[0022] The present invention has been made to solve these conventional problems, and its problem is to prevent the intake of muddy water when flooded without interfering with the monitoring and maintenance of the hygroscopic respirator. [Means for solving the problem]

[0023] (1) One aspect of the present invention is A structure of a space that is pressurized by a volume change of insulating oil in an oil-filled device, The oil-filled equipment is an equipment container for storing electrical equipment in the insulating oil; a conservator connected to the equipment container via a connecting pipe and configured to adjust a volume change of the insulating oil; a moisture-absorbing respirator that performs a respiration action between the air in the conservator and the outside air; a ventilation pipe between the moisture absorbing respirator and the conservator; Equipped with A sealed spare air chamber is provided in the middle of the ventilation pipe, thereby expanding the space from the moisture absorbing respirator to the conservator.

[0024] (2) Another aspect of the present invention is an equipment container that houses electrical equipment and is filled with insulating oil; a conservator connected to the equipment container via a connecting pipe and configured to adjust a volume change of the insulating oil; a ventilation pipe between the moisture absorbing respirator and the conservator; The oil-filled equipment is configured to include the reserve air chamber. [Effects of the Invention]

[0025] According to the present invention, it is possible to prevent the intake of muddy water during flooding without interfering with the monitoring and maintenance of the moisture-absorbing respirator. [Brief explanation of the drawings]

[0026] [Figure 1]FIG. 1 is a longitudinal sectional view of an oil-immersed transformer to which an embodiment is applied. [Figure 2] FIG. 4 is a longitudinal cross-sectional view showing an example of a spare air chamber. [Figure 3] FIG. 1 is a longitudinal cross-sectional view of a conventional oil-immersed transformer. [Figure 4] A longitudinal cross-sectional view of the same moisture-absorbing respirator. [Figure 5] FIG. 4 is a longitudinal cross-sectional view showing the state of turbid water intake when the area around the installation location of the oil-immersed transformer in FIG. 3 is flooded. DETAILED DESCRIPTION OF THE INVENTION

[0027] The following describes the structure of the pressurized space of an oil-filled device according to an embodiment of the present invention. This structure is applied to stationary equipment such as an oil-filled transformer. In this case, a spare air chamber is provided to expand the space that is pressurized due to volumetric changes in the insulating oil in the oil-filled device, i.e., the pressurized space from the hygroscopic respirator used to prevent deterioration of the insulating oil to the conservator. [Example]

[0028] An embodiment will be described with reference to Figures 1 and 2. Reference numeral 200 in Figure 1 denotes an oil-immersed transformer to which this embodiment is applied. This oil-immersed transformer 200 (hereinafter abbreviated as transformer 200) has a configuration substantially similar to that of the transformer 100 in Figure 1. Here, the same components will be described using the same reference numerals.

[0029] That is, the transformer 200 has an internal structure 101 housed in a main tank 1, i.e., a structure in which a primary coil (N1) and a secondary coil (N2) are wound around a common iron core, and is equipped with a main conservator 2 connected to the top of the main tank 1 through a main connecting pipe 3, a main vent pipe 4 extended further above the main conservator 2, and a main moisture absorbing respirator 5 installed at the tip of the main vent pipe 4, and further has in common with the transformer 100 that the inside of the main conservator 2 is divided by a rubber diaphragm 8 into a space filled with main insulating oil 6 and a main pressure relief space 7.

[0030] It also has an on-load tap changer 10 that changes taps to adjust voltage, a changeover switch 11 as a contact for changing the tap of the changeover device 10, a changeover switch chamber 12 that houses the changeover switch 11, an open-type changeover switch chamber conservator 14 connected from the top of the changeover switch chamber 12 through a changeover switch connecting pipe 13, a changeover switch chamber vent pipe 15 that extends to the top of the conservator 14, and a changeover switch chamber moisture absorbing breather 16 installed at the tip of the vent pipe 15, and further has in common the fact that the conservator 14 is of an open type with no partition between the insulating oil 17 and the pressure relief space 18.

[0031] However, transformer 200 differs from transformer 100 in that a spare air chamber 41 is provided in the middle of the ventilation pipe 15 connecting the conservator 14 and the moisture-absorbing respirator 16. That is, the ventilation pipe 15 has ventilation pipes 15a and 15b, and the upper part of the conservator 14 and the upper part of the spare air chamber 41 are connected by ventilation pipe 15a, and the lower part of the spare air chamber 41 and the upper part of the moisture-absorbing respirator 16 are connected by ventilation pipe 15b. The spare air chamber 41 has an airtight structure so as not to interfere with the breathing action of the moisture-absorbing respirator 16.

[0032] (1) Configuration example of spare air chamber 41 An example of the spare air chamber 41 will be described with reference to Fig. 2. This spare air chamber 41 includes a cylindrical container body 41a with a bottom, and an upper lid 49 that closes the upper opening of the container body 41a.

[0033] The container body 41a has a side wall (peripheral wall) 41b standing on the edge of the bottom wall 41c. The top lid 49 is removably attached to the upper end of the side wall 41b by known means such as screws.

[0034] Furthermore, a connecting pipe seat 43 is attached to the top cover 49, and a connecting pipe seat 42 is attached to the lower part of the side wall 41b. One end of the vent pipe 15a is connected to the connecting pipe seat 43, and one end of the vent pipe 15b is connected to the connecting pipe seat 42. The other end of the vent pipe 15a is connected to the connecting pipe seat 14a attached to the top of the conservator 14, and the other end of the vent pipe 15b is connected to the top of the humidifier 31.

[0035] On the arrow Y side of side wall 41b, monitoring window seat 44 is fixed by means of screws or fastening, and upper and lower cutouts 41e that connect both 41b and 44 are formed, and monitoring windows 46 are fixed above and below cutout 41e of monitoring window seat 44 via gaskets 45. This monitoring window 46 is made of a transparent plate, and there is a gap S between monitoring window seat 44 that connects to each cutout 41e.

[0036] Therefore, when muddy water enters the spare air chamber 41 due to flooding around the installation location of the transformer 200 (hereinafter referred to as flooding of the transformer 200), the amount of water can be confirmed within the range of the monitoring window 46.

[0037] Furthermore, an intake plug 47 for adjusting the air pressure inside the spare air chamber 41 is attached to the top cover 49, and a drain plug 48 for draining water from the spare air chamber 41 is attached to the bottom wall 41c.

[0038] The volume of the spare air chamber 41 is designed to have a sufficient capacity to accommodate the contraction (volume change) of the insulating oil 17 after flooding, taking into consideration that the transformer 200 will stop operating when flooded and that the insulating oil 17 will be cooled and contracted due to the flooding of the surrounding area.

[0039] This allows an appropriate air chamber to be set for the contracted volume of the insulating oil 17. As a result, the volume of the space pressurized by the volume change of the insulating oil 17, i.e., the volume of the pressurized space from the hygroscopic respirator 16 to the conservator 14, is expanded.

[0040] Specifically, the contraction volume of the insulating oil 17 is calculated using equation (1), and the temperature difference in equation (1) is calculated using equation (2). Formula (1): Contraction volume = Amount of insulating oil 17 × Expansion coefficient of insulating oil 17 × Temperature difference Equation (2): Temperature difference = "Temperature of the insulating oil 17 before the transformer 200 is stopped" - "Temperature of the insulating oil 17 after the transformer 200 is submerged" The temperatures of the insulating oil 17 can be determined from past data and used as average values, maximum values, minimum values, etc.

[0041] (2) Example of operation when flooded An example of operation when the surrounding area of ​​the installation location of the transformer 200 is flooded due to heavy rain or the like will be described below. Before the flooding, the insulating oil 17 of the transformer 200 becomes hot and expands due to an increase in load and outside air temperature.

[0042] However, if the area around the installation location of the transformer 200 becomes flooded, the transformer 200 is disconnected from the electric circuit, becomes unloaded, and the insulating oil 17 is cooled by the flooding of the surrounding area, gradually dropping to a lower temperature and contracting.

[0043] As a result, as the oil level in the main tank 1 and the conservator 14 and the volume of the pressure relief space 18 decrease, suction occurs through the moisture absorbing respirator 16. In this case, in the transformer 100, if the suction volume exceeds the air volume in the moisture absorbing respirator 16, surrounding muddy water may enter the conservator 14.

[0044] In contrast, with the transformer 200, by providing a spare air chamber 41 in the middle of the ventilation pipe 15 connecting the moisture-absorbing respirator 16 and the conservator 14, it is possible to make the pressurized space from the moisture-absorbing respirator 16 to the conservator 14 larger.

[0045] That is, it is possible to provide a pressurized space large enough to accommodate the transaction volume due to the contraction volume (volume change) of the insulating oil 17. As a result, as shown by arrow P1 in Fig. 1, if turbid water enters the transformer 200 due to the breathing action of the moisture absorbing respirator 16 when the transformer 200 is submerged, the turbid water will accumulate in the spare air chamber 41, but the turbid water will be prevented from directly entering the conservator 14. In this respect, it is possible to prevent turbid water and foreign matter from entering the insulating oil 17 within the spare air chamber 41.

[0046] In particular, the sealed reserve air chamber 41 is designed with a volume that allows for a margin for the contraction volume (volume change) of the insulating oil 17 when the transformer 200 is submerged and stopped, so that it is possible to effectively prevent muddy water from entering the conservator 14 due to the submersion of the transformer 200, even if the installation position is not at a high place.

[0047] As a result, there is no need to adopt measures to position the hygroscopic respirator 16 above the expected flood height, which prevents the intake of turbid water during flooding without interfering with maintenance of the hygroscopic respirator. Furthermore, according to this embodiment, operation of the transformer 200 can be resumed more quickly after the area around it is flooded. In other words, if turbid water enters the switchgear room 12, it may be necessary to replace all of the insulating oil 17 in the switchgear room 12, and ultimately all of the equipment installed in the switchgear room 12. This would result in a prolonged period during which the transformer 200 would be unavailable. However, according to this embodiment, the intrusion of turbid water during flooding can be avoided, thereby preventing such a situation from occurring.

[0048] Furthermore, although it is necessary to check that the turbid water in the spare air chamber 41 has been discharged when operation is resumed, the amount of turbid water can be checked through the monitoring window 46, which reduces the effort required to check that the water has been discharged and shortens the time required to resume operation.

[0049] At this time, the muddy water remaining in the spare air chamber 41 can be drained directly from the drain plug 48, so that the muddy water can be drained quickly, which also shortens the time until operation can be resumed. In addition, the provision of the air intake plug 47 makes it possible to prevent a decrease in the drainage speed and a decrease in air pressure in the spare air chamber 41.

[0050] Furthermore, there is a risk that mud and other particles that could not be discharged along with the muddy water may remain in the spare air chamber 41. In this case, the removable top cover 49 facilitates cleaning to remove the mud and other particles. Therefore, if mud and other particles are found to have adhered, the time required to remove the mud and other particles before restarting operation can be reduced.

[0051] The present invention is not limited to the above-described embodiment, and can be modified and implemented within the scope of the claims. For example, the present invention can be used not only for the transformer 200, but also for equipment that is oil-filled from the standpoint of insulation and cooling, such as shunt reactors for distribution boards, voltage regulators, and DC reactors, and that are subject to temperature changes. Furthermore, the transformer 200 equipped with this embodiment naturally constitutes the present invention. [Explanation of symbols]

[0052] 1...Main tank (equipment container) 14...Switch room conservator 15(15a, 15b)...Ventilation pipe 16…Switching switch room hygroscopic breathing apparatus 17...Switch chamber insulating oil 41...Auxiliary air chamber 46...Observation window 48...Drain plug (drain part) 49...Top lid 200...Oil-filled transformer (oil-filled equipment)

Claims

1. A structure of a space that is pressurized by a volume change of insulating oil in an oil-filled device, The oil-filled equipment is an equipment container for storing electrical equipment in the insulating oil; a conservator connected to the equipment container via a connecting pipe and configured to adjust a volume change of the insulating oil; a moisture-absorbing respirator that performs a respiration action between the air in the conservator and the outside air; a ventilation pipe between the moisture absorbing respirator and the conservator; Equipped with A sealed spare air chamber is provided in the middle of the ventilation pipe to expand the space from the moisture absorbing respirator to the conservator. A structure of a pressurized space of oil-filled equipment characterized by the above.

2. The ventilation pipe is a first ventilation pipe connecting an upper portion of the reserve air chamber and an upper portion of the conservator; a second ventilation pipe connecting an upper portion of the moisture absorbing respirator and a lower portion of the auxiliary air chamber; Equipped with 2. The structure of the pressurized space of the oil-filled equipment according to claim 1.

3. The volume of the spare air chamber is 2. The structure of the pressurized space of the oil-filled equipment according to claim 1, characterized in that the structure is designed to be larger than the contracted volume of the insulating oil after the immersion of the oil-filled equipment is stopped.

4. The contracted volume is The volume of the insulating oil; the temperature expansion coefficient of the insulating oil; The difference between (the temperature of the insulating oil before the oil-filled equipment is stopped) and (the temperature of the insulating oil after the oil-filled equipment is submerged in water), 4. The structure of the pressurized space of the oil-filled equipment according to claim 3, wherein the structure is determined based on the following:

5. The side of the spare air chamber is provided with: There is a monitoring window that allows the interior to be seen.

2. The structure of the pressurized space of the oil-filled equipment according to claim 1.

6. At the bottom of the spare air chamber:

2. The structure of the pressurized space of the oil-filled equipment according to claim 1, further comprising a drainage section.

7. The upper cover of the air chamber is 2. The structure of the pressurized space of oil-filled equipment according to claim 1, characterized in that it is removable.

8. The conservator: a space filled with the insulating oil; a pressurized space that is not filled with insulating oil; 2. The structure of the pressurized space of the oil-filled equipment according to claim 1, characterized in that it is an open conservator that is not partitioned.

9. an equipment container that houses electrical equipment and is filled with insulating oil; a conservator connected to the equipment container via a connecting pipe and configured to adjust a volume change of the insulating oil; a ventilation pipe between the moisture absorbing respirator and the conservator; The spare air chamber according to any one of claims 1 to 8, An oil-filled device comprising:

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