JPH0353765B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention provides an oil leakage prevention device that prevents oil from leaking from the joint of an oil-filled electrical appliance, particularly an oil-filled electrical appliance in which the upper and lower parts of the main tank are joined by flanges. Regarding the attached oil-filled appliances.

In an oil-filled electrical appliance, such as an oil-filled transformer, a transformer main body 4 is housed in a main body tank 2, as shown in FIG. 1, and the tank 2 is filled with insulating oil and the transformer main body is immersed therein.
In this case, the main tank 2 is generally an upper tank 2a.
and the lower tank 2b, and the connecting part is the flange 2 of the upper tank 2a, as shown in FIG.
c and the flange 2d of the lower tank 2b are placed opposite each other, an oil-resistant gasket 4 is interposed between the two flanges, and the bolt 5 is tightened to form a joint that prevents leakage of insulating oil, as shown in Fig. 1. A conservator 6 is provided above the main body tank 2 and connected to the main body tank 2 by a pipe 7 forming an oil passage. Note that the main body tank 2 is provided with bushings 8 and 9.

In an oil-immersed transformer having such a structure, the highest oil level is within the conservator 6, so oil pressure is always applied to the inner peripheral surface of the packing 4, and the insulating oil 3 is likely to leak to the outside. Therefore, when oil leakage from this part is discovered, immediately tighten the bolt 5 or apply adhesive to the ends of both flanges 2c and 2d or the bolt 5 to form an oil-proof film. If this does not stop the oil leakage, the operation of the oil-immersed transformer is stopped, the flanges 2c and 2d to which the insulating oil 3 is attached are cleaned, and the gasket 4 is replaced. In order to replace the gasket 4, it is necessary to remove the upper tank 2a, which makes the repair very large-scale.Also, even if the oil-immersed transformer is prevented from operating and the gasket 4 is replaced, a new gasket cannot be used. Hydraulic pressure was applied to No. 4 as well, and there was no change in the fact that it was still susceptible to oil leakage, and concerns about oil leakage could not be eliminated.

In view of the above-mentioned situation, this invention prevents oil leakage by balancing the hydraulic pressure applied to the packing of the flange joint with atmospheric pressure.

The present invention will be explained below based on embodiments shown in the drawings. In FIG. 3, the main body tank 2 housing the transformer main body 1 is composed of an upper tank 2a and a lower tank 2b, which are integrally formed by a flange joint 2E. The details of the flange joint are the same as in FIG. Further, a conservator 6 is provided at the upper part of the main body tank 2 and is connected to the main body tank 2 through a pipe 7, and the insulating oil 3 is contained in the air chamber 6-A leaving an air chamber 6-A on the upper surface.

A control tank 10 is provided beside the main body tank 2 to control the air pressure applied to the insulating oil filled in the main body tank and the pressure of the insulating oil itself. They are connected by a pipe 12.

This control tank 10 is provided with an oil level gauge 11, and this oil level gauge is connected to the flange joint part 2 of the main tank.
The height approximately equal to the height of E is set as the reference oil level L ₀ ,
The position _L1, which is somewhat higher than this standard oil level, and the position _L2 , which is somewhat lower, are defined as the upper control oil level and the lower control oil level, respectively, and when these control oil levels are reached, the contact operates, and the conservator The pressure of the insulating oil at the flange connection portion is made approximately equal to atmospheric pressure by discharging or suctioning the air in the flange 6 by a mechanism to be described later.

The upper part of the control tank 10 is connected to the control breather 13 through a pipe 14.
The air above the insulating oil inside can be increased or decreased depending on the amount of oil inside.

Moreover, on the upper surface of the conservator 6, two pipes 15 to 15 communicate with the air chamber 6-A.
6 and 17, one pipe 16 is connected to a conservator breather 20 via a solenoid valve 18 that operates at a low oil level _L2 , and the other pipe 17 is connected to a conservator breather 20 when the oil level is low. It is connected to a vacuum pump 21 via a solenoid valve 19 that operates at a high oil level of _L1 . Note that dotted lines in the figures indicate electrical connections. In such a structure, the contact point of the oil level gauge 11 operates when the oil level rises to L ₁ or decreases to L ₂ .

For example, when the oil level reaches L ₁ (upper control oil level), the contact turns ON, the solenoid valve 19 opens, the vacuum pump 21 operates, and the conservator 6
Air is discharged from the air chamber 6A to create a negative pressure.
Also, when the oil level reaches L ₂ (lower control oil level), the contact turns ON and the solenoid valve 18 opens to suck air from the conservator breather 20 and fill the air chamber 6A of the conservator 6. Inhale air and pressurize it.

To explain the state of the insulating oil in the oil-immersed transformer of this invention, both the main body tank 2 that houses the transformer body and the control tank 10 are filled with insulating oil 3, and the highest oil level is lower than that of the conventional one. Since it is located inside the conservator like an oil-immersed transformer, oil pressure is applied to the gasket 4, making it easy for insulating oil to leak to the outside. At this time, the oil pressure gauge 11 of the control tank indicates the upper management oil level.
Indicate L ₁ . Then, when the power supply for the electromagnetic valves 18, 19 and the vacuum pump 21 and the control power for the oil level gauge are turned on, the contact point of the oil level gauge _L1 turns on (ON), the electromagnetic valve 19 opens, and the vacuum pump 21 operates. . By the operation of the vacuum pump 21, the air in the conservator 6 is exhausted to the outside, the oil level in the control tank 10 is pushed down to the reference oil level _L0 , and the hydraulic pressure applied to the gasket 4 of the main body tank 2 is reduced. and equilibrates with atmospheric pressure. Due to this drop in the oil level, the contact at the upper management oil level _L1 of the oil level gauge 11 is turned OFF, the solenoid valve 19 is closed, and the operation of the vacuum pump 15 is stopped.

The oil-immersed transformer is operated in a state in which the oil pressure and atmospheric pressure at the gasket 4 maintain an equilibrium relationship, that is, in a state in which oil leakage is less likely to occur. In this case, the inside of the air chamber 6A of the conservator 6 is at negative pressure.

Next, when the oil temperature rises as the outside temperature rises, the equilibrium state between the oil pressure at the gasket 4 and the atmospheric pressure is disrupted, but the oil level in the control tank 10 rises, causing the oil level to rise from _L0 to _L1. When this happens, the equilibrium state can be restored by operating the vacuum pump 15.

When the oil-immersed transformer stops operating and the oil temperature drops,
The equilibrium state between the oil pressure and atmospheric pressure at the gasket 4 is disrupted, but since the air chamber of the conservator 6 has negative pressure, the oil level in the control tank 10 drops and the oil level gauge changes from _L0 to _L2 . Then, the contact point of the lower management oil level _L2 of the oil level gauge 11 is turned ON, the electromagnetic valve 18 is opened, and air is sucked from the conservator breather 20 toward the conservator 6. As a result, the oil level in the control tank 10 is pushed up to the reference oil level _L0 , and the oil level at the bottom of the oil level gauge 11 is
Turn off the contact of _L2 and turn off the solenoid valve 18.
is closed, and the equilibrium state between the oil pressure and atmospheric pressure at the gasket 4 is restored.

As described above, according to the present invention, the oil level gauge 11 of the control tank 10 detects oil level fluctuations, and when the oil level rises and reaches the upper control oil level _L1 , the vacuum pump 21 is activated. , the oil level is lowered to the reference oil level L ₀ , and when the oil level drops and reaches the lower control oil level L ₂ , the conservator breather 20 operates to suck air into the conservator and lower it to the reference oil level L ₀ . The oil level rises, thereby making it possible to always maintain the oil pressure at the gasket 4 in equilibrium with the atmospheric pressure and to prevent oil leakage from occurring at the gasket 4 at the flange joint.

Therefore, once the reference oil level L ₀ is determined, it is possible to automatically and efficiently prevent oil leakage by setting the upper management oil level and the lower management oil level to appropriate widths.

In addition, in the above explanation, the flange part was explained as the flange part 2E of the upper tank 2a and the lower tank 2b, but even if it is a flange part where leakage can occur, such as a flange part of a bushing adapter or a flange part of an elephant chamber, for example. good.

[Brief explanation of drawings]

Fig. 1 is a simplified front view showing an example of a conventional oil-immersed transformer; Fig. 2 is an enlarged partial vertical sectional view of the flange portion of the oil-immersed transformer shown in Fig. 1; and Fig. 3 is an oil-immersed transformer according to the present invention. FIG. 2 is a simplified front view showing the structure of the container. 1: Transformer main body, 2: Main tank, 2a: Upper tank, 2b: Lower tank, 2c, 2d: Flange, 2E: Flange part, 3: Insulating oil, 4: Packing, 5: Bolt, 6: Conservator, 6A: Conservator air chamber, 7, 12, 14, 15, 16,
17: Pipe, 8, 9: Bushing, 10: Control tank, 11: Oil level gauge, 13: Control breather, 18, 19: Solenoid valve, 20: Conservator breather, 21: Vacuum pump, L ₀ : Reference oil level, L ₁ : Upper control oil level, L ₂ : Lower control oil level.

Claims (1)

[Claims] 1 In an oil-filled electrical appliance, the upper and lower parts of the main tank housing the oil-filled electrical appliance are joined by a flange, a conservator is provided above the main tank, and the main tank is communicated with the main tank. An insulated oil control tank is provided outside the main body with an oil level gauge that sets the upper control oil level and lower control oil level, with the flange joint surface as the reference oil level, and the lower part of the control tank is connected to the lower part of the main tank. The upper part of the control tank is connected to the breather for the control tank by a pipe, and the air chamber of the conservator and the vacuum pump are connected through a solenoid valve opened at the upper control oil level of the oil level gauge, and the other One is to connect the conservator breather with a pipe through a solenoid valve that opens at the lower control oil level of the oil level gauge, and open and close the oil level gauge contacts depending on the rise and fall of the oil level in the control tank. An oil-filled electric appliance equipped with an oil leak prevention device, characterized in that the oil pressure in the main body tank is automatically balanced to atmospheric pressure by opening and closing a solenoid valve to increase or decrease the air in the air chamber of the conservator. .