JPH0618136B2 - Load tap switching device - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a load tap switching device.

[Background of the Invention]

FIG. 4 shows a conventional example of a load tap switching device. As shown in the figure, the load tap switching device is a switching device which is isolated from the tap selector 1 and has an oil tank 3 filled with insulating oil 2 and a breaking portion 4a housed in the oil tank 3. The switch 4 and the oil tank 3 are connected via oil supply and discharge oil pipes 5 and 6, and a live line oil purifier 7 for purifying the insulating oil 2 in the oil tank 3 is provided.

With the load tap switching device thus configured, the oil tank 3 of the switching switch 4 suspended from the inside of the transformer tank 8 and isolated from the tap selector 1 is filled with the insulating oil 2, and the switching is performed therein. The switch 4 and the breaking portion 4a are operated. Therefore, the insulating oil 2 is decomposed by the arc when current is turned on or off, and combustible gas such as hydrogen gas and free carbon are generated. This combustible gas is released by buoyancy into the atmosphere from the gas vent 11 via the conservator pipe 9 and the load tap switching device conservator 10, but the free carbon is insulating oil 2
It floats inside and pollutes the insulating oil 2 and reduces the dielectric strength of the insulating oil 2.

In order to prevent the contamination of this insulating oil 2, the actual development is carried out in Sho-49-75013.
Install the hot-line oil purifier 7 as described in the publication.
The upper part and the bottom part of the oil tank 3 of the switching switch 4 are connected by an oil supply pipe 5 and an oil discharge pipe 6, respectively. When purifying the contaminated insulating oil 2, the insulating oil 2 in the oil tank 3 is circulated through the hot wire purifier 7, and the insulating oil 2 to be purified flows from the bottom to the hot wire purifier 7 through the drain pipe 6. The purified insulating oil 2 flows into the switching switch 4 from above.

By the way, if oil leakage occurs in the oil supply pipes 5 and 6, the pipes in the hot-line oil purifier 7 or the like, that is, the oil purification pipe system of the insulating oil 2 and the oil level is not lowered, generally, it is a controller for a tap switching device under load. A low oil level warning of Beta 10 is issued, but if there is a delay in the arrival of the inspector at the site due to an unmanned substation, or if there is a misfire or missed hearing due to a failure of the low oil level alarm, etc. The delay causes the insulating oil 2 in the oil tank 3 to flow out to the bottom through the drain pipe 6 (Since the switching switch 4 is installed at a position higher than the live wire purifier 7, the insulating oil 2 is made by the siphon system of the piping. Leaks).

As a result, the switch 4 and the breaking portion 4a of the switching switch 4 are exposed to the air, current loss and breaking ability at the time of tap switching are lost, and a short circuit between taps or a ground fault may occur due to an arc, leading to a serious accident. .

[Object of the Invention]

The present invention has been made in view of the above points, and it is possible not only to prevent the insulating oil in the oil tank from decreasing below a certain amount but also to facilitate the replacement of the insulating oil in the oil tank. It is an object of the present invention to provide a tap switching device under load.

[Outline of Invention]

That is, according to the present invention, an oil tank isolated from the tap selector and filled with insulating oil, a switching switch housed in the oil tank, the oil tank and the oil supply / drain pipe are connected to each other, and A hot-line oil purifier for purifying oil, a conservator for a tap switching device at load is provided in the oil tank, and the oil supply pipe is provided on the upper side of the oil tank and the hot-line oil purifier. The oil pipe connects the bottom side of the oil tank and the hot-line oil purifier, respectively, and a part of the oil discharge pipe is piped so as to pass through the upper side in the oil tank. In the tap change device under load, which is provided with an oil level lowering prevention device for preventing the insulating oil in the oil tank from decreasing to a certain amount or less when an oil leak occurs in the oil purifying piping system of the insulating oil, An oil level drop prevention device is installed on a part of the drain pipe airtightly -, A cap that covers the upper part of the cylinder and is airtightly attached to the cylinder, a movable element that is vertically movable in the cylinder, and is provided between the movable element and the cap, and the movable element is A braking spring pressing against the bottom of the cylinder,
A coil wound around the outer wall of the cylinder, an external operation box connected to the coil via a lead wire, the cap and the bottom of the cylinder are provided to penetrate the oil tank and the oil discharge pipe, respectively, and normally, The oil tank and the drain pipe are communicated with each other through the cylinder, and a ventilation hole is formed so that the oil tank and the drain pipe are not communicated with each other when the insulating oil in the oil tank is exchanged. And is designed to achieve the intended purpose.

Example of Invention

Hereinafter, the present invention will be described based on the illustrated embodiments. 1 to 3 show an embodiment of the present invention.
Since the same parts as those of the prior art are designated by the same reference numerals, the description thereof will be omitted. In this embodiment, the insulating oil 2 in the oil tank 3 is prevented from dropping below a certain amount when an oil leak occurs in a part of the oil discharge pipe 6 in the oil tank 3 in the oil purifying piping system of the insulating oil 2. An oil level drop prevention device 12 is provided.

That is, the oil level lowering prevention device 12 is provided on the oil drainage pipe 6a of the A frame portion in FIG. 3 which is a part of the oil level lowering pipe 6 in the oil tank 3. did.
Cylinder 1 airtightly attached to the oil drain pipe 6a of the A frame
3, a cap 14 which covers the upper portion of the cylinder 13 and is airtightly attached to the cylinder 13;
A movable element 15 provided inside the movable element 15, which is movable up and down, and this movable element 1
5 and the cap 14, the mover 15 is provided with an oil drain pipe 6
a braking spring 16 pressed against a, a coil 17 wound around the outer wall of the cylinder 13, an external operation box 19 connected to the coil 17 via a lead wire 18, a cap 14 and the bottom of the cylinder 13, and an oil tank 3, Each of the oil drain pipes 6a is provided so as to penetrate therethrough, and normally, the oil tank 3 is provided via the cylinder 13.
And ventilation holes 20 and 2 that allow the oil drain pipe 6a to communicate with each other.
It consisted of 1 etc. The airtightness between the oil drain pipe 6a and the cylinder 13 is maintained by an O-ring 22 provided therebetween, and the airtightness between the cylinder 13 and the cap 14 is maintained by an O-ring 23 provided therebetween. (Figs. 1 and 2
See figure).

By thus configuring the oil level reduction prevention device 12, the oil level reduction prevention device 12 can prevent the insulating oil 2 in the oil tank 3 from decreasing below a certain amount. That is, when oil leakage occurs in the oil supply pipes 5, 6 and the oil purifying piping system such as the hot oil purifier 7, the insulating oil 2 in the oil tank 3 flows out from the oil exhaust pipe 6 by the siphon method as described above. First, the oil level in the oil tank 3 begins to drop. When this oil level drop reaches the oil drain pipe 6a provided with the oil level drop preventive device 12 of the A frame portion, the air introduced into the oil tank 3 through the conservator pipe 9 is replaced by oil as shown by an arrow in the figure. The oil drain pipe 6 is passed from the ventilation hole 20 of the surface deterioration preventing device 12 through the cylinder 13 and the ventilation hole 21.
It is introduced in a. When air enters the oil drain pipe 6a in this way, the force of sucking the air by the oil drain pipe 6 and the force of sucking the insulating oil 2 from the bottom portion of the oil tank 3 are the ones that suck the air from the bottom portion of the oil tank 3. Since the force of sucking up the oil 2 is smaller than that of the oil 2, the air flows through the drain pipe 6 to prevent the drain pipe 6 from sucking the insulating oil 2 from the bottom of the oil tank 3, and the insulating oil in the oil tank 3 is prevented. 2 is a certain amount or less, that is, the oil drain pipe 6 of the A frame portion provided with the oil level lowering prevention device 12
It can be prevented from falling below the portion a.

In this way, the insulating oil 2 in the oil tank 3, that is, in the switching switch 4
Is prevented from falling below a certain amount, the exposure of the switch switch 4 and the breaking portion 4a to the air is prevented, and the current and breaking ability of the breaking portion 4a are good. Maintained at. In addition, when an abnormality occurs such as a low oil level, for example, an unmanned substation may delay the arrival of the inspector at the site, or a failure or omission due to a failure of the low oil level alarm of the load tap tap switching device conservator 10. Therefore, even if the countermeasure against oil leakage is delayed, the oil level lowering prevention device 12 operates and a certain amount of the insulating oil 2 in the oil tank 3 can be secured, so that an accident can be prevented and the reliability of the product is improved.

Further, when the insulating oil 2 in the oil tank 3 is replaced by using the hot wire oil purifier 7, the following may be done. The coil 17 of the oil level lowering preventive device 12 caps the movable element 15 at the time of energization.
Because it was wound so as to generate an electromagnetic force that pulls up to the side,
The external operation box 19 is operated to energize the coil 17 via the lead wire 18. When the coil 17 is energized in this manner, the mover 15 is pulled up to the cap 14 side of the oil level lowering prevention device 12 and closes the ventilation hole 20 provided in the cap 14. Therefore, when the insulating oil 2 in the oil tank 3 is replaced by the hot-line oil purifier 7, air flows from the vent hole 20 into the oil drain pipe 6a.
Is not introduced into the drain pipe 6 and the insulating oil 2
Thus, the work of exchanging the insulating oil 2 by the hot wire purifier 7 via the oil discharge pipe 6 can be carried out easily and comfortably.

〔The invention's effect〕

As described above, according to the present invention, it is possible to prevent the insulating oil in the oil tank from dropping below a certain amount, and it is possible to easily replace the insulating oil in the oil tank. Can be obtained.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional side view showing a state in which an oil level lowering prevention device is attached to an oil discharge pipe of an embodiment of a load tap switching device of the present invention, and FIG. A plan view, FIG. 3 is a piping diagram of an embodiment of the load tap switching device of the present invention, and FIG. 4 is a piping diagram of a conventional load tap switching device. 1 ... Tap selector, 2 ... Insulating oil, 3 ... Oil tank, 4 ...
… Switching switch, 4a …… Break or break, 5 …… Oil supply pipe, 6,
6a ... Oil discharge pipe, 7 ... Live line oil purifier, 8 ... Transformer tank, 9 ... Conservator piping, 10 ... Load-time tap switching device conservator, 11 ... Gas vent, 12 ...
... Oil level drop prevention device, 13 ... Cylinder, 14 ... Cap, 15 ... Mover, 16 ... Braking spring, 17 ...
Coil, 18 ... Lead wire, 19 ... External operation box, 2
0,21 ... Ventilation holes.

Claims (2)

[Claims] 1. An oil tank isolated from the tap selector and filled with insulating oil, a switching switch housed in the oil tank, and the oil tank connected to the oil tank via a supply / discharge oil pipe. A hot-line grinder for purifying insulating oil is provided, the oil tank is provided with a load-time tap switching device conservator, the oil supply pipe is the upper side of the oil tank and the live-line oil purifier, The oil drain pipe connects the bottom side of the oil tank and the hot-line oil purifier, respectively, and a part of the oil drain pipe is arranged so as to pass through the upper side in the oil tank. In a tap switching device under load, which is provided with an oil level reduction prevention device that prevents the insulating oil in the oil tank from decreasing below a certain amount when an oil leak occurs in the oil purifying piping system of the insulating oil,
The oil level lowering prevention device is a cylinder airtightly attached to a part of the oil drain pipe, and covers the upper part of the cylinder,
Further, a cap airtightly attached to the cylinder, a vertically movable movable element provided in the cylinder, and a braking provided between the movable element and the cap to press the movable element against the bottom of the cylinder. A spring, a coil wound around the outer wall of the cylinder, an external operation box connected to the coil via a lead wire, the cap and the bottom of the cylinder penetrating the oil tank and the oil drain pipe, respectively, and Normally, the oil tank and the drain oil pipe communicate with each other through the inside of the cylinder, and the insulating tank and the drain oil pipe through the cylinder do not communicate with each other when the insulating oil in the oil tank is exchanged. A tap switching device under load, which is characterized in that 2. The tap change under load according to claim 1, wherein the coil is wound so as to generate an electromagnetic force that pulls up the mover toward the cap side when the coil is energized. apparatus.