JPH02123715A - Gas-insulated on-load tap changing transformer - Google Patents

Abstract

PURPOSE:To prevent the shortening of the life of a vaccum valve and to provide a transformer having a highly reliable rotary sealing part by housing a switch into a switch chamber which is separated from a transformer main body includ ing a tap selector, and providing a structure wherein high pressure is not loaded on the switch itself. CONSTITUTION:High pressure insulating gas 5a is sealed in a tank 6b of a transformer main body 110. A main body 4 of the center of the transformer and a tap selector 3 of an on-load tap changer are housed in the main body 110. Low pressure insulating gas 5b is sealed in a switch chamber 120. A switch 1 of the on-load tap changer is housed in the chamber. The tank 6b of the transformer and the switch chamber 120 are separated with an insulating barrier 130 in an airtight manner. When the switch 1 and the tap selector 3 are separat ed in this way, the pressure of the insulating gas on the side of the switch 1 can be made low. In this constitution, the life of a vaccum valve which opens and closes the current in the switch can be made long. There is no difference between the inner and outer pressures at the sealing part. The number of shaft rotations can be made small, and sealing performance can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a gas-insulated load tap-change transformer insulated with SF, gas, or the like.

(Prior Art) Transformers installed in densely populated areas such as large cities have replaced conventional oil-immersed transformers with nonflammable gas-insulated transformers that do not cause fires. Furthermore, despite the large power consumption in large cities, restrictions on the installation space for power equipment require relatively small equipment with large capacity. Therefore, in the case of a gas insulated transformer, it is an absolute requirement to fill in an insulating gas at high pressure in order to reduce the internal insulation distance.

A vacuum valve large load tap changer is attached to the gas insulated transformer, and the structure of a conventional gas insulated load tap changer will now be described with reference to FIG.

In Figure 2, 10 is an on-load tap changer and a transformer 60.
It is suspended from a cover 68 of the tank 6b that forms the outer circumference of the tank 6b, and is housed inside the tank 6b. 5 is insulating gas,
4 is the main body of the transformer, and its main components are an iron core 4a and a coil 4b wound around the iron core 4a.

The on-load tap changer IO is composed of a changeover switch 1 that switches on and off the current, and a tap selector 3 that does not switch on and off the current.

Furthermore, the current switching of the switching switch 1 is performed by a vacuum valve 2. The on-load tap changer 10 is driven by the tank 6b.
This is done by transmitting the rotational force generated by the electric operating mechanism 9 attached to the outside of the switch to the switching switch 1 and the tap selector 3 via the transmission shaft 8. Since there is a pressure difference between the insulating gas 5 and the atmosphere outside the transformer, the on-load tap changer 10 is provided with a rotary seal portion 71 and a static pressure seal portion 72.

The switching switch 1 and the tap selector 3 are electrically connected, and the tap selector 3 is further electrically connected to the transformer coil 4b.

(1) Problems to be Solved by the Invention The conventional gas-insulated load tap changer transformer described above has the following problems.

In the transformer body 60, a high pressure insulating gas 5 is sealed in a tank 6b to reduce the insulation distance. Accordingly, the on-load tap changer 10 itself is placed under high pressure.

In this case, the vacuum valve 2 attached to the switching switch 1 receives a considerably high pressure from the outside compared to the vacuum inside the valve, and the life of the bellows 21, which is a sealing part for external pressure, is significantly reduced. This controls the lifespan of the vacuum valve 2 itself, and significantly reduces the electrical lifespan of the on-load tap changer 10.

Next, since the rotary seal portion 71 is similarly placed under a high pressure difference with the outside air, the one-rotation seal portion 71 is required to have high reliability. Furthermore, if the sealing of this rotary seal section 71 is broken, the entire insulating gas 5 inside the transformer may be released, causing a major accident, so it is not preferable to seal this section with a single layer. .

The present invention was proposed in order to solve the problems of the prior art described above, and its purpose is to provide a structure in which the switching switch itself is not subjected to high pressure.

It is an object of the present invention to provide a gas-insulated load tap change transformer having a structure with a rotary seal part that prevents the life of a vacuum valve from decreasing and has high reliability.

[Structure of the invention]

(Means and effects for solving the problem) In order to achieve the above object, the present invention stores the switching switch in a switching switch room separated from the transformer main body including the tap selector, and The pressure of the insulating gas sealed inside the room is lower than that of the transformer itself. Furthermore, the rotary seal portion improves sealing performance by adjusting the shaft rotation speed in relation to the sealing pressure. In addition, the double-rotation seal structure eliminates the pressure difference between the inside and outside of the final stage seal, and the shaft rotation speed is adjusted to a smaller value to improve sealing performance.

(Example) An embodiment of the present invention will be described below with reference to the drawings.

Note that parts that are the same as those in the conventional configuration are designated by the same reference numerals, and a description thereof will be omitted.

In FIG. 1, 110 is the main body of the transformer, and the tank 6b
A high pressure insulating gas 5a is sealed inside.

Similarly, the tank 6b houses the main body of the transformer and the tap selector 3 of the on-load tap changer. 12
Reference numeral 0 denotes a switching switch chamber, which is filled with a low-pressure insulating gas 5b, and houses a switching switch 1 of a load tap changer. The transformer tank 6b and the switching switch chamber 120 are completely separated in an airtight manner by an insulating barrier 130.

The rotational driving force from the electric actuator 4t9 is transmitted to the transmission shaft 8 and decelerated by the first reduction gear mechanism 73, and then the switching switch 1
is transmitted to. Further, the rotational driving force decelerated by the first reduction gear mechanism 73 is transmitted to the intermediate rotation transmission shaft 11 placed between the switching switch 1 and the tap selector 3, and is further decelerated by the second reduction gear mechanism 74 to tap the tap selector. It is transmitted to the selector 3.

The first and second reduction gear mechanisms 73 and 74 are housed in gear nodes 22 and 32, respectively, and the pressure seal from the outside of the transformer is provided with a rotary seal 71a as a first stage, and a switching switch 1 and a rotary seal 71a as a second stage. A rotary seal 71b is provided on the shaft portion inserted into the tap selector 3.

Further, the pressure in the switching switch side gear box 22 is made to match the pressure of the insulating gas 5b in the switching switch chamber 120, and the pressure in the negative tab selector side gear box 32 is adjusted to match the pressure of the insulating gas 5a in the transformer tank 6b. is matched with the pressure of

Regarding insulation in the case of on-load tap changers, changeover switches require insulation only between adjacent taps.

On the other hand, a tab selector has a characteristic unique to on-load tap changers in that it requires insulation between all taps.

Therefore, if the switching switch 1 and the tap selector 3 are separated as described above, the insulating gas pressure on the switching switch 1 side can be lowered. Therefore, according to the configuration of the present invention, the switching switch 1
The pressure applied to the vacuum valve 2 is considerably lower than in conventional configurations. Therefore, the life of the bellows 21 that seals the vacuum valve 2 is longer than that of the conventional configuration. In other words, the electrical life of the under-load tap changer mortar is extended.

Furthermore, by adopting a configuration in which the switching switch 1 and the tap selector 3 are separated as in the present invention, the rotation speed R1 of the rotating shaft input to the switching switch chamber 120 and the rotation speed R8 input to the tap selector 3 can be set arbitrarily. It can be adjusted to

In other words, the first gear box 22 on the switching switch side which is the low pressure side
The shaft rotation speed R1 of the stage rotary seal 71a section is assumed to be the same as the conventional rotation speed, and the first stage rotary seal of the tap selector side gear box 32, which is the high pressure side? The shaft rotation speed R4 of the la section can be reduced.

Since the rotary sealing performance is controlled by the sealing pressure and the shaft rotational speed, even if the tap selector 3 side is held at a high pressure, the rotational speed of the seal portion is lower than that of the conventional device, so the sealing performance is improved compared to the conventional device.

In addition, since the sealing pressure of the rotary seal portion on the switching switch 1 side is lower than that of the conventional device, the sealing performance is also improved compared to the conventional device. Stage rotating sticker?
The shaft rotation speed is lower than that of the la section, and is among the second stage rotary seals 71b.

Since there is no pressure difference on the outside, the sealing performance is even better than that of the first stage rotary seal.

When adopting a double rotating seal structure like this, the duty of the first stage rotary seal is more severe than the duty of the second stage rotary seal, so if a problem occurs with the seal, the duty of the rotary seal on the first stage side is more severe. It will become. Even in this case, the insulating gases 5b and 5a sealed in the switching switch chamber 120 and the transformer tank 6b continue to be sealed by the second stage rotary seal 71b. Furthermore, even in such a heavy seal state, the shaft rotation speed of the second stage rotary seal 71b is smaller than that of the conventionally configured rotary seal, and in addition, the switching switch chamber 120
The pressure is lower than before, and on the other hand, the high-pressure seal part on the tab selector 3 side has a very low rotation speed, so even in the event of a failure, the sealing performance will be better than the double seal of the conventional structure. . If there is a sealing failure in the first-stage rotary seal 71a, if pressure gauges are provided in the gear boxes 22 and 32, the failure can be detected before the failure extends to the second-stage rotary seal 71b.

〔Effect of the invention〕

As explained above, according to the present invention, the switching switch chamber and the transformer main body are configured separately, so that the pressure of the insulating gas sealed in the switching switch chamber can be lowered, and as a result, the switching switch current It is possible to provide a gas-insulated on-load tap changer transformer in which the vacuum valve that opens and closes can have a long life, and the electrical life of the on-load tap changer is extended.

Furthermore, with the separation configuration of the present invention, the shaft rotation speed of the rotary seal part of the tap selector, which is the high pressure side, is reduced, and the rotary seal part on the switching switch side, which has the same shaft rotation speed as the conventional one, is made to have a low pressure. This improves the performance of the rotary seal, and since the rotary seal has a double seal structure via a reduction gear, there is no pressure difference between the inside and outside of the part that ultimately seals the switching switch and the transformer body. The shaft rotation speed can be reduced without
It is possible to provide a gas-insulated load tap changer transformer with improved sealing performance.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a gas insulated load tap changer transformer according to the present invention, and FIG. 2 is a block diagram of a conventional gas load tap change transformer. 1...Switching switch 2...Vacuum valve 3...
・Tap selector 4...Transformer contents body 5a...
・Transformer main body side insulating gas (high pressure) 5b... Switching switch room side insulating gas 8... Rotating transmission shaft 11... Intermediate rotating transmission shaft 10... On-load tap changer 22... Switching switch side gear node 32...Tap selector side gear box 71a...First stage rotary seal 71b...Second stage rotary seal 73...First reduction gear mechanism 74...Second reduction Gear mechanism 110...Transformer body 120...Switching switch chamber 130...Insulation barrier agent Patent attorney Noriyuki Chika

Claims (1)

[Claims] (1) A tap selector that switches the tap when the voltage transformer is loaded, a transformer tank that houses the contents of the transformer and seals insulating gas inside, and a switch that is isolated and sealed from the transformer tank and stores insulating gas inside. A switch chamber, a switch switch having a vacuum valve housed in the switch chamber, an electric operation mechanism provided outside the transformer tank for driving the tap selector and the switch switch, and the electric operation A conduction shaft that transmits rotational force from the mechanism to a tap selector and a switching switch, the transmission shaft passing through the transformer tank and making the gas pressure in the switching switch chamber lower than the gas pressure in the transformer tank. The rotational speed of the shaft is smaller than the shaft rotational speed of the transmission shaft that passes through the switching switch chamber, and the rotary seal portion where the transmission shaft passes through the transformer tank and the switching switch chamber has a double seal structure. Tap-changing transformer with gas insulated load. 2. The gas-insulated load tap change transformer according to claim 1, which has a double seal structure and is configured to eliminate pressure difference between the inner and outer sides of the second stage rotary seal portion.