JPS59189612A - On-load tap-changing transformer - Google Patents

Abstract

PURPOSE:To avoid the malfunction of an oil-flow relay by a method wherein a by-pass pipe is provided between a conservator and a changing switch in order to short-cut a vertical portion of a connection pipe. CONSTITUTION:A by-pass pipe 9a is provided between a conservator 4 and a changing switch 2 in order to short-cut a vertical portion of a connection pipe 5. The by-pass pipe 9a is provided between a part of the horizontal portion of the connection pipe 5 which is placed higher than the part where an oil-flow relay 7 is provided and the conservator 4. With this constitution, the oil-flow relay 7 does not operate when the taps are changed and a transformer whose on-load tap changer is protected from the malfunction of the oil-flow relay 7 can be realized.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an on-load tap changer transformer, and particularly relates to an on-load tap changer (on-load tap changer) that covers a transformer tank, a tap selector, a switching switch, and a gas chamber. This article concerns an on-load tap-changing transformer equipped with a tap-changing device (hereinafter referred to as a tap-changing device).

[Background of the invention]

FIG. 1 shows a conventional example of an on-load tap-changing transformer. Is the on-load tag switching transformer a tag switching transformer as shown in the same figure? Does the tap changer have any tag in a no-current state? It consists of a tap selector 1 for selecting and a switching switch 2 for switching load current, and these are housed together in a separate oil tank that is oil-tight with the transformer body provided on the top of the transformer tag 3. Is it the current of the switching switch 2 when switching the tag normally? This is because the arc caused by the disconnection causes decomposition and deterioration of the oil and scum that accompanies the decomposition and deterioration. The switching switch 2vC is provided with a conservator 4 via five connecting pipes to absorb the amount of oil expansion and contraction caused by oil temperature changes in the switching switch chamber, which is the separate oil tank mentioned above. A gas outlet 6 is provided in the upper part of the conservator 4 for discharging the gas generated during the above-mentioned normal tap switching to the atmosphere. Furthermore, an oil flow relay 7 is connected to the switching switch 2, which is activated by the oil flow caused by the increase in internal pressure due to an internal abnormality and detects any internal abnormalities.
The head of the switching switch 2 and the vertical part of the connecting pipe 5 are connected by a bypass pipe 9 via a check valve 8.

In the tag switching device configured in this way, the check valve 8 is normally in an open state, and the gas generated by tag switching passes through nine bypass pipes and is discharged into the atmosphere from the gas outlet 6. When an internal abnormality occurs, the opening is closed due to the increase in internal pressure, and an oil flow is generated toward the side of the connecting pipe 5 provided with the oil flow connecting device 7. However, with such a tap changer, there is a risk that the changeover switch chamber may be damaged due to a sudden increase in internal pressure that occurs when an internal abnormality occurs in the changeover switch 2. It was necessary to open the head cover and lift it out for inspection, but each time it was necessary to remove the cross tube 9. ,.

In order to prevent such problems, a tap changer assembly was constructed by providing ten gas chambers in the head of the changeover switch 2, as shown in FIG. By doing this, the sudden increase in internal pressure that occurs when there is an internal abnormality in the switching switch 2 can be alleviated in the gas chamber 10, and damage to the switching switch chamber can be prevented. Also, since there is no bypass pipe installed when inspecting the inside of the switching switch 2, there is no need to remove it by 7%. Now you can do it easily. However, such tag switching devices have the following drawbacks.

That is, when a tap changer performs a normal tap change, a certain amount of gas is released through the connecting pipe 5 due to the effects of the gas generated by the tap change and gas expansion due to the rise in oil temperature in the gas chamber 10. A phenomenon occurs, but when this gas passes through the vertical part of the connecting pipe 5, it forms a gas column in the vertical part as shown in the figure. As a result, the pressure inside the gas chamber 10 is reduced by the static pressure due to the oil head corresponding to this gas column. As a result, the gas in the gas chamber 10 expands and is forced into the connecting pipe 5, creating a large oil flow inside the connecting pipe 5, which in turn causes the oil flow relay 7 to operate. In other words, it will malfunction.

[Purpose of the invention]

The present invention has been made in view of the above points, and is an on-load tap changer that makes it possible to prevent malfunctions of oil flow relays. To provide an on-load tap changing transformer with? This is the purpose.

[Summary of the invention]

That is, the present invention is characterized in that a bypass pipe for short-circuiting the vertical portion of the connecting pipe is entirely provided between the conservator and the switching switch.

[Embodiments of the invention]

The present invention will be explained below based on the illustrated embodiments. FIG. 3 shows an embodiment of the invention. It should be noted that the same parts as in the prior art are given the same reference numerals, so their explanation will be omitted. In this embodiment, a bypass pipe 9a' is provided between the conservator 4 and the switching switch 2 to short-circuit the vertical portion of the connecting pipe 5.

Then, in the horizontal part of the connecting pipe 5 between the switching switch 2 and the conservator 4, the horizontal part on the switching switch 2 side that is higher than the part where the oil flow relay 7 is installed is connected to the binoculars pipe 9a'. and conservator 4. By doing so, the oil flow relay 7 does not operate when the tap is changed, and the tag changer at the time of load can prevent the oil flow relay 7 from malfunctioning. An on-load tamp switching transformer can be obtained with.

In other words, since the horizontal part of the connecting pipe 5 on the switching switch 2 side, which is higher than the part where the oil flow relay 7 is attached, and the conservator 4 are connected by the bypass pipe 9a, normal tap switching is not possible. The gas generated during the operation passes from the switching switch 2 to the bypass pipe 9a' via the check valve 8, reaches the conservator 4, and is released into the atmosphere from the gas outlet 6. Even if a large amount of gas passes through the bypass pipe 9ai and forms a scum column in the bypass pipe 9a, static pressure due to a constant head is always applied to the gas chamber 10 from the vertical portion of the connecting pipe 5. Therefore, the pressure inside the gas chamber 10 can be maintained at a constant level. Therefore, the gas in the gas chamber 10 does not expand due to the pressure drop in the gas chamber 10 as in the conventional case, and a large oil flow due to the expanding gas does not occur in the connecting pipe 5. 'The turtle device 7 no longer operates or malfunctions.

Another embodiment of the invention is shown in FIG.

In this embodiment, the bypass pipe 9b is located between the horizontal part between the oil relay 7 and the conservator 4, and between the horizontal part of the oil relay 7 side from the conservator 4 side and the conservator 4. Established. By doing this, the pressure inside the gas chamber 10 during normal tamp switching is kept constant by the vertical portion of the connecting pipe 5, and the same effect as in the case described above can be achieved. can.

〔Effect of the invention〕

As mentioned above, the present invention maintains the pressure in the gas chamber constant when changing the tap, so it is maintained at the - foot, preventing a large oil flow from occurring in the connecting pipe, and reducing the oil pressure. It is possible to obtain an on-load tap changer transformer having an on-load tap changer that can prevent malfunctions of current relays.

[Brief explanation of drawings]

FIG. 1 is a vertical side view of the area around the tap changer of a conventional negative tap changeover transformer, and FIG. 2 is a vertical side view of the tap changer bend of another example of a conventional tongue changeover transformer under load. FIG. 3 is a longitudinal sectional side view of the surrounding tap changer of one embodiment of the on-load tap-changing transformer of the present invention, and FIG. 4 is a tap changer of another embodiment of the on-load tap-changing transformer of the present invention. It is a vertical side view of an enclosure.

Claims (1)

[Claims] 1. A tamp selector and a switching switch on the transformer tank. In an on-load tap-changing transformer that has a gas chamber part and is equipped with an on-load tap changer and connects a conservator with a connecting pipe in which an oil flow relay is interposed in the gas chamber, between the conservator and the switching switch. Bypass pipe to short-circuit the vertical part of the connecting pipe? A tamp switching transformer with all the features provided. 2. The bypass pipe is a horizontal part of the connecting pipe between the switching switch and the conservator, and a horizontal part on the switching switch side that is higher than the part where the oil flow relay is attached. The on-load tag switching transformer according to claim 1, which is provided between the transformer and the conservator. 3. The bypass pipe is a horizontal portion between the oil flow relay and the conservator, and is located between the horizontal portion on the oil flow relay side that is higher than the conservator side and the conservator. An on-load tap-changing transformer according to claim 1, wherein the on-load tap-changing transformer is provided.