JPS632308A - On-load tap changer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention uses nonflammable gases and liquids as insulators in on-load tap changers, specifically, in switching switches constituting on-load tap changers. This invention relates to an on-load tap changer.

[Conventional technology]

FIG. 2 is a sectional view showing a switching opening/closing portion of a conventional on-load tap changer for a gas insulated transformer, which is disclosed in, for example, Japanese Patent Application Laid-Open No. 56-96819.

As shown in the figure, this type of on-load tap changer has a switching part (2) that transfers the load current from one tap to the other tap, and a tap selection part (2) that performs the function of selecting a desired tap. (not shown) and is housed in the tank (1) of a gas insulated transformer. The switching opening/closing part (2) includes a current-carrying terminal part (3), a switching part (48 current-limiting resistors (5)), and an insulation support (6) for switching on and off the current.
and an energy storage mechanism (7), these are equipped with an insulating cylinder (
8), is housed in a closed container Ql) consisting of a head case (9) and a bottom plate αQ. In order to ensure insulation between ground and ground, SF and gas soda are sealed as nonflammable insulating media in the airtight container space (11a), and fluorocarbon liquid is added to the container to cool the switching opening/closing part (2). Ql
It is poured into an airtight container (b) through a nozzle located on the outside of the container.

Further, FIG. 3 shows a sectional view of a switching opening/closing portion of another conventional on-load tap changer disclosed in, for example, Japanese Unexamined Patent Publication No. 59-1134515. As shown in the figure, in this on-load tap changer, a fluorocarbon liquid μs is sealed as a nonflammable insulating medium in a space of a closed container Q.

[Problem that the invention seeks to solve]

However, in the conventional example shown in FIG. 2, when SF6 gas is used as the nonflammable insulating medium, the insulation performance between ground and the arc extinguishing performance of the changeover switch section (4) is ensured, but SF,
Since it does not function as a lubricant, there is a problem that the mechanical parts are worn out and the durability is poor.

In addition, since the changeover switch section (4) including the current limiting resistor (5) and current-carrying terminal (3) is cooled by pouring the fluorocarbon liquid (2) into the container (2) from the outside, sufficient cooling is not always required. However, in order to suppress heat generation, it was necessary to increase the capacity of the heat generating equipment, especially the current limiting resistor.

Furthermore, the conventional example shown in Fig. 8 uses fluorocarbon liquid (g) as a nonflammable insulating medium and fills the container space (lla) with the fluorocarbon liquid, so it has insulation performance, arc extinguishing performance, lubrication performance, and cooling performance. is obtained, but a large amount of fluorocarbon liquid is required, and as the capacity of the equipment increases, the amount used further increases, so there is a problem that it is not suitable for increasing the capacity from an economic point of view.

This invention was made in order to solve the above-mentioned problems, and is an economical gas insulated transformer that has excellent performance in insulation, arc extinguishing, cooling, lubrication, etc., and is suitable for increasing capacity. The purpose is to obtain a tap changer.

[Means for solving problems]

The switching opening/closing part of the on-load tap changer according to the present invention has a current limiting resistor as a heat generating part, an energizing switch part, and an energizing terminal part arranged so as to be located at the lower part of the sealed container. A nonflammable insulating liquid is filled in an amount sufficient to immerse the heat generating portion, and a nonflammable insulating gas is filled in the upper space of the closed container.

Moreover, the on-load tap changer according to the second aspect of the present invention further includes a pressure fluctuation buffer container whose volume increases or decreases in response to an increase or decrease in pressure in the closed container.

[Effect]

In the on-load tap changer of the present invention, the nonflammable insulating liquid sealed in the lower part of the airtight container cools the current limiting resistor, the energizing switch part, and the energizing terminal part, which generate heat due to energization or switching of the current. The nonflammable insulating gas sealed in the upper space of the sealed container is cooled and condensed by the outside air between the high-voltage changeover switch section, etc., and this condensed liquid is used in the energy storage mechanism and the changeover switch. and other mechanical parts and acts as a lubricant.

〔Example〕

An embodiment of the present invention will be explained below with reference to the drawings. 1st
In the figure, inside the closed container aυ of the switching opening/closing part (2),
From the top, the energy storage mechanism (7), the insulation support, the changeover switch section (4) for switching the current using a vacuum switch or semiconductor switch as the current switching element, and the connection to the tap selector in the current switching element. An energizing switch section (4a) and a current limiting resistor (5), which are connected in parallel with the main arc contact through which the load current always flows, have a lower contact resistance than the main arc contact and through which the load current always flows. It is accommodated. The insulating tube (8) of the sealed container (b) has the above-mentioned energization switch section (4a) and a load current tap selector (not shown).

or a conductive terminal O for leading to a neutral point (not shown)
Q is provided.

The upper part of the space (lla) in the container (b) is filled with SF and H as nonflammable insulating gases, and the lower part is filled with SF6 in which the energizing switch part (4a) and the current limiting resistor (5) are immersed.
Fluorocarbon liquid saturated with gas is sealed as a nonflammable insulating liquid.

In this way, in this embodiment, the conventional changeover switch section (4)
The current limiting resistor (5), which is a heat-generating part and requires cooling, and the current-carrying switch part (4a) are separated.
Since a) is placed at the bottom of the container 0υ, it is possible to soak the heat generating part with a small amount of fluorocarbon liquid.
The heat generating part is effectively cooled.

Furthermore, as mentioned above, since the amount of fluorocarbon liquid egg used is small, the amount of released SF and gas dissolved in the fluorocarbon liquid egg at high temperatures is reduced, and the pressure increase in the closed container (6) is suppressed. .

In addition, the fluorocarbon evaporated by the Joule heat generated in the current limiting resistor (5) and the energizing switch part (4a) wets the mechanical parts such as the changeover switch part (4) and functions as a lubricant. Wear is reduced.

In addition, a vacuum switch or a semiconductor element is used as the current switching element of the changeover switch section (4). In the above embodiment, the changeover switch section (4) is immersed in a fluorocarbon liquid (T), which is a nonflammable insulating liquid. However, when using a semiconductor switch as a diversion switching element, the performance of the semiconductor switch can be maintained at a high level by carefully immersing the changeover switch section (4J) in liquid and cooling it.

Furthermore, by connecting a closed container (a container whose volume changes according to pressure fluctuations), pressure fluctuations in the closed container αυ can be buffered. FIG. 4 is a diagram showing an embodiment of the second invention. Yes, there is a head case that forms a closed container α force t4 (
9) is connected to a pressure fluctuation buffer container aη having a bellows portion and whose volume changes depending on the pressure. In this case, when the pressure inside the container increases due to the heat generated by the heat generating part, the bellows part of the pressure fluctuation buffer container αη expands to increase its volume and suppress the increase in pressure. Further, when the fluorocarbon vapor, SF, or gas is cooled and the pressure decreases, the bellows portion of the pressure fluctuation buffer container 07) contracts to reduce the volume and suppress the decrease in pressure.

〔Effect of the invention〕

As described above, according to the present invention, heat-generating parts such as current limiting resistors are cooled and insulated with a smaller amount of nonflammable insulating liquid than conventional on-load tap changers, and the condensate of the vaporized nonflammable insulating liquid acts as a lubricant for the mechanical parts and reduces wear, making it possible to obtain an economical and reliable tap changer under load that is suitable for upsizing. Furthermore, since pressure fluctuations in the closed container are suppressed by the pressure fluctuation container, the closed container does not require large mechanical strength, so a safer and more economical on-load tap changer can be obtained.

[Brief explanation of drawings]

1 and 2 are cross-sectional views showing the switching opening and closing part of a tap changer for a gas insulated transformer which is an embodiment of the present invention; FIG. 8;
FIG. 4 is a sectional view showing the switching t0 closing portion of a conventional tap changer. In the figure, (1) is the tank of the gas insulated transformer, (2)
(3) is a current-carrying terminal, (4) is a switching switch Rorocarbon liquid, and αη is a pressure fluctuation buffer container. In addition, in the figures, the same reference numerals indicate the same or equivalent parts. Iru Tsujin Oiwa Masuo 1st Figure 1 Nikasu, Temuraen i□, F-R 1t77 Ushio opening/closing sound F3: Electrification''L Netsushi 4: Katana Jou Sui Sochisho 4Q: 〼denmata Iso + livestock p 5: 7a > LKLtn- 12: SF6 Force 15: Fluorocarbon vapor - 2nd Figure 17: 7E7 wheat grain drop 3 Figure 13: Fluorocarbon Figure 4 procedural amendment (spontaneous)

Claims (6)

[Claims] (1) In a tap changer equipped with a tap selection section for selecting a desired tap of a transformer and a switching section for commutating load current from one of the two taps selected by the tap selection section to the other. , the switching opening/closing section is a sealed container, a current limiting resistor is stored and suspended at the bottom of the sealed container, and an energizing switch section that constantly energizes the load current is provided through the lower side wall of the sealed container and is connected to the outside from the energizing switch section. An energizing terminal section that conducts the load current, a changeover switch section that opens and closes the current, an energy storage mechanism that provides high-speed driving force to the changeover switch section, an insulating support that engages the changeover switch section and the energy storage mechanism, and the sealed container. An on-load tap characterized by comprising: the current limiting resistor sealed in the lower part, a nonflammable insulating liquid that soaks the energizing switch part and the energizing terminal part, and a nonflammable insulating gas sealed in the upper space of the sealed container. Switch. (2) In a tap changer equipped with a tap selection section for selecting a desired tap of a transformer and a switching section for commutating load current from one of the two taps selected by the tap selection section to the other. , the switching opening/closing section comprises: a closed container, a current limiting resistor stored and suspended in the lower part of the sealed container, and an energizing switch section that constantly energizes the load current; a current-carrying terminal section that guides the load current to the load current, a changeover switch section that opens and closes the current, an energy storage mechanism that provides high-speed driving force to the changeover switch section, a disconnected wire support that engages the changeover switch section and the energy storage mechanism; The current limiting resistor sealed in the lower part of the sealed container, a nonflammable insulating liquid that immerses the energizing switch part and the energizing terminal part, a nonflammable insulating gas sealed in the upper space of the sealed container, and provided in the sealed container. An on-load tap changer characterized by comprising a pressure fluctuation buffer container whose volume increases or decreases in response to increases or decreases in pressure. (3) The on-load tap changer according to claims 1 and 2, wherein the current switch of the changeover switch section is a vacuum switch. (4) The on-load tap changer according to claims 1 and 2, wherein the current switch of the changeover switch section is a semiconductor switch. (5) the non-flammable wire-breaking liquid is a fluorocarbon liquid;
The on-load tap changer according to claims 1 and 2, wherein the nonflammable insulating gas is SF_6 gas. (6) The on-load tap changer according to claims 1 and 2, wherein the closed container includes a pressure fluctuation buffer container whose volume increases or decreases in response to increases and decreases in pressure.