JPH0799891B2 - Transformer direct-coupled gas-insulated switchgear - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a transformer direct connection type gas insulated switchgear in which a three-phase transformer is configured by using three single-phase transformers. In particular, the present invention relates to a gas-insulated switchgear in which a gas-insulated bus bar is used to form a triangular connection of a transformer.

(Prior Art) When a three-phase transformer is configured with a single-phase transformer, a triangular connection such as a tertiary winding is generally connected to the outside by a cable as the transformer capacity increases. However, in that case, it is required to reduce the number of externally drawn cables.
As one means for satisfying such requirements, each single-phase transformer and the transformer tertiary gas-insulated switchgear connected thereto are connected using a cable as shown in FIG. 4,
Conventionally, there has been proposed a technique for performing a triangular connection on the gas insulated switchgear side.

That is, in FIG. 4, 12a to 12c are single-phase transformers of each phase, and the transformer windings 2 for making a Δ connection are housed therein. Each of the single-phase transformers 12a to 12c is provided with an in-oil cable terminal connecting portion 13, which is connected to the transformer 3
A plurality of cables 14 according to the next capacity are connected, and the cables 14 are connected to the in-gas cable terminal connecting portion 9 provided in the gas-insulated switchgear 15a to 15c of each phase.

The gas-insulated switchgear 15 for each phase consists of the surge arrester 3,
Instrument transformer 4, earthing switch 5, disconnector 6, current transformer 7,
A circuit breaker 8, a current transformer 7, a disconnecting switch 6, and a grounding switch 5 are sequentially provided, and are connected to a power system of each phase by a cable-in-gas terminal connection portion 9 on the tip side thereof.

In such a conventional gas-insulated switchgear, the a-phase single-phase transformer 12a is used for the gas-insulated switchgears 15a and 15b, the b-phase single-phase transformer 12b is used for the gas-insulated switchgears 15b and 15c, and the c-phase is used. By connecting the single-phase transformer 12c to the gas-insulated switchgear 15a and 15c, each single-phase transformer 12a-12c and each gas-insulated switchgear
A triangular connection is formed between the cable end connection portions 9 of 15a to 15c, and the extraction of each phase from this triangular connection is performed on the gas insulated switchgear side. Therefore, in this conventional technique, a phase current flows through each cable 14 instead of a line current, but the phase current Therefore, there is an advantage that the number of cables can be reduced as compared with the case of performing the triangular connection on the single-phase transformer side.

(Problems to be Solved by the Invention) In constructing a three-phase transformer with a single-phase transformer as described above, when a triangular connection such as a tertiary winding is performed outside the transformer using a cable, As shown in FIG. 4, a device for reducing the number of cables has been conventionally made by performing a triangular connection on the gas-insulated switchgear side, but in this conventional technique, a cavern for laying cables is required. At the same time, there is a drawback in that there are many connection points for cable terminals.
Furthermore, when the phase-adjusting equipment connected to the transformer tertiary winding has a large capacity, the transformer tertiary winding capacity also increases, and the number of cables connected in a triangle also increases. In particular, future ultra-high voltage transformers are planned with a capacity of 3000 MVA per bank, and the capacity of the tertiary windings that are connected in a triangle is also very large at 900 MVA, so the number of cables and connecting points will increase. The space required for the cable cavern is also much larger than that of conventional devices.

The present invention has been proposed in order to solve the above-mentioned problems of the prior art, and an object of the present invention is to eliminate the need for a cable tunnel and to directly connect a transformer with a significantly reduced number of connection points. The purpose is to provide a gas-insulated switchgear.

[Structure of Invention]

(Means for Solving the Problems) In order to achieve the above object, the transformer direct connection type gas insulated switchgear of the present invention is a three-phase transformer in which the windings of three single-phase transformers are connected in a triangle. In constructing the above, the constructional feature is that single-phase or three-phase gas-insulated busbars are connected in a triangle outside the transformer.

(Operation) In the present invention having the above-mentioned configuration, by using the gas-insulated bus bar having a much larger capacity than the cable, it is possible to reduce the number of cables for interphase connection and to use this cable. The number of connection points can be significantly reduced as the number of cables is reduced. In addition, the adoption of gas-insulated busbars eliminates the need for caverns that were indispensable for cable connections.

(Embodiment) An embodiment of the present invention will be specifically described below with reference to FIGS. The same members as those in the prior art shown in FIG. 4 are designated by the same reference numerals and the description thereof will be omitted.

FIG. 1 is a connection diagram showing an embodiment of the present invention. In this embodiment, windings 2a to 2c of a single-phase transformer of each phase are connected in a triangle.
Are respectively connected via oil-gas bushings 1 to gas-insulated buses 10a to 10c which connect the phases of the single-phase transformer. Gas-insulated switchgears 15a to 15c for each phase are connected to the intermediate portions of the gas-insulated buses 10a to 10c. Each of the gas-insulated switchgears 15a to 15c has the same structure as that shown in FIG.

An example of the arrangement configuration of each device in the gas insulated switchgear of the present invention shown in such a connection diagram is shown in FIGS. 2 and 3, that is, on the side surfaces of the single-phase transformers 12a to 12c of each phase. Each of the two winding lead-out parts 16 is provided.
Are connected to gas-insulated buses 10a to 10c for interphase connection. Here, the gas-insulated busbars 10a to 10c for connecting each phase are, as shown in FIG. 3 as an example, a gas-insulated busbar 10c for connecting the single-phase transformers 12a and 12c, and another two gas-insulated busbars 10, Ten
It is placed near the base of the gas-insulated switchgear so that it is parallel to b. Each gas-insulated switchgear 15a-15c is connected to the intermediate portion of each gas-insulated busbar 10a-10c.
Connected via 1c. These connecting buses 11a to 11c are
As shown in FIG. 3, the gas-insulated busbars 10a to 10c arranged near the foundation surface are provided in an L-shape from the top, and each gas-insulated switchgear 15a to 15c is provided at the end of the horizontal portion.
Are connected.

In the gas-insulated switchgear of this embodiment having such a configuration, the single-phase transformers 11a to 11c and the gas-insulated switchgear
The connections between 15a-15c are made by gas-insulated busbars, which have a significantly larger capacity than cables. As a result, it is possible to reduce the number of connection points as compared with the cable connection, and to reduce the size and size of the device by eliminating a cavern. Further, in the present invention, the drawing from the triangular connection, which was performed at the gas-insulated switchgear side end of the cable in the conventional device, to each gas-insulated switchgear, in the present invention, can also be performed from a free portion of the gas-insulated bus bar for interphase connection. Therefore, the arrangement of each device constituting the gas insulated busbar and the gas insulated switchgear can be freely set.

(Other Embodiments) The present invention is not limited to the above-described embodiments, and the arrangement of each device constituting the gas-insulated busbar and the gas-insulated switchgear can be freely changed according to the grounding space of the device. It is possible. For example, the gas-insulated busbars 10a to 10c may be arranged not vertically as in FIG. 3 but shifted vertically, or the gas-insulated switchgear may be arranged in parallel with the gas-insulated busbar. it can.

Further, instead of forming each gas-insulated bus bar with a single-phase gas-insulated bus bar as shown in the figure, a three-phase batch type gas-insulated bus bar may be used.

〔The invention's effect〕

As described above, according to the present invention, when the windings of three single-phase transformers are connected in a triangular shape to form a three-phase transformer, the gas-insulated bus bar is used for the interphase connection of each single-phase transformer. It is possible to provide a directly coupled transformer gas-insulated switchgear that can significantly reduce the number of connection points, reduce the size of the entire device, and can cope with future large capacity by simple means. it can.

[Brief description of drawings]

FIG. 1 is a wiring diagram showing an embodiment of a gas insulated switchgear directly connected to a transformer of the present invention, FIG. 2 is a plan view showing an example of the arrangement configuration of the equipment of the gas insulated switchgear of FIG. 1, and FIG. The drawing is a view as seen from the arrow A of FIG. 2, and FIG. 4 is a single wire connection diagram of a conventional device. 1 ... Oil-gas bushing, 2 ... Transformer winding, 3 ... Lightning arrester, 4 ... Instrument transformer, 5 ... Installed switch, 6 ... Disconnector, 7 ... Current transformer, 8 ...... Circuit breaker, 9 ... Gas cable end connection, 10 ... Gas-insulated busbar, 11 ... Connection busbar, 12 ... Single-phase transformer, 13 ... Oil cable end connection, 14 ... Cable , 15 …… Gas insulated switchgear.

Claims (1)

[Claims] 1. A transformer direct connection type gas insulation in which windings of three single-phase transformers are connected in a triangle to form a three-phase transformer, and gas insulation switchgear of each phase is connected to the triangle connection. In the switchgear, pull out the gas-insulated busbars from the single-phase transformers of each phase, connect the gas-insulated busbars to each other to form a triangular connection, and connect the gas-insulated switchgear of each phase to the gas-insulated busbars. A gas-insulated switchgear with a direct connection to the transformer, which is characterized in that