JPH0246110A - Enclosed switchboard for power generation main circuit - Google Patents

Abstract

PURPOSE:To facilitate design of arrangement by connecting a switchboard encapsulating insulation gas with a phase separation bus connecting between a generator and a main transformer and supporting the switchboard only through the phase separation bus. CONSTITUTION:An enclosed switchboard 6A is enclosed air-tightly by an outer sheath 19A and a flange 18A, where a flange 20 is formed on the outer sheath 19A. The enclosed switchboard 6A is supported directly by a phase separation bus 4 when the flange 20 and a flange 21 at the side of a branch sheath 4E' are tightened through bolts and the like. The outer sheath 19A and the flange 18A are ground through the tightening. A pair of transformers 7 are contained in the enclosed switchboard 6A and connected through a connecting conductor 15A with a bushing 12. SF6 gas is encapsulated, as insulation gas, in the enclosed switchboard 6A with pressure of about 0.5kg/cm<2>. Consequently, the volume is reduced by a factor of 10 and the weight is also reduced considerably.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a closed switchboard connected to a power generation main circuit composed of a generator, a main transformer, a phase-separated bus, and the like.

[Prior Art] FIG. 3 is a plan view showing the equipment arrangement of a power generation main circuit including a conventional closed switchboard for the power generation main circuit, as disclosed in, for example, Japanese Utility Model Application Publication No. 51-107635. Figure 4 is the IV of Figure 3.
- It is a figure seen from the IV line. FIG. 5 is a single line diagram of the power generation main circuit shown in FIGS. 3 and 4. FIG. In each of the above figures, the generator (1), circuit breaker (5), and main transformer (
2) are connected to each other by a phase separation bus (4) to form a main power generation circuit. A circuit breaker (5) is provided to open and close this power generation main circuit, and a station transformer (3) is connected between the circuit breaker (5) and the main transformer (2) via a phase-separated bus (4). connected. Each closed switchboard (6a)
, (6b) and (6c) are phase separation busbars (4a
, 4b and 4c) and are commonly referred to as PT closed switchboard, 1'T-SA closed switchboard and NCR closed switchboard, respectively. The PT-closed switchboard (6a) includes voltage detection transformers (7, 7), etc.
The SA closed switchboard (6b) has a transformer (7a) and a lightning arrester (8).
) and surge absorption capacitor (9), etc., the NCR closed switchboard has built-in neutral point grounding transformer (10), resistor (11), etc., respectively. Figures 6(a), 6(b) and 6(c) show the conventional closed switchboard (6a) -
It is a front view, a side view, and a top view which show an example. This closed switchboard (6a) is specified with a shock wave withstand voltage of 125 kV and a commercial frequency withstand voltage of 50 kV. The closed switchboard (6a) in each figure includes two transformers (7),
Bushing (12, 13>, connection conductor (14, Is),
It is composed of a supporting insulator (16), a bulkhead (17), a door (18), an outer cover (19), etc., and the closed switchboard (6) shown in FIG.
This constitutes the electrical connection within the dashed dot line shown in a). Also, the bushing terminal (12a) and flange (20) in Figures 6(a), (b) and (c) are respectively coupled to the conductor and jacket of the phase separation bus (4a) (Figure 3.4). Ru. The closed switchboard (6a) itself is fixed on the foundation (30) shown in the figures of FIG.

In the closed switchboard (6a) shown in Fig. 6(a), Fig. 6(b) and Fig. 6(c), a generator of about 10 to 20 kV is installed on the main circuit side, that is, the primary side of each built-in device. An operating voltage is always applied, and a voltage several times higher than this may be applied during abnormal conditions. The above-mentioned specifications such as shock wave withstand voltage of 125 kV were stipulated assuming high voltage in such abnormal situations, and in order to satisfy these specifications, the grounded outer sheath (19) and bulkhead (17) A predetermined distance is maintained between the door (18), etc., and the next side of the built-in equipment, and air insulation is maintained. As a result, the external dimensions of the closed switchboard (6a) cannot be reduced unnecessarily;
) and dimensions as shown in Figure 6(c), i.e. width 70
0ffffl, depth 1800m, height 2000m11.
Generally, the depth must be 3200 mm, taking into consideration the opening and closing of the door (18). This also applies to the other closed switchboards (6b, 6c), each of which requires predetermined dimensions.

On the other hand, as shown in Figures 3 and 4, each closed switchboard (
6a, 6b, 6c) must be installed in a limited space within the power plant building, and in that case, the
), opening and closing of #(1B) must be performed without any problem, and a predetermined maintenance space must be secured for the built-in equipment. Therefore, as shown in FIGS. 3 and 4, the closed switchboard (6a)
), and the two are connected by a fairly long phase separation bus (4a).Furthermore, the closed switchboard (6b) has a phase separation bus (4a) which is the main circuit. ) to ensure installation space.

[Problems to be Solved by the Invention] In the conventional closed switchboard for power generation main circuits as described above, it is difficult to coordinate the closed switchboard with predetermined dimensions with other equipment in the limited space inside the power plant building. The installation location must be determined carefully. Therefore, there was a problem in that a large amount of study time was required to formulate a layout plan for each device.

In addition, the phase separation bus (4) of the main circuit may be bent into a complicated shape, or the phase separation bus (4) of the main circuit and the closed switchboard (6a,
phase separation busbars (4a, 4b) connecting the
), there was a problem in that the manufacturing and installation costs of the entire electrical equipment related to the closed switchboard for the power generation main circuit increased.

This invention was made in order to solve the above-mentioned problems, and it is a power generation system that facilitates the layout design of electrical components related to a closed power distribution board for the power generation main circuit and reduces their manufacturing and installation costs. The purpose is to provide a closed switchboard for main circuits.

[Means for Solving the Problems] A closed switchboard for a power generation main circuit according to the present invention is filled with an insulating gas, is connected to a phase-separated busbar connected between a generator and a main transformer, and is connected to a phase-separated busbar connected between a generator and a main transformer. It is supported only by the phase separation busbar.

[Function] The closed switchboard for the power generation main circuit according to the present invention is made smaller and lighter by filling with insulating gas, and can be supported only by the phase-separated bus bar.

[Embodiment] Fig. 1 is a side view, including a partial top view, showing the equipment arrangement of a power generation main circuit including a closed switchboard for the power generation main circuit according to an embodiment of the present invention. FIG. 4 is a diagram corresponding to FIG. 4; In the figure, a generator (1), a main transformer (2), and a circuit breaker (5) are the same as those of the prior art.

The closed switchboards (6A) and (6B) are each, for example, the fourth
This corresponds to the conventional closed switchboards (6a) and (6b) in the figure, and each built-in device is the same as the conventional one. The closed switchboards (6A) and (6B) are directly attached to, supported by, and electrically connected to the phase separation bus (4). In the example shown in the figure, each closed switchboard (6A, 6B)
is suspended on the phase separation bus (4), that is, it is firmly supported without contacting the floor (31).

FIG. 2 is an enlarged view including a cross-sectional view of the closed switchboard (6A) and its vicinity in FIG. 1. In the figure, the grounded jacket (4E) of the phase separation bus (4) is connected to the conductor (4B).
A predetermined air insulation distance is maintained between the

The branched jacket (4E°) is provided by branching off from a part of the jacket (4E), and has a flange (21) formed at its tip. Furthermore, an inspection cover (22) is provided at the center of the branch jacket (4E'). The closed switchboard (6A) is hermetically closed by a jacket (19A) and a flange (18A), and a flange (20) is formed on the jacket (19A). The closed switchboard (6A) is attached to this flange (20
) and the flange (21) on the outside branch vt (4B') side with bolts etc., the phase separation bus (
4) is directly supported. Further, by this tightening, the jacket (19A) and the flange (18A) are grounded. A pair of transformers (7) are housed inside the closed switchboard (6A), and the bushings (12) are connected by connecting conductors (15A).
It is connected to the. The bushing terminal (12g) led out to the tip of the bushing (12) is connected to the phase separation bus (4) via a removable link (23).
) is connected to a branch terminal (4B'). In this way, the same electrical connection as before is achieved. Inside the closed switchboard (6A), SF6 gas is used as an insulating gas at a predetermined pressure, for example 0.5k.
g/cm It is sealed with a pressure of about 2G. Since SF6 gas has excellent insulation performance, it can meet the shock wave withstand voltage specification of 125 kV, which is the same as the conventional one, even with a much smaller insulation distance compared to conventional air insulation. In reality, even if an abnormal situation such as a drop in gas pressure occurs due to a slow leak of 10,000-SF6 gas, the insulation distance is sufficient to satisfy the withstand voltage performance, that is, 1 of the air insulation distance.
The insulation distance is approximately 73 to 1/4. Due to this reduction in the insulation distance, the external dimensions of the closed switchboard (6A) are also reduced, and the volume is reduced to, for example, about 1/1O, and the amount of ffi is also significantly reduced. As a result, the closed switchboard (6A) itself was not fixedly supported on the foundation, and the phase-separated busbar (4A) was not fixedly supported on the foundation.
) can be directly attached to any position on the path by the above-mentioned fixing method. Closed switchboard (6B
) is configured in the same way.

Therefore, the phase-separated bus (4) does not require the provision of a phase-separated bus for connection to a bent part or a closed switchboard as in the past, and the generator (1) and main transformer (2) can be effectively connected to each other. Since they can be connected in a straight line, a simple and neat power generation main circuit configuration can be achieved. In addition, the lower part of the bushing (12) and the transformer (7) are located inside the closed switchboard (6A), which is a sealed container filled with SF6 gas, and are completely isolated from the outside air, so dust and condensation may occur. As a result, the insulation performance of the bushing (12), transformer (7), etc. will hardly deteriorate.

On the other hand, in the event of a malfunction of the transformer (7) or a ground fault inside the closed switchboard (6A), the first thing to do is to
) After recovering the SF6 gas sealed in the flange (18A), the flange (18A) can be removed and inspected, or the transformer (7) can be replaced. Furthermore, after opening the inspection cover (22) and removing the removable link (23), the entire closed switchboard (7) can be removed and inspected by removing the bolts etc. that secure the flanges (20) and (21) to each other. be.

In addition, in the above embodiment, closed switchboards (6A) and (6B)
Although shown as being provided at the bottom of the phase separation bus bar (4), it may also be provided at the top or diagonally up and down. Although not shown in this embodiment, a conventional closed switchboard (6c)
(, Figures 3 to 5) also have closed switchboards (6a) and (
By employing a structure similar to 6b), similar effects can be achieved.

In addition, although the above example shows an example in which a circuit breaker (5) is installed in the main generating circuit, it is necessary to install a closed switchboard with the same electrical function even if a circuit breaker (5) is not installed. Therefore, similar effects can be achieved by applying the closed switchboard according to the present invention.

Furthermore, in the above embodiment, a removable link (2
3), but a manually operated disconnecting section may be provided in order to save labor in maintenance and inspection work and to simplify main circuit withstand voltage tests.

[Effects of the Invention] As described above, according to the present invention, the volume and weight of the closed switchboard for the power generation main circuit can be significantly reduced and reduced by filling insulating gas, and the closed switchboard can be supported only by the phase-separated bus bar. This has the effect of facilitating the layout design of equipment related to this closed switchboard.

Additionally, there is an effect that manufacturing and installation costs for each of the above-mentioned devices are reduced accordingly.

Furthermore, the filling of the insulating gas has the effect of making the closed switchboard virtually maintenance-free or at least extending the maintenance cycle.

[Brief explanation of the drawing]

FIG. 1 is a side view including a partial sectional view showing the equipment arrangement of the power generation main circuit including a closed power distribution board for the power generation main circuit according to an embodiment of the present invention, and FIG. 2 shows the closed power distribution board (6A) in FIG. 1.
Figure 3 is a plan view showing the equipment layout of the power generation main circuit including the conventional closed switchboard for the power generation main circuit, and Figure 4 is the line IV-IV in Figure 3. Figure 5 is a single line diagram of the power generation main circuit shown in Figures 3 and 4, Figure 6(a), Figure 6(b) and Figure 6(c).
) are a front view, a side view, and a plan view, respectively, showing an example of a conventional closed switchboard. In the figure, (1) is the generator, (2) is the main transformer, and (4) is the generator.
) is a phase-separated busbar, and (6A, 6B) is a closed switchboard. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] (1) A power generation main circuit closure characterized by being filled with insulating gas, connected to a phase separation bus connected between the generator and the main transformer, and supported only by this phase separation bus. switchboard.