JPS6134805Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a closed switchboard that suppresses the generation of streamers by providing an insulating material on the edge of the metal shutter facing the conductor, thereby reducing the overall size of the switchboard.

Figure 1 is a single-line connection diagram showing a typical configuration example of a power system. In the diagram, BUS is a bus bar, CB bridge or disconnector, and CT is a current transformer. A conventional closed switchboard that constitutes the above-mentioned system is shown in FIG. 2, and its main parts are described in FIG. 3. Figure 2 shows the configuration of two feeders in the system shown in Figure 1, and in the figure, conductors 12 and 13 for the terminals of the shingle breaker 11 (corresponding to CB in Figure 1) are connected to the bulkhead 14. It faces the attached disconnection sections 15 and 16. In the illustrated position, the terminal conductors 12 and 13 are connected to conductors 17 and 18 on the disconnecting portions 15 and 16, as shown in FIG.

Here, one conductor 17 is connected to the bus bar 19 (see FIG. 1).
The other conductor 18 is connected to a device (not shown) by a cable via a current transformer 20 (corresponding to CT in FIG. 1).

The configuration of each part related to the disconnector 11 shown in FIG. 2 will be explained with reference to FIG.
When the conductors 17 and 18 on the 6th side are bare conductors, the distance between the poles of the shield breaker 11 is 2E, where E is the insulation distance equivalent to ground insulation from the end of the metal partition wall 21. becomes. When installing a metal shutter in such a structure, a metal shutter 22 having a width corresponding to the opening dimension A of the disconnecting portions 15 and 16 is used.
and 23 are located at the openings of the disconnecting sections 15 and 16. For this reason, the distance between poles of the cutter 11 was generally 2E+A. In addition, in order to reduce the distance between the electrodes, the main circuit conductors 12, 13 and 17, 18
It has been proposed to coat the wafer with an insulating material 24, 25 such as epoxy, but the creeping voltage characteristics of the coating are low, making it impossible to achieve a large reduction. Installing metal shutters 22, etc. is one of the important items for closed switchboards, and foreign standards such as IEC and ANSI stipulate that metal shutters be installed in the case of metal clad type. Reducing the distance between poles is a major challenge.

The purpose of this invention is to create a closed switchboard that can be downsized by reducing the distance between poles by covering the edge of the metal shutter facing the conductor with an insulating material and suppressing the generation of streamers from this edge. It is about providing.

The details of the present invention will be described below with reference to the embodiment shown in FIGS. 4 and 5. In FIG. 4, the same members as those in FIG. 3, which is a conventional example, are designated by the same reference numerals, and detailed explanation thereof will be omitted. In the metal shutters 31 and 32 of the present invention, a cover-shaped insulating material 33 is attached to the edge facing the terminal conductors 12 and 13 constituting the electric path, as shown in FIG. The distance C between the conductors 12, 13 and the metal shutters 31, 32 suppresses the occurrence of
can be significantly reduced.

An example of the flashover characteristics of the configuration shown in Figure 5 is shown in Figure 6.
This will be explained in comparison with a conventional example using figures. The thick broken lines and solid lines in FIG. 6 represent the conductors 12 and 1 shown in FIG.
3 has a diameter of 60 mm, and metal shutter 31,
This is an example of the characteristics when the distance C from 32 is changed. Further, the thin broken line and the solid line are characteristic examples of the conventional configuration under the same conditions, that is, when the insulating material 33 is not provided. As shown in the figure, when the opposing edge of the metal shutter 32 is a sheared surface without the insulating material 33, the negative voltage characteristic shown by the solid line is much lower than the positive characteristic shown by the broken line.

However, by covering the opposing edges of the metal shutter with the insulating material 33 as in the present invention, the negative characteristic shown by the solid line can be increased to near the positive voltage shown by the broken line. Generally, the impulse withstand voltage of a closed switchboard is specified as plus and minus voltages, and it is necessary to withstand both voltages. Therefore, as described above, increasing the negative characteristic to near the positive voltage indicates that it is possible to reduce the distance between electrodes.

For example, according to the ANSI standard, when the rated voltage is 15 ^kV ,
The impulse withstand voltage is specified as 95 ^kV , and in this case, the E dimension is generally 150 mm. Therefore, the minimum distance between poles in this case is 300 mm. If the shutter according to the present invention is used, the impulse withstand voltage can be withstood as long as the distance between the end face of the metal shutter and the main circuit is 40 mm, as shown in FIG. In this way, the opening size of the main circuit disconnection section can be maximized.
Even if it is 200 mm, the distance between poles will be 280 mm, so the distance between poles will be a value less than 2E + A, and it will be possible to reduce the size of the closed switchboard.

Furthermore, the present invention can be applied to a type without a main circuit disconnection section, as shown in FIG. In this case, the opposite edge of the partition wall 53 as well as the metal shutter 51 need only be covered with the insulating material 55, and the structure is extremely simple and the range of application is wide and the effect is great.

The insulating material provided on the opposite edge of the metal shutter includes an insulating cover, an epoxy flow coating, etc., and is applicable to all types of insulation.

Since the closed switchboard of the present invention is constructed as described above, the distance between the poles when the metal shutters are installed can also be twice the distance E, which is the insulation distance to the ground of the main circuit conductor, which is comparable to the conventional 2E. For 2E + A, which is the addition of the opening dimension A of the main circuit disconnection section, A
It becomes possible to reduce the size.

[Brief explanation of the drawing]

Figure 1 is a typical single-line connection diagram of a power system, Figure 2
3 is a partially enlarged view of FIG. 2, FIG. 4 is a side view of an embodiment of the closed switchboard according to the present invention, FIG. 5 is an enlarged view of the main parts of FIG. 4, 6th
The figure is a characteristic curve diagram showing an example of the characteristics of the present invention in comparison with the conventional one, and FIG. 7 is a side view of another embodiment of the present invention. 11...Shiya disconnection, 12, 13, 17, 18...
...Conductor, 31, 32...Metal shutter, 33...
Insulating material.

Claims (1)

[Claims for Utility Model Registration] A metal circuit breaker that is connected to and separated from a disconnection section provided in a partition wall in a box by a terminal conductor is housed in front of the partition wall, and that shields the front surface of the disconnection section when the circuit breaker is disconnected. A closed power distribution board provided with a shutter plate, characterized in that an insulating material having a U-shaped cross section is added to the terminal conductor side end of the metal shutter plate.