JPH0457052B2 - - Google Patents

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to a disconnecting section of a closed switchboard.

(Prior Art) In FIG. 2, which shows a right side view of a closed switchboard to which a conventional closed switchboard disconnecting section (hereinafter referred to as a disconnecting section) is attached, a partition 1a vertically provided inside a box body 1 is shown. In front, there is a high voltage circuit breaker 1 at the bottom.
A circuit breaker chamber 2 is provided in which a circuit breaker 1 is housed in a manner that the circuit breaker chamber 2 can be freely drawn out, and a control supplies chamber 5 is provided above the circuit breaker chamber 2. , 5B are attached.

A partition 1b is provided between the middle part of the partition 1a and the ceiling part of the box body 1, and is partitioned into a busbar chamber 3 at the front and a cable chamber 4 at the rear. Partition 1
A is provided with an upper disconnection section 12 consisting of a bottomed cylindrical insulating tube and a conductor 16 at its axis, and a lower disconnection section 13 which is the same part as the upper disconnection section 12 at the bottom. At the front end of the conductor 16 embedded in the axis of the lower disconnecting section 13 and at the front end of the conductor 17 embedded in the axis of the lower disconnecting section 13, as shown in FIG. A plurality of main circuit contacts 19 attached to the rear end of the main circuit terminal 18 at the rear of the main circuit terminal 11 are engaged with each other. Upper and lower disconnection section 1
The circuit breaker 11 is pulled out to a disconnection position (not shown) on the front upper side of the circuit breaker 2, 13, and when the main circuit contact 19 is separated from the conductors 16, 17, the circuit breaker 11 is lowered in conjunction with the circuit breaker 11 being pulled out. Upper and lower disconnection section 1
Metal shutters 14 and 15 of ground potential are attached to shield the front of the shutters 2 and 13 as shown in FIG.

On the other hand, the lower end of a conductor 6A vertically arranged in front of the partition 1b is connected to the rear end of the conductor 16, and the upper end of this conductor 6A is connected to a horizontal busbar 6B passing through the box 1 from side to side. The rear end of the conductor 17 is connected to the front end of a conductor 7 disposed behind it, and the rear end of the conductor 7 is connected to the upper end of the cable 10 via a current transformer 8 attached to the rear surface of the partition 1b. It is connected to the compressed terminal 9.

By the way, even in closed switchboards, the standards specify that they can withstand commercial frequency voltages and lightning impulse voltages corresponding to the guaranteed insulation class, and are verified at assembly plants before shipping.

Therefore, in a disconnection section configured in this way,
The shutters 14 and 15 are connected to the disconnection section 1 as shown in FIG.
When descending in front of 2 and 13, conductors 16 and 17
The corner portion 20 of the fixed side contact portion at the front end of the shutter 14
or 15, the corner 20 is rounded with a radius of 5 to 10 mm in consideration of the fit of the main circuit contact 19. Even so, for closed switchboards with a rated voltage of 20 kV, distance X of 150 to 200 mm or more is required.

(Problem to be Solved by the Invention) However, because of this distance X, the depth of the box 1 increases, and the installation area of the closed switchboard also increases. Therefore, it is conceivable to provide a cylindrical metal ring around the outer periphery of the main circuit contact, but then there is a possibility that the fixing structure of the metal ring becomes troublesome.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a disconnecting section for a closed power distribution board that can easily increase the withstand voltage value and maintain the withstand voltage characteristics without increasing the depth of the closed power distribution board.

[Structure of the Invention] (Means and Effects for Solving the Problems) The present invention provides an insulating cylinder with a bottom in the rear partition wall of a circuit breaker chamber of a closed switchboard in which a circuit breaker is housed in a freely drawable manner. A conductor is coaxially buried in the bottom of this insulating cylinder, with a fixed side contact portion protruding forward that fits into the main circuit contact of the circuit breaker.
In the disconnection section of a closed power distribution board where the front of the insulating tube is shielded by a shutter whose front side is grounded when the circuit breaker is pulled out, a flange portion formed of a conductor and provided with the front surface exposed at the bottom of the insulating tube and a bottomed tube are used. The bottom part of the cylinder is placed forward, and the rear end is removably installed on the front surface of the flange part, and the metal cylinder is coated with insulation on the surface. The flashover voltage is improved, and the electric field at the front end of the fixed side contact part is relaxed with a metal tube, without increasing the external size of the closed switchboard.
This is a disconnecting section of a closed switchboard that is easy to manufacture and can increase the withstand voltage value between the shutter in front of the insulating cylinder and the front end of the fixed side contact part and maintain this withstand voltage characteristic.

(Example) Hereinafter, an example of the disconnecting section of the present invention will be described with reference to the drawings. However, parts that overlap with Figures 2 to 4 are omitted.

In FIG. 1, a disk-shaped flange portion 25 is formed in advance on the outer periphery at the intermediate portion of the conductor 26 embedded in the axis of the bottomed cylindrical insulating tube 21 made of epoxy resin of the disconnection portion 21. This flange portion 25
The front surface is flush with the bottom of the insulating cylinder 27.

On the front surface of the flange portion 25, a bottomed cylindrical metal tube 23, which has a rear end constricted inward and whose length in the axial direction is approximately the same as the fixed side contact portion protruding to the front portion of the conductor 26, is provided. 26, and its rear surface is fixed to the flange portion 25. This metal cylinder 23
An insulating coating 22 with a thickness of approximately 2 mm is applied to the surface of the cylindrical part in advance, and a circuit breaker 11 is inserted between it and the fixed side contact part of the conductor 26.
A gap is formed in which 9 is inserted and engaged.

In the disconnection section 21 configured in this way, the electric field at the corner 20 at the front end of the conductor 26 is relaxed by the metal tube 23 inserted inside the cylindrical portion of the insulating tube 27, so that the shutter 14, which shields the front, The withstand voltage value can be increased to 15. For example, JP-A-48-
The diameters of the buried electrode 23 shown in Figures 3 to 5 of JP-A-69058 and the buried electrode 16 shown in Figure 2 of JP-A-48-69069 are different because they are buried in the insulator 21. As it grew larger, JP-A-1988-
In contrast to the reduction in the electric field relaxation effect near the front end of the conductor 11 shown in Figures 3 to 5 of Japanese Patent Publication No. 69068 and Figure 2 of Japanese Patent Application Laid-Open No. 48-69069, Since the insulating coated metal cylinder 23 is coaxially provided in the gap between the insulating cylinder 27 and the conductor 26, it can be brought close to the fixed side contact part of the conductor 26, resulting in a small diameter, increasing the external size of the closed switchboard. The electric field near the front end of the fixed side contact portion can be effectively alleviated without causing any damage.

Furthermore, JP-A-48-69068 and JP-A-48-
Since the buried electrodes 23 and 16 shown in Publication No. 69069 are buried in the thick insulator 21, the operation can last for a long time due to the difference between residual stress during molding and hardening and thermal expansion due to energization/stopping after the start of operation. An embedded electrode 23,
There is a risk that the adhesive surface between 16 and the insulator 21 will peel off, which will cause minute corona discharge to occur, and tracking will be formed during long-term operation of the equipment, which may progress and cause an accident. The insulating coating 22 of the metal tube 23 of the disconnecting section 21 of the present invention is thin, has no residual stress, and does not peel off, so corona discharge does not occur even during long-term operation. Therefore, not only can the initial withstand voltage characteristics be maintained over a long period of time, but also the insulation coating 22 of the metal cylinder 23 can
Since it can be easily formed by, for example, flow coating without using a mold, it is easy and practical to manufacture.

[Effects of the Invention] As described above, according to the present invention, a bottomed cylindrical insulating cylinder is provided with the bottom part facing backward, on the rear partition wall of the circuit breaker chamber of the closed switchboard in which the circuit breaker is housed in a manner that the circuit breaker can be freely drawn out.
A conductor with a fixed side contact portion protruding forward that fits into the main circuit contact at the rear of the breaker is coaxially buried in the bottom of this insulating tube, and the front of the insulating tube is grounded when the breaker is pulled out. A flange part provided on the conductor in the disconnection part of the closed switchboard to be shielded, the front surface of which is exposed to the bottom surface of the insulating tube;
The bottom of the bottomed cylindrical shape faces forward, and the rear end is detachably attached to the front of the flange, and the metal tube has an insulating coating on its surface. The flashover voltage of the switchboard has been improved, and the electric field at the front end of the fixed side contact part has been alleviated using a metal tube, making it easy to manufacture and increasing the withstand voltage of the disconnecting part without increasing the external size of the closed switchboard. It is possible to obtain a closed switchboard disconnection section that can maintain its characteristics.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing an embodiment of the disconnecting section of a closed switchboard of the present invention, FIG. 2 is a side view showing the disconnecting section of a conventional closed switchboard, and FIG. 3 is an enlarged detail of the main part of FIG. 2. FIG. 4 is a diagram showing the operation of a disconnecting section of a conventional closed switchboard. 1... Closed switchboard, 11... Circuit breaker, 14...
Shutter, 19...Main circuit contact, 21...Disconnection section, 22...Insulation coating, 23...Metal tube, 25...
...Flange portion, 26...Conductor, 27...Insulating cylinder.

Claims (1)

[Scope of Claims] 1. A bottomed cylindrical insulating tube is provided on the rear partition wall of the circuit breaker chamber of the closed switchboard in which the circuit breaker is housed in a manner that the circuit breaker can be freely pulled out, and the bottom of the insulating tube is provided with the A conductor with a fixed contact part that fits into the main circuit contact of the circuit breaker protruding forward is coaxially buried,
In a disconnection section of a closed switchboard that is shielded by a shutter whose front side of the insulating tube is grounded when the circuit breaker is pulled out, a flange portion formed on the conductor and provided with a front surface exposed on the bottom surface of the insulating tube; , a metal tube whose bottom portion of the bottomed cylindrical shape faces forward, whose rear end is detachably attached to the front surface of the flange portion, and whose surface is coated with an insulating coating. Disconnect section of closed switchboard.