JP2007242293A - Insulating strength control structure of switch - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an insulating strength control structure wherein insulation between main circuits of different phases is coordinated, in a switch equipped with a stationary electrode and a movable electrode housed in an insulating case for every one phase. <P>SOLUTION: Intermediate electrodes 7 are horizontally fixed to the electrodes respectively by screws 8 on the upper side of the projecting wall 3b of the outer surface of an insulating case 3 so that their tip parts 7a face the outside. Discharge gaps are formed between the tip parts of the respective electrodes, the tip part of the screw 8 protrudes to the inside of the insulating case 3, and a discharge gap G2 is formed between the tip part and the head part of a stationary spring 10 in an arc distinguishing chamber 9. Thereby, insulating strength can be controlled so as to satisfy the following; insulating strength between the main circuit and the ground is less than insulating strength between main circuits of different phases, which is less than insulating strength between main circuits. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention is a method for controlling the insulation strength inside an opening / closing part used in a switch used for opening / closing an electric circuit such as a high-voltage distribution line. More specifically, the present invention relates to a configuration for controlling the insulation strength between different-phase main circuits in a switch in which a movable electrode and a fixed electrode are housed in an insulating case for each phase.

The high-voltage distribution line is provided with a fixed electrode for opening and closing the distribution line, and a cased switch that houses the opening and closing part of the movable electrode and the arc extinguishing chamber inside the main body case. For example, in order to maintain an appropriate margin for overvoltage generated by disconnector surges, switching surges, lightning surges caused by lightning, etc. that occur when a circuit breaker or switch is opened and closed, there is a difference in insulation strength. Since it is a conventional knowledge to make the connection priority, the insulation strength is defined as follows. It is necessary to increase the insulation strength in the order between the main circuit and ground <between different phase main circuit <in-phase main circuit (selecting the insulation strength in consideration of an appropriate margin as described above is called insulation coordination).

For example, in the invention described in Patent Document 1, in a switch in which a three-phase charging unit is collectively stored in a switch case, an electrode directed to a load side charging unit conductor whose tip is adjacent to the load side charging unit conductor is provided. There is a configuration provided.
Japanese Patent No. 3013770

However, in the invention described in Patent Document 1, it is effective in the case where the three-phase charging unit is stored in a lump, but the electrode is effective in the case where the charging unit is divided for each phase. It did not work and it was difficult to control the insulation strength between the different phase main circuits.

Therefore, even in a switch in which the electrodes for each phase as described above are housed in an insulating case, it has been a problem to control the insulation strength between the different-phase main circuits.

In the present invention, as described above, an insulating plate is used between the phases, so that both sides of the power supply can be handled. In the switch 1 having an insulating case 3 made of an insulating material in parallel in three phases, and having a fixed electrode 5 inside and a movable electrode 6 for opening and closing the fixed electrode 5, the insulation disposed at the center. On the outer side surface of the case 3 where the fixed electrode 5 is disposed, the electrode 7 made of a conductive metal material is disposed so that the arc-shaped tip portion 7a faces the adjacent insulating case 3, and both left and right sides Similarly, the electrode 7 is provided on the outer side surface of the insulating case 3 arranged on the outer side where the fixed electrode 5 is arranged, and the electrode 7 provided on the insulating case 3 and the fixing of the case 7 are provided. Release with electrode 5 A gap G2 is formed, and the electrode 7 provided in the central insulating case 3 and the tip portions 7a of the electrodes 7 provided in the insulating cases 3 on the left and right sides thereof face each other to form a discharge gap G1. In the invention according to claim 2, the main body case 2 is provided with an insulating case 3 made of an insulating material in parallel in three phases, and the fixed electrode 5 and the fixed electrode In the switch 1 provided with the movable electrode 6 for opening and closing to 5, the movable electrode 6 accommodated in the insulating case 3 disposed in the center has a maximum opening when the movable electrode 6 is opened. An electrode 22 located in the vicinity of the upper end of the insulating case and projecting on both sides, and a movable electrode 6 in the insulating case 3 disposed on both the left and right sides, have a discharge gap with respect to the tip of the electrode 22. G3 An insulating strength control structure for a switch, characterized in that it is provided with an electrode 20 made of a conductive metal material arranged to form the switch. 2 is an insulating strength control structure of a switch composed of 2;

According to the above invention, even in a switch in which an electrode is housed in an insulating case for each phase, the insulation strength between different-phase main circuits can be controlled, so that insulation coordination inside the switch can be achieved. .

In the first aspect of the invention, in an open state or a closed circuit state in which the power line is connected to the fixed electrode, even if an overvoltage due to an open / close surge or a lightning surge enters the high-voltage distribution line, the damage is minimized. Further, even when an internal short circuit accident of the switch occurs, damage to the switch can be suppressed to a small level.

Further, in the invention according to claim 2, in the open state in a state where the power line is connected to the movable electrode, even if an overvoltage due to an open / close surge or a lightning surge enters the high-voltage distribution line as described above, the damage is caused. Can be kept to a minimum.

Furthermore, in the invention according to claim 3, the insulation coordination can be achieved even in the open state and the closed state when the power line is connected to either the fixed electrode or the movable electrode. For this reason, when installing a switch on a utility pole, it can be installed without being aware of the power supply side or load side, so the installation work on the switch pole is improved. Can protect against overvoltage.

The best mode for carrying out the invention will be described with reference to the drawings.
1 to 4 show an embodiment of the present invention.

As shown in FIG. 1, the switch 1 has a main body case 2 made of a metal material with an open top and made of a bottom, for example, a stainless steel plate or a steel plate. The main body case 2 is divided into phases. Insulating case 3 made of an insulating resin material such as an epoxy resin or unsaturated polyester is provided in three phases, and these are fixed to base plate 4 with screws.

The insulating case 3 is formed in a substantially rectangular box shape with an open top, and a fixed electrode 5 and a movable electrode 6 are provided inside the insulating case 3 so as to face each other.
Further, through walls 3a penetrating the front and back are provided on both side walls where the fixed electrode 5 and the movable electrode 6 of the insulating case 3 are provided, and projecting walls 3b that are concentric with the through hole 3a and formed double. have.

Further, as shown in FIG. 3, an intermediate electrode 7 is provided as follows on the outer surface of the insulating case 3 on the side where the fixed electrode 5 is provided and above the protruding wall 3b. The intermediate electrode 7 has a substantially rectangular plate shape made of a metal material such as copper or stainless steel, and one end portion 7 a is formed in a substantially arc shape, and an elongated hole 3 b for mounting on the insulating case 3. It has.

On the outer side of the side where the fixed electrode 5 is disposed in the insulating case 3 disposed in the center, the tip 7a of the intermediate electrode 7 is horizontal so as to face the outside (the side of the insulating case 3 disposed on both sides). They are fixed to the insulating case 3 with screws 8. Further, the insulating case 3 arranged on both sides is similarly screwed to the insulating case 3 at a predetermined interval so as to face the front end portion 7a of the intermediate electrode 7 on the outer side surface on the side where the fixed electrode 5 is arranged. 8 (the discharge gap G1 is formed by the tip 7a of each intermediate electrode 7). Note that the predetermined interval in the above description is adjusted so that the insulation strength between the different phase main circuits is appropriate, and the mounting hole is formed in the intermediate electrode 7 by a long hole 7b so that the adjustment can be performed. (Refer to Fig. 4).

Further, as shown in FIGS. 1 and 2, the screw 8 fixing position of the intermediate electrode 7 attached to the three-phase insulating case 3 is such that the tip of the screw 8 protrudes inward from the side surface of the insulating case 3, and Is attached so that there is no space to shield the head of the fixing screw 10 of the arc extinguishing chamber 9 described later (discharging between the screw 8 and the fixing screw 10). A gap G2 is formed).

In the description of the present embodiment, the intermediate electrode 7 disposed in the center is configured by two members independently. However, the present invention is not limited to this form. For example, two intermediate electrodes 7 are joined. It may be a single member configuration. In this case, the predetermined distance between the intermediate electrodes 7 can be adjusted by moving the intermediate electrodes 7 provided on the left and right.

Next, the connecting conductor 11 made of a metallic conductive material is inserted into the through hole 3a provided in the insulating case 3 and fixed to the insulating case 3 by a screw fixing or press fitting method (not shown). They are electrically connected to a fixed electrode 5 and a movable electrode 6 described later. Further, a connecting portion 12a of a bushing 12, which will be described later, is attached to the connecting portion 11a protruding outward from the insulating case 3.

The fixed electrode 5 includes the connection conductor 11 and the fixed contact 13, and the plate-shaped fixed contact 13 made of a conductive metal material has two parallel planes provided on the connection conductor 11. Are supported by two pins 14 so as not to rotate.

Further, in order to extinguish the arc generated when the main circuit is opened, the fixed electrode 5 has an arc extinguishing chamber 9 made of urea resin or polyacetal resin material that generates arc extinguishing gas when thermally decomposed by arc heat. Is provided so as to cover the stationary contact 13. Further, on the outer surface of the arc extinguishing chamber 9, an iron material (not shown) for improving the arc extinguishing performance is provided in the vicinity of the fixed contact 13.

Further, the arc extinguishing chamber 9 is screwed to a mounting member 15 made of a conductive metal material having a substantially U-shaped cross section electrically connected to the connection conductor 11. On the other hand, the mounting member 15 is fixed with screws (not shown) so as not to rotate with respect to the insulating case 3.
With the mounting structure, the fixing screw 10 for fixing the arc extinguishing chamber 9, the fixed contact 13 and the connecting conductor 11 have the same potential.

The movable electrode 6 is composed of the connection conductor 11 and the movable contact 16, and the movable contact 16 is formed in an inverted V-shape that is curved, and is further formed in a crotch shape in parallel with another plate-like member 17. The movable contact 16 and the plate-like member 17 hold the two parallel planes provided with the connection conductor 11 and rotate with respect to the pin 18 penetrating the connection conductor 11. Supported as possible.
As shown in FIG. 2, a coil spring 19 is arranged in a compressed state coaxially with the pin 18 at the rotation fulcrum of the movable contact 16, and the connection is made by a predetermined pressure by this biasing force. The conductor 11 is held.

The joint between the movable contact 16 and the plate-like member 17 is fixed as follows with a bolt 20, a screw 22 and a nut 21 made of a metal material such as stainless steel. In the movable contact 16 inside the insulating case 3 disposed in the center, a screw 22 protruding a predetermined amount on both sides is passed through a mounting hole (not shown) formed in the joint, and then 2 from both sides. The plate-like members 16 and 17 are tightened with nuts 21 so as to sandwich the plate-like members 16 and 17 and fixed with screws. With this structure, the movable contact 16 and the connecting conductor 11 and the screw 22 are at the same potential.

Further, in the joint portions 16a of the movable contacts 16 located on both sides, a screw portion of a bolt 20 in which a head portion and a screw portion are integrated with a conductive metal material, for example, a stainless steel material, is not shown. In order to sandwich the movable contact 16 and the plate-like member 17 from the side opposite to the head of the bolt 20, the nut 21 is tightened and screwed. The tip portions of the bolts 20 and screws 22 provided on the three-phase movable contact 16 are configured to face each other at a predetermined interval, and at the maximum open position of the movable electric contact 16, The front ends of the bolts 20 and the screws 22 are arranged in the vicinity of the upper end surface of the insulating case 3 (a discharge gap G3 is formed between the front ends of the screws 22 and the bolts 20).

The predetermined interval is set so that the insulation strength between different phases becomes an appropriate value even when the movable contact 16 is at the maximum open position with respect to the fixed contact 13.

As shown in FIG. 1, the bushing 12 is attached through both sides of the body case 1, and a conductive material is provided at the center of the bushing 12 made of an insulating resin material such as epoxy resin or porcelain. 12a is integrally formed.
Further, a hollow pipe-shaped connecting portion 12b made of, for example, a copper material made of a conductive material is press-fitted into the distal end portion of the conductor 12a provided in the central portion of the bushing 12.

By connecting the bushing 14 having the above structure to the main body case 1 by a known method, the connecting portion 12b of the bushing 14 is press-fitted into the connecting portion 11a of the connecting conductor 11, and the connecting conductor 11 of the bushing 14 is the movable electrode. 5 and fixed electrode 6 are electrically connected. The cylindrical portion 12 c of the bushing 12 connected to the main body case 1 is inserted between the protruding portions 3 b provided on the insulating case 3 to form an insulating space.

With this insulating space, the space insulating distance from the charging part (conductor 12a or connecting conductor 11) to main body case 1 can be extended. That is, the charging distance passes through the space between the protruding wall 3b (inner side) and the cylindrical part 12c, and then passes through the space between the cylindrical part 12c and the protruding wall 3b (outer side) to reach the main body case 1 to increase the insulation distance. This improves the insulation performance.

Next, with reference to FIGS. 1 and 2, the operation of dielectric breakdown between the different phase main circuits in the above configuration will be described. When an overvoltage is applied to the power line in the state where the switch 1 is turned on, the operation is as follows. Since the insulation strength is set to be the weakest between the main circuit and the ground, first, a breakdown occurs between the main circuit and the ground, and then a breakdown occurs between the different-phase main circuits. Here, the description of the operation of dielectric breakdown between the main circuit and the ground is omitted.

The dielectric breakdown between the different-phase main circuits is caused by the fixed screw for fixing the arc extinguishing chamber 9 attached to the fixed electrode 5 of each of the three phases by increasing the pressure of the fixed electrode contactor 13 and the connecting conductor 11 due to overvoltage. 10 is boosted, and dielectric breakdown occurs between the tip portions of the screws 8 fixing the intermediate electrode 7 (discharge occurs from the discharge gap G2). As a result, after the intermediate electrode 7 is boosted, dielectric breakdown occurs between the intermediate electrodes 7 (discharge occurs from the discharge gap G1), and dielectric breakdown occurs between the different-phase main circuits. At this time, although the voltage provided to the movable contact 16 is also boosted in the same manner, the insulation strength is higher than that between the different-phase main circuits because it is housed in the insulating case 3, so that the movable contact Insulation breakdown does not occur between the sub-elements 16.

Moreover, in the open state of the switch 1, it is as follows. When the power supply line is connected to the fixed electrode portion 5 side, it is omitted because it is the same phenomenon as in the above-described input state.
When an overvoltage is applied to the power supply line when the power supply line is connected to the movable electrode 6 side, the respective movable contact 16 and connection conductor 11 are boosted, and first, the insulation breakdown between the main circuit and the ground Next, dielectric breakdown occurs between the different-phase main circuits. Between the different phase main circuits, the movable contact 16 is boosted by an overvoltage, and at the same time, the bolt 20 and the screw 22 provided on the movable contact 16 are also boosted.
Since the tips of the bolts 20 and the screws 22 that are boosted with each other face each other, dielectric breakdown occurs between them.

As described above, according to the configuration of the present invention, the insulation strength can be controlled such that the ground strength <between different phase main circuits <between main circuits regardless of whether the switch 1 is opened or closed.

Sectional drawing from the front side of the switch which is an Example of this invention Plan view showing the three-phase insulation case in FIG. Side view from fixed electrode side in FIG. Front view of intermediate electrode

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Switch 2 Main body case 3 Insulation case 5 Fixed electrode 6 Movable electrode 7 Intermediate electrode 8 Screw (for intermediate electrode)
9 Arc extinguishing chamber 10 Fixing screw (for arc extinguishing chamber fixing)
15 Mounting bracket 20 Bolt 22 Screw G1 Discharge gap (between intermediate electrodes)
G2 Discharge gap (between intermediate electrode and fixed electrode)
G3 Discharge gap (between movable electrodes when opened)

Claims (3)

In the switch 1 provided with an insulating case 3 made of an insulating material in the body case 2 in three phases in parallel, and provided with a fixed electrode 5 and a movable electrode 6 for opening and closing to the fixed electrode 5,
On the outer side surface of the insulating case 3 arranged in the center on which the fixed electrode 5 is arranged, an electrode made of a conductive metal material is arranged so that the arc-shaped tip 7a faces the adjacent insulating case 3 7 and
Further, the electrode 7 is similarly provided on the outer side surface of the insulating case 3 disposed on the left and right sides where the fixed electrode 5 is disposed, and the same case as the electrode 7 provided on each of the insulating cases 3 is provided. 7 to form a discharge gap G2.
Insulation of a switch characterized in that the electrode 7 provided in the central insulating case 3 and the tip portions 7a of the electrodes 7 provided on the left and right insulating cases 3 face each other to form a discharge gap G1. Strength control structure. In the switch 1 provided with an insulating case 3 made of an insulating material in the body case 2 in three phases in parallel, and provided with a fixed electrode 5 and a movable electrode 6 for opening and closing to the fixed electrode 5,
The movable electrode 6 accommodated in the insulating case 3 disposed in the center includes an electrode 22 located near the upper end of the insulating case when the movable electrode 6 is fully opened, ,
Furthermore, the movable electrode 6 in the insulating case 3 arranged on both the left and right sides is provided with an electrode 20 made of a conductive metal material arranged to form a discharge gap G3 with respect to the tip of the electrode 22. Insulation strength control structure of a switch characterized by being provided. An insulating strength control structure for a switch comprising the switch according to claim 1 and claim 2.

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