JPH03225717A - Disconnecting switch - Google Patents

Abstract

PURPOSE:To reduce polarity difference of electric discharge between electrodes to decrease the number of generations of high frequency surge voltage by arrangedly installing expansion electrodes inside a hollow fixed electrode to constitute the fixed electrode such that it equivalently becomes a cylindrical electrode structure. CONSTITUTION:An electrode 4a made up in a hollow shape with an expansion electrode 20 arrangedly installed inside a fixed electrode 4a equivalently becomes a cylindrical electrode, and a movable electrode 6 and the electrode 4a become ones in approximately the same form of electrode. When a disconnecting switch is turned on, the electrode 6 enters into the inside of the electrode 4a such that the electrode 20 is pushed in by the electrode 6. At the time of breaking, the electrode 20 moves together with the electrode 6 by a spring member 22 and the lock 21a of a supporting electrode 21 is engaged with the lock 20a of the electrode 20. Resultantly, the electrodes 6 and 20 open and the electrode 6 moves in a fixed electrode 4b, so that the breaking operation is completed. Then, a quasi-uniform electric field is formed among the electrodes 6, 4a and 20, respectively, so that the polarity difference of arc discharge to be generated between the electrodes 6 and 4a decreases, and as a result, the number of reignitions of arc decreases, too. Frequency of generation of high frequency surge voltage, therefore, reduces.

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Field of Industrial Application) The present invention relates to a disconnector that can suppress high frequency surges.

(Prior Art) In recent years, gas-insulated switchgears have been widely used as switchgears for high-voltage circuits used in substations. This gas-insulated switchgear has a busbar, circuit breaker, disconnect switch, and other attached equipment housed in a grounded metal container, which is highly stable, inert, nonflammable, and sealed inside the grounded metal container. Insulation is maintained with an insulating gas such as SF6 gas, which is odorless, harmless, and has a dielectric strength two to three times that of air, and is used as a switchgear for high voltage circuits.

Such devices generally have a coaxial structure, and surges generated within the device propagate without being attenuated. Also,
It is a well-known fact that high-frequency surges are generated in gas-insulated switchgear due to the operation of disconnectors and circuit breakers.

In particular, when operating a disconnector, the rising part of the waveform is
5 ns, the maximum peak value of the following high frequency vibration of several MHz is more than twice the peak value of the constant operating voltage (2.0 pu
(above) surge voltage may occur. There are examples of dielectric breakdown accidents in oil bushings caused by the steep crest of such surges, and ground faults from arcs between the electrodes of disconnectors to grounded metal containers due to the wave height of surges. Cases of accidents have been reported. Furthermore, these surges are induced into the grounding system of gas-insulated switchgear, causing various radio interference and destruction of low-voltage control circuits. Therefore, it is necessary to suppress the high frequency surge generated within the gas insulated switchgear by some means.

One method of suppressing high frequency surges generated when such a disconnector is operated is disclosed in Japanese Patent Laid-Open No. 61-227325. That is, as shown in FIG. 2, a pair of fixed electrodes 4a and 4b are arranged close to each other in a grounded metal container 1 with their axes aligned and are supported and fixed by insulating spacers 2 and 2, respectively. Further, each of the fixed electrodes 4a, 4b is formed hollow, and contacts 5a, 5b are disposed on the inner peripheral surface thereof, respectively. Furthermore, a movable electrode 6 is provided in one of the fixed electrodes 4b, the outer peripheral surface of which is in contact with the contactor 5b, and which is slidable in the axial direction of the fixed electrode 4b. Contact 8 is attached.

Further, an operating mechanism 10 is provided outside the grounded metal container 1, and the operating force of the operating mechanism 10 is transmitted to the movable electrode 6 via the operating rod 9, and the movable electrode 6 is directed toward the fixed electrode 4a oppositely arranged. It is configured to be movable. This allows the fixed electrodes 4a, 4b to be brought into contact and separated.

On the other hand, cylindrical magnetic materials 16a and 16b are arranged on the left and right sides between the disconnector poles so as to surround the fixed electrodes 4a+4b. The surge is absorbed by the large inductance component of the magnetic materials 16a and 16b, thereby preventing the surge from propagating to the outside of the disconnector.

In addition, in the figure, 11 indicates a high voltage center conductor, and 12 indicates a connection electrode.

(Problems to be Solved by the Invention) However, the conventional disconnecting switch as described above has the following problems to be solved. That is, in the conventional disconnector, the fixed electrode 4a has a cylindrical shape;
The movable electrode 6 had a cylindrical shape, and the shapes of the two electrodes were different. Therefore, when the fixed electrode 4a and the movable electrode 6 of the disconnector are separated, the arc contact 8 provided at the tip of the movable electrode 6 is separated from the contact 5a provided on the inner peripheral surface of the fixed electrode 4a. Until the interruption operation is completed, an unequal electric field is formed between both electrodes. the result,
An arc is formed between the two electrodes for a long time, increasing the number of restrikes and increasing the number of occurrences of high frequency surge voltage. Therefore, for example, if a needle-like metal foreign object is present in the grounded metal container, the probability of dielectric breakdown will increase.

Therefore, there has been a strong desire to develop a disconnector that can reduce the occurrence of high-frequency surges and improve insulation performance.

The present invention has been made in order to solve the above-mentioned problems, and its purpose is to provide a disconnector with excellent insulation performance that can suppress the occurrence of high-frequency surges. .

[Structure of the Invention] (Means for Solving the Problems) The present invention provides a disconnector in which a fixed electrode and a movable electrode are disposed facing each other in a grounded metal container filled with an insulating gas. A retractable electrode configured to be expandable and retractable in the axial direction between the two electrodes is disposed inside the fixed electrode, and the fixed electrode is configured to equivalently have a cylindrical electrode JR structure. It is.

(Function) In the disconnector of the present invention having the above configuration, the fixed electrode is configured to have an equivalent cylindrical electrode structure, so that the tip surfaces of the fixed electrode and the movable electrode are each flat-shaped. , the electric field formed when the picture electrode is opened can be made into a quasi-uniform electric field. Therefore, the difference in polarity of discharge between the two electrodes is reduced, and the number of occurrences of high frequency surge voltage is also reduced.

(Example) Hereinafter, an example of the present invention will be specifically described based on FIG. Note that the same members as those of the conventional type shown in FIG. 2 are given the same reference numerals, and explanations thereof will be omitted.

In this embodiment, as shown in FIG.
A support electrode 21 is disposed inside a, and a retractable electrode 20 is attached to the tip of the support electrode 21 via a spring member 22. This expandable electrode 20 is formed to have substantially the same shape as the movable electrode 6 disposed opposite to it.

Further, a locking portion 20a is provided on the support electrode side of the expandable electrode 20.
is formed at the tip of the support electrode 21, and on the other hand, a locking part is formed at the tip of the support electrode 21 to engage with the locking part 20a of the expandable electrode to prevent the expandable electrode 20 from moving beyond a predetermined length towards the movable electrode. A locking portion 21a is formed.

Further, the expandable electrode 20 is configured to slide within the fixed electrode 4a while contacting a contact 5a disposed within the fixed electrode 4a.

In the disconnector of this embodiment configured in this manner, the hollow fixed electrode 4a is equivalently converted into a cylindrical electrode structure by the expandable electrode 20 that is extendably disposed within the fixed electrode 4a. Therefore, the movable electrode 6 and the fixed electrode 4a have substantially the same electrode shape. When the disconnector is turned on, the movable electrode 6 enters the fixed electrode 4a by pushing the expandable electrode 20 inside the fixed electrode 4a. On the other hand, when shutting off, the movable electrode 6 moves to the right in the figure, but the expandable electrode 20
The return force causes the movable electrode 6 to move toward the supporting electrode 21.
The movable electrode 6 and the expandable electrode 20 remain in contact until the locking portion 21a of the movable electrode 6 and the locking portion 20a of the expandable electrode 20 engage with each other. Thereafter, the two are separated, the movable electrode 6 moves into the fixed electrode 4b, and the interrupting operation is completed.

At this time, since the movable electrode 6 and the fixed electrode 4a are configured to have almost the same electrode shape, the period from when the movable electrode 6 and the expandable electrode 20 are separated until the interruption operation is completed is A quasi-uniform electric field is formed between the movable electrode 6, the fixed electrode 4a, and the expandable electrode 20. As a result, the polarity difference of the arc discharge generated between the movable electrode 6 and the fixed electrode 4a is reduced, so the number of re-ignitions between both electrodes is also reduced, and the number of occurrences of high frequency surges is also reduced.

In this way, according to this embodiment, by providing the expandable and retractable electrode within the fixed electrode 4a, the number of occurrences of surge voltage is reduced, and even if a metal foreign object is present in the grounded metal container, The probability of dielectric breakdown caused by this can be significantly reduced.

Note that the present invention is not limited to the embodiments described above, and a spring member used as a means for moving the expandable electrode in the axial direction of the fixed electrode and the movable electrode is disposed around the supporting electrode, and Similar effects can also be obtained by configuring the movable electrode to be biased toward the movable electrode. Further, the magnetic material used in the conventional type shown in FIG. 2 may be provided around the fixed electrodes 4a and 4b. Furthermore, although the embodiment shown in FIG. 1 uses the present invention in a single-phase disconnector, it can be similarly applied to a three-phase and three-phase bracket type disconnector.

[Effects of the Invention] As explained above, according to the present invention, the fixed electrode is configured to have a hollow shape, and the expandable electrode configured to be expandable and contractible is disposed inside the fixed electrode, so that the fixed electrode has an equivalent cylindrical electrode structure. By configuring as follows, it is possible to provide a disconnector having excellent insulation performance and capable of suppressing the occurrence of high-frequency surges.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing one embodiment of the disconnector of the present invention, and FIG.
The figure is a sectional view showing an example of a conventional disconnector. DESCRIPTION OF SYMBOLS 1... Grounded metal container, 2... Insulating spacer, 4a. 4b... Fixed electrode, 5a, 5b... Contact, 6...
・Movable electrode, 8... Arc contact, 9... Operating rod, 1°... Operating mechanism, 11... High voltage center conductor,
12... Connection electrode, 16a, 16b... Magnetic material, 2
0: Expandable electrode, 20a: Locking portion, 21: Support electrode, 21a: Locking portion, 22: Spring member.

Claims (1)

[Claims] In a disconnector in which a fixed electrode and a movable electrode are arranged facing each other in a grounded metal container filled with an insulating gas, the fixed electrode is formed into a hollow shape, and the inside thereof is expandable and contractible in the axial direction between the two electrodes. 1. A disconnector comprising a retractable electrode having a structure such that the fixed electrode has an equivalent cylindrical electrode structure.