JPH0729460A - Disconnector with resistor - Google Patents

Abstract

PURPOSE:To prevent the dielectric breakdown of an insulating cylinder creeping surface to an overvoltage generated according to switching operation to allow the supply of a small-sized resistor, and provide a small-sized disconnector capable of expecting stable serge absorbing effect by providing wrinkles on the insulating cylinder creeping surface of the resistor. CONSTITUTION:A movable side contact 12 and a fixed side contact 13 are provided opposite to each other in a sealed vessel 1. The movable side contact 12 has a movable contact 14 moved in such a manner as to be capable of connecting and disconnecting to the fixed side contact 13 by the force of a driving device 17. The fixed side contact 13 has a resistor 46 in parallel to the current carrying contact part formed of the movable contact 14 and the fixed side contact 13. Since an arc is generated between the top end of the resistor 46 and the movable contact 14 when the fixed side contact 13 and the movable contact 14 are opened, and a current is carried to the resistor, the serge is absorbed by the resistor. Wrinkles are provided on the surface of the resistor 46 to increase the creeping distance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disconnecting switch with a resistor provided with a resistor for suppressing an overvoltage generated when an opening / closing operation of a contact point contact portion.

[0002]

2. Description of the Related Art A gas-insulated switchgear adopting a gas-insulated system has been widely put into practical use in substations, switchyards, etc., for switching equipment and protecting equipment in the event of line failure. The gas-insulated switchgear contains a disconnecting switch, circuit breaker, grounding device, instrument transformer, lightning arrester, etc. necessary for opening and closing operations in a closed container. It is pressurized and sealed. These devices are
Each is supported and fixed by an insulating spacer and connected by a high voltage conductor.

The gas insulated switchgear is easy to open and close with high voltage and high power, has high reliability, and has high safety.
Since it has many excellent features such as compactness and excellent harmony with the environment, it is widely used today as the central equipment of power transmission and transformation equipment.

When switching the system, the circuit breaker or the disconnector installed in the gas insulated switchgear is used to disconnect or connect the system. In addition, the grounding device is used to ground the charging part when inspecting the equipment. When such an opening / closing operation is performed, an overvoltage that depends on the circuit configuration and the characteristics of these opening / closing devices is generated. This overvoltage is called switching surge, and because the surge level that occurs is extremely fast and the rise time of the surge is extremely fast from several nanoseconds to several tens of nanoseconds, it may threaten the insulation of the component equipment and also peripheral equipment. There is also a possibility that it may cause damage to, and suppression thereof is desired.

In particular, an overvoltage called a disconnector surge is generated at the time of opening / closing the disconnector, but it is necessary to suppress it because it is an extremely high value of several megavolts in the 1000 kV class power transmission currently under study. .

At present, as this method, a method of suppressing a surge through a resistor when the circuit is cut off or turned on is being studied, and for example, a disconnecting switch with resistance shown in Japanese Patent Application No. 4-107341 has been proposed. This is shown in FIG.

In FIG. 4, a movable side contact portion 12 and a fixed side contact portion 13 are provided inside the sealed container 11 so as to face each other. The movable contactor 14 slides directly between them to open and close the electric circuit. The movable contact portion 12 is a conductor 20.
And is attached to the closed container 11 via an insulating tube 15. In addition, the fixed-side contact portion 13 has the conductor 23.
And is attached to the closed container 11 via an insulating tube 16. The movable contactor 14 transmits the driving force obtained by converting the rotational motion into the linear motion by the drive device 17 installed on the upper part of the closed container 11 to the movable contactor 14 through the insulating operation rod 19. Driven by.

The fixed contact portion 13 is fixed to the conductor 23, and a resistor 46 is provided around the fixed contact portion 13 via a seat 48. An electrode 47 is attached to the other end of the resistor 46. The central portion of the electrode 47 has a structure in which the movable contact 14 can move in and out. The cross section of the electrode 47 facing the movable contact 14 is rounded into an arc shape, and
An arc-resistant metal 47a is attached to its tip.
Furthermore, the movable contact portion 12 is connected via the conductor 20,
The fixed-side contact portions 13 are connected to other devices via conductors 23, respectively.

In the disconnector having such a structure,
When the disconnector is turned on, the movable contact 14 comes into contact with the fixed contact 13 to energize. On the other hand, during the opening operation, the movable contactor 14 driven by the drive device 17 moves to the upper side in FIG. 4, and in the initial stage, the fixed contactor 13 and the movable contactor 14 are separated from each other to cause arcing to both ends thereof. To occur. Then, the movable contact 14 is further separated, and this time the resistor 4
An arc is generated between the arc-resistant metal 47a of the electrode 47 fixed to 6 and the movable contactor 14. Since the current at this time flows through the electrode 47 and the resistor 46, the surge energy is absorbed by the resistor 46 and the generation of overvoltage is suppressed.

During the closing operation, after an arc is first generated between the movable contact 14 and the arc-proof metal 47a,
The fixed contact 13 and the movable contact 14 contact each other. Therefore, the surge energy is absorbed by the resistor 46 at the initial stage of the closing when the overvoltage may occur, and the generation of the overvoltage is suppressed. Then, when the circuit closing operation is completed, the fixed side contactor 14 and the movable side contactor 14 are in a state of being completely in contact with each other, and electricity is supplied.

A wound resistor 46 shown in FIG. 5 has been proposed as a resistor used for such a purpose. This is a structure in which the resistance wires 51 and 52 are wound around a winding core 53 in opposite directions so as to be a non-inductive winding, and then molded with an insulator 54 such as epoxy resin. Further, electrodes 50 and 55 are attached to both ends thereof.

[0012]

However, the above disconnector has the following problems with the resistor 46. That is, the resistor 46 as described above
In order to suppress the disconnector surge that occurs, a resistance value of several hundred ohms to several kiloohms is usually used. However, when a surge occurs, an overvoltage determined by the circuit constant is directly applied to the resistor 46. If the voltage level at this time exceeds the dielectric strength of the resistor 46, dielectric breakdown occurs on the surface of the resistor 46. In such a case, the original surge suppression effect cannot be expected.
Therefore, it is necessary to secure a sufficient insulation distance so as not to cause insulation breakdown on the surface. For this purpose, it is necessary to increase the creepage distance of the resistor 46, and as a result, there is a problem that not only the resistor 46 itself but also the entire disconnecting switch becomes large.

The present invention has been proposed in order to solve the above-mentioned drawbacks, and improves the creepage dielectric breakdown characteristics of a resistor used in a disconnector with resistance to prevent the disconnector from increasing in size. Also, it is an object of the present invention to provide a disconnecting switch with resistance that always has a constant surge suppression effect.

[0014]

In order to solve the above-mentioned problems, the invention of claim 1 provides a movable contact and a fixed contact, which are freely contactable and separable, in an airtight container in which an insulating gas is sealed. A resistor is provided in parallel with the current-carrying contact portion composed of the movable contact and the fixed contact, and the resistor disconnecting switch suppresses a surge when the circuit is interrupted or turned on by the resistor. A fold is provided on the surface of the resistor.

According to a second aspect of the present invention, the resistor is formed by winding a resistance wire around a support serving as a winding core and casting the resistance wire with an epoxy resin. The invention of claim 3 is
The resistor is formed by sintering resistor powder.

[0016]

According to the disconnecting switch with resistance of the present invention having the above-mentioned structure, it is possible to improve the creeping dielectric strength of the opposing body by means of the folds on the resistor surface, and to obtain a constant surge suppressing effect. It is possible to provide the disconnecting switch with resistance and to downsize the device.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. The same parts as those in the prior art shown in FIG. 4 are designated by the same reference numerals and the description thereof will be omitted. (1) First Embodiment As shown in the sectional view of the whole disconnecting switch of FIG. 1, the resistor 45 is formed in a rod shape in the first embodiment and is supported by the conductor 23 of the fixed side contact portion 13 by the seat 48. At the same time, an electrode 47 having an arc resistant metal 47a is provided at the tip thereof. Further, shield electrodes 49 for relaxing the electric field are provided at both ends of the resistor 45.

As shown in the enlarged view of FIG. 2, the resistor 45 is provided with electrodes 60 and 65 at both ends thereof, and resistance wires 61 and 62 are wound around a winding core 63 in a non-inductive manner. There is. The resistor 45 is molded with an insulator 64 such as epoxy resin in a shape having a pleated surface. The shape of the pleats is not particularly limited, but in the first embodiment, in order to increase the creepage distance, for example, as shown in FIG. 2, a direction substantially orthogonal to the length direction of the resistor 45 is provided. It has a certain thickness and is shaped so that the tip portion has an arcuate cross section.

According to the first embodiment having such a structure, even if the overvoltage generated by the opening / closing operation of the disconnector is applied to the resistor, the insulator 6 molding the resistor 6 is used.
The creepage attached to the creeping surface of No. 4 improves the dielectric strength of the creeping surface. As a result, the creepage breakdown voltage can be increased and electrical breakdown of the resistor 45 can be prevented. Further, even when the resistor is contaminated by the decomposition products generated by the operation of the disconnector, it is possible to reduce the decrease in the creeping withstand voltage characteristic due to the effect of the pleats according to the first embodiment. Is also advantageous. Further, in the first embodiment, as shown in FIG. 1, since the shield electrodes 49 for relaxing the electric field are provided at both ends of the resistor 45, a local electric field rise caused when the electrode and the resistor are connected is prevented. Therefore, the creepage breakdown voltage characteristic of the resistor can be further improved. (2) Second Embodiment FIG. 3 shows a second embodiment of the present invention. The resistor 46 of the second embodiment has a resistance wire 7 around a cylindrical winding core 73.
1, 72 are wound, the periphery thereof is molded with a cylindrical insulator 74, and electrodes 70, 75 are provided at both ends thereof. In the second embodiment, the pleats are provided not only on the outer surface of the insulator 74 but also on the inner surface. According to the second embodiment having such a configuration, not only the structure of the resistor is simplified, but also the casting work of the insulator 74 is facilitated. Further, the weight of the resistor 46 can be reduced. (3) Other Embodiments The present invention is not limited to the above-described embodiments, and the pleats may be slightly inclined to make it easier to perform the casting operation. In each of the illustrated embodiments, the resistor is provided on the conductor 23 side that supports the fixed contact, but the resistor is provided on the movable contact and the conductor side that supports it. It can also be applied to disconnecting switches with resistance. Further, in the above-mentioned embodiment, the resistor is constructed by winding the resistance wires 51 and 52 in a non-inductive winding. However, as the resistor, for example, a ceramic resistor or a carbon resistor formed by sintering resistor powder to form a resistor. Similar effects can be expected by using a body or other metal film resistor. Also in this case, the creepage breakdown characteristic can be improved by attaching the pleats according to the present invention to the resistance surface or the surface of the insulating material covering these resistances.

Lastly, the above description has been made in the case of a disconnector as a disconnector with resistance, but the same applies to switchgear other than the disconnector, such as a grounding device. Also in this case, by mounting the resistor and the shield electrode according to the present invention on the fixed contact side, a certain surge suppressing effect can be expected without increasing the creepage distance.

[0021]

As described above, according to the present invention, it is possible to improve the creeping dielectric strength of the resistor by providing the creases on the creeping surface of the insulator in which the resistor is molded. Thus, it is possible to provide a disconnecting switch with resistance that always has a constant surge suppressing effect without increasing the total length of the resistor.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first embodiment of a disconnecting switch with resistance according to the present invention.

2 is an enlarged sectional view of a resistor portion in the first embodiment of FIG.

FIG. 3 is an enlarged sectional view of a resistor portion according to another embodiment of the present invention.

FIG. 4 is a cross-sectional view of a conventional disconnector with resistance.

FIG. 5 is an enlarged sectional view of a conventional resistor.

[Explanation of symbols]

 11 ... Airtight container 12 ... Movable side contactor 13 ... Fixed side contactor 14 ... Movable contactor 15, 16 ... Insulation cylinder 17 ... Driving device 19 ... Insulation operation rod 20, 23 ... Conductor 45, 46 ... Resistor 47 ... Electrode 47a ... Arc resistant metal 50 ... Electrodes 51, 52 ... Resistance wire 53 ... Winding core 54 ... Insulator 55 ... Electrode 60 ... Electrode 61, 62 ... Resistance wire 63 ... Winding core 64 ... Insulator 65 ... Electrode

Claims (3)

[Claims] 1. A movable contactor and a fixed contactor, which can freely come into contact with and separate from each other, are provided in an airtight container filled with an insulating gas so as to face each other, and the energizing contact portion composed of the movable contactor and the fixed contactor is provided. In a disconnector with a resistor provided in parallel with the resistor to suppress a surge at the time of interruption or closing of a circuit, a disconnector with a resistor characterized in that a fold is provided on a surface of the resistor. vessel. 2. The disconnector with a resistor according to claim 1, wherein the resistor is formed by winding a resistance wire around a support serving as a winding core and casting the resistance wire with an epoxy resin. 3. The disconnecting switch with resistance according to claim 1, wherein the resistor is formed by sintering resistor powder.