JPH0656791B2 - Fault arrester disconnecting device - Google Patents

Description

The present invention relates to a fault arrester disconnecting device for disconnecting a faulty arrester from a ground wire.

[Prior Art] A lightning arrester is installed on the transmission and distribution line in order to absorb an abnormal voltage due to a lightning strike and reduce equipment damage. If this surge arrester is damaged by receiving a lightning current exceeding the rated value and the follow-up current cannot be interrupted, or if a leakage current flows due to deterioration due to aging, etc., this surge arrester is removed from the power system such as the transmission line. It is necessary to disconnect it so that it does not hinder power transmission.

Conventionally, various devices for disconnecting a faulty arrester from a ground wire have been disclosed and implemented. The method of disconnection is whether the leakage current passes through the resistor provided in the disconnecting device to explode the explosive powder due to the heat generated by the resistor to destroy the container of the disconnecting device. Alternatively, a method of separating even a resistor by using a fusible substance that melts with heat when an electric current is passed has been adopted.

[Problems to be solved by the invention] However, the disconnecting device that destroys the container by using explosives or the like requires a large amount of explosive to destroy the container, and the sound generated during the disconnection operation is inevitably generated. It was large and there was a risk that the debris would be scattered and harm the public. To prevent this, Japanese Patent Publication No. 43-4888 discloses a device that uses a strong metal container and pushes it downward from a weak joint at the bottom of the container to separate it. Japanese Patent Publication No. 49-42298 discloses a separating device that makes a plastic container partly fragile so that it can be easily broken. However, the problem that fragments of the plastic container are scattered has been solved. Absent. In order to suppress the scattered matter as much as possible, it is necessary to provide a portion having a weak strength, and the strength of the lightning arrester disconnection device itself becomes weak, so that it is difficult to adopt it in a power transmission line.

In addition, since these disconnecting devices use a resistor that is normally used, only a large operating current and a long operating time can be obtained at the time of disconnecting. Therefore, the neutral point is not grounded. It could not be applied to the lines of the power system where the leakage current is very small like the system. Therefore, by using a resistor having a non-linear positive resistance temperature characteristic, a disconnecting device that operates with a minute current and a minute time is disclosed in Japanese Patent Laid-Open No.
It is disclosed in Japanese Patent No. 12900. However, this disconnecting device has an operating current of 10 amperes and an operating time of 2 seconds, and it has been desired that the operating current and the operating time be shorter. In addition, since a resistor or a resistor with a non-linear positive temperature characteristic is used, the operating current and operating time cannot be changed freely, and the required specifications can be changed according to the location of the transmission and distribution line. Could not be satisfied.

DISCLOSURE OF THE INVENTION The present invention eliminates the above-mentioned drawbacks, is strong in strength even when installed in an ultra-high voltage transmission line, has no scattered objects during operation, and can freely set the operating current according to the mounting location. Is provided.

[Means for solving problems]

The present invention for solving the above problems will be described with reference to FIG. 1 corresponding to an embodiment.

As shown in the figure, the fault arrester disconnecting device to which the present invention is applied has a first conductive portion 1, a piston 3, a second conductive portion 2 and a gas generator 4. The piston 3 is arranged in the cylinder 6 that constitutes the first conductive portion 1, is engaged with the cylinder 6 in the direction in which the second conductive portion 2 is located (the lower side direction in the figure), and is in the opposite direction ( It is movable in the upper direction of the figure). The second conductive portion 2 is connected to the piston 3. The first conductive portion 1 and the second conductive portion 2 are electrically connected. Gas generator 4
Is for detecting an abnormal current flowing from the first conductive portion 1 to the second conductive portion 2 to generate gas in the cylinder 6.

Although not shown, the first conductive portion 1 is connected to the power line, and the second conductive portion 2 is connected to the arrester. The first conductive portion 1 is connected to the lightning arrester, and the second conductive portion 2 is connected to the ground wire.

[Action]

The above described fault arrester disconnecting device of the present invention operates as follows.

When a lightning strike occurs in a power system such as a power transmission line and the lightning arrester operates normally, the first conductive portion 1 and the second conductive portion 2 are electrically connected to each other, so that the transmission line → the fault arrester disconnecting device (the first conductive portion) 1 →
The lightning current first flows in the order of the second conductive portion 2) and then the arrester (or the reverse order). After that, an AC current having a commercial frequency flows for a very short time, and then the insulation is restored to a normal state. At this stage, the gas generator 4 does not detect an abnormal current. Therefore, no gas is generated.

However, if the arrester fails, a small amount of commercial frequency current will continue to leak to the ground via the arrester. The gas generator 4 detects this leakage current (abnormal current) and generates gas in the cylinder 6. Then, the expansion pressure of the gas causes the piston 3 to move in a direction (upward direction in the drawing) opposite to the direction in which the second conductive portion 2 is present (the direction in which the second conductive portion 2 is locked). On the other hand, since the second conductive portion 2 contacts the edge of the cylinder 6,
It cannot move with the piston 3. Therefore, the connection between the piston 3 and the second conductive portion 2 is released. Furthermore, the second conductive portion 2 naturally falls as shown in FIG.
The first conductive portion 1 and the second conductive portion 2 are separated.

〔Example〕

Hereinafter, embodiments of a fault arrester disconnecting device to which the present invention is applied will be described in detail with reference to the drawings.

FIG. 1 is a vertical cross-sectional view showing an embodiment of the fault arrester disconnecting device of the present invention, and FIG. 2 is a vertical cross-sectional view showing the state after the operation.

The breakdown arrester disconnecting device shown in these figures includes a first conductive portion 1 including a cylinder 6 and an upper electrode 7 screwed into the cylinder 6, a second conductive portion 2 serving as a lower electrode, a piston 3 and a gas generator. Have four. The cylinder 6 is provided with a step 6a on its inner surface, and the piston 3 is also provided with a step 3a. When the piston 3 is inserted into the cylinder 6 and is in a fixed position, the steps 6a and 3a of the both are engaged with each other.
Above the cylinder 6 is a space 14 for moving the piston 3. Therefore, the piston 3 can slide in the upper direction of the figure, but cannot slide in the lower direction. Also piston 3
Is drilled from the upper part to the middle, and the gas generator 4 is inserted therein. A gas generating chamber 10 is formed at the tip of the hole, and a side hole 11 is opened from there. An O-ring 16 and an O-ring 1 are provided between the cylinder 6 and the piston 3.
Since it is sealed by 7, the gap 13 communicates with the gas generation chamber 10 but is hermetically sealed. The piston 3 is electrically coupled to the cylinder 6 by a shear pin 8, and the lower electrode 2 is attached to the portion protruding from the cylinder 6.
Are fitted and electrically and mechanically coupled by shear pin 9. The upper electrode 7 also serves as a stopper when the piston 3 moves. Further, the tip portions of the upper electrode 7 and the lower electrode 2 are connecting portions to the lightning arrester (or power line) and the ground line, and are threaded, but can be appropriately changed depending on the connecting method.

The gas generator 4 has a gas generating agent and an electric igniter in contact therewith. The gas generating agent may be explosive, but from the viewpoint of handling safety, a mixture of a metal azide and a metal oxide having a rapid gas generating rate is suitable. As the metal azide, for example, alkali metal azides such as sodium, potassium and lithium and metal azides such as magnesium, calcium and barium are preferable. As the metal oxide, for example, manganese oxide, nickel oxide or iron oxide is preferable.

Lead wire 4a connected to the electric igniter in the gas generator 4
And 4b pass through the hole of the upper electrode 7 by being insulated and sealed,
It is connected to a circuit that detects leakage current flowing due to a failure. As the detection circuit, a known circuit disclosed in Japanese Patent Publication No. 59-44677 can be used.
That is, as shown in FIG. 3, the detection circuit includes the detection coil 2
0, a rectifier circuit 21, a time constant circuit 22, a switching element 23, and a discharge resistor 24 can be used. According to this circuit, the setting of the current value for detecting the overcurrent flowing through the electrodes can be freely changed. For example, it is possible to set between 0.1 amp and several hundred amps, and it is possible to set the operating time to 0.1 seconds or less.

It should be noted that the cylinder 6, the piston 3, and the electrodes 7 and 2 described above are preferably made of a metal having a high conductivity and a strong strength. Since the place of use is a transmission and distribution line, it is exposed to natural environments such as wind and rain, so it is desirable to use stainless steel, which has excellent corrosion resistance. When using other metals, the surface must be corrosion-resistant, but since electrical connection is required, insulating corrosion-resistant treatment cannot be applied, so conductive corrosion-resistant treatment such as chrome plating must be applied. is necessary. Metals are used for the shear pins 8 and 9 because they have a role of electrical connection and a role of withstanding a mechanical load. As for the shape, it is appropriate to punch a round bar to an appropriate length or to tighten the screw part, and the outer diameter is selected within the range of 1 to 4 mm depending on the load bearing characteristics required by this device. do it. By changing the shear pin 9, it is possible to cope with the tensile strength between the electrodes. That is, in a place where a wind pressure is strongly received at a high place such as an ultra-high voltage power transmission, a shear pin having a high strength can withstand the wind pressure and shaking. Since the piston 3 moves by receiving pressure on the surface of the step 3a, the larger the difference in piston diameter, the smaller the gas generation pressure. Therefore, it may be designed according to the required strength, the size limitation of the entire device, and the like.

Next, the operation of the fault arrester disconnecting device of the above embodiment will be described.

When there is a lightning strike on the power system and the lightning arrester operates normally, first a lightning current flows in the order of the upper electrode 7, cylinder 6, shear pin 8, piston 3, shear pin 9 and lower electrode 2 (or vice versa), After that, commercial frequency of 200 ~
After the AC current of 400A flows for 0.01 seconds at maximum, the insulation is restored and the normal condition is restored. If the lightning arrester fails,
A small amount of commercial frequency current leaks to the ground via a lightning arrester. This leakage current causes a current to flow in the detection coil 20 of the detection circuit shown in FIG.
When the electric igniter in the gas generator 4 is energized via b, the gas generating agent is vaporized.

The generated gas flows from the gas generation chamber 10 through the side hole 11, and the gap between the cylinder 6 and the piston 3 sealed by the O rings 16 and 17 momentarily becomes a high pressure. Since the piston 3 is stepped, it is pushed toward a diameter having a large cross-sectional area, the shear pins 8 and 9 are cut, and the piston 3 is drawn into the cylinder 6 until it hits the upper electrode 7. Therefore, the lower electrode 2 falls and is electrically cut off.

Since the lower electrode 4 is fixed to the lightning arrester or the power line by an electric wire or the like, there is nothing to scatter and it is in a hanging state, and it can be confirmed from a distance that the fault arrester disconnecting device has been activated.

Experiment Cylinder 6, piston 3, electrodes 7 and 2 are made of stainless steel, and the gas generating agent is sodium azide 60.
Part and manganese dioxide 40 parts mixed powder 0.6g was incorporated in the gas generator 4. P16, P1 for different steps of piston 3
A 0 O-ring (JISB 2401) was used, the condition for detecting the leakage current was 6 A, and the gas generator was energized within 0.1 seconds when the current of 6 A flowed. The shear pin 8 for electrical connection is used as a stainless steel M2 screw (cutting load of about 1
30 kg), shear pin 9 for fixing electrodes is made of stainless steel M
Using the 3 screws (cutting load of about 300 Kg), the fault arrester disconnecting device shown in Fig. 1 is prototyped. The following current was passed between the electrodes 7 and 2 at both ends. First, when it was loaded with a lightning impulse current of 50 kiloamps with a waveform of 8 × 20 microseconds, it did not work, and when an alternating current of 6 amps was applied, it was found to be 0.
It started in 06 seconds, the piston 3 retracted, and the electrode 2 came off without sound. A ground wire of 1 m was attached to the separated electrode and attached to a utility pole, but the hanging state was confirmed even from a distance of 300 m.

〔The invention's effect〕

As described above, the failure arrester disconnecting device of the present invention is
This is a mechanism in which expanded gas for separating operation is generated in the cylinder, and the electrode is disengaged because the piston is drawn into the cylinder, and there is no scattered matter, and at the same time, explosion noise does not occur. Therefore, there is no danger of harming the public. on the other hand,
Since the electrodes come off and hang down, a faulty arrester can be easily found from a distance.

By using a current transformer and a failure detection circuit,
It is convenient because the operating current value can be changed freely. In other words, before the relay of the substation operates, the fault arrester disconnecting device can be adjusted so as to quickly detect and disconnect the faulty electric device, so that power transmission can be continued without a power failure.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of an embodiment of a fault arrester disconnecting device to which the present invention is applied, FIG. 2 is a diagram showing the state after the operation, and FIG. 3 is a leakage current detection circuit diagram. is there. 1 ... 1st conductive part, 2 ... 2nd conductive part 3 ... Piston, 4 ... Gas generator 4a, 4b ... Failure detection circuit lead wire 6 ... Cylinder, 7 ... Upper electrode 8.9 ... … Sherpin 10 …… Gas generation chamber, 11 …… Side hole 14 …… Movement space 16 ・ 17 …… O ring

Claims (1)

[Claims] Claim: What is claimed is: 1. A piston is movable in one direction and is retained in one direction at a fixed position in a cylinder forming a first conductive portion,
A second conductive portion is connected to the latching side of the piston,
A gas generator is provided which electrically connects the conductive portion and the second conductive portion, detects an abnormal current flowing from the first conductive portion to the second conductive portion, and generates expanded gas in the cylinder, and the gas pressure thereof is arranged. A failure arrester disconnecting device, characterized in that the piston is moved to release the connection with the second conductive part and disconnect the electrical connection between the first conductive part and the second conductive part.