JPH0614767B2 - Optical method ground fault detector - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to an optical ground fault detector, and more particularly to a gas-insulated bus bar, a disconnector and a circuit breaker in which an insulating medium is enclosed in a sealed metal container. The present invention relates to an improvement of an optical ground fault detection device for detecting a ground fault accident occurring in a gas insulated switchgear.

[Technical background of the invention and its problems]

Generally, most transmission line failures are recoverable due to arcs, etc., and permanent failures are 10% of the total number of failures.
It is known to be nothing more than. Therefore, in many cases, if the faulty power transmission line is instantaneously cut off so as to have no voltage and then power is transmitted to this section again, the power transmission can be continued as it is. In this way, when a ground fault occurs on the overhead line, the circuit breaker is opened and then closed again so that the power failure can be kept in a short time. However, in a gas-insulated switchgear, if a ground fault occurs between the metal container and the bus conductor, the insulation cannot be restored again, so the ground fault can be reliably detected and the circuit breaker reclosed. It was necessary to issue a signal to prevent the accident and prevent a major accident.

Conventionally, there are various types of methods for detecting the occurrence of a ground fault in such a gas insulated switchgear, and of these, an optical method is available.

As shown in FIG. 3, the conventional optical ground fault detection device has a plastic shape in which the tip of the light receiving sensor 1 for receiving the ground fault arc light indicated by the dotted line has a lens shape so as to have a light collecting effect. The cover 2 is covered, and the optical fiber cable 4 for transmitting the optical signal received by the light receiving sensor 1 to the optical / electrical converting unit, so-called O / E converting unit 3, is connected to the rear end of the light receiving sensor 1. . The other end of the optical fiber cable 4 is connected to an O / E converter 3 which converts the transmitted optical signal into an electric signal and outputs the electric signal to an external control panel (not shown). The optical ground fault detection device configured as described above is the third conventional one.
As shown in FIGS. 4 and 5, it was arranged on the outer wall of the metal container 5. Then, the ground fault arc 7 generated by the ground fault accident between the metal container 5 and the conductor 6 supported via the insulating member 6a is detected.

However, although the optical ground fault detection device configured as described above has been attempted to increase the light collecting area by using a plastic lens, the angle of incident light with respect to the light receiving sensor 1 is limited. Therefore, the detection area of the ground fault arc 7 is limited. Therefore, when the optical ground fault detection device is arranged on the side wall of the metal container 5 as shown in FIG. 4, the ground fault arc 7 due to the ground fault accident occurring in the metal container 5 cannot be directly received, Since the scattered light of the ground fault arc 7 is detected and the light intensity becomes extremely weak, there is a problem that the detection accuracy is poor and the reliability is lacking.

Further, as shown in FIG. 5, the longer the distance L between the occurrence position of the ground fault and the arrangement position of the light receiving sensor 1 of the optical ground fault detection device, the more the light of the ground fault arc 7 inside the metal container 5. Since the number of reflections increases, and the intensity of scattered light weakens and it becomes difficult to detect. Therefore, as shown in FIG. 6, it is necessary to increase the number of locations of the optical ground fault detection device, which significantly increases the cost. However, the installation process was complicated.
Further, the surface of the light receiving sensor 1 is directly exposed to the ground fault arc 7, and the insulating gas 5a such as SF ₆ gas enclosed in the metal container 5 is blown into the atmosphere to induce a secondary accident such as a personal injury. There was a risk of

[Object of the Invention]

The present invention has been made in consideration of the above points, and an object of the present invention is to improve the light receiving efficiency, to reliably detect the occurrence of a ground fault accident, and directly to the ground fault arc light due to the ground fault. An object of the present invention is to provide a highly reliable optical ground fault detection device that is not exposed.

[Outline of Invention]

According to the present invention to achieve such an object, by arranging the light receiving sensor in the longitudinal axis direction of the metal container and arranging the light receiving sensor between the floating electrode and the metal container, the light receiving efficiency is improved and a ground fault accident occurs. It is characterized by reliably detecting the occurrence and preventing it from being directly exposed to the ground fault arc, thereby improving the reliability.

Example of Invention

An embodiment of the optical ground fault detection device of the present invention will be described below with reference to FIG. The same parts as those in FIGS. 3 to 6 are designated by the same reference numerals.

That is, the light receiving sensor 1 of the optical ground fault detecting device is arranged on the side wall of the metal container 5, and the plastic cover 2 having the light collecting effect of the light receiving sensor 1 is inserted and oriented in the longitudinal axis direction of the metal container 5. . The light receiving sensor 1 is attached to the support rod 9 of the floating electrode 8 and is arranged between the floating electrode 8 and the metal container 5. Furthermore, the hollow portion of the support rod 9
The optical fiber cable 4 is inserted through 9a, and the optical fiber cable 4 is led out to the outside so that the end of the support rod 9 is sealed by the sealing member 4a.

Further, the lid plate 10 of the pocket portion 10 protruding to the outside of the metal container 5
The supporting rod 9 is supported by a through an insulating member 11 so as to penetrate therethrough in a gastight manner, and a floating electrode 8 is installed at one end of the supporting rod 9 so as to face a conductor (not shown). Although not shown, the floating electrode 8 is grounded via a support rod 9.

With this configuration, the light of the ground fault arc due to the ground fault accident that has occurred inside the metal container 5 can be received directly from the longitudinal direction of the metal container 5 or with a few reflections. The intensity of the light is not weakened, and there is no risk of missed detection. Further, since the light receiving sensor 1 is not damaged because it is covered with the floating electrode 8 so as not to be directly hit by the ground fault arc, the insulating gas 5a enclosed in the metal container 5 as in the conventional case is not generated. There is no danger of blowing into the atmosphere and no secondary disaster will occur. Further, although the support rod 9 of the floating electrode 8 is normally grounded, it can be used for surge measurement such as switching surge. That is, there is an advantage that it can be used as a voltage detection device together with the optical ground fault detection device.

Next, another embodiment of the present invention will be described with reference to FIG.
The same parts as those in FIG. 1 are designated by the same reference numerals. A gear bar 12 is provided on the support rod 9 of the floating electrode 8. This gap portion 12 has a support rod 9 to which the floating electrode 8 is attached.
The electrode 12a provided on the other end of the pocket 12 and the electrode 12b facing the electrode 12a and having the gearup formed thereon are supported by the support rod 9a.
Fixedly supported inside the lid plate 10a of the support rod 9 and the support rod 9 is an insulating member 13
It is configured to be supported and fixed to the support rod 9a via.

The light receiving sensor 1 is attached to the support rod 9 via the support member 1a.
Is fixed so as to face along the longitudinal axis direction of the metal container 5, and is located between the floating electrode 8 and the metal container 5. The light receiving sensor 1 is an optical fiber cable 4
The optical fiber cable 4 is led out to the cover plate 10a via the sealing member 4a while maintaining airtightness to the outside. Further, a current transformer 15 for current detection is attached to the support rod 9a and led out to the outside in an airtight manner. A plastic cover 2 is attached to the light receiving sensor 1.

With this structure, when an abnormality such as a gas pressure drop occurs in the metal container 5, the voltage induced in the floating electrode 8 causes the gap in the gap portion 10 to cause a current transformer.
Although not shown, the signal detected by 15 is taken out as a trip signal of a circuit breaker or the like, so that it can be used as an abnormality monitoring device in addition to the effect of the embodiment of the present invention.

Further, although not shown, by disposing the light receiving sensors in the same position so as to be opposite to each other in the longitudinal axis direction, the mounting portion of the light receiving sensor can be reduced. Also, the same effects as those of the other embodiments can be obtained, and the advantage of reducing the price can be obtained.

〔The invention's effect〕

As described above, according to the present invention, the light receiving sensor of the optical ground fault detecting device is oriented in the longitudinal axis direction of the metal container, and the light receiving sensor is arranged between the floating electrode and the metal container to prevent a ground fault. It is possible to provide an optical ground fault detection device that reliably detects the light of the ground fault arc.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part of an optical ground fault detection device of the present invention,
FIG. 2 is a cross-sectional view of an essential part of another embodiment of the present invention, FIGS. 3 to 6 show a conventional optical ground fault detection device, and FIG. 3 is a partial cross-sectional perspective view showing the configuration arrangement. , FIG. 4 to FIG. 6 are cross-sectional views showing the arrangement and operation, respectively. 1 ... Light receiving sensor, 2 ... Plastic cover, 3 ... Optical / electrical converter, 4 ... Optical fiber cable, 5 ... Metal container, 6 ... Conductor, 7 ... Ground arc, 8 ... Floating Electrodes, 9, 9a ... Support rods, 12 ... Gearup parts, 15 ... Current transformers.

Claims (3)

[Claims] Claim: What is claimed is: 1. The flash light of a ground fault generated in a metal container of a gas insulated switchgear is condensed and guided to a light receiving sensor and an optical fiber cable, and this light is input to an optical / electrical exchange section. In the optical ground fault detecting device for detecting, the light receiving sensor is oriented in the longitudinal axis direction of the metal container and is arranged between the floating electrode and the metal container. 2. An optical ground fault detecting device according to claim 1, wherein the optical fiber cable penetrates through the inside of the support rod of the floating electrode. 3. The optical ground fault according to claim 1, wherein the floating electrode is provided with a gap portion on its support rod, and a current transformer for current detection is provided on the support rod on the metal container side. Detection device.