JPH0564525B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention provides a bus bar and an insulating medium in a closed container.
The present invention relates to an optical ground road detection device for detecting a ground road accident that occurs in a gas insulated switchgear in which a disconnector, a cutoff switch, etc. are housed.

[Technical Background of the Invention] In substations or switchyards installed around large cities or coastal areas, electrical equipment constituting the substation or switchyard is moved to SF due to difficulty in obtaining land or to prevent salt damage. Gas insulated switchgear sealed with an insulating medium such as ₆ gas that has excellent insulation and arc extinguishing properties is used. This type of gas-insulated switchgear is constructed by arranging circuit breakers, disconnectors, and other necessary equipment three-dimensionally, narrowing the distance between each piece of equipment, and significantly reducing the site area. Therefore, it can be constructed significantly smaller than an air-insulated type switchgear.

By the way, it is generally known that the majority of failures in power transmission lines are recoverable due to arcing, etc., and only 10% of all failures result in permanent failures. Therefore, in many cases, power transmission can be continued by immediately cutting off a faulty power transmission line, making it de-energized, and then transmitting power to this section again. In this manner, when a ground fault occurs in an overhead line, the disconnector is temporarily opened and then closed again to limit the power outage to a single hour. However, if a ground fault occurs between the metal container and the busbar in gas-insulated switchgear,
Again, since it is impossible to restore the insulation,
It was necessary to reliably detect a ground fault and issue a signal to prevent the circuit breaker from reclosing to prevent a major accident.

Conventionally, the methods used to detect the occurrence of such ground faults are those that detect decomposition products produced by arcs generated inside metal containers, or those that detect the gas pressure inside metal containers. There were things that investigated changes. However, the method described above has the disadvantage that it cannot detect the arc generated by a ground fault unless it exceeds a certain level, and is therefore unreliable.

Therefore, in order to eliminate such drawbacks of conventional ground fault detection devices, a method for optically detecting ground faults has been devised. In this system, a ground fault arc light generated within a metal container is directly received by a light receiving sensor, and an optical signal is guided to an O/E converter via an optical cable to detect a ground fault accident.

FIG. 3 shows the above-mentioned optical ground fault detection device.
That is, the front end of the light receiving sensor 1 that receives the ground fault arc light is covered with a plastic cover 2 having a lens shape so as to have a light condensing effect, and the rear end of the light receiving sensor 1 is covered with the light receiving sensor 1. An optical fiber cable 4 is connected to transmit the optical signal received by the optical fiber 1 to the O/E converter 3, and the other end of the optical fiber cable 4 converts the transmitted optical signal into an electrical signal and transmits it to an external O/E output to control panel
Connected to the converter.

[Problems with the background art] Although attempts have been made to widen the light collection area using a plastic lens in the optical ground fault detection device configured in this way, the angle of the incident light with respect to the optical cable is There is a limit to the detection area of the arc light, and if this is provided on the side wall of the metal container, it will be necessary to install a large number of detection devices at regular intervals. In order to improve this, the present applicant has arranged the light receiving sensor 1 at the end or curved part of the metal container 5 so as to face the longitudinal direction of the metal container 5, as shown in FIG. We have proposed a device that can directly detect ground fault arc light 6 generated anywhere within a metal container with a small number of detection devices.

However, generally, as shown in FIG. 4, a post-type insulator 8 for supporting the conductor 7 is appropriately arranged inside the metal container 5, and as proposed by the applicant, an optical system is used. Ground fault detection device in metal container 5
If a ground fault occurs behind the insulator 8, the ground fault arc light 6 will be blocked by the insulator, and a sufficient amount of light will not be able to enter the light receiving sensor 1. First, there were some problems in that the accuracy of detecting ground faults deteriorated significantly, resulting in a lack of reliability.

In order to solve this problem, it has been considered to provide optical ground fault detection devices at both ends of the metal container, but this has the disadvantage that the number of devices increases and the cost increases significantly.

[Object of the Invention] The present invention was proposed in order to solve the problems of the optical ground fault detection device as described above. It is an object of the present invention to provide a highly reliable optical ground fault detection device that can reliably detect a ground fault occurring behind an object using a light receiving sensor placed on one side of a metal container.

[Summary of the Invention] The optical ground fault detection device of the present invention supports a conductor extending parallel to the longitudinal direction of a metal container by a post-shaped insulator provided between the inner surface of the metal container and the conductor, and supports one end of the metal container. A post-type insulator that supports the conductor is created by arranging a light-receiving sensor facing the longitudinal direction of the metal container, and arranging a mirror-like reflective part at a position facing the light-receiving sensor across the post-type insulator. Flash light caused by a ground fault occurring behind an object is reflected by the reflecting section and detected by a light receiving sensor.

[Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be specifically described based on FIG. 1. Note that the same members as those in the conventional example shown in FIGS. 3 and 4 are designated by the same reference numerals, and explanations thereof will be omitted.

As shown in FIG. 1, in this embodiment, the light receiving sensor 1 of the optical ground fault detection device is disposed at the end or curved portion of the metal container 5 to receive light in the longitudinal axis direction of the metal container 5. It is configured so that the sensor 1 is directed. Further, a mirror-surfaced reflecting portion 10 is provided at the other end opposite to the end of the metal container 5 in which the light receiving sensor 1 is provided.

In the optical ground fault detection device of this embodiment having such a configuration, a ground fault that occurs behind the side opposite to the light receiving sensor 1 of the post-type insulator 8 that supports the conductor 7 disposed inside the metal container 5 is detected. A reflective section 10 having a mirror surface is provided at a position facing the light receiving sensor 1 of the optical ground fault detection device to reflect the ground fault arc light 6 caused by an accident.
The reflected light 11 is detected by the light receiving sensor 1.

Further, the ground fault arc light due to a ground fault occurring on the light receiving sensor 1 side of the insulator 8 can be detected by the light receiving sensor 1 without being reflected by the reflecting section 10.

As described above, according to the present invention, it is possible to reliably detect a ground fault occurring behind the insulator 8 supporting the conductor 7 on the opposite side of the light receiving sensor 1 with one light receiving sensor. It is possible to prevent failure of detection, and to provide a highly reliable optical ground fault detection device.

Note that the present invention is not limited to the above-mentioned embodiments, and the reflective portion having a mirror surface is provided in the following manner.
It may be a lid part of a metal container as long as it is located opposite the light receiving sensor of the optical ground fault detection device. Further, as shown in FIG. 2, if the metal container 5 is very long, an insulating mirror layer 13 is formed on the surface of the insulating spacer
may be provided. As this insulating mirror layer 13,
As an example, a material in which a transparent epoxy resin is laminated on the surface of a white alumina-filled epoxy resin, which is generally used as the insulating spacer 12, is used.

[Effects of the Invention] As described above, according to the present invention, the light receiving sensor of the optical ground fault detection device is disposed at the end or curved portion of the metal container, and the light receiving sensor is directed in the longitudinal direction of the metal container. Furthermore, by providing a reflective part with a mirror surface at a position facing the light receiving sensor, the light receiving sensor can reliably detect ground faults that occur behind the post-type insulator that supports the conductor on the opposite side of the light receiving sensor. This has the effect of providing a highly reliable optical ground fault detection device that can perform

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing one embodiment of the arrangement of the optical ground fault detection device of the present invention, FIG. 2 is a sectional view showing another embodiment of the invention, and FIG. 3 is an optical ground fault detection device. FIG. 4 is a sectional view showing the arrangement of a conventional optical ground fault detection device. 1... Light receiving sensor, 2... Plastic cover, 3... O/E converter, 4... Optical fiber cable, 5... Metal container, 6... Ground fault arc light,
7...Conductor, 8...Insulator, 10...Reflector, 1
1... Reflected light, 12... Insulating spacer, 13...
Insulating mirror layer.

Claims (1)

[Claims] 1. To prevent ground faults occurring in gas-insulated switchgear,
In an optical ground fault detection device that collects the flash light with a lens, guides it to an optical fiber, and inputs the light into an O/E converter for detection, a conductor extending parallel to the longitudinal direction of the metal container is used. The metal container is supported by a post-shaped insulator provided between the inner surface of the metal container and the conductor, and a light-receiving sensor is placed at one end of the metal container facing the longitudinal direction of the metal container, and the light-receiving sensor is placed between the post-type insulator and the conductor. 1. An optical ground fault detection device characterized by having a reflective part having a mirror surface disposed at a position facing the . 2. The optical ground fault detection device according to claim 1, wherein the reflecting portion is disposed on a lid portion of an end of the metal container facing the light receiving sensor. 3. The optical ground fault detection device according to claim 1, wherein the reflecting portion is an insulating mirror layer formed on the surface of an insulating spacer disposed within a metal container.