JPH0611470Y2 - Optical current transformer for gas insulated switchgear - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Use of the Invention] The present invention relates to an optical current transformer for a gas insulated switchgear (hereinafter abbreviated as GIS), and an optical current transformer (hereinafter abbreviated as optical CT). The optical CT for GIS capable of transmitting an optical signal from the detection unit of the above to the outside of the closed container on the ground side from the charging unit side without impairing the insulation performance.

[Background of the invention]

The optical current transformer is fitted to a high-voltage conductor (charging part) as described in, for example, the announcement of the presentation number 642 "Basic performance of all-glass optical CT" at the 1987 National Congress of the Institute of Electrical Engineers of Japan. It is configured using a lead glass prism (detection unit) that uses the Faraday effect. An optical fiber is used to connect an optical fiber between the detecting unit provided on the charging unit side of the optical CT and the light emitting unit and the light receiving unit provided on the ground side.

An example of the structure of this all-glass optical CT is shown in FIG.
That is, the optical signal from the light emitting diode 1 which is the light emitting portion is guided by the optical fiber 2 to the detection portion 4 which is installed by being fitted into the high voltage conductor 3. Then, the optical signal passes through the glass prism 5 and the polarization prism 6 in the detection unit 4, and is guided to the photodiodes 7A and 7B serving as the light receiving units by the other optical fibers 2A and 2B, where the electric signal is converted from the optical signal. Is converted to. In such an optical CT, the light emitting portion and the light receiving portion are provided on the ground side of the closed container that houses the high voltage conductor 3, and the detecting portion is provided on the high voltage conductor side which is the charging portion, and the electrical connection between them is provided. Optical insulation is provided by optical fibers.

When this type of optical CT is incorporated in GIS, it is necessary to sufficiently consider insulation. That is, the feature of GIS is that it is miniaturized by utilizing the effect of enclosing SF ₆ gas having high dielectric strength and improving the insulation characteristics. Therefore, since the insulation distance between the high voltage side and the ground side in the sealed container is short, the optical fiber used for the optical CT for GIS generally has a voltage 10 times or more larger than that in the air system per unit length. Will be added. Further, since the dielectric constant of the optical fiber is about 5 to 10 times larger than that of the insulating gas of GIS, the electric field is concentrated and the insulating performance of GIS is deteriorated.

Therefore, a method of transmitting an optical signal in the gas space is also under study. FIG. 2 is an example of gas space transmission applied to the all-glass optical CT of FIG. The optical signal from the light emitting diode 1 is guided to the lens 8 by the optical fiber 2, and the optical signal incident on the insulating gas from the lens 8 propagates in the insulating gas as indicated by the arrow and is opposed to each other. The light is guided to the optical fiber 2 from the lens 8 installed on the charging section side.
Then, the optical signal passing through the detection unit 4 passes through the polarizing prism and is reflected by the optical fibers 2A and 2B to the lens 8 respectively.
An optical signal guided to A and 8B and made incident on the insulating gas from the lenses 8A and 8B propagates again in the gas and is transmitted from the lenses 8A and 8B facing the ground side to the optical fiber 2.
Be led to. The optical signals guided to the photo diodes 7A and 7B by the optical fibers 2A and 2B are converted from the optical signals into electric signals as in the conventional case.

However, since the transmission of the optical signal between the charging section side and the ground side by this method is performed in the gas space, the insulation performance does not deteriorate as in the optical fiber method. However, since the optical signal is transmitted through the gas space in GIS,
Since the light emission phenomenon inside the IS (for example, the arc light when the current is cut off, the preceding arc light when the current is turned on, etc.) acts as a disturbance noise on the optical signal of the optical CT, the accuracy of the optical signal in this space transmission method is high. ， It causes a problem on signal stability.

Further, in the above-mentioned optical signal space transmission method, since the optical signal is transmitted in the gas space, it is necessary that the optical axes of the light-transmitting side lens and the light-receiving side lens are aligned.
It is extremely difficult to align the optical axis within GIS
The optical axis may be displaced due to the vibration during operation of the IS circuit breaker and the vibration due to the electromagnetic force when a large current flows due to an accident such as a ground fault, resulting in low reliability in optical signal transmission. I got it.

[Purpose of device]

An object of the present invention is to provide an optical CT for GIS that has high insulation performance and high optical signal transmission reliability.

[Outline of device]

The optical CT for GIS of the present invention is provided with a detecting portion of an optical current transformer so that an optical signal goes around the high-voltage conductor at intervals and is arranged in a hermetically sealed container. In addition, an insulating material formed so that a hollow portion serving as an optical transmission line penetrates therethrough is provided between the detection portion and the optical fiber.

[Example of device]

An embodiment of the present invention will be described below with reference to FIGS. 3 to 5. 3 (a), (b), and (c) show examples of the insulator 9 used in the optical CT for GIS which is placed in the closed container of the present invention. This (a) is an example of a cylindrical insulator 9 having three optical transmission lines arranged in a triangular shape,
(B) is an example of the insulator 9 having one optical transmission line,
Further, (c) is an example of the insulator 9 having three optical transmission lines arranged in parallel.

The insulator 9 forms a hollow portion 16 penetrating the inside thereof as shown in FIGS. 3 (a), 3 (b) and 3 (c), and both ends thereof are formed to be flat. And
Lenses 8, 8A and 8B are fixed to both ends of the hollow portion so as to face each other, and the inside of the insulator 9 is used as a transmission path of an optical signal. Therefore, the optical fibers 2, 2A, 2B reaching the detector side of the optical CT are opposed to the lenses 8, 8A, 8B fixed to one side of the insulator 9, and the lens 8, 8A, 8B fixed to the other side. Opposed to 8A and 8B are optical fibers 2, 2A and 2B, which are provided on the ground side of the closed container and reach the light emitting portion or the light receiving portion of the optical signal. Therefore, the optical signal transmitted from the ground side to the lens 8 at one end from the optical fiber 2 is condensed, and the hollow portion 1 which is a gas space in the insulator 9 is collected.
The optical fiber 2 enters the optical fiber 6 and is condensed by the lens 8 at the other end and sends out an optical signal to the optical fiber 2 reaching the detecting portion. On the contrary, the optical signal from the detecting portion side forms an opposite path.
It is transmitted to the ground side by B and the lenses 8A and 8B.

Here, the insulator 9 is formed as a GIS insulator by using a reinforced plastic (FRP) which is a widely adopted epoxy resin or glass fiber as a reinforcing material.

An example in which the above-described present invention is applied to a gas circuit breaker is shown in FIG. 4, and an example in which it is applied to a GIS disconnector is shown in FIG. In the gas circuit breaker, as shown in FIG. 4, a bushing 14 is established above a grounded tank 10 which is a closed container, and a breaking portion 1 is provided in a part of the high voltage conductor 3 between the bushings 14.
1 is formed, and the operation of the cutoff portion 11 is performed by the insulating operation rod 12 which is an insulator connected to the operation mechanism portion 13, and the optical CT 4 and the ground tank 10 provided in the high voltage conductor 3 portion. Transmission of an optical signal between the light emitting portion and the light receiving portion provided on the side is performed by utilizing the insulating operation rod 12 formed as shown in FIG. Similarly to this, in the case of the disconnector, as shown in FIG. 5, a disconnector 15 formed in a part of the high-voltage conductor 3 arranged in the conduit 17 which is a closed container is provided in the operation mechanism unit 13. When the insulated operating rods 12 are connected in series, the insulating operating rods 12 are used as a part of the transmission path of the optical signal of the optical CT.

In each of the above-described embodiments, since the normally used insulator is used as the transmission line of the optical signal of the optical CT, the optical performance between the charging section side and the ground side is maintained without impairing the insulation performance of the optical CT for GIS. Since a signal can be transmitted and a lens fixed to both sides of the insulator is used, the optical axis does not shift due to vibration, etc., and the influence of ambient light can be significantly reduced. The transmission reliability can be improved.

In the embodiment of the present invention, since the end surface of the insulator is a flat surface and the lens is fixed to this flat surface, it is easy to adjust the optical axis of the lens at both ends of the hollow portion when mounting the lens. become.

[Advantages of the Invention] According to the present invention, the optical signal is transmitted by using the insulating portion provided with the hollow portion serving as the optical transmission path inside.
It is possible to provide a highly reliable optical transmission line having high insulation properties, resistant to disturbance noise light and vibration, and improving the reliability of the optical CT for GIS.

Further, according to the present invention, since the optical CT detector is provided in a non-contact manner with the high-voltage conductor, the high-voltage conductor and the insulator serving as the optical transmission line are in non-contact with each other, and the insulator is not affected by accident current or the like. It is not affected by vibration of the conductor when a current is applied or thermal stress caused by thermal contraction of the conductor due to temperature change. As a result, a more stable spatial transmission path for optical signals can be secured.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a conventional optical CT, FIG. 2 is a schematic configuration diagram of a conventional spatial transmission type optical CT, FIG. 3 (a),
(B) and (c) are configuration diagrams showing an embodiment of an insulator used in the optical CT for GIS of the present invention, respectively. FIG. 4 is a schematic diagram showing an example of a gas circuit breaker to which the present invention is applied, and FIG. FIG. 3 is a schematic view showing an example of a disconnector to which the present invention is applied. 1 ... Light emitting diode, 2, 2A, 2B ... Optical fiber,
4 ... Optical current transformer, 7A, 7B ... Photodiode, 8, 8
A, 8B ... Lens, 9 ... Insulator, 16 ... Hollow part.

Claims (2)

[Scope of utility model registration request] 1. A high-voltage conductor is arranged in a hermetically sealed container containing an insulating gas, an optical current transformer for detecting light is provided in the high-voltage conductor, and an optical signal from this optical current transformer is transmitted through an optical fiber. In a gas-insulated switchgear that transmits to an external light-receiving part or light-emitting part, between the optical current transformer and the optical fiber that optically converts the magnetic flux from the high-voltage conductor and detects the optical signal circulating around the high-voltage conductor. Or, an optical current transformer for a gas insulated switchgear, characterized in that an insulator having an optical transmission path for transmitting an optical signal therein is provided between optical fibers. 2. In the claim 1 of the utility model registration claim,
An optical current transformer for a gas insulated switchgear, characterized in that the insulator has a hollow portion formed therein for transmitting an optical signal, and lenses attached to both ends of the hollow portion of the insulator.