JP2766924B2 - Optical current transformer for gas insulated switchgear - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an optical current transformer for a gas insulated switchgear. [Prior art] Conventionally, this type of optical current transformer for a gas insulated switchgear connects an optical fiber between a detecting unit provided on a charging unit side and a light emitting unit and a light receiving unit provided on a ground side. Transmits optical signals. A specific example is shown in FIG. FIG. 1 shows a configuration example of an all-glass optical current transformer (hereinafter, referred to as an optical CT). Light emitting diode
The signal from 21 is guided by an optical fiber 22 to an optical CT detection unit 24 installed around a high-voltage conductor 23. Optical CT detector
The optical signal passing through the glass prism 25 and the polarizing prism 26 in 24 is guided to the photodiode 27 by the optical fiber 22, where it is converted from the optical signal into an electric signal. Here, a light emitting unit constituted by the light emitting diode 21 and a light receiving unit constituted by the photodiode 27 are:
On the ground side, the optical CT detector is installed on the high voltage conductor side,
Electrical insulation between the two is provided by an optical fiber. Now, when this optical CT is incorporated into a gas insulated switchgear (hereinafter referred to as GIS), a characteristic of GIS is that a high dielectric strength SF ₆ (sulfur hexafluoride) gas is sealed, and a high voltage is applied. Since the insulation distance between the ground side and the ground side is short, the optical fiber generally applies a voltage several times larger than that in the aerial system per unit length. In addition, the dielectric constant of the optical fiber is 5-10
Because it is twice as large, the concentration of the electric field occurs and the insulation performance of the GIS is reduced. For this reason, a method of transmitting an optical signal to a gas space has been studied. This example is shown in FIG. FIG. 5 is an example of gas space transmission of the all-glass optical CT of FIG. The optical signal from the light emitting diode 21 is guided by an optical fiber 22 to a lens 28, and the optical signal incident on the insulating gas by the lens 28 propagates through the gas, and is set on a high voltage side. It is led to the optical fiber 22 by 28 '. Optical CT detector 24
The optical signal passed through is guided to the lens 28 'by the optical fiber 22, and the optical signal incident on the insulating gas by the lens 28' propagates through the gas again and is set on the ground side. The light is guided to the optical fiber 22 by the lens 28. The optical signal guided to the photodiode 27 by the optical fiber 22 is
Here, the light signal is converted into an electric signal. With this configuration, since the optical signal transmission between the high voltage side and the ground side is performed between the gas chambers, there is no lowering of the insulation performance unlike the optical fiber system. However, since the optical signal is transmitted through the gas space in the gas circuit breaker (GCB), the light emission phenomenon inside the GCB (arc light at the time of current interruption, preceding arc light at the time of injection etc.) In this spatial transmission system, there is a problem in terms of the accuracy and signal stability of the optical signal because it acts as disturbance noise. For this reason, as shown in FIG. 6, a cylindrical light shielding insulator 5 is disposed in a portion located in the gas space between the lenses 28 and 28 ', and the lens 28 provided at one end is provided. The optical signal from the optical fiber 22 enters the gas space in the insulator 5 and is condensed by the lens 28 at the other end to send the optical signal to the optical fiber 22 (see FIG. 60). No. 159381). [Problems to be Solved by the Invention] However, the above-mentioned optical CT for a gas insulated switchgear is generated when an optical signal gas space transmission unit, that is, a method for filling the SF ₆ gas inside the insulator 5 and when current is interrupted. has failed has been consideration for protection of the lens 28, 28 'from the SF ₆ decomposition gas. Therefore, the surface of the lens 28, 28 'are damaged by SF ₆ decomposition gas generated during current interruption, a problem that the optical CT characteristic is changed by the optical signal transmission efficiency decrease occurs. Therefore, the present invention has been made based on such circumstances, and it is possible to shield disturbance light at the time of current interruption to the optical signal space transmission unit, and to maintain the filling of high purity SF ₆ gas. can be, it is an object to provide a gas insulated switchgear optical CT which eliminates damage to the lens by SF ₆ decomposition gas. [Means for Solving the Problems] In order to achieve such an object, the present invention provides a method of converting a detection unit to a high voltage side and converting an optical signal serving as an input / output signal of the detection unit into an electric signal. A gas transformer for a gas insulated switchgear in which an SF ₆ gas space of an optical transmission unit interposed between a lens between the detection unit and the converter is optically shielded with an insulator. the SF ₆ gas inlet is provided, providing a passage leading from the gas inlet to within SF ₆ gas space of the optical transmission unit in said insulator, in the middle of the passage, SF ₆
A cracked gas adsorption chamber filled with a gas cracked gas adsorbent is provided, and the passage has at least two bent portions bent at right angles to the traveling direction. [Operation] As described above, if the insulating material is provided with the SF ₆ gas inlet, and the SF ₆ gas flows in through the SF ₆ decomposition gas adsorbent,
The SF ₆ gas space in the insulator is filled with only SF ₆ gas without SF ₆ decomposition gas remaining. Therefore, damage to the lens exposed to the SF ₆ gas atmosphere can be prevented. In addition, the passage from the SF ₆ gas inlet to the SF ₆ gas space in the insulator is prevented from entering the light from the gas inlet by a bent portion, and the light shielding function of the insulator is maintained. You. Embodiment FIG. 1 is a view showing one embodiment of a schematic partial configuration of a gas circuit breaker to which the present invention is applied. As shown in the figure, inside the jacket, there is a blocking part 2, a stator-side conductor 3 at the upper part, and a mover-side conductor 4 at the lower part. Optical CT detectors 7 are arranged around the high-voltage conductors 7 'of the stator-side conductor 3 and the mover-side conductor 4, respectively. Also,
An insulator 5 is disposed below the jacket, and the insulator 5
Lenses are disposed on the upper and lower sides of the optical CT, and the upper one of the lenses is connected to the optical CT detection unit 7 via an optical fiber. The lower lens is connected to a light emitting diode and a photodiode via an optical fiber. The details of the insulator 5 are shown in FIG.
(B) and (c). 2A is a top view, FIG. 2B is a sectional view, and FIG. 2C is a bottom view. In the figure, the cylindrical insulator 5 is made of an epoxy resin or a reinforced plastic material using glass fiber as a reinforcing material. Lids 5 ′ are adhered to both ends of the insulator 5, and lenses 28, 28 are fixed to each of the insulators 5 with the same optical axis parallel to the central axis of the insulator 5. In each of the lenses 28, 28, the surface inside the insulator 5 is exposed in the insulator 5, the opposite solid surface is shielded from the atmosphere outside the insulator 5, and one of the lenses is interposed through the optical fiber 22. The other is connected to a not-shown optical CT detection unit, and the other is connected to a not-shown light-emitting diode and photodiode. An SF ₆ gas inlet A is provided on one side of the lid 5 '. FIGS. 3 (a) and 3 (b) show details of the SF ₆ gas inlet A. FIG. FIG. 3A is a top view, and FIG. 3B is a cross-sectional view. In FIG. 2B, there is a gas charging port 8, which is connected to the SF ₆ decomposition gas adsorbent chamber 30. The SF ₆ decomposed gas adsorbent chamber 30 is filled with the SF ₆ decomposed gas adsorbent 6, and specific examples thereof include activated alumina and synthetic zeolite. The SF ₆ decomposition gas adsorbent chamber 30 has two bent portions in a direction perpendicular to the gas filling port 8 and is separate from the SF ₆ decomposition gas adsorbent chamber 30 and above the adsorbent chamber 30. Is provided with a gas route 9 which leads to the decomposition gas adsorbent chamber 31 located at. Again SF ₆ decomposition gas adsorbent 6 is filled in the decomposition gas adsorbent chamber 31. The cracked gas adsorbent chamber 31 is provided with a passage 12 communicating with the insulator 5. According to the optical CT for the gas insulated switchgear thus configured, the SF ₆ gas is injected into the insulator 5 from the gas inlet 8 through the two SF ₆ decomposition gas adsorbent chambers 30 and 31. Is done.
Since the SF ₆ decomposition gas adsorbent chambers 30 and 31 are filled with an SF ₆ decomposition gas adsorbent such as activated alumina or synthetic zeolite, SF ₆ decomposition gas is mixed into the insulator 5. Therefore, damage to the lens 28 can be prevented. Further, since the gas route 9 including the SF ₆ decomposition gas adsorbent chambers 30 and 31 has a bent path, light during a light emission phenomenon inside the GCB does not enter the insulator 5. Thus, the accuracy of the optical signal in the insulator 5 and the stability of the signal can be reliably obtained. In the above embodiments, wherein at gas route 9 are those that are configured with a three perpendicular bent portion is not limited to this number, insulated from the SF ₆ gas in the gas seal port 8 It is sufficient if a bent portion sufficient for light shielding to the gas space in the object 5 is formed. [Effects of the Invention] As is clear from the above description, according to the optical current transformer for a gas insulated switchgear of the present invention, it is needless to say that disturbance light during current interruption to the optical signal space transmission unit can be shielded. In addition, it is possible to maintain the filling of high-purity SF ₆ gas and to eliminate lens damage due to SF ₆ decomposition gas.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view showing one embodiment of a schematic partial configuration of a gas insulated switchgear to which the present invention is applied, and FIGS. 2 (a), (b),
2 (c) is a configuration diagram showing details of the insulator shown in FIG. 1, wherein FIG. 2 (a) is a top view, FIG. 2 (b) is a cross-sectional view, FIG. 2 (c) is a bottom view, and FIG. 3 (a) and 3 (b) are structural diagrams showing details of the SF ₆ gas inlet attached to the insulator.
3 (a) is a top view, FIG. 3 (b) is a sectional view, and FIGS. 4 to 6 are explanatory views showing an example of a conventional light CT for a gas insulated switchgear. 1 ... GCB tank, 2 ... Blocking part, 3 ... Stator side conductor, 4 ... Movator side conductor, 5 ... Insulator, 6 ... Adsorbent, 7 ... Optical CT, 8 ... Gas Enclosure port, 9: gas route, 12: gas space.

Claims (1)

(57) [Claims] A detecting unit is provided on the high voltage side, a converter for converting an optical signal serving as an input / output signal of the detecting unit to an electric signal is provided on the ground side, and an optical transmission unit sandwiched between a lens between the detecting unit and the converter is provided.
In the SF ₆ gas space gas insulated switchgear for the optical current transformer which is light shielded with an insulator, the insulating material provided SF ₆ gas inlet, SF of the optical transmission unit in said insulator from the gas inlet port ₆ A passage leading to the gas space is provided, and a cracked gas adsorption chamber filled with SF ₆ gas cracked gas adsorbent is provided in the middle of this passage, and the passage is bent at a right angle to the traveling direction. The passage has two bent portions, and the passage has a parallel hole, which is two parallel holes, and an orthogonal hole, which is one hole orthogonal to one of the parallel holes and electrically connected to the other hole. And three bolts respectively sealing the parallel hole and the orthogonal hole.