JPH03188303A - Apparatus for detecting light emitting position - Google Patents

Abstract

PURPOSE:To certainly detect a light emitting position over an entire region by arranging an optical fiber sensor having a fluorescent fiber in an SF6 gaseous atmosphere and opposing the side surface of the fluorescence fiber to a region where the light emitting position must be detected. CONSTITUTION:Optical fiber sensors 7a, 7b, 7c... are constituted by providing fluorescent fibers 9 doped with a fluorescent dye containing BPOT on one ends of transparent optical fibers 8 and providing photodetector 10 on the other ends thereof. The fluorescent fibers 9 of the respective optical fiber sensors 7a, 7b, 7c are arranged so as to be shifted in the longitudinal direction of the optical sensors. When it is assumed that discharge light emission 16 is generated at the position corresponding to the fluorescent fiber 9 of the optical fiber sensor 7b in SF6 gas, the discharge light is incident to the fluorescent fiber 9 from the side surface thereof and fluorescence 9a generated by exciting a phosphor propagates through the transparent optical fiber to be detected by the photodetector 10 and, therefore, the generation position of the discharge light emission 16 is cleared.

Description

Detailed Description of the Invention (Summary) Regarding a device for detecting the position of discharge light emission in SF6 (sulfur hexafluoride) gas using an optical fiber, it is possible to detect weak discharge light emission in SP gas with a simple device. This is a device for detecting the position of light emission in SF or gas, with the aim of accurately detecting light emission at any position, even when the light emission is different. An optical fiber sensor is constructed by providing a fluorescent fiber made of The light incident on any fluorescent fiber excites the phosphor in the fluorescent fiber, causing fluorescence that propagates through the transparent optical fiber and is received by the light-receiving element, causing light emission. configured to detect the presence and location of.

Alternatively, light-receiving elements are provided at both ends of a fluorescent fiber doped with a fluorescent dye containing BBOT, and the presence and position of light emission is detected based on the intensity ratio of light received by each light-receiving element.

(Industrial Field of Application) The present invention relates to a device for detecting the position of discharge light in SPi6 (sulfur hexafluoride) gas using an optical fiber.

(Prior Art) FIG. 7 is a cross-sectional view of a conventional device for detecting the position of discharge light in a gas-insulated switchgear used in substation equipment and the like.

This gas insulated switchgear has a 5F
6 (sulfur hexafluoride) gas is enclosed, and a large number of switches 2 are arranged in the SP atmosphere.

Each switch 2... opens and closes an extremely high voltage current, so deterioration of each part, SF, gas, etc. can cause arc discharge 3 between the switch 2... and case 1, resulting in a ground fault. Or, if there is a foreign substance 4 in the SPb gas, the foreign substance 4 may cause partial light emission 5. When such discharge occurs, it is necessary to detect it and take measures such as repair.

Conventionally, methods have been used to do this, such as drilling a hole in the case 1 and smelling the inside, and if there is a burning smell, it is determined that an electrical discharge has occurred, or the sound and vibration caused by the electrical discharge are detected. was.

[Problem to be solved by the invention]

However, the method of drilling a hole in the case l and smelling the smell is laborious, and is especially fatal in that it cannot be detected immediately when discharge occurs.

Although methods for detecting discharge sounds and vibrations may be used to detect strong discharges, it is difficult to accurately detect weak discharges. In particular, it is extremely difficult to accurately detect the location where the discharge occurs.

On the other hand, many optical fibers 6 and 6 are connected from the side of the case l.
It has been proposed to detect the light emitting position by inserting an optical fiber and making the tip of the optical fiber face the switch 2. However, in this case, the optical fiber 6...
Since light can only enter from the tip, if a discharge occurs between adjacent optical fibers 6 to 6, it cannot be detected. To ensure that all discharge luminescence can be detected,
As shown in 6a, it is necessary to arrange the optical fibers closely over the entire length of the row of each switch 2...
It lacks feasibility. In addition, a large number of optical fibers 6...
Implementation toward the center of case l is difficult and requires a large space. A large number of condensing lenses and light-receiving elements are required to be provided at the end of the optical fiber sensor, making it impractical.

The technical problem of the present invention is to eliminate such problems and solve the problem of SF
The object of the present invention is to enable accurate detection of discharge light emission in 6 gases, even weak light emission, at any position using a simple device.

[Means to solve the problem]

FIGS. 1(a) and 1(b) are diagrams illustrating the basic principle of the light emitting position detecting device according to the present invention. (a) uses a plurality of optical fiber sensors; 6(b) uses - optical fiber sensors.

The means of (a) includes a plurality of optical fiber sensors 7a, 7
b.

7c... are arranged in parallel. Each optical fiber sensor 7a, 7b, 7c... has a BBOT (2,5-bis (5-t
ert-2-butylbenzoxazoyl)
A fluorescent fiber 9 doped with a fluorescent dye containing thiophene is provided, and a light receiving element 10 is provided at the other end.

The fluorescent fibers 9 of each optical fiber sensor 7a, 7b, 7C... are arranged even in the longitudinal direction of the optical fiber sensor. Each fluorescent fiber 9 is arranged so that its side surface faces a position where light emission is expected to occur in the SF6 gas.

In the means (b), the side surface of one optical fiber sensor 11 is arranged so as to face the position where light emission is expected to occur in the SF6 gas. This optical fiber sensor 11 has a configuration in which light receiving elements 13 and 14 are provided at both ends of a fluorescent fiber 12 doped with a fluorescent dye containing BRAT. Both light receiving elements 13.14 are connected to a comparison circuit 15, and the light emitting position is detected by comparing the output values of both light receiving elements 13.14.

[Effect]

A fluorescent fiber doped with a fluorescent dye containing BBOT, that is, a fluorescent fiber doped with B[lOT or a mixture of BBOT and another fluorescent dye, is SF, 6
Since it reacts efficiently to luminescence in gases, it has excellent sensitivity and can detect even weak luminescence.

Furthermore, since the fluorescent fiber also generates fluorescence due to light incident from its side, by arranging the side of the fluorescent fiber so as to face the position where light emission is expected, light emission can be detected over a wide range.

In other words, by increasing the length of the fluorescent fiber 9 portion of each optical fiber sensor in Figure 6 (a1), it is possible to detect light emission at any position as long as it is within the area of the length.

Therefore, if discharge light emission 16 in SF or gas occurs at a position facing the side surface of the fluorescent fiber 9 of the optical fiber sensor 7b in the middle, it will enter the fluorescent fiber 9 from the side surface. The incident light excites the phosphor in the fluorescent fiber 9 to generate fluorescence 9a, which propagates through the transparent optical fiber 8 and is received by the light receiving element IO.

As a result, by detecting that the light-receiving element of the optical fiber sensor 7b has received light from the output signal of the light-receiving element, the light emitting position is determined to be a position facing the fluorescent fiber 9 of the middle optical fiber sensor 7b. I understand.

In this way, by shifting the position of the fluorescent fiber of each optical fiber sensor by the length L of the fluorescent fiber, it is possible to detect light emission in an area of length 3L using the three optical fiber sensors. In addition, when light is emitted in a 3L length region, it is always incident on the side of one of the fluorescent fibers 9..., so unlike when using conventional optical fibers, the light is emitted at a position opposite to the light emitting position. The absence of an optical fiber end does not result in undetectability.

If the length of each fluorescent fiber 9 is made smaller and the sliding pitch P is made smaller, the number of optical fiber sensors will increase, but the resolution can be increased and the light emitting position can be detected with higher accuracy. becomes possible.

When the light receiving elements 13 and 14 are provided at both ends of one fluorescent fiber 12 and the side surface of the fluorescent fiber 12 is opposed to the light emitting position as shown in FIG. 17 occurs, the fluorescent fiber 12
Inside, a phosphor at a position facing the light emission 17 emits fluorescence. The distance l from the incident position to the right light receiving element 14 is greater than the distance 11 from the incident position of the discharge light 17 to the side surface of the fluorescent fiber 12 to the left light receiving element 13! Since 1l12 is small, the right light receiving element 14
The transmission loss until reaching the left photodetector 14 is greater than the transmission loss until reaching the left light receiving element 14. Therefore, by comparing the amount of light received by both light receiving elements 13 and 14 in the comparison circuit 15, the distance from each light receiving element 13, 14 to the discharge light incident position is detected, and the position of the discharge light emission 17 is detected. be able to.

In this case, a circuit 15 for comparing the output values of the detection signals of both light receiving elements 13 and 14 is required, but since one optical fiber sensor is sufficient, the configuration of the light emitting position detection device is extremely simplified. It requires a small installation space and is particularly effective when installed in a narrow space inside a gas-insulated switchgear.

〔Example〕

Next, how the light emitting position detecting device according to the present invention is actually implemented will be explained using an example. ・Figure 2 shows a BBO
FIG. 3 is a diagram illustrating a fluorescence conversion effect in a fluorescent fiber doped with T. 18 is the core of the fluorescent fiber, which is made of polycarbonate doped with BBOT. The outer periphery of this core 18 is covered with a cladding 19. The outer diameter of the cladding 19 is approximately 11I11φ.

Assuming that the refractive index of the core 18 is nl and the refractive index of the cladding 19 is 12, nl>n2. Further, if the wavelength of the incident light 20 from the side surface of the fluorescent fiber is λl, and the wavelength of the fluorescence 21 that is totally reflected and propagated in the core 18 is λ2,
The relationship is λ1 x λ2.

The core 18 is made of polycarbonate with 0.0% BBOT.
(A material doped with 12 wt% was used. Also, cladding 1
In No. 9, a mixture of polymethyl methacrylate and polyvinylidene fluoride was used.

Assuming that the particles of BBOT phosphor doped into polycarbonate are 22, the BBOT phosphor particles 22 have the following properties:
When incident light 2o is irradiated from the side of the fluorescent fiber, B
The BOT phosphor particles 22 emit fluorescence.

When this fluorescence is incident on the cladding 19, the critical angle θ. The component with a larger incident angle repeats total reflection within the core 18, as shown by 21, and propagates to the end. Components whose incident angle is smaller than the critical angle θ pass through the cladding 19 from the core 18 and escape to the outside.

Therefore, when the incident light 20 enters from the side surface of the fluorescent fiber, the BBOT phosphor particles 22 efficiently emit fluorescence, and a larger amount of fluorescence propagates as totally reflected light 21 and can be emitted from the end. is necessary for detecting weak luminescence in SF6 gas.

FIG. 3 is a diagram showing the emission spectrum of spark discharge in SF gas at a gas pressure of 1520 Torr.

As is clear from this figure, the inventors of the present invention have confirmed that gas discharge (spark discharge) light in SF and gas has a strong emission intensity in the wavelength 4 (10 to 450 nm) region.

In addition, in order to receive the discharge light in SF6 gas and emit fluorescence, it is necessary to emit fluorescence at 4 (10 to 45
It is necessary to realize a fluorescent fiber that is sensitive to light in the 0 nm wavelength range in order to be able to efficiently detect even weak light emission.

FIG. 4 is a diagram showing the fluorescence spectrum of the BBOT dye doped into polycarbonate, where the horizontal axis is the wavelength and the vertical axis is the fluorescence intensity. This fluorescence spectrum was obtained by measuring the light emitted from the end face when halogen light was irradiated onto the side surface of a BBOT-doped fluorescent fiber, and the fluorescence intensity peaked at a wavelength around 45 on-. There is.

FIG. 5 is a diagram showing a light absorption spectrum of 8801 dye doped into polycarbonate, where the horizontal axis is the wavelength and the vertical axis is the absorption rate. According to the principle of luminescence, fluorescence efficiency increases when excited with light of the same wavelength as the absorption peak. As is clear from this figure, the absorption peak wavelength is
440nn+, which is the wavelength range of 4(1
It is included in the region of 0 to 450 nts.

From the above results, the fluorescent fiber made by doping polycarbonate with BBOT is suitable for the wavelength range 4 (10 to 450 nm), which is the wavelength range where the intensity of gas discharge light in SF and gas is high.
It has excellent fluorescence conversion efficiency for light, and can emit strong fluorescence.

Table, l is 4 on the side of the BBOT-doped fluorescent fiber.
This is a measurement result comparing the fluorescence conversion efficiency η in the fiber axis direction when irradiated with 0.05 nm light with that of perylene dye.

Table 1 As is clear from the measurement results shown in Table ■, BBOT
The fluorescent fiber doped with perylene dye has an order of magnitude better fluorescence conversion efficiency than the fluorescent fiber doped with perylene dye.

As described above, in the case of a fluorescent fiber made of polycarbonate doped with a BBOT dye, in the wavelength range where the intensity of gas discharge light in SF6 gas is high, the excitation light absorption rate for incident light is high and the fluorescence conversion efficiency is excellent. ing. Therefore, even weak discharge light emission in SF or gas can be reliably detected.

The fluorescent dye doped into the core material such as polycarbonate is not limited to BBOT, and a mixture of BBOT and other fluorescent dyes, such as perylene dyes, may be doped.

Table 2 shows the wavelength range of light to which commercially available green, yellow, and red perylene fluorescent dyes are sensitive.

The circle mark indicates that fluorescence is generated.

Perylene dyes are also sensitive to light in the wavelength range 4 (10 to 450 nm), where the intensity of gas discharge light in SF6 gas is high. By using it together with BBOT, the sensitivity to light in this region can be increased. is possible.

Table 2 The core material of the fluorescent fiber is not limited to polycarbonate, and other transparent resins such as styrene, PMMA, etc. may be used.

FIG. 6 is a sectional view showing an example in which the light emitting position detection device of the present invention is implemented in a gas insulated switchgear. In this figure, a
is a light emitting position detection device using a plurality of optical fiber sensors shown in FIG. 1(a), and b is a light emitting position detection device shown in FIG. 1(b).
This is a light emitting position detection device using a single optical fiber sensor as shown in FIG.

The light emitting position detection device of the present invention is housed in a case l which is filled with SF and gas and also houses a high-pressure switch 2 . The light emitting position detection device a is in case l.
Inside, a bundle 7 of a plurality of optical fiber sensors 7a, 7b, . . . shown in FIG. An output signal line 25 is led out from 24. In addition,
Using 0 optical fiber sensors, each fluorescent fiber section is arranged at a predetermined pitch L in a detection area of nL so as to prevent the occurrence of spots where no fluorescent fiber section exists.
They are placed off-center.

Therefore, when a discharge occurs in the region of nL, the discharge light enters from the side of the fluorescent fiber of the optical fiber sensor, is converted into fluorescence, and is converted into an electric signal by the light receiving element, and is sent from the output signal line 25. Output. Then, the light emitting position is detected depending on which output signal line the output signal is generated from.

The light emitting position detection device is located in the case 1, and the pipe 2
6, the single optical fiber sensor 11 shown in FIG. Signal lines 29 and 30 are connected to the comparison circuit 15.

Therefore, in the comparison circuit 15, the optical fiber sensor 1
By comparing the intensities of the detection signals of the light receiving elements at both ends of 1, the detection area! The position where discharge light is generated can be detected.

Although an example has been shown in which the light emitting position detection device of the present invention is implemented in a gas insulated switchgear, it goes without saying that it can be applied to devices other than gas insulated switchgears as long as they cause discharge in SF6 gas.

〔Effect of the invention〕

As described above, according to the light emission position detection device of the present invention, an optical fiber sensor having a fluorescent fiber is disposed in an SF or gas atmosphere, and the side surface of the fluorescent fiber is made to face an area where light emission position detection is required. This allows the light emitting position to be detected reliably over the entire area.

In particular, since the fluorescent fiber is doped with a fluorescent dye containing BBOT, it can efficiently detect the position of discharge light in SF6 gas, reliably detect even weak light emission, and provide highly reliable light emission position detection. can be done.

Since the optical fiber sensor can be arranged so that the emitted light enters from the side of the fluorescent fiber, the optical fiber sensor can be installed parallel to the longitudinal direction of the emitting position detection area, making the configuration of the emitting position detection device simple and requiring a small installation space. Suitable for installation in confined spaces, such as in small spaces or gas-insulated switchgear.

[Brief explanation of drawings]

FIGS. 1(a) and 1(bl) are side views explaining the basic principle of the light emitting position detection device according to the present invention; FIGS. Figure 3 shows the emission spectrum of spark discharge in a gas with a gas pressure of 1520 TorrO5F. Figure 4 shows the fluorescence spectrum of BBOT dye doped in polycarbonate. Figure 5 shows the emission spectrum of BBOT doped in polycarbonate. A diagram showing the light absorption spectrum of a dye, FIG. 6 is a cross-sectional view showing an example in which the light emitting position detection device of the present invention is applied to a gas insulated switchgear, and FIG. 7 is a diagram showing the detection of a discharge position in a gas insulated switchgear. 1 is a sectional view showing a conventional device. In the figure, ■ indicates a metal case, 2... indicates a switch, and 3.
5 is discharge light, 7a, 7b, 7c, 11 is an optical fiber sensor, 7 is a bundle of a plurality of optical fiber sensors, 8 is a transparent optical fiber, 9.12 is a fluorescent fiber (part), 9a is fluorescent light, 10. 13.14 is a light receiving element, 15 is a comparison circuit, 16
．． 17 is a discharge light, 18 is a core, 19 is a cladding, and 22 is a phosphor.

Claims (1)

[Claims] 1. A device for detecting the position of light emission in SF_6 (sulfur hexafluoride) gas, comprising a fluorescent fiber doped with a fluorescent dye containing BBOT at one end of a transparent optical fiber (8). (9) and a light-receiving element (10) at the other end, an optical fiber sensor is constructed. The sensors are arranged to be shifted in the longitudinal direction, and the light that enters any fluorescent fiber excites the fluorescent material in the fluorescent fiber, causing fluorescence that propagates through the transparent optical fiber (8) and reaches the light receiving element (8). 10) A light emission position detection device characterized in that it is configured to detect the presence of light emission and its position by receiving light at the light emission point. 2. A device for detecting the position of light emission in SF_6 (sulfur hexafluoride) gas, in which light-receiving elements (13) and (14) are provided at both ends of a fluorescent fiber (12) doped with a fluorescent dye containing BBOT. The light incident on the fluorescent fiber (12) from the side excites the phosphor in the fluorescent fiber (12), causing the fluorescence to propagate through the fluorescent fiber (12) and reach the light-receiving elements ( 13) Light emitting position detection characterized in that the light is received by (14), and the presence of light emitted and its position are detected based on the intensity ratio of the light received by the respective light receiving elements (13) and (14). Device.