JPS5953019A - Discharge detector - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] The present invention relates to a discharge detection device, and more specifically, it is used to detect discharge occurring inside power equipment, etc., and to monitor accidents such as ground faults occurring in the equipment. This invention relates to a discharge detection device.

Accidents such as ground faults that occur in transformers, circuit breakers, etc. that constitute power equipment can be monitored by detecting arc discharge light (hereinafter referred to as arc light) generated during the accident. Therefore, it would be possible to detect arc light by placing some kind of photodetection element inside the power equipment, but high-voltage TA generators have the disadvantage of being affected by electromagnetic induction, and it is also difficult to place conductors inside the equipment. There is a problem in that the arrangement has an adverse effect on electric field distribution and the like.

Therefore, a method can be considered that uses an insulating optical fiber to guide the arc light to the outside of the device and detect it. but
In this case, the wavelength of the arc light is JOOnLμ~left with a peak at θ0mμ. It is in the region of Q m lt ,
On the other hand, regarding the wavelength dependence of the transmission loss of an optical fiber, as shown in FIG. 1, the transmission loss is extremely large in the wavelength region of arc light. For this reason, in detecting a discharge using an optical fiber, it is extremely difficult to detect the discharge at a location far away from the target object. In addition, the first
The figure is a characteristic diagram related to a silica-based optical fiber.

This invention attempts to resolve the above-mentioned problems to the utmost by converting the arc light into wavelengths and guiding it to the outside of the equipment using an insulating optical fiber, taking into account the transmission loss. The purpose of this invention is to provide a discharge detection device that can monitor abnormalities at a remote location.

The present invention will be explained below with reference to the drawings.

The figure shows a spherical lens 2 coated with a wavelength-selective coating 2a on the optical input end of an optical fiber 1 consisting of a core /q and a cladding /b in an embodiment of the present invention. , are bonded and fixed with adhesive 3. The spherical lens λ is made of a transparent material containing a phosphor, and the wavelength of the arc light l (Vθθ
It has a function of converting light of a wavelength (near SθQmμ to 600mμ) into light of one wavelength (SθQmμ to 600mμ). The other end of the optical fiber 1, the optical output end, is optically coupled to a photodetector (not shown), such as a silicon photodiode.

Next, the operation will be explained.

When arc light is generated inside the power equipment, the arc light is coupled and propagated to the optical fiber by a spherical lens located inside the power equipment. The spherical lens 2 has a light wavelength conversion function as well as a lens function, and by converting the arc light l to a longer wavelength (SOθmμ~t, oomμ), it reduces transmission loss as shown in Figure 1. On the other hand, when the photodetector is a silicon photodiode, its sensitivity is
Since it has a peak near the wavelength of oOmμ, the response output of the photodetector is also increased.

In this way, even if the optical fiber l is extended to a place far away from the power equipment, there is little transmission loss, and light in a highly sensitive wavelength range can be transmitted to the photodetector. can enable discharge detection at

Here, we will discuss the phosphor contained in the spherical lens 2. FIG. 3 shows data on the absorption and emission spectra of SmJ+ ions, where the shaded area is the emission spectrum and the non-shaded area is the absorption spectrum. α indicates the absorption coefficient, and ■ indicates the relative luminescence output. From this figure, Smj+
The ions have an absorption peak at θθmμ, which is almost the same as the peak wavelength of the arc light described above, and have a wavelength of soomμ~60mμ.
It has large emission peaks near 0 mμ and 7θQmμ. This shows that the phosphor containing SmJ+ ions is suitable as a substance that provides the spherical lens 2 with a light wavelength conversion function. Therefore, the spherical lens 21c Sm
``All you need to do is add a phosphor containing ions, and if you add Sm
You can consider using something like xfly.

Furthermore, in FIG. 2, a coating 2a is applied to the spherical lens 2, which transmits the arc light of wavelength 1 and reflects the light of wavelength λ converted by the phosphor 2b-. Therefore, the amount of light transmitted through the optical fiber is increased, and the directivity for arc light is improved, thereby significantly improving detection sensitivity.

The material of the spherical lens 2 may be either glass or resin, or may be a material to which a refractive index gradient lens phosphor is added.

The discharge detection device of the present invention having the above configuration can be installed as appropriate depending on the equipment to be detected such as electric power equipment, etc.
- As an example, the case where it is installed in a gas insulated switchgear is shown in Figs. 1(a) and (b). In the gas-insulated switchgear lθ shown in FIG. Supported by 3.

Central voltage charging part lV- and external metal capacitor 5/! The discharge detection device S of the present invention is intended to monitor short-circuit accidents between R and R. /A is a cable.

As shown in the same figure (b), the left side of the discharge detection device has an optical fiber / passed through the connector /7 provided on the wall of the external metal container /S, and a spherical lens 2 at the tip of the optical fiber l connected to the external metal container /S. It is disposed to protrude into the container /5, and the light output end, which is the extended end of the optical fiber /5, is optically coupled to a photodetector (not shown).

In this way, the discharge detection device left can be easily installed without being affected by the electromagnetic induction of the gas insulated switchgear R, /θ and without involving the electric field distribution inside the gas insulated switchgear lO. Discharge detection can be performed.

FIG. 5 shows another embodiment of the present invention, in which a spherical lens coated with a wavelength-selective coating 2a is attached to an optical fiber l fixed to the optical input end with an adhesive 3, and a protective tube 6 is covered. The same effect can be obtained.

In the above embodiments, a spherical lens unit is used, but the lens unit does not necessarily have to be spherical, and may be any transparent body containing a phosphor. Furthermore, it goes without saying that the device to be detected is not limited to a power-like device.

As described above, the present invention has a configuration in which an optical fiber is appropriately installed in the target device and a medium having an optical wavelength conversion function is provided at the tip of the optical fiber, so the device is simple and inexpensive. It has the effect of providing 9 points of high reliability and reliability.

[Brief explanation of drawings]

Fig. 1 is a characteristic diagram showing the wavelength dependence of transmission loss of an optical fiber, Fig. 2 is a sectional side view of a main part of an embodiment of the present invention, and Fig. 3 is an absorption 1 emission spectrum of the phosphor. , FIG. 9(a) is a side sectional view showing an example of the installation mode, and FIG.
b) is a detailed side sectional view, and the left figure is a side sectional view of a main part of another embodiment of the present invention. /... Optical fiber, Co... Spherical lens (light wavelength converter)
, 2a...film, J...adhesive, G...arc light, 6...
・Protection tube. In each figure, the same reference numerals indicate the same or corresponding parts. Agent Shin Kuzuno - Flame 1 Figure Wavelength (mP) Tail 2 Figure 3 Wavelength seam) Figure 4 (CI)

Claims (3)

[Claims] (1) Arc discharge light generated inside the device to be detected is detected by an optical fiber optically coupled to a photodetector whose light input end faces inside the device to be detected and whose light output end is placed outside the device to be detected. A discharge detection device for detecting a discharge includes an optical wavelength converter doped with a fluorescent substance fixed to the optical input end of the optical fiber, and a coating having wavelength selectivity deposited on the surface of the optical wavelength converter. A discharge detection device characterized by: (2) The discharge detection device according to claim 1, wherein the optical wavelength converter is a spherical lens. (3) The discharge detection device according to claim 1, wherein the coating having wavelength selectivity has a property of transmitting r-recharge light and reflecting fluorescent light.