JP2013105660A - Arc discharge monitoring apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To certainly detect arc discharge 16 at a place where monitoring of a DC high voltage breaker 12 is required to prevent erroneous detection by disturbance light 56.SOLUTION: An arc discharge monitoring device includes: an optical sensor 18 which receives light to be generated by arc discharge 16 to output a detection signal; a display device 20 which performs alarm display by the detection signal to be output by the optical sensor 18; and an optical guide 28 obtained by arranging a light receiving end 24 in an area where the arc discharge 16 is generated, and connecting the other end 26 to the optical sensor 18. A condenser lens system 40 which sets, when a closed loop 30 surrounding an area where the arc discharge 16 is generated is drawn if being viewed from the light receiving end 24 of the optical guide 28, a cone 36 obtained by using a circle 32 or a polygon 34 circumscribing the closed loop 30 as the bottom face and using the light receiving end 24 as the apex, and receives only light within a range that the area where the arc discharge 16 is generated can be seen through from the light receiving end 24 at a state of being surrounded by the side face 38 of the cone 36 is attached to the light receiving end 24 of the optical guide 28.

Description

  The present invention relates to an arc discharge monitoring apparatus for monitoring arc discharge generated in a DC high voltage circuit breaker.

  In substations that supply power to electric railways, DC high-voltage circuit breakers are used to protect DC power transmission circuits, DC power equipment, and the like. An arc generated when a large direct current is interrupted melts the contacts and ignites surrounding insulators. In a DC high voltage circuit breaker, when an arc is generated, it is difficult to extinguish automatically, and the arc must be forcibly extinguished. If left unattended, there is a risk of fire in electrical equipment. Therefore, a circuit for electrically detecting the generation of an arc and a device for optically detecting the generated arc with an optical fiber have been developed (see Patent Document 1).

Japanese Patent Application Laid-Open No. 6-243763

The known prior art has the following problems to be solved.
For the operation of electric railways, DC high voltage circuit breakers are used in various places. There are closed circuit breakers housed in sealed containers and open circuit breakers with exposed contacts. In addition, there are cases where the arc is not always generated in the vicinity of the contact. Moreover, arc discharge at a location far from the contact is more likely to cause a fire than around the contact. In the known optical detection method, it is difficult to detect all arc discharges without leakage, and there is a problem that erroneous detection occurs due to ambient light.
In order to solve the above problems, the present invention has an object to provide an arc discharge monitoring device that detects all arc discharges in a place where monitoring is required without omission and prevents erroneous detection due to ambient light. To do.

The following configurations are means for solving the above-described problems.
<Configuration 1>
An optical sensor that receives light generated by arc discharge and outputs a detection signal, a display device that displays an alarm by the detection signal output by the optical sensor, and a light receiving end disposed in the region where the arc discharge occurs, When a light guide having the other end connected to the light sensor and a closed loop surrounding the region where the arc discharge is generated as viewed from the light receiving end side of the light guide, a circle or a polygon circumscribing the closed loop is formed on the bottom surface. A cone having the light receiving end as a vertex is set, and only light within a range in which the arc discharge can be seen from the light receiving end in a state surrounded by the side surface of the cone is received. An arc discharge monitoring apparatus, wherein a condenser lens system is attached to the light receiving end of the light guide.

<Configuration 2>
The arc discharge monitoring apparatus according to Configuration 1, wherein an optical filter that allows ultraviolet light to pass through and blocks other light is incorporated into a part of the condenser lens system.

<Configuration 3>
In the arc discharge monitoring apparatus according to Configuration 1 or 2, the condensing lens system is a hood formed of a side surface of a cone or a part of a polygonal pyramid having a light receiving end of the light guide as a vertex, and a wavelength to be detected. And an optical system that converts light incident through the hood into light parallel to the optical axis of the light guide at the light receiving end. Monitoring device.

<Configuration 4>
In the arc discharge monitoring apparatus according to Configuration 3, the light guide is one or a plurality of optical fibers having a core and a clad, and is cut at a light receiving end at a plane perpendicular to the optical axis. An arc discharge monitoring device characterized by

<Effect of Configuration 1>
Since light in the area where arc discharge occurs is received within the range surrounded by the cone and the side surface of the polygonal pyramid with the light receiving end of the light guide as the apex, all arc discharges are generated without being disturbed by disturbance light. It can be detected reliably.
<Effect of Configuration 2>
If only the ultraviolet light is received from the light receiving end, the arc discharge having a large ultraviolet light component can be detected without being distracted by other external light.
<Effect of Configuration 4>
From the end face of the optical fiber cut along a plane perpendicular to the optical axis, light is input only within the range of the aperture angle. Therefore, only the light guided by the above optical system can be accepted and the disturbance light can be blocked.

(A) is an external appearance perspective view of the circuit breaker 12, (b) is a schematic explanatory drawing of the arc discharge monitoring apparatus 10. FIG. 4 is a characteristic explanatory diagram of a condenser lens system 40. FIG. 3 is a longitudinal sectional view showing a specific structural example of a condenser lens system 40. FIG. It is explanatory drawing of the optical sensor 18 which connected the end of the optical fiber 54, and a subsequent apparatus.

  Hereinafter, embodiments of the present invention will be described in detail for each example.

FIG. 1A is an external perspective view of the circuit breaker 12, and FIG. 1B is a schematic explanatory diagram of the arc discharge monitoring device 10.
For example, the arc discharge monitoring device 10 is attached to a circuit breaker 12 as shown in FIG. Inside the circuit breaker 12, a contact 14 for interrupting a DC high-voltage current is disposed, and is electrically shielded by a shielding plate 15, for example. When the contact 14 is opened and closed, for example, an arc discharge 16 may occur between the contact 14 and the shielding plate 15. The arc discharge monitoring device 10 detects this.

  The arc discharge monitoring device 10 includes an optical sensor 18 that receives light generated by the arc discharge 16 and outputs a detection signal, and a display device 20 that displays an alarm based on the detection signal output from the optical sensor 18. Light generated by the arc discharge 16 is input to the optical sensor 18 through the light guide 28. Since the light generated by the arc discharge 16 has many ultraviolet light components, it is preferable that the optical sensor 18 has high sensitivity to light close to the ultraviolet region. As the light guide 28, for example, a bundle of one or more optical fibers made of quartz glass is suitable.

  In the light guide 28, the light receiving end 24 is disposed in a region where the arc discharge 16 is generated, and the other end 26 is connected to the optical sensor 18. A condenser lens system 40 is attached to the light receiving end 24 of the light guide 28.

FIG. 2 is a characteristic explanatory diagram of the condenser lens system 40.
The condenser lens system 40 is designed as follows. First, as viewed from the light receiving end 24 side of the light guide 28 shown in FIG. 1, a closed loop 30 surrounding the region where the arc discharge 16 is generated is drawn. Next, as shown in FIG. 2A, a circle 32 circumscribing the closed loop 30 is drawn. A cone 36 (here, a cone) having the circle 32 as the bottom surface and the light receiving end 24 as a vertex 37 is set.

  In a state surrounded by the side surface 38 of the cone 36, only light within a range in which the region where the arc discharge 16 is generated can be seen from the light receiving end 24 is received. An example of the configuration will be described with reference to FIG. In the case where the closed loop 30 surrounding the region where the arc discharge 16 is generated is a polygon, for example, as shown in FIG. 2B, a cone 36 having a polygon 34 as a bottom surface and a light receiving end 24 as a vertex 37. Should be set. In FIG. 2B, the region 22 where the arc discharge occurs forms a polygon 34, and the cone 36 is set with the polygon 34 as a closed loop 30. Therefore, the reference numerals of the corresponding parts in the figure are 22 (34) and (30).

  That is, as shown in FIG. 1, light in a region where the arc discharge 16 is generated is received in a range surrounded by the side surface 38 of the cone 36 having the light receiving end 24 of the light guide 28 as the apex 37. Light incident from other places is blocked by the condenser lens system 40. As a result, the generation of the arc discharge 16 can be reliably detected without being disturbed by the disturbance light 56.

  As described above, the bottom surface of the cone 36 may be elliptical or rectangular. Moreover, it may be not a regular polygon but a deformed polygon with irregularities. The disturbance light 56 is blocked as much as possible, and the entire area where the arc discharge 16 may be generated is set as a monitoring target.

FIG. 3 is a longitudinal sectional view showing a specific structural example of the condenser lens system 40.
The condenser lens system 40 is a combination of a hood 44, an optical system 48, and an optical filter 42. The light receiving end 24 of the optical fiber 54 is fixed to the optical filter 42 side. The optical fiber 54 is, for example, a plastic optical fiber having a core 50 and a clad 52. That is, in this embodiment, the optical fiber 54 is used for the light guide 28.

  The hood 44 is made of, for example, metal or plastic, and is a hood 44 including a side surface 38 that is a part of a cone having the light receiving end 24 of the optical fiber 54 as a vertex 37. The hood 44 has an inner wall 46 that does not reflect light having a wavelength to be detected. For example, this characteristic can be realized if the hood 44 is formed of a black plastic molding.

  The optical system 48 has a function of converting light incident through the hood 44 at the light receiving end 24 of the optical fiber 54 into light parallel to the optical axis of the optical fiber 54, and is configured by, for example, a concave lens. A prism or a collimator lens can also be used. Thereby, all the light incident through the hood 44 can be introduced into the core 50 of the optical fiber 54.

  The end face of the optical fiber 54 does not require special processing. One or a plurality of optical fibers 54 having the core 50 and the clad 52 may be cut as they are at the light receiving end 24 at a plane perpendicular to the optical axis. Even with an optical fiber having a small aperture angle, all incident light can be received by the core 50. At the same time, only the light guided by the optical system 48 can be accepted and the disturbance light 56 can be blocked.

  The optical filter 42 is incorporated in a part of the condenser lens system 40. As the optical filter 42, an optical filter that transmits ultraviolet light and blocks other light is used. The light generated by the arc discharge 16 contains a lot of ultraviolet light components. If only ultraviolet light is received from the light receiving end 24, even if light enters due to a cause other than the arc discharge 16, the light is blocked by the optical filter 42, so that the detection accuracy of the arc discharge 16 is further improved.

FIG. 4 is an explanatory diagram of the optical sensor 18 to which one end of the optical fiber 54 is connected and a subsequent device.
One end of the optical fiber 54 is fixed to the optical sensor 18. When the light sensor 18 detects incident light, a detection signal proportional to the intensity of the incident light is output from the terminal. This is amplified by the amplifier circuit 58.

  The output of the amplifier circuit 58 is input to the determination circuit 60. The determination circuit 60 drives the switch circuit 62 to turn on the switch when the output of the amplifier circuit 58 is equal to or higher than a certain level. Accordingly, for example, the display device 20 configured by Patlite (registered trademark) is driven to report that an arc is generated. The display device 20 may be a buzzer, for example. Further, it may be a transmitter that transmits an alarm signal to a remote monitoring center.

  With the above configuration, the arc discharge monitoring apparatus of the present invention can reliably detect the light caused by the arc discharge generated in the circuit breaker 12 without being disturbed by disturbance light, and can notify a monitor or the like. Therefore, it is possible to prevent a fire or the like caused by arc discharge.

DESCRIPTION OF SYMBOLS 10 Arc discharge monitoring device 12 Circuit breaker 14 Contact 15 Shield plate 16 Arc discharge 18 Optical sensor 20 Display device 22 Area where arc discharge occurs 24 Light receiving end 26 Other end 28 Light guide 30 Closed loop 32 Circle 34 Polygon 36 Cone 37 Top 38 Side 40 Condensing lens system 42 Optical filter 44 Hood 46 Inner wall 48 Optical system 50 Core 52 Clad 54 Optical fiber 56 Disturbing light 58 Amplifying circuit 60 Determination circuit 62 Switch circuit

Claims (4)

An optical sensor that receives light generated by arc discharge and outputs a detection signal;
A display device that displays an alarm according to a detection signal output from the optical sensor;
A light guide in which a light receiving end is arranged in a region where the arc discharge occurs, and the other end is connected to the photosensor;
When a closed loop surrounding the region where the arc discharge occurs is drawn as viewed from the light receiving end side of the light guide, a cone having a circle or polygon circumscribing the closed loop as a bottom and the light receiving end as a vertex is set. A condensing lens system that receives only light within a range in which the arc discharge can be seen from the light receiving end in a state surrounded by the side surface of the cone, and the light receiving end of the light guide. An arc discharge monitoring device characterized by being attached to In the arc discharge monitoring device according to claim 1,
An arc discharge monitoring apparatus, wherein an optical filter that allows ultraviolet light to pass through and blocks other light is incorporated into a part of the condenser lens system. In the arc discharge monitoring device according to claim 1 or 2,
The condensing lens system is a hood formed of a side surface of a cone or a part of a polygonal pyramid having a light receiving end of the light guide as a vertex, and has an inner wall that does not reflect light having a wavelength to be detected; An arc discharge monitoring apparatus comprising an optical system that converts light incident through the hood into light parallel to an optical axis of the light guide at an end. In the arc discharge monitoring device according to claim 3,
An arc discharge monitoring apparatus, wherein the light guide is one or a plurality of optical fibers each having a core and a clad, and is cut at a light receiving end along a plane perpendicular to the optical axis.

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