WO1992010845A1

WO1992010845A1 - Circuits and measurement value receiver for detecting and measuring light sources

Info

Publication number: WO1992010845A1
Application number: PCT/AT1991/000124
Authority: WO
Inventors: Reinhard GÖS; Gerhard Ludwar
Original assignee: Elin Energieversorgung Gesellschaft M.B.H.
Priority date: 1990-12-07
Filing date: 1991-12-04
Publication date: 1992-06-25

Abstract

A circuit arrangement and a measurement value receiver detect and measure light sources, preferably electric arcs in switching appliances. An optical emitter (1) that continuously or periodically emits a signal during measurement time and an optical receiver (3) are linked by a measurement and checking loop (4) composed of two optical waveguides (7, 8) between which is connected an optical measurement value receiver (9). The measurement value receiver to be connected in the circuit arrangement comprises a cylindrical sleeve (57) in plexiglass pushed on the second end (53) of a first optical waveguide (51) and on the first end (54) of a second optical waveguide (53). The cladding (55, 56) of the optical waveguides is glued to the inner side of the sleeve (57). The ends (53, 54) of the optical waveguides are spaced apart on a common longitudinal axis.

Description

CIRCUIT ARRANGEMENT AND MEASURING VALUE RECEIVER

FOR DETECTING AND MEASURING LIGHT SOURCES

The invention relates to a circuit arrangement and a measured value receiver for detecting and measuring light sources, preferably arcs in switching devices such as load switches of tap changers and. like.

The principle of arcing occurs when switching currents. The larger the currents to be switched, the more problematic is the occurrence or the stopping or at least reduction of the arcs. With some switching devices and the associated consumers, for example in the case of load changes in regulating transformers, it is important that the transformer is switched off as quickly as possible if unacceptable arcs occur. Various methods have been proposed to achieve this goal.

Diverter switches for regulating transformers are usually arranged in a cylindrical diverter switch oil tank, which is housed in a transformer tank. The diverter switch oil tank is sealed off from the transformer tank to prevent contaminated diverter switch oil from affecting the insulating strength of the transformer oil.

It has been known for a long time to lead a pipeline from the drive head cover of the diverter switch oil tank, which must not fall below a certain minimum slope and should be laid without any curvature, to an oil expansion tank. In order to avoid that the increase in volume of the Oil causes an increase in pressure in the old expansion vessel, this is connected to the atmosphere at its highest point. This connection is made by means of a ventilation pipe that is guided over a dehumidifier.

To monitor the diverter switch, a protective relay is installed in the pipeline between the drive head cover and the old expansion vessel. This protection relay, which should be located as close as possible to the drive head cover, responds to impermissible errors that occur in the event of a fault

Oil flows between diverter switch oil tank and oil tank. In the event of damage to the diverter switch, an inadmissible arc occurs in the diverter switch oil tank and, as a result, a corresponding increase in the volume of the oil and thus an oil flow or pressure wave. As a result, a built-in damper in the trigger relay is tilted, which triggers a trigger switch coupled to this damper, which then switches off the transformer.

This surveillance system has several serious weaknesses.

Even during normal operation, switching gases accumulate in the protective relay underneath the damper and, when the gas volume reaches a certain volume, cause the damper to tilt and thus turn off the transformer when it suddenly escapes into the old expansion vessel. This leads to false triggers, which are great in some technical areas

cause consequential economic costs and / or safety problems. In practice, it is often unavoidable due to lack of space that the length of the pipeline between the drive head cover of the diverter switch oil container and thus between the

Tripping relay and the Oldehngefäß is relatively large. It also often happens that this pipeline must be laid with several bends for structural reasons. In both cases mentioned, the protective relay often does not respond even in the event of an impermissible overload or other serious errors on the diverter switch.

EP-A1 0 191 398 also discloses a built-in tap changer in which a separate old vessel is arranged just above the tap changer head and is connected to the tap changer head by means of a short pipe socket. This pipe socket opens into a channel arranged vertically in the vessel, the upper end of which has a pressure relief device. This channel is below the minimum

Oil level of the oil expansion vessel, a basically horizontal oil flow line connected, which opens into the actual oil expansion volume of the oil expansion vessel. The oil flow line contains an oil flow relay which, if necessary, causes the transformer to be switched off.

This system also has the disadvantage that erroneous shutdowns of the transformer are triggered by the sudden escape of switching gases accumulating during normal operation.

The object of the invention is therefore to provide a monitoring system with which the deficiencies of conventional monitoring systems are excluded and which immediately reacts to corresponding measured values and forwards them. The object is achieved by the invention. This is characterized in that an optical measuring and test loop consisting of a first and a second optical waveguide is provided, and that a selider continuously or periodically emits light into the first conductor end of the first optical waveguide via an electro-optical converter during the measuring time, and that the second conductor end of the second optical waveguide is connected to a measuring device via an opto-electrical converter and a measuring amplifier, and that the second conductor end of the first optical waveguide and the first conductor end of the second optical waveguide are connected to an optical measured value receiver for one-way optical light transmission, the measured value receiver is located directly at the measuring point.

Since the transmitter continuously or periodically emits light into the measuring and test loop during the entire measuring time, function monitoring is possible at any time, which ensures that a triggering mechanism connected to the circuit arrangement according to the invention responds reliably. Another advantage is that when using optical fibers, no potential difficulties arise even when monitoring high-voltage devices.

In the context of the invention, a measured value receiver is provided for integration into the circuit arrangement, the second conductor end of a first optical waveguide and the first conductor end of a second optical waveguide being inserted into a cylindrical sleeve, preferably a plexiglass tube, with the corresponding length of the respective optical waveguide jacket, and that The inside of the sleeve is glued to the optical waveguide sheaths, and that the second conductor end of the first optical waveguide and the first conductor end of the second optical waveguide are spaced apart from one another common longitudinal axis are arranged, and that the end faces of the conductor ends are designed as optical lenses. The advantage of this measured value receiver is that the light occurring at the measuring point can be coupled into the measured value receiver with little loss.

In a special development of the invention, a filter is placed in front of the end face of the second conductor end of the first optical waveguide, which filter is transparent to the light radiated by the transmitter and highly reflective to the injected light. This prevents part of the light radiated at the measuring parts from flowing to the optical transmitter. In this way, the measuring accuracy of the

Monitoring system significantly increased. A further embodiment of the measured value receiver according to the invention consists in that a quartz glass tube is pushed over the sleeves made of plexiglass.

This training prevents arcing faults from damaging the plexiglass sleeves.

A special development of the invention

Measured value receiver provides that light-scattering material is introduced between the second conductor end of the first optical waveguide and the first conductor end of the second optical waveguide.

This makes it possible to couple more light from the measuring point into the measured value receiver and thus to increase the sensitivity of the measured value receiver. An additional embodiment of the invention provides that the specific requirements for different types of measured value receivers are taken into account by suitable selection of adhesives with different refractive index.

The invention will now be explained in more detail using exemplary embodiments. 1 shows a circuit arrangement according to the invention, while in

Fig. 2 shows a measured value receiver according to the invention.

Glass fibers are used in optical fibers to transmit light waves. The wave range transmitted in this case is between approximately 0.6 to 1.4 μm.

As is known, the current main field of application of lightwave transmission systems is communications engineering. It is possible to simultaneously carry out several light carrier frequencies for signal transmission on a single glass fiber.

However, the use of optical fibers has also been known for a long time in temperature measurement. In communications technology as well as in optical temperature measurement, among other arguments, great reliability and accuracy as well as minimal influence by magnetic and other influences are decisive factors for the use of optical fibers.

Optical fibers, consisting of an inner fiber, which is covered by an outer cladding fiber, are made of multi-component optical glass or purest glass, depending on the area of application. The inner fiber is cylindrical and light-guiding. The light signals are guided according to the physical principle the total reflection. It is important that the refractive index of the inner fiber is higher than that of the cladding fiber. As can be seen in Fig. 1, the output is one

Transmitter 1 connected to the input of an electro-optical converter 2. At the output of the electro-optical

Converter 2, light is coupled into the first end 11 of a first optical waveguide 7. Of course, the radiation should preferably take place in a very narrow solid angle. The second end 12 of the first optical waveguide 7 is connected to a measured value receiver 9, which is arranged directly at a measuring point 10, in the present case with a switch contact. The first end 13 of a second optical waveguide 8 is also connected to the measured value receiver 9, the second end 14 of which is connected to the input of an opto-electrical converter 3. The output of the opto-electrical converter 3 is connected via a measuring amplifier 5 to the input of a measuring device 6.

During the measuring operation, the transmitter 1 sends a continuous or periodic signal, which is converted into light in the electro-optical converter 2 and coupled into the measuring and test loop 4 consisting of the first and the second optical waveguides 7, 8 and to the opto-electrical converter 3 is forwarded. The opto-electrical converter 3 converts the optical signals into electrical signals and passes them on to the measuring device 6 via the measuring amplifier 5.

The measuring and test loop 4 is guided over a measured value receiver 9, which is arranged at the measuring point 10. Occurs at the measuring point 10 light in the form of a

Arc on, this light is coupled into the measured value receiver and forwarded to the measuring device 6. The amount of light coupled in at the measuring point 10 is added to the transmission power and causes a corresponding deflection of the measuring device 6. The measured value receiver 50 shown in FIG. 2 essentially consists of a cylindrical sleeve 57 into which the ends 53, 54 of two optical fibers 51, 52 are used. In the present case, there is the cylindrical sleeve 57 into which the second end 53 of a first

Optical fiber 51 and the first end 54 of a second optical fiber 52 are inserted, made of plexiglass. The inner diameter of the cylindrical sleeve 57 is only slightly larger than the outer diameter of the optical waveguide sheaths 55, 56 and glued to them. If the measured value receiver 50 is provided for the monitoring of switching elements under oil, then this is

Adhesion, of course, oil-proof.

The two conductor ends 53, 54 are arranged at the smallest possible distance from one another on a common axis. The end faces of the conductor ends 53, 54 are lenticular. In order to prevent arcing from attacking the cylindrical sleeve 57, a quartz glass tube 58 is pushed over.

Through special external designs of the respective

Types of measured value receivers can easily take into account special spatial characteristics of different measuring points.

Claims

PATENT CLAIMS

1. Circuit arrangement for detecting and measuring light sources, characterized in that an optical measuring and test loop (4) consisting of a first and a second optical waveguide (7, 8) is provided, and in that a transmitter (1) is connected via an electro- optical converter (2) continuously or periodically radiates light into the first conductor end (11) of the first optical waveguide (7) during the measuring time, and that the second conductor end (14) of the second optical waveguide (8) via an optoelectric converter (3) and one Measuring amplifier (5) is connected to a measuring device (6), and that the second conductor end (12) of the first optical waveguide (7) and the first conductor end (13) of the second

Optical waveguide (8) are connected to an optical measured value receiver (13) for one-way optical light transmission, the measured value receiver (13) being arranged directly at the measuring point (10).

(Fig. 1)

2. Measurement receiver for integration into the circuit arrangement according to claim 1, characterized in that the second conductor end (12, 53) of a first optical fiber (7, 51) and the first conductor end (13, 54) of a second optical fiber (8, 52) in a cylindrical sleeve (57), preferably a

Plexiglass tube, with the appropriate length of the respective optical waveguide sheaths (55, 56) are inserted, and that the inside of the sleeve (57) is glued to the optical waveguide sheaths (55, 56), and that the second conductor end (12, 53) of the first

Optical waveguide (7, 51) and the first conductor end (13, 54) of the second optical waveguide (8, 52) at a distance from each other on a common Longitudinal axis are arranged, and that the end faces of the conductor ends (12, 53, 13, 54) are designed as optical lenses.

(Fig. 1 and 2)

3. Measurement receiver according to claim 2, characterized in that the end face of the second conductor end (12, 53) of the first optical waveguide (7, 51) is a filter which is used for the

Transmitter (1) transmits light and is highly reflective for the injected light.

(Fig. 1 and 2)

Measurement receiver according to claim 2 or 3, characterized in that a quartz glass tube (50) is pushed over the sleeves (57) made of plexiglass.

(Fig. 2)

5. Measurement receiver according to one of claims 2 to 4, characterized in that between the second conductor end (12, 53) of the first optical fiber (7, 51) and the first conductor end (13, 54) of the second optical fiber (8, 52) light-scattering Material is introduced.

6. Measurement receiver according to one of claims 2 to 5, characterized in that the respective specific requirements for different types of measurement receiver are taken into account by suitable selection of adhesives, each with a different refractive index.