EP0537074B1 - Circuit breaker with composite sleeve provided with a monitoring device - Google Patents

Abstract

The present invention relates to a circuit breaker comprising a cutout chamber (1) with composite insulating material sleeve consisting of a cylinder made from glass fibres impregnated with epoxy resin furnished externally with a polymer coating forming vanes and with metal collars (105, 115) at its ends. The circuit breaker comprises an arc-detecting means consisting of a fluorescent optical fibre (102), one end of which is arranged outside and close to the said cylinder and the other end of which is connected to a photodetector (112). <IMAGE>

Description

The present invention relates to a circuit breaker with a composite material casing equipped with a monitoring device. More specifically, it relates to a circuit breaker comprising a cut-off chamber with a casing of composite insulating material consisting of a cylinder made of glass fibers impregnated with epoxy resin provided externally with a polymer coating forming fins and metal collars at its ends.

Such circuit breakers are currently undergoing significant development and, in general, composite insulators used as a support insulator and as an enclosure for an interrupting chamber are increasingly used given their advantageous properties of lightness, good resistance to high pressure, capacity explosion-proof and their competitive cost. These insulators generally comprise a cylinder made of glass fibers impregnated with epoxy resin protected on the outside by a coating with fins of polymer, silicone or EPDM (ethylene propylene diene monomer).

It is important in a circuit breaker to detect the appearance of an electric arc, to measure its duration and to evaluate the intensity of the corresponding current. Knowledge of these parameters makes it possible to assess the wear of the contacts, to check the correct operation of the device and thus to plan maintenance and prevent malfunctions.

In French patent 2,640,386 filed on December 9, 1988 by the Applicant, it is shown that it is possible to use fluorescent optical fibers for the detection of light emanations, visible or not, in apparatus in a metallic envelope.

In European patent application EP-0 482 547 (state of the art according to article 54 (3) EPC) filed by the Applicant, fluorescent plastic optical fibers are used for the detection of the arc duration in a dielectric gas circuit breaker, in particular at SF6. The optical fiber is mounted inside the circuit breaker in the ceramic support column, each of the ends of said fiber being connected to a photo-diode. This arrangement has the disadvantages that the fiber is in contact with the breaking gas and that a sealed outlet of the fiber is necessary.

The present invention relates to a new application of these fibers to the monitoring of circuit breakers with a composite envelope.

According to the invention, which is defined by the combination of characteristics set out in claim 1, the circuit breaker comprises an arc detection means constituted by a fluorescent optical fiber, one end of which is disposed outside and close to said cylinder in a space without coating and the other end of which is connected to a photodiode or to a photodetector.

This arrangement makes it possible to detect from the outside the arc in the breaking chamber during the operations of the circuit breaker equipped with composite insulators.

The fiber is placed at a location where it can detect the arc and, preferably, it is mounted near the lower collar of the breaking chamber.

The epoxy glass cylinder lets in the light created by the cutting arc. The method of mounting the optical fiber which comes first to mind is to drown the fiber placed on this cylinder when the polymer fins are placed on the cylinder. However, this operation requires a temperature greater than 100 ° C. and a fluorescent plastic optical fiber can only permanently withstand a temperature less than or equal to approximately 70 ° C. It is therefore impossible to operate in this direct way.

Two preferential fiber mounting variants are proposed.

According to the first variant, the fiber is directly wound on the cylinder in a space left empty, after completion of the polymer coating with fins, between the collar and the lower end of the coating and embedded in a layer of translucent polymer, an opaque protective layer being disposed on the layer.

According to the second variant, the fiber is housed in the blind hole of a small transparent cylinder, glued with a transparent adhesive on the cylinder before the coating of the polymer coating with fins and coated in the latter, an opaque sleeve ensuring the seal.

At the end of the mounting arrangement of the fluorescent fiber, two preferred embodiments are possible.

According to the first, the breaking chamber is carried by a composite support insulator of identical constitution to that of the breaking chamber and the fluorescent fiber is connected to an ordinary silica optical fiber, which is embedded in the polymer coating along the cylinder of the isolator supporting the breaking chamber, the lower end of the fiber being connected to the photodetector.

According to the second, the breaking chamber is carried by a support and the fluorescent fiber is introduced into an insulator adjacent to the support, its end being connected to the photodetector, at the outlet of this insulator.

It is also useful to know the presence of the voltage on the circuit breaker and it is known to detect the presence of current in high voltage lines using neon lamps. Thanks to the invention, the voltage can be detected with the same optical fiber used for monitoring the arc duration.

To do this, the voltage detection means is interposed between the mounting arrangement of the fiber and the photodetector.

More specifically, preferably, it consists of a metal plate rigidly connected to the socket of the breaking chamber, supporting an insulating bell, tight, opaque, filled with dielectric gas at atmospheric pressure, for example dry air or nitrogen, and crossed by the fiber also passing through an orifice of the plate, a metal rod being fixed vertically on the plate at a certain distance from the fiber.

According to a particular characteristic, the fiber is protected by a transparent glass tube, inside the bell.

In order to carry out a visual check, a second fluorescent fiber can be installed next to the first, its free end opening into the bell.

Other advantages of the circuit breaker according to the invention appear on reading the following description.

The invention is set out below in more detail with the aid of drawings showing only a preferred embodiment.

Figure 1 is a longitudinal sectional view of a first embodiment of a circuit breaker according to the invention.

Figures 2 and 3 are detailed views of this circuit breaker according to a first mounting variant of the optical fiber.

Figure 4 is a detail view of the voltage detection arrangement.

Figure 5 is a detailed view of this circuit breaker according to a second mounting variant of the optical fiber.

Figures 6 and 7 are views in longitudinal section of a second embodiment of a circuit breaker according to the invention.

In FIG. 1 is shown the interrupting chamber 1 comprising inside a fixed contact, a movable contact and sockets 4 and 5. The envelope of this interrupting chamber is made of composite material, namely made of a cylinder 100 made of glass fibers impregnated with epoxy resin protected on the outside by a coating 101 forming fins made of polymer, silicone or EPDM (ethylene propylene diene monomer). Metal collars 105, lower and upper, arranged at the ends of the envelope reinforce the latter. This chamber 1 is placed on an insulating support 6, of the same constitution as the envelope.

A fluorescent plastic optical fiber 102 is placed around the composite cylinder 100 and leaves tangentially thereto, by an arrangement which will be described precisely below. To avoid disturbing the voucher operation of the insulating envelope, this fiber 102 is preferably installed as close as possible to the metal collar 105. The fiber 102 protected by an opaque sheath 106 enters a bell 107 mounted on a support insulator 109 composite of small diameter arranged next to it of the support 6. The precise arrangement of the bell 107 will be specified below. A metal rod 110, the free end of which is rounded and which has a fairly small diameter, is mounted vertically in the bell 107 on a metal plate connected to the socket 5. It is dimensioned to create weak visual aromas by the crown effect, at the minimum phase-to-earth network voltage.

A suitable photodiode or photodetector 112 is mounted at the outlet of the fiber 102 from the support insulator 109. In this way, the fiber 102 permanently picks up the weak light emitted under the crown effect of the rod 110 and sends it to the photodiode 112 which allows the detection of the voltage. Furthermore, during the power cut in the chamber 1, the fiber 102 captures the light from the arc along its length surrounding the cylinder 100, through it. This relatively large light is thus added to that rather weak coming from the bell 107 and its analysis makes it possible to determine the duration of the arc and to evaluate the intensity of the corresponding current.

Continuous recording of the arc duration during opening and during closing allows the wear of the contacts and the proper functioning of the circuit breaker to be assessed.

In the event of non-breaking of the circuit breaker, which results in a long arc duration, general protection can be triggered, especially during non-breaking with a low current, difficult to detect by the usual method.

It should be noted that the support 109 can be used for other applications, for example for the passage of opto-powered optical fibers used with electronic components for the measurement of current and voltage.

A first embodiment of the mounting of the fiber 102 on the envelope of the breaking chamber 1 is now described with FIGS. 2 and 3.

The polymer coating 101 is produced on the cylinder 100 of glass fibers and resin so as to be interrupted at a distance of approximately 5 mm from the metal collar 105. Once this coating has been produced, the fiber 102 is directly wound on the cylinder 100 in the space left empty between the collar 105 and the lower end of the coating 101. It is then embedded in a layer 103 of transparent or translucent polymer crosslinking at a temperature less than or equal to 70 ° C., for example in epoxy resin of the "Araldite" type (R), this layer 103 filling the space left previously empty. An opaque protective layer 104 is then placed on the layer 103, so as to prevent any passage of the light from the fiber towards the outside of the chamber and vice versa. For example, this last layer 104 is made of silicone sealant or polyurethane.

The fiber 102 leaves tangentially to the cylinder 100 in order to avoid an excessively large radius of curvature which would be detrimental to its proper functioning. Just before it leaves layers 103 and 104, it is protected by the opaque sheath 106.

Figure 4 shows in more detail the voltage detection arrangement.

A metal plate 108 is mounted above the support insulator 109 and rigidly connected to the socket 5 of the switching chamber 1 as shown in Figure 1. It supports the insulating bell 107, closed, sealed and perfectly opaque which the fiber 102 passes through which arrives from the periphery of the interrupting chamber 1 protected from its opaque sheath 106. The bare fiber 102 passes through an orifice in the plate 108, to descend along the support insulator 109.

A rod 110 is fixed vertically on the plate 108 at a certain distance from the fiber 102. In order to avoid the effect of excessive scent during an elevation temporary tension, the fiber 102 is protected by a tube 116 made of transparent glass.

The interior space of the bell 107 is filled with dry air or nitrogen at atmospheric pressure. A desiccant 111, for example "Silicagel" (R), is deposited inside the bell 107.

A second fluorescent fiber 102 ′ can be installed next to the first, its free end opening into the bell inside the tube 116. This fiber 102 ′ allows a visual check of the presence of voltage, by simple vision of the light at its end at its lower outlet from the support insulator 109.

To avoid a loss of light transmission in the fluorescent fiber 102,102 ′, it is preferable to use a transparent plastic fiber or an ordinary optical fiber with silica 114,114 ′ at the exit of the bell for the transmission of light along the support insulator 109. This fiber 114,114 ′ is connected to the fluorescent fiber 102,102 ′ by conventional junctions 113,113 ′.

A second embodiment of the mounting of the fiber 102 on the envelope of the breaking chamber 1 is now described with FIG. 5.

This embodiment is suitable for the case where the light emitted by the cutting arc is sufficient even for a weak current. It is then not necessary to capture the light around the entire periphery of the cylinder 100 made of glass fibers and resin.

A small transparent glass cylinder 120, with a diameter of approximately 10 mm and a length of approximately 3 cm, having a blind hole 121 is bonded with a transparent adhesive to the cylinder 100, before the polymer coating is produced. with fins 101. Its end in contact with the cylinder 100 is slightly concave to match the external surface of the latter.

When the coating 101 is put in place, the cylinder 120 is coated by its peripheral surface in the polymer. After polymerization of the coating 101, the end of the fluorescent fiber 102 is introduced and immobilized in the blind hole 121. It is, on the outside, protected by the opaque sheath 103 and by an opaque sleeve 122 made of elastomer, which seals.

Fiber 102 has a diameter of about 1 mm. The light from the cutting arc passes through the cylinder 100 and the small cylinder 120 and is captured by the fiber 102 over a length of the order of 2.5 mm and on its transverse end surface.

Figures 6 and 7 are views in longitudinal section of a second preferred embodiment of a circuit breaker according to the invention.

According to this embodiment, a second support insulator 109 is not used.

According to FIG. 6, at its exit from the mounting arrangement on the envelope of the breaking chamber 1, the fluorescent fiber 102 protected by its opaque sheath is connected by a connector 202 to an ordinary optical fiber 200, for example at silica, which is embedded in the polymer coating along the glass fiber and resin cylinder of the support insulator 6 of the breaking chamber 1. The lower end of the fiber 200 is connected to a photodiode or to a photodetector 112.

FIG. 7 represents an analog circuit breaker, with a voltage detection device identical to that described above and mounted in an analogous manner, interposed at the end of the fluorescent fiber 102 before the connection of the latter with the ordinary fiber 200 by connector 202.

Claims (10)

1. A circuit-breaker including an interrupting chamber (1) having a casing made of a composite insulating material and constituted by a cylinder (100) made up of glass fibers impregnated with epoxy resin, the outside of the cylinder being provided with a fin-forming polymer covering (101), and with metal collars at its ends, said circuit-breaker further including arc detection means constituted by a fluorescent optical fiber (102), one end of which is disposed outside and in the vicinity of said cylinder (100), in a gap not containing any of said covering (101), the other end of the fluorescent optical fiber being connected to a photodiode or photodetector (112).
2. A circuit-breaker according to claim 1, characterized in that the fiber (102) is mounted in the vicinity of the bottom collar (105) of the interrupting chamber (1).
3. A circuit-breaker according to claim 2, characterized in that the fiber (102) is wound directly around the cylinder (100) in a gap left empty after the finned polymer covering (101) has been implemented, between the collar (105) and the bottom end of the covering (101), and is embedded in a translucent polymer layer (103), with an opaque protective layer (104) being disposed on the translucent polymer layer (103).
4. A circuit-breaker according to claim 2, characterized in that the fiber (102) is received in the blind hole (121) of a small transparent cylinder (120) that is glued by means of a transparent adhesive to the cylinder (100) before the finned polymer covering is implemented (100), and that is coated therein, an opaque sleeve (122) providing sealing.
5. A circuit-breaker according to any one of claims 2 to 4, having its interrupting chamber (1) carried by a composite supporting insulator (6) constituted identically to the interrupting chamber, said circuit-breaker being characterized in that, on exiting from the fiber-mounting arrangement, the fluorescent fiber (102) is connected to an ordinary optical fiber (200) which is embedded in the polymer covering along the cylinder of the supporting insulator (6) of the interrupting chamber (1), the bottom end of the ordinary optical fiber (200) being connected to the photodiode or photodetector (112).
6. A circuit-breaker according to any one of claims 2 to 4, having its interrupting chamber (1) carried by a support (6), said circuit-breaker being characterized in that, on exiting from the fiber-mounting arrangement, the fluorescent fiber (102) is inserted into an insulator (109) adjacent to the support (6), the end of the fluorescent fiber being connected to the photodiode or photodetector (112) on exiting from the insulator (109).
7. A circuit-breaker according to any preceding claim, characterized in that voltage detection means are interposed between the photodiode or photodetector (112) and the mounting arrangement for mounting the fiber (102).
8. A circuit-breaker according to claim 7, characterized in that the voltage detection means are constituted by a metal plate rigidly connected to the terminal (5) of the interrupting chamber (1), which metal plate supports a bell-shaped cover (107) which is insulating, gastight, opaque, and filled with dielectric gas at atmospheric pressure, the fiber (102) passing through the cover and through an orifice in the plate, and a metal rod (110) being fixed vertically to the plate at a certain distance from the fiber (102).
9. A circuit-breaker according to claim 8, characterized in that the fiber (102) is protected by a tube (116) made of transparent glass, inside the cover (107).
10. A circuit-breaker according to claim 8 or 9, characterized in that a second fluorescent fiber (102') is mounted next to the first fluorescent fiber, the free end of the second fluorescent fiber being disposed inside the cover (107).

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