JPS59116704A - Optical fiber cable and usage thereof - 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 fiber optic cables, and in particular to fiber optic cables suitable for being mounted in close proximity to or in physical contact with high voltage equipment, such as high voltage conductors. and relating to arrays including fiber optic cables.

By high voltage equipment is meant equipment such as 1KV or higher, eg 33KV or 400KV power conductors.

The use of fiber optic cables with such high-voltage conductors has been established in the United Kingdom [Publication No. 208364].
7AQ# and No. 2101351A. These public notices are light)? discloses an arrangement in which the fiber optic cable passes inside the high voltage conductor, so that the fiber optic cable is not exposed to electric field gradients. This arrangement feeds the cable away from the conductor in a metal housing and through a ceramic chamber filled with insulating oil to ground potential. D 1 stribu
-tion [)developments (19
(September 1982) describes attaching fiber optic cables to overhead cables with outer sheaths made from non-racking, low corrosion compositions.

The present invention is a cable that can be used in close proximity to and exposed to the electric fields of high voltage equipment, such as high voltage conductors, switches, transformers, motors and generators,
It is an object of the present invention to provide a cable or fiber optic cable or cable arrangement that can be routed into or around equipment at different potentials, including ground potential, without adversely affecting the operation of the cable.

Fiber optic cables are used to carry coded data, such data in digital or analog form, for the purpose of monitoring and controlling electrical networks of which the conductors form part, for example. It can be used for

However, the cable may be used to carry data that is not suitable for network operation. Such data includes communications and similar signals typically carried by fiber optic links. In addition, the fiber optic cable itself is equipped with sensors for monitoring operating parameters of electrical systems, including conductor systems.
It can be used as

According to one aspect of the invention, the invention comprises a high voltage conductor (which may be uninsulated) and a fiber optic cable adjacent to or in contact with the conductor, the cable having an arrangement having an electrically protective jacket. provided. Advantageously, the jacket 1 is made of a substantially electrically non-heracking material and may be electrically insulating and substantially non-wetting and weatherproof.

Thus, if such a jacket or coating is applied to a -C fiber optic cable throughout its length, the cable may be applied to the surface of the energized conductor. For this latter application to be successful, i.e. for the arrangement to ensure that the integrity of the cable and therefore the optical signals carried remain intact, the coating must be able to absorb the electrical energy generated from the electric field surrounding the conductors. It must be strong enough to withstand activation.

Three very difficult problems need to be resolved before the array can be expected to provide acceptable long-term performance. The three problems include controlling stress at the point where the fiber optic cable leaves the high voltage conductor and at the point where the cable approaches ground potential or earth potential; and the resulting contamination along the surface of the fiber optic cable sheath. control of surface leakage current; and preserving the integrity of fiber optic cables after outdoor exposure to long-term high voltage stresses. These common types of problems are known in the power distribution industry, where typical equipment including isolators, cable terminations, etc. must encompass phase and ground potentials, so these problems can be avoided. The steps have been taken in mind.

However, solutions suitable for isolators or high voltage power cables are not suitable for fiber optic cables.

Stress control at the cable terminals is achieved by resistive or capacitive coupling to the center conductor of the cable carrying the power. However,
Optical cables do not have such conductors. As such, it may be considered more similar to high voltage insulators. A single high-voltage insulator is designed to control surface leakage current by supplying a shed (sbed) to its surface. The shed has various functions. The edge increases the side distance by more than three times the face-to-ground distance and provides a large number of 1-dry areas of relatively high resistance that can keep cracking currents at an acceptably low level. Cover the protected area to limit the contamination of contaminants.

In comparison, the diameter of fiber optic cable is typically 1/10 to 1/100 the diameter of high voltage insulation, and fiber optic cable has very weak strength. It is clearly impractical to provide a shed area to achieve the same result as a high voltage insulator, and the proposed solution is needed to solve both problems.

The insulator has a solid core or is filled with oil to eliminate or at least reduce the internal discharge activity, which can lead to destruction. 'Take S-zo. In comparison, optical fibers often have a "rusticoved" structure, or are stacked in such a way as to form an elongated interior space. Since air is a good dielectric material,
Such spaces are considered small enough to have a negligible effect on the structure. However, experience and experiment show that such spaces are detrimental to the longer service life and need to be eliminated or their detrimental effects reduced in some way.

One object of the present invention is to prevent, or at least reduce, damage to fiber optic cables that are placed in regions of conductors, including regions where they leave high voltage conductors, and are therefore exposed to leakage current flow along them. There is a particular thing.

Another object of the present invention is to minimize the deleterious effects of leakage or induced currents, such as the optical signal of the IJ 715 and Mazeka1.

Still, in accordance with a specific aspect of the invention, there is provided a fiber optic cable configured to be suitable for use at high voltages, such as by being mounted adjacent to or in contact with a high voltage conductor. Ru. Conveniently, the cable may be spirally wrapped around a conductor, which may be an overhead line conductor. Allows to be used in close proximity to switchgear or transformers.

The fiber optic cables of the present invention may be of any suitable form and may include, for example, one or more optical fibers, each optical fiber within a respective sheath, and where more than one fiber is present. , the optical fibers may be grouped together and housed within a single outer sheath.

In accordance with the above and other aspects of the invention, two forms of high voltage fiber optic cable are contemplated, which can be used independently or in conjunction with each other. In addition to the elements described above, the optical fiber cable may include other elements.

A first form of a fiber optic cable of the invention comprises a substantially non-tracking outer jacket, a non-metallic reinforcing member, one or more fiber optic elements and a compatible protective filler. .

The filler is substantially arranged to eliminate or at least prevent the formation or presence of very long voids or significant moisture ingress into the structure in the event of holes in said outer protective jacket 1. . The same filler may be used to achieve each of these effects, or different fillers may be required.

Compatible fillers may be incorporated into the construction during manufacture and may be made from similar materials as the jacket. i.e. gum-like materials, such as gum-like substances based on silicone, butyl or ethylene/propylene elastomers; waxes, sherry-like substances;
For example, it may be petroleum sherry; or an oil that is incorporated into the structure during manufacture or later introduced into the interstices of the structure.

The filling material may be of the same material as the cable jacket and integral with the jacket, the filling of the cable being carried out at the time of adding the jacket during manufacture, for example by complete integration of the braided elements.

The jacket and filler may subsequently be crosslinked by high energy radiation or chemical means.

The second form of the high voltage optical fiber cable of the present invention is
It comprises an electrically conductive outer jacket (which may be either metallic or polymeric), a reinforcing member and one or more fiber optic elements.

The fiber optic cable of the first form may be mounted adjacent to or in contact with the high voltage conductor and may lead from the high voltage conductor to the ground. The second type of cable is particularly suitable for operation at a single potential and may be connected to the first type of cable for transmission between high voltage and ground potential.

However, the more concise construction and conductive outer sheath of the second form is particularly suitable for mounting the cable adjacent to conductors operating at high voltages, whereas the second form
Cables in the form of are particularly suitable for transmitting high voltages to ground potential.

However, the uses are not limited to these.

The material of the outer jacket of the fiber optic cable of the present invention is selected depending on the electrical atmosphere in which it is placed. For cables exposed to high voltage fields, e.g. wrapped around uninsulated overhead cables, length 1
A conductive outer jacket of a material having a resistance of about 106 ohms per cm or less is suitable. Such materials generally ensure that the potential of the cable jacket is close enough to the potential of the conductor that any surface discharge activity that may occur on the cable is low enough that damage to the jacket does not occur. However, if the jacket is insulative with a resistance of 107 or 108 ohms/cm or more, it may be roughly surrounded by a jacket of non-tracking insulating material or completely covered with such non-tracking insulating material. must be made of. The cable jacket therefore has a protective outer surface even if there is a significant potential difference between the conductor and the cable. If the fiber optic cable is required to extend between phase potential and ground potential, the outer jacket must have a resistance of at least about 107 or 108 ohms/cm and be non-tracking.

If the resistance of the outer jacket 1~ of such a cable is too low, the leakage currents and power dissipation flowing along it become unacceptably high. It is therefore understood that at high voltages electrical tracking along the cable surface must be minimized, while at low voltages leakage currents must be kept within an acceptable range. The specific resistance limit therefore depends on the operating voltage to which the cable is exposed.

Although it is usually desirable to fill a fiber optic cable only when an insulating outer cover is provided, in some situations it is advantageous to fill the cable when it has a conductive outer cover. For example, fiber optic cables may be provided with a non-tracking jacket and placed within a metal tube. Such tubes improve the physical and moisture protection of the cable. However, when connecting or terminating such cables, the metal duplex must be removed at the end of the cable, thus exposing the cable to axial ingress of moisture.

In such situations, water blocking of the cable becomes advantageous. Filling or blocking the cable is particularly important when the cable connects conductors at distinctly different voltages, for example phase voltages, and ground potential. However, if water were to come into contact with the glass fiber, for example, the ingress of moisture in any part of the cable could damage the optical properties of the fiber over time.

In other forms of the optical fiber cable of the present invention,
Only a portion of the cable has an electrically conductive outer conductor, which portion is arranged to contact a high voltage device, such as a power conductor, in use.

According to another aspect of the invention, there is provided a fiber optic cable suitable for extending between a high voltage region and a significantly lower voltage region, wherein in the high voltage region the cable has an electrically conductive outer jacket; In the area the cable is provided as a fiber optic cable having an outer jacket of substantially electrically non-tracking material.

The lower potential may be ground potential.

The non-tracking outer JAWOOD material used at low potentials and preferably in the transition region from high potentials may replace the conductive jacket material or may be provided as another layer thereon. .

According to the invention it is furthermore suitable for use at high voltages where it is to be exposed to high voltage stresses and which is mounted, for example, next to or in contact with a high voltage conductor and which is above ground at one or both ends. A fiber optic cable is provided that may be connected to an electrical potential.

Further in accordance with the present invention, a fiber optic cable incorporating stress control means is provided.

In addition, the invention provides a cable for use at high voltages, wherein at least one end of the cable terminates a fiber optic cable in such a way that it is protected against environmental contamination, for example. A means is provided for this purpose.

The cable may be disposed within the tubular member and may, but need not, be externally sealed. For example, the protective housing of the tube may be perforated, for example to exclude the formation of moisture.

Also according to the invention, at least one end of the cable is arranged in such a way as to minimize or at least reduce the adverse effects of leakage current flow along it. Means are provided for terminating the cable.

Accordingly, the present invention provides that any leakage current flowing along a high voltage device, a fiber optic cable and a cable jacket arranged on the outside of the conductor in use so as to be exposed to the electric field of the device is at ground potential. An assembly is provided comprising electrically conductive means mounted on a cable for conducting to the cable.

The high voltage device may be a high voltage conductor.

The means for conducting leakage current to ground potential may be an earth leakage current collector or a means for reducing leakage current density;
Conveniently, it may consist of two electrically conductive halves clamped directly to the cable. As mentioned above, if the cable itself is enclosed within an environmental protection member, the earth leakage current collector, as well as the conductive mass, connects the member to ground, thereby eliminating any leakage current collected in the member. It may further include means for grounding.

Such grounding means can be used in conjunction with the fiber optic cables and other assemblies of the present invention.

Alternatively, the earth leakage current collector may be provided with a composite array comprising a pair of insulating, e.g. The body collides with a pair of grounding metal halves mounted on the cable in the direction of the lower potential. Such an arrangement is described in UK Patent Application No. 831289:2@.

According to another aspect of the invention, a high voltage device, for example a cable comprising a high voltage conductor, a fiber optic cable arranged outside the device in use so as to be exposed to its electric field, and electrical stress control means. An assembly is provided in which any electrical stress resulting from the electric field generated by the conductor and to which the cable is exposed is substantially insufficient to cause damage to the fiber optic cable.

For example, perforations allow water to enter, causing adverse effects such as illumination interference and spurious optical signals.

According to another aspect of the invention, there is provided a method for providing electrical protection to an optical fiber cable placed outside an electrical device and exposed to the electric field of the device, the method comprising: The electrical stress resulting from the electric field and to which the cable is exposed is substantially insufficient to completely damage the optical fiber part and to avoid other adverse effects of minor magnitude (above t). A method is provided in which stress control means are provided.

The cable extends over or to the side of the conductor and is preferably spirally wound around the conductor.

According to the present invention, a fiber optic cable can be attached to the outside of a high voltage (e.g. removed from the conductor) or connected to the length of the conductor. A5 can be placed in any position and safely led to positions of distinctly different potentials without terminating, connecting, or interfering with the conductor itself.

The present invention makes it possible to extend fiber optic cables from high-voltage devices and connected sensors to much lower, eg, ground potentials.

The stress control means are such that the cable is moved away from the direct vicinity of the conductor's electric field! In our case, it can be arranged to surround the optical fiber cable.

Preferably, the electrical stress control means comprises an electrically conductive housing made of conductive polymer 4A diagonal or metal, the housing being attached to the device and the cable leaving the device in a different manner. The electric field of the housing is arranged to pass through a clearly reduced environment towards the part having a higher potential, for example the part having ground potential.

Thus, the housing can provide an enclosure that is substantially free of the electric fields associated with high-voltage conductors, and thus fiber optic cables were originally designed to be can be removed from the conductor in the region of , and can be directed away from the high voltage conductor to, or at least towards, a location of very low potential. Therefore, when the fiber optic cable exits the housing and enters any electric field of the conductor, it is ensured that the electric field strength is so small that it does not cause any substantial disturbance of the couple or have the adverse effects mentioned above. Therefore, the housing needs to extend away from the conductor. For this purpose, the form of the housing must be such that it reduces the influence of electrical stresses from the electric field of the conductor. Advantageously, the cable outlet of the housing is directed outwardly away from the conductor, and may also be conical (or bell-shaped). may be different for high voltage conductors of different voltage classes in order to optimize the electrical protection of the optical fiber. It is not necessary to completely physically enclose the cable.Furthermore, the housing generally does not need to carry appreciable current.For these reasons, the stress control means may be used in a partially open configuration. , for example, a fiber optic cable may be a grid-like wrapping of electrically conductive material around the area away from the direct vicinity of the electric field of the high voltage conductor.

Furthermore, it is also conceivable to arrange the electrically conductive housing in such a way that it protects the cable in a position where it is brought to ground potential.

Preferably, the housing has a passageway through the housing and an inlet and an outlet 85 separate from but in communication with the passageway, such that the high voltage conductor extends through the passageway and through the housing. supporting the fiber optic cable is spaced from the conductor just outside the housing and arranged to enter through the inlet and exit the housing through the outlet. It will be appreciated that the fiber optic cable must not enter the housing sufficiently close to the housing to leave the conductors and therefore not cause a significant potential drop along the fiber optic cable. Preferably, the fiber optic cable should not extend to the side of the high voltage conductor for about three times the diameter of the conductor before entering the conductive housing.

On the other hand, the fiber optic cable may enter into the passageway of the housing with the conductor, thus leaving the C-conductor within the housing itself.

The housing may comprise two half-shells, the half-shells being secured together, for example by screws, to allow the conductor to pass therethrough and to allow the conductor to pass in the transverse direction. allow it to stretch.

Preferably, the housing is outwardly directed and directs the fiber optic cable away from the conductor.

The housing may be split into two halves at one end, so that the housing can be pushed onto the conductor. The housing is also supplied with enclosing keys such as screw-fits, push-in fittings, or subops. Alternatively or additionally, the housing may be a two-part suitable 11
The stop (14) may be a right-handed housing or may be of one-piece wraparound configuration. The housing may be substantially elongated or may have some other shape, such as a T-shape. In the case of a 1,1 shape, the T-shaped arms extend over the conductor.

In one form, the housing is generally long and may be bifurcated at one end to provide a cross passage for receiving the conductor, and the use of the housing to direct the fiber optic cable away from the conductor. It has an outlet at the end.

Preferably, the housing is environmentally sealed over the high voltage conductor, advantageously using conductive MASDECK or SEALAN 1-.

The protection of the fiber optic cable from, for example, water, salt or other sources of contamination after leaving the housing can be provided by an electrically insulating, non-tracking, preferably tubular member. The protection member is interengaged with the housing and guides the cable leaving the housing all the way, advantageously to the ground point. This member may have a conical shape and/or a shed on its outer surface.

U.S. Pat. No. 3,746,424 discloses a separating device for guiding a bundle of optical fibers from a current measuring device associated with a high voltage conductor to a sensing device at ground potential.
There is C. The patent discloses that the separation device 1 has a plurality of skirt portions along its length. however,
For example, there is no disclosure that the bundle of optical fibers extends outside the conductor so that it is exposed to the electric field of the conductor.

Further protection of the optical fiber can also be achieved by completely shielding the area between the cable and the surrounding housing and/or insulation member. One way to achieve this is to apply an insulating part (such as shrink, e.g. heat shrink) onto the fiber optic cable, preferably an inner sealant or an adhesive coating, e.g. Another method is to supply the adhesive.Another method is to ensure that the area between the optical fiber cable and the insulating member is filled with oil, ltl fat, foam or other suitable insulating medium. It is to do so. When making such a supply, the stop to the conductor of the housing is not very important and may therefore be completely omitted.

In another form of the assembly of the invention, the stress control means may be placed where the cable is initially exposed to a high voltage and approaches or reaches a much lower potential, such as ground potential. Such stress control means act as earth leakage current collectors, thus ensuring safe grounding of the cable without significant electrical damage or reducing stray currents or other adverse effects.

The present invention further provides a method for applying stress control to fiber optic cables that leave the immediate area of the electric field of a high voltage conductor and are led to a distinctly lower, eg ground potential.

Depending on the operating conditions, the above-mentioned characteristics, i.e. electrical stress control means that minimize the electrical stress to which the fiber optic cable is exposed, means for grounding leakage currents flowing along the cable, and significantly An assembly is provided comprising any two or all three of the environmental protection means of cables extending to locations of different potentials, for example from high voltage to ground.

One advantageous arrangement of the invention is that the fiber optic cable is combined with a high voltage conductor, which may be an overhead conductor, so that substantially no electrical damage occurs to the cable where it leaves the conductor. JIJ stress control means, a protective tubular member for guiding the cable towards a significantly lower potential, e.g. and a stress control means for terminating the cable.

The tubular member of the present invention extending from the high voltage region has a convoluted shape to extend the creepage path length.
ted) d5 and/or a shredded outer surface. Its inner surface may be convoluted. The tubular member is insulative, non-racking and weatherproof and may be filled to prevent water flow.

It will be understood that an arrangement of the invention may optionally include a fiber optic cable of the invention, and an assembly of the invention may likewise contain an arrangement or a fiber optic cable of the invention. .

A method of providing electrical protection to a fiber optic cable combined with a high voltage conductor and an assembly comprising a fiber optic cable, a conductor and a conductive housing according to the invention will now be described with reference to the accompanying drawings. Detailed explanation 1-.

Figure 1 is a cross-sectional front view of the housing; Figure la is a half cross-sectional front view of another embodiment of the housing; Figure 2 is a side view of one embodiment of an assembly including the housing of Figure 1; Figures 2a, 3 and 4 are side views of other embodiments of the assembly; Figures 5a and 511 are side views of other embodiments of the assembly;

3 and 4 respectively; FIGS. 6a, 6b and 6C are partial cut-away and cross-sectional views showing variations of the parts of the assembly of FIGS. 3 and 4, respectively; FIGS. Schematic diagram; FIG. 7 is a longitudinal sectional view of another housing suitable for carrying out the installation of fiber optic cables; and FIG. 8 is a longitudinal section of another housing suitable for carrying out the installation of fiber optic cables; 8 is a schematic diagram of the assembly of FIG. 3 including the installation housing of FIG. 7; FIG.

In FIG. 1, housing 2 is made of a conductive polymeric material and provides protection for fiber optic cables running along high voltage conductors. The conductors and cables are shown in outline in FIG. These are explained in more detail with reference to FIG. The housing 2 includes a first elongate section 4 which is open at both ends and has an upper section 6 which is generally cylindrical. The upper part connects below with a generally conical part 8. Housing 2 is
It has a second part 10 which provides an enclosing cap for the housing part 6, and for this purpose the enclosing key 10 has an internal thread and a cylindrical part 6.
has external threads mating thereto.

The cylindrical portion 6 is bifurcated at its open end, in which a slit 12 extends from the open end to a generally circular opening in the opposite side wall of the portion 6. The opening defines a generally tubular 9 passageway 14 through section 6 .

FIG. 2 shows the housing 2 of FIG. 1 mounted over a high voltage uninsulated overhead conductor 16 that is spirally wrapped around a fiber optic cable 18.

Cable 18 may be of any construction previously described. Bifurcated cylindrical part of housing 2, min 6
are widened to enlarge the slit 12 so that the conductor 16 can be passed along the slit and placed within the housing passageway 14. A fiber optic cable 18 extends into the passageway 14 with the conductor 16, but separates from the conductor 16 within the housing 2 and extends downwardly through the open end of the conical housing portion 8. To prevent moisture ingress into the housing along the passageway 14, a conductive mastic 1420 is wrapped around the cable carrying conductor 16 where the conductor enters, passes through, and exits the housing. ing. The slit 12 is then closed and the housing cap 1o
is screwed onto the cylindrical part 6, thereby sealing the upper part of the housing □.

Figure 1a shows the half body 3 of the metal housing.
It shows. This half is secured to the corresponding half by screws or bolts and encloses the high voltage conductor.
Ru. The housing formed from the half bodies 3 performs the same electrical function as the housing 2 of FIG. It is growing as one. Accordingly, the conductor extends through the channel 5, the fiber optic cable enters through the hole 7, and the internal rib 9 provides a protective tube (not shown) for guiding the fiber optic cable leaving the conductor longitudinally.
It is for fixing.

J5 in FIG. 2a, the assembly is housing 21.
However, the housing 21 differs from the housing 2 in the way the fiber optic cable 18 enters. In this arrangement, the cable 18 is separated from the conductor at a distance of about 5 Qmm before the conductor enters the housing. has been done. The cable 18 then extends over the housing cap 23.

The housing cap has a hole 25 that allows the cable to extend downwardly within the housing 21. In a further alternative, the introduction hole 27 for the fiber optic cable 18 is provided in the side of the cap, the passage of the cable being therefore indicated by dashed lines in FIG. 2a.

Cable 18 is connected to conductor 16 as shown in FIG.
rather than being introduced along holes 25 or 2
7 into the housing 21, there is no wear and tear between the fiber optic cable 18, the conductor 16 and the housing introduction passage. Furthermore, because the cable 18 is separated from the conductor 16 only for a short distance before entering the conductive housing, the cable is not exposed to significant electrical stresses.

The configuration of the housings 2 and 21 ensures that where the fiber optic cable 18 extends from the conical portion 8, electrical stresses on the cable caused by the electric field associated with the conductor 16 can damage the cable or have other adverse effects! It is made so that it is not enough to grow.

For this purpose, the length of the housing 2 and the circle 1 ([
Each parameter, such as the angle of the shaped portion 8, is selected according to the voltage class of the conductor 16. For 33KV conductor,
If the conical surface of the housing makes an angle of approximately 10° to the normal, the length of the housing extending below the conductor, for example, is typically 5-8 cm (see drawing).
.

In the improved assembly shown in FIG.
Mechanical protection can be provided to the fiber optic cable 18 by surrounding the cable with a convoluted chicove 22 of electrically insulating polymeric material where it leaves the housing. The tube 22 engages the threaded portion 23 of the cylindrical housing part 6 from the inside and extends downwardly from the open end of the housing 2.

Another embodiment of the assembly shown in FIG. 4 has a housing 24 that differs from housing 2 in having external screw threads 26 at the lower open end. One end of a convoluted tube 28 is attached to the thread.

The protection assembly of FIG. 4 has the following advantages over the protection assembly of FIG.

That is, the housing 24 does not shield the tube 28 from water, thereby minimizing the risk of dry band formation on the outer surface of the housing and tube combination. The desiccant band, in the assembly of FIG. 3, can in some circumstances cause electrical damage to the tube through conditions such as tracking and corrosion.

Figures 5a and 5b show an alternative means for convoluted tubes 22 and 28 to guide the fiber optic cable from a high voltage area to a low voltage area. This is particularly, but not exclusively, applied to high voltage applications where increased creepage path length is required, such as 132 KVIJ. That is, the fiber optic cable 50 is comprised of five optical fibers surrounding a reinforcement shrine in a completely water-blocked configuration and embedded within a non-racking outer jacket 52. The outer jacket 52 has a shed 54 on its outer surface.

Alternative housings such as housings 2, 21 & 5 and 24 previously shown are shown in Figures 6a, 6b and 6c. The housings of FIGS. 6a, 511, and 6 often have a helical structure of metal or fairly rigid conductive polymer, providing a substantially spherical enclosure and Mounted on high voltage conductors.

The housing 56 of FIG. 6a is generally wrapped around a vertical axis and clamped to the conductor 62 at radially opposed locations 58,60. A fiber optic cable 64 extending spirally along conductor 62 is guided from the conductor into housing 56 by coiled member 66 and passes through a cable splice enclosure, shown schematically at 68. The enclosure is attached to housing 56.

After being connected within the enclosure 68, the fiber optic cable may be convoluted and/or shed as shown above.
Leaving housing 56 within tube 70 .

The housing 72 of FIG. 6b differs from that of FIG. 6a in that it extends spirally around an axis coinciding with the overhead conductor. The fiber optic cable sheathing, connections and subsequent guidance are not shown but are conveniently similar to those previously described.

Housings 5G and 72 in Figures 6a and 61)
It is understood that the above shall normally be attached to the overhead conductor without cutting the conductor. That is, these housings must be installed (pull) from the side of the conductor rather than being inserted from one end of the conductor. May make installation difficult.

The housing 73 of FIG. 6C overcomes this difficulty.
This is what I did. This is because the housing 73
Made from a metal or conductive polymer tubular section (A) of considerable stiffness, the section O Δ is joined at its midpoint to form a U-shape, and then the legs of the U-shape are connected in opposite directions. This is because the housing 73 is wrapped around the mandrel so as to extend in the axial direction toward the housing 73.
It is mounted by hooking its midpoint onto the conductor and then rotating the entire housing around the conductor until gripping engagement is achieved at each end of the housing.

FIG. 7 shows a housing 74 suitable for mounting in a convoluted chicove for guiding a fiber optic cable from an overhead conductor to a station at ground potential and serving as a stress control arrangement, a grounding medium, and a ground leakage current collector. has been done. The housing also functions as an enclosure for an optical fiber connection or connector.

Housing 74, shown open in FIG.
generally semi-cylindrical brass half shells 76, each half shell having an integrally ribbed neck for gripping a convoluted tube 8o leading to a fiber optic cable 82. It has a section 78 at each end. Another pair of generally semi-cylindrical brass half shells 84 include:
It is located within the housing 74 and is tightened into contact with a half shell 76 on the enclosure of the housing. A non-tracking convoluted tube 8o extends into the housing and the fiber optic cable 82 exits therefrom and passes through the passageway formed by the half shell 84. The larger upper part of the passage is
It loosely surrounds the fiber optic cable and is filled with a potting composition. The narrow lower part, on the other hand, grips the fiber optic couple tightly but does not damage the fiber optic cable. Therefore, the housing 74 is
In direct electrical contact with the outer non-1-racking tube 80 and fiber optic cable 80 . A conductive connection stand 86 is located on one outside side of the half shell 76 -F.
and a conductor (not shown) extends therefrom to a point at ground potential.

The housing 74 includes a schematically shown splice enclosure 88 from which the fiber optic cable is communicated through the other part of the convoluted tube 8o to the decoding station.

It is noted that in many cases it is not necessary to protect the optical fiber cable, for example by a convoluted cable (depending on whether or not the high-voltage control arrangement h1 is used in the cable). Don't understand that that's the case (JreG
, 1: No. Therefore, when referring to FIG. 7 of C1, if an insulating non-rucking convoluted protective tube is required to protect the optical fiber cable 82, a pair of earth leakage current collectors 74 are required. The outer half sealer 6 may be omitted. In this case, half shell 84 is connected directly to ground potential.

In FIG. 8, a high voltage conductor 3o having a spirally wrapped fiber optic cable 18 is shown at a height of 1 from a switch/transformer station (not shown).
0111 onto the support ball 32 and thence to the terminal switch/transformer station 34. The conductor 30 is secured to the ball 32 by a tensioning device 36;
It is electrically isolated from the ball by an insulator 38.

Immediately before reaching the ball 32, the fiber optic cable 18 connects to the drop-in line 4o and leaves the main conductor 30. The retraction wire 1740 is crimped to the main conductor 3o at one end, and the surge wire is crimped to the main conductor 3o at the other end.
A diverter 42 is connected to the ball 32 which is then at ground potential. The drop-in line 40 is therefore at the same voltage as the conductor 3o, for example 33 KV. Fiber optic cable 1
8 separates from the lead-in wire 4o via the conductive housing 2 or 21 before the leezy diverter 42, and then passes through the insulated convoluted tube 22 fixed to the ball 32. At the lower end of the ball, the optical fiber group leaves the conductive tube 22 and opens into a switch (not shown). )to go into. The switch is at ground potential.

This occurs after the cable and chicof have been installed as shown, for example with housing 74.

Typically, conductor 30 is accompanied by two other conductors, thus providing a three-layer alternating current, but only one of the conductors
It is understood that it is generally required to carry fiber optic cables.

It is understood that the features of the fiber optic cables and cable arrangements described herein may be combined as appropriate to achieve particular objectives.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional front view of the housing; FIG. 1a is a half cross-sectional front view of another embodiment of the housing; FIG. 2 is a side view of one embodiment of an assembly including the housing of FIG. 1; Figures 2a, 3 and 4 are side views of other embodiments of the assembly; Figures 5a and 5b are side views of Figures 2 and 2a. A partial cutaway J3 and cross-sectional view showing no deformation of the portion of the assembly of FIGS. 3 and 4, respectively; FIGS. 6a, 6b and 6C are portions of another assembly including other aspects of the housing. Schematic representation of: Figure 7 is a longitudinal section of another housing suitable for carrying out the installation of fiber optic cables; and Figure 8 is a longitudinal section of another housing suitable for carrying out the installation of fiber optic cables; There is a schematic diagram of the assembly of Figure 3 arranged and including the installation housing of Figure 7: 2... housing, 3... halves, 4... first extension portion, 5... channel. , 6... Cylindrical portion, 7
... Hole, 8... Circular part, 9... Rib, 10.
...Second part, 12...To Surin 1, 14...Passway, 16...Conductor, 18...Optical fiber cable,
20... Mastic 41 size, 21... Housing,
22... Convoluted tube, 23... Cap, 25
... hole, 27 ... hole, 28 ... convoluted tube,
30... Conductor, 32... Ball, 36... Tension device, 38... Insulator, 40... Lead wire, 52... Outer gillette, 54... Shed, 56... Housing, 62... Conductor, 64... Optical fiber cable, 6G... Coiled wire, 70... Duplex, 7
2...Housing, 74...Housing, 76...
-Half shell, 78...Neck part, 80...Tube, 84...Half shell. Patent applicant: Raychem Limited Agent: Patent attorney: Mr. Ishikawa and 2 others (GB)■83110
48 V Inventor John Sitney Thomas Rooms 13-43 Beauchaup Road, East Molsey, Surrey, England

Claims (1)

Claims: 1. A fiber optic cable suitable for high voltage use, the cable comprising a substantially non-tracking outer jacket, a non-metallic reinforcing member, at least one fiber optic element and a protective filling. A fiber optic cable comprising vJ%"4. 2. The filling material is arranged to inhibit the formation of voids within the cable or to inhibit the movement of moisture into the cable. A fiber optic cable according to paragraph 1. 3. A fiber optic cable suitable for use at high voltages, the cable comprising an electrically conductive outer jacket, a reinforcing member and at least one fiber optic element. 4. A fiber optic cable suitable for extending between a high voltage region and a significantly lower voltage region, wherein in the high voltage region the cable has a conductive outer jacket and in the low voltage region the cable has a substantially A fiber optic cable having an outer jacket of electrically non-racking material. 54 A fiber optic cable suitable for use at high voltages, arranged to be connected to ground potential at least at one end thereof. 6. An arrangement comprising a high voltage device and a fiber optic cable adjacent to or in contact with the device, the cable being arranged to be connected at least one end thereof to ground potential. 7. High voltage. 8. A fiber optic cable arrangement suitable for use at high voltage, the cable end being arranged to extend from high voltage to ground potential, the end being provided with environmental protection.8. A fiber optic cable arrangement suitable for use at high voltage, where the cables are arranged so as to extend from high voltage to ground potential, and the cable ends are provided with means to minimize the adverse effects of leakage current flow. 9. An arrangement according to any one of claims 5 to 8, in which the cable is an optical fiber cable according to any one of claims 1 to 4. 10 , high voltage equipment, fiber optic cables arranged outside the conductors in use so as to be exposed to the electric field of the equipment, and on the cables so that any leakage current flowing along the cable jacket is conducted to a point at ground potential. 11. An assembly comprising electrically conductive means mounted on a high voltage conductor, a fiber optic cable d3 arranged outside said conductor to be exposed to the electric field of said conductor, and electrical stress control means. An assembly comprising: an electrical stress resulting from the electric field generated by the conductor and in which the electrical stress to which the cable is exposed is substantially insufficient to cause electrical damage to the fiber optic cable. 12° The stress control means is arranged to surround the fiber optic cable in the region where the cable leaves the immediate vicinity of the conductor's electric field.
Assembly as described in section. 13. The stress control means comprises an electrically conductive housing;
13. An assembly as claimed in claim 11 or 12, in which the cable separates from the conductor in the region of the housing. 14. The assembly of claim 13, wherein the housing is attached to the conductor. 15. An assembly according to claim 13 or 14, wherein the housing has a passageway in which the high voltage conductor is arranged and an outlet through which the fiber optic cable leaves the housing. 16. The assembly of claim 15, wherein the housing has an inlet for the fiber optic cable to enter the housing, the inlet being spaced from the passageway. 17. The housing has a passageway in which a high voltage conductor is disposed and an outlet extending therefrom, the fiber optic cable extending away from the conductor in the passageway and exiting the housing through the outlet. The assembly according to range 13 or 14. 18. The housing according to any one of claims 13 to 17, wherein the housing comprises two half-shells mounted around the conductor and for transversely guiding the optical fiber therefrom. assembly. 19. The housing is divided to receive within the housing a high voltage conductor having a fiber optic cable thereon, and the divisions are secured together by a sealing cap. 18. The assembly according to any of clause 17. 20. An assembly according to any of claims 13 to 19, wherein the housing is externally sealed around the conductor and cable. 21. An assembly according to any one of claims 13 to 17, wherein the housing has an open shape. 22. An assembly according to any of claims 13 to 21, wherein the fiber optic cable is guided away from the housing in the tubular member. 23. An assembly comprising a high voltage conductor and a fiber optic cable arranged to be exposed to the electric field thereof, the cable being loosely disposed within a tubular member and directed away from the conductor by the member. assembly. 24. An assembly according to claim 22 or 23, wherein the tubular member has a convoluted and/or beveled outer surface. 25. The filling material occupies the annular space between the fiber optic cable and the tubular member.
25. The assembly according to any one of items 24 to 25. 26. An assembly according to any of claims 10 to 25, wherein the fiber optic cable extends along the conductor. 27. The assembly of claim 26, wherein the fiber optic cable is spirally wrapped around the conductor. 28. An assembly according to any of claims 13 to 27, further comprising a conductive housing separate from said housing, thereby connecting the fiber optic cable to a lower potential. . 29. Claims 10-27 wherein the fiber optic cable has a substantially electrically conductive non-tracking outer surface
An assembly according to any of paragraphs. 30. Claims 10-2 wherein the portion of the fiber optic cable exposed to the high voltage has an electrically conductive outer surface
9. The assembly according to any of clause 8. 31. The optical fiber cable is defined in claims 1 to 31.
Claim 1 which is stated in any one of Clause 5
29. An assembly according to any one of paragraphs 0 to 28. 32, a first portion of the fiber optic cable is exposed to a high voltage and has an electrically conductive outer surface, the first portion is connected to a second portion of the fiber optic cable, and the second portion is , extending away from the device such that the portion is exposed to the electric field of the high voltage device only to an extent that is substantially insufficient to sustain electrical damage. An assembly according to any of paragraphs 10 to 28. 33. The assembly of claim 32, wherein the outer surface of the second portion of the cable is substantially electrically non-tracking. 34. An assembly according to any one of claims 11 to 33, comprising electrically conductive means according to claim 10. 35. A method of providing electrical protection to fiber optic cables located outside of high voltage equipment and exposed to the electric field of the equipment, wherein in the region where the optical fiber leaves the immediate vicinity of the electric field of the equipment, the cable is mechanical stress control means are provided to ensure that any electrical stress resulting from the electric field generated by the device and to which the cable is exposed is substantially insufficient to cause electrical damage to the fiber optic cable. how to. 36. The method of claim 35, wherein providing the stress control means is accomplished by providing a cable within a conductive housing and arranging the cable to extend from the housing. 37. The method of claim 35 or claim 36, wherein the device combined with an optical fiber cable comprises a long high voltage conductor. 38, the housing has a passageway therethrough and an inlet and an outlet communicating with and spaced from the passageway, the high voltage conductor being disposed through the passageway, and the fiber optic cable being disposed through the passageway; 38. The method of claim 37, arranged in front of the housing and extending away from the conductor and entering the housing through the passage and exiting the housing through the outlet. 39. A method as claimed in claim 37 or 38, in which the housing is divided and mounted by a push fit onto the high voltage conductor. /10. The housing generally has an elongated shape, one end of which is split and the other end with the outlet, the housing being adapted to guide the cable onto the high voltage conductor, between the splits and into the passageway. 40. A method as claimed in claim 39, in which the parts are attached by relative pushing, and the parts are later fixed together. 41. The method according to claim 40, wherein the fixing is performed by mounting a sealing cap on the divided body. 42. The conductive mastic or sealan 1-material is applied to provide an external seal between stress control means on the one hand and high voltage equipment and fiber optic cables on the other hand. 42. The method according to any of Item 41. 43, the tube is fixed to the conductive housing;
Claim 37 and dependent patents thereby extending a fiber optic cable on a high voltage conductor into the housing, away from the conductor within the housing, and out of the housing into the duplex. A method according to any of the claims. 4/1. An optical horn/iber cable exposed to high voltage electrically protected by the method according to any one of claims 35 to 43.