Fiber Insulation with Fiber Optic Cable

Abstract

A fiber insulation (100) is provided with a fiber optic cable (200), the fiber insulation (100) comprising a fiber optic cable (200), a hollow ceramic coating (120) having an overall inner diameter (D) configured to guide the fiber optic cable (200), and an insulating filler (130) at least partially filling the ceramic coating (120) and disposed between the fiber optic cable (200) and the ceramic coating (120), the insulating filler (130) having thermal properties similar to those of the fiber optic cable (200) and the ceramic coating (120), and at least one end of the fiber insulation (100) is closed by at least one end cap (151, 152).

Description

[Technical field]

[0001] FIELD OF THE PRESENT ART The present invention relates to a fiber insulation with fiber optic cable for use in direct measurement applications in medium and high voltage cut-off disconnect switches.

[0002] prior art Signal and / or data transmission in controlled (indoor) high voltage environments can already be done via optical fibers. To bridge the gap of large potential differences, certain coating materials are available. Furthermore, these materials are mainly used in inner areas such as transformers (closed environments), valve chambers (closed humidity controlled environments), etc.

[0003] The transmission of optical fiber signals and data in medium and high voltage environments can be carried out by so-called fiber insulators. The main application in practice can be found in long-distance fiber transmission in combination with high-voltage lines. Thus, so-called ADSS cables are used to transmit optical fiber telecommunication signals. At the start and end of the high-voltage line, a fiber connection to ground level is required. This can be done via various fiber insulators to bridge the gap up to 1200 kV. Nevertheless, these are fixed installations, which means that there is no significant movement of the associated insulators themselves.

[0004] Another application of fiber insulation can be found in medium and high voltage substations and high voltage substations, where various different devices have to be connected to the optical fiber signal transmission. All these applications are fixed installations and do not move. Such movements can cause mechanical shock effects on the optical signal.

[0005] In the medium and high voltage area, signals and data must be transmitted in optical fibers from the measuring points to the main control cabinet at ground level, which can be done either by wireless data transmission or by wired signal and data transmission.

[0006] technical challenges For wireless transmission, the main challenge is to provide power for the sensor system and to maintain an uninterrupted connection in all weather conditions. Another challenge is the difficulty and acceptance of a self-powered system in this high voltage environment. Therefore, this method has its limitations.

[0007] Standard copper-based sensor solutions are not applicable due to the potential difference between the sensor and the receiving electronics (ground level to 50 kV at the sensor location), so the only option is to use optical fiber-based data and signal transmission.

[0008] An additional challenge is the outdoor and harsh environment in which disconnectors are typically located, which may have temperatures ranging from minus 50 degrees Celsius to plus 85 degrees Celsius. Additionally, humidity, sand, mud, heavy rain and thunderstorms, air pollution and other adverse environmental factors must be considered.

[0009] Pure cable connections at levels (potential differences) above 50 kV from ground level are problematic, for example, due to partial discharge and leakage currents as well as environmental factors.

[0010] It has been found by the inventors of the present invention that partial discharges occur in almost all cables in such environments after a certain lifespan, mainly due to aging of the cable material and residues / deposits from environmental influences (e.g. air pollution, moss, etc.).

[0011] Cable connections can be made using so-called fiber insulations, i.e. hollow insulations made from ceramic or silicone. Silicone insulations face some technical problems, as described in publicly available studies. Nevertheless, they may be the best choice in combination with cables in terms of manufacturing challenges, shrinkage, etc. To overcome such difficulties, conventional ceramic insulations in combination with fiber feedthroughs may be the preferred option.

[0012] The third and most difficult difficulty to overcome is that the switch contains moving parts, in particular the insulator itself, which moves and rotates with the connecting arm of the Breaking-closing disconnecting switch (BCDS) to perform the on-off function. This leads to significant repeated twisting in the optical fiber during its use for signal and data transmission. In a normal cable, this twisting can have a significant effect on the optical performance of the fiber, adversely affecting its detection signal.

[0013] Based on this fact, both cables and their connections to the insulation must be developed that are resistant to tension and bending.

[0014] solution Developed by the inventors of the present invention is a fiber insulator with fiber optic cable for reliable, high performance signal and data transmission for the life of a medium and high voltage (disconnect) switch.

[0015] According to the present invention, one or more of the above mentioned problems are solved by a fiber insulation with a fiber optic cable as defined by the independent claim 1. Particular embodiments are further defined by the dependent claims.

[0016] According to one embodiment of the present invention, a fiber insulation with a fiber optic cable is provided, the fiber optic cable having a fiber optic cable and a hollow ceramic coating. The ceramic coating has an inner overall diameter configured to guide the fiber optic cable. The fiber insulation further includes an insulating filler at least partially filling the ceramic coating and disposed between the fiber optic cable and the outer ceramic coating. Furthermore, at least one end of the fiber insulation is closed by at least one end cap configured to close the at least one end of the fiber insulation, the at least one end cap configured to allow the fiber optic cable to pass through the at least one end cap.

[0017] Preferably, at least one end cap is configured to be secured to an outer surface or outer layer of the optical fiber cable, such as a yarn covering a (hollow) tube of the optical fiber cable or a non-corrosive coating covering the yarn, thereby preventing movement of the optical fiber cable along the extension direction of the optical fiber cable and / or reducing / preventing twisting transmitted to the fibers of the optical fiber cable and applied to the optical fiber cable.

[0018] The insulating filler material can fill most, and preferably completely, the hollow interior space between the fiber optic cable and the hollow ceramic coating.

[0019] The ceramic coating may have an overall inner diameter configured to guide the fiber optic cable, i.e., the ceramic coating may extend along the extension direction to cover a predetermined length of the fiber optic cable. The fiber optic cable may be fed into the hollow ceramic coating through at least one end cap, and the fiber optic cable may be guided along the extension direction by the ceramic coating.

[0020] The extension direction of the fiber insulation / ceramic coating may be at least partially the same as or different from the extension direction of the optical fiber cable.

[0021] In this specification, an end of a fiber insulation should be understood as either the beginning or the end of the fiber insulation when viewed along the extension direction of the fiber insulation, and the fiber insulation may extend from one end to another end thereof.

[0022] In order to achieve improved performance and insulating function of fiber insulation in the above-mentioned harsh environments, hollow ceramic coatings as described above are proposed, and the inner space of the insulation may be filled with a filling material or may be completely filled.

[0023] The insulating material may have thermal properties configured to compensate for the thermal properties of at least one of the fiber optic cable and the ceramic coating. Preferably, the insulating material may have thermal properties configured to compensate for the thermal properties of both the fiber optic cable and the ceramic coating. In other words, the insulating material may have thermal properties configured to prevent temperature changes and / or high / low temperatures due to the environment of the fiber insulation from being conducted through the insulating material to the fiber optic cable to prevent any damage and effects of temperature changes and / or high temperatures (e.g., below 0° C. or above 100° C.) on the fiber optic cable or the fibers of the fiber optic cable.

[0024] Additionally, at least one end, and preferably both ends, of the insulator may be closed with an end cap to protect the filler material and to facilitate the filling process.

[0025] The outer surface of the ceramic coating may have a corrugated shape, and the inner surface of the ceramic coating may face the optical fiber cable. Furthermore, the inner surface of the ceramic coating may have a smooth surface extending along the extension direction of the fiber insulation. This provides the technical effect that the creepage distance can be significantly increased compared to a smooth outer surface (smooth lobe). The long creepage distance contributes to the insulation level of the fiber insulation.

[0026] The insulating filler may have thermal properties similar to those of the fiber optic cable and the ceramic coating, thereby providing improved insulating functionality.

[0027] At least one end cap may be configured to seal an end of the insulator, thereby providing environmental protection.

[0028] As used herein, sealing function has its general meaning within the state of the art of sealing, e.g., the ability to seal an opening in an insulator such that fluids and / or gases cannot pass through the seal, thus sealing the insulator against fluids or gases that would otherwise pass through or exit from inside the insulator.

[0029] At least one end cap may have a fiber optic cable opening that can be positioned to allow the fiber optic cable to pass through the fiber optic cable opening and into the fiber insulation (and into the hollow coating). Optionally, the fiber optic cable opening can be configured to be sealed by the fiber optic cable as it passes through the fiber optic cable opening.

[0030] The at least one end cap is removably coupleable to at least one end of the fiber insulation.

[0031] By providing at least one end cap, the filler material can be first filled into the ceramic coating through the at least one end, and after filling the filler material, the end cap can be placed on or in the at least one end to prevent the filler material from coming out of the insulation and protect the filler material. Furthermore, by appropriately selecting the diameters of the at least one end and the at least one end cap, an efficient filling process can be achieved compared to, for example, the case where the filler material is put in through an optical fiber opening having a smaller diameter compared to the diameter of the at least one end cap.

[0032] The end of the insulator may have a square-shaped shape when viewed in a cross-section extending along the extension direction of the fiber insulator. When viewed in this cross-section, the square-shaped shape may have a front surface and a rear surface parallel to the front surface, said front surface and rear surface being connectable by a side. When viewed in this cross-section, there may be two side surfaces connecting the front surface and the rear surface. Naturally, when viewed three-dimensionally, there may be at least four side surfaces connecting the front surface and the rear surface. The fiber insulator may extend from the front surface of the square-shaped shape along the extension direction. In other words, when viewed along the extension direction, the fiber insulator may have a first end and a second end. The fiber insulator may extend from the first end to the second end. The first end may correspond to the front surface, and the second surface may be located between the first end and the second end. Furthermore, when viewed in the cross-section, the front surface and the rear surface of the square-shaped shape may extend along a direction perpendicular to the extension direction. At least one edge formed by one side and the front or rear face may be configured as an opening arranged to receive at least one end cap. Optionally, the opening of the square shaped portion may be sealed by or with at least one end cap.

[0033] In other words, the square-shaped profile may be hollow and said inner hollow space may be connected to the inner space of the hollow ceramic coating, and openings formed in the edges may connect the hollow space of the square-shaped profile with the environment of the fiber insulation.

[0034] Here, the term "edge of the square feature" is used to designate the location of an opening configured to receive at least one end cap. Of course, when an edge is configured as an opening, said edge no longer physically exists.

[0035] At least two edges of the square-like feature may be configured with openings, each opening configured to receive a respective end cap.

[0036] The two openings may be connected to an inner hollow space of the square shaped portion.

[0037] When viewed in cross section, at least two openings of the square shaped portion can be formed in edges corresponding to the side faces that connect to the front face.

[0038] By providing at least two openings sealed by respective end caps, the fiber optic cable can be fed through a first end cap without the filler material already being introduced into the hollow jacket. The fiber optic cable can be positioned as desired and one opening is sealed with the fiber optic cable by the corresponding end cap. The second opening can then be used to fill with the filler material and then the second opening can be sealed after being at least partially or completely filled by the second end cap. This facilitates assembly of the insulator and the fiber optic cable.

[0039] The filling material can at least partially fill both the hollow ceramic coating and the hollow space of the square profile, thereby ensuring the insulating effect of the insulation on the optical fiber cable.

[0040] The optical fiber cable may have a hollow tube extending along a fiber cable extension direction, at least one fiber extending along the fiber cable extension direction and disposed within the hollow tube, and a special gel disposed in the hollow tube, the special gel being disposed at least partially between the at least one fiber and the hollow tube when viewed in a cross section extending perpendicular to the fiber cable extension direction. The hollow tube may have at least a first portion and a second portion. The first portion of the hollow tube may be disposed inside the fiber insulation, and the second portion may be disposed outside the fiber insulation. The second portion may extend (along the optical fiber cable extension direction) from the at least one end cap away from the at least one end cap. The outer surface of the second portion of the hollow tube may be covered by a high resistance aramid yarn. The outer surface of the high resistance aramid yarn may be covered by a polyurethane, polyethylene or cross-linked polyethylene / flame-retardant non-corrosive coating.

[0041] The fiber optic cable opening or at least one end cap may be configured to fix the second portion of the hollow tube. The fiber optic cable opening or at least one end cap may be configured to be fixed by the high resistance aramid yarn and / or the non-corrosive coating. That is, the second portion of the hollow tube may have the high resistance aramid yarn and the non-corrosive coating, and the end disposed in the fiber optic cable opening or at least one end cap may be fixed to the fiber optic cable opening or the last one end cap. In other words, the coating and the aramid yarn may be fixed to the end of the fiber insulation by the cable gland and in or at the at least one end cap.

[0042] The aramid yarn and non-corrodible coating must be removable or absent in the first portion since the aramid yarn may become a voltage carrying medium if immersed in water.

[0043] By fixing the second portion of the hollow tube and / or the fiber optic cable opening / at least one end cap to the high resistance aramid yarn and / or the non-corrosive coating, for example, any tensile forces applied to the fiber optic cable can be applied to the aramid yarn, the non-corrosive coating, and the at least one end cap and / or the fiber optic cable opening of the at least one end cap, but not to the fiber, which can further improve the signal quality of the fiber optic cable in applications where such forces are applied or where the fiber optic cable moves.

[0044] The use of coatings of the named materials can provide fiber optic cables that can withstand required environmental influences.

[0045] Additionally, the inclusion of high resistance aramid yarns can improve the mechanical performance of the fiber optic cable, particularly by providing improved elongation and crust strength, which in turn provides the fiber optic cable with increased strength and resistance to repeated bending and twisting.

[0046] By providing a special gel inside the hollow tube between the at least one fiber and the hollow tube, the movement of the hollow tube can be attenuated or even decoupled from the movement of the at least one fiber. Because the optical signal transmitted through the at least one fiber is highly sensitive to any movement of the at least one fiber, and to reduce or even eliminate noise or degradation of the transmitted optical signal, a special gel can be provided between the hollow tube and the at least one fiber. The special gel can absorb or attenuate any movement of the hollow tube without transmitting the movement to the at least one fiber. Thus, such a fiber optic cable can be used in applications where the fiber optic cable needs to be moved without degrading the optical signal.

[0047] The hollow tube may be a loose tube. In particular, the second portion of the hollow tube may be a loose tube.

[0048] The special gel may have a particular speed configured to only partially transmit the movement and / or rotation of the hollow tube to the at least one fiber, or the special speed can be configured to decouple the movement and / or rotation of the hollow tube from the movement of the at least one fiber.

[0049] The special gel may have a particular viscosity that is configured to prevent it from moving or dripping at the end of the optical fiber cable, even if the optical fiber cable is positioned in a position where the optical fiber cable extends in a direction parallel to the Earth's gravitational force.

[0050] In other words, the viscosity of the special gel can be set so that the fiber optic cable can be held vertically without the special gel moving or dripping at the end of the fiber optic cable.

[0051] The hollow tube can be made of a dual layer hollow tube. The dual layer can be polycarbonate and polybutylene terephthalate. This allows the fiber optic cable to be used in different temperature ranges. Alternatively, the hollow tube can be made of polyamide, ethylene tetrafluoroethylene or polybutylene terephthalate. Polybutylene terephthalate is a suitable material for mild environments such as those in Europe.

[0052] The hollow tube may be a loose hollow tube.

[0053] High resistance aramid yarns can provide the necessary tensile, bending and torsional performance of fiber optic cables.

[0054] According to another embodiment of the present invention, there is provided a system having an insulation according to any of the aspects of the insulation described above. The fiber optic cable of the system or provided with the system may be a fiber optic cable according to any of the aspects of the fiber optic cable described above.

[0055] The following drawings illustrate the present disclosure: [Brief description of the drawings]

[0056] [Figure 1] 1 is a cross-sectional view of a fiber insulation according to the present invention; [Diagram 2] 1 is a cross-sectional view of a fiber optic cable according to the present invention. [Diagram 3] 1A-1D are cross-sectional, side and top views of an exemplary application of fiber insulation and fiber optic cable.

[0057] The following description of the drawings is used for illustrative purposes and should not be construed as limiting the claims and scope of the present invention to their specific details. Furthermore, the dimensions and sizes of the drawings do not necessarily correspond to reality and are drawn for illustrative purposes.

[0058] In Fig. 1, a cross-sectional view of a fiber insulation 100 according to the invention is shown. This cross-sectional view extends in the plane of the drawing. The fiber insulation 100 comprises an optical fiber cable 200, a ceramic coating 120 and an insulating filler 130. The optical fiber cable has the reference number 200 in Fig. 1, but the optical fiber cable 200 in Fig. 1 may have a different configuration than the optical fiber cable shown in Fig. 2. Of course, this optical fiber cable may be the optical fiber cable 200 described with reference to Fig. 2.

[0059] The ceramic coating 120 is hollow and has an overall inner diameter D configured to guide the optical fiber cable 200 along the extension direction of the fiber insulation 100 or the optical fiber cable 200. As is clear from FIG. 1, the diameter D of the ceramic coating 120 is set to be larger than the diameter of the optical fiber cable 200 so that the optical fiber cable 200 can be fed through the fiber insulation 100. In particular, the diameter D of the ceramic coating 120 is set so that the insulating filler 130 can be filled into the hollow ceramic coating 120 and can be placed between the optical fiber cable 200 and the ceramic coating 120. The insulating material 130 is electrically insulating, and the insulating filler 130 has thermal properties configured to compensate for at least one thermal property of the optical fiber cable 200 and the ceramic coating 120. That is, the thermal properties of the insulating material 130 are set / configured such that the thermal properties can compensate for the heat that is conducted or absorbed by the ceramic coating 120 that is not transferred to the optical fiber cable 200, for example. In other words, the thermal properties of the insulating material 130 can be configured to be thermally insulating.

[0060] The insulating filler 130 may be a material that may be initially provided in a fluid or gel state to be filled into the ceramic jacket 120. Once the fiber optic cable 200 and the insulating filler 130 are provided inside the ceramic jacket 120, the insulating filler 130 may harden and become a long-term stable and electrically and temperature insulating part of the fiber insulation 100. Additionally, at least one end of the fiber insulation 100 is closed by at least one end cap 151, 152.

[0061] By providing the insulating filler 130 at least partially inside the ceramic coating 120 and by disposing the insulating filler 130 at least partially between the optical fiber cable 200 and the ceramic coating 120, the insulating performance of the fiber insulation 100 is improved and any optical signals transmitted through the optical fiber cable 200 can be shielded against disruptive environmental influences, such as high voltage environments.

[0062] 1, the outer surface of the ceramic coating 120 has a corrugated shape, and the inner surface of the ceramic coating 120 faces the optical fiber cable 200. In particular, the inner surface of the ceramic coating 120 has a smooth surface, which can facilitate the feeding of the optical fiber cable 200 and improve the filling process of the insulating filler material 130. This increases the creepage distance compared to a smooth outer surface (smooth lobe), and this relatively long creepage distance contributes to the insulation level of the insulator 100.

[0063] 1, the optical fiber cable 200 or its hollow tube 210 has a first portion 211 and a second portion 212. The first portion 211 is disposed within the fiber insulation 100, particularly within the ceramic coating 120. The second portion 212 is disposed outside the fiber insulation 200. As shown in FIG. 1, the second portion 212 extends from the at least one end cap 151 to the bottom of FIG. 1 along the extension direction of the optical fiber cable 200. Thus, the second portion 212 extends away from the at least one end cap 151.

[0064] 1, the second portion 212 extends from an outer surface of the at least one end cap 151. The first portion 211 extends from an inner surface of the at least one end cap 151 opposite the outer surface and at least along the inner surface of the ceramic coating 120.

[0065] 1 shows only the lower portion of the fiber insulation 100 and its corresponding lower end. Of course, the fiber insulation 100 may have an upper portion that may be configured identically to the lower end shown in FIG. 1, and that also includes the end of the fiber insulation 100.

[0066] At least one end of the fiber insulation 100 has a square shape in FIG. 1. In particular, FIG. 1 shows a rectangular shape of at least one end of the fiber insulation 100. The square shape is hollow and connected to the internal space of the hollow ceramic cladding 120. Furthermore, the square shape has a front surface, a rear surface and two side surfaces in the cross-sectional view of FIG. 1. Of course, when viewed three-dimensionally, at least four side surfaces are provided. The front surface and the rear surface are connected by two side surfaces to form a square shape. Furthermore, the front surface and the rear surface of the square shape extend perpendicularly to the extension direction of the fiber insulation 100. As is clear from FIG. 1, the front surface and the rear surface of the square shape extend beyond the corrugated shape of the ceramic cladding 120.

[0067] Furthermore, the square shape has two openings 141, 142 formed at the lower corners / edges of the square shape as seen in FIG. 1. Each opening 141, 142 may be provided with an end cap 151, 152. The end cap 151, 152 may be configured to close and optionally seal the opening 141, 142, thereby protecting the insulating filler material 130 and enabling the filling process. The fiber optic cable 200 passes through the fiber optic cable opening of the end cap 151. The configuration of the fiber insulation according to FIG. 1 allows for an easy and time-efficient assembly of the fiber insulation 100. That is, the fiber optic cable 200 can be fed through the fiber optic cable opening of the end cap 151 and thus can be easily positioned in the fiber insulation 100. That is, the fiber optic cable 200 can be easily threaded through the cap 151 and pulled into the fiber insulation 100, while the end cap 151 maintains its position in the opening 141 during the pulling of the fiber optic cable. Then, another opening 142 can be used to fill the insulating filler 130 before or after placing the optical fiber cable 200. The opening 142 can have a larger diameter than the optical fiber cable 200 and still be sealed or closed by the end cap 152, thus realizing an efficient filling process. Also, the openings 141 and 142 are connected to the entire inner space of the square shape, so that the optical fiber cable 200 can pass through the entire inner space and the insulating filler 130 can be introduced.

[0068] The end caps 151 , 152 can be configured to seal the openings 141 , 142 with or without the fiber optic cable 200 .

[0069] At least one end cap 151, 152 may be configured as a plug for closing at least one end of the fiber insulation 100. In particular, at least one end cap 151, 152 may have a disk or plug-like shape having a radius corresponding to or slightly smaller than the radius of the openings 141, 142.

[0070] In Fig. 2, a cross-sectional view of the optical fiber cable 200 according to the invention is shown. The cross-sectional view of Fig. 2 is perpendicular to the cross-sectional view of Fig. 1 and is a cross-sectional view of the optical fiber cable 200 at the second section 211. The optical fiber cable 200 comprises a hollow tube 210 extending along a fiber cable extension direction as previously shown with respect to Fig. 1. The optical fiber cable 200 further comprises at least one fiber 220 extending along a fiber cable extension direction, where the at least one fiber 220 is arranged in the hollow tube 210. There may be more than one fiber 220 inside the hollow tube 201. Furthermore, a special gel 230 is arranged at least partially inside the hollow tube 210 and between the at least one fiber 220 and the hollow tube 210. The outer surface of the second section 211 of the hollow tube 210 is covered by a high resistance aramid yarn 240, and the inner surface of the hollow tube 210 faces the at least one fiber 220. Cross-linked Polyethylene Furthermore, the exterior surface of the high resistance aramid yarn 240 is covered with a polyurethane, polyethylene, or cross-linked polyethylene / flame retardant non-corrosive coating 250 .

[0071] By placing the special gel 230 inside the hollow tube 210, and in particular between the fiber optic cable 200 and the inner surface of the hollow tube 210, any movement of the hollow tube 210 can be damped, so that less or no movement is transmitted through the special gel 230 to the at least one fiber 220. In other words, due to the speed of the special gel 230, any movement of the hollow tube 210 can be decoupled or damped from the movement of the at least one fiber 220. This is beneficial, since any small movement or vibration applied to the at least one fiber 220 can affect the transmitted optical signal and can degrade the optical signal. By reducing or even eliminating said shocks, it is possible to perform highly sensitive measurements and transmit the corresponding optical signal through the fiber optic cable 200 without or with less degradation of reception at the corresponding measurement point.

[0072] In particular, the velocity of the special gel 230 may be configured or set to a velocity that only partially transmits the movement and / or rotation of the hollow tube to the at least one fiber 220. Additionally, the special gel 230 has a velocity that is configured so that it does not move or drip off at the fiber optic cable end, even if the fiber optic cable 200 is positioned in a position where the fiber optic cable 200 extends in a direction parallel to the gravitational force of the Earth.

[0073] The hollow tube 210 can be made of a double layer hollow tube that is polycarbonate and polybutylene terephthalate. Alternatively, the hollow tube 210 can be made of polyamide, ethylene tetrafluoroethylene, or polybutylene terephthalate. For mild environments such as in Europe, polybutylene terephthalate can be used.

[0074] Additionally, hollow tube 210 may be configured as a loose hollow tube, i.e., hollow tube 210 may rest in a loose configuration rather than being taut between the two ends of the fiber optic cable, which may be beneficial for further dampening movement of fiber optic cable 200.

[0075] 1, the second portion 211 of the fiber optic cable 200, consisting of the hollow tube 210, at least one fiber 220, special gel 230, high resistance aramid yarn 240, and non-corrosive coating 250, is secured to at least one end cap 151. In particular, at least the high resistance aramid yarn 240 and the non-corrosive coating 250 are secured to the at least one end cap 151.

[0076] By fastening only the high resistance aramid yarns 240 and the non-corrosive coating 250, for example, whereas the hollow tube 210 can be considered a loose tube, tension applied to the fiber optic cable 200 is applied to the high resistance aramid yarns 240 and the non-corrosive coating 250, and not to the loose tube, and in particular to the fiber 220. The tension is directed to the at least one end cap 151, and not to the fiber insulation 100. Thus, the fiber 220 is protected from external forces applied to the fiber optic cable 200, which would otherwise shorten or deteriorate, thereby increasing the life of the fiber optic cable and preserving the transmission properties of the fiber 220.

[0077] In Fig. 3 three different views are shown, namely a cross-section, a side view and a top view of an exemplary application of the invention. In the cross-section the fiber insulation 100 according to Fig. 1 is shown together with a fiber optic cable 200. In the side view the fiber insulation 100 is shown with an arm 320 of a break-close disconnector (BCDS) arranged at the upper end of the fiber insulation 100. The fiber optic cable 200 is connected to a measurement point 310 and passes through the lower end of the fiber insulation 100. The fiber optic cable 200 is guided by the fiber insulation 100 to the upper end and is fed through the arm 320 to the optical measurement position. Furthermore, as exemplarily shown in the side view, in this environment a voltage V1 is applied at the upper end of the fiber insulation 100 at the optical measurement position. Also in this environment a voltage V2 is present at the lower end. The difference between voltages V1 and V2 may be between 50 kV and 250 kV. As shown as an example in the side view a rotation direction arrow T is shown. See also the top view. Such optical measurements may require moving or rotating the arm 320 to another measurement position or off position. When the arm 320 rotates as indicated by the arrow T, a twist is also applied to the fiber optic cable 200. It has already been explained above that the optical signal transmitted through the fiber optic cable 200 may be highly sensitive, and such twisting may in turn degrade the optical signal. Since the fiber optic cable 200 may be configured as the fiber optic cable 200, the adverse effects of twisting can be reduced through the special gel 230. Thus, the optical measurement device having the fiber insulation 100 and the fiber optic cable 200 can be moved without degrading the optical signal.

Claims

1. A fiber insulation (100) comprising a fiber optic cable (200), the fiber insulation (100) comprising: A fiber optic cable (200); A hollow ceramic coating (120), a ceramic coating (120) having an overall inner diameter (D) configured to guide said optical fiber cable (200); an insulating filler (130) at least partially filling the ceramic coating (120) and disposed between the optical fiber cable (200) and the ceramic coating (120); At least one end of the fiber insulation (100) is closed by at least one end cap (151, 152) configured to close at least one end of the fiber insulation (100); At least one of the end caps (151, 152) is configured such that the optical fiber cable (200) passes through the at least one end cap; At least one of the end caps (151, 152) is configured to fix the optical fiber cable (200) such that movement of the optical fiber cable (200) along an extension direction of the optical fiber cable is prevented; The optical fiber cable (200) comprises: A hollow tube (210) extending along the fiber cable extension direction; At least one fiber (220) extending along the fiber cable extension direction and disposed within the hollow tube (210); a special gel (230) disposed within the hollow tube (210), the special gel (230) being at least partially disposed between at least one of the fibers (220) and the hollow tube (210); The hollow tube (210) has at least a first portion (211) and a second portion (212); the first portion (211) of the hollow tube (210) is disposed inside the fiber insulation and the second portion (212) is disposed outside the fiber insulation, the second portion (212) extending from the at least one end cap along the fiber cable extension direction away from the at least one end cap; the outer surface of the second portion (212) of the hollow tube (210) is covered with a high resistance aramid yarn (240); The outer surface of the high resistance aramid yarn (240) is covered with a flame-retardant, non-corrosive coating (250) made of polyurethane, polyethylene, or cross-linked polyethylene; a fiber optic cable opening configured to secure the second portion of the hollow tube (210); The fiber optic cable opening is configured to be secured by the high resistance aramid yarn and / or the flame retardant, non-corrosive coating (250), i.e., by securing at least one of the end caps at the fiber optic cable opening to the high resistance aramid yarn and / or the flame retardant, non-corrosive coating.

2. The fiber insulation (100) of claim 1, wherein an outer surface of the ceramic coating (120) has corrugated features and an inner surface of the ceramic coating (120) faces toward the fiber optic cable (200).

3. The fiber insulation (100) of claim 1 or 2, wherein the insulating filler (130) has thermal properties configured to compensate for at least one thermal property of the optical fiber cable (200) and the ceramic coating (120).

4. The fiber insulation (100) of any one of claims 1 to 3, wherein at least one of the end caps (151, 152) is configured to seal at least one of the ends of the fiber insulation (100).

5. At least one of the end caps (151, 152) has the fiber optic cable opening, and the fiber optic cable opening is arranged so that the fiber optic cable (200) passes through the fiber optic cable opening and into the fiber insulation (100); Optionally, the fiber optic cable opening is configured to be sealed by the fiber optic cable when the fiber optic cable passes through the fiber optic cable opening.

6. At least one of the ends of the fiber insulation (100) has a square shape when viewed in a cross section along the extension direction of the fiber insulation (100), When viewed in cross section, the square shaped portion has a front surface and a rear surface parallel to the front surface, the front surface and the rear surface being connected by a side surface; The fiber insulation (100) extends from the front surface of the square shaped portion along the extension direction, When viewed in cross section, the front and rear faces of the square shaped portion extend along a direction perpendicular to the extension direction, At least one edge formed by one of the side faces and the front or rear face is configured as an opening (141, 142) arranged to receive at least one of the end caps (151, 152); 6. The fiber insulation (100) according to any one of claims 1 to 5, optionally wherein said openings (141, 142) of said square shaped portion are sealed by at least one said end cap (151, 152).

7. 7. The fiber insulation (100) of claim 6, wherein at least two edges of the square-shaped portion are configured as openings (141, 142) configured to receive at least one respective end cap (151, 152).

8. 8. The fiber insulation (100) of claim 7, wherein, when viewed in cross section, at least two of the openings (141, 142) of the square-shaped portion are formed in the edge corresponding to the side surface connected to the front surface.

9. the special gel (230) has a specific viscosity configured to only partially transmit the movement and / or rotation of the hollow tube (210) to at least one of the fibers (220), the specific viscosity being configured to decouple the movement and / or the rotation of the hollow tube (210) from the movement of at least one of the fibers (220); and / or The fiber insulation (100) of any one of claims 1 to 8, wherein the special gel (230) has a specific viscosity configured so as not to move or drip at the end of the optical fiber cable, even if the optical fiber cable (200) is placed in a position where the optical fiber cable (200) extends in a direction parallel to the gravitational force of the earth.

10. the hollow tube (210) is formed from a double layer hollow tube of polycarbonate and polybutylene terephthalate; or The fiber insulation (100) of any one of claims 1 to 9, wherein the hollow tube (210) is formed from a polyamide, ethylene tetrafluoroethylene or polybutylene terephthalate.

11. The fiber insulation (100) of any one of claims 1 to 10, wherein the hollow tube (210) is a loose hollow tube.

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