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EP-3579251-B1 - SHATTER PROTECTION

EP3579251B1EP 3579251 B1EP3579251 B1EP 3579251B1EP-3579251-B1

Inventors

  • HORTLUND, STEFAN
  • HENRIKSSON, MAGNUS
  • HOLMBERG, ANDERS
  • JOHANSSON, Andre

Dates

Publication Date
20260506
Application Date
20180605

Claims (13)

  1. A shatter protection (1) for a high voltage apparatus (2) with a ceramic insulator (3), wherein the shatter protection (1) comprises a first electrically insulating tube (41) the first electrically insulating tube comprising an envelope surface having a plurality of holes (51) going through the envelope surface of the first electrically insulating tube (41) the first electrically insulating tube (41) hasa diameter configured such that there is a minimum distance between the first electrically insulating tube (41) and the ceramic insulator (3) when the shatter protection (1) and the ceramic insulator (3) are arranged concentrically, and characterized in that : the first electrically insulating tube (41) comprises two layers of helically wound electrically insulating fiber composite material, wherein one of the layers comprises a first helix shape of the electrically insulating fiber composite material wound with a first pitch such that there is a first gap between the winding turns, and the other layer comprises a second helix shape of the electrically insulating fiber composite material wound onto the first helix shape, the winding of the second helix shape is in the opposite direction as the winding of the first helix shape and it is wound at a second pitch, which is different from the first pitch, and such that there is a second gap between the winding turns, whereby the plurality of holes (51) of the first electrically insulating tube (41) are formed by the first and second gaps between the winding turns.
  2. The shatter protection (1) according to claim 1, comprising at least two electrically insulating tubes (41, 42) with different diameters and which are arranged concentrically with a distance (6) between them.
  3. The shatter protection (1) according to claim 2, and wherein the holes (51,52) of the at least two electrically insulating tubes (41, 42) are arranged such the shatter protection (1) is closed seen from a centerline of the concentrically arranged electrically insulating tubes and radially outwards.
  4. The shatter protection (1) according to any preceding claim, wherein the holes (5) through the envelope surface are arranged and shaped to increase the creepage distance (7) between the ends (4a, 4b) of the electrically insulating tube (4, 41, 42).
  5. The shatter protection (1) according to any preceding claim, comprising a second electrically insulating tube (42) with a different diameter than the first electrically insulating tube (41), the first and the second electrically insulating tubes (41, 42) are arranged concentrically with a distance (6) between them, wherein the second electrically insulating tube (42) comprises two layers of helically wound electrically insulating fiber composite material, wherein one of the layers comprises a third helix shape of the electrically insulating fiber composite material wound at a third pitch such that there is a third gap between the winding turns, and the other layer comprises a fourth helix shape of the electrically insulating fiber composite material wound onto the third helix shape, the winding of the fourth helix shape is in the opposite direction as the winding of the third helix shape and it is wound at a fourth pitch, which is different from the third pitch, such that there is a fourth gap between the winding turns.
  6. The shatter protection according to any one of the preceding claims, wherein the electrically insulating fiber composite material comprises an inorganic fiber reinforced polymer material.
  7. The shatter protection according to any one of claims 1-5, wherein the electrically insulating fiber composite material comprises an organic fiber reinforced polymer material.
  8. A high voltage apparatus (2) comprising a ceramic insulator (3) and a shatter protection (1) according to any of claims 1 to 7, wherein there is a minimum distance between the electrically insulating tube (4, 41, 42) and the ceramic insulator (3) when the shatter protection (1) and the ceramic insulator (3) are arranged concentrically.
  9. Method for producing a shatter protection (1) for a high voltage apparatus (2) with a ceramic insulator (3), the shatter protection (1) comprises at least one electrically insulating tube (4, 41, 42) comprising an electrically insulating fiber composite material, the method comprises: • winding (S1) a first helix shape of the electrically insulating fiber composite material at a first pitch such that there is a first gap between the winding turns, the diameter of the first helix shape is such that there is a minimum distance between the first helix shape and the ceramic insulator (3) when a first electrically insulating tube (4, 41) and the ceramic insulator (3) are arranged concentrically; and • winding (S2) a second helix shape of the electrically insulating fiber composite material onto the first helix shape, the winding of the second helix shape is in the opposite direction as the winding of the first helix shape and it is wound at a second pitch, which is different from the first pitch, and such that there is a second gap between the winding turns; and thereby forming the first electrically insulating tube (4, 41) of the at least one electrically insulating tube (4) with holes (51) formed by the first and second gap between the winding turns.
  10. The method according to claim 9, wherein the shatter protection (1) comprises at least two electrically insulating tubes and the method comprises: • winding (S3) a third helix shape of the electrically insulating fiber composite material at a third pitch such that there is a third gap between the winding turns, the diameter of the third helix shape is such that there is a distance (6) between the first electrically insulating tube (41) and the third helix shape when the third helix shape and the first electrically insulating tube (41) are arranged concentrically; and • winding (S4) a fourth helix shape of the electrically insulating fiber composite material onto the third helix shape, the winding of the fourth helix shape is in the opposite direction as the winding of the third helix shape and it is wound at a fourth pitch, which is different from the third pitch, and such that there is a fourth gap between the winding turns; and thereby forming a second electrically insulating tube (42) of the at least one electrically insulating tubes (4) with holes (52) formed by the third and fourth gap between the winding turns, and: • arranging (S5) the first electrically insulating tube (41) and the second electrically insulating tube (42) concentrically.
  11. The method according to claim 10, wherein arranging (S5) the first electrically insulating tube (41) and the second electrically insulating tube (42) concentrically comprises arranging (S5a) them such that the holes (51, 52) of the electrically insulating tubes (41, 42) are arranged such that the shatter protection (1) is closed seen from a centerline of the concentrically arranged electrically insulating tubes (41, 42) and radially outwards.
  12. The method according to claim 10, wherein the first pitch, the second pitch, the third pitch and the fourth pitch are chosen such that the holes (51) of the first electrically insulating tube (41) and the holes (52) of the second electrically insulating tube (42) are arranged such the shatter protection (1) is closed seen from a centerline of the concentrically arranged electrically insulating tubes (41, 42) and radially outwards.
  13. The method according to claim 10, wherein the first pitch and the third pitch are the same and wherein the second pitch and the fourth pitch are the same and wherein the step of arranging (S5) the first electrically insulating tube (41) and the second electrically insulating tube (42) concentrically comprises rotationally offsetting (S5b) the first and the second electrically insulating tubes around the centerline of the electrically insulating tubes (41, 42) with respect to each other such that the holes (51, 52) do not overlap and the shatter protection (1) is closed seen from a centerline of the concentrically arranged electrically insulating tubes (41, 42) and radially outwards.

Description

Technical field The present invention relates to a shatter protection for a high voltage apparatus with a ceramic insulator. Background Although there is an increased use of composite insulators, there are still a very large number of porcelain insulators in use. Faults in HV apparatuses with porcelain insulators often results in explosion and porcelain fragments flying at high speed in all directions; which pose a danger for personnel and neighboring equipment. Explosive failures of this type can be due to internal failures that cause sudden heating and expansion of the internal insulation medium (gas or liquid). Explosive failures can also be due to vandalism. Present risk mitigations include: Prevent personnel from accessing stations with energized equipment at risk.Replace equipment at risk with new and safer equipment, e.g. dry HV apparatuses instead of oil filled HV apparatuses or use of composite insulators instead of porcelain insulators. Japanese patent JP3408893 B2 proposes a solution to the problem when a lightning arrester insulator is damaged. Upon a lightning strike, the internal pressure inside the insulation cylinder may rise abruptly. For this reason, the insulation tube ruptures, the insulation overcoat body is damaged, and there is a possibility that the lightning protection element or the like scatters to the surroundings. In the document, a cylinder of fiber bundle impregnated with resin is shown. The cylinder has two layers of which the outer layer has holes in it. The holes are machined and formed in the outer layer. When there is an internal pressure due to the insulator breaking, the inner layer will break at the holes of the outer layer to release the pressure. A problem with the solution is that the solution is part of the original product design and manufacture and cannot be used for retrofitting or post assembly. FR1370302A and US2016/0351305 describe related prior art. FR1370302A describes an electrical insulator assembly comprising a dielectric body adapted to pass through an opening in a wall of a closed chamber and to be fixed to this wall by a gastight junction, on this opening or around it; a substantially unbreakable shield also adapted to be fixed by a gastight junction on or around the opening and adapted to surround the part of the dielectric body which protrudes outside the wall, being arranged coaxially with a certain distance from this body, over the greater part of said body which projects; and a device adapted to establish a gastight junction between the shield and the projecting part of the body. US2016/0351305 describes a wildlife guard apparatus for an electrical insulator body including at least one guard assembly. Summary of the claimed invention It is an aim of the present invention to at least partly overcome the above problems, and to provide an improved shatter protection for a high voltage apparatus with a ceramic insulator. The present disclosure aims to provide a shatter protection for a high voltage apparatus with a ceramic insulator which can be used for retrofitting on existing equipment, is easy to manufacture, is easy to install and handle. These aims are achieved by the shatter protection as defined in claim 1 and the method defined in claim 9. Preferred embodiments/methods are claimed in the dependent claims 2-8 and 10-13. Summary of the disclosure According to an embodiment of the disclosure, it comprises a shatter protection for a high voltage apparatus with a ceramic insulator. The shatter protection comprises at least one electrically insulating tube, the electrically insulating tube comprising a plurality of holes going through an envelope surface of the electrically insulating tube. The electrically insulating tube has a diameter such that there is a minimum distance between the electrically insulating tube and the ceramic insulator when the shatter protection and the ceramic insulator are arranged concentrically. An electrically insulating tube with a specific diameter with holes going through the envelop surface is easily manufactured. The holes through the envelope surface will release the pressure from an explosion in the high voltage apparatus and the electrically insulating tube will catch fragments flying from the ceramic insulator. According to some aspects, the shatter protection comprises at least two electrically insulating tubes with different diameters and which are arranged concentrically with a distance between them. Two tubes with a distance between them will increase the safety of the shatter protection. If any pieces of the ceramic insulator pass the first electrically insulating tube, the second can catch them. There is also a free path for gas or liquid to flow through the two tubes to release pressure. According to some aspects, the holes of the at least two electrically insulating tubes are arranged such the shatter protection is closed seen from a centerline of the concentrically arranged electrically insulating tube