Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
88643
BACKGROUND OF THE INVENTION
This invention relates to gas-insulated high-voltage, high power
transmission lines and more specifically relates to a novel flange ring
construction for securing an outer periphery of a support insulator to the gas-
filled enclosure of the system.
High voltage gas-insulated transmission lines are well known in the
art and generally consist of a central conductor which is carried within a gas-
filled enclosure by a support insulator, which may have a disc or conical con-
figuration. The support insulator will have a central opening which receives the
central conductor with fixed or sliding engagement, and the outer periphery of
the insulator is fixed to the outer enclosure.
Typical prior art arrangements for supporting the central conductor
within its grounded housing are shown in U.S. Patent 3,813,475, entitled
"Grounded Gas-Insulated Bus Enclosure-Combined Enclosure Joint Backup Ring and
Contamination Control Device" and in U.S. Patent 3,886,301, entitled Plug-In
Joint For High Current Conductors in Gas-Insulated Transmission Systems, both in
the n:me of John C. Cronin.
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~88643
In the above arrangements, the housings are relatively
large in diameter, for example, 20", and the encl~sure material,
which may be of aluminum, having a thickness of about 1/4",
is relatively flexible. Though the connection of the rigid
insulation support to the interior of the enclosure is complex
and has required effective support structures.
BRIE~ DESCRIPTION OF THE PRESENT INVENTION
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The principle o~ the present invention is to provide
a novel isulator support structure, whereby the insulator outer
periphery is clamped between the opposing ends of two housing
sections. Two relatively heavy weld rings are welded to the
respective ends of the two housing sections and these two
rings have internal diameter clamping shouIders which clamp
against the outer periphery of the insulator, thereby to
hold it in position. The rings also engage one another in
surface-to-surface engagement and are secured to one another
by a welding bead, which extends around the outer periphery
of the rings. Preferably, a compressible seal ring is placed
between the rings and against the outer periphery of the
insulator to form a gas-tight seal, and to prevent contami-
nation products created during the welding from entering the
interior of the enclosure, which is to be kept as clean as
possible.
; Preferably, the welding rings may be arranged to
have a short overlapping relationship at their external
periphery in the manner of a bell and spigot joint to center
the rings relative to one another during assembly.
The use of the relatively large cross-sectional area
welding rings is useful in making the enclosure more rigid at
its ends to insure alignment with an adjacent enclosure section
than it would be if it were entirely self-supporting.
88643
BRIEF DESCRIPTION OF TH~ DRAWINGS
.. . .
~ Figure 1 is a cross-sectional view along the
- length of a gas-insulated bus in which the supporting in-
sulator is supported in accordance with the present inven-
tion.
Pigure 2 is a cross-sectional view of Figure 1
taken across the section line 2-2 of Figure 1.
Figure 3 shows a second embodiment of the inven-
tion wherein the support insulator also serves as a gas
barrier and wherein the support insulator is slidably connected
to the central conductor.
,:
Figure 4 is a cross-sectional view of one of the
welding rings used in Figures 1 and 3.
- Figure 5 is a cross-sectional view of the other
of the welding rings shown in Figures 1 and 3.
; Figure 6 is a cross-sectional view of a welding
~, ring similar to that of Figure 5 wherein the welding ring is
; provided with an annular seal-receiving groove in one of its
faces.
DETAILED DESCRIPTION OF THE DRAWINGS
Referring first to Figures 1 and 2, there is
` disclosed a section of a gas-insulated transmission line
which is adapted for carrying electrical power in a high-
voltage transmission system and wherein the line can be rated
at 345,000 volts. Note that the invention is also applicable
in gas-insulated substation application. The transmission
line generally comprises a central high-voltage conductor
10 which is supported within the interior of an enclosure 11
by a conical insulator support 12. In the transmission line,
a plurality of spaced insulator supports, identical in con-
struction to insulator 12, may be used. The conical insulator
12 in Figures 1 and 2 could be replaced by other insulator
shapes, such as disc-shaped insulators or the like.
1~88643
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The insulator 12 in Figures 1 and 2 is of the
sliding type in that insulator 12 slidably engages the outer
diameter of conductor 12. Thus, disc 12 has a conductive
aluminum insert 13 molded therein, which receives spaced
rings 14 and 15 which may be made of polytetrafluoroethylene.
Rings 14 and 15 secure the internal diameter of insulator
12 to the conductor 10 and enable easy sliding of the
insulator 12 relative to conductor 10, due to dimensional
changes in the transmission line due to temperature change
and the like. A flat conductive spring member 16 is provided
between rings 14 and 15 to make electrical connection be-
tween conductive insert 13 and conductor 10.
The insulator 12 is also shown in Figures 1 and 2
as having gas passages 20 to 27 to enable the circulation
of gas past the insulator 12. Th~s, the interior of conductive
~! housing 11, which may be of aluminum, is filled with a suit- -
able electronegative gas, such as sulfur hexafluoride, at a
pressure of about 60 p.s.i.g.
In accordance with the present invention, a novel
Z0 support structure is provided for fixing the insulator 12
within the housing 11. Thus, in accordance with the inven-
tion, the housing 11 is separated into two halves 30 and 31.
Relatively massive large cross-sectional area welding rings
32-33 are then welded to the ends of housing sections 30 and
31, as shown in Figure 1. Welding ring 32 is shown, before
welding, in Figure 4, and welding ring 33 is shown before
welding, in Figure 5. As shown in Figure 1, welding ring
32 is welded to enclosure 30 by the weld beads 40 and 41, while
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the welding ring 33 is welded to enclosure section 31 by ~he
weld beads 42 and 43.
The welding rings 32 and 33 are so constructed that
they define two internal shoulder regions 44 and 45 respectively,
for clamping on the sides of upwardly extending peripheral
ridge 46 of the insulator 12. The shoulder 44 is defined, in
part, by the chamfer 47 in ring 33 which exposes only the
lower portion of the side of ring 32.
Rings 32 and 33 are further constructed so that they
define a short bell and spigot arrangement for positioning the
rings relative to one another, when they are brought together
and clamped against the outer periphery of insulator 12. Thus,
in Figures 1, 4 and 5, ring 32 has a reduced diameter shoulder
50 and ring 33 has a projecting ledge 51, which overlaps
shoulder 50,thereby to automatically centrally locate the
rings relative to one another when they are brought together.
The two rings and thus the enclosure sections are
joined together, and clamp insulator 12 in place, by a
single weld bead 55 extending around the outer junction
between rings 32 and 33. Preferably, a compressible O-ring
seal 56 is captured beneath chamfer 47 and is pressed against
outer periphery 46 of insulator 12 and against shoulder 44
of ring 32, in order to provide a seal against entry of
welding flux or contaminants created during the formation of
weld bead 55.
Figure 3 shows a second embodiment of the invention
wherein all of the numerals given in Figures 1 and 2 identify
similar components in Figure 3. In the arrangement of Figure
3, an additional seal 60 is provided between shoulder 45 of
ring 33 and the extending periphery 46 of insulator 12.
1~86~3
Moreover,in the ~rrangement of Figure 3, the insulator is
shown as a complete gas barrier without openings and,
further, the insu}ator is fixed to the conductor 10. Thus,
in Figure 3, the interior diameter of aluminum insert 70
is fixed to conductor 10 as by an epoxy cement 71. Preferably,
the epoxy cement 71 is a conductive cement, and may have an
aluminum or conductive particle filler or the like, to insure
good electrical connection between conductor 10 and insert
70.
A still further embodiment of the invention is
shown in Figure 6, which shows a ring 80, which can replace
rIng 33 in the embodiments of Figures 1 and 3. Thus, the
ring 80 of Figure 6 is not provided with the chamfer 47 of
ring 33, but rather has an annular notch 81 in the surface
which faces ring 32.
The notch 81 is then adapted to receive a sealing
0-ring 83, which will be pressed against the opposing surface
of ring 32 in Figures 1 and 3, when the rings are brought
together and are welded to one another.
In the foregoing this invention has been described
in connection only with illustrative embodiments thereof.
Since many variations and modifications of this invention will
now be obvious to those skilled in the art,it is preferred
that the scope of this disclosure be limited not by the
specific illustrative embodiments herein set forth but only
by the appended claims.
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