Abstract
Dry-type transformers with insulating modules are disclosed. Example insulating modules include dielectric screens and supporting blocks. The supporting blocks support the dielectric screens over windings of the transformer. The dielectric screens have first substantially even portions configured to adapt in spaces defined by corresponding cylindrical barriers arranged between first and second windings of the transformers and second substantially even portions, transversal to the first portions and to the first windings of the transformers and extending outwards from the first portions and beyond the supporting blocks. The dielectric screens partly extend around a winding.
Claims
1. A dry-type transformer, comprising: at least a first winding; at least a second winding; one or more cylindrical barriers between the at least first and second windings; one or more insulating modules, each insulating module comprising: a dielectric screen and a supporting block, the supporting block to support the dielectric screen over the first winding of the transformer, the dielectric screen partly extending around the second winding and having a first substantially even portion configured to adapt to a space defined by a corresponding one of the one or more cylindrical barriers arranged between the first and a second windings of the transformer and a second substantially even portion, transversal to the first portion and to the first winding of the transformer and extending outwards from the first portion and beyond the supporting block.
2. The dry-type transformer, according to claim 1, the second portion comprising an aperture to receive a connecting part of the supporting block.
3. The dry-type transformer according to claim 1, the one or more cylindrical barriers comprising multiple cylindrical barriers, each insulating module comprising: a plurality of dielectric screens, each dielectric screen configured to be arranged with a different cylindrical barrier, respectively, of the transformer.
4. The dry-type transformer according to claim 1, comprising one or more flexible dielectric screens, bent at a rim between the first portion and the second portion.
5. The dry-type transformer according to claim 1, the first portion having a curvature to match a curvature of the corresponding cylindrical barrier.
6. The dry-type transformer according to claim 1, comprising a single piece, the dielectric screen being made of a first dielectric material and the supporting block being made of a second dielectric material.
7. The dry-type transformer according to claim 1, the dielectric screen or the supporting block or both being made of resin.
8. The dry-type transformer according to claim 1, each dielectric screen comprising one or more insulation layers.
9. The dry-type transformer according to claim 1, further comprising one or more horizontal sheds extending radially outwards from the supporting block.
10. The dry-type transformer according to claim 1, at least the first or the second part of the dielectric screen partly extending around the second winding along the corresponding cylindrical barrier.
11. The dry-type transformer according to claim 1, the supporting block being stacked one on top of another supporting block with the second portions interleaved between interlocked supporting blocks.
12. The dry-type transformer according to claim 1, the first winding being an LV winding and the second winding being an HV winding.
13. The dry-type transformer according to claim 12, at least one block extending above the one or more cylindrical barriers and comprising a portion resting on one or more LV windings of the transformer.
14. The dry-type transformer according to claim 1, the one or more insulating modules further comprising one or more respective collars.
15. The dry-type transformer according to claim 14, the one or more respective collars resting on top of a dielectric screen or screens.
16. A dry-type transformer according to claim 1, comprising multiple windings, sets of insulating modules being arranged between consecutive windings.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) Non-limiting examples of the present disclosure will be described in the following, with reference to the appended drawings, in which:
(2) FIG. 1 is a schematic partial view of a prior transformer having angle rings;
(3) FIG. 2A is a perspective view of an insulating module according to an example.
(4) FIG. 2B is a sectional view of an insulating module according to an example.
(5) FIG. 2C is a perspective view of a multi-screen insulating module according to an example.
(6) FIG. 3 is a schematic partial view of a transformer including insulating modules according to an example.
(7) FIG. 4 is a schematic sectional view of a transformer including insulating modules according to an example.
(8) FIG. 5A is a section view of an insulating module cast in one piece, according to an example.
(9) FIG. 5B is a perspective view of a transformer portion with an insulating module, according to an example.
(10) FIG. 6 is a section view of a transformer with an insulating module cast in one piece, according to an example.
DETAILED DESCRIPTION OF EXAMPLES
(11) FIG. 2 is a schematic view of an insulating module according to an example. Insulating module 200 may include a screen 205 and a supporting block 210. The screen may include a first portion 215 and a second portion 220. The second portion 220 may extend from a rim of the first portion 215 and may be substantially flat and perpendicular to the first portion 215. The first portion 215 may include one or more layers of dielectric material and may have a size (thickness) configured to fit in a space defined by one or more cylindrical barriers of a transformer. Such space may be the space between a winding and a cylindrical barrier or the space between two consecutive cylindrical barriers.
(12) The second portion 220 may include an aperture. The aperture may be designed to host at least part of the supporting block 210. In the example of FIGS. 2A and 2B, the aperture may be circular and the supporting block 210 may have a top portion with an aperture or recession R substantially corresponding to the aperture of the second portion 220 of the screen. As shown in FIG. 2B the recession R may be sized to match a corresponding protrusion P of another supporting block 212.
(13) The example of FIG. 2A and FIG. 2B is merely one example of how the second portion and the supporting block may interconnect. In other examples, the top portion of the supporting block may include the protrusion and another supporting block may include a recession at a bottom part to receive the protrusion. In yet other examples, the second portion and the supporting block may be cast in one piece. In yet other examples, more than one screen and more than one supporting block may be cast in one piece. Thus, there may be no need for apertures and/or interlocking pieces. One skilled in this field may appreciate that other configurations may also be possible.
(14) FIG. 2C is a perspective view of a multi-screen insulating module according to an example. The insulating module 250 may include a supporting block column 255 in the form of a single piece of dielectric material (e.g. epoxy resin) with dielectric screens 260. The lower part of the supporting block column 255 may be configured to be resting on a winding, e.g. HV winding, of a transformer. Each screen may have one or more holes to allow the epoxy to flow during the casting of the supporting block column 255, so all elements form a single piece. Each screen may have a first portion 260A substantially parallel to the supporting block column 255 and a second portion 260B traversing the supporting block column 255. Said traversing may be perpendicular to the axis of the supporting block column. The first portions may be configured or shaped, e.g. the may be curved, to adapt to a space between cylindrical barriers of the transformer. Starting from the lower dielectric screen and moving upwards, the second portions 260B may progressively get longer as the respective dielectric screens may correspond to cylindrical barriers that are further away from the supporting block column 255. The second portions may also include a central hole to allow for the hole-pin interface of the supporting blocks to engage as shown in FIGS. 2A and 2B.
(15) FIG. 3 is a schematic partial view of a transformer having insulating modules according to an example. Transformer 300 may be a dry-type transformer. The transformer 300 may include an HV winding 305 and an LV winding 310. A series of cylindrical barriers 315 may be interposed between the HV winding 305 and the LV winding 310. On top of the HV winding an insulation module 320 may be placed. The insulation module 320 may include supporting blocks 325 and flexible L-shape screens 330 stacked one on top of the other. Each supporting block 325 may support a screen 330. Each screen 330 may be arranged with a cylindrical barrier. Starting from the bottom and going upwards, the first screen 330 may be arranged with the first cylindrical barrier between the HV winding and the LV winding. The first (bottom) supporting block 325 may thus support the first (lowermost) screen 330. Accordingly, the second supporting block 325 may support the second screen and so on. The second portion of the second screen may partially extend over the first cylindrical barrier so that the first portion of the screen may be arranged with the second cylindrical barrier. Accordingly, the second portion of the third screen may partially extend over the first and the second cylindrical barrier so that the first portion of the third screen may be arranged with the third cylindrical barrier. As the distance between the HV winding and the barriers increases when arranging screens with cylindrical barriers in a direction approaching the LV winding 310, the second portion may be longer in the radial direction of the transformer. To maximize structural support, supporting blocks may be placed on top of the uppermost screen and may extend beyond the innermost cylindrical barrier and include a second pillar that may be supported on the LV winding. The L-shape screens may be placed almost parallel to the equipotential lines to maximize insulation properties. To accomplish this, the bending radius at the rim between the first portion and the second portion may increase as the distance from the HV winding increases.
(16) FIG. 4 is a schematic sectional view of a transformer having insulating modules according to an example. In the example of FIG. 4, six cylindrical barriers are arranged between HV winding 405 and LV winding 410. An insulating module 420 may be arranged between the HV winding 405 and the LV winding 410. The insulating module 420 may include a set of supporting blocks 425 interrupted by inverse L-shape screens 430. In the example of FIG. 4, three screens 430 are arranged with the three cylindrical barriers, respectively. Each screen 430 is supported by a respective supporting block 425. On top of the uppermost screen 430, a supporting block may be placed extending above and beyond the innermost cylindrical barrier and extending vertically to be supported on the LV winding, thus the insulating module 420 may be π (pi) shaped having a leg in the form of an inverse pyramid.
(17) Each supporting block may include a single element, as is shown in FIG. 4, or may include one element for the LV winding and another for the HV winding without any mechanical connection between them. The latter is preferable to supporting blocks made of epoxy because their casting is then simpler. Furthermore, some supporting blocks may include horizontal sheds extending outwards from the main supporting block structure. It is also possible to incorporate the insulating modules with angular rings or collars. In FIG. 4, sheds 435 are interposed between supporting blocks thus maximizing the insulation properties of the transformer.
(18) FIG. 5A is a section view of an insulating module cast in one piece, according to an example. The insulating module 500 may include a supporting block column 510, integrated dielectric screens 520 and collars 525. The supporting block column and dielectric screens may be cast in one piece and may be made, for example, by epoxy resin. Thus various protrusions may extend outwards from the supporting blocks to increase creepage. Collars 525 may be resting on top of the screens 520. In other examples the dielectric screens may also be cast using the same mold and also be made of resin.
(19) FIG. 5B is a perspective view of a transformer portion with an insulating module, according to an example. Transformer 550 may include insulating module 555, winding 560, cylindrical barriers 565 and collars 570. Insulating module 555 may include supporting blocks 557 and dielectric screens 559. The dielectric screens 559 may have a first portion parallel to the supporting block column and may be arranged to fit in a space between the cylindrical barriers 565. A second portion may be transversal, preferably perpendicular, to the first portion and may traverse the supporting block column. The collars 570 may rest on top of the second portion of dielectric screens 559.
(20) FIG. 6 is a section view of a transformer with an insulating module cast in one piece, according to an example. Transformer 600 may include a first winding 605 and a second winding 650. On top of the first winding 605 an insulating module 610 may rest. More specifically, the insulating module 610 may include a supporting block column 615 and dielectric screens 620. Cylindrical barriers may be arranged between the first winding 605 and the second barrier 650. First portions of the dielectric screens may be arranged in spaces between the cylindrical barriers, extend beyond the cylindrical barriers and be connected at a rim with second portions, transversal, preferably perpendicular, to the first portions. The second portions may traverse the supporting block column and extend beyond the supporting block column. Collars 625 may be resting on top of second portions of dielectric screens 620.
(21) Although only a number of examples have been disclosed herein, other alternatives, modifications, uses and/or equivalents thereof are possible. Furthermore, all possible combinations of the described examples are also covered. Thus, the scope of the present disclosure should not be limited by particular examples, but should be determined only by a fair reading of the claims that follow. If reference signs related to drawings are placed in parentheses in a claim, they are solely for attempting to increase the intelligibility of the claim, and shall not be construed as limiting the scope of the claim.
