Transformer for fastening to a mast of an energy distribution network

Abstract

A transformer for mounting on a mast of an air-insulated energy distribution network has a core which is protected against corrosion and environmental influences, while at the same time stable retention is provided. The transformer contains a winding block having a solid insulating body, in which at least one upper voltage winding and at least one lower voltage winding are arranged. The winding block delimits a completely peripherally closed central retention opening. Furthermore, a core unit is provided which has at least one magnetizable core and is inductively coupled to each lower voltage winding by each upper voltage winding. The core unit extends through the retention opening via at least one core leg and annularly extends around the winding block on the outside by a ring portion. Retention devices are provided for fastening the ring portion to the mast.

Claims

1. A transformer for mounting on a mast of an air-insulated energy distribution network, having: a winding block having a solid insulating body, and at least one higher-voltage winding and at least one lower-voltage winding disposed in said solid insulating body, wherein said winding block delimiting an entirely peripherally closed central retention opening; a core unit having at least one magnetizable core being inductively coupled to said at least one lower-voltage winding by means of said at least one higher-voltage winding, wherein said at least one magnetizable core having at least one core limb and a ring portion, said core unit extending through said retention opening by means of said at least one core limb and annularly enclosing said winding block on an exterior by means of said ring portion; and a retainer for fastening said ring portion to the mast, said retainer including a supporting frame which entirely encloses said ring portion, said supporting frame containing a closed peripheral sidewall with a C-shaped cross-section, which entirely encloses said ring portion.

2. The transformer according to claim 1, wherein said core unit is impregnated with a curable polymer.

3. The transformer according to claim 1, further comprising an insulating material disposed between said supporting frame and said ring portion.

4. The transformer according to claim 1, wherein: said winding block has block limbs; and said core unit contains two cores each having a core limb, each of said cores extends with said core limb through said retention opening, and each of said cores encloses one of said block limbs of said winding body over its full periphery.

5. The transformer according to claim 4, further comprising at least one intermediate layer disposed between said core limbs of said cores which extend through said retention opening, said at least one intermediate layer delimiting cooling ducts.

6. The transformer according to claim 1, further comprising a plurality of intermediate layers disposed between said winding block and said core unit, said intermediate layers delimiting cooling ducts.

7. The transformer according to claim 1, wherein said retainer includes a fastening rail for fitting to the mast, and a hook connection.

8. The transformer according to claim 7, further comprising a base structure for a retention of said winding block, wherein said base structure is connected to said supporting frame.

9. The transformer according to claim 8, wherein said supporting frame and/or said base structure are equipped with a grounding nut.

Description

DETAILED DESCRIPTION OF THE INVENTION

(1) FIG. 1 shows an exemplary embodiment of the transformer 20 according to the invention in a schematic sectional side view. The transformer 20 incorporates a winding body 1, which comprises one or two solid and dry insulating bodies of cast resin, together with two lower-voltage windings and a higher-voltage winding. Said windings are not diagrammatically represented. The higher-voltage winding is arranged between the lower-voltage windings. The higher-voltage winding is further enclosed by a shielding which, likewise, is not diagrammatically represented.

(2) A bushing 3 is formed on the winding body 1, which extends from the winding body 1 to a free end, at which an overhead line terminal 30 is constituted. A further correspondingly configured bushing is arranged directly behind the bushing 3, in the viewing direction, and is thus not visible in FIG. 1. Moreover, the insulating ribs of the bushing 3 are schematically represented. An inner conductor, which is not diagrammatically represented, extends through the bushing 3, and connects the overhead line terminal 30 to the higher-voltage winding of the winding body 1. In the lower winding body section 23, low-voltage terminals 4 are configured, which are respectively connected to the two lower-voltage windings.

(3) The winding body 1 constitutes two winding body limbs 21 and 22, which are interconnected by means of a lower 23 and an upper 24 winding body section. The winding body limbs 21, 22 and the upper and lower winding body sections 23, 24 thus delimit a retention opening 25, through which a core unit 26 projects. The core unit 26 comprises a first core 2.1 and a second core 2.2, each of which encloses a winding body limb 21 or 22 over the full periphery thereof. Each core 2.1, 2.2 is a “wound core”, wherein each core is comprised of a plurality of winding strips or electrical steel strips, which are arranged adjacently to one another. The electrical steel strips or electrical steel sheets are comprised of grain-oriented electrical sheet steel, or of an amorphous material. However, wound cores of this type will be familiar to a person skilled in the art, such that it is not necessary to address the latter in any greater detail at this point.

(4) Each of the two cores 2.1 and 2.2 respectively comprises a limb, by means of which the respective core 2.1 or 2.2 extends through the retention opening 25. Externally to the retention opening 25, the core unit 26 extends around the winding body 1 in an annular manner at a ring portion 27.

(5) For corrosion protection, the cores 2.1, 2.2, and specifically both the ring portion 27 and the limb which extends through the retention opening 25 have been impregnated with a polymer, in this case a resin. The resin has been applied to the core in a liquid state in a vacuum kiln such that, on the grounds of the vacuum, the liquid resin penetrates all the interspaces of the respective core 2.1, 2.2. Thereafter, the resin is cured by the heat of the kiln, such that the electrical steel strips or the electrical steel sheets of the cores 2.1 and 2.2 are impregnated with resin. In this manner, effective corrosion protection is provided.

(6) For the enhancement of corrosion protection, but also for the fastening of the transformer 20, a supporting frame 5 is provided, which comprises C-shaped sidewalls which enclose the ring portion 27 of the core unit 26 over the full periphery thereof. In other words, the ring portion 27 is entirely arranged within the supporting frame 5. Between the supporting frame 5 and the ring portion 27, a corrosion-protection and an insulating material 6 is inserted, the function of which, firstly, is the provision of the requisite corrosion protection, and secondly the damping of noise associated with the operation of the transformer. As a corrosion-protection and insulating material 6, for example, an appropriate glass-fiber material is conceivable.

(7) On the supporting frame 5, a grounding nut 10, which is screwed onto a stud of the supporting frame 5 which is provided with an external thread, is discernible, wherein said stud is connected to the abovementioned shielding. The grounding nut 10 permits a simple grounding of the shielding, but also the connection of the transformer to a surge arrester, such that the desired overvoltage protection of the transformer is provided.

(8) Between the winding body limbs 21 and the respective section of the core 2.1 or 2.2, intermediate layers 9.1 are arranged, which are comprised of an elastomer and which constitute cooling ducts, which are delimited from the intermediate layer 9.1 to the respective limb 21 or 22, and to the respective core section. An intermediate layer 9.2 between the cores 2.1 and 2.2 also executes a delimiting function for the cooling ducts, wherein the intermediate layers are elastically configured and also assume a noise-reducing function.

(9) FIG. 2 illustrates the fastening of the transformer 20 according to FIG. 1 to a mast 8. To this end, the transformer 20 incorporates retaining means, which comprise a fastening rail 7.1 which is fastened to the mast 8 by means of two hook-shaped mast brackets 8.1. In each case, the fastening rail 7.1 constitutes a mating element 7.3 for the hook-shaped mast brackets 8.1, such that the fastening rail 7.1 can be rapidly and simply hooked into the mast bracket 8.1. The fastening rail 7.1 is rigidly connected to the supporting frame 5.

(10) In addition to the mast bracket 8.1, the fastening rail 7.1, the mating element 7.3 and the supporting frame 5, the retaining means comprise a base structure 7.2 which, in the exemplary embodiment represented in FIG. 2, is rigidly connected to the supporting frame 5 and supports the winding body 1 from below, such that an additional stabilization of the transformer 1 is ensured. In the exemplary embodiment represented, the fastening rail 7.1 and the base structure 7.2 are configured as separate components which are connected to one another in a detachable manner.

(11) For assembly, the winding body 1 is firstly produced, together with the bushing 3. Thereafter, the cores 2.1 and 2.2 are fitted around the winding body limbs 21 and 22, wherein the intermediate layers 9.1 and 9.2 are inserted. Thereafter, the supporting frame 5 is fitted, together with the corrosion-protection and insulating material 6. The fitting of the fastening rail 7.1 and the base structure 7.2 is then executed. The final stage is suspension in the mast bracket 8.1, which has previously been secured to the mast 8. In order to simplify assembly, for example with the aid of lifting vehicles such as cranes or similar, suspension openings 11 are provided in the retaining means M.

(12) FIG. 3 shows a further exemplary embodiment of the transformer 20 according to the invention. The mast bracket 8.1 shown here is equipped with an upper and a lower mast bracket 8.1, wherein each mast bracket 8.1 constitutes only a single hook, in which one mating element 7.3 can be suspended respectively. The mating elements 7.3 are again arranged on the fastening rail 7.1 which, on the side thereof which is averted from the mating element 7.3, is rigidly connected to a part of the supporting frame 5. The fastening rail 7.1, conversely to the exemplary embodiment represented in FIG. 2, is configured with an L-shape, and comprises a perpendicular section, which extends parallel to the mast, and a horizontal section, at which the fastening rail 7.1 engages with the winding body 1 from below. The fastening rail 7.1, at the side thereof which is averted from the mast 8, is also connected in this case to another part of the supporting frame 5, such that the winding body 1, the core unit 26 and the retaining means 5, 7.1 and 7.3 constitute a stable unit. The two said parts of the supporting frame 5 are screwed together. The part of the supporting frame 5 which is averted from the mast 8, in an overhead view of the transformer 20, is configured with a C-shape and, at the ends of its free limb, is screwed to that part of the supporting frame 5 which extends longitudinally in one direction.

(13) Lifting lugs 7.4 which are fastened to the supporting frame 5 simplify the installation of the transformer 20 on the mast 8 by means of a lifting crane.