EP0154697B1 - High-voltage winding with constrained potential distribution for transformers - Google Patents

Description

The invention relates to a high-voltage winding with controlled voltage distribution for transformers with large nominal powers, special conductors which are currentless in normal operation being wound up to form capacitor coils for voltage control.

When exciting windings with oscillating switching voltages at a frequency that corresponds to a natural frequency of the winding, i.e. with resonance excitation, the resulting amplitudes and gradients of the resonance-frequency voltage distribution are higher, the lower the effective winding damping. These high amplitudes and large gradients are very undesirable.

To control the voltage distribution in high-voltage windings of transformers, a capacitor battery has become known from DE-A-23 28 375, the individual capacitors of which winding sections assigned to them are connected in parallel. These capacitor banks are arranged spatially next to the transformer windings and are therefore not linked to the flux passing through the high-voltage windings. These capacitor batteries therefore ensure a good distribution of impulse voltages impinging on the transformer winding, but on the other hand cause only minimal or no damping of vibrations in the windings excited by switching voltages.

Transformer windings provided with control conductors behave similarly in accordance with DE-B-10 69 279, DE-A-24 18 230 and DE-A-23 23 304. These known winding arrangements also consist of disc coils with wrapped control conductors or of winding layers wrapped control conductors built windings. The control conductors provided in the known windings are capacitively coupled to the associated winding and are de-energized in normal operation. These control conductors also have only a very slight influence on the damping of vibrations in the windings excited by switching voltages.

From DE-A-21 17 422 an adjustable power transformer is known, with a cylinder winding that can be connected to a high-voltage network and consists of a main and step winding, and a series circuit comprising an ohmic resistor and a capacitor for damping winding vibrations when subjected to surge voltage Serving and connected in parallel to a winding part RC element, in which the step winding connected to a switching device consists of a coarse step winding that can be switched on and off and a fine step winding that is provided with tapping and coaxially arranged, the coarse step winding between the radially outer fine step winding and the radially inner one Main winding arranged and the RC element are connected in parallel to the coarse step winding and the effective resistance of the RC element for an angular frequency corresponding to a natural vibration of the coarse step winding is approximately equal to its reactance is selected.

This serves to improve the damping of the electrical vibrations both in the part of the control winding of this transformer which corresponds to the coarse step winding and in the part corresponding to the fine step winding.

The invention is therefore based on the object of providing an arrangement for high-voltage windings with controlled voltage distribution of the type mentioned at the outset, by means of which a good effective damping of oscillating voltages in the windings is ensured in the region of their natural frequencies.

This object is achieved in high-voltage windings with capacitor coils connected in parallel in that the capacitor coils are chained with the same flux as the high-voltage winding to be controlled and in that the two sides of each capacitor formed by the capacitor coils are connected to one another via an ohmic resistor, so that they are connected to one another together represent an RC element inductively coupled to the high-voltage winding.

According to advantageous refinements and expedient further developments, each capacitor coil is designed as a double-disc coil consisting of two or four spatially wound conductors, one side of the capacitor coils is connected to the high-voltage winding via a potential connection, and the ohmic resistors and / or the capacitor coils are in shield rings provided for controlling the end potential field , foil-wrapped, non-conductive material.

Another advantageous embodiment consists in that the currentless conductor is also wrapped in the high-voltage winding and connected to it via an ohmic resistor, so that the conductor of the high-voltage coil is itself one side of the capacitor.

Expedient embodiments of the invention when used in fine-stage layer windings consist in the fact that the currentless conductor represents an additional gear in a fine-stage layer winding designed as a multi-start spiral, or in a fine-stage layer winding that is interwoven in sections with two stages per section for an odd number of stages one in one section existing idle gear is connected to the ohmic resistor and serves as a currentless conductor.

Appropriate configurations of the ohmic resistor used also consist in the fact that it is voltage-dependent or that it consists of the parallel connection of a voltage-dependent resistor with a fixed resistor.

Expedient embodiments of the invention when used in normal, not interwoven, coils consist in the fact that the currentless conductor is installed as an additional coil between two coils of the winding or in that the currentless conductor or capacitor coating is designed as a shield ring.

The analog solution for normal, not interwoven, layer windings is to design the currentless conductor or capacitor covering as an input sign.

The wiring of high-voltage windings according to the invention is very advantageous because it enables frequency-dependent damping of voltage oscillations in the high-voltage winding in a simple manner by suitably setting the ohmic resistance, without causing a significant increase in losses at the operating frequency. A particularly effective damping of the high-voltage winding is forced by arranging the capacitor coils in the region of the antinodes of the magnetic stray field.

Embodiments of the invention are explained in more detail with reference to a drawing.

• Figur 1 eine Wicklung beliebiger Art mit je einer Kondensatorspule in der axialen Wicklungsmitte und an einem axialen Wicklungsende,
• Figur 2 eine Kondensatorspule aus zwei räumlich parallelen Leitern in einer Scheibenspulenanordnung,
• Figur 3 eine Kondensatorspule aus vier räumlich parallelen Leitern in einer Scheibenspulenanordnung,
• Figur 4 eine Kondensatorspule, deren eine Kondensatorseite von dem den Laststrom führenden Leiter einer Scheibenspulenwicklung dargestellt ist,
• Figur 5 eine Grobstufenlagenwicklung,
• Figuren 6 und 7 je eine
  Feinstufenlagenwicklung,
• Figur 8 eine in eine normale Doppelspulenwicklung eingebaute stromlose Zusatzspule,
• Figuren 9 und 10 Kondensatorspulen, deren stromloser Belag als Schirmring ausgebildet ist, und
• Figur 11 eine Kondensatorspule, die aus der Eigangslage und dem Eingangsschild einer Lagenwicklung besteht.

In all figures, only the basic conductor arrangements are shown in section. In detail show:

• 1 shows a winding of any type, each with a capacitor coil in the axial winding center and at an axial winding end,
• FIG. 2 shows a capacitor coil made of two spatially parallel conductors in a disk coil arrangement,
• FIG. 3 shows a capacitor coil made up of four spatially parallel conductors in a disk coil arrangement,
• FIG. 4 shows a capacitor coil, one capacitor side of which is shown by the conductor of a disk coil winding carrying the load current,
• FIG. 5 a coarse layer winding,
• Figures 6 and 7 each
  Fine layer winding,
• 8 shows a currentless additional coil installed in a normal double coil winding, FIG.
• Figures 9 and 10 capacitor coils, the de-energized coating is designed as a shield ring, and
• Figure 11 shows a capacitor coil, which consists of the initial position and the input plate of a layer winding.

Corresponding parts are provided with the same reference symbols in all figures.

According to FIG. 1, a winding composed of two parts 12 and 13 lying axially one behind the other is arranged around an iron core leg 11, which is only indicated by a dashed line. The winding is carried out in a known manner as a layer or disc coil winding. Between the two parts 12 and 13 and below the part 13 on the end face, a capacitor coil 14 is arranged, each consisting of two currentless conductors 15. The currentless conductors 15, each forming a capacitor coil 14, are wound spirally to form a disk coil, which, due to their spatial arrangement, are chained in front of or between the end faces of the parts 12 and 13 with the same flux as the winding itself.

The connections of the two sides of the capacitor formed by a capacitor coil 14 are connected to an ohmic resistor 16. As a result, each of the capacitor coils 14 forms an RC element together with the resistor 16 assigned to it. The capacitor coils 14 and the winding of the parts 12 and 13 are inductively coupled to one another as a result of the linkage with the same flux, so that the resulting damping resistance of the RC element is transferred into the winding by means of a transformer. This damping keeps the amplitudes of vibrations excited, for example, by switching voltages, in manageable orders of magnitude without any particular effort.

In the embodiment according to FIG. 2, the capacitor coil 14 consists of two disk coils, which have the same dimensions as the disk coils in the adjacent parts 12 and 13 of the connected winding. In this embodiment too, the capacitor coil 14 is spirally wound from two currentless conductors 15. The two conductors 15 are crossed out in the area of the inner windings of the disc coils. The two sides of the capacitor are connected to one another via a voltage-dependent resistor 17. The capacitor coils 14 and the parts 12 and 13 are in turn inductively coupled to one another, so that a damping resistor is also transmitted into the winding in this arrangement.

The arrangement according to FIG. 3 largely corresponds to that according to FIG. 2. However, in this case the capacitor coils 14 are spirally wound from four currentless conductors 15. In addition, a parallel circuit comprising a fixed resistor 16 and a voltage-dependent resistor 17 is provided as an ohmic resistor.

The embodiment according to FIG. 4 also relates again on a winding of disc coils, the winding being composed of parts 12 and 13. In this embodiment, however, the conductor of the winding carrying the load current, which is also wound in the region of the capacitor coils 14, additionally takes on the function of a currentless conductor, so that only a single currentless conductor 15 is required. This currentless conductor 15 is guided over two disc coils and also crossed out in addition to the outcrossing of the conductor carrying the load current. Opposite the cross-over, one end of the conductor 15 and the winding of the conductor carrying the load current, the other end of which is adjacent, are connected to one another by a fixed resistor 16. As a result, in addition to the inductive coupling of the winding to the capacitor coil 14, its potential is determined. By appropriate dimensioning of the currentless conductor 15, the capacitor coils 14 also preferably have the dimensions of the disk coils in the parts 12 and 13 of the winding.

FIG. 5 shows a single-layer coarse stage winding with a conductor 18 carrying the load current and a currentless conductor 15 wound in parallel with it spatially. The two conductors 18 and 15 in turn form the two sides of a capacitor. One end of the coarse stage winding is connected to the other end of the currentless conductor 15 opposite its other end via a fixed resistor 16, so that an RC element which is inductively coupled to the coarse stage winding is formed.

FIG. 6 shows a fine-stage winding consisting of four conductors 18 with the taps 1 to 5 that are spatially parallel in one position and carry the load current. An electroless conductor 15 is also wound into this winding position in an additional gear. The beginning of one of the conductors 18 carrying the load current is connected to the end of the de-energized conductor 15 via a fixed resistor 16 analogous to the embodiment according to FIG. 5.

Finally, FIG. 7 shows a single-layer fine-stage winding, interwoven in sections, with taps 1 to 10 and with two stages per section, so that an even number of gears is required. Considering the level selector, however, an odd number of levels is appropriate. As a result, there is an idling gear with the number of turns of one stage in such windings. In the exemplary embodiment shown in FIG. 7, the end of this idling gear is connected to the beginning of the associated step winding via a fixed resistor 16. As a result, in this arrangement, the idling gear takes over the function of the currentless conductor 15 by forming a coil-shaped capacitor with the turns of the associated step winding, which in turn, with the fixed resistor 16, represents an RC element which is inductively coupled to the fine step winding.

FIGS. 9-11 show a high-voltage winding, the capacitor coil 14 and / or the resistors 16, 17 being inserted into shielding vings made of film-wrapped, non-conductive material for controlling the end potential field.

Claims (10)

1. A high-voltage winding with controlled voltage distribution for transformers of a large nominal output, having specific conductors (15) which are currentless during normal operation wound to form capacitor coils (14) for the voltage control, characterised in

- that the capacitor coils (14) are influenced by the same flux as the high voltage winding (12, 13) to be controlled; and

- that the two sides of each capacitor formed by the capacitor coils (14) are connected to one another by means of a resistor (16, 17), so that together with said resistor they represent an RC- element which is inductively coupled to the high voltage winding (12, 13).

2. A high-voltage winding as claimed in Claim 1, characterised in that each capacitor coil (14) is designed as a double disc coil consisting of two or four conductors (15) wound to be spatially parallel (Figures 2 and 3).

3. A high-voltage winding as claimed in Claims 1 and 2, characterised in that one side of the resistor (16, 17) is connected to the high-voltage winding by means of a potential connection.

4. A high-voltage winding as claimed in Claims 1 to 3, characterised in that the capacitor coils (14) and/or the resistors (16, 17) are inserted into screening rings provided for the front potential field control and consisting of non-conductive material, around which foil is wound (figures 9-11

5. A high-voltage winding as claimed in Claim 1, characterised in that the currentless conductor (15) is interwound into the high-voltage winding and connected thereto by means of the resistor (16, 17), so that the conductor of the high-voltage coil is itself one side of the capacitor (Figures 4, 5, 6 and 7).

6. A high-voltage winding as claimed in Claims 1 and 5, characterised in that the currentless conductor (15) represents an additional strand in a closely-stepped layer winding which is designed as a multi-thread spiral (Figure 6).

7. A high-voltage winding as claimed in Claims 1 and 5, characterised in that a closely-stepped layer winding is respectiively interwound as an uneven number of stages with two stages per section, and an idling thread present in a section is equipped with the resistor (16, 17) and serves as a currentless conductor (Figure 7).

8. A high-voltage winding as claimed in one of Claims 1 to 7, characterised in that the resistor (17) is voltage-dependent.

9. A high-voltage winding as claimed in one of Claims 1 to 7, characterised in that the resistor consists of the parallel connection of a voltage-dependent resistor (17) and a fixed resistor (16).

10. A high-voltage winding as claimed in Claims 1, 5 and 8, characterised in that the currentless conductor (15) is a coil installed into a conventional double coil winding (Figure 8).

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