EP2696358A1 - Medium frequency transformer - Google Patents

Abstract

The transformer has housings (200,201) inside which winding chambers (1-3) provided with primary and secondary windings (31,32) are arranged. The winding chambers are filled with an insulating fluid (87-91), and the housings are partially filled with insulating fluid so that the windings are surrounded by insulating fluid. The winding chambers are closed and separated from one another by using insulating partition wall (5,6). Isolation barriers made of solid insulation is formed within the housing for dividing the insulating fluid.

Description

Field of the invention

The invention relates to a medium-frequency transformer (MF transformer), for example, for converter transformations in the railway area, the usual catenary voltages of 15kV, 25 kV, 16 2/3 Hz and 25 kV 50 Hz, to DC voltages of 1.8 -3.6 kV. Of course, such an MF transformer is also suitable for other applications.

State of the art

It can be assumed that MF transformers in transformation converters with power electronics developed for this purpose are connected in series on the primary side and in parallel on the secondary side.

This MF transformer technology can significantly reduce the weight and volume of conventional transformers. In addition, it is possible to transform different voltages and frequencies when the MF transformer converter is designed for the higher of the different operating voltage.

Converter transformations opens the possibility to install drives in conventional trains and waggons, which are currently still covered with locomotives. This allows energy savings up to 40%.

On the other hand, it is also possible to install transformation converters in locomotives and high-speed trains, because with this transformation technology country or system boundaries of different voltages and frequencies can be traversed.

The framework data for this transformation technology are 15.25 to 25 kV rated voltage and 125-170 kV surge and 48-72 kV test AC voltage, respectively.

These rated and test voltages considerably exceed the usual voltage values for MF power transformers. Ie. As a rule, voltage values for rated or test voltages of 3-6 kV were rarely exceeded for MF transformers - if only with comparatively low powers. Power transformations above 80 kVA at 15-25 kV nominal voltage were unusual in this segment.

This means that the data of this type require MF transformers, new, not previously common technologies and construction methods.

In addition, there are high requirements for low leakage inductances, so that capacitor capacitances and weights of the required oscillation and resonant circuits are kept as low as possible.

This leads in the context of the present invention to previously unknown in this type MF transformers and concepts. In essential parts of these developments, counter-technical-physical requirements had to be brought to acceptable levels.

Furthermore, the electrical losses of these MF transformers were to be kept low, so that the overall efficiency of the actual converter transformation, consisting of a series of MF transformers with downstream converters, are higher than usual 16 2/3 Hz or 50 Hz transformers with quadrant controllers and converter configurations.

From the EP 1 344 230 B1 is a 15-25 kV and 8-11 kHz MF transformer known whose insulation between primary and secondary winding made of mica and Epoxydharzverguss is executed.

The disadvantage with not only this MF transformer is that solid insulation must be made very thin in order to achieve low leakage inductances between the primary and secondary windings. Furthermore, these types of insulation must not contain air pockets, which is difficult and can be achieved with great effort.

In the mentioned MF solid-state transformer, primary and secondary windings were made in rectangular hollow tubes with unequal expansion coefficients for insulation. Even if it is possible to produce layer-shaped insulating and / or cast materials void-free and acceptable in terms of partial discharge behavior (TE behavior), the question of the life of such transformers remains open.

In the case of solid insulation, there is always a risk of detachment of solid-rigid waveguides from intermediate or earth insulation after initial testing of the production. This can also happen for a long time after the transformer has been put into operation. For example, increasing TE values may lead to conductive carbon tunnel or "tree branching" channels between primary and secondary winding isolations.

At low rated voltages z. B. between 3-6 kV, the risk of tunneling or branching channel or TE heat transfer is relatively low, because the field strengths and TE intensities in cavities are usually not high and for a conductivity formation in the form of a conductivity tunneling in the Isolation usually insufficient.

For MF transformers with 15-25 kV rated voltage, the conditions are fundamentally different. In the insulation between primary / secondary windings prevail over conventional MF transformers significantly higher field strengths.

Even minimal cavities or detachments, which can also occur years after commissioning, are sufficient to cause inadmissible TE values, with the route tunneling progressing at these voltages.

In addition, in the case of a punch, high short-circuit power, with such incidents can reach the high short-circuit power from the overhead line in the drive area or the power electronics of the converter. This type of short-circuit transports can cause considerable damage. Primarily for these reasons, the permanent electrical safety of such MF power transformers is extremely important.

Waveguides made of aluminum or copper, as in EP 1344230B1 were preferably used, in comparison to MF strands with mostly high specific currents higher losses, which must be dissipated as heat, with appropriately sized coolers. When using conductors made of Cu or aluminum in MF transformers, the heat losses are usually with z. B. the flow of pure water through low-cross-section and long pipes derived, the additional disadvantage of this type transformers, the Stromverdrängungs-, and eddy current losses in the winding conductors. Even more important, however, is the isolation difference to conventional MF transformers.

Another MF transformer with a coaxial winding arrangement is in the EP 0874371A2 demonstrated. The disadvantages of an MF transformer with coaxial winding in planar design are system-related: relatively high power loss, possibly one-sided fluid cooling, difficult insulation between the coaxial conductors. Another publication of MF transformers was the article "Smaller, lighter, more efficient" in the ABB science journal ABB Technique 1/12 on pages 11 ff. These are obviously MF transformers designed according to the pattern of conventional Oltrafos, ie primary and secondary windings on intermediate insulation supports with oil gaps, in oil tanks, which receive the required number of MF transformers. This has several disadvantages. The need for a stable, relatively thick-walled and thus heavy oil container, which is lighter than conventional 1643 or 50Hz transformers, but still equipped with a large amount of oil, because these transformers are also outside the windings and cores filled with intermediate intervals with oil. Compared with the MF transformer assembly according to the invention in about 50 times more transformer oil / ester and in terms of volume required weight by a factor of 2-3 heavier and voluminous.

Description of the invention

Therefore, a primary object and object of the invention to provide a medium-frequency transformer, in which all the above-mentioned disadvantages of the known MF transformers are avoided. A very safe, durable and compact MF transformer with high transmission power was to be created, which is particularly suitable for 15-25 kV voltage and 16 2/3, or 50 Hz, also AC voltages, as part of the link with the transform converter volume and lighter weight and with the least use of fluid has a significantly lower fire load.

This object is achieved by a medium-frequency transformer having the features specified in claim 1.

Preferred embodiments of the invention and further advantageous features are specified in the subclaims.

The medium-frequency transformer described comprises a housing made of an insulating material, in which a plurality of windings are arranged, wherein the housing is at least partially filled with an insulating fluid medium.

The invention is characterized in that a plurality of winding chambers filled with the insulating medium are arranged in the housing, and in each case Winding chamber is arranged at least one winding, such that mainly only the windings are surrounded by the insulating medium fluid.

Preferably, the winding chambers are closed and separated by insulating partitions and "bottoms" and "lid". The windings are positioned and fixed in the winding chambers, the winding chambers being completely filled with the insulating fluid.

According to the invention closed winding chambers are provided, for example made of cast resin, wherein only after the manufacture of the housing parts, the windings, preferably MF strand windings 31-32 are used. The invention and the technical progress is seen in particular in that not the entire MF transformer, cores, etc. is filled with insulating fluid and surrounded, as has been customary in the prior art, but only the windings of the transformer of the insulating fluid Medium are surrounded. The winding chambers are designed such that the insulating fluid surrounds and surrounds only the windings. There is no further housing, e.g. made of metal, which constitutes a fluid container in which one or more MF-transformers are housed immersed in fluid.

The main advantage of the invention is that the required amount of insulating fluid can be drastically reduced in comparison to the hitherto known isolating fluid-filled transformers. The amount of insulating fluid required according to the invention is at most 1-2% of the amount needed in a conventional container-immersed MF transformer.
Due to the winding chambers filled and filled with the insulating fluid, the windings are at all times electrically insulated from the other parts of the transformer by means of two independent barriers to insulation, on the one hand the solid walls and, on the other hand, the insulating fluid.

The windings are used independently of the production of the winding chambers, so that any "trapped air" in the winding or forming gas inclusions are avoided. The winding chambers are then filled with an insulating fluid, such as Esther 87, transformer oil, 88, pure water 89 doped, refrigerant 90, or condenser insulating oil 91, or a gas. Any air bubbles in a liquid medium can be removed by means of a vacuum process and an air separator in the fluid circuit. However, with suitable pressures and adapted voltages, insulating gases such as sulfur hexafluoride, SF6 or even various refrigerants and increased air pressures would be possible.

Problems in the form of detachments, gaps and voids, as they occur in solid insulation, are excluded because the windings of insulating oil, ester or pure water are largely surrounded by air bubbles.

Of course, the requirements of conventional transformers z. As with 15.25 or 25 kV rated voltage according to IEC and VDE, at least be met.

The advantage of continuous line insulation around the windings is that the liquid insulations in the form of esters, oils, doped pure water or gas are suitable for effective insulation and heat dissipation from the MF strands, windings, also feedthroughs and connections.

From the above it can be seen that for transforming transformers with MF transformers in addition to the IEC voltage requirements new technological requirements could be formulated, because on the one hand low stray inductances between primary and secondary windings 31, 32 but also optional secondary windings - eg GU windings are possible. Insulation technology small distances between the primary and secondary windings on the one hand, and the lowest possible number of turns of the windings on the other hand provided. This leads, even on low Stray Inductors, to a new MF transformer category, as described here.

From the prior art z. B. MF transformers for 15.25 kV have become known in which the intermediate insulation between primary and secondary winding conventionally made of mica, cast resin or other insulation materials. This type of solid insulation provides a way to build MF transformers that operate between 15-25 kV. However, it is extremely difficult with conventional technologies to maintain constant low TE values, e.g. To realize threshold values smaller than, for example, 15 pC. One of the reasons are the rigid ladders in the transformer overfill, even though wheel-padding measures are performed. After curing of the resin significantly different expansions, also shrinkages between windings, layer insulation and potting after. And because these MF transformers are operated between -30 ° C to + 140 ° C, it comes to a lot of mechanical cycles during z. B. 30 to 50 years of operation.

As is known, intermediate isolations tend to be of z. B. Mica in the form of minimized distances between primary and secondary windings, with the inclusion of air or gas pores or columns to partial discharges (TE). This is because windings with and without stratified solid insulation without air pockets and pores are difficult to produce. Furthermore, there is always a risk of this winding insulation, because no "self-healing" properties such. B. immersed in capacitors in liquid insulation, are present. Even if conventional solid insulation could be made void-free and TE-acceptable, detachments from the rigid conductors may take place in later operation, with the result that increasing TE intensities will sooner or later lead to electrical breakdowns.
The first MF high power or traction transformers included Cu or Alu square tubes as windings, for B. pure water cooling. Despite sophisticated

Winding and buffering techniques must always be expected to involve conductor detachment and gap formation from and in the insulation.
In addition, there are significantly higher power losses, for example, greater than 3-4%, as in windings of MF or HF stranded conductors, which can be cooled from "outside" when appropriately closed and nested chambers are present as in the transformer described here.

The stranded coils enclosed by insulating fluid, as used in the invention, are substantially TE resistant because the insulating fluid is continually exchanged and / or cleaned and filtered. Because the windings are in closed solid chambers P 1-3, z. As lint or other contaminants in the liquid insulation does not accumulate between or the beginnings / ends of the windings - as in conventional oil transformers - and to deep-voltage flashovers between primary and secondary windings 32, 31 or against earth, z. B. the cores, P 45 lead.
In addition, stranded windings P92 are significantly less problematic in the production as pipe conductors, which are difficult to bend during the winding process and are otherwise difficult to handle.

Preferably, the primary / secondary windings 31, 32, 33 are nested to reduce the losses. The windings themselves are preferably made of MF strand or HF strand.

Today usual solid insulation, similar to the 50 Hz converter between 10-36KV, according to the invention is compared with a composite insulation system, in which the separation of the high voltage (HV) and low voltage (LV) areas and windings consists of solid and liquid insulation, which is a considerable Increasing the safety, voltage and performance of such transformers means. Differences between liquid insulation media such as Esther, transformer oil or pure water dopants exist essentially in different dielectric constants Transformer oil or Esther about 3-4, pure water, depending on the doping with 50-100, air with 1 and SF6 with about 3, as well as with breakdown voltages, viscosities and the ignition temperature, which is for example much higher in Esther than Trafoöl settled. In addition, there is no harmful biodegradability, with esther in the first place. Accordingly, Esther is the preferred intermediate isolation with insulating fluid because deionization cartridges etc. are not needed here. Alternatives are compressed air, SF6 and coolant gases, which are only suitable for special applications.

This also results in that z. B. Esther liquid insulations take significantly higher voltage components in rated operation and in the voltage test. Conversely, the voltage components to be absorbed for the solid insulation of a relevant transformer with the fluid pure water doped with glycol, are significantly higher.

According to the invention, as insulating fluid media, especially for lower voltages, also electro-negative gases, for example sulfur hexafluoride (SF6) with higher pressure, can also be used, e.g. Air or nitrogen are used, but, as mentioned, only for special applications in question.

The invention will be described in more detail with reference to the drawings. From the drawings and the description below, further features and advantages of the invention will become apparent.

Brief description of the drawings

Figur 1

Den Trafo und einen Schnitt durch die Wicklungen, Anschlusskästen und Kerne

Figur 2

Den Trafo und einen 90° gedrehten Schnitt durch die Wicklungen und Winkel-gedreht durch Wicklungsdurchführungen

Figuren 3

Das Trafogehäuse und die Wicklungskammern in Oval-Form und gleichen Umlauf-Querschnitten in verschiedenen Ansichten

Figuren 4

Den Trafo mit Wicklungskammern in verschiedenen Ansichten und Wellenform der Trenn- und Außenwände

Figur 5

Den Trafo und die Halterung der Wicklungen mit wellenförmigen Trennwänden

Figuren 6

Trapezegeformter Trafo, als Trafo- und Deckelgehäuse in verschiedenen Ansichten

Figur 7

Trafo-Gehäuse für vergrößerten Fenster- und Kernquerschnitt von Fig. 6

Figuren 8

MF- Trafo, Wicklungskammern, Wicklungen extern und hydraulische Verschaltung im Gehäuse

Figuren 9

Den Trafo, die Wicklungskammern mit Wicklungen und deren elektrische Verschaltung

Figuren 10A-10D

Mehrere MF-Trafos als Kaskadensäule aufgebaut

Figuren 10E-10J

Mehrere MF-Trafos, Gehäuse integriert, in einem Vielfach MF-Trafo Multifunktionsgehäuse

Figuren 11

Aufsetzen des Deckelgehäuses auf das Trafogehäuse zwecks Bildung eines Gesamt-Trafogehäuses mit geschlossenen Kammern.

Figuren 12

MF-Einzeltrafo komplett mit Spannrahmen ohne Anschlusskasten Verschlussdeckel.

Figur 13

Schnitt der Gerade-Seiten des MF-Trafos mit Abstands- und Luftkonfigurationsgestaltung zwischen Gehäuse und Kernen.

Figuren 14

Einzel MF-Trafo, vollständig mit Isolier-Dichtungsgesetzten Verschlussdeckeln der HV- und LV-Anschlusskästen.

Figuren 15

Spannmechanik der Kerne

Figur 16

Spannrahmen mit Mutter-Verschraubung oder Kühlkörpern

Show it:

FIG. 1

The transformer and a section through the windings, junction boxes and cores

FIG. 2

The transformer and a 90 ° turned section through the windings and angle-turned through winding bushings

Figures 3

The transformer housing and the winding chambers in oval shape and same circulation cross sections in different views

FIGS. 4

The transformer with winding chambers in different views and waveform of the separation and outer walls

FIG. 5

The transformer and the holder of the windings with wavy partitions

FIGS. 6

Trapeze-shaped transformer, as a transformer and cover housing in different views

FIG. 7

Transformer housing for enlarged window and core cross section of Fig. 6

FIGS. 8

MF transformer, winding chambers, external windings and hydraulic wiring in the housing

Figures 9

The transformer, the winding chambers with windings and their electrical wiring

Figures 10A-10D

Several MF transformers constructed as a cascade column

Figures 10E-10J

Several MF transformers, integrated housing, in a multiple MF transformer multifunction housing

Figures 11

Place the cover housing on the transformer housing to form a complete transformer housing with closed chambers.

Figures 12

MF single transformer complete with clamping frame without junction box.

FIG. 13

Section of the straight sides of the MF transformer with distance and air configuration between housing and cores.

Figures 14

Single MF transformer, complete with insulating gasketed HV and LV junction box covers.

FIGS. 15

Clamping mechanism of the cores

FIG. 16

Clamping frame with nut screw or heat sinks

Description of preferred embodiments of the invention

The Figures 1-16 show the basic structure of a MF transformer with, for example, solid ester or pure water insulation, in particular the separation chamber technique for primary and secondary windings 31, 32, the primary and secondary terminals, the hydraulic connections 59, 60, cores 45, core holding and connecting frame 50, 51 as well as the mechanical fixings in housings or cascades. The transformer and cover housing 200, 201 were realized in a closed chamber technology and other functional units such as hydraulic bridges and flow channels as voltage barriers between the primary and secondary windings 31, 32 installed. Carrier-sealed HV-LV terminal boxes and sealing covers 18, 25, with HV / LV insulation seals 19, 28 enable the first point-of-feeder-free MF transformers for various AC medium voltages and frequencies in DC inverters.

The MF transformer can be installed and used in high-voltage (HV) as well as low-voltage (LV) converter housings or transformer housings, such as floor, bulkhead or stack mounting, but can also be mounted on bulkheads with floor, ceiling or cascade mounting in LV rooms.

Connection techniques and designs of the transformer and cover housing are shown, up to multiple MF transformers in cascade installation according to Figures 10A-10D or in the form of a multifunctional housing according to FIGS. 10E, 10F ,

In the consistently high density of innovation of the invention, in addition to the far above average isolation security and cooling was also about that the losses in windings 31, 32, and cores 45 significantly smaller than conventional MF transformers and considerably smaller than conventional transformers of the frequencies 16 2/3 or 50 Hz.

This was achieved, inter alia, that the windings 31, 32, 33 are not made as previously hollow or solid conductors, but at the Place stranded MF or RF stranded coils 92 as anti-skinning and proximity conductors, the individual wires of which are e.g. B. are coated with insulating varnish.

So that the core losses are low, preferably nano-crystalline core material 45 is used, but this is not mandatory. The heat losses of nano-crystalline material are in part passed through the housing and elastic plate pads 49 into the interior of the transformer and can be removed there. Light air currents, which are required for other cooling, dissipate the surplus heat.

If, for reasons that are not performed, other core materials for 45 with higher losses, eg. B. amorphous material can be used, optionally a surface core cooling 53, Fig. 16 in the field of core separation cuts 50, 51 are incorporated. For this purpose, it is only necessary connecting rods 54 in the insulating core frame 50, 51 by the same configuration flat bars, designed as a cooler 53, exchange.

For further possible innovation boosts in future converter transformations can be further compressed MF transformers in multiple versions according to Figures 10 be realized that represent further, weight, volume reductions and assemblies and parts simplification.

FIG. 1 shows the transformer according to the invention in section. Preferably, the housing of the transformer is formed in two parts and consists of a transformer housing 200 and a firmly connected to this cover housing 201. The housing can also be a one-piece housing, if after the winding assembly transformer housing and cover housing are sealed. The transformer housing 200 comprises a plurality of winding chambers 1-3. These winding chambers 1-3 are separated from each other by insulating housing walls 4, 7 and insulating partitions 5, 6. If the transformer housing 200 is closed with the cover housing 201, resulting over insulating seals closed winding chambers 1-3, wherein in each winding chamber 1-3 either a primary winding 32 or a secondary winding 31, and optional secondary windings 33, are added. Via terminal boxes 11, 17, which are integrated on the transformer housing 200 and / or cover housing 201, the windings are connected via electrical feedthroughs 30 in the transformer housing 200 and cover housing 201 with electrical connections 36. The terminal boxes 11, 17 are sealed by covers 12, 18 and insulating seals 13, 19, ie, "voltage technology", closed. One or more cores 45 are arranged around the straight sides of the windings and their housings. The individual winding chambers 1-3 are completely filled with an insulating fluid 87-91, for example, ester or insulating gas. According to the invention, the strand windings 92 are introduced into the winding chambers 1-3, and the winding chambers filled with ester, transformer oil, doped pure water refrigerant or a suitable gas.

In the transformer according to the invention, the separate winding chambers 1-3 without windings, for example in the vacuum or Druckgelierverguss process prepared. The transformer and cover housing 200, 201 arising initially without winding and can be made without errors and without pores or gaps, especially in the area of the partitions 5, 6. Even if casting defects happen, they can be found by means of special TE measurements or X-ray procedures and the faulty housing parts can be eliminated.

The transformer housing 200 and the cover housing 201 are either materially bonded, for example, by an adhesive connection or potting, connected to each other, or they are non-positively and / or positively connected to each other by mechanical means. by externally attached to the housing clamping devices 25, 27, 46 connected to each other. In particular, for connecting the transformer housing 200 with the cover housing 201 and the covers of the junction boxes fastening means 74, preferably with spring elements 45th provided that connect the cover housing and the lid self-tightening with the transformer housing.

On the other hand, in conventional potting solid insulation techniques defects in intermediate insulation and boundary parts of the transformer windings, "oval-radial" arranged windings can not or hardly be located with current measurement and investigation methods. Unless about random hits, i. with object-destructive measures, errors are identified. It can be seen that such tests can only be used as a system test, but not as routine tests.

Another disadvantage of the production of the windings in solid-tube waveguide technology is that, in connection with usually high specific current intensities or MF frequencies, incomparably higher skin and proximity losses occur than in the cross-sectionally identical or cross-sectionally higher stranded HF or MF strands 92 used according to the invention.

Liquid insulation 87-91 combined with nonporous, thin solid partition walls 5 and 6 or more partitions and outer walls 4, 7, are advantageous because on the one hand the highest level of solid-insulation safety is achieved, and on the other hand, the heat loss of the windings 32, 31 can be easily derived via the circulating fluid insulation or circulating gas. The insulating and cooling medium, for. As oil, Esther, pure water or gas, z. For example, compressed air or SF6 or refrigerant gas does not have to be pumped through narrow cross-sections and long pipe lengths, but as an "outside-face coolant" is a continually-changing insulation even if there are air bubbles, eg due to non-manufacturing work are present externally in the liquid insulation and voltage is applied, there will be no defects, because the windings 31, 32 are in closed winding chambers Fig. 1 , 1-3 with insulating partitions 5, 6 are located. As a result of the circulation of the insulating fluid quickly changing air bubble constellations are generated in the transformer that no breakdown or flashover because the temporary TE intensities change constantly and extremely quickly, or disappear through the permanent air separation, as a result of which isolation damage could result.

The differences to solid insulation transformers, even to conventional oil or Esther transformers, are the plastic encapsulated primary and secondary windings 32, 31 with ester, pure water or gas 106, 107 Isolierstrecken between the primary and secondary windings 31, 32nd Die The individual winding chambers 1-3 comprise separately arranged on the housing 200 Fig. 1 , 60, or in the housing 200 integrated connection channels, FIG. 8 ,

Neither air bubbles nor moderately moisture-enriched esters or oils 87, or short or long lint or limited impurities in the liquid insulation can result in electrical breakdown between windings 32, 31 or 33. This is because medium-sized chamber walls 4-7 and hydraulic bridges as transitions Fig. 1 , 60 or Fig. 8 physically it does not allow it to come through or rollovers.

An evacuation process during the initial assembly of the transformer ensures that even cavities under the inner surfaces of the z. B. silk-covered strands 92 and their micro-cavities are filled with insulating fluid. This saturation of the cladding and wire spaces of the strands 92 in FIGS. 1-3 with the insulating fluid 87-91 is an important factor in achieving low TE intensities even at high voltages. The second major factor is that the stranded wires 92 are thermally conductively connected throughout the liquid insulation, which promotes the heat dissipation from the stranded profiles to the outside into the insulating fluid flow.
In particular, there are thermal differences compared to conventional transformers filled with oil or ester. Because not "slow internal" convection currents in the metal housing of the transformer determine the cooling effect, but actively pumped circulating currents at the windings 31,32, and pass through the bushings 9, 30, as well as the terminals 76, indirectly the Ringkontaktierungen 39 and Kontaktkraftgeschraubten contact resistors 112 and 39, the resulting heat loss is derived many times better than that with any other cooling method in filled with much conventional oil, but also often submerged MF transformers in smaller containers is possible. Due to the excellent cooling, the load currents of the primary and secondary windings can assume significantly higher values than specified by the nominal power, which is of decisive advantage, for example, for starting and braking operations, even for long uphill gradients.

In the MF transformer according to the invention Fig. 1-16 For example, the insulating fluid 87-91 or 106 and 107 filled in the winding chambers is forced into forced flow. Due to relatively small filling quantities, this leads to short circulation times and an effective and safe cooling on the outer surfaces of the windings 32, 31, the bushings 9, 30, 111, the terminals 76, and contacts 112, 39. This means that the dissipated heat loss of Trafos transported directly into a heat exchanger and can be passed through cooler into the atmosphere. Heat exchangers and coolers are external and not the subject of the invention. The cooling of the MF transformers by means of a fluid medium is usually realized only as a side connection to the cooling of the power electronics of the traction.

This effective forced cooling system by insulating fluid, eg. B. 87-91 or 106, 107 has compared to rigid-hollow winding conductors with pure water cooling the advantage that the MF transformer cooling system can be used without deionization for converter semiconductors, even other components with significantly different voltages, which is a considerable simplification for the overall system of a transformation converter.

Another advantage of the closed winding chambers 1-3 is the design of the housing and partitions 4-7, s. Figures 5 and 7 , The housing and partitions have integrated projections or separate Distance elements, by which the windings 31 are radially positioned and fixed in the winding chambers. For example, the housings and partitions may be wavy 95, 96 or trapezoidal 116, and physically separate the primary and secondary windings 32 and 31. Not only for normal operation, but also for strong shaking and impact stresses. or shorts, these are wave- or trapezoidal partitions 95, 96, 116, Fig. 5 and Fig. 5A between the winding chambers 1-3 a central element of the transformer. The "corrugations" or "trapezoids" of the partitions 95, 96, 116 are shaped so that the electric field strengths in the liquid and solid isolations are kept nearly the same, except immediately at the strand surfaces.

Between primary windings 32, secondary windings 31 and against earth 45, 46 there are two isolation barriers according to the invention, which "add together" and solid insulation in the form of housing and partitions 4-7 and liquid insulation 87-91, and partially external air gaps 16- 29 (FIG. Fig. 13 ). The liquid insulation is constantly kept in flow during operation and forms a constantly "regenerating fluid insulation" at the insulation-relevant points in and outside of the MF transformer.
The composite small and large impact lengths or creepage distances 16-29 and 42-55 in and on the terminal boxes 11, 17 and bushings 9, 30 belong to interrupted by isolating distances, creepage distance concept.

This inventive concept of insulation has decisive advantages: Electric flashovers or flashovers between primary 32 and secondary windings 31 can not actually take place. This applies, as already stated, even in the otherwise dreaded presence of fluff or fibers in insulating fluids or even along external configurations of the transformer, if no insulating and sealing barriers are present.

Because of the all-round enclosure of the windings with solid and liquid insulation in the winding chambers 1-3 for the primary and the secondary windings by means of partitions 5, 6, it is almost impossible to make a short-circuit or an approaching rollover between primary and secondary windings. and secondary winding 31, 32, 60 or against earth (cores 45, 46).

This is because the partitions 5, 6, the voltage difference between the primary and secondary windings 32, 31 shortened in time, could take over alone, but this does not take place due to the monitored fluid flows.

The spacings of the respective windings 32, 31 to the separating and outer walls 5, 6, 4, 7, between which liquid insulation 87-91 or gas insulation 106, 107 is filled, are on average about the same as the thickness of the insulating partitions. This results in a high level of combined safety and compliance with or below the specified TE thresholds

The securities add up in several respects, on the one hand due to the test-technically ensured pore or microporous freedom of the partitions and outer walls of the winding chambers, as well as the continuously exchanging liquid or gas insulation in all parts of the transformer, including axially and radially in the winding chambers 1-3 and the implementation areas 9, 30, ff. Unlike solid insulation, conductive channeling is virtually eliminated in all parts of the insulation.

As the Figures 5 and 7 show, the partition walls 5, 6 between primary and secondary winding chambers 1-3 offset mirror image mutually arranged wave contours 95, 96, the windings 92 (31-32) always "centered" between the partitions 95, 96 hold and fix. That is to say that sides of the winding opposite the wave crests always have a double liquid or gas insulation in addition to a solid insulation 87-91 and 106, 107, respectively.

In order not to lose this safety aspect in a two-part housing at the interface between transformer and cover housing, located on both sides of the end faces of the windings axial stops or spacers FIG. 2 , 98, 99, which are each axially "under" and "over" the windings arranged to the E-Feldstärken- between primary and secondary windings and the axially sealed ends of the winding chambers 1-3 to the windings 32, 31 also in the housing bonding areas Fig. 1 . 2 especially against the cores and tension bands 45, 46 to lower uncritical levels. In addition, in the outer region of the housing so-called recesses 42, 43 and Fig. 13 all-round air gap distances to the cores 45.

The FIGS. 1 and 8th show that joints between the housing walls 4, 7 and partitions 5, 6 of the transformer housing 200 and the cover housing 201 are provided with recessed into grooves 99 hydraulic-electric chamber seals 68-71. Thus, the axial distances 97 98 are reduced to the respective limitations on the groove bottom 99 of the transformer / cover housing with dimensioned passage / surface resistances in the range 97, 98, 99 field strengths that at shock or Prüfwechsel voltage, sufficient reserves are still available.

In addition, there are options for securing the dielectric strength in the joint area of the two housing parts 200, 201. Before complete assembly according to Fig. 12-14 of the transformer, the grooves 99 of the cover housing, if dispensed with the possibility of disassembly, are filled with metered-dose electrically high-strength adhesive resins, the groove base is placed in the subsequent assembly and curing dare to "down". This is from a transformer and a cover housing a self-contained provided with inner chambers one-piece transformer housing. This "fusion" of the transformer and cover housing can be carried out in several versions.

On the one hand, adhesively prepared grooves of the dividing wall joints of the cover housing 201 can be filled with adhesive resin before the gaskets are inserted into the grooves 99 so that transformer and cover housing 200, 201 are solid-insulated and mechanically become a single housing part. In this case, primary and secondary windings 32, 32 are mounted prior to joining with feedthroughs and seals, and the groove-adhesive fillings are dimensioned such that after the transformer housing has been placed in the cover housing, the adhesive resin 101 does not emerge from the grooves 99.

The groove surfaces and the uppermost Tennwandpartien be in the field of gluing the transformer and cover housing Fig. 8 . 9 so Klebe- treated that transformer and cover housing are materially connected, wherein the inner partitions 5, 6 and the housing inner and outer walls 4 and 7 by the adhesive bond 104 to be closed housing units.

The above operations could be performed with suitable adhesive resins without seals between transformer and cover housing 200, 201. Bonding in this respect would also transform the transformer and cover housing into a housing 101 without seals 68-71. So merge that could be dispensed with fastening means 73 between transformer and cover housing. There may also be other measures in the area of the joints, such as isolation insulation strips or wraparound caps with bushing (not shown), which significantly increase the electrical safety even without joint-gluing.

As a rule, however, can be dispensed with above-described bonding operations and dome constructions, because the seal compound 68-71 is sufficient for conventional nominal voltage levels.

In continuation of the above statements could on the connection shown transformer and cover housing 200, 201 with fittings 25, 27 and additional pressure build-up on transformer and cover housing by means of straps 46, via cores 45 and elastic-compressible plate pads 49 are dispensed with.

On the other hand, the use of straps 46 via cores 45 and the elastic plate pads 49 on the straight sides of the transformer and cover housing 200, 201, the screw 25, 27 according to Fig. 1 unnecessary. This has the advantage that the inventively proposed MF-transformers according to FIGS. 6 up to 20% becomes "narrower" because of the space for the screw connections Fig. 6B , 108 is omitted. Furthermore, the flange volume is reduced Fig. 7 , which opens up the possibility of the core cross-section Fig. 7 , 128 and to increase the voltage time surface or power of the transformer.

Such effective options for converter transformations also allow, e.g. B. up to 8-10 MF transformers stacked on top of each other or side by side, as in the Figures 10 is shown. Such an arrangement of several transformers leads to volume / weight reductions of the transformation converter, Figures 10 ,

An even more drastic reduction in volume is shown by the FIGS. 10E, 10F on. Proceeding to the FIGS. 10A to 10D is in this proposal, only the inner part of the recent transformer housing Fig. 1-9 used. The secondary single chambers 1-3 are in any multiple transformer collectives z. B. 3, 5 or 10 transformers to common, ie multiple secondary winding spaces, with the reduction potential of the omission of many outer walls 7 to a common outer wall 129 of the multiple MF transformer, but also internal interconnections under liquid and gas insulation, at least on LV-side.

Also in the execution according to FIGS. 10E, 10F The cores would be arranged per single or multi-integrated transformer in the atmosphere rather than in the oil or gas insulation. Transformer and cover housing would be made in example 3, 5, 10-fold execution.

The statements according to FIGS. 10A to 10F are another densification and weight reduction of converter transformation, which are a possible progression from single MF transformer to multiple MF arrangements.

Furthermore, the interior design of the winding chambers 1-3 and further embodiments of the MF transformer according to the invention will be described.

In FIG. 2 In particular, the electrical connections and feedthroughs to the windings and the seals between transformer housing 200 and cover housing are shown.
Thus, inter alia, in the bottom of the winding chambers 1-3, preferably cast-in-place spacers 98 for the windings 31, 32 are placed to the chamber bottoms so that the windings are analogous to the pitches of the winding spirals on the height-graded spacers Fig. 2 98, without obstructing the flow of the insulating fluid 87-91.
The counter-holder for the windings 31, 32 form the housing cover Fig. 1 with elastic spacers 110 or spacers 109 with which the windings 32, 31, 33 fixed with spring force, that is held vibration-resistant. Primary and secondary windings 32, 31 are provided with a series of spacers 109 and spacer sheets 110 at spaced distances from the lid housing 201 Fig. 1 . 2 held.

These axial fixations of the windings in the housing parts 200, 201 are required for axial movements of the windings 32, 31, 33 in the winding chambers during vibration or shock loads during train travel or magnetically induced short-circuit stresses Fig. 1-5 , 1-3 be stopped.

Although the beginning and end of the windings 31, 32 and their attachment to the bushings 9, 30 represent fixed supports of the windings, at certain intervals the windings 31, 32 can not be adequately supported in the winding chambers -13 in order to avoid damage caused by movement.

In the radial direction, the windings are held by the corresponding formed with wavy or trapezoidal projections partitions. alternative to Fig. 4 . 5 . 7 But there is also the possibility according to Fig. 8 the projections or spacers directly to the windings of primary, 32 and secondary winding 31 to arrange. In this case, the housing walls and partitions 4-7 are not wavy or trapezoidal but smooth Fig. 8A-E and form oval shapes around the cores 45. Nevertheless, a centering and fixing of the windings 31, 32 and uniform "insulating thicknesses" of the insulating fluid in the winding chambers 1-3 on all sides around the windings Fig. 8B are given, z. B. wave or trapezoidal shape having winding clips Fig. 8F, 129 and Fig. 8C , 130 are applied to the windings 32 or 31, the configuration of which would be configured to continue and unimpeded the liquid insulation 87-91 or gases 106, 107 the spaces between the windings 32 and 31 and the insides of the housing and partitions 4-7 fill up and exchange.

The illustrated advantageous features of the staggered shaft or trapezoidal shaped housing and partitions 95, 96 are also feasible here, when the secondary and primary windings Fig. 8 31, 32, 33 shaft tension elements Fig. 8F, 115 would be mounted offset, located in not equipped with waves chamber walls Fig. 8 , upper left representation support 1-7. This measure is an option for simpler transformer housing and cover according to Fig. 8 , and the Fig. 10 ,

In the axial regions of the winding chambers 1-3 and the windings 32, 31, 33, the thickness of the liquid insulation in the region of the passages 9, 30 reaches almost twice the values, as at the radial regions of the windings / winding chambers. This, so that in the area of field-deforming configurations, for example, the bushings larger proportions of the rated and the test voltages and their electric fields are shifted into the liquid insulation and degraded, or the stronger radii of the bushings 9, 30 in the field

Cone bores 64 and the radial spacings of the winding, separating or outer walls significantly lower TE field strengths obtained.

This measure of partial chamber widening Fig. 4 In the area of the winding heads is required so that input / output bushings of the primary and secondary windings are increasingly surrounded by liquid or gas insulation.
Also, allow the currents to have adequate diameter / cross sections Figure 4 , the feedthroughs 9, 30 and the conical bores 64 pass into and out of the windings of the winding chambers and there is no partial temperature increases with respect to feedthroughs in parts of the MF transformer.

In these enlarged chamber areas Fig. 4 . 1 . 2 are the bushings 9, 30 with soldering pockets, against rotation Fig. 1 . 2 , 113 arrested.
The seals around the bushings 9, 30 are in the cone bores Fig. 4 , 64 pressed and stretched in the insertion 64 radially deforming.

All forms, including options of closed winding chambers 1-3 for primary 32 and secondary windings 31 are designed so that the hydraulic-electric seals 68-71 also optionally described the adhesive addition measures, 99 -102, between transformer and cover housing are outside of the highest electric field strengths, which are directly on first and last turns of the primary / secondary windings 32, 31 and to the soldering pockets Fig. 2 . 8th , 38 attach the bushings.

There are Eingussarmatur screw 73 with clamping force adjustment 115 to compensate for setting operations of the seals 68-71 provided over 68-71 surface pressure on the housing and partitions 4-7 between transformer and cover housing Fig.1 . 2 , 200, 201 exercise. Thereby, the escape of ester or insulating media 87-91 or under higher pressure insulating gas 106, 107 from the closed housing 200, 201 is effectively excluded. At the same time, the housing and partitions 4-7 form the solid insulating barriers of the winding chambers 1-3.

The same applies to optional housing connection 99-102. The flow rates of the isolation hydraulics 88-91, alternatively the gas flow 106, 107, through the pathway for the liquid or gas isolation media 59-60-59 are 180 ° rotatable.

The insulating fluid 87-91 is supplied via an upper hydraulic port 59 and passed in parallel into the outer winding chambers 1 and 3. From there, the insulating fluid is conducted from the outer chambers 1,3 via a hydraulic bridge 60 to the inner winding chamber 2, from where the fluid is discharged through the chamber to the lower hydraulic port 59.
Of course, the flow direction of the insulating fluid can also be reversed 180 °. The supply of the insulating fluid to the hydraulic connections 59 can take place via external insulating hose connections. The hydraulic bridge could also be integrated in the housing of the transformer FIG. 9 , 103.

A bubble-free fluid-Umschluss the windings and all voltage-carrying parts with insulating fluid is thereby secured in the primary and secondary connections that grommets 9, 30, in the conical holes 64 for HV and LV connections in the transformer housing 200 and the cover housing 201 pressurized after vacuum pretreatment.

The insulating fluid 87-91 in the winding chambers 1-3 is preferably hydraulically maintained under pressure.

With contact screws 76 and the locking contact springs 77 for the primary and secondary ring contacts 39 at the terminals are low contact resistance between the windings 32, 32, the soldering pockets 38 of Bushings 9, 30 of the contact sleeve 112, the ring contacts 39 and the Anschlußkabein (without Pos,) produced.

The MF transformer isolation principle according to the invention: continuous series connection: solid partition walls 5, 6 and regenerating liquid insulation 68-71 or insulating gas 106, 107 is implemented without gaps, by all windings 32, 31, 33, with continuous chamber-shaped cavity solid insulation and liquid insulation Refills 68-71 were realized, which guarantee electrical and mechanical safety of the MF transformer. This also applies to the optional GU winding 33, the first and second layer Fig. 8 or 1.2 of the primary winding 32 is arranged and by means of intermediate insulation 34 surge voltage. In order to keep the stray inductance of the GU winding for the primary and secondary winding equally low, the GU winding 33 was realized as a surface winding 33-35. The GU winding 33 is preferably designed as a film winding 35 and is joined in a double insulation 34 enclosing on both sides. Pos. 35 shows that the GU winding between the 1st and 2nd layer of the primary winding 32 is placed. On the side, the film surface winding encloses Fig. 2 . 8th a stranded wire 35 so that a the leakage inductance lowering coverage between 1, 2 - given position to the primary and secondary winding winding.

Outside the transformer / cover housing primary and secondary terminals 30 field strength and TE minimizing ring contacts 39 in charge trapping terminal boxes in ua 11, 12, 17, 18, housed for the cable connections. This means that creepage distances and strike distances to potentials close to the planet, including cores 45 and tension bands Fig. 1 . 2 , dimensional but not in effect (type test) were minimized.
Because of significant room volume savings in the vicinity of the connection areas and hermetic encapsulation measures of the connections, in the form of molded terminal boxes, insulating gaskets, covers, and insulating sleeves 23 Fig. 1 . 2 . 13 , 119, vertical contact pressure 25 and horizontal pressure on 26, could Room distances are reduced analogously in medium-voltage systems to a fraction of otherwise usual distances and potential distances.

This is partly because the soft seal compression parts to cover 12 or spout z. B. 14 u.a. in conical compression holes in junction box 11 by mountable and removable MS insulation enclosures in the form of all-round charge carrier sealed closed junction boxes 11, 12, 17, 18, lids 12 have arisen.

In order to additionally generate voltage and reserve reserves in the area of the junction boxes, connections, 30, and related to> 25 kV transformers, it is optionally possible to separate the cores 45 with insulating caps and foils so that the cores do not act as continuous conductors but z. B. to a core number potential cascade between the HV, 11 and LV terminal boxes 17, are. This also applies to the GU connection 118 and the LV wiring box with 24, 28, 119, 27.

Conversely, however, there is also the option to short-circuit cores and straps 45, 46 and ground, thus placing a potential-separating grounding bridge between HV and LV junction boxes. Ie. to make the power MF transformer in addition to a potential separation between HV and LV converter part.

TE-triggering electrical field strengths are also avoided between terminal boxes and cores, for example, by insulating material recesses in the terminal boxes Fig. 4 , 42 in the HV and LV terminal box and under the elastic plates 49, Fig. 4 . 15 are provided, which additionally provide the cores on the HV and LV side at locations with increased E-field strength with air intermediate distances. These air gap inserts, to and between the cores that improve the field gradients, have been made to provide safe isolation configurations even outside the transformer.

With these measures, otherwise common pouring electrodes or area-Absteuerungsbeläge in and on the housings could be avoided.

In this sense, series circuits made of air-plastic-air barriers were consistently placed outside of the HV or LV junction boxes by these voltage-reducing barriers to the HV primary contacts 76, 39 via the positions 20, 21, 22 to the insides of the terminal boxes and over the HV-Luftschlagweitenabstand 22 are guided to the frame-hidden cores.

This outer space compression concept allows tightly packed MF transformer cascades, Figures 10 the entire surface, arc-base-free transformers. With room assignments also and especially in LV environments for which the grommets 23 designed mirror images and subsequent insulation and passage walls 133, 134 reflected in significantly MSverdichtet cascade configurations.

The great advantage of these feed-through versions, which integrate terminal boxes with, for example, a medium-voltage partition, is that the HV-LV-MF transformers do not have to be installed in the HV section of transformation converters, but can also be accommodated in LV rooms or cabinets are, s. Figures 10 , For this reason, the direct HV attachment to an insulation bulkhead Fig. 10C , 133, 134 possible because HV double insulation grommets Fig. 1 and 2 , 23 can operate with very short dimensioned high-voltage-resistant tube-taper clamping lengths.

The cores 45, 46 are held on the inside with transformer and cover housing and the elastically compressible plate pads 49 so that core weights and shaking forces on the elastic plate pads 49 of cover and transformer housing Fig. 1 . 2 . 12 . 13 clamp, axially with the core frame 50, 51, which also put on the inner sides of the intermediate plates 49 and act on the screwed frame parts 50 or 51.

The axial clamping device of the cores is in the Figures 15A-15C as well as the determination of the nuclei. In sprues on Trafo- and cover housing the cores 45 are tightened by screws, nuts 58 and tension springs 79, 80 by the frame members 50, 51 are axially compressed. So far, clamping bolts for clamping the cores were usually provided outside on transformer housings. These clamping bolts usually represented galvanic bridges between the low-voltage and high-voltage sides of the transformer. In the transformer according to the invention, sprues 73 are arranged on the housing with MS voltage levels. In the sprues fittings are fastened, which the clamping frames 50, 51, with which the cores 45 are tensioned and held 79, 80th

In Fig. 16 Furthermore, the connection of the frame parts 50, 51 with a metal rod part 53, 54 is shown, which, however, can also be exchangeable as a cooler with insulating liquid 87-91 or air, gas 106, 107.

Vertical sprues 130 face views Fig. 11 . 14 of the MF transformer alternatively allow the mounting in converter housings, mainly on lead-through walls Fig. 10 made of plastic or separate transformer screw connections on lead-through walls to transformer cascades. Fig. 10 ,

List of reference numbers

1

Secondary winding chamber, inside

2

Primary winding chamber, center

3

Secondary winding chamber, outside

4

Secondary housing wall, inside

5

Primary partition, center, interior

6

Primary partition, center, outside

7

Secondary housing wall, outer,

8th

Reinforcing ribs Transformer housing

9

Feedthroughs to the windings

10

Pipe fittings in the cover housing

11

HV connection box

12

HV cover on junction box

13

HV insulating gasket between junction box - cover

14

HV grommet for transformer junction box and optional bulkhead ducting

15

Kidney-shaped recesses in transformer and cover housing

16

HV-GU cable connection

17

LV junction box

18

LV cover on junction box

19

LV insulating gasket between junction box - cover

20

HV air clearance primary valve to HV inner wall

21

LV air clearance secondary to LV inner wall

22

HV to LV strike totaling 20, 21 via insulating gaskets

23

HV spouts cone for implementation in converter housing

24

LV junction box secondary connection winding

25

HV cover screw connection - pressure on seals

26

HV screw connection end-face pressure on Tüllenkegel

27

LV fitting Lid seal pressure

28

LV insulating gasket between junction box - cover

29

Material recess transformer / cover housing

30

Primary / sec. Feedthroughs, eg. B. casting resin in molded sleeves 37

31

Secondary winding, inside, outside

32

Primary winding with Gu winding

33

Gate, only Gu winding

34

Intermediate insulation GU to primary winding

35

Metal foil with wire between 1st and 2nd layer

36

GU connection to feedthrough fitting

37

Contact sleeve for receiving the bushings

38

Lötaschen on feedthrough fittings

39

Ring contact for primary, secondary and GU connections

40

Ring contact screw connection

41

Bonding of turns and windings

42

recesses

43

Insulation material cavity in the GU junction box

44

Heat conduction foil as intermediate insulation for cores

45

cores

46

Strap cores

47

Electrical connection cores via straps, optional version

48

free floating cores, standard version

49

Elastic plate support core to transformer and cover housing

50

Frame part 1 "Top"

51

Frame part 2 "Down"

52

Receptacles Frame for radiator or connection rod

53

Cooler for heat dissipation in the core section area

54

Connecting rod, for surface cooling of the cores

55

Frame rib, E stroke length extension

56

Pressure-receiving armature for core tension

57

Clamping plate - fitting

58

Clamping nut for actuator

59

Hydraulic connections, single, inlet, outlet

60

Hydraulic connections Hydraulic bridge Primary Secondary

61

Clamping flanges of hydraulic bridges

62

Cardan pulley between transformer / cover housing hydraulic bridge

63

O- seal hydraulic flanges and bridges

64

Cone bores for bushings in transformer housing and cover

65

Narrow Flange Cutout Transformer / Cover Housing

66

Narrow flange tension band imprint by means of cores

67

Friction sleeve cover housing

68

Chamber seal 1

69

Chamber seal 2

70

Chamber seal 3

71

Chamber seal 4

72

Seal for bushings in conical bore 64

73

Pouring fitting, main flange

74

Pouring fitting, junction boxes, covers

75

Pouring fitting, liquid insulation lock

73

Pouring fitting, for core adjusting bolts

74

Pouring fitting, clamping block

75

Clamping washers for tension main flange housing

76

Primary secondary gland contacts

77

Locking edge washer for ring contacts

78

Locking edge washer for connection cover

79

Tension spring for core tension

80

Tension spring for core clamping

85

Screw connection hydraulic connection

86

Screw connection hydraulic bridge

87

Liquid Isolation Esther

88

F. I. transformer oil

89

F. I. pure water with glycol

90

F. I. Refrigerants

91

Capacitor liquid isolation as substitution 87-90

92

Strand windings to implementation + preamble of 31,32

93

Secondary chamber wall, inside at Einschürung

94

Secondary chamber wall, outside at constriction

95

Waves in chamber walls

96

Strand support with shafts in chamber walls

97

Liquid isolation rooms

98

Axial distance winding

99

Groove bottom cover housing

100

Gießharzklebung

101

adhesive height

102

Increase the partitions if only adhesive connection of the housing ie seals omitted arise "one-piece Transformer housing" with well-closed chambers 1-3 (except one-outlet liquid insulation and sealed cone bores 64th

103

Oil channel primary secondary with housing integrated design

104

Adhesive connection transformer / cover housing without seals

105

Expansion chamber corners, groove base for chamber seals 68-71

106

Insulating gases SF6 and refrigerant gases as insulating and cooling gas

107

Compressed air as insulating and cooling gas

108

Width reduction measure - MF-Transformer

109

Rod rubber spacer in housing cover: secondary winding

110

Spacer sheet, housing cover, individual pressures: on primary winding

111

Seal: Bushing 37 Resin-encapsulated in housings

112

Current contacts Feedthroughs - Feedthrough sleeves

113

Bar-groove locks between feedthrough grommets

114

Clamping pressure adjustment of lid junction boxes

115

Waves Clamping element winding alternative to shafts 95, 96

116

Trapezoidal winding fixations in partitions

117

Contact sleeve current transfer surface Ring contact, cable

118

GU connections

119

Compression HV LV cover seals

120

Five chamber housing for z. For example, for primary sec

121

Inner wall I secondary winding against earth

122

Partition II LV Secondary to HV Primary

123

Partition III HV Primary to LV Secondary Exterior

124

Exterior wall IV LV Secondary exterior to earth

125

Multiple MF transformer in central housing outer wall to earth

126

attachment fitting

127

Core cross sections standard

128

Core cross-sections enlarged

129

Winding waves or trapeze winding clip

130

Winding connection plastic thin-walled part or binding

131

HV connection cable.

132

LV connection cable

133

HV bulkhead

134

HV bulkhead insulating gasket

200

transformer housing

201

cover housing

Claims (23)

Medium-frequency transformer consisting of a closed housing made of insulating material (200, 201) with winding chambers (1-3) for receiving primary and secondary windings.
characterized,
that in the housing (200, 201) a liquid of the gaseous insulating medium is introduced, which fills the winding chambers (1-3), existing through-openings to the winding chambers and feeds / drains for the insulating medium. Medium-frequency transformer according to claim 1, characterized in that the winding chambers (1-3) are closed and separated by insulating housing walls (4, 7) and partitions (5, 6) that the windings (31, 32) in the winding chambers are positioned and fixed, and that the winding chambers are filled with the liquid or gaseous insulating medium (87-91). Medium-frequency transformer according to one of claims 1 or 2, characterized in that the housing is formed at least two parts prior to assembly, a transformer housing (200), a cover housing (201) and junction boxes and mountable seals and covers. Medium-frequency transformer according to one of claims 1 to 3, characterized in that the windings are fixed axially and radially in the winding chambers (1-3). Medium-frequency transformer according to one of claims 1 to 4, characterized in that the housing walls and partitions (4-7) integrated projections (95, 96) or separate spacer elements (129, 130) through which the windings (31, 32) in the winding chambers (1-3) radially are positioned and fixed, wherein the windings are axially positioned and fixed by fixed (98.99) or elastic elements (108, 109) in the winding chambers (1-3). Medium-frequency transformer according to one of Claims 1 to 5, characterized in that the transformer housing (200) comprises the housing walls (4, 7) and the partitions (5, 6), and the cover housing (201) has grooves (99) into which the outer walls and partitions sealingly engage when closing the transformer housing. Medium-frequency transformer according to one of claims 1 to 6, characterized in that the transformer housing (200) and its housing walls and partitions with the cover housing (201) are glued or potted. Medium-frequency transformer according to one of claims 1 to 7, characterized in that for connecting the transformer housing (200) with the cover housing (201) and the covers of the junction boxes fastening means (74) with spring elements (45) are provided which cover the housing and the lid Self-tensioning connect to the transformer housing. Medium-frequency transformer according to one of claims 1 to 8, characterized in that in the housing, or the junction boxes (200, 201) fluid and solid insulated and electrically conductive bushings (30) are provided, with which the ends of the windings (31, 32, 33) on the one hand and the outer terminals for the windings on the other hand are electrically connected. Medium-frequency transformer according to one of claims 1 to 9, characterized in that the housing (200, 201) terminal cover (11, 17) are arranged, the compressed and gap-free insulating with the housing connect and insulated or sealed feedthroughs form the connections for the windings. Medium-frequency transformer according to one of claims 1 to 10, characterized in that the transformer cores (45) clamped on corner configurations and formations of the housing (200, 201) (Fig. 13) and separated by tension-elastic intermediate layers (49) from the housing and are held. Medium-frequency transformer according to one of claims 1 to 11, characterized in that the cores (45) by clamping bands and clamping frames (50, 51) are held radially and axially, and the cores with ribs (55) on the sides of the junction boxes on the outer sides Cover the core packages to parts and so increase the electrical surge voltage outside the cores. Medium-frequency transformer according to one of claims 1 to 12, characterized in that the cores (45) are grounded by electrical connection of the clamping bands (46), so that a galvanic potential separation between the external high-voltage and the low-voltage terminals of the transformer is given. Medium-frequency transformer according to one of Claims 1 to 13, characterized in that material recesses (39) are provided on the formations of the housing (200, 201) for fastening the cores (45). Medium-frequency transformer according to one of claims 1 to 14, characterized in that axially arranged intermediate insulation (130) between the cores (45) are arranged. Medium-frequency transformer according to one of claims 1 to 15, characterized in that the clamping frames (50, 51) for receiving the cores (45) are designed so that at least partial cooling of the cores (131) by means of insulating fluid or by heat sink can be integrated. Medium-frequency transformer according to one of claims 1 to 16, characterized in that a primary winding (32) is provided with two or more layers, wherein between the layers of the primary winding, an auxiliary winding (33) with intermediate insulation (34) is included. Medium-frequency transformer according to one of claims 1 to 17, characterized in that the individual winding chambers (1-3) have at least one inlet and an outlet (59) for the insulating fluid, which are preferably arranged diagonally opposite to the housing, wherein the insulating fluid predominantly uniformly through the winding chambers (1-3) is promoted. Medium-frequency transformer according to one of claims 1 to 18, characterized in that the inlet (59) of a winding chamber by a hydraulic bridge connection (60, 103) with a drain (59) of another winding chamber is connected, wherein the hydraulic bridge either in the housing integrated (103) or designed as a separate component (60) and connected to the housing. Medium-frequency transformer according to one of claims 1 to 19, characterized in that the inlets and outlets (59) in the housing consist of angled channels, which preferably attach axially to the housing (200, 201) and enter radially into the winding chambers (1-3). Medium-frequency transformer according to one of claims 1 to 20, characterized in that the inlets and outlets (59) for the insulating fluid comprise hydraulic or pneumatic couplings, in particular self-sealing quick-release couplings of electrically insulating material. Medium-frequency transformer according to one of claims 1 to 21, characterized in that the housing (200,201) of the transformer on the top and bottom uniformly dimensioned fittings, so that a plurality of such transformers isolated in all layers are connectable and directly stackable. Medium frequency transformers according to one of claims 1 to 22, characterized in that several of these transformers are summarized in cascades or partial cascades, and these are combined so that they form a common housing (120) with a common configuration in multiple units (125) ,

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