EP3427275B1 - Replacement transformer having a modular structure - Google Patents

Description

The invention relates to an arrangement for replacing a multi-phase transformer with several single-phase transformers, each of which has a housing filled with an insulating liquid, in which a core with a high-voltage and a low-voltage winding is arranged, at least one high-voltage bushing and a releasably connectable to the housing and with Have a cooling module filled with insulating liquid for cooling the insulating liquid, wherein both the housing and the cooling module each have at least one cooling liquid inlet and at least one cooling liquid outlet, which can be connected to one another for the exchange of insulating liquid.

Such an arrangement is from the US 3,235,823 A already known. A three-phase power transformer is described there, which has a lower tank section for each phase. The three lower tank sections are connected to each other via an upper tank section, with the upper tank section being divided into three parts. In this way, the lower tank sections and the three parts of the upper tank section can be transported independently of one another and connected to one another on site. The connection is made by welding. The previously known arrangement also has cooling units which are firmly connected to the transformer tank via upper and lower bolt brackets. Each cooling unit is connected to the internal volume of the tank or housing via an upper inlet and a lower outlet, so that the insulating fluid with which the tank is filled can be circulated via the respective cooling unit. The brackets are bolt-shaped and serve to securely and permanently connect the cooling unit and tank.

The DE 10 2007 022 641 A1 describes a transformer that has a predetermined transport profile for simplified transport does not exceed. The transformer has a housing in which sockets are arranged, into which a high-voltage bushing can be inserted when the transformer is assembled on site.

From the DE 19 71 624 U A hermetic transformer is disclosed which has membrane-like cooling elements.

The GB 271 168 A discloses a transformer tank which is detachably connected to a cooling unit. In order to prevent the escape of cooling liquid when the cooling unit is removed, the tank is equipped with a check valve which is automatically moved into its closed position when the cooling unit is removed from the tank.

In electrical supply networks carrying alternating voltage, transformers are used to convert high voltage into low voltage or vice versa. Large power transformers in particular are often the size of an apartment building. The transformers are designed according to the respective customer requirements, so that they are usually manufactured as tailor-made, one-off products. In the event of a fault, such transformers are a critical component for the security of the network supply, as the failure of the transformer interrupts the energy supply. In order to be able to replace the faulty transformer, a replacement transformer must be carefully designed and manufactured according to the requirements. This can lead to delays of up to over a year. Additionally, due to its heavy weight and size, transporting the replacement transformer is time-consuming and can take several weeks depending on weather conditions. Further delays occur on site due to the long commissioning times.

The object of the invention is therefore to provide an arrangement with which faulty transformers can be quickly replaced can be. A commissioning time of between 48 and 72 hours should preferably be possible.

The object is achieved by an arrangement for replacing a multiphase transformer according to claim 1 and a method for replacing a multiphase transformer according to claim 5.

The arrangement comprises at least one feedthrough socket, which is connected to the high-voltage or low-voltage winding via a winding connection line extending within the housing, the high-voltage feedthrough being insertable into the feedthrough socket, and an intermediate piece for the fluid-tight connection of the coolant outlet and the coolant inlet, each coolant outlet and each Coolant inlet is equipped with a fluid-tight closing valve and wherein the intermediate piece delimits a connecting channel and has a vent opening for venting the connecting channel.

According to the invention, an arrangement is provided with which a multi-phase transformer can be replaced quickly and easily, so that a rapid resumption of the power supply is possible. The arrangement according to the invention can be transported quickly and assembled on site within a few days. If the arrangement according to the invention is in operation, the faulty multi-phase transformer can be replaced with a new transformer without any problems. If the faulty multi-phase transformer has then been replaced with a new multi-phase transformer after, for example, three years, the arrangement according to the invention can be dismantled and is available for new uses.

In order to be able to transport the transformer to the faulty one as quickly as possible, a modular design was chosen within the scope of the invention. Instead of a multi-phase and thus heavy replacement transformer, several single-phase and thus lighter transformers are provided. the number of single-phase transformers the number of phases of the faulty transformer. In other words, for example, a three-phase transformer is replaced by three single-phase transformers. The single-phase transformers themselves are also modular in design. The first module is the housing filled with insulating liquid in which the core with high-voltage and low-voltage windings is arranged as the active part. The structure of the core and the high-voltage and low-voltage windings is basically arbitrary within the scope of the invention.

The housing is also equipped with feedthrough sockets which are connected to a winding connection cable on the side facing the insulating liquid. The winding connection cable is in turn connected to one of the windings. If it is the high-voltage side feedthrough socket, for example, the winding connection cable is connected to the high-voltage winding. However, if it is a feedthrough socket on the low-voltage side, for example, it is connected to the low-voltage winding via the winding connection cable.

A pluggable high-voltage bushing is provided as a further module according to the invention. The high-voltage bushing comprises an insulator extending in a longitudinal direction, through which a high-voltage conductor extends. The high-voltage bushing has a fastening connection from which a plug-in section extends to its free transformer-side end, which is designed to be complementary in shape to the bushing socket. During assembly, the plug-in section is inserted into the bushing socket. The high-voltage bushing is then fixed to the housing by means of a fastening connection. In the inserted position, the high-voltage conductor of the bushing rests on a line bolt that is held insulated at the closed end of the bushing socket. The line bolt contacts the Winding connection cable and extends through the otherwise non-conductive inner wall of the feed-through socket. The feed-through sockets have sealing agents and thus seal the interior of the housing fluid-tight.

The column section expediently extends vertically or at right angles to a horizontal housing cover of the housing, so that the weight of the high-voltage bushing is introduced directly from above, i.e. vertically, into the bushing socket. The weight of the bushing thus ensures a high contact force within the socket, so that good insulation is provided by a solid body connection. The high-voltage bushing is advantageously connected to the bushing socket by means of a suitable detachable connection, for example a screw connection.

Finally, according to the invention, a cooling module is provided which can be transported independently of the remaining components of the respective single-phase transformer, which can be detachably connected to the housing and which can be filled or filled with insulating fluid on site before assembly. After connecting the cooling module to the interior or oil space of the housing, the insulating liquid is passed over the cooling module and thus cooled in the desired manner.

Due to the modular structure, within the scope of the invention, instead of a central, very heavy and very difficult to transport unit, several lighter modules or components are provided, which can be easily transported inexpensively and quickly to any location. The pluggable design of the high-voltage bushing and the bushing sockets also enables quick assembly on site.

According to the invention, both the housing and the cooling module each have at least one coolant inlet and at least one coolant outlet, which are used for exchange of insulating liquids can be connected to one another, each coolant outlet and each coolant inlet being equipped with a fluid-tight closing valve. Because both the cooling module and the housing are each equipped with a closing valve, these modules can be or will be filled with an insulating liquid, for example a common insulating oil, before they are installed. During assembly, each coolant outlet of the housing is connected to a coolant inlet of the cooling module and each coolant outlet of the cooling module is of course connected to an assigned coolant inlet of the housing. In this way, the insulating liquid heated by the active part of the housing, i.e. the core and the high and low voltage windings, can be passed over the cooling module and thus cooled.

The cooling module can basically have any design. For example, the cooling module can be a passive cooling module that has cooling fins in which the insulating liquid is circulated. On the outside of the cooling fins, the cooling module is in heat-conducting contact with the outside atmosphere, so that heat is transferred from the insulating liquid to the outside atmosphere.

Within the scope of the invention, an intermediate piece is provided for the fluid-tight connection of the coolant outlet and coolant inlet, wherein the intermediate piece delimits a connecting channel and has a vent opening for venting the connecting channel. In this embodiment of the invention, the insulating liquid that exits from a coolant outlet is guided to a coolant inlet via the connecting channel of the intermediate piece. The intermediate piece further simplifies the assembly of the cooling module on the housing. The intermediate piece can be rigid or have a flexible, movable section. The connecting channel, which is tubular for example, extends from an inlet opening of the intermediate piece to its outlet opening. During assembly, the intermediate piece is connected fluid-tight with one side to a coolant inlet and with the other side to a coolant outlet. To prevent air and/or moisture from getting into the insulating liquid, the connecting channel of the intermediate piece can be vented. This is done via the vent opening and, for example, by creating a vacuum in the connecting channel using a vacuum pump. After the vacuum has been created in the connecting channel, the closing valves of the coolant inlet and the coolant outlet can each be opened. In one variant, the intermediate piece has a drain opening that can be closed fluid-tight, which allows insulating liquid to be drained from the connecting channel before assembly.

In one embodiment, each single-phase transformer of the arrangement according to the invention has an expansion vessel which can be connected to the housing via a connection for exchanging insulating fluid, the expansion vessel being arranged on a separate holding frame. In other words, the expansion vessel is mechanically held by its separate holding frame. Like the cooling module, the expansion vessel is also connected to the inside of the housing or, in other words, to the oil chamber, so that insulating fluid can reach the expansion vessel via the said connection and vice versa. The volume of the insulating liquid depends on the temperature. If the temperature increases, the volume of the insulating fluid increases. Due to the constant internal volume of the housing, an additional volume in the form of the expansion vessel is required to accommodate the additional volume of insulating fluid that arises at higher temperatures. The expansion vessel can be equipped with a dehumidifier or a gas compression chamber or the like. The exact design of the expansion vessel within the scope of the invention is arbitrary. What is important, however, is the separate arrangement and mounting on the holding frame. This ensures simple and accelerated assembly.

According to an expedient further development in this regard, the holding frame is set up to hold the expansion vessel above the cooling module which is releasably attached to the housing. The holding frame has, for example, a bottom facing a foundation or floor and an upper top facing away from this, which is directly connected to the expansion tank. For example, metallic struts extend between these two sides and are connected to one another in such a way that the necessary free space is provided to accommodate the cooling module, which is also attached to the housing or to the holding frame.

Conveniently, the holding frame is part of the cooling module, whereby the cooling module is connected to the housing via the holding frame.

Further advantages arise if the cooling module has a holding frame which is equipped with a lifting handle for lifting the holding frame and a hook part for hooking into a counterpart attached to the housing. The lifting handle is, for example, a ring-shaped, closed lifting eyelet which has an inner diameter which enables a conventional crane hook to be hooked in and thus the holding frame and thus the entire cooling module to be easily lifted. In contrast to this, the lifting handle is also designed to be hook-shaped. The hook part and the counterpart, for example a simple bolt, form a hook connection which enables the cooling module to be hooked onto the housing and thus enables the cooling module to be quickly installed. The counterpart is, for example, a bolt which extends parallel to a housing wall, for example the cover, and which is held at a distance from the said housing wall.

Advantageously, at least three feedthrough sockets are provided. The bushings are advantageously airtight and liquid-tight on the housing attached. They each enable the associated high-voltage bushing to be quickly plugged in and thus quick assembly on site. By providing at least three bushings, the arrangement can be operated with multiple input voltages and can therefore be used more flexibly. The feedthrough sockets are designed to be complementary in shape to the insertion section of the respective high-voltage feedthrough. The high-voltage feedthrough is dimensioned depending on its operating voltage.

The invention also relates to a method for replacing a multi-phase transformer using an arrangement described above. In the method, a number of single-phase transformer housings corresponding to the number of phases of the multi-phase transformer are placed in the vicinity of the multi-phase transformer. The transformer housings are releasably connected to a cooling module, the high-voltage bushings are mounted in bushings of the transformer housing, and the high-voltage bushings are connected at their connections to a supply network and a load.

As already explained in connection with the arrangement according to the invention, the transport and assembly time is significantly shortened both by the modular structure and by the selection of a few modular single-phase transformers, so that the supply of public or private consumers can be quickly resumed after a failure of a multi-phase transformer can.

Figuren 1, 2

einen einphasigen Transformator eines Ausführungsbeispiels der erfindungsgemäßen Anordnung in perspektivischer Ansicht zeigen,

Figur 3

einen fehlerhaften mehrphasigen Transformator während des Betriebs schematisch verdeutlicht,

Figur 4

die erfindungsgemäße Anordnung als Ersatz des fehlerhaften mehrphasigen Transformators nach Figur 3 zeigt,

Figur 5

das Gehäuse eines einphasigen Transformators in einer perspektivischen Darstellung verdeutlicht,

Figur 6

das Gehäuse gemäß Figur 5 in einer Draufsicht zeigt,

Figur 7

das Gehäuse gemäß Figur 5 zusammen mit dem auf einem Haltegestell angeordneten und mit dem Gehäuse verbundenen Ausdehnungsgefäß skizziert,

Figur 8

ein Ausführungsbeispiel eines Kühlmoduls in einer Vorderansicht zeigt,

Figur 9

das mit dem Gehäuse gemäß Figur 5 verbundene Kühlmodul gemäß Figur 8 in einer Draufsicht zeigt,

Figur 10

ein Ausführungsbeispiel eines Zwischenstückes zum Anschluss des Kühlmoduls verdeutlicht,

Figur 11

eine nicht zur Erfindung gehörenden Ausführungsform eines Gehäuses mit angeschlossenem Hilfsstrommodul in einer Seitenansicht zeigt,

Figur 12

das Gehäuse mit eingesteckten Hochspannungsdurchführungen darstellt,

Figur 13, 14, 15

Ausführungsbeispiele von nicht zur Erfindung gehörenden Spannungsauswahleinrichtungen zeigt,

Figur 16

ein nicht zur Erfindung gehörendes Ausführungsbeispiel eines einphasigen Transformators der erfindungsgemäßen Anordnung zeigt, der für eine Eingangsspannung von 345 kV und einer Ausgangsspannung von 138 kV ertüchtigt ist, und

Figur 17

ein nicht zur Erfindung gehörendes Ausführungsbeispiel eines einphasigen Transformators einer der erfindungsgemäßen Anordnung mit einer Eingangsspannung mit 330 kV und einer Ausgangsspannung von 115 kV darstellt.

Further expedient embodiments and advantages of the invention are the subject of the following description of embodiments of the invention with reference to the figures of the drawing, wherein the same reference numerals refer to components with the same effect.

Figures 1, 2

a single-phase transformer of an embodiment of the inventive Show arrangement in perspective view,

Figure 3

schematically illustrates a faulty multiphase transformer during operation,

Figure 4

the arrangement according to the invention as a replacement for the faulty multiphase transformer according to Figure 3 shows,

Figure 5

the housing of a single-phase transformer is shown in a perspective view,

Figure 6

the housing according to Figure 5 in a top view,

Figure 7

the housing according to Figure 5 together with the expansion vessel arranged on a support frame and connected to the housing,

Figure 8

shows an embodiment of a cooling module in a front view,

Figure 9

that with the housing according to Figure 5 connected cooling module according to Figure 8 in a top view,

Figure 10

an example of an intermediate piece for connecting the cooling module is illustrated,

Figure 11

shows an embodiment of a housing with connected auxiliary power module in a side view,

Figure 12

the housing with inserted high-voltage bushings,

Figure 13, 14, 15

shows embodiments of voltage selection devices not belonging to the invention,

Figure 16

shows an embodiment not belonging to the invention of a single-phase transformer of the arrangement according to the invention, which is designed for an input voltage of 345 kV and an output voltage of 138 kV, and

Figure 17

represents an embodiment not belonging to the invention of a single-phase transformer of an arrangement according to the invention with an input voltage of 330 kV and an output voltage of 115 kV.

Figure 1 shows a perspective view of an exemplary embodiment of a single-phase transformer 1 of an arrangement according to the invention. The transformer 1 shown there has a housing 2 which is equipped with a cooling module 3, an expansion vessel 4, an auxiliary power module 5 and high-voltage bushings 6, 7, 8. The components or modules mentioned are detachably connected to one another and can therefore be easily dismantled and transported independently of one another. To protect the high-voltage bushings 6, 7 and 8 and the active part of the transformer 1 arranged in the housing, i.e. the high-voltage winding connected to the high-voltage bushing 6 or 7 as well as the low-voltage winding connected to the high-voltage bushing 8 and the core, the legs of which are enclosed by the respective windings , arresters 9 are used, which have a non-linear resistance within their arrester housing, which changes from a non-conductive state to a conductive state in the event of overvoltages and thus protects the components connected in parallel to it.

The high-voltage bushings 6, 7 and 8 are each designed as plug-in high-voltage bushings and can be inserted with their insertion end into suitable bushing sockets 10. The bushing sockets 10 are designed to be rotationally symmetrical like the insertion end and delimit a cavity that is open towards the housing cover but closed on one side and is designed to be complementary in shape to the insertion end of the respective high-voltage bushing 6, 7, 8. The bushing sockets 10 are also connected to the housing 2 in a fluid-tight manner, so that the oil chamber of the single-phase transformer 1 is hermetically sealed, i.e. air- and liquid-tight, from the outside atmosphere. At the closed end of the bushing socket, a power line bolt (not shown in the figure) is held, which, when the high-voltage bushing 6, 7 or 8 is inserted into the respective bushing socket 10, is in conductive contact with the high-voltage conductor extending through the respective high-voltage bushing 6, 7, 8. The said line bolt extends into the interior of the housing 2, i.e. into its oil chamber, where it is in contact with a winding connection line, which thus electrically connects the bushing socket to the respective high-voltage or low-voltage winding of the transformer 1.

For mounting and fixing the high-voltage bushing 6, 7 or 8, they each have a fastening connection 11. A column section 12 extends from the fastening connection 11 to a high-voltage connection 13, which in the exemplary embodiment shown is an outdoor connection. The distance between the fastening connection 11 and the high-voltage connection 13 is over 2 meters and in particular over 3 meters in the exemplary embodiment shown.

Figure 2 shows the single-phase transformer 1 according to Figure 1 in a perspective view in which the cooling module is better visible. Otherwise, these apply Figure 1 according to the statements made here.

Figure 3 shows a top view of a three-phase transformer 14, which is arranged on a foundation made of concrete 15. On the high-voltage side, the transformer 14 is connected to a high-voltage supply network 16 which has three phases. A consumer network 17 is indicated on the low-voltage side. If the multi-phase transformer 14 fails, the energy supply to the consumer network 17 can no longer be maintained by the supply network 16.

Therefore, it is necessary to ensure that the multiphase transformer 14 can be replaced quickly. However, the multiphase transformer 14 is a power transformer, the individual manufacture of which usually takes several months, for example 10-15 months. In addition, there is the complex transport and finally the assembly on site, which also takes several weeks.

Figure 4 shows the use of an arrangement 18 according to the invention to replace the multi-phase transformer 14. It can be seen that the arrangement 18 consists of several single-phase transformers 1, as in the Figures 1 and 2 shown exists. The single-phase transformers 1 are each connected to the supply network 16 on their high-voltage side, for example with the outdoor connection 13 of the bushing 6, and to the consumer network 17 on their low-voltage side via a cable connection and an outdoor connection. The arrangement 18 according to the invention is designed to be flexible and can therefore be set up according to the respective requirements. The arrangement 18 according to the invention can therefore be built before an error occurs. Due to its modular structure and the use of single-phase transformers 1, the arrangement 18 according to the invention consists of individual components that are light in comparison to the multi-phase transformer 14 and can be transported to the desired installation location in a significantly shorter time. Due to the modular structure, the assembly time is also significantly shortened, so that the arrangement 18 according to the invention can be assembled within a few days and the supply to the consumer network can therefore be resumed quickly. You can then look for a permanent replacement solution for the multi-phase transformer 14. For example, a new multi-phase transformer can be designed and manufactured. The faulty multi-phase transformer 14 can be removed from the foundation 15 and the new multi-phase transformer can be installed there. The supply network 16 and the consumer network 17 are then connected to the new multi-phase transformer, so that this then ensures the desired voltage conversion instead of the arrangement 18 according to the invention. The arrangement 18 according to the invention can then be dismantled and used for new tasks.

Figure 5 shows the housing 2 of a single-phase transformer 1 in a perspective view. Here, the feedthrough sockets 10 are particularly clearly visible. In addition, a pipe 18 is shown, which serves to connect the housing 2 to the cooling module 3. The pipe 18 forms an opening 19, which can be closed fluid-tight by means of a closing valve 20. In addition, a connection piece 21 for connection to the expansion tank 4 is shown.

In Figure 6 is the housing 2 according to Figure 5 shown in a top view. Especially in Figure 6 Adjustment openings 22, 36 are illustrated, which can be closed in a fluid-tight manner by means of a flap. The adjustment openings 22 and 33 each provide access to a selection device, which will be discussed in more detail later. In Figure 6 The pipe 18 has not been shown, so that only a connecting piece 25 can be seen, in which an opening 19 is formed, which can be closed again via a closing valve. An unwanted leakage of insulating liquid from the housing 2 during transport is thus avoided.

Figure 7 shows the housing 2 according to the Figures 5 and 6 , however, the expansion vessel 4 is connected via a pipeline 24 to the connecting piece 21 and thus to the oil chamber of the housing 2. In other words, as temperatures increase, the expanding insulating liquid can reach the expansion vessel 4 via a connection piece 21 and connection pipe 24 comprising a connection. In Figure 7 It can also be seen that the expansion vessel 4 is arranged on a separately set up frame 25. The entire weight of the expansion vessel 4 is thus transferred into the frame 25 and not introduced into the housing 4. The holding frame 25 is connected to the housing 2 via a hook connection, so that unwanted lateral slipping of the holding frame 25 from the housing 2 is avoided. The hook connection comprises a hook part 26 which is firmly connected to the holding frame 25 and which engages in a counterpart fixed to the housing 2. The counterpart is, for example, a bolt that extends parallel to the housing cover and is connected to the housing cover via two side legs, with the side legs and the bolt having the shape of an upside-down "U".

Figure 8 shows the cooling module 3 in a front view, in which it can be seen that the cooling module 3 has fans 27 with which the cooling capacity of the cooling module 3 can be increased. The fans 27 generate an air flow that is guided past the outside of a heat exchange register of the cooling module 3 (not shown in the figure). The insulating liquid circulates within the heat exchange register, whereby a heat exchange occurs between the heated insulating liquid and the air flow flowing past. In other words, heat is transferred from the insulating liquid into the air flow and can thus be dissipated into the outside atmosphere. The cooling module 3 is also held in the frame 25. As already described, the frame 25 forms a hook part 26 for a hook connection to the housing 2, so that the frame 23 and thus the cooling module 3 can be easily hooked onto the housing. The holding frame 25 also forms lifting eyes 46 for lifting with a lifting crane. In addition, the cooling module 3 comprises a control unit 47 which is firmly integrated into the cooling module 3. The fixed connection simplifies and accelerates the assembly of the cooling module 3 on the housing 2.

In Figure 9 It can also be seen that the cooling module 3 forms a connecting piece 28 in its upper area, which is connected to the pipe 18 and thus to the connecting piece 23 of the housing 2 via an intermediate piece 29. The connector 28 forms a coolant inlet of the cooling module 3, whereas pipe 18 forms a coolant outlet of the housing 2. In Figure 8 an output connection 30 can be seen in the lower area of the cooling module, which limits a coolant outlet of the cooling module 3. Via a further intermediate piece 29, the coolant outlet 30 of the cooling module 3 is connected to a coolant inlet of the housing 2, not shown in the figure, in its lower region, so that circulation of insulating liquid can occur via the cooling module 3. The connecting piece 28, the pipeline 18, the outlet connection 30 and the coolant inlet (not shown) of the housing 2 are each equipped with a closing valve 44 with which the respective outlet or inlet can be closed in a fluid-tight manner.

From the Figures 8 and 9 It can also be seen that the cooling module 3 shown is split into two parts, for this reason the connecting piece 28 is connected to a transversely extending upper manifold 31, which in turn is connected to two pipes 32 and 33, so that the cooling can be divided into two cooling lines. Below the fans 27, a lower manifold 34 is in Figure 8 which combines the two insulating liquid streams and supplies them to the outlet nozzle 30.

Figure 9 shows the cooling module 3 from above, whereby it is firmly hooked to the housing 2 by means of a hook connection. It is arranged in the holding frame 25.

The intermediate piece 29 is in Figure 10 explained in detail. It can be seen that the intermediate piece 29 is designed at an angle. It is hollow or tubular inside and defines a connecting channel that can be vented with a vent connection 34. For example, a hose connection can be placed on the vent connection 34, which is connected to an appropriate vacuum pump, so that the connecting channel of the intermediate piece 29, which is between the Closing valves of the pipeline 18 or the connecting piece 28 extends and can be vented. After applying the vacuum, the closing valves can be opened, avoiding contamination of the insulating liquid by air and/or water inclusions. The intermediate piece 29 is also equipped with a drain opening 45 in order to drain insulating liquid from the connecting channel before dismantling.

In the Figure 11 The embodiment shown relates to an embodiment which does not fall under the wording of the claims but is useful for understanding the invention. Figure 11 shows the assembly of the auxiliary power module 5 on the housing 2 by means of a mechanical connection unit 42. The auxiliary power module 5 is connected to a tap of a compensating or tertiary winding of the housing 2 via an electrical connection (not shown in the figure), so that in this way a voltage is applied to the input of the auxiliary power module 5 when the respective single-phase transformer 1 is operating. The auxiliary power module 5 has an auxiliary transformer (not shown in the figure) which is connected with its high-voltage winding to the input of the auxiliary power module 5 and which provides a supply voltage on the output side, which can be used, for example, to drive the fans 27 of the cooling module 5. For this purpose, the auxiliary power module 5 is connected to the cooling module via electrical connecting lines (not shown).

The connection unit 42 is a detachable mechanical connection that allows the auxiliary power module 5 to be connected to the housing 2 easily, quickly and safely. For example, a plug-in, clamp, hook, flange or other connection comes into consideration here.

In Figure 12 is the housing 2 with all pluggable high-voltage bushings 6, 7 and 8, as in Figure 1 shown, clarified. In addition, a redundant cable connection 35 can be seen, which connects two cable conductors enabled. Furthermore, it can be seen that the housing 2 has an output adjustment opening 22 and an input adjustment opening 36. Both the input adjustment opening 36 and the output adjustment opening 22 are closed in a fluid-tight manner by a cover.

The Figures 13 to 17 The embodiments shown do not relate to embodiments that fall under the wording of the claims, but are useful for understanding the invention. In particular, the Figures 13 to 17 illustrate the flexibility of the arrangement 18 and in particular show that the arrangement 18 can be used variably in different voltage levels. In Figure 13 the view into the input setting opening 36 is clear, so that the selection device 37 facing it can be seen. The selection device 37 has voltage connections 38, 39 and 40. Two of the voltage connections 38 and 39 are connected to one another using a U-shaped control conductor 41. This setting connects the high-voltage winding of the transformer 1 to the bushing socket 10 of the high-voltage bushing 6 and thus enables it to handle an input voltage of 345 kV. The output of a voltage of, for example, 138 kV takes place at the high-voltage bushing 8. The high-voltage bushing 7 can be omitted in the operating mode set in this way.

Figure 16 clarifies the design of the housing 2 with cooling module 5, expansion vessel 4 and the two high-voltage bushings 6 and 7, which are adjusted according to an input setting Figure 13 results.

The Figure 14 illustrates a look into the input setting opening 22, whereby a selection device 37 can again be seen with its three voltage connections 38, 39 and 40. In Figure 14 the connecting conductor 41 connects the voltage connections 38 and 39, so that the voltage is output at the high-voltage feedthrough 8. In Figure 15 A position is shown in which the connecting conductor 41 connects the connections 39 and 40 connects together. In the position shown in this way, the voltage at the cable connection 35 drops, so that the high-voltage feedthrough 8 can also be omitted.

In Figure 17 a configuration of the transformer 1 is shown, in which the connecting conductor 41 of the selection device 22 connects the voltage connections 39 and 40. In this setting, the transformer is set up for high voltages of 230 kV, whereby a voltage of 115 kV can be tapped at the high-voltage bushing 8 or at the cable connection.

Claims (5)

1. Arrangement (18) for replacing a multiphase transformer (14) with multiple single-phase transformers (1), each of which has

   - a housing (2) which is filled with an insulating liquid and in which a core with a higher-voltage winding and a lower-voltage winding is arranged,

   - at least one high-voltage leadthrough (6,7,8), and

   - a cooling module (3) which is releasably connectable to the housing (2) and which is filled with insulating liquid and which serves for cooling the insulating liquid, wherein

   both the housing (2) and the cooling module (3) have in each case at least one cooling-liquid inlet (28) and at least one cooling-liquid outlet (18), which are connectable to one another for exchange of insulating liquid,

   characterized by

   at least one leadthrough plug-in bushing (10) which is connected to the higher-voltage winding or lower-voltage winding via a winding connection line which extends within the housing (2), wherein the high-voltage leadthrough (6,7,8) is pluggable into the leadthrough plug-in bushing (10), and an intermediate piece (29) for fluid-tight connection of cooling-liquid outlet (18) and cooling-liquid inlet (28), wherein each cooling-liquid outlet (18) and each cooling-liquid inlet (28) is equipped with a fluid-tight closing valve, and wherein the intermediate piece (29) delimits a connecting channel and has a deaeration opening (34) for deaeration of the connecting channel.
2. Arrangement (18) according to Claim 1,
   characterized by
   an expansion vessel (4) which is connectable to the housing (2) via a connection (24) for exchange of insulating liquid and which is arranged on a separate holding frame (25).
3. Arrangement (18) according to Claim 2,
   characterized in that the holding frame (25) is configured for holding the expansion vessel (4) above the cooling module (3), which is releasably fastened to the housing (2).
4. Arrangement (18) according to one of the preceding claims, characterized in that at least three leadthrough plug-in bushings (10) are provided.
5. Method for replacing a multiphase transformer (14) by means of an arrangement according to one of the preceding claims, in which a number of single-phase transformer housings (2), which number corresponds to the number of phases of the multiphase transformer (14), are set up in the vicinity of the multiphase transformer (14), the windings of the single-phase transformer housings (2) are interconnected, the transformer housings (2) are releasably connected to a cooling module (3), the high-voltage leadthroughs (6,7,8) are fitted into leadthrough plug-in bushings (10) of the transformer housing (2), and the high-voltage leadthroughs (6,7,8) are connected at their connections (13) to a supply network (16) and to a load (17).

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