EP4627605A1

EP4627605A1 - Method and transformer arrangement for handling transportation and assembling of a single phase transformer

Info

Publication number: EP4627605A1
Application number: EP23809265.4A
Authority: EP
Inventors: Erik Carl WEDIN; Peter Astrand; Mattias VIKSTEN; Erik LYSELL
Original assignee: Hitachi Energy Ltd
Current assignee: Hitachi Energy Ltd
Priority date: 2022-12-01
Filing date: 2023-11-23
Publication date: 2025-10-08
Also published as: CN120303751A; WO2024115269A1; EP4379758A1

Abstract

A method for handling transportation and assembling of a single phase transformer. The single phase transformer is divided into two or more active parts (14). The two or more active parts (14) are transported to a site in at least two separate tanks (10). The single phase transformer is then assembled by connecting the tanks (10) together electrically at the site, wherein the tanks (10) are connected electrically by one or more leads. At least one of the tanks (10) comprises a tertiary winding and at least one of the tanks (10) does not comprise a tertiary winding, and wherein the tertiary winding supplies power to a separate voltage system.

Description

METHOD AND TRANSFORMER ARRANGEMENT FOR HANDLING

TRANSPORTATION AND ASSEMBLING OF A SINGLE PHASE TRANSFORMER

FIELD OF THE INVENTION

Embodiments herein relate to the field of transformers. In particular, the embodiments herein relate to handling transportation and assembling of a single phase transformer.

BACKGROUND

A power transformer is equipment used in an electric grid of a power system. Power transformers transform voltage and current in order to transport and distribute electric energy. Power transformers are in some cases very large and may not be possible to transport to some locations. Because of this, it is useful if the size of the largest transportable part of the transformer is reduced.

One way of solving this problem is that the transformer is disassembled at a factory and transported to a site in pieces. The transformer is then assembled at the site. This has the disadvantage that it needs, e.g. requires, facilities and resources on site to carry out the assembly. It is also challenging to ensure the quality as it is difficult to perform high voltage testing on site. High voltage testing after assembly on site is normally not carried out with this technology.

Another way of solving the problem is to use parallel units. The power rating required is divided in sever smaller units and each unit is shipped to the site. One disadvantage of this is that each transformer requires its own installation on site, including e.g. foundation, fire walls, and electrical connections, including bushings on the transformers. This will drive both cost and footprint for transformers and for the site.

Yet another approach to solve the problem for three-phase transformers is by using a special three phase arrangement. A three phase unit is divided into three single phase active parts, each transported to site in a separate tank. The three tanks are located together on the same foundation at site and are normally connected together with leads in oil ducts. The disadvantage of this solution is that it is does not sufficiently reduce the transport size of the single phase tank, which may be too large to transport. Also, if spare units are required, the full three phase transformer, i.e. , three single phase tanks, are normally needed for the spare units.

JP H06101410 B2 relates to a single phase transformer with a load-ratio adjuster. Unit transformers 1A and 1 B constituting a single phase transformer are arranged in parallel so that the longitudinal sides thereof oppose each other. High voltage bushing 16 and low voltage bushing 17 are horizontally provided in parallel with the longitudinal direction of the unit transformers so that both bushings oppose each other. The load-ratio adjusters 3A and 3B are arranged on both sides of the bushing 17. In this arrangement, the space can be effectively utilized, the bushings 16 and 17 can be provided at the lower locations, and the strength against the earthquake can be increased.

JP H06251951 A relates to a method for minimizing an on-scale connecting operation and improving insulation characteristics. A high voltage lead is led out from both sides of a transformer tank and connected to a high voltage bushing, and medium voltage leads are connected in such a manner that the upper and the lower lead wires of each winding, to be parallel connected between other windings different from the windings where the high voltage leads are connected, are collectively connected.

JP S59210622 A discloses facilitating separation and connection between the respective unit transformers of a split transformer by a method wherein the parts of respective unit transformer tanks to be penetrated by the terminal conductors of windings are demarcated by insulating spacers, and space between the adjoining spacers is connected by a connecting duct containing conductors and encapsulating insulating gas.

JP S57133609 A discloses reducing the time required for installation of a transformer in the field by a method wherein the transformer tank is split into a plurality of units of transportation and each unit is horizontally moved using a rolling member inserted between the tank and base beam, and at the same time, the leads of each unit of transportation are connected with another lead using a sliding contact. JP S58124215 A discloses improving the assembling workability of a split transformer by assembling leads and insulating barriers, manufacturing a connecting duct structure that protecting covers are mounted on the holes of both ends, removing the cover at the time of assembling the transformer, mounting it on a tank of the unit transformer, and connecting the leads to coil leads.

JP S62229909 A discloses minimizing charged quantity and discharged quantity of insulating oil and facilitating changeover from parallel operation to single operation by a method wherein an isolated oil layer is provided in a cable chamber in which connecting lead wires which are connected to a cable through an insulating spacer are installed and a conservator is connected to the isolated oil layer through a valve.

JP H09312216 A discloses providing an oil immersed split electric device which is easy to reassemble at a field, without deteriorating the characteristics due to reassembly and superior in safety.

The present disclosure presents an improved viable solution of a method and transformer arrangement.

SUMMARY

It is an object of embodiments herein to enhance transportation and assembling of a single phase transformer.

According to an aspect the above-mentioned object is achieved by providing a method performed by a transformer arrangement for handling transportation and assembling of a single phase transformer. The single phase transformer is divided into two or more active parts. The two or more active parts are transported to a site in at least two separate tanks. The single phase transformer is then assembled by connecting the tanks together electrically at the site, wherein the tanks are connected electrically by one or more leads.

According to some embodiments, the tanks may be located on a same foundation at the site. According to some embodiments, at least two of the tanks may not be separated by fire walls.

According to some embodiments, at least two of the tanks may have different electrical properties.

According to some embodiments, at least one of the tanks may comprise a regulating winding to regulate a voltage and at least one of the tanks does not comprise a regulating winding.

According to some embodiments, at least two of the tanks may be connected in series.

According to some embodiments, at least two of the tanks may be connected in parallel.

According to some embodiments, the tanks may be connected on a primary side of the single phase transformer and/or on secondary sides of the single phase transformer.

According to some embodiments, the tanks may share a same common cooling equipment.

According to some embodiments, at least two of the tanks may be mechanically connected. According to some embodiments, the mechanical connection may be performed in such a way that allows the at least two tanks to be transported in connected state at the site.

According to some embodiments, at least one of the tanks may comprise a tertiary winding and at least one of the tanks may not comprise a tertiary winding.

According to another aspect the object is also achieved by providing a transformer arrangement. The transformer arrangement comprises a single phase transformer and two or more tanks. The transformer arrangement is configured to divide the single phase transformer into two or more active parts and transport the two or more active parts to a site in at least two separate tanks. The transformer arrangement is further configured to assemble the single phase transformer by connecting the tanks together electrically at the site, wherein the tanks are connected electrically by one or more leads.

According to yet another aspect the object is also achieved by providing a single phase transformer. The single phase transformer is configured to be divided into two or more active parts, wherein the two or more active parts are transported to a site in at least two separate tanks. The single phase transformer is further configured to be assembled by connecting the tanks together at the site, and wherein the tanks are connected electrically by one or more leads.

Embodiments herein are based on the realisation that by dividing the single phase transformer into at least two active parts which are transported to the site in at least two separate tanks, the transportation size of the single phase transformer is significantly reduced. Furthermore, as the single phase transformer then can be assembled by connecting the tanks together electrically at the site the assembly is handled in a more efficient manner. Thereby the transportation and assembling of a single phase transformer is enhanced.

BRIEF DESCRIPTION OF THE FIGURES

Further technical features of the invention will become apparent through the following description of one or several exemplary embodiments given with reference to the appended figures, where:

Fig. 1 is a schematic overview depicting a transformer arrangement, according to embodiments herein;

Fig. 2 is a flowchart depicting a method according to embodiments herein;

Fig. 3 is a schematic overview depicting a transformer arrangement, according to some embodiments herein; and

Fig. 4 is a schematic overview according to some embodiments.

It should be noted that the drawings have not necessarily been drawn to scale and that the dimensions of certain elements may have been exaggerated for the sake of clarity. DETAILED DESCRIPTION

A transformer arrangement 20 according to embodiments herein is illustrated in Fig. 1. The transformer arrangement 20 is configured to divide, e.g. separate, a single phase transformer into two or more active parts 14. The active part 14 of the single phase transformer when used herein is the core, the windings, and the electrical insulation between the windings of the single phase transformer. The two active parts 14 may be placed in at least two separate tanks 10, e.g. transformer tanks. The at least two separate tanks 10 are connected electrically by one or more leads and may be mechanically attached together. The two or more active parts 14 are then transported to a site in the at least two separate tanks 10. When at the site, the single phase transformer is assembled by connecting the tanks 10 together electrically. If a voltage regulating system is used in the transformer arrangement it may be possible to enable it by using a common On-Load Tap Changer (OLTC) or a common OLTC drive unit. This means that at least some tanks 10, may be reduced in size and that the number of components can be reduced. According to some embodiments, a fully assembled spare single phase unit comprising the at least two separate tanks 10 with the active parts 14, installed at the site, may be provided at the site as a backup. Access to a fully assembled spare unit reduces the replacement time in case of a failure in one of the single phase transformers that are in operation.

The method actions for handling transportation and assembling of a single phase transformer, according to embodiments herein, will now be described with reference to a flowchart depicted in Fig. 2. The actions do not have to be taken in the order stated below but may be taken in any suitable order.

Action 201.

To significantly reduce the transportation size of the single phase transformer, the single phase transformer is first divided into two or more active parts 14. Thereby, certain transportation modes may be enabled. Accordingly, transportation of the single phase transformer can be significantly simplified, leading to reduced costs. Furthermore, in some cases, transport of a full size single phase unit may not be possible at all and measure to reduce the size is necessary. Action 202.

The two or more active parts 14 are then transported to a site in at least two separate tanks 10. The at least two tanks 10 with the active parts 14 may be seen as a unit such as a transportation unit and may be referred to as a single phase unit. The tanks 10 may be transported by one or more vehicles, such as lorries.

According to some embodiments, at least two of the tanks 10 may have different electrical properties. This is advantageous/useful because it may, under certain conditions, allow for a decrease in size of the largest transportable part or it may, under certain conditions, allow for a decrease in total number of active parts and tanks. In some conditions, it may also reduce the cost of the single phase transformers as the active parts 14 can be more specialised. Furthermore, the reliability of the single phase units may be improved because fewer components, for example regulating windings, tertiary windings and/or tap changers, may be required with less overall risk for failures as a consequence.

At least two of the tanks 10 may be mechanically connected. The mechanical connection may be performed in such a way that allows the at least two tanks 10 to be transported in connected state at the site, i.e. inside the site. Thus, the at least two of the tanks 10 may not be connected during transport to the site, but they may be moved connected within the site. This is a great advantage if needing to replace a unit in operation with a fully assembled spare unit in short time. This is a great advantage if needing to replace a unit in operation with a spare unit. The spare unit can in such case be fully assembled prior to the replacement procedure which will reduce the time to put the spare unit into operation.

According to some embodiments, at least one of the tanks 10 may comprise a regulating winding to regulate a voltage and at least one of the tanks 10 does not comprise a regulating winding. This is advantageous/useful because it may, under certain conditions, allow for a decrease in size of the largest transportable part or it may, under certain conditions, allow for a decrease in total number of active parts and tanks. Furthermore, the reliability of the single phase units may be improved because fewer components, such as tap changers and regulating windings, are required. According to some embodiments, the at least one of the tanks 10 that comprises the regulating winding may not be connected to a primary side or secondary side of the transformer.

According to some embodiments, the at least one of the tanks 10 that comprises the regulating winding may be connected to one of the primary side and the secondary side, but not connected to both. According to some embodiments, the at least one of the tanks 10 that comprises the regulating winding may be connected to both the primary side and the secondary side.

According to some embodiments, at least two of the tanks 10 may be connected in series. This is advantageous because it may, under certain conditions, allow for a decrease in size of the largest transportable part or it may, under certain conditions, allow for a decrease in total number of active parts and tanks. Furthermore, the reliability of the single phase units may be improved, and cost may be reduced because some parts may be exposed to a lower voltage level.

According to some embodiments, at least two of the tanks 10 may be connected in parallel. This is advantageous because it allows for less complex design as each part can be made with the same or similar design. Furthermore, in some implementations the reliability can be increased as some of the parallel parts may be operated even with failures on other parallel parts. The at least two of the tanks 10 may be connected both in parallel and in series.

According to some embodiments, the tanks 10 may be connected on a primary side, of the transformer. This is advantageous because it allows for a single connection towards the external primary voltage system, which may reduce overall size and cost of the transformer arrangement 20, including size of transformer tanks 10, transformer foundation and transformer booth. Furthermore it may improve the reliability of the single phase transformer because fewer components, for example bushings, may be required.

According to some embodiments, the tanks 10 may be connected on secondary sides of the transformer. This is advantageous because it allows for a single connection towards the external secondary voltage system, which may reduce overall size and cost of the transformer arrangement 20, including size of transformer tanks 10 and transformer booth. Furthermore it may improve the reliability of the transformer because fewer components, for example bushings, may be required.

According to some embodiments, the tanks 10 may be connected on the primary side and the secondary sides of the transformer. This is advantageous because it allows for a single connection towards the external primary and secondary voltage system, which may reduce overall size and cost of the transformer arrangement, including size of transformer tanks 10 and transformer booth. Furthermore it may improve the reliability of the transformer because few components, for example bushings, is required.

Thus, the tanks 10 may be connected on the primary side of the single phase transformer and/or on secondary sides of the single phase transformer.

According to some embodiments, at least two of the tanks 10 may comprise a separate cooling equipment and/or at least two of the tanks 10 may comprise a common cooling equipment. According to some embodiments, the tanks 10 may share a same common cooling equipment. This is advantageous because the overall size, cost and complexity of the transformer arrangement, including cooling control and size of the transformer booth may be reduced.

According to some embodiments, at least one of the tanks 10 may comprise a tertiary winding and at least one of the tanks 10 may not comprise a tertiary winding.

According to some embodiments, the tanks 10 may be aligned in a row and a three phase bank may be constructed by aligning the single phase side by side such that the rows are parallel to each other.

According to some embodiments, the tanks 10 are aligned side by side with the long side of the tanks facing each other.

According to some embodiments, at least one of the tanks 10 may comprise a tertiary winding and at least one of the tanks 10 may not comprise the tertiary winding.

Action 203.

The single phase transformer is then assembled by connecting the tanks 10 together electrically at the site, wherein the tanks 10 are connected electrically by one or more leads, e.g. in oil or fluid.

According to some embodiments, the tanks 10 may be located, e.g. connected together electrically, on a same foundation at the site. This is advantageous because it reduces the required footprint and cost of civil construction at site. At least two of the tanks 10 may not be separated by fire walls

By adopting the embodiments herein as described above, the size and weight of the single phase transformer to be transported, e.g. each transport unit, can be significantly reduced.

Embodiments herein such as mentioned above will now be further described and exemplified. The text below is applicable to and may be combined with any suitable embodiment described above.

A transformer arrangement 20 according to some embodiments is illustrated in Fig. 3. At least two tanks 10 may be mechanically attached together, are connected electrically in oil by one or more leads, e.g. in oil or fluid ducts, and are transported to the site. At least one of the tanks 10 may comprise a regulating winding to regulate a voltage and at least one of the tanks 10 may not comprise a regulating winding. The at least one of the tanks 10 may comprise the regulating winding to regulate the voltage is marked with an X in Fig. 3. Accordingly, at least one tank 10 may contain regulation. At least one of the tanks 10 may comprise a tertiary winding to supply power to a separate voltage system and at least one of the tanks 10 may not comprise a tertiary winding. Providing tertiary windings in less than all tanks may reduce the cost because less total number of tertiary windings are required, which may also improve the reliability of the single phase transformer. Fig. 3 shows four tanks 10 connected in parallel, wherein three of the tanks 10 may be connected in parallel as main single phase transformer, and wherein all four tanks 10 may be referred to as a single phase unit.

A transformer arrangement 20 according to some embodiments is illustrated in Fig. 4. The figure shows an example with three series connected units, e.g. three series connected tanks 10 comprising the active parts 14 of the single phase transformer. However, it does not necessarily have to be three unit in series, it may be any number from two and above. The three tanks 10 may be connected mechanically and have electrical connection in oil. In some implementations, for example a Y connected transformer, the series connected units have advancingly lower voltage. According to one implementation, the tap changer is located in the unit with the lowest voltage. It is to be noted that any feature of any of the aspects may be applied to any other aspect, wherever appropriate. Likewise, any advantage of any of the aspects may apply to any of the other aspects. Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to "a/an/the element, apparatus, component, means, step, etc." are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, step, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated. The use of “first”, “second” etc. for different features/components of the present disclosure are only intended to distinguish the features/components from other similar features/components and not to impart any order or hierarchy to the features/components. It will be appreciated that the foregoing description and the accompanying drawings represent non-limiting examples of the method taught herein. As such, techniques taught herein are not limited by the foregoing description and accompanying drawings. Instead, the embodiments herein are limited only by the following claims and their legal equivalents.

Claims

1. Method for handling transportation and assembling of a single phase transformer, wherein the method comprises: dividing (201) the single phase transformer into two or more active parts (14); transporting (202) the two or more active parts (14) to a site in at least two separate tanks (10); and assembling (203) the single phase transformer by connecting the tanks (10) together electrically at the site, wherein the tanks (10) are connected electrically by one or more leads, wherein at least one of the tanks (10) comprises a tertiary winding and at least one of the tanks (10) does not comprise a tertiary winding, and wherein the tertiary winding supplies power to a separate voltage system.

2. The method according to claim 1 , wherein the tanks (10) are located on a same foundation at the site.

3. The method according to claim 1 or 2, wherein at least two of the tanks (10) are not separated by fire walls.

4. The method according to any one of claims 1-3 , wherein at least two of the tanks (10) have different electrical properties.

5. The method according to any one of claims 1 -4, wherein at least one of the tanks (10) comprises a regulating winding to regulate a voltage and at least one of the tanks (10) does not comprise a regulating winding.

6. The method according to any one of claims 1-5, wherein at least two of the tanks (10) are connected in series.

7. The method according to any one of claims 1-5, wherein at least two of the tanks (10) are connected in parallel.

8. The method according to any one of claims 1-7, wherein the tanks (10) are connected on a primary side of the single phase transformer and/or on secondary sides of the single phase transformer.

9. The method according to any one of claims 1 -8, wherein at least two of the tanks (10) comprise a separate cooling equipment and/or at least two of the tanks (10) comprise a common cooling equipment.

10. The method according to any one of claims 1-9, wherein at least two of the tanks (10) are mechanically connected.

11. The method according to claim 10, wherein the mechanical connection is performed in such a way that allows the at least two tanks (10) to be transported in connected state at the site.

12. A transformer arrangement comprising a single phase transformer and two or more tanks (10), wherein the transformer arrangement is configured to: divide the single phase transformer into two or more active parts (14); transport the two or more active parts (14) to a site in at least two separate tanks (10); and assemble the single phase transformer by connecting the tanks (10) together electrically at the site, wherein the tanks (10) are connected electrically by one or more leads, wherein at least one of the tanks (10) comprises a tertiary winding and at least one of the tanks (10) does not comprise a tertiary winding, and wherein the tertiary winding is configured to supply power to a separate voltage system.

13. The transformer arrangement according to claim 12, wherein the transformer arrangement is configured to perform the method according to any one of claims 2-11.

14. A single phase transformer, configured to be divided into two or more active parts (14), wherein the two or more active parts (14) are transported to a site in at least two separate tanks (10), and wherein the single phase transformer is assembled by connecting the tanks (10) together at the site, and wherein the tanks (10) are connected electrically by one or more leads, wherein at least one of the tanks (10) comprises a tertiary winding and at least one of the tanks (10) does not comprise a tertiary winding, and wherein the tertiary winding is configured to supply power to a separate voltage system.