TRANSPORTABLE POWER TRANSFORMER UNIT

Abstract

A power transformer unit includes at least one single-phase transformer for connection to a high-voltage network. Each single-phase transformer includes a tank filled with insulating fluid receiving a core having high and low-voltage windings, at least one bushing socket connected to the high or low-voltage winding by a winding connection cable inside the tank, at least one high-voltage bushing to be inserted into the bushing socket, cooling equipment for the fluid and an expansion vessel compensating for temperature-induced volume fluctuations of the fluid. To transport the power transformer unit as quickly as possible and to put the power transformer unit into operation in situ, the expansion vessel and the cooling equipment are mechanically firmly connected to the tank and together with the tank and each bushing socket form a transport unit having an external contour lying inside a predetermined transport profile.

Claims

1-14. (canceled)

15. A power transformer unit, comprising: at least one single-phase transformer configured for connection to a high-voltage grid, each single-phase transformer including: a tank to be filled with an insulating fluid for receiving a core with a high-voltage and low-voltage winding; at least one bushing socket to be connected by a winding connection line extending inside said tank to the high-voltage or low-voltage winding; at least one high-voltage bushing to be inserted into said at least one bushing socket; cooling equipment for cooling the insulating fluid; an expansion vessel for compensating for temperature-induced volume fluctuations of the insulating fluid; said expansion vessel and said cooling equipment being mechanically fixedly connected to said tank; and a transport unit formed of said expansion vessel, said cooling equipment, said tank and each bushing socket, said transport unit having an external contour lying inside a predefined transport profile.

16. The power transformer unit according to claim 15, wherein said transport unit has a height less than 4.2 m, a width less than 3.3 m and a length less than 9 m.

17. The power transformer unit according to claim 15, wherein said transport unit includes at least one motor drive, sensor units and at least one protection and monitoring device.

18. The power transformer unit according to claim 15, wherein said expansion vessel is box-shaped, extends in a longitudinal direction, and has a height between 20 cm and 250 cm.

19. The power transformer unit according to claim 18, wherein said expansion vessel has a width being less than two thirds of a width of said tank.

20. The power transformer unit according to claim 19, wherein said expansion vessel has a length being greater than three quarters of a length of said tank.

21. The power transformer unit according to claim 15, wherein said tank and said expansion vessel each extend in a respective longitudinal direction, and said longitudinal directions run parallel to one another.

22. The power transformer unit according to claim 15, wherein said tank includes two mutually-opposite longitudinal faces and two mutually-opposite end faces being connected to said longitudinal faces and having a shorter width than said longitudinal faces, and said cooling equipment is disposed at least at one of said end faces.

23. The power transformer unit according to claim 22, wherein said cooling equipment includes two cooling units each disposed at a respective one of said end faces.

24. The power transformer unit according to claim 15, wherein said expansion vessel extends above and parallel to said tank, and said expansion vessel is spaced apart from said tank with a clearance of between 1 cm and 50 cm.

25. The power transformer unit according to claim 15, wherein said cooling equipment includes an inlet and an outlet both opening into said cooling equipment from underneath said cooling equipment.

26. The power transformer unit according to claim 15, wherein said tank has a cover, and said bushing sockets are disposed in said cover.

27. The power transformer unit according to claim 15, wherein the windings include an aramid insulation.

28. The power transformer unit according to claim 15, wherein the insulating fluid is an ester oil.

Description

[0025] Further expedient embodiments and advantages of the invention are the subject matter of the following description of exemplary embodiments of the invention with reference to the figures of the drawing, wherein the same reference signs refer to components having the same effect, wherein

[0026] FIG. 1 shows a perspective view of an exemplary embodiment of a single-phase transformer of the power transformer unit according to the invention,

[0027] FIG. 2 shows a side view of the single-phase transformer according to FIG. 1,

[0028] FIG. 3 shows a plan view of the single-phase transformer according to FIG. 2,

[0029] FIG. 4 shows the transport unit of a single-phase transformer according to FIG. 1 with transport profile and

[0030] FIG. 5 shows a plan view of the transport unit according to FIG. 4.

[0031] FIG. 1 shows an exemplary embodiment of a single-phase transformer 1, of a power transformer unit according to the invention, which, in addition to the single-phase transformer 1 shown in FIG. 1, also comprises two further single-phase power transformers 1 of identical design. Each single-phase transformer 1 serves for the connection of one phase of a three-phase supply grid carrying alternating voltage that here lies at a high-voltage potential of 335 kV.

[0032] The single-phase transformer 1 shown in FIG. 1 has a tank 2 that comprises a side wall 3 facing towards the observer and an end face 4 that is likewise facing towards the observer. An appropriately dimensioned side wall 5, not visible in FIG. 1, lies opposite the side wall 3, whereas an appropriately dimensioned end face 6 lies opposite the end face 4. In addition, the tank 2 has a cover 7 that closes it impermeably from above. The floor of the tank 2 is not shown on the drawing in FIG. 1.

[0033] The single-phase transformer 1 further comprises cooling equipment that consists of two cooling units 8 and 9, wherein the cooling unit 8 is firmly connected to the tank 2 at the end face 4 and the cooling unit 9 is firmly connected to the tank 2 at the end face 6. Each cooling unit 8 or 9 is fitted with fans 10 which, when required, generate a flow of air to increase the cooling capacity of the respective cooling unit 8, 9.

[0034] Each cooling unit 8, 9 is connected via an inlet 11 and an outlet 12 to the interior of the tank 2 which is filled with an insulating fluidan ester oil in this case. It can be seen here that both the inlet 11 and the outlet 12 lead to the respective cooling unit 8 or 9 from underneath the latter.

[0035] A compensation vessel 13 extends above the tank 2 and is likewise connected via a connecting line 14 to the interior of the tank 2. Like the tank 2, the expansion vessel 13 extends in a longitudinal direction, wherein the longitudinal direction of the expansion vessel 13 and the longitudinal direction of the tank 2 run parallel to one another. The expansion vessel 13 here is essentially box-shaped and in particular flat, and has a height of about 1 m, wherein the distance between the cover 7 and the bottom face, not illustrated on the figure, of the expansion vessel 13 is about 10 cm. The important point is that the mouth of the inlet 11 is arranged underneath the mouth of the connecting line 14, so that it is ensured that the level to which the tank 2 is filled with insulating fluid is always above the entrance opening of the inlet 11.

[0036] Bushing sockets 15 are arranged in the cover 7 and are connected impermeably to the tank 2. Each bushing socket 15 forms a fastening flange for this purpose, against which it is firmly pressed onto the cover 7 of the tank 2. Expedient screwed joints, for example, are used for this purpose. In order to fasten the bushing socket 15 to the tank 2 in an airtight and fluidtight manner, sealing means shown on the drawing, which are clamped between the cover 7 and the fastening flange, are necessary. Each bushing socket 15 further comprises a receptacle section, not shown on the drawing, consisting of an electrically non-conductive, insulating material. The receptacle section tapers here toward a closed end. At the closed end, the wall of the receptacle section is penetrated by a bolt-shaped, electrically conductive contact piece. The contact piece is connected at its section that penetrates into the interior of the tank 2 to a winding connection line which extends inside the tank 2 to a winding that is arranged in the tank. Said winding is coupled inductively via a magnetizable core to a further winding.

[0037] A high-voltage bushing 16, 17, 18 is inserted in each case into each bushing socket 15 in FIG. 1. These each have an insertion section on the insertion side, whose shape is designed to be complementary to said receptacle section of the bushing socket 15, so that the two components come to lie against one another with a close fit, and air or other enclosures are avoided. At its side that faces away from said insertion section, each high-voltage bushing 16, 17, 18 is fitted with an outdoor terminal 19.

[0038] The single-phase transformer 1 further has two cable outlets 20 that are configured to receive a cable plug. The cable outlets 20 are redundant, so that if one cable outlet 20 fails, the energy supply to the consumers downstream from the transformer 1 is ensured through the still-intact cable outlet 20.

[0039] The transformer 1 is illustrated with three high-voltage bushings 16, 17 and 18 in FIG. 1. The high-voltage bushing 16 serves for the connection of an air-insulated phase conductor of a high-voltage supply grid with a voltage of 335 kV. The single-phase transformer 1 can now be adjusted so that it outputs the output voltage via the high-voltage bushing 17 or 18, wherein the output voltage is, for example, 138 kV or 134 kV. It is obvious that in this case only one output-side high-voltage bushing 17 or 18 is required, and the other high-voltage bushing does not have to be inserted into the associated bushing socket 15. It is, furthermore, also possible to apply the output voltage to the cable outlets 20, so that both high-voltage bushings 17 or 18 can be omitted. It is, finally, also possible, for example with input voltages of 245 kV, to omit the high-voltage bushing 16, wherein the high-voltage bushing 17 serves as the input for the connection of the air-insulated 245 kV conductor.

[0040] A device box 21 and a control unit 22 can be seen next to the cooling unit 8 at the end face 4, which are fastened to the tank 2 on both sides of the cooling unit 8. The tank 2 is extended in the rear region by a convexity 23 at the end face 6, which is used to accommodate the bushing socket 15 for the high-voltage bushing 16. The cooling unit 9 can be seen offset to the side next to the convexity 23.

[0041] FIG. 2 shows a side view of the single-phase transformer 1 according to FIG. 1, in which the convexity 23 somewhat covers the cooling unit 8 arranged behind it, so that only the fans 10 can be seen. The expansion vessel 13 is displaced to the left with respect to the tank 2 and extends over and beyond the cover 7 of the tank 2, and protrudes here over the inlet 11 of the cooling unit 8 that extends from its inlet opening arranged above at the tank 2, under the device box 21, through to the entrance opening of the cooling unit 8.

[0042] FIG. 3 shows a plan view of the single-phase transformer 1, from which the connecting line 14 is particularly easily recognized. It is also shown that the expansion vessel 13 has a ventilation line 24 that is fitted with an air drying installation in order to enable the supply of dry air to the expansion vessel 13 at its end facing away from the expansion vessel 13.

[0043] FIG. 4 shows a transport unit 25 of the single-phase transformer 1 according to FIG. 1, 2 or 3, comprising all the components of the single-phase transformer 1, with the exception of the high-voltage bushing 16, 17 and 18. A transport profile 26 is moreover illustrated, which should clarify the maximum permissible size of transported items in road traffic. It can be seen that the transport unit 25 does not protrude beyond the maximum permissible transport profile 26.

[0044] This is achieved firstly in that all of the componentswith the exception of the bushings 16, 17, 18are mounted at the end faces 4 or 6. In addition, the expansion vessel 13 is of flat design, wherein the accesses, that is both the inlet and the outlet to the respective cooling units 8 and 9, are arranged underneath the respective cooling unit 8 and 9.

[0045] FIG. 5 shows an end view of the transport unit 24 as well as the associated transport profile 25. Here it can also be seen that the transport unit 25 lies within the transport profile 26, and is thus permitted for road transport.