Use of a ceramic spring to preload a component of a high-voltage assembly

Abstract

The invention relates to a use of a ceramic spring (1) for prestressing a component of a high-voltage assembly (2), wherein the ceramic spring (1) is arranged in an electrical field of a high voltage of the high-voltage assembly (2), in particular prestressing a high-voltage-carrying component (7) of the high-voltage assembly (2).

Description

[0001] The present invention relates to a use of a ceramic spring for prestressing a component of a high-voltage assembly according to claim 1, a ceramic spring module for prestressing a component of a high-voltage assembly and for use in a high-voltage electric field according to claim 5, a high-voltage assembly according to claim 11 and a method for producing a high-voltage assembly according to the preamble of claim 14.

[0002] In high-voltage technology, components are sometimes prestressed with great force. For example, this is the case with power transformers, where the windings of the coils are prestressed against each other to prevent them from oscillating in the alternating field. If the coils were to oscillate, they would wear away their insulation and cause a short circuit. This prestressing is currently achieved by pressing the coils into a frame using blocks of chipboard or resin-filled plywood, applying great force. However, the prestress applied in this way is quickly lost in the windings, which are usually made of copper, aluminum, and insulation materials such as cellulose and resin-filled plywood. This means that it can already have fallen to 30% to 50% of its initial value during testing or transport of the transformer.Mechanical accelerations and vibrations during transport and later during operation of the transformer can lead to relative movements of the windings, which reduces the service life of the transformer and can cause significant damage in the event of a short circuit between turns.

[0003] In this and other applications, it would be advantageous to be able to use elastic materials. However, due to the strong electric fields, steel springs are not suitable for use near windings or near live parts. This problem has long been unsolved.

[0004] The invention is based on the problem of finding a solution to this problem.

[0005] The above problem is solved by the features of claim 1.

[0006] The fundamental idea is that ceramic springs can be used to generate and maintain preloads in the high-voltage range without inducing large eddy currents, as is the case with steel springs. This is based on the finding that zirconium dioxide, for example, in partially stabilized form has a similar modulus of elasticity to that of steel. There are fundamental prejudices against the use of ceramics, as they are perceived as brittle and inelastic. Once these prejudices are overcome, however, it becomes clear that although ceramics present different challenges than steel, they can be easily solved.

[0007] In particular, a use of a ceramic spring for prestressing a component of a high-voltage assembly is proposed, wherein the ceramic spring is arranged in an electrical field of a high voltage of the high-voltage assembly, in particular prestressing a high-voltage-carrying component of the high-voltage assembly.

[0008] Claim 2 relates to various designs of the high-voltage assembly in which ceramic springs can be used particularly advantageously. For transformers in the multi-MVA range, the preload of the coils (winding compression) can range between 20 tons and 160 tons per phase, depending on the size of the transformer. These compressions are often distributed across four to eight pressboard blocks or blocks of synthetic resin-filled plywood. If the winding compression decreases too much, high costs arise as a result of failures, sometimes catastrophic. The advantages of using ceramics are permanent pressure during the drying process in the furnace at the transformer manufacturer (isostatic compression), permanent pressure on the windings during operation, and the electrical neutrality of the ceramic, which reduces the risk of partial discharges, flashovers, and localized heating.

[0009] In a particularly preferred embodiment according to claim 3, the ceramic spring is a ceramic disc spring. This can be interconnected with other ceramic disc springs to form a disc spring assembly, particularly in the form of a disc spring column. Disc springs combine high spring force with short spring travel.

[0010] These embodiments are further developed according to claim 4 in that a coil of the transformer is preloaded by one or more disc spring assemblies. These disc spring assemblies are preferably part of a ceramic spring module and connected in parallel within it. The ceramic spring module can also serve as a size-related replacement for the pressboard blocks, thus eliminating the need for adjustments to the rest of the transformer.

[0011] According to a further teaching according to claim 5, which has independent significance, a ceramic spring module for prestressing a component of a high-voltage assembly and for use in an electrical field of a high voltage is claimed, wherein the ceramic spring module has a multi-part housing, wherein at least one ceramic spring is arranged in the housing, wherein the housing has a first housing part and a second housing part which is adjustable relative to the first housing part, wherein the first housing part and the second housing part are adjustable from a zero position against a spring force of the ceramic spring against each other into a compression position in which the ceramic spring is loaded with pressure, wherein the ceramic spring module is designed to be individually handleable, preferably wherein the first housing part and the second housing part are secured in the compression position by a releasable securing device.The ceramic spring module is used to dissipate the spring force of the ceramic spring and to easily use the ceramic springs in individual applications.

[0012] Reference may be made to all statements regarding the proposed use. Reference may also be made to all statements regarding the ceramic spring module.

[0013] According to claim 6, the housing can be made of plastic, which also makes the housing electrically neutral. Particularly preferably, the plastic is glass-fiber reinforced to achieve high mechanical strength, in particular to withstand high compressive loads from the ceramic springs. This also ensures high dimensional stability. The housing should also withstand the ambient conditions in the active part of the transformer, in particular when surrounded by insulating and cooling fluid. In addition, the glass-fiber reinforced plastic preferably has high electrical strength. The housing can also be approximately the size of a chipboard or resin-compressed wood block for a transformer.

[0014] Ceramic springs are susceptible to tensile loads, which, depending on the application, either do not occur or can be eliminated by the housing of the ceramic spring module, and to excessive spring travel. According to claim 7, a limit stop is therefore proposed that defines and thus limits the maximum compression, i.e., the maximum compressive load, of the springs. The stop can define the maximum adjustability of two housing parts relative to each other.

[0015] Claim 8 specifies preferred maximum and minimum spring travels. These relate to the maximum adjustment of the two housing parts relative to each other and thus sum up the spring travels of some of the ceramic springs, if several are present.

[0016] In applications where an insulating medium is used, the ceramic spring module can be used in the insulating medium, like the pressboard blocks before it. For this purpose, the ceramic spring module according to claim 9 preferably has at least one opening for hydraulic pressure equalization.

[0017] The double-sided spring action of the ceramic springs is generally undesirable during transformer operation. The desired effect of the disc spring is to apply permanent axial pressure to compress the high-voltage assembly. This means that if the high-voltage assembly loses length, the reduction in length is compensated for by the ceramic spring. If the high-voltage assembly expands in length, as occurs in the event of a short circuit during operation, this is prevented by arranging the ceramic disc springs in a closed area within the housing, which is preferably provided with small-diameter holes.

[0018] The principle is based on the inertia of liquids, utilizing the incompressible volume stability of the insulating medium. During operation, the insulating medium is located in the spaces between the disc springs. When counterpressure occurs in the millisecond range, the disc spring assembly acts like a solid column, since the insulating medium cannot escape quickly enough through the small-diameter openings. This prevents unwanted axial expansion of the high-voltage assembly.

[0019] Until now, the remaining preload during operation was usually not measurable, meaning that transformer failure was unexpected. Thanks to the new operating principle using springs, it is now possible to measure the preload during operation. For this purpose, according to claim 10, it is proposed that the ceramic spring module have a sensor arrangement for measuring the spring deflection of the ceramic spring module. This measurement can be carried out, in particular, using an optical sensor in which the sensor head and the sensor evaluation unit are separate from one another. Using a fiber optic cable and, for example, an optical laser measurement, the electronics can be placed outside the ceramic spring module and also outside the high-voltage assembly. This enables predictive maintenance of the transformer, which can prevent significant damage and save costs.

[0020] According to a further teaching according to claim 11, which also has independent significance, a high-voltage assembly in which a proposed ceramic spring is used is claimed, wherein preferably the ceramic spring is used in a proposed ceramic spring module.

[0021] Reference may be made to all statements regarding the proposed use and the proposed ceramic spring module. Reference may also be made to all statements regarding the high-voltage assembly regarding the use and the ceramic spring module.

[0022] Claim 12 specifies a preferred embodiment of the high-voltage assembly as a transformer and explains how the ceramic spring modules are preferably used in this case.

[0023] For this purpose, the ceramic spring modules according to claim 13 can preferably be immersed in insulating medium and / or the sensor evaluation unit can be arranged outside the housing and / or outside the insulating medium, so that it has to withstand in particular less electric field and less adverse environmental conditions.

[0024] According to a further teaching according to claim 14, which also has independent significance, a method for producing a high-voltage assembly is claimed.

[0025] It is essential that a coil and a frame are present, that the coil is pre-tensioned, that a suggested ceramic spring module is placed between the coil and the frame, and that the lock of the ceramic spring module is released.

[0026] Reference may be made to all statements regarding the proposed use, the proposed ceramic spring module, and the proposed high-voltage assembly. Reference may also be made to all statements regarding the method for manufacturing a high-voltage assembly regarding the use, the ceramic spring module, and the high-voltage assembly.

[0027] According to claim 15, the ceramic spring is preferably manufactured by pressing a green compact, which is then sintered and ground. In particular, grinding results in a smoother surface, resulting in fewer tolerances in the force distribution on the ceramic spring.

[0028] In the following, the invention is explained in more detail with reference to a drawing which merely represents exemplary embodiments. In the drawing, Fig. 1 a high-voltage assembly and a ceramic spring module, Fig. 2 a view into the ceramic spring module and a disc spring column and its individual parts, Fig. 3 a plan view of and a section through the ceramic spring module and Fig. 4 an enlargement of a section of the ceramic spring module in two states, which illustrate the operating principle of the sensor arrangement

[0029] The exemplary embodiment illustrated in the figures and thus preferred relates to the use of a ceramic spring 1 for preloading a component of a high-voltage assembly 2. Here and preferably, the high-voltage assembly 2 is a transformer 3. Fig. 1a) shows part of such a transformer 3. A frame 4 can be seen and, arranged within this frame 4, three transformer assemblies 5, each having two coils 6 for converting a voltage from one voltage level to another. These coils 6 are clamped in the frame 4 by means of a ceramic spring 1 in a manner to be explained below, so that the windings of the coils 6 are pressed against one another and, during transport and / or due to a mains frequency, for example 50 Hz, do not move relative to one another, which could damage the insulation of the windings. Not shown are other components of the transformer 3, such as a transformer housing, busbars, and the like. However, it is known that, for example, the busbars can be arranged on the frame 4.Both the coils 6 themselves and the busbars generate a strong electric field that makes the use of metallic components difficult or even impossible.

[0030] The ceramic spring 1 is arranged in an electric field of a high voltage of the high-voltage module 2. The electric field can be illustrated using the example of the transformer 3 in Fig. 1a) by the coils 6, but also by the busbars (not shown). High voltage is defined here, as is often the case, as a voltage of at least 1 kV alternating current or at least 1.5 kV direct current. The distance between the ceramic spring 1 and the high-voltage component 7 is here and preferably at most one meter, more preferably at most 75 cm, even more preferably at most 50 cm. Here and preferably, the high-voltage component 7 has a rated power or rated apparent power of at least 1 MVA.

[0031] Here, and preferably, the ceramic spring 1 prestresses a high-voltage component 7 of the high-voltage assembly 2. The prestressed high-voltage component 7 does not have to be the same component in whose electric field the ceramic spring 1 is arranged. However, this is preferably the case. Using the example of the transformer 3, for example, the busbars would typically be arranged closer to the ceramic spring 1 than the windings of the coils 6. However, this is usually not important; a steel spring cannot be used there either way.

[0032] Ceramic springs 1 that can be used here are known, for example, from DE 20 2007 017 290 U1. Here and preferably, the ceramic comprises or consists of a, in particular partially stabilized, zirconium dioxide and / or silicon nitride and / or aluminum oxide and / or alumina toughened zirconia (ATZ) and / or zirconia toughened alumina. The zirconium dioxide can be a ductile zirconium dioxide and / or zirconium dioxide partially stabilized with yttrium oxide and / or magnesium oxide. Here and preferably, the ceramic spring 1 has a modulus of elasticity of at least 50 GPa to at most 400 Gpa, preferably of at least 150 Gpa to at most 300 Gpa, even more preferably of 180 Gpa to 240 Gpa. The ceramic is thus comparable to steel. Here and preferably, the ceramic spring 1 has a maximum spring force of at least 1000 N, preferably at least 1500 N, more preferably at least 2000 N.

[0033] Here, and preferably, it is provided that the high-voltage assembly 2 is a transformer 3, in particular with a rated apparent power of at least 30 MVA, preferably at least 100 MVA, and / or that the high voltage is at least 30 kV, preferably at least 100 kV, and is preferably applied to the prestressed component 8, and / or that the high-voltage-carrying component 7 is a prestressed coil 6, in particular a transformer coil, preferably that a winding pressure of the coil 6 is at least 1 kN, preferably at least 10 kN. The specification of the winding pressure refers to the time immediately after the end of production.

[0034] Fig. 1b) shows a ceramic spring module 9, which here and preferably has several ceramic springs 1. This will be explained in more detail below. Fig. 2a) shows the ceramic spring module 9 with a cut-out corner, so that it can be seen that several ceramic springs 1 are arranged in this ceramic spring module 9.

[0035] Here and preferably and as in Fig. 2, the ceramic spring 1 is a ceramic disc spring 10. Here and preferably, the ceramic disc spring 10 is part of a disc spring package 11 made of ceramic disc springs 10, in particular one which is connected alternately.

[0036] Fig. Figure 2 shows such a disc spring assembly 11 in a), b), and c). Here, and preferably, the disc spring assembly 11 is a disc spring column 12. It can be provided that the ceramic disc spring 10 has a diameter of at least 30 mm, preferably at least 40 mm, more preferably at least 50 mm, and / or at most 70 mm, preferably at most 60 mm, more preferably at most 50 mm. The ceramic disc spring 10 preferably has an opening 13, which can be arranged centrally. The opening 13 can, for example, have a diameter of 25 mm. Fig. 2d) shows two ceramic disc springs 10 arranged alternately to each other and spaced apart for better illustration. Fig. 2b), there designed as a disc spring column 12, preferably has the Fig. 2c). The ceramic disc springs 10 are preferably interconnected alternately, resulting in a greater spring travel 14. Together, they generate the spring force of the disc spring assembly 11.

[0037] Here, and preferably, the disc spring stack 12 has a base 15 and a cover 16, between which the spring force of the ceramic disc springs 10 acts. The ceramic disc springs 10 can be mounted with the opening 13 on a support 17 of the disc spring stack 12. The support 17 can be supported on the base 15, in this case by resting thereon. The cover 16 here and preferably has an opening 13, through which the cover 16 is also mounted on the support 17. Thus, the cover 16 is adjustable relative to the base 15. Here, and preferably, the support 17 is cylindrical.

[0038] Fig. 3 shows a top view and a cross section of the ceramic spring module 9. In Fig. 3 it can be seen that here and preferably six disc spring columns 12 are combined in a ceramic spring module 9.

[0039] With regard to the high-voltage assembly 2, one embodiment provides for the coil 6 to be preloaded by means of at least one, preferably at least two, more preferably at least six, disc spring assemblies 11 or disc spring assemblies 11. Preferably, at least two disc spring assemblies are part of a ceramic spring module 9. In the ceramic spring module 9, the disc spring assemblies 11 are connected in parallel and together generate a spring force of the ceramic spring module 9.

[0040] A disc spring column 12 preferably has a height 18 along the direction of the spring force of at most 15 cm, preferably at most 10 cm. The ceramic disc springs 10 account for approximately 5 cm of this height 18 in this case, and preferably in the relaxed state. The disc spring column 12 can have a maximum diameter of approximately 6 cm.

[0041] According to a further teaching, a ceramic spring module 9 is proposed for prestressing a component of a high-voltage assembly 2 and for use in a high-voltage electric field. The ceramic spring module 9 has, as shown by way of example in the figures, a multi-part housing 19. At least one ceramic spring 1 is arranged in the housing 19.

[0042] The housing 19 has a first housing part 20 and a second housing part 21 that is adjustable relative to the first housing part 20. For example, the first housing part 20 is shown at the bottom and is designed as a trough. The second housing part 21 can be adjusted relative to the first housing part 20 here, preferably along the direction of the spring force of the ceramic spring 1. The second housing part 21 is shown at the top. The second housing part 21 preferably protrudes into the first housing part 20 here.

[0043] The first housing part 20 and the second housing part 21 are from a zero position 22 ( Fig. 4 a)) against a spring force of the ceramic spring 1 against each other into a compression position 23 ( Fig. 4b)). In the compression position 23, the ceramic spring 1 is subjected to compression. The ceramic spring module 9 is designed here, and preferably, to be individually handled.

[0044] Here and preferably, the first housing part 20 and the second housing part 21 are secured by a releasable securing device 24 in the compression position 23. This releasable securing device 24 is in Fig. 1 shown.

[0045] The releasable locking device 24 prevents the ceramic spring 1 or the ceramic springs 1 from relaxing when the ceramic spring module 9 is not clamped. This makes it possible to transport and assemble the ceramic spring module 9 in a pre-tensioned state without the need for a device to tension the ceramic spring module 9. The releasable locking device can comprise one or more tensioning straps. For this purpose, a groove is preferably milled into the housing 19 so that the tensioning strap can be released when installed. The releasable locking device 24 can alternatively be designed as a rod that can be inserted through the ceramic spring module 9. Fig. 1b) shows how the removable fuse 24 is released. The ceramic spring module 9 can thus be used in the manufacture of a transformer 3 like a pressboard block, and only generates its spring force upon release of the fuse 24. Here, and preferably, at least 20 ceramic disc springs 10, preferably at least 80 ceramic disc springs 10, and / or a maximum of 200 ceramic disc springs 10 are provided per ceramic spring module 9. Here, 6x18, i.e., 108 ceramic disc springs 10, are provided.

[0046] Reference may be made to all statements concerning the proposed use.

[0047] Furthermore, it is preferably provided here that the housing 19 comprises a plastic, in particular consists of plastic, preferably that the plastic is a glass fiber reinforced plastic.

[0048] The ceramic spring module 9 can have a height 18 of 5 cm to 30 cm, preferably 10 cm to 20 cm, with the spring force of the ceramic spring 1 acting along the height 18. The ceramic spring module 9 preferably has a width 25 of 10 cm to 40 cm, preferably 15 cm to 30 cm, and a length 26 of 10 cm to 50 cm, preferably 20 cm to 40 cm. The height refers to the relaxed state. Other housing shapes, for example, a cylindrical housing, are also preferred.

[0049] To prevent the ceramic disc springs 10 from being overloaded and potentially breaking, the ceramic spring module 9 can be provided with a limit stop that defines a maximum compression of the springs. Preferably, the limit stop is formed by the first housing part 20. Further preferably, the second housing part 21 abuts the stop 27.

[0050] Attack 27 is in Fig. 3 and Fig. 4, where in Fig. 4 shows the maximum compressed state on the right, in which the second housing part 21 abuts the second housing part 21. Alternatively, the stop 27 can also be a component of the disc spring assembly 11 and / or one or more of the ceramic springs 1. In particular, the stop 27 could be provided on the cover 16 of the disc spring column 12, which could abut the carrier 17 to limit the spring travel 14. For this purpose, the opening 13 of the cover 16 could be designed as a blind hole.

[0051] Here and preferably, a maximum spring travel 14 of the ceramic spring module 9 from the zero position 22 to a maximum compression position 23 is at most 50 mm, preferably at most 40 mm, more preferably at most 30 mm, and / or at least 10 mm, preferably at least 20 mm, more preferably at least 30 mm. The maximum spring force that can be generated by the ceramic spring module 9 is here and preferably greater than 100 kN, preferably greater than 150 kN, more preferably greater than 200 kN. In use, the ceramic spring module 9 preferably generates a spring force greater than 50 kN.

[0052] Furthermore, it is preferably provided here that the ceramic spring module 9 has at least one compensation opening 28 for hydraulic pressure equalization. The compensation opening 28 can have a bore and / or a groove, as shown in the figures. Here, preferably, several compensation openings 28 are provided, each having a bore and a groove. The grooves are provided here because the bores could otherwise be completely covered.

[0053] This configuration takes into account the fact that the ceramic spring module 9 is used here and preferably in an insulating medium, in particular a transformer oil or a natural or synthetic ester. The housing 19 is therefore preferably designed such that the ceramic spring 1 or the ceramic springs 1 are arranged in the insulating medium when the housing 19 is arranged in the insulating medium.

[0054] As in the Fig. 3 and Fig. 4, it is shown here and preferably such that the ceramic spring module 9 has a sensor arrangement 29 for measuring the spring travel 14 of the ceramic spring module 9. Using this sensor arrangement 29, a remaining preload of the ceramic spring module 9 can be determined. A failure of the high-voltage assembly 2 can thus be better predicted or prevented.

[0055] Preferably, the sensor arrangement 29 comprises a sensor 30 with a sensor head 31, which is arranged in the housing 19 of the ceramic spring module 9, and a sensor evaluation unit 32, which is arranged outside the housing 19 of the ceramic spring module 9.

[0056] Further preferably, the sensor head 31 and the sensor evaluation unit 32 are connected by means of a fiber optic cable 33 and the sensor 30 is an optical sensor 30. Other fiber optic cables would also be conceivable.

[0057] The optical sensor 30 may be a laser sensor. Preferred measurement methods are based on a time-of-flight measurement, Rayleigh scattering, or a phase shift. The measurement principle is best illustrated in Fig. 4, where, for example, a laser beam emerges from one end of the fiber optic cable 33 and strikes the adjustable second housing part 21. In comparison between the left and right illustration in Fig. Figure 4 shows that the path of the laser beam depends on the spring travel 14. In the right-hand illustration, the ceramic springs 1 exert a greater spring force than in the left-hand illustration. Other measurement principles and sensors are also conceivable.

[0058] According to a further teaching, a high-voltage assembly 2 is proposed, in which a ceramic spring 1 is used as proposed. Preferably, the ceramic spring 1 is used in a proposed ceramic spring module 9.

[0059] Reference may be made to all statements regarding the proposed use and the proposed ceramic spring module 9.

[0060] Furthermore, it is preferably provided that the high-voltage assembly 2 is a transformer 3 and that the high-voltage assembly 2 has a plurality of ceramic spring modules 9. Preferably and in Fig. As shown in Figure 1, the high-voltage module 2 comprises several transformer assemblies 5, each of which has a pair of coils for voltage conversion, in particular for one phase each. Accordingly, three transformer assemblies 5 for three phases are shown here.

[0061] It is also apparent and preferred that the transformer assemblies 5 are each individually prestressed. The high-voltage assembly 2 can have a frame 4 in which the transformer assemblies 5 are arranged. Preferably, the ceramic spring modules 9 for prestressing the transformer assemblies 5 are supported on the frame 4. Thus, several transformer assemblies 5 are prestressed against a frame 4.

[0062] Furthermore, it is preferably provided here that the ceramic spring module 9, preferably the ceramic spring modules 9, is or are immersed in an insulating medium, in particular transformer oil, and / or that the sensor evaluation unit 32 is arranged outside a transformer housing and / or outside the insulating medium.

[0063] According to a further teaching, a method for producing a high-voltage assembly 2 with at least one prestressed coil 6 is proposed, in particular wherein the high-voltage assembly 2 is a transformer 3.

[0064] According to this further teaching, it is essential that a coil 6 and a frame 4 are present, that the coil 6 is preloaded, that a proposed ceramic spring module 9 is placed between the coil 6 and the frame 4, and that the securing device 24 of the ceramic spring module 9 is released. Preferably, several ceramic spring modules 9 are placed between the coils 6 and the frame 4. Pressboards can be provided between the coils 6 and the ceramic spring modules 9.

[0065] Reference may be made to all statements regarding the proposed use, the proposed ceramic spring module 9 and the proposed high-voltage assembly 2.

[0066] Furthermore, it is preferably provided here that the ceramic spring 1 of the ceramic spring module 9 is manufactured by pressing a green compact, sintering the green compact, and grinding the green compact. In particular, the manufacturing is provided in this order. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 20 2007 017 290 U1

[0032]

Claims

[1] Use of a ceramic spring (1) for prestressing a component of a high-voltage assembly (2), wherein the ceramic spring (1) is arranged in an electrical field of a high voltage of the high-voltage assembly (2), in particular prestressing a high-voltage-carrying component (7) of the high-voltage assembly (2). [2] Use according to claim 1, characterized by that the high-voltage assembly (2) is a transformer (3), in particular with a rated apparent power of at least 30 MVA, preferably at least 100 MVA, and / or that the high voltage is at least 30 kV, preferably at least 100 kV, and is preferably applied to the prestressed component (8), and / or that the high-voltage-carrying component (7) is a prestressed coil (6), in particular a transformer coil, preferably that a winding pressure of the coil (6) is at least 1 kN, preferably at least 10 kN. [3] Use according to claim 1 or 2, characterized by that the ceramic spring (1) is a ceramic disc spring (10), preferably that the ceramic disc spring (10) is part of a disc spring assembly (11), in particular an alternately connected one, made of ceramic disc springs (10), further preferably that the disc spring assembly (11) is a disc spring column (12). [4] Use according to claims 2 and 3, characterized by that the coil (6) is prestressed by means of at least one, preferably at least 2, more preferably at least 6, disc spring assemblies (11) or disc spring assemblies (11), preferably that at least two disc spring assemblies are part of a ceramic spring module (9), that in the ceramic spring module (9) the disc spring assemblies (11) are connected in parallel and together form a spring force of the ceramic spring module (9). [5] Ceramic spring module for prestressing a component of a high-voltage assembly (2) and for use in an electric field of a high voltage, wherein the ceramic spring module (9) has a multi-part housing (19), wherein at least one ceramic spring (1) is arranged in the housing (19), wherein the housing (19) has a first housing part (20) and a second housing part (21) which is adjustable relative to the first housing part (20), wherein the first housing part (20) and the second housing part (21) are adjustable from a zero position (22) against a spring force of the ceramic spring (1) against each other into a compression position (23) in which the ceramic spring (1) is subjected to pressure, wherein the ceramic spring module (9) is designed to be individually handled, preferably, wherein the first housing part (20) and the second housing part (21) are secured in the compression position (23) by a releasable securing device (24). [6] Ceramic spring module according to claim 5, characterized by that the housing (19) comprises a plastic, in particular consists of plastic, preferably that the plastic is a glass fiber reinforced plastic, and / or that the ceramic spring module (9) has a height (18) of 5 cm to 30 cm, preferably 10 cm to 20 cm, that the spring force of the ceramic spring (1) acts along the height (18), preferably that the ceramic spring module (9) has a width (25) of 10 cm to 40 cm, preferably 15 cm to 30 cm, a length (26) of 10 cm to 50 cm, preferably 20 cm to 40 cm. [7] Ceramic spring module according to claim 5 or 6, characterized by that the ceramic spring module (9) has a limit stop which defines a maximum compression of the springs, preferably that the limit stop is formed by the first housing part (20), further preferably that the second housing part (21) abuts the stop (27). [8] Ceramic spring module according to one of claims 5 to 7, characterized by that a maximum spring travel (14) of the ceramic spring module (9) from the zero position (22) into a maximum compression position (23) is at most 50 mm, preferably at most 40 mm, more preferably at most 30 mm, and / or at least 10 mm, preferably at least 20 mm, more preferably at least 30 mm. [9] Ceramic spring module according to one of claims 5 to 8, characterized by that the ceramic spring module (9) has at least one compensation opening (28) for hydraulic pressure compensation. [10] Ceramic spring module according to one of claims 5 to 9, characterized bythat the ceramic spring module (9) has a sensor arrangement (29) for measuring the spring travel (14) of the ceramic spring module (9), preferably that the sensor arrangement (29) has a sensor (30) with a sensor head (31) which is arranged in the housing (19) of the ceramic spring module (9) and with a sensor evaluation unit (32) which is arranged outside the housing (19) of the ceramic spring module (9), further preferably that the sensor head (31) and the sensor evaluation unit (32) are connected by means of a fiber optic cable (33) and the sensor (30) is an optical sensor (30). [11] High-voltage assembly in which a ceramic spring (1) is used according to one of claims 1 to 4, preferably that the ceramic spring (1) is used in a ceramic spring module (9) according to one of claims 5 to 10. [12] High-voltage assembly according to claim 11, characterized bythat the high-voltage assembly (2) is a transformer (3), that the high-voltage assembly (2) has a plurality of ceramic spring modules (9), preferably that the high-voltage assembly (2) has a plurality of transformer assemblies (5), each having a pair of coils for voltage conversion, in particular for one phase each, that the transformer assemblies (5) are each individually prestressed, further preferably that the high-voltage assembly (2) has a frame (4) in which the transformer assemblies (5) are arranged and that ceramic spring modules (9) for prestressing the transformer assemblies (5) are supported on the frame (4). [13] High-voltage assembly according to claim 11 or 12, characterized by that the ceramic spring module (9), preferably the ceramic spring modules (9), is or are immersed in insulating medium, and / or that the sensor evaluation unit (32) is arranged outside a transformer housing and / or outside the insulating medium. [14] Method for producing a high-voltage assembly (2) with at least one prestressed coil (6), in particular wherein the high-voltage assembly (2) is a transformer (3), characterized by that a coil (6) and a frame (4) are present, that the coil (6) is prestressed, that a ceramic spring module (9) according to one of claims 5 to 10 is placed between the coil (6) and the frame (4), that the securing means (24) of the ceramic spring module (9) is released. [15] Method according to claim 14, characterized by that the ceramic spring (1) of the ceramic spring module (9) is produced by pressing a green compact, sintering the green compact and grinding the green compact.

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