EP1995739B1 - HV isolator and cooling element for this HV isolator - Google Patents

Abstract

The insulator has an insulating tube (1) with ends, which are designed as a carrier ring (10). A glued joint (51) is provided between an adhesive bonding surface of the ring and an adhesive bonding surface of a metal armature. A hollow space (15) extends along an axis of the tube, where the hollow space is surrounded by the tube and the armature. An adhesive channel (50) is arranged between the hollow space and the glued joint, where the channel is locked with the adhesive and exhibits cross section, which is sufficient to guide the adhesive from the hollow space into the joint. Independent claims are also included for the following: (1) a method for producing insulator (2) a device for implementing the method for producing an insulator.

Description

The present invention relates to a high voltage insulator according to the preamble of claim 1, a method of manufacturing this insulator, an apparatus for carrying out the method and a cooling element with this high voltage insulator. The high-voltage insulator comprises in coaxial arrangement at least one insulating tube with an end formed as a support ring, a support ring held on the hollow metal fitting, an adhesive joint, which is provided between an adhesive surface of the support ring and an adhesive surface of the metal fitting and filled with a set adhesive layer vacuum-tight, and along The axis of the insulating tube extending cavity which is radially bounded by the insulating tube and the metal fitting. In general, in this high-voltage insulator, the other end facing away from the support ring of the insulating tube is also formed as a support ring and connected via an adhesive joint with another metal fitting.

Such an insulator can be used as an insulating section in a passive cooling of a high-current high-voltage device, with high voltage basically an operating voltage greater than 1 kV to understand. However, the preferred voltage range is below 100 kV and mainly relates to high-current devices and systems with nominal voltages of typically 10 to 50 kV.

The current carrying capacity of such apparatus and equipment is thermally limited. For nominal currents in the range of typically 10 to 50 kA, as they are performed as in designed as a generator switch high current devices, therefore, particularly active cooling elements (eg air-air heat exchanger with fans) or passive cooling elements with particularly good efficiency used, in particular heat pipes (heat pipes), which also contain an evaporator and a heat exchanger and a working medium in addition to the high-voltage insulator defined above. Heat generated in the high-current device due to current losses is used to evaporate the working fluid. The vaporized working fluid is transported to an externally arranged heat exchanger and there by condensation from the loss heat formed in the high-current device again.

As a generator switch running high-current devices are generally carried out single-phase encapsulated and have a disposed in the enclosure and located at high voltage potential inner conductor. Heat generated by current losses on the inner conductor is dissipated through the enclosure to the ambient air. This means that there must be an electrically insulating path between a high-voltage potential evaporator and a heat pipe condenser held at ground potential, which must be designed according to the required high voltage (e.g., 150 kV BIL). Evaporator and heat exchanger (condenser) are held vacuum-tight at the two ends of the high-voltage insulator.

Since in such a high-performance, passive cooling element moving parts, such as fans or blowers omitted, can with this cooling element, the heat loss cheap and efficiently removed from the enclosure. Furthermore, such a cooling element is maintenance-free. The high-voltage insulator fulfills several functions, especially those of the guide of the working fluid and the separation of the potentials of evaporator and condenser. The reliability of such a powerful passive cooling element and equipped with such a cooling element high-voltage system is only guaranteed if the insulator performs the above functions over many years. Such an insulator should therefore be maintenance-free over a long period, typically 20 years. Such a high long-term stability requires an extremely low leak rate, as this is the only way to avoid a loss of work equipment.

STATE OF THE ART

A high voltage insulator of the aforementioned type is described in WO 2006/053452 A1 , This insulator is part of a heat pipe designed as a hollow cooling element, which serves to dissipate heat from a generator lead. He has in coaxial arrangement a mechanically supporting insulating tube made of a fiber-reinforced polymer and from coaxially held diffusion barriers and two hollow metal fittings, which are bonded vacuum-tight with the two, each designed as a support ring ends of the insulating tube. Between an adhesive surface of each of the two support rings and an adhesive surface of each of the two metal fittings extending from the front side of each support ring on its lateral surface adhesive joint is provided, which is filled vacuum-tight with a set adhesive layer.

On one of the two metal fittings a held at the potential of a high-voltage conductor evaporator is attached to the other fitting held at the potential of a grounded enclosure capacitor. The high-voltage insulator forms an insulating section of a cooling element which transmits heat formed by current losses in the high-voltage conductor to the encapsulation. Here, a working medium contained in the interior of the cooling element, such as in particular acetone or a hydro-fluoro ether, the heat transfer and circulates as vapor from the evaporator through the insulating tube to the condenser, in which the vapor condenses while releasing the heat as a liquid. The liquid is returned to the evaporator through the high voltage insulator. The high-voltage insulator therefore serves not only as an insulating section, but also as a conduit for the working fluid. Since this line receives a chemical medium, a continuous temperature of typically 80 ° C is exposed and must be liquid, gas and vacuum tight over many, typically 20 years, are applied to the adhesive joints between each formed as a support ring both ends of the insulating tube and high demands placed on metal fittings.

PRESENTATION OF THE INVENTION

The invention, as indicated in the claims, the object is to provide a high-voltage insulator of the type mentioned, which has a low leakage rate and even after many years of operation under strong mechanical, electrical, thermal and chemical stress by a high reliability characterized and to provide a method for producing this high voltage insulator, an apparatus for performing this method and a cooling element containing this insulator.

In the case of the high-voltage insulator according to the invention, at least one predominantly radially-guided adhesive channel is arranged between the cavity and the adhesive joint, which is closed with set adhesive and which has a cross-section which is sufficient to guide adhesive, which has not set before the bonded adhesive layer forms, from the cavity into the adhesive joint. Since, before setting, the adhesive is guided out of the hollow space via the adhesive channel into the glued joint, a particularly homogeneous adhesive layer kept free of undesired air inclusions between two parts to be joined, i.e. in a comparatively short time, can be produced. between a support ring of an insulating tube and a metal fitting, can be achieved. Since the adhesive surfaces of the two joining parts covered to 100% with set adhesive and the entire bond line is completely filled with set adhesive, characterized the high voltage insulator according to the invention and a high voltage insulator containing this cooling element by a very low leakage rate and excellent dielectric behavior, in particular a high creep resistance, out. High voltage insulator and cooling element according to the invention accordingly have a high long-term stability.

In a particularly suitable for the preparation of the high voltage insulator method, the insulating tube and the metal fitting are grouted to form the joint and the cavity, a liquid adhesive injection aid is installed in the cavity, and the liquid adhesive with the injection aid in a compression space designed as a portion of the cavity pressurized and injected from the compression chamber via the at least one adhesive channel in the glued joint. In this Method, the adhesive is introduced free of air bubbles and well distributed in the glued joint and is achieved in a safe and easy to reproduce a vacuum-tight adhesive bond. Vacuum-tight high-voltage insulators with a low leakage rate and a long service life can thus be produced virtually without waste.

In a device advantageous for carrying out this method, the injection aid is designed as a piston-cylinder compression device and has a suitable for receiving the liquid adhesive formed compression space radially outwardly from the support ring and axially fixed in the metal fitting cylinder base and a support ring axially displaceable piston is limited. The piston-cylinder compression device can be easily incorporated into the manufacturing process, ensuring that unwanted air is expelled from the bondline and the bondline is completely filled with bubble-free adhesive.

Further features and further advantageous effects of the invention will become apparent from the embodiment described below.

BRIEF DESCRIPTION OF THE FIGURES

Fig. 1

eine Seitenansicht einer Vorrichtung, in der gerade ein Hochspannungsisolator nach der Erfindung hergestellt wird,

Fig. 2

in perspektivischer Darstellung ein Isolierrohr des Hochspannungsisolators gemäss Fig.1,

Fig. 3

in vergrösserter Darstellung einen als Tragring ausgeführten Endabschnitt III des Isolierrohrs nach Fig.2,

Fig. 4

eine Aufsicht eine längs einer Achse A geführten Schnitt durch den unteren Endabschnitt des Hochspannungsisolators nach Fig.1 beim Einspritzen von Klebstoff in eine zwischen einem Tragring eines Isolierrohrs des Hochspannungsisolators und einer Metallarmatur angeordneten Klebfuge,

Fig. 5

die Aufsicht gemäss Fig.4 nach dem Einspritzen des Klebstoffs, und

Fig. 6

die Aufsicht gemäss Fig.4 nach dem Entfernen eines als Injektionshilfe ausgeführten Teils der Vorrichtung zur Herstellung des Hochspannungsisolators.

With reference to drawings, this embodiment of the invention will be explained in more detail. Hereby shows:

Fig. 1

a side view of an apparatus in which a high voltage insulator is made according to the invention,

Fig. 2

in perspective view of an insulating tube of the high voltage insulator according to Fig.1 .

Fig. 3

in an enlarged view of an executed as a support ring end portion III of the insulating pipe after Fig.2 .

Fig. 4

a plan view along an axis A guided section through the lower end portion of the high-voltage insulator after Fig.1 when injecting Adhesive in an adhesive joint arranged between a support ring of an insulating tube of the high-voltage insulator and a metal fitting,

Fig. 5

the supervision according to Figure 4 after injecting the adhesive, and

Fig. 6

the supervision according to Figure 4 after removing a part of the device for producing the high-voltage insulator designed as an injection aid.

WAY FOR CARRYING OUT THE INVENTION

In all figures, like reference numerals refer to like-acting parts. On off Fig.1 apparent, axially symmetrical trained high-voltage insulator H is arranged along its axis of symmetry A aligned in a clamping device 3 of a device V for its preparation. The high-voltage insulator includes an insulating tube 1, whose two ends are each formed as a support ring 10, 10 ', and two hollow metal fittings 2 and 2'. The insulating tube 1 is made of a polymeric composite, for example, based on a duromer, such as an epoxide, and a filler, such as quartz powder or glass fibers, but may also be made of a ceramic, such as porcelain. In a coaxial arrangement, the metal fitting 2 is bonded to the support ring 10 and the metal fitting 2 'with the support ring 10' vacuum-tight. The tensioning device 3 is supported with a horizontally oriented base plate 30 on spacer feet 31 and has two vertically oriented threaded rods 32 which are rigidly secured to the base plate 30. In the base plate, a non-apparent opening is provided through which the lower part of the metal fitting 2 is guided. A formed as a field electrode 20 part of the metal fitting 2 rests on the base plate 30. The metal fitting 2 'has the same design as the metal fitting 2 and includes a field electrode 20', on which a pressure bar 33 rests. A part of the fitting 2 'corresponding to the lower part of the fitting 2 is guided through the pressure beam 33 by an opening, likewise not visible. The pressure bar 33 is by means of two guided on the threaded rods 32 pressure nuts 34 against the Field electrode 20 'pressed and thus sets the high-voltage insulator H in the clamping device 3.

The two support rings 10, 10 'are identical and have - in the FIGS. 2 and 3 shown in the support ring 10 - distance cam 11, which are formed in the free end face 12 of the support ring 10 and axially aligned. Each two of the distance cams 11 define a predominantly radially guided adhesive channel 50 in the circumferential direction of the end face 12. As can be seen, the four distance cams 11 shown in the illustrated embodiment define four predominantly radially oriented adhesive channels 50 arranged uniformly distributed in the circumferential direction (relative to the axis A).

In the inside of the support ring 10, a cylindrical sealing surface 13 is formed. How out Fig. 6 it can be seen, this sealing surface encloses a radially limited from the support ring 10 and between the adhesive channels 50 and a stop 14 axially extending portion of a cavity 15, respectively of the insulator H. the insulating tube 1 and the two metal fittings 2, 2 'is enclosed.

In the outside of the support ring 10 is one of the FIGS. 2 and 3 apparent adhesive surface 16 formed. As in Figure 6 is shown between this adhesive surface and an adhesive surface 21 of the metal fitting 2, an adhesive joint 51 is provided, which is filled vacuum-tight with a set adhesive layer. The adhesive channels 50, which extend between the cavity 15 and the adhesive joint 51, are sealed vacuum-tight with set adhesive. The adhesive joint 51 is connected to a plurality of circumferentially uniformly distributed, above the adhesive surface 21 mainly radially outwardly through the metal fitting 2 out vent openings 52. The bond line 51 is dimensioned so that its cross section between the adhesive channels 50 and the vent openings 52 decreases. An adhesive gap 51 sized in this way can be produced in an advantageous manner by tapering the adhesive surface 16. The conical adhesive surface 16 expands in the axial direction between the adhesive channels 50 and the ventilation openings 52 and can in the manufacture of the insulating tube 1, such as during the casting of the insulating tube and / or by machining a precursor body of the insulating tube, are easily formed in the support ring 10.

To manufacture the high-voltage insulator H, the insulating tube 1 and the metal fitting 2 are grouted to form the joint 51. In order to achieve a good interference fit, the metal fitting 2 is heated, typically to about 150 ° C, and the heated metal fitting 2 mounted on the support ring 10 until the distance cam 11 sit on a radially inwardly guided shoulder 22 of the metal fitting 2 ( FIGS. 4 to 6 ). Similarly, the metal fitting 2 'and the support ring 2' are grouted, although these two parts can also be connected by screwing using sealing rings or by molding. In any case, such an axially extending, of the insulating tube 1 and the two hollow metal fittings 2, 2 'axially limited cavity 15 is formed.

Like from the FIGS. 4 and 5 can be seen, in the cavity 15, a liquid adhesive 40 containing injection aid 4 is installed. This injection aid is designed as a piston-cylinder compression device and comprises a liquid (not set) adhesive 40 receiving compression chamber 41 ( Figure 4 ), which is bounded radially outward by the support ring 10 and the shoulder 22 of the metal fitting 2 and axially by a fixed in the metal fitting 10 cylinder bottom 42 and a support ring 10 axially displaceable piston 43. Cylinder bottom 42 and piston 43 carry on their lateral surfaces in each case at least one not shown for reasons of clarity sealing ring. The sealing ring carried by the cylinder base 42 is gas-tight on a cylindrically symmetrical inner surface of the metal fitting 2 in the region of the shoulder 22, whereas the sealing ring of the displaceable between the stop 14 and the cylinder base 42 in the axial direction piston 43 is stored gasund liquid-tight on the sealing surface 13.

In the installation of the injection aid 3 insulating tube 1 and metal fittings 2, 2 'are initially held so that the metal fitting 2 faces upward. The piston 43 is now brought through the metal fitting 2 into the cavity 15 and held against the stop 14. It can be seen in one of the compression space 41 bounding side of the piston 43 is formed in the manner of a funnel formed conical recess 44 for receiving the liquid adhesive 40. A metered quantity of liquid adhesive, for example a two-component adhesive based on an epoxide, is already provided in this depression. From above, the cylinder bottom 42 is then inserted into the cavity 15. With one out FIGS. 1 . 4 and 5 apparent lock nut 45, the piston head 42 is secured against falling out. Then the whole arrangement is turned down and so on Figure 4 achieved apparent position of the arrangement in which the injection aid 4 has a compression space 41 which extends in the axial direction from the sealing surface 13 via inlets of the adhesive channels 50 to the inner surface of the metal fitting 2 in the region of the shoulder 22.

As in Fig.1 As shown, the assembly is secured in the tensioning device 3 and a plunger 46 is inserted through the metal fitting 2 'from above into the cavity 15. This plunger is supported on the side facing away from the compression space 41 side on the piston 43 ( Fig. 4 ). Now works, as in Figure 4 shown, on the plunger 46 an axially downward force K, the piston 43 is guided downward, thereby increasing the pressure of the liquid adhesive 40 in the compression space 41. A displacement of the metal fitting 2 under the action of the hydraulic force occurring through the tensioning device 3 prevents. The liquid adhesive 40 is injected via the adhesive channels 50 in the adhesive joint 51. The adhesive channels 50 are dimensioned such that a sufficient amount of unbonded adhesive 40 is guided from the compression space 41 into the adhesive joint 51 before the set adhesive layer is formed. The supplied adhesive 40 displaces the air in the adhesive joint 51 and fills the adhesive joint 51 up to the ventilation openings 52. Excess adhesive 40 enters the vent openings 52 to the outside. After removing the lock nut 45 then injection aid 4 and plunger 46 can be removed from the cavity 15 and the adhesive at elevated temperature, typically 60 to 80 ° C, cured. The leak rate of this splice is typically less 10- ⁹ [mbar I / s].

A particularly good distribution of the adhesive 40 in the adhesive joint 51 and thus a void-free, set adhesive layer is achieved in that the adhesive over a plurality of circumferentially uniformly distributed adhesive channels 50 is injected into the bond line 51. Due to the fact that the cross-section of the adhesive joint decreases in the direction of flow of the liquid adhesive 40, the liquid adhesive passes particularly uniformly and free of air bubbles out of the compression space into the adhesive joint 51. Therefore, a void-free set adhesive layer is achieved at the adhesion point. In addition, the thickness of this adhesive layer to the end face 12 of the support ring 10 increases towards. Unwanted voltage peaks at the end of the insulating tube 1 are so greatly reduced.

By vacuum-tight flanging of one with a liquid working fluid, preferably a hydro-fluoro ether, filled evaporator to one of the two metal fittings 2, 2 'and a capacitor to the other metal fitting a passive cooling element with negligible leakage rate and high long-term stability is achieved.

LIST OF REFERENCE NUMBERS

A

axis

H

High-voltage insulator

V

manufacturing device

K

force

1

insulating

2, 2 '

metal fittings

3

jig

4

injection Device

10, 10 '

metal fittings

11

spacer cams

12

front

13

sealing surface

14

attack

15

cavity

16

adhesive surface

20, 20 '

field electrodes

21

adhesive surface

22

paragraph

30

baseplate

31

Distance feet

32

threaded rods

33

pressure beam

34

forcing nuts

40

liquid adhesive

41

compression chamber

42

cylinder base

43

piston

44

deepening

45

locking nut

46

tappet

50

adhesive channels

51

bonded joint

52

vents

Claims (16)

1. High-voltage insulator (H), containing, in a coaxial arrangement:

   an insulating tube (1) with an end in the form of a bearing ring (10),

   a hollow metal armature (2) held on the bearing ring (10),

   an adhesive-bonding joint (51), which is provided between an adhesive-bonding area (16) of the bearing ring (10) and an adhesive-bonding area (21) of the metal armature (2) and is filled in a vacuum-tight manner with a cured adhesive layer,

   and

   a cavity (15), which is extended along the axis (A) of the insulating tube (1) and is radially delimited by the insulating tube (1) and the metal armature (2),

   characterized in that at least one predominantly radially guided adhesive channel (50) is arranged between the cavity (15) and the adhesive-bonding joint (51), which adhesive channel (50) is sealed with cured adhesive and has a cross section which is sufficient for guiding uncured adhesive (40) from the cavity (15) into the adhesive-bonding joint (51) prior to the formation of the cured adhesive layer.
2. Insulator according to Claim 1, characterized in that the at least one adhesive channel (50) is delimited in the circumferential direction by two axially aligned spacer cams (11).
3. Insulator according to Claim 2, characterized in that a plurality of spacer cams (11), which are arranged at a distance from one another in the circumferential direction and of which in each case two delimit one of a plurality of adhesive channels (50) in the circumferential direction, are provided.
4. Insulator according to either of Claims 2 and 3, characterized in that the spacer cams (11) are formed into an end side (12) of the bearing ring (10).
5. Insulator according to one of Claims 1 to 4, characterized in that a cylindrical sealing face (13) is formed into the bearing ring (10), which sealing face (13) surrounds a section of the cavity (15) which is delimited radially by the bearing ring (10) and is extended axially between the at least one adhesive channel (50) and a stop (14) of the insulating tube (1).
6. Insulator according to one of Claims 1 to 5, characterized in that the adhesive-bonding joint (51) is connected to at least one ventilation opening (52), which is guided predominantly radially on the outside.
7. Insulator according to Claim 6, characterized in that the cross section of the adhesive-bonding joint (51) decreases between the at least one adhesive channel (50) and the ventilation channel.
8. Insulator according to Claim 7, characterized in that the adhesive-bonding area (16) of the bearing ring (10) is conical and widens between the at least one adhesive channel (50) and the ventilation opening (52).
9. Method for producing the insulator (H) according to one of Claims 1 to 8, characterized in that the insulating tube (1) and the metal armature (2) are joined so as to form the adhesive-bonding joint (51) and the cavity (15), in that an injection aid (4) containing liquid adhesive (40) is installed in the cavity (15), and in that the liquid adhesive (40) is pressurized, using the injection aid (4), into a section of the cavity (15) which is in the form of a compression space (41) and is injected out of the compression space (41), via the at least one adhesive channel (50), into the adhesive-bonding joint (51).
10. Method according to Claim 9, characterized in that the adhesive-bonding joint (51) is formed by the metal armature (2) being shrunk onto the bearing ring (10).
11. Method according to either of Claims 9 and 10, characterized in that, after the installation of the injection apparatus (4), the insulating tube (1) which has been joined to the metal armature (2) is clamped in in a clamping apparatus (3).
12. Method according to one of Claims 9 to 11, characterized in that the liquid adhesive (40) is injected, distributed in the circumferential direction, into the adhesive-bonding joint (51).
13. Apparatus (V) for implementing the method according to one of Claims 9 to 12, characterized in that the injection aid (4) is in the form of a piston-cylinder compression apparatus and has a compression space (41), which is designed to be suitable for accommodating the liquid adhesive (40) and is delimited radially on the outside by the bearing ring (10) and axially by a cylinder base (42), which is fixed in the metal armature (2), and a piston (43), which is axially displaceable in the bearing ring (10).
14. Apparatus according to Claim 13, characterized in that a depression (44) for accommodating the liquid adhesive (40) is formed into a side of the piston (43) which delimits the compression space (41).
15. Apparatus according to Claim 14, characterized in that a plunger (46), to which pressure can be applied from the outside, rests on the side of the piston (43) which is remote from the depression (44).
16. Cooling element with a high-voltage insulator according to one of the preceding Claims 1 to 8.

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