DE19539060A1 - High-voltage, high-performance fuse for an electrical connection line - Google Patents

Description

The invention relates to a high-voltage high-performance (HH) fuse for an electrical Connection line, in particular a cable line between a transformer and a Switchgear, with a fuse housed in an insulating covering insert with connection element and with a surrounding the insulating sheath on the outside conductive cover and with a layer within the insulating sheath for dissipation of partial discharges.

In local network stations of the energy supply companies, the transformer outlets are included HV fuses protected, mostly within the enclosure of the switchgear are accommodated. This technique is complex because the security area is different from the rest Isolation room of the switchgear must be sealed gas-tight. It is also accessibility the HV fuses are very limited, and as a result of the encapsulation, there are thermal problems to count. An overheated HV HRC fuse can destroy the entire switchgear  to lead.

Switchgear versions are currently available on the market where the HV fuses housed in insulating pipes outside the remaining insulating gas space of the switchgear and are connected to this via plugs. This version requires a touch guard additional, locked metal housing, which only when the transformer switch is switched off may be removed. In addition to the considerable constructive structure, the complaint is that on the very thin fuse fuse links due to the small distances between neighboring outer conductors can discharge partial discharges that are permissible for the system Far exceed the value and make a statement on the insulation behavior of the system using Do not allow or falsify partial discharge measurements. It is also to be expected that permanent discharges on the fusible conductors due to material removal and chemical Reactions lead to permanent changes in characteristics and function.

From DE-OS 40 14 392 is a high-voltage high-performance (HV) fuse of the beginning known type known, but in which two groups of fusible conductors in two separate Chamber housings are housed and each chamber housing on the inside one high-resistance layer. This HV fuse is because of the two separate chambers complex. It also has the disadvantage that due to the high-resistance layer, which is not closer is defined, the switching behavior of the fuse can be influenced. Because the high impedance Layer lies directly in the switching room of the arc, extensive measures are required to have a negative impact on the otherwise known switching behavior of arcs in to exclude uncoated insulating pipes.

The object of the invention is therefore the HV fuse of the type mentioned to design that the switching behavior is improved, a particularly compact encapsulation the HH fuse is possible, the radial dimensions of which are commercially available, standardized Cable sets of the same nominal voltage do not exceed, and in particular from Melting conductor outgoing partial discharges through special control measures of the electric field can be limited to a permissible size.

According to the invention, this object is achieved in that the insulating sheath is a one-piece, cylindrical insulating tube and at least one of the connection elements via a Connector is connected to a cable with field control body. The well-known fuses have insulating enclosures, which disadvantageously consist of split housings, where each separation point means an electrical weak point. For example, if you leave radial  Air gaps, then you accept a much lower insulation strength. Against this the only remedy would be to increase the overall thickness of the insulation.

According to the invention, however, a one-piece insulating tube has been chosen, i. H. a one piece, unbroken insulating tube. This avoids every electrical joint, every weak point and can keep the thickness of the insulating materials smaller. If the insulating tube According to the invention is cylindrical, you can cable-fuse the HV fuse design compliant, d. H. one achieves a compact design in such a way that for commercial purposes Common cable sets available connection dimensions - especially in the radial direction - not be exceeded. As a result, the electrical properties of the Trans Formator loop not affected.

Furthermore, if a field control body is connected to a connection element, inner ones can also be used Partial discharges can be suppressed. This is achieved according to the invention to such a degree that by if the partial discharge is not reached, the product is considered to be "partially discharge free". Standard for this can be, for example, the applicable standard for cable sets with the same nominal voltage.

The design of the encapsulated HV fuse of the invention preferably corresponds to that of one Cable sleeve or that of a pluggable or screwable cable connection according to DIN VDE 0278 Part 6.

According to the invention, it is also advantageous if the insulating tube and at least one connector at least partially envelops at least one field control body. Field control body are commercially available, the placement of such a field control body in the insulating tube, which at least partially covers this, but allows a particularly compact Encapsulation with a design that conforms to cable technology. That is cheap for the space-saving Housing at switchgear or the like.

Furthermore, it is advantageous according to the invention if to limit partial discharges a field-controlling layer of semiconducting material within the insulating tube on at least a portion of the length of the insulating tube and / or the fuse link with his external securing tube is arranged. The inside of the insulating tube Field-controlling devices, for example, have components made of electrically semiconducting Materials. Such devices are used in particular in connection with the cable set technology to shut off terminations and shield connectors. The field-controlling layer of semiconducting material provides adequate field shielding of the  intact fuse element and also offers a during and after the fuse has been switched off adequate insulation between the contact caps located at the ends of the fuse sentence.

In an advantageous development of the invention, at least one connector is a conductive one Shielded electrode. The conductivity of an electrode considered here is in the range between 1 and 1000 Ωcm. This relatively high conductivity serves to ensure that there is no partial discharge electrical shielding of the connection point. When using this electrode shield an additional field-controlling layer could only be used in the area of the fuse link arrange and thus simplify the overall structure of the HV fuse. This conductive Electrodes can advantageously be installed in the insulating body, e.g. B. by pouring, gluing or the like. A similar gap-free and seamless shielding can also be achieved with a Achieve conductive lacquer coating or equivalent measures. According to the invention it is also favorable if the field-controlling layer made of semiconducting material covers the entire safety tube and covered at least one connector. In this embodiment, the insulating tube can be produced more easily if the field-controlling layer, for example, as a continuous layer Hose is formed. Alternatively, the field-controlling layer can be made according to the invention also attach semiconducting material to the safety tube; while another another embodiment, this layer also in the form of a glaze and / or in conjunction with a glaze on the porcelain safety tube. Then the Porcelain manufacturers provide the safety tube with the glaze and deliver so that the Remaining assembly at the manufacturer of the HV fuse is significantly simplified.

It is also conceivable and advantageous if, according to the invention, the field-controlling layer consists of semiconducting material as a hose over the safety tube and / or field control body is applied. You can use a standard fuse and the hose apply subsequently. For example, it is expedient for the semiconductor layer to be warm to form a shrink tube or alternatively as an elastomer tube. Leave such hoses not only produce practically but also handle, assemble and in the cheap Insert fuse assembly.

Other favorable measures for the compact design are also when one according to the invention selects a field control body whose outer diameter is approximately equal to that Outside diameter of the fuse link is. This way you can create a cylindrical one Manufacture and use insulating tube without gradations without any problems. This one or the one above mentioned field control body advantageously creates an adaptation to cables according to the invention  different conductor cross-sections and diameters, thus creating the conditions for one universal applicability and versatile use.

Field control devices consist of a mixture of electrically insulating and conductive components. The insulating components form the mechanical framework (Binder) for the conductive components.

Conductive components can e.g. B. carbon black, SiC and metal particles. They are in paints, Casting resins or elastomers integrated, the electrical Conductivity of the batch can be varied within wide limits.

Conductive varnishes are particularly suitable for application to existing construction elements (e.g. on the safety tube). From casting resins and elastomers, components such. B. the above mentioned field control electrode, prefabricated and assembled separately. Semiconducting hoses with the required properties in addition to the heat shrink sleeves mentioned mechanically pre-stressed elastomer hoses (cold shrink hoses).

The field-controlling layer forms an adequate shielding of the fuse element during the Operation and ensures sufficient insulation after the fuse has been switched off the switching distance.

If you apply the field-controlling layer in the form of the heat shrink tube, then this protrudes expediently in a preferred embodiment via the insulating tube and preferably also beyond the open end (s) of the insulating tube up to the or the field control bodies. There the hose can be connected to an earth conductor.

In a further different embodiment, the hose can be used as a pre-stressed elastomer be shrunk on the hose, e.g. B. in the form of a cold shrink tube made of silicone rubber. This hose can also be connected to the open end of the insulating tube (or its two Ends) protrude to the field control body or bodies and there preferably with a Earth conductors are connected. When using the field control hoses if they are in particular over the entire length of the fuse link, the connection points and, if available, the field control body extend, additional field control eleces are unnecessary tread over the connectors.

In a further advantageous embodiment of the invention, the insulating tube is on at least one side  open to accommodate one cable end with field control body and is on the other, not open Provide side with a plug connection for standardized device bushings. The invention therefore enables a uniform use of the plug part of the invention for everyone closed cable cross sections and cable types, because the field control body ensures that appropriate adjustment, as mentioned above.

Instead of using a fuse connector when one side is open, you can alternatively, the insulating tube open on both sides, so that the fuse as Securing sleeve works. In another embodiment, you could also on both sides of the Provide insulating pipe device connections so that the function of a safety bridge results.

It can also be advantageous if, according to the invention, the insulating tube is in the region of the Connector to the cable additionally with a plug connection for standardized device bushings is provided. As a result, the T-type design allows additional grounding of the cable. In other words, this embodiment allows a ground circuit.

Further advantages, features and possible uses of the present invention result from the following description of preferred embodiments in connection with the attached drawings. These show:

Fig. 1, the cross-sectional view of a high voltage high power (HH) Fuse as an angle connector in section and partly with broken-out,

Fig. 2 is a of FIG. 1 similar view, but of a second embodiment in which the on the ends arranged within the insulating field controlling layer in the drawing is arranged below the field control body and only about 2 cm away from the connector-side end,

Fig. 3 is a FIG. 1 similar view but of a third embodiment in which the field-controlling coating is limited to the fuse link, with overlaps to the electrodes to the field control body

Fig. 4 is a cross-sectional view taken along the line IV-IV of Fig. 1 or Fig. 5,

Fig. 5 is a sectional view through an HH fuse in the form of a locking sleeve, in which the configuration of the field-controlling layer is of similar construction inside as in the first embodiment of FIG. 1

Fig. 6 is a similar sectional view as Fig. 5, but of another embodiment with a structure of the field-controlling layer similar to that in Fig. 2, namely namely the layer in question ends about 2 cm from the connector end below and above, and

FIG. 7 again shows a view similar to FIG. 5, but similar to the internal structure of FIG. 3 of the field-controlling covering being limited to the fuse link with overlaps to the electrodes to the field control body at the top and bottom, the electrodes covering the area of the connectors.

The fuses of all embodiments have a one-piece, cylindrical insulating tube 2 as an insulating sheath under a metallic sheath 1 as the conductive cover. In the insulating tube 2 , a generally designated 3 fuse link is arranged, the contact caps 4 and 4 'carries at both ends with connecting bolts 5 , 5 '. Radially from the outside inwards, the fuse link 3 has a fuse tube 6 , quartz sand 7 as an extinguishing agent and a winding body 8 made of z. B. ceramic on which fuse element 9 are held taut.

The lower connecting bolt 5 , which, for example, can be welded, screwed or attached in a similar manner to the upper 5 ', is connected via a connector 10 to the bare conductor 11 of a cable 23 with field control body 12 , for example by pinching or screwing.

The upper connecting bolt 5 'is in the embodiments of FIGS. 5-7 (securing sleeve) with respect to the fuse insert 3 arranged in the middle arranged almost mirror image, namely via a connector 10 ' connected to a field control body 12 '.

In contrast to this, the embodiments according to FIGS. 1-3 are constructed as angled plugs, the upper connecting bolts 5 'of which are provided with a bore (with or without thread) 13 . A plug pin 14 can be inserted through this bore 13 and screwed tight. By means of socket 15 with outer cone 16 and plug 16 ', the connection to the overall designated 17 implementation is created. This angle plug-in connection of Figs. 1-3 can be screwed or plugged on the implementation 17 to a not shown transformer or switchgear. One such embodiment is a fuse in the form of a cable connector.

The insulating tube 2 covers covering in all embodiments, the fuse link 3 , including its contact caps 4 , 4 'and connecting bolts 5 , 5 ' and covers covering most of the field body 12 and 12 '. In the angular connector according to FIGS. 1 to 3 of the insulating tube 2 above a T-piece 22 to which is also insulative and the outer cone 16 and sealing plug closes covers 16 'at the substantially cylindrical portion. To limit partial discharges, a field-controlling layer 18 made of semiconducting material is arranged within the insulating tube 2 . In the embodiment of FIGS. 1 and 5, this field-controlling layer 18 extends over the entire longitudinal direction of the insulating tube 2 , ie from the field control body 12 shown below to the upper contact cap 4 '. In the embodiment of FIG. 2, this semiconducting, field-controlling layer 18 is made shorter in the lower region, ie it ends on the field control body 12 , but is about 2 cm from the lower connector 10 downwards. The situation is similar in the embodiment according to FIG. 6, although the field-controlling layer 18 (dashed line) is shorter there both above and below in the sense of FIG. 2. Therefore, in the remaining area of FIGS. 2 and 6, a layer-free annular space 19 can be seen , namely in FIG. 2 below and in FIG. 6 both below and above.

In the embodiment according to FIGS . 3 and 7, the field-controlling layer 18 only extends over the fuse link 3 . It ends overlapping on electrodes 21 , 21 '. The lower electrode 21 has a tubular shape, while a short tubular part of the upper electrode 21 '(in the case of the angled plug) is followed by a conical part which ultimately has a similar T-shape in the elbow or T-piece 22 . The upper electrode 21 'in the case of the angled plug according to FIGS . 1 to 3 therefore deviates from the simple tubular shape of the lower electrode 21 in order to overlap the upper connecting bolt 5 ', the socket 15 and the outer cone 16 with a plug 16 '. In Fig. 3 you can see in the lower region of the field control body 12 again the layer-free annular space 19 , which is also in the sleeve embodiment of FIG. 7 above, where it is called 19 '.

In all embodiments, the field-controlling layer 18 is located radially inside the insulating tube 2 and outside the fuse tube 6 of the fuse link 3 .

With regard to the electrodes or field control electrodes, one can see in all of the embodiments their simple tubular shape in the area around the field control body 12 or partially overlapping them, provided that the field-controlling layer 18 is not attached there, as in FIGS . 1, 2, 5 and 6, where the electrode is unnecessary. The simple tubular electrode 21 is therefore located in the lower region near the field control body 12 in the embodiments of FIGS. 3 and 7; in Fig. 7 and above, because the sleeve embodiment is constructed symmetrically and above a field control body 12 '.

When the angle connector design according to FIGS. 1 to 3 is located in the upper region of the passage 17, the electrode 21 described above 'with the slightly more complicated form.

The field control devices are longitudinally insulating and conduct (in the manner of a Faraday Cage) in the radial direction so that the partial discharge is deactivated.

It has already been stated above that the field-controlling layer 18 is preferably made from semiconducting material, e.g. B. as a layer on the fuse tube 6 of the fuse insert 3rd The manufacturer of the safety tubes 6 which can be produced from porcelain could alternatively apply a glaze which has field-controlling properties. Alternatively, the field-controlling layer can also be covered as a hose over the securing tube 6 , be it as a heat-shrinkable hose or as an elastomer hose. A field-controlling layer can also be applied to the inner surface of the insulating tube 2 by dipping or spraying, which would then also be provided in the assembly described here in the space between the insulating tube 2 and the parts arranged inside, such as the fuse link 3 , connector 10 and field control body 12 .

All figures show an insulating tube 2 which is open on the underside. There the end of a cable 23 with the field control body 12 is received by the insulating tube 2 .

In the embodiments according to FIGS. 5 to 7 (securing sleeve), the side of the insulating tube 2 shown above is also open, where the end of a cable 23 'is also received via the field control body 12 '.

In the embodiments according to FIGS. 1 to 3, however, the upper end of the insulating tube 2 is not open but is provided with a bushing 17 as a plug connection for standardized device bushings.

Another possible embodiment is not shown, in which the insulating tube 2 in the area of the connector 10 is additionally provided radially outward with a plug connection for standardized device bushings. There you could ground the cable 23 . The fuse could then also be used as a safety bridge.

The invention can also be expressed in such a way that a field-controlling layer 18 is arranged in the insulating tube 2 at least around the fuse link 3 . Before assembly, after the connector 10 has thus been produced, the field-controlling layer 18 would then be applied in the embodiment of FIG. 1 according to the dashed line, that is, starting from the cap 4 'down to around the field control body 12 . Then the insulating tube 2 with the upper electrode 21 'could be placed. In the case of the embodiment of FIG. 3, the field-controlling layer 18 is in turn only applied to the fuse tube 6 of the fuse link 3 , for example in the form of a prefabricated fuse link, after which the electrode 21 shown in FIG. 3 is to be applied, which covers the area of the Connector 10 engages. This would practically have a T-plug with the tubular electrode 21 attached below the fuse link 3 .

The electrode could also be regarded as an integral part of the field-controlling layer 18 , so that the starting form according to FIGS. 3 and 7 would represent a first solution principle, according to which the field-controlling layer in any case extends over the fuse link 3 ; with the second embodiment of Figures 2 and 6, in which the field-controlling layer from the area above the fuse link 3 also passes over the connector 10 or 10 and 10 '; as a third embodiment according to FIGS. 1 and 5, in which the field-controlling layer 18 from the upper cap 4 'is beyond the field control body 12 also pulled down sufficiently and in Fig. 5 of the lower field-controlling body 12 to the upper body 12' is drawn; and a further fourth embodiment corresponding to FIGS. 3 and 7, where the field-controlling layer in the region of the or the connector 10 , 10 'is designed as an electrode 21 .

Claims (11)

1. High-voltage high-performance (HH) fuse for an electrical connection line ( 23 , 23 '), in particular a cable line ( 23 , 23 ') between a transformer and a switchgear, with a covered in an insulating sheath ( 2 ) brought under Fuse insert ( 3 ) with connection element ( 5 , 5 ') and with a conductive cover ( 1 ) surrounding the insulating sheath ( 2 ) on the outside, and with a layer ( 18 ) within the insulating sheath ( 2 ) for limiting partial discharges, characterized in that that the insulating sheath is a one-piece, cylindrical insulating tube ( 2 ) and at least one of the connection elements ( 5 , 5 ') via a connector ( 10 , 10 ') with a cable ( 23 , 23 ') with field control body ( 12 , 12 ') connected is. 2. HR fuse according to claim 1, characterized in that the insulating tube ( 2 ) covers at least one connector ( 10 , 10 ') and at least partially covering at least one field control body ( 12 , 12 '). 3. HR fuse according to claim 1 or 2, characterized in that to limit partial discharges within the insulating tube ( 2 ) a field-controlling layer ( 18 ) made of semiconducting material on at least a portion of the length of the insulating tube ( 2 ) and / or the fuse link ( 3 ) with its external safety tube ( 6 ) is arranged. 4. HR fuse according to one of claims 1 to 3, characterized in that at least one connector ( 10 , 13-16 ) is shielded by a conductive electrode ( 21 ). 5. HV fuse according to one of claims 1 to 4, characterized in that the field-controlling layer ( 18 , 21 ) made of semiconducting material covers the entire safety tube ( 6 ) and at least one connector ( 10 , 14-16 ) ( Fig. 1st and 2; 5 and 6). 6. HV fuse according to claim 1 or 4, characterized in that the field-controlling layer ( 18 ) made of semiconducting material is applied to the securing tube ( 6 ). 7. HV fuse according to one of claims 1, 4 or 6, characterized in that the field-controlling layer ( 18 ) made of semiconducting material in the form of a glaze and / or in connection with a glaze on the safety tube ( 6 ) made of porcelain is applied . 8. HR fuse according to one of claims 1 to 4, characterized in that the field-controlling layer ( 18 ) made of semiconducting material as a hose over the safety tube ( 6 ) and / or the field control body ( 12 ) is applied. 9. HV fuse according to one of claims 1 to 8, characterized in that the field-controlling layer ( 18 ) made of semiconducting material is applied to the inner surface of the insulating tube ( 2 ). 10. HR fuse according to one of claims 1 to 9, characterized in that the insulating tube ( 2 ) on at least one side for receiving a cable end ( 23 ) with field control body ( 12 ) is open and on the other, not open side with a plug connection ( 14-16 ) is provided for standardized device bushings ( Fig. 1-3). 11. HR fuse according to one of claims 1 to 10, characterized in that the insulating tube ( 2 ) in the region of the connector ( 10 ) to the cable ( 23 ) is additionally provided with a plug connection for standardized device bushings.