EP3830858B1 - Fuse link and fuse - Google Patents

Description

The invention relates to the use of a fusible conductor for a high-voltage, high-performance fuse for a direct current application (HH-DC fuse/direct current fuse). Furthermore, the present invention relates to a fuse for a direct current application.

The energy supply in the coming years and/or decades will be subject to drastic structural change. This energy transition and in particular the German "energy transition" is influenced by the influence of renewable energies. The increasing share of renewable energies in the energy supply requires a restructuring of the energy supply system.

Power generation is becoming increasingly decentralized, under the influence of renewable energy (RE) plants. Many renewable energy systems generate direct current, which is then fed into an associated grid, in particular a distribution grid.

For the safe use of a direct current network, which is fed by renewable energy systems, for example, permanent protection of the direct current or the direct current application is required.

Securing the direct current is not only required for distribution grids that are fed by renewable energy systems, but also in principle for distribution grids that work with direct voltage. AC transmission or an AC network is currently common on the market. However, this will change in the coming years or decades.

The reason for this is that direct current transmission is preferred for power transmission over comparatively long distances in terms of reduced transmission loss from a technical point of view. A high-voltage direct current transmission connection (HVDC connection) and/or medium-voltage direct current transmission connection (HVDC connection) for power transmission is therefore particularly suitable for connecting offshore systems. Such power transmission occurs at the transmission level. In order to connect the consumers and in particular the households, however, there is a handover from the transmission level to the distribution level. Also the distribution level, which is the direct current received from the transmission level must be permanently secured under high technical requirements.

A restructuring of the grid from AC voltage to DC voltage therefore poses the challenge of securing the DC voltage at the distribution grid level, so that the households and/or the electrical consumers and/or the energy systems, in particular the renewable energy systems, are securely connected to the DC distribution grid can be connected.

Also for the integration of electric vehicles and/or the integration of power plants and decentralized power generators, efficient and safe securing of the direct current distribution network is a decisive factor in the overall implementation of the energy transition or the restructuring of the energy market.

One of the greatest challenges here is securing the direct current network or the direct current application. Ultimately, without such a safeguard, the concepts for direct current transmission and in particular for the decentralization of power generation and the feed-in of the decentralized power plants or energy systems cannot be implemented. DC fuses for direct current applications, especially at the distribution grid level, are a technical anchor point for safe grid operation.

However, with current direct current applications, it is disadvantageous that in practice—if at all—only insufficient or at most adequate protection of the direct current transmission and/or the direct current application can be guaranteed. Especially for a direct current application at the distribution grid level, there are no known fuses that on the one hand withstand the long-term load of the direct current transmission and on the other hand can safely switch off the transmitted direct current in the event of a short circuit. Consequently, direct currents cannot be secured effectively, in particular in sections and/or in the case of a compact, small-sized and/or short-length design.

However, not only switching off in the event of a short circuit, but also switching off in the event of an overload (overload switching) is necessary for long-term protection of the direct current application. Overload currents are currents that exceed the rated value of the consumers in the DC distribution system, in particular the equipment, a system, cables and/or lines, without there being a short circuit.

A fuse for a direct current high voltage that enables overload and short-circuit protection at the same time is not known in the prior art. However, this would be necessary for safe operation of the DC distribution network and the DC transmission line. Without overload protection, the consumers to be protected, such as equipment, cables and/or lines, cannot be prevented from heating up in continuous operation. Thus, in the event of an overload and/or during a short circuit, the pickups are exposed to high thermal and mechanical stresses.

For the low-voltage range, fuses for use in DC voltage circuits are known in the prior art. However, these are not suitable or usable for the high-voltage and/or medium-voltage direct current range. the EP 3 270 403 A1 relates, for example, to such a low-voltage fuse for a DC voltage circuit.

the US 3,766,509A relates to a fuse for protecting an AC voltage.

the WO 2015/183805 A1 relates to the use of a fuse for the DC range according to the preamble of claim 1.

the US 5,892,427A relates to a fusible conductor that has short-circuit bottlenecks and overload bottlenecks.

the GB 1 326 535 A relates to a fusible conductor that has overload and short-circuit bottlenecks.

the FR 2 958 073 A1 also relates to a fusible conductor that has overload bottlenecks and short-circuit bottlenecks.

It is now the object of the present invention to avoid the aforementioned disadvantages in the prior art or at least to substantially reduce them.

According to the invention, the above object is achieved by using a fusible conductor for a DC fuse (a fuse for direct current transmission) according to claim 1 and a high-voltage high-performance fuse (the so-called HH-DC fuse) according to claim 10. The fusible conductor has an electrically conductive fusible wire. The fusible wire has at least two overload constrictions designed as cross-sectional constrictions. In at least a first section, a first layer is provided which surrounds the outer surface of the fusible wire circumferentially at least in regions, preferably completely. The first layer has and/or consists of solder as the material. The at least one first section is preferably provided between the two directly consecutive transmission points. Adjacent to each of the overload constrictions, a second layer is provided in a second section, surrounding the outer jacket surface of the fusible wire circumferentially at least in regions, preferably completely.

According to the invention, the fusible wire is not fixed or restricted to a specific geometric shape and/or to a specific cross-sectional shape. In particular, the fuse wire is not limited to a circular and/or elliptical cross-sectional shape. The fusible wire can preferably be designed as a flat wire and/or flat strip. Alternatively or additionally, it can be provided that the fusible wire is at least essentially cylindrical and/or has an at least essentially circular cross-sectional shape.

In particular, the first layer is electrically conductive and/or the second layer is electrically insulating.

Particularly preferably, the overload constriction points are arranged one after the other, running in the longitudinal direction of the fusible wire. When used in a DC fuse, the fusible conductor enables a direct current to be switched off in a very short time frame, in particular between 10 ms and 1 second. More preferably, an overload shutdown can take up to one hour.

The entire fusible conductor preferably has only a single first section which has the first layer and is preferably arranged at least essentially in the middle of the length of the fusible conductor.

Alternatively or additionally, it can be provided that a plurality of first sections having the first layer are provided.

In particular, the arrangement of the first section can be provided independently of the arrangement of the transmission points.

According to the invention, it has been found that the minimum turn-off current can be significantly reduced by arranging the overload bottlenecks in combination with the first and second layers. Ultimately, this enables the use of the fusible conductor in HH-DC fuses, which can be used both for short-circuit disconnection and for overload disconnection. The short-circuit protection can be made possible by the fuse in that the largest short-circuit currents can be reliably interrupted at their installation point. The overload protection, in turn, can be current-dependent through the first layer, with the breaking capacity for overload protection generally being able to be smaller than the short-circuit current at the installation point of the fuse.

The use of further means to protect a direct current application and in particular to ensure overload protection can be avoided. Further circuit breakers or the like are not needed and/or such a need is reduced. According to the invention, a direct current transmission network can be secured efficiently. In addition, according to the invention, it can be used as back-up protection, in particular without the need to supply energy, in particular external energy, for actuation.

According to the invention, high direct currents and/or high direct voltages can be secured with the fusible conductor used in the fuse. The minimum breaking current, which can also be referred to as the smallest breaking current, can be kept very low.

The rated value of the minimum breaking current is to be understood as the smallest breaking current. From this current level, the fuse is able to switch the overcurrent. As a result, the electrical components (customers, direct current source, etc.) must be arranged and/or designed on the fuse in such a way that no overcurrent that falls below the minimum breaking current can occur at the installation point of the fuse. The smallest breaking current can depend on the type of fuse selected.

In addition, the length of the fusible conductor required for an HH-DC fuse can be drastically reduced by the arrangement of the second layer according to the invention. The length of the fusible conductor required for an HH DC fuse can depend in particular on the rated voltage of the fuse. The length of the fusible conductor can preferably be reduced by at least 10%, preferably 20%, more preferably 30% by the arrangement according to the invention.

Accordingly, it is possible according to the invention to switch off comparatively low currents of the direct current at a high direct voltage. This is necessary precisely for a wide range of uses and for a safeguard to be guaranteed over a "broad" current range.

When the invention came about, it was surprisingly found that the inventive design of the fusible conductor makes the fuse, which has the fusible conductor, particularly suitable for direct current use, in particular for securing a direct current distribution network. In this way, high direct currents and/or high direct voltages can be secured. As explained above, no fuse is known in the prior art that can secure a direct current application, in particular in the high-voltage, high-power range. In particular, securing in the medium-voltage and/or high-voltage area is associated with a large number of requirements and standards that must be observed. A high degree of sensitivity and caution with regard to the risk potential resulting from high voltages or currents has meant that fuses have not been used "randomly" or at all for the transmission and/or distribution of different types of current. In particular, there has not been a sufficient solution for direct current transmission due to the expected problems.

If one of the customers and/or consumers electrically connected to the direct current distribution network caused a short circuit and/or had an overload, the entire direct current network would fail—at least after a certain time. Even if the direct current network does not fail immediately, high thermal and/or mechanical loads on the connected customers and/or consumers cannot be prevented. Accordingly, in the practice of fuses in DC networks or refrained from direct current distribution and/or direct current transmission, since the security required for a stable and safe power grid or direct voltage circuit could not be permanently guaranteed.

Surprisingly and unforeseeably, however, it has been found according to the invention that the special fusible conductor according to the invention can be used in an HH fuse and/or in a fuse for a DC application, with the necessary safety being able to be guaranteed, particularly in the event of overload and in the event of a short circuit. It has been found that in the event of an overload and also in the event of a short circuit, damage to the fuse housing of the fuse, in particular the HV HRC fuse, possibly associated with an escape of extinguishing agent and/or an arc, can be prevented. In simulated long-term tests, it has been found that even with long-term use of the fuse having the fuse element according to the invention to secure a direct current application, for example for a period of more than five years, preferably more than ten years, more preferably more than 15 years, the statutory requirements, in particular, are required safety guidelines and/or regulations can be complied with. In particular, the fuse having the fuse element according to the invention can be used maintenance-free.

According to the invention, a fuse can therefore be provided which can be used for a direct current application in the medium-voltage and/or high-voltage level. In particular, the fusible conductor according to the invention makes it possible to connect a plurality of consumers and/or consumers and/or generators (e.g. EE systems) to the DC connection or to the DC voltage circuit, which are protected by at least one fuse having the fusible conductor. If a consumer fails, especially in the event of a short circuit, the DC network does not collapse. In this way, the security of supply in particular can be guaranteed.

Sections of the DC network can preferably be protected by means of the fuse having the fusible conductor according to the invention. Due to the fusible conductor, the fuse having the fusible conductor is designed as a fuse. The fuse is an overcurrent protection device that interrupts the circuit by melting the fuse element if the current intensity exceeds a certain value for a sufficient time. The time required to switch the fuse is preferably very short, in particular in the millisecond range.

In principle, the fusible conductor can also be used in a fuse to switch off alternating current (AC fuse / alternating current fuse). Ultimately, however, this use is not indicated for the alternating current due to an overdimensioning—achieved according to the invention. In particular, the fusible conductor according to the invention is not technically necessary when used in a fuse for protecting AC transmission.

In relation to its length, the fusible conductor provides a relatively high resistance compared to the rest of the network, in particular the direct current distribution network, which in nominal operation leads to heating and melting in the event of an overload or in the event of a short circuit.

The formation of the cross-sectional constrictions in combination with the first and second layer can influence the behavior of the fusible conductor in a manner according to the invention such that the fusible conductor is suitable for securing direct current transmission, particularly in the high-voltage range.

In addition, the fusible conductor can be designed in such a way that it can be operated permanently at higher temperatures—compared to low-voltage fuses.

The behavior of the fusible conductor in the overload range can be advantageously influenced by the overload bottlenecks. Particularly preferably, the overload constrictions are ultimately elongated, in particular by being punched out using square dies, so that the length of the cross-sectional constriction and the "web width" (width of the cross-sectional constriction) can be used to set a faster or slower response.

The first layer can also be applied to the fusible wire or to the outer surface of the fusible wire circumferentially only in regions, in particular only on the top and/or underside of a fusible wire designed as a flat strip. In this case, the first layer can form an at least essentially elliptical, preferably circular, first section—seen in cross section.

The second layer is preferably formed in the second section in such a way that it at least essentially completely surrounds the fuse wire (at least in the second section). The second layer can have an at least essentially ring-shaped and/or hollow-cylindrical shape. The second layer and the second section preferably directly adjoin the overload constriction, so that the overload constriction, which is designed as a cross-sectional constriction, is at least essentially directly connected to the second section. However, the second section preferably does not extend into the area of the overload constriction point having the reduced cross section.

In particular, the first section can be provided at least essentially in the middle between the second sections and/or between the immediately consecutive overload constrictions.

Alternatively or additionally, a single first layer is particularly preferably provided in the first section for each fusible conductor in a first embodiment, the arrangement of which is in particular independent of the cross-sectional constrictions and/or in particular is present at least essentially in the middle of the fusible conductor. In further embodiments, at least two first layers can be provided for each fusible conductor, with the first section having the first layer being arranged independently of the cross-sectional constrictions and/or centrally—seen in the longitudinal direction of the fusible wire—on the fusible wire.

According to the invention, it is provided that the fusible wire has at least one short-circuit constriction designed as a cross-sectional constriction between two immediately consecutive overload constrictions. In particular, the short-circuit constriction enables the fuse having the fusible conductor according to the invention to be switched in the event of a short-circuit.

The minimum width and/or the shape of the cross-sectional constriction of the overload constriction preferably differs from the minimum width and/or the shape of the cross-sectional constriction of the short-circuit constriction.

Alternatively, the minimum width and/or the shape of the cross-sectional constriction of the overload constriction can correspond at least essentially to the minimum width and/or the shape of the cross-sectional constriction of the short-circuit constriction.

According to the invention, the provision of the at least one short-circuit point enables the fuse to react quickly, in particular in the event of a short-circuit. Depending on the configuration of the short-circuit constriction, a quicker or less quick-acting short-circuit behavior can be set. The level of the let-through current in the event of a short circuit can also be set to a large extent by the minimum width and/or the constriction width of the short circuit constriction.

It is preferably provided according to the invention that the minimum width of the cross-sectional constriction of the overload constriction is greater than the minimum width of the cross-sectional constriction of the short-circuit constriction. This allows the fuse having the fusible conductor to switch both in the event of a short circuit and in the event of an overload, since a different configuration of the cross-sectional constrictions of the short-circuit constriction and the overload constriction can ensure corresponding fuse behavior for short-circuit disconnection.

Ultimately, it goes without saying that the narrowing of the cross section of the overload constriction and/or the short-circuit constriction does not have to have a constant width. The minimum width of the cross-sectional constriction is to be understood as meaning the smallest width in each case.

When the invention came about, it was found that the ratio of the minimum width of the cross-sectional constriction of the overload constriction to the minimum width of the cross-sectional constriction of the short-circuit constriction is between 0.01:1 and 3:1, preferably between 1.1:1 and 2:1, more preferably between 1.15 to 1.5:1. The aforementioned conditions ensure in particular that overcurrent protection is ensured both in the event of a short circuit and in the event of an overload by switching off the current, in particular the direct current.

Alternatively or additionally, it can be provided that the minimum width of the cross-sectional constriction of the overload constriction is between 0.3 to 1.5 mm, preferably between 0.4 to 1 mm, more preferably between 0.5 to 0.7 mm and in particular at least essentially 0 .6mm.

The minimum width of the narrowing of the cross section of the short-circuit constriction can be between 0.25 to 1.3 mm, preferably between 0.4 to 1 mm, more preferably between 0.5 to 0.6 mm, in particular at least essentially 0.5 mm. A ratio of the minimum width of the cross-sectional constriction of the overload constriction to the minimum width of the cross-sectional constriction of the short-circuit constriction of 0.6:0.55—that is, approximately 1.09:1—is particularly preferred.

As mentioned above, it can be provided according to the invention that the minimum widths of the cross-sectional constriction of the short-shot constriction and that of the overload constriction at least essentially correspond or are of the same design.

Provision is very particularly preferably made for the cross-sectional constriction of the overload constriction and/or the short-circuit constriction to be homogeneous, in particular over the length of the constriction. The cross-sectional constriction is preferably formed or produced by a punched-out portion having a straight and/or curved edge.

In a further preferred embodiment it is provided that the cross-sectional constrictions of the overload constrictions and/or the short-circuit constrictions are designed at least essentially identically.

Preferably, the second layer and/or the second section is at least substantially directly adjacent to the respective overload constriction, in particular with the respective second layer being provided directly adjacent to each overload constriction. In particular, according to the invention, immediate adjoining also means that a small distance is provided between the second section and/or the second layer and the overload constriction, which in particular is less than or equal to the length of the respective overload constriction is. Such an arrangement makes it possible in particular that a very low minimum turn-off current can be achieved.

In addition, in a further preferred embodiment of the idea of the invention, it is provided that the second layer is firmly, preferably cohesively, connected to the outer jacket surface of the fusible wire. Ultimately, the second layer can be glued to the outer surface of the fusible wire, in particular the second layer has been dripped onto the outer surface of the fusible wire. In particular, the second layer adheres to the outer surface of the fusible wire.

In a further particularly preferred embodiment, it is provided that the second layer has and/or consists of a plastic and/or poly(organo)siloxane (also called silicone) as the material, preferably as an arc extinguishing agent. Furthermore, the second layer can be designed to be electrically insulating.

In particular, the minimum turn-off current or the lowest turn-off current can be reduced by the combination of the solder of the first layer and the silicone or the material of the second layer. According to the invention, a significant increase in the rated voltage of the DC fuse in the event of a short circuit can be achieved by using the silicone-containing second layer on the fusible wire, assuming a predetermined product of the direct current secured by the DC fuse and the direct voltage.

By using the solder in the first coating, the melting point of the fusible conductor can also be reduced to values where the silicone in particular is present in its "pure form" at least essentially undamaged. If the first layer had no solder, a fusible conductor temperature in the range of the melting temperature of the material of the fusible wire—for example, in the case of pure silver: 961° C.—would have to be reached even in the event of an overload. In this case, there would be a risk that the material of the second layer—namely the silicone—can no longer be used as an extinguishing arc agent or as an extinguishing medium.

The solder of the first layer can have and/or consist of metal, in particular a metal alloy, as the material. In particular, the metal alloy contains cadmium, lead, tin, zinc, silver and/or copper. A metal alloy containing tin and/or silver is particularly preferred. The first layer can also preferably serve to weaken the physico-chemical processes in the event of an overload, in order in particular to enable shutdown—this is also known as the M effect.

When choosing the first layer, legal directives - such as the EU RoHS directive - which restrict the use of hazardous substances in electronic devices must also be taken into account. This particularly applies to materials such as cadmium and/or lead.

In the event of overload currents, the greatest amount of heat generated by the material of the solder, in particular the tin or the tin-silver alloy, occurs in the area of the second section, in particular in the area where the tin is applied. When the melting temperature is exceeded, the tin and/or silver becomes liquid and forms an alloy with the material of the fuse wire. Compared to the material of the fusible wire, this alloy has a lower electrical and thermal conductivity and, in particular, a lower melting point. As a result of the further increasing heat generation, the fusible conductor or the fusible wire becomes molten at the corresponding point below the actual melting point and separates the current path. This phenomenon was discovered by Metcalf in 1939, which is why it is also known and referred to as the M effect. By applying the first layer to the fusible wire, a fuse can use the previously described M-effect to trigger the fuse.

A plurality of short-circuit bottlenecks is very particularly preferably provided between two immediately consecutive overload bottlenecks. In particular, between 2 to 15, preferably between 3 to 6, short-circuit constrictions are provided between two immediately consecutive overload constrictions.

Alternatively or additionally, it can be provided that the first section having the first layer--at least once in the fusible conductor--between two directly consecutive short-circuit constrictions, preferably centrally between directly consecutive short-circuit constrictions and/or centrally between two consecutive overload constrictions, on the outer surface of the fuse wire.

In further embodiments, the first layer can be arranged independently of the short-circuit bottlenecks and/or the overload bottlenecks on the outer surface of the fusible wire.

The large number of short-circuit bottlenecks ensures that the current, in particular the direct current, is switched off safely when the fusible conductor is used in the fuse.

The second sections having and/or forming the second layer are preferably arranged on the outer surface of the fusible wire in such a way that the two overload constrictions and preferably the short-circuit constriction arranged between the overload constrictions and/or the short-circuit constrictions are located between two directly consecutive second sections and/or second layers are provided. As a result, an arrangement in the form of a second layer or second section—overload constriction—if appropriate, at least one short-circuit constriction—overload constriction—second layer or second section is particularly preferred.

In a further particularly preferred embodiment, the overload constriction is formed by recesses having an at least substantially rectangular edge.

Alternatively or additionally, the short-circuit constriction can also be formed by a recess having an at least substantially rectangular edge.

In particular, the cross-sectional constriction of the overload constriction and/or the short-circuit constriction can be formed by punchings that have an at least substantially rectangular edge. In particular, the corners of the rectangular contour of the recesses can be formed at least essentially in the shape of circular arc sections or rounded. The recess can be punched out, for example, by means of square stamps.

The short-circuit constriction and/or the cross-sectional constriction of the short-circuit constriction is/are preferably formed by a cut-out having an edge that is at least essentially in the shape of a circular arc segment.

As an alternative or in addition, the cross-sectional constriction of the overload constriction can also have the above-mentioned circular-arc segment shape.

The recess in the form of a circular arc can also be achieved by punching, preferably by means of round punches. In particular, the short-circuit bottleneck and/or the overload bottleneck is designed as an at least substantially round short-circuit bottleneck and/or the overload bottleneck.

At least two recesses are preferably provided for each cross-sectional constriction of the overload constriction and the short-circuit constriction. The cutouts can be arranged opposite one another, with the two cutouts per cross-sectional constriction of the overload constriction and the short-circuit constriction in particular being at least essentially the same and in particular being arranged mirror-inverted to one another, with the cut-out being able to be mirrored along the central axis of the fuse wire.

Ultimately, the overload bottlenecks configured as a cross-sectional constriction and/or the short-circuit bottlenecks configured as a cross-sectional constriction can be configured at least essentially identically.

Since the respective cross-sectional constrictions of the overload constriction and/or the short-circuit constriction have an at least essentially identical heat exchange, it can happen that the fuse element melts at different points of the fuse wire in the event of an overload or short-circuit, in particular depending on the overcurrent. The excess current flows through the fusible wire and causes it to heat up.

For example, a cutout in the shape of a circular arc in the short-circuit bottleneck with at least essentially the same cross-sectional width and/or the same cross-sectional length can dissipate the heat better than an overload bottleneck that has an at least essentially rectangular cutout, since the short-circuit bottleneck in particular contains "more material". In the case of a very high overload current, however, the minimum width of the narrowing of the cross section is particularly important an extremely relevant parameter, especially more relevant than the shape of the neck, since the neck first melts in the middle and not homogeneously.

It can be expected that when an overcurrent is present, some cross-sectional bottlenecks will melt faster than others. By combining different configurations of the cross-sectional constrictions of the overload constriction and the short-circuit constriction, a reaction curve of the fuse having the fuse element according to the invention can be obtained, which takes into account in particular the reaction curve or the response behavior of the individual cross-sectional constrictions and represents a superimposition of just those individual reaction curves.

In the case of very high overcurrents - i.e. in the case of a short circuit - those cross-sectional constrictions with the smallest minimum width, i.e. in particular the short-circuit constrictions, melt first. With a lower overcurrent and a somewhat "longer" switch-off time, the shape, in particular the length and the special geometry, of the cross-sectional constrictions is "taken into account" more. In this case, it is provided that the cross-sectional constrictions of the overload bottlenecks will melt in the event of an overload due to the at least essentially rectangular shape of the recesses before the short-circuit bottlenecks. The fusible conductor can accordingly enable the direct current that is secured by the fuse to be switched off, preferably depending on the respective fuse behavior.

In a further very particularly preferred embodiment, it is provided that the short-circuit constrictions arranged between the immediately successive overload constrictions are at least essentially regularly spaced. As a result, the distance between two directly consecutive short-circuit bottlenecks in the area between two immediately adjacent overload bottlenecks can be at least essentially the same. This enables the short-circuit current to be switched off safely via the fusible conductor.

Alternatively or additionally, it can be provided that the distance between two immediately adjacent short-circuit bottlenecks and/or the distance between a short-circuit bottleneck and the immediately adjacent overload bottleneck is at least is essentially the same. An equal distance between immediately adjacent or directly consecutive short-circuit bottlenecks enables the short-circuit bottlenecks to be spaced regularly from one another. The identical distance between a short-circuit constriction and the immediately adjacent overload constriction can in any case also be at least essentially the same if only one short-circuit constriction is arranged between two directly consecutive overload constrictions. In this case, the short-circuit bottleneck would then be arranged at least essentially centrally between the overload bottlenecks.

Preferably, the distance between a cross-sectional constriction of the short-circuit constriction and/or the overload constriction and the directly adjacent cross-sectional constriction of the short-circuit constriction and/or the overload constriction is at least substantially the same. Particularly preferably, the cross-sectional constrictions of the overload constrictions and the short-circuit constrictions of the fusible conductor are at least essentially regularly spaced. This enables a simplified production of the cross-sectional constrictions by punching out the fusible wire, while at the same time the behavior in the event of overload and in the event of a short circuit is ensured by switching off the current, in particular the direct current, by melting the fusible conductor.

Provision is particularly preferably made for the distance between directly adjacent cross-sectional constrictions of the overload point and/or the short-circuit constriction to be between 1 and 50 mm, preferably between 5 and 30 mm, more preferably between 10 and 20 mm and in particular at least essentially between 16 and 18 mm . The aforementioned distance can in particular be the distance between directly adjacent short-circuit bottlenecks and/or the distance between an overload bottleneck and the directly adjacent short-circuit bottleneck.

Alternatively or additionally, it can be provided that the distance between immediately adjacent overload constrictions is between 20 to 150 mm, preferably between 40 to 100 mm, more preferably between 50 to 80 mm, in particular at least essentially between 60 to 70 mm.

Furthermore, the length of the cross-sectional constriction of the overload constriction can be greater than the length of the cross-sectional constriction of the short-circuit constriction be. Very particularly preferably, the length of the cross-sectional constriction of the overload constriction to the length of the cross-sectional constriction of the short-circuit constriction has a ratio of between 1:0.3 and 1:0.9, preferably between 1:0.5 and 1:0.85, more preferably between 1: 0.7 to 1:0.8 and in particular at least essentially 1:0.75. Due to the greater length of the overload constriction, switching off in the event of an overload can be ensured by changing the fusible wire when it heats up. The increased length, in particular in combination with the minimum width of the overload constriction and the shape of the overload constriction, makes it possible for the case of overload to be secured by melting of the fusible conductor even if no short circuit occurs.

In particular, a faster response of the fusible conductor in the event of an overload can be made possible by the extended web length.

The first and/or the second layer is particularly preferably designed as a coating. A coating using the material of the first and/or the second layer enables a targeted and purposeful application in the first and/or in the second section and thus provides in particular a possible application that completely surrounds the fusing wire in some areas or circumferentially with the first and/or second layer for sure. The first and/or second layer can be applied in a targeted manner in their respective sections, in particular in-line production being made possible by a coating application.

In addition, the length of the narrowing of the cross section of the overload constriction can preferably be between 1 and 5 mm, preferably between 1.5 and 3 mm, in particular with the length of the overload constriction being at least essentially 2 mm.

In a further particularly preferred embodiment of the idea of the invention, the fusible wire has an at least essentially rectangular cross-sectional shape. Alternatively or additionally, it can be provided that the fusing wire is in the form of a flat strip, in particular in which case the width or the height of the flat strip can be 0.04±0.02 mm. The fusible wire designed as a flat strip can—produced by punching out, in particular by means of stamping—have the recesses of the overload bottleneck and/or the short-circuit bottleneck.

In an alternative embodiment it can be provided that the fusible wire has an at least essentially circular outer cross section. In particular, in this embodiment, the first and/or the second layer can have an at least essentially circular outer cross section.

A metal is preferably provided as the material of the fusible wire. The material of the fusible wire can also be referred to as fusible wire material. The fusible wire material preferably contains silver and/or a silver alloy.

As an alternative or in addition, the fusible wire can have and/or consist of an electrically conductive material, in particular copper and/or a copper alloy.

At least essentially pure silver is particularly preferably used. The degree of purity of the silver can be greater than 99%. In particular, the degree of purity of silver is greater than 99.9%, particularly preferably at least essentially equal to 99.99%. A silver purity of 99.99% indicates the amount of silver (Ag) in the material. Accordingly, the silver is preferably in the form of fine silver.

Alternatively or additionally, it can be provided that the fusible wire has and/or consists of copper and/or a copper alloy.

The melting temperature of the material of the fusible conductor can be greater than 900°C, in particular between 950 to 970°C, in particular the melting temperature of the fusible wire can be 961°C. The density of the material of the fusible wire can be at least essentially 10.5 g/cm ³ .

The use of pure silver, in contrast to copper, which can be used as the material for the fusible wire in low-voltage fuses, is advisable due to the permanently higher temperatures that occur when operating an HV HRC fuse. The use of copper could be in a high voltage fuse lead to oxidation of the surface and in particular have fatal consequences when switching off, especially the direct current.

The fusible conductor for use in an HH-DC fuse preferably has a length of more than 500 mm, preferably a length of between 500 mm and 3000 mm, more preferably between 1000 mm and 2500 mm, in particular at least essentially between 1500 mm and 2000 mm mm, up. The fusible conductor can be designed in such a way that it can be wound helically onto a winding former, so that the length of the fuse can be less than the length of the fusible conductor.

It is particularly preferred that an alternation of immediately consecutive overload bottlenecks is provided for the fusible conductor. The at least one short-circuit bottleneck and/or the short-circuit bottlenecks are preferably arranged between two immediately consecutive overload bottlenecks. In particular, it is provided that the overload bottlenecks are at least essentially regularly spaced apart—that is to say have an at least essentially constant distance from one another. The aforementioned design of the fusible conductor with the alternating sequence of the overload bottlenecks can lead to behavior of the fuse in the event of an overload and a short circuit that can be easily predetermined. The production of the fusible conductors having the cross-sectional constrictions is also simplified by the regular, sequential arrangement of the cross-sectional constrictions of the overload constriction and the short-circuit constriction.

In the case of a sequential arrangement of the overload constrictions, the first section is arranged in particular at least once, preferably once, between a pair of overload constrictions.

In the case of a sequential arrangement of the overload bottlenecks in the fuse element, it is preferably provided that the sequence of the overload bottlenecks with short-circuit bottlenecks arranged between them is at least essentially regular and/or structurally identical.

The ratio of the maximum width of the fusible wire to the minimum width of the cross-sectional constriction of the overload constriction and/or the cross-sectional constriction of the short-circuit constriction is preferably between 1:0.6 and 1:0.2 between 1:0.5 to 1:0.3, more preferably between 1:0.4 to 1:0.35. The fusible wire can in particular have a maximum width of greater than 0.6 mm, preferably between 1 mm and 2 mm, more preferably at least essentially 1.6 mm.

Furthermore, the present invention relates to an HH DC fuse for securing a direct current transmission with an outer fuse housing. At least one fusible conductor wound around an in particular electrically insulating winding body is arranged in the fuse housing according to at least one of the previously described embodiments.

It goes without saying that a plurality of fusible conductors can also be arranged around the winding body. The fusible conductor preferably has a plurality of overload constrictions, which can be regularly spaced apart from one another.

It goes without saying that the aforementioned preferred embodiments of the fusible conductor according to the invention and/or the advantages described in connection with the fusible conductor according to the invention can also be used in the same way for the fuse according to the invention. In order to avoid unnecessary repetitions, reference is made to the preceding explanations with regard to statements in this regard.

In a preferred embodiment of the invention, it is provided that the fuse housing is at least partially open on two end faces, with at least one contact cap designed for electrical contact being arranged on the end face of the fuse housing.

As explained above, the preferred winding of the at least one fusible conductor allows the length of the fuse to be kept as short as possible, in particular the length of the fuse being between 300 mm and 1000 mm, preferably between 500 mm and 600 mm.

The required length of the fusible conductor, which does not correspond to the entire length of the fuse, is used to transmit the DC voltage because the fusible conductor is ultimately wound around the winding body. Ultimately, the length of the fusible conductor is greater or much greater than the length of the fuse. The winding body is preferably designed in such a way that the fusible conductor rests at certain points—possibly at a plurality of contact points—in particular at least essentially in each turn. Accordingly, the winding body can have projections and depressions resulting between the projections. An at least essentially star-shaped configuration of the winding body is very particularly preferred.

The DC voltage of the transmitted direct current and/or the rated voltage or the rated voltage range of the fuse is preferably greater than 1 kV, preferably greater than 1.5 kV, more preferably greater than 5 kV. Alternatively or additionally, it is provided that the DC voltage and/or the rated voltage of the fuse is less than 150 kV, preferably less than 100 kV, more preferably less than 75 kV, and/or between 1 kV and 100 kV, preferably between 1.5 kV to 50 kV, more preferably between 3 kV to 30 kV. The rated voltage or rated voltage range of the fuse is to be understood in particular as the voltage or the voltage range at which the fuse is used and/or has been tested for the fuse. A basic distinction must be made between an upper rated voltage and a lower rated voltage, with the lower rated voltage specifying the voltage at which the fuse still switches, while the upper rated voltage represents the upper limit for the DC voltage to be transmitted. Consequently, the rated voltage or the rated voltage range indicates the permissible voltage range of the fuse. In particular, the rated voltage range corresponds to the DC voltage range that can be protected by the fuse.

In a further particularly preferred embodiment it is provided that the smallest breaking current of the fuse is greater than 3 A, preferably greater than 5 A, more preferably greater than 10 A. Alternatively or additionally, it is provided that the smallest breaking current of the fuse is less than 1 kA, preferably less than 500 A, more preferably less than 300 A, and/or between 3 A and 700 A, preferably between 5 A and 500 A, more preferably between 15 A to 300 A.

Alternatively or additionally, it can be provided according to the invention that the smallest breaking current of the fuse is greater than or equal to the rated current intensity, in particular greater than or equal to twice the rated current intensity, preferably is greater than twice and/or less than 15 times the rated current intensity, more preferably greater than three times and/or less than eight times the rated current intensity. The aforesaid relative dimensioning of the smallest breaking current is advantageous in that, in particular, the smallest or minimum breaking current is directly dependent on the rated current intensity of the respective fuse link.

The rated switching capacity is preferably greater than 1 kA, preferably greater than 10 kA, more preferably greater than 20 kA, and/or is between 1 kA and 100 kA, preferably between 10 kA and 80 kA, more preferably between 10 kA and 50 kA . The rated switching capacity of the fuse is to be understood in particular as the rated value of the largest breaking current. The largest breaking current is the maximum direct current that the fuse can still switch. Consequently, the rated switching capacity of the fuse should be greater than the maximum short-circuit current at the point of use of the fuse.

In addition, according to a further embodiment of the inventive idea, the direct current that is transmitted and secured by the fuse and/or the rated current range is greater than 5 A, preferably greater than 10 A, more preferably greater than 15 A. Alternatively or additionally, it is provided that the direct current is between 3 A to 100 kA, preferably between 10 A to 75 kA, more preferably between 15 A to 50 kA. In particular, the range of the current strength of the direct current to be transmitted is specified as a function of the rated switching capacity and the smallest breaking current of the fuse.

Ultimately, it goes without saying that, depending on the respective direct current transmission, different fuses can also be provided, which can be designed for the respective application. The type of fuse can be selected depending on the direct current to be transmitted and/or the direct voltage.

Furthermore, the product (mathematical multiplication) of the direct current secured by the fuse and the direct voltage is preferably greater than 5 kW, preferably greater than 50 kW, more preferably greater than 700 kW. Alternatively or additionally, it is provided that the product is secured by the fuse Direct current and direct voltage is less than 3000 MW, preferably less than 2000 MW, more preferably less than 1000 MW, and/or between 5 kW and 3000 MW, preferably between 500 kW and 2000 MW, more preferably between 700 kW and 1000 MW.

In particular, the product of the direct current secured by the fuse and the direct voltage can correspond to the power of the consumer and/or consumers secured by the fuse (total power). Ultimately, the aforementioned product corresponds in particular to the performance that can be secured by the fuse.

According to a further preferred embodiment, it is provided that the fuse has at least two fusible conductors, preferably between 2 and 10 fusible conductors, more preferably between 3 and 5 fusible conductors, which are arranged in the fuse housing. In particular, the fusible conductors are electrically connected to one another and/or to the contact cap.

The direct current application is particularly preferably a medium-voltage direct current distribution and/or a high-voltage direct current distribution. Consequently, the fuse can be used in networks arranged in the medium-voltage direct current range and/or in the high-voltage direct current range. A medium-voltage direct current range is to be understood in particular as a direct voltage of greater than 1 kV, preferably greater than 2 kV, more preferably greater than 3 kV, and/or less than 50 kV, preferably less than 40 kV, more preferably less than 30 kV. A high-voltage direct current range is to be understood in particular as a voltage range of more than 60 kV, preferably more than 100 kV, more preferably more than 200 kV.

The fuse can preferably be arranged in a medium-voltage direct current distribution network, in particular in a medium-voltage direct current system. At least one direct current device, in particular an MVDC device (Medium Voltage Direct Current Device, in German: medium-voltage direct current device), can be arranged in the medium-voltage direct current distribution network. The direct current can be made available to the medium-voltage direct current transmission network by an energy conversion plant.

Alternatively or additionally, it can be provided according to the invention that the direct current from a photovoltaic system and/or a photovoltaic area system, in particular a solar park and/or a wind turbine and/or a wind farm, in particular an offshore wind farm. Alternatively and/or additionally, it is possible according to the invention that the current originating in particular from at least one of the aforementioned energy conversion systems is used to supply a self-contained or encapsulated medium-voltage and/or high-voltage network. In particular, direct currents originating from renewable energies can be used to supply consumers. In particular, the electricity generated in the aforementioned systems is direct current, which preferably does not have to be converted into alternating current before it is fed into the grid.

The fuse housing of the fuse is preferably designed in the form of a hollow cylinder and/or tubular. The top and bottom of the fuse housing is in particular designed to be open, at least in certain areas.

At the front, the fuse housing can be closed, preferably firmly, by the contact cap. Alternatively or additionally, it can be provided that the contact cap is placed on the fuse housing at the front. In particular, the contact cap is used for electrical contacting, with the fusible conductor being electrically connected to the contact cap.

In particular, the contact cap can have a diameter of between 30 and 100 mm, preferably between 50 and 90 mm. Provision is preferably made for the contact cap to have a standardized, preferably DIN standardized, diameter; in particular, the contact cap can have a diameter of 53 mm +/-5%, 67 mm +/-5% or 85 mm +/-5%.

At least one contact cap preferably covers at least a partial area of the fuse housing, in particular a partial area of the lateral surface in the front area. A fixed arrangement of the contact cap on the fuse housing can be ensured by the overlapping in some areas in the front area of the fuse housing.

According to a further preferred embodiment, another upper cap is arranged in front of the contact cap, which is placed on the contact cap and/or at least partially covers the contact cap. The inner contact cap can be designed as an auxiliary cap. Due to the two-part design of the contact cap a reliable electrical contact can be achieved, which is particularly advantageous in long-term use. Furthermore, this embodiment enables a particularly firm attachment or arrangement of the contact cap to the fuse housing.

In a further embodiment according to the invention, it is provided that the fuse housing has and/or consists of a ceramic material. Ceramic material is to be understood in particular as meaning a large number of inorganic, non-metallic materials, which can preferably be divided into the types of earthenware, earthenware, stoneware, porcelain and/or special materials. Electroceramics and/or high-temperature special masses are preferably provided as special ceramic masses.

Alternatively or additionally, it can be provided that the fuse housing has and/or consists of a material made of plastic, preferably melamine, and/or a glass fiber reinforced plastic.

An extinguishing agent, in particular an extinguishing sand filling, preferably quartz sand, and/or air can be provided in the fuse housing. When the fuse is switched, in particular in the event of a short circuit, the extinguishing agent is used to extinguish an arc and/or to cool down the possibly melted fusible conductor or the remains of the fusible conductor.

The fusible conductor can be at least partially embedded in the extinguishing agent or surrounded by the extinguishing agent, so that the extinguishing agent can act on the fusible conductor, in particular when the fusible conductor melts.

In a further preferred embodiment, the fuse housing is at least essentially hermetically encapsulated. Hermetic encapsulation or sealing is to be understood as meaning an airtight and/or gas-tight seal of the system, in particular one protected against water and/or liquids.

According to a further embodiment of the invention, it is provided that the fusible conductors are electrically connected in parallel and/or are wound at least essentially helically around the winding body. The parallel electrical connection of the fusible conductors is advantageous with a plurality of fusible conductors in the event of a short circuit or the triggering of the fuse, since the triggering of only one Fuse element is sufficient for switching. Due to the helical winding of the fusible conductor, the length of the fusible conductor required for the fuse can be enclosed in the fuse housing.

The winding body can be formed in one piece or from several elements. In particular, the winding body has and/or consists of hard porcelain as the material. In addition, the winding body can be designed in such a way that a plurality of chambers are formed, in particular in which case a cross-sectional constriction can be provided in one chamber. Due to the constricted cross-section, a large number of partial arcs can occur on each fusible conductor when the fuse responds, so that the amount of heat converted during the opening process can be distributed evenly over the entire length of the fuse tube.

In a further, very particularly preferred embodiment, it is provided that the fuse has a triggering device. The triggering device can be configured to switch a device arranged on the fuse, in particular a transformer switch and/or a load switch, preferably with trip-free release, and/or can be arranged in a contact cap. In particular, the triggering device has a firing pin triggering mechanism. When the firing pin release mechanism is triggered, it is provided that the firing pin, which is in particular at least essentially cylindrical, pierces through the contact cap, preferably a tightly soldered copper foil and/or a breakdown layer, in particular a paper sticker layer.

The firing pin of the firing pin triggering mechanism of the triggering device can be triggered by an auxiliary fuse element. In particular, the firing pin is triggered in the event of a short circuit.

A prestressed spring is preferably assigned to the firing pin, the spring being able to be designed in such a way that when the auxiliary fuse element is triggered, in particular in the event of a short circuit, the firing pin emerges from the end face of one of the contact caps. In particular, the firing pin can act on a load switch, which can then switch off the faulty current on all poles.

Provision is particularly preferably made for the auxiliary fusible conductor to run over the entire length of the fuse housing and/or axially through the center of the winding body runs. Accordingly, in particular, the auxiliary fuse element does not have to be wound around the winding body.

In addition, the auxiliary fusible conductor can be connected in parallel to the fusible conductor and/or the fusible conductors, in particular so that when a fusible conductor melts, a current flows through the auxiliary fusible conductor, which leads to activation of the firing pin.

A safety device can preferably be assigned to the triggering device, which is designed in such a way that after the trigger pin has been triggered, it can no longer be pressed and/or displaced into the fuse housing. Accordingly, if the firing pin is triggered, the safety device prevents the firing pin from being able to resume the position it was in before it was released. In this way, the load switch to be arranged on the firing pin can be permanently actuated by the firing pin in the event of a short circuit—in particular as long as the direct current is to be capped or switched off.

At least one display device can be assigned to the fuse. In particular, the display device is designed for the optical display of a state. The display device can also be arranged in the contact cap. Furthermore, the display device can be used as an alternative to the firing pin triggering mechanism and display the triggering of the fuse by means of an optical and/or acoustic signal. Ultimately, the display device is used to inform the operating personnel that the HH fuse has tripped.

According to a further embodiment it is provided that the contact caps have a galvanic coating and/or a silver coating. The contact caps can have and/or consist of electrolytic copper and/or aluminum as the material. The aforementioned materials enable good electrical contact.

Furthermore, the invention relates in particular to a system with a consumer that can be supplied with direct current and with at least one fuse that has the fusible conductor according to the invention and is designed according to at least one of the previously described embodiments. To the customer Transmit direct current, whereby the direct current can be secured by the fuse. In this case, a consumer is preferably provided as the recipient.

In order to avoid unnecessary repetitions, reference is made to the previous explanations with regard to the fusible conductor according to the invention and the fuse according to the invention, which also apply in the same way to the system according to the invention. Ultimately, it goes without saying that the advantages and preferred embodiments of the fuse according to the invention and/or the fuse element according to the invention that have already been presented can be transferred to the system according to the invention.

According to a very particularly preferred embodiment, it is provided that the consumer, which in particular can also be formed from a plurality of consumers, has a (total) power of more than 5 kW, preferably more than 50 kW, more preferably more than 700 kW and/or or a (total) output of less than 3000 MW, preferably less than 2000 MW, more preferably less than 1000 MW. Furthermore, alternatively or additionally, the output of the consumer can be between 50 kW and 3000 MW, preferably between 50 kW and 2000 MW, more preferably between 700 kW and 1000 MW. Consequently, customers with a high output can also be supplied by the direct current distribution network, which is protected by at least one fuse according to the invention.

Furthermore, it is understood that the aforementioned intervals and range limits contain any intermediate intervals and individual values contained therein and are to be regarded as disclosed as essential to the invention, even if these intermediate intervals and individual values are not specifically specified.

Further features, advantages and possible applications of the present invention result from the following description of exemplary embodiments with reference to the drawing and the drawing itself Summary in the claims and their reference.

Fig. 1

eine schematische Ansicht eines erfindungsgemäßen Schmelzleiters,

Fig. 2

eine schematische perspektivische Darstellung einer erfindungsgemäßen Sicherung,

Fig. 3

eine schematische Querschnittsdarstellung einer weiteren Ausführungsform einer erfindungsgemäßen Sicherung,

Fig. 4

eine schematische perspektivische Darstellung eines um einen Wickelkörper gewickelten erfindungsgemäßen Schmelzleiter,

Fig. 5

eine schematische Querschnittsdarstellung einer weiteren Ausführungsform einer erfindungsgemäßen Sicherung,

Fig. 6a

eine schematische perspektivische Darstellung einer weiteren Ausführungsform eines erfindungsgemäßen Schmelzleiters,

Fig. 6b

eine schematische Querschnittsdarstellung längs des Schnittes A-A aus Fig. 6a,

Fig. 6c

eine schematische Querschnittsdarstellung längs des Schnittes B-B aus Fig. 6a,

Fig. 7

eine schematische Prinzipdarstellung einer Verwendung einer erfindungsgemäßen Sicherung zur Sicherung einer Gleichstromübertragung und

Fig. 8

eine schematische Prinzipdarstellung einer weiteren Ausführungsform einer Verwendung einer erfindungsgemäßen Sicherung zur Sicherung der Gleichstromübertragung.

It shows:

1

a schematic view of a fuse element according to the invention,

2

a schematic perspective view of a fuse according to the invention,

3

a schematic cross-sectional view of a further embodiment of a fuse according to the invention,

4

a schematic perspective representation of a fusible conductor according to the invention wound around a winding body,

figure 5

a schematic cross-sectional view of a further embodiment of a fuse according to the invention,

Figure 6a

a schematic perspective representation of a further embodiment of a fuse element according to the invention,

Figure 6b

a schematic cross-sectional representation along the section AA Figure 6a ,

Figure 6c

a schematic cross-sectional representation along the section BB Figure 6a ,

7

a schematic representation of a use of a fuse according to the invention for securing a direct current transmission and

8

a schematic representation of a further embodiment of a use of a fuse according to the invention for securing the direct current transmission.

1 shows a fusible conductor 1. The fusible conductor 1 is as shown in FIG 3 as can be seen, for use for a DC fuse 2, in particular a high-voltage, high-performance direct current fuse 2 (HH-DC fuse). The fuse 2 can be provided for securing a direct current application, as is shown schematically in FIGS Figures 7 and 8 is shown.

1 FIG. 1 further shows that the fusible conductor 1 has an electrically conductive fusible wire 3 . The fusible wire 3 has at least two overload constrictions 4 designed as cross-sectional constrictions. In a first section 5--at least once on the fuse wire 3--a first layer 7 comprising and/or consisting of solder is provided, surrounding the outer jacket surface 6 of the fuse wire 3 at least in regions, preferably completely.

The first layer 7 or the first section 5 can be arranged at least once on the outer surface 6 of the fuse wire 3, in particular in the central region of the fuse wire 3.

Furthermore shows 1 that adjacent to each of the overload bottlenecks 4 in a respective second section 8 there is a second layer 9 surrounding the outer surface 6 of the fusible wire 3 circumferentially at least in regions, preferably completely.

The overload constrictions 4 are arranged one after the other in the longitudinal direction L of the fusible wire 3 .

in the in 1 The exemplary embodiment illustrated provides that the first section 5 is provided between the two immediately consecutive overload constrictions 4 . The first layer 7 does not have to be arranged in the middle between the two overload constrictions 4, but can do so in other embodiments.

In addition, 1 shown that the fusible wire 3 has at least one short-circuit constriction 10 designed as a cross-sectional constriction between two immediately consecutive overload constrictions 4. In the exemplary embodiment shown, the minimum width 11 and the shape of the cross-sectional constriction of the overload constriction 4 differ from the minimum width 12 and the shape of the cross-sectional constriction of the short-circuit constriction 10. The minimum widths 11, 12 of the cross-sectional constrictions ultimately indicate the smallest width in the area of a cross-sectional constriction. The short-circuit bottleneck 10 has different widths, for example in the area of the cross-sectional constriction.

Depending on the shape and the minimum width 11, 12 of the narrowing of the cross section, the response behavior of the fusible conductor 1 in the event of a trigger can be set accordingly—for overload protection.

At the in 1 The exemplary embodiment illustrated provides that the minimum width 11 of the cross-sectional constriction of the overload constriction 4 is greater than the minimum width 12 of the cross-sectional constriction of the short-circuit constriction 10 . The ratio of the minimum width 11 of the cross-sectional constriction of the overload constriction 4 to the minimum width 12 of the cross-sectional constriction of the short-circuit constriction 10 can be between 1.15:1 and 1.5:1. In other embodiments, the aforesaid ratio may be between 1.01:1 to 3:1.

What is not shown is that the shape of the cross-sectional constriction and/or the minimum width 11 of the overload constriction 4 is at least essentially the same or structurally identical to the shape of the cross-sectional constriction and/or the minimum width 11 of the short-circuit constriction 10 .

1 shows that the second layer 9 is directly adjacent to the congestion point 4. In addition, shows 1 that the second layer 9 is firmly, preferably cohesively and/or glued, connected to the outer lateral surface 6 of the fusible wire 3 or adheres to it.

What is not shown is that the second layer 9 has and/or consists of a plastic and/or poly(organo)siloxane as a material, preferably as an arc extinguishing agent. In further embodiments, the second layer 9 can consist at least essentially of silicone. The second layer 9 can alternatively or additionally be designed to be electrically insulating.

figure 5 shows that the second layer 9 is at least essentially directly adjacent to the cross-sectional narrowing of the overload constriction 4, but does not protrude or penetrate into the area of the cross-sectional narrowing of the overload constriction 4.

It is also not shown that the solder of the first layer 7 has and/or consists of a metal alloy as the material. In further embodiments, the metal alloy can contain and/or consist of cadmium, lead, tin, zinc, silver and/or copper. Furthermore, a metal alloy containing tin and/or silver may be provided. The first layer 7 can be designed to be electrically conductive.

In addition, shows 1 that a plurality of short-circuit bottlenecks 10 between two consecutive overload bottlenecks 4 - seen in the longitudinal direction L - is provided. In the exemplary embodiment shown, three short-circuit bottlenecks 10 are provided between two overload bottlenecks 4 . In further embodiments, between two to 15 short-circuit bottlenecks 10 can be provided between two immediately consecutive overload bottlenecks 4 .

Furthermore shows 1 that the first layer 7 or the first section 5, which has the first layer 7, is arranged between two directly consecutive short-circuit constrictions 10 on the outer lateral surface 6 of the fusible wire 3. The first section 5 can - but does not have to - be provided at least essentially in the middle between two short-circuit bottlenecks 10 .

In addition, 1 shown that the second sections 8 having the second layer 9 are arranged on the outer lateral surface 6 of the fusible wire 3 in such a way that between two directly consecutive second sections 8 or second layers 9 - running in the longitudinal direction L - the two overload constrictions 4 and in the illustrated embodiment, the short-circuit constrictions 10 arranged between the overload constrictions 4 are provided. Ultimately, the second sections 8 "enclose" or "frame" the two directly consecutive overload constrictions 4 and the short-circuit constrictions 10 arranged between them.

the 1 and 6a show that the overload constriction 4 is formed by a recess 13 having an at least substantially rectangular edge. The recesses 13 can be produced by punching, in particular by means of rectangular stamps.

Furthermore, in 1 shown that the corner or the corner area of the recess 13 has a rounding. A cross-sectional constriction of the overload bottleneck 4 having an at least substantially rectangular cross-sectional shape can be formed by the recesses 13 having at least substantially the rectangular edge.

Based on the detailed representation of the short-circuit constriction 10 in 1 It is clearly evident that the short-circuit bottleneck 10 is formed by a recess 14 having an edge that is at least essentially in the shape of a circular arc segment. The recesses 14 can be produced by punching. In particular, the narrowing of the cross section of the short-circuit constriction 10 and/or the overload constriction 4 is at least essentially mirror-symmetrical—in particular in relation to the central axis of the fusible wire 3.

Figure 6a shows that the cross-sectional constriction of the short-circuit constriction 10 has an at least essentially circular-arc segment-shaped contour—in the top view of the fusible wire 3 . The contour of the cross-sectional constriction of the overload constriction 4 can be straight, with rounded corners or curves being provided in particular in the corner regions of the cross-sectional constriction of the overload constriction 4 .

In the 1 short-circuit bottlenecks 10 shown are between the overload bottlenecks 4--seen in the longitudinal direction L--at least essentially regularly spaced. In particular, the short-circuit bottlenecks 10 are at least essentially the same distance 15 from one another. In further embodiments, the distance 15 can be between 5 and 30 mm, in particular between 10 and 20 mm.

In 1 is further shown that the distance 16 between a short-circuit constriction 10 to the immediately adjacent overload constriction 4 is at least substantially the same. The distance 16 always results between the cross-sectional constriction of the overload constriction 4 to the next cross-sectional constriction, namely the cross-sectional constriction of the short-circuit constriction 10. This distance 16 is in particular of the same design. The distance 16 can correspond to the distance 15 in further embodiments.

In addition, the distance 17 between a cross-sectional constriction of the short-circuit constriction 10 and/or overload constriction 4 to the immediately adjacent cross-sectional constriction of the short-circuit constriction 10 and/or overload constriction 4 can be at least substantially the same. The distance 17 can be designed both as a distance 15 and as a distance 16 .

The distance 17 can also be independent of the short-circuit bottleneck 10, namely in embodiments in which no short-circuit bottleneck is provided, and/or independently of the plurality of short-circuit bottlenecks 10, namely in embodiments in which only a single short-circuit bottleneck 10 is provided between two immediately adjacent overload bottlenecks 4 , be formed at least substantially the same. The distance 17 ultimately indicates the distance between two immediately adjacent cross-sectional constrictions--seen in the longitudinal direction L of the fuse wire 3--where the cross-sectional constriction can be formed both by a short-circuit constriction 10 and by an overload constriction 4. Ultimately, the cross-sectional constrictions on the fusible wire 3 are particularly regularly spaced.

The distance between two immediately adjacent overload constrictions 4 can be between 50 and 80 mm, in particular between 60 and 70 mm.

in the in 1 The exemplary embodiment illustrated provides that the length 18 of the cross-sectional constriction of the overload constriction 4 is greater than the length 19 of the cross-sectional constriction of the short-circuit constriction 10 . Ultimately, the narrowing of the cross section of the overload constriction 4 can be at least essentially elongate. The length 18 of the narrowing of the cross section of the overload constriction 4 can be between 1 and 3 mm and in particular can be 2 mm ± 0.5 mm. The length 19 of the cross-sectional constriction of the short-circuit constriction 10 can be 1.5±0.5 mm.

In further embodiments, the first and/or the second layer 7, 9 can be formed as a coating.

In 1 It is shown that the first layer 7 in the first section 5 is applied to the top of the fusing wire at least essentially with a circular shape—seen in cross section.

The second layer 9 can be applied at least essentially in the form of a ring, encasing or surrounding the fuse wire 3 on the outer lateral surface 6 of the fuse wire 3 .

the Figures 6b and 6c show the cross sections of a further embodiment of the fuse element 1, with both the first layer 7 and the second layer 9 in their respective sections 5 and 8 have been applied at least essentially completely encasing or surrounding the outer lateral surface 6 of the fuse wire 3 .

Figure 6a shows that the fuse wire 3 has an at least substantially rectangular cross-sectional shape. In the illustrated embodiment, the fusible wire 3 is designed as a flat strip, which can have a plurality of cross-sectional constrictions. The fusible wire 3 can have a strip thickness or height of 0.04±0.01 mm when it is designed as a flat strip. The maximum width 10 of the fuse wire 3 can be 1.5±0.5 mm.

In Figure 6a is shown in perspective how the recesses 13, 14 form the cross-sectional constrictions of the overload constriction 4 and the short-circuit constriction 10.

In further embodiments, it can alternatively be provided that the fuse wire 3, the first and/or the second layer 7, 9 have an at least essentially circular outer cross section.

What is not shown is that the fusible wire 3 has metal as the material. At least essentially pure silver can be provided as the metal. In particular, the silver has a purity of 99.99%. The aforesaid degree of purity indicates the content of Ag (silver) in the metal material. This is also referred to as fine silver.

In a further embodiment it can be provided that the fusible wire 3 has and/or consists of copper and/or a copper alloy as the material.

From the Figures 3 and 4 It can be seen schematically that the fusible conductor 1 has an alternating sequence of overload constrictions 4 directly following one another. In particular, a sequential sequence of the overload constrictions 4 and in particular of the short-circuit constrictions 10 arranged between the overload constrictions 4 is provided. In the alternating sequence of the overload bottlenecks 4 , an at least essentially structurally identical configuration of two immediately consecutive overload bottlenecks 4 and in particular of the short-circuit bottlenecks 10 provided between the overload bottlenecks 4 is provided. The overload bottlenecks 4 are in the in 3 illustrated embodiment at least substantially regularly spaced and have at least substantially the same distance from each other. This in 1 The "pattern" shown of the cross-sectional constrictions arranged between two second sections 8 and the respective shape of the cross-sectional constrictions corresponding thereto is thus provided in particular repeatedly along the longitudinal direction L of the fusible wire 3 .

In particular, the first section 5 is not repeated, so that the fusible conductor 1 as a whole has only at least one first layer 7; in particular independently of the number of overload bottlenecks 4. However, the second layer 9 is in particular provided adjacent to each overload bottleneck 4.

At the in 1 In the exemplary embodiment illustrated, it is provided that the ratio of the maximum width 20 of the fuse wire 3 to the minimum width 11, 12 of the cross-sectional constriction of the overload constriction 4 and/or the cross-sectional constriction of the short-circuit constriction 10 is between 1:0.4 to 1:0.35. In further embodiments, the aforementioned ratio can be between 1:0.6 to 1:0.2 and can have any value within the specified interval.

In 2 a fuse 2 for securing a DC application is shown. In particular, an HH-DC fuse 2 is provided. The fuse 2 has an outer fuse housing 21, with at least one fusible conductor 1 wound around an, in particular electrically insulating, winding body 22 being arranged in the fuse housing 21 according to at least one of the previously described embodiments.

What is not shown is that a plurality of fusible conductors 1 can also be wound around the winding body 22 . The fusible conductor 1 has a plurality of cross-sectional constrictions, with the formation of the cross-sectional constrictions of the short-circuit bottlenecks 10 and the overload bottlenecks 4 in combination with the first and second layers 7, 9 making it possible to use the fuse 2 as an HH-DC fuse 2 in the first place.

2 FIG. 1 further shows that at least one contact cap 24 designed for electrical contacting is arranged on the end face of the fuse housing 21 .

the Figures 7 and 8 show that fuse 2 can be used to secure a direct current transmission, where in 7 the fuse 2 is arranged between a direct current source 27 and a consumer 29 . The direct current transmitted to the pickup 29 flows through the fuse 2.

What is not shown is that the fuse housing 21 is designed to be at least essentially open on the two end faces 23 .

the 3 and 5 show that the winding body 22 is formed at least substantially in a star shape. The star-shaped configuration of the bobbin 22 is also good figure 5 evident. The winding body 22 has—seen in cross section—projections 25 or webs, with recesses or depressions 26 being provided between the projections 25 or webs. The projections 25 are designed in such a way that they can be used to support the fusible conductor 1 at least essentially at certain points. The fusible conductor 1 does not lie on the surface of the winding body 22 between the projections 25 .

At the in the Figures 7 and 8 illustrated embodiments, the DC voltage of the direct current is greater than 1 kV and less than 100 kV. In further embodiments, the DC voltage can be between 1.5 kV to 50 kV or between 3 kV to 30 kV. In further embodiments, the rated voltage or the rated voltage range of the fuse 2 is greater than 1 kV and/or less than 100 kV and/or is between 1 kV and 100 kV, preferably between 1.5 kV and 50 kV.

Furthermore, when in the Figures 7 and 8 Fuse 2 used in a direct current network is such that the smallest breaking current of the fuse 2 is 50 A ± 20 A. In further embodiments, the smallest breaking current of the fuse 2 can be greater than 3 A and/or less than 500 A and/or between 3 A and 700 A, preferably between 5 A and 500 A.

In further embodiments, the smallest breaking current of the fuse 2 can correspond to 1.5 times to 10 times the rated current intensity, in particular the minimum or smallest breaking current being directly dependent on the rated current intensity of the respective fuse link.

The rated switching capacity or the maximum breaking current of the fuse 2 is in the exemplary embodiment shown in FIG Figures 7 and 8 greater than 1 kA and/or is between 20 kA and 50 kA.

The in the Figures 7 and 8 The direct current source 27 shown provides direct current with a current greater than 5 A. In particular, the amperage of the direct current and/or the rated amperage range is between 10 A and 75 kA.

Depending on the transmitted direct current and the direct current voltage, the product of the direct current secured by the fuse 2 and the direct current voltage can vary. in the in Figures 7 and 8 illustrated embodiment gene is the aforementioned product 1000 kW ± 50 kW. In further embodiments, the product (mathematical multiplication) of the direct current secured by the fuse 2 and the direct voltage can be between 5 kW and 3000 MW, in particular between 700 kW and 1000 MW.

What is not shown is that a plurality of fusible conductors 1 are arranged in the fuse housing 3 . In further embodiments it can be provided that between 2 and 10 fusible conductors 1 are used.

What is not shown is that the direct current application is a medium-voltage direct current application and/or a high-voltage direct current application. The medium-voltage direct current application has a direct voltage of up to 30 kV. A high voltage DC application has a DC voltage of over 50 kV.

The fuse 2 can also be arranged on a medium-voltage direct current network, in particular in a medium-voltage direct current system with at least one MVDC device.

Furthermore, it is not shown that the direct current source 27 is a photovoltaic system and/or photovoltaic area system (ie a solar park) and/or a wind power plant and/or a wind park, in particular an offshore wind park. In particular, the aforementioned energy conversion systems make direct current available to the direct current network. The through the aforesaid energy conversion plants The electricity generated can be transmitted to the consumer 29 secured by at least one fuse 2.

About it is in the Figures 7 and 8 a system 28 with a collector 29 that can be supplied by direct current is shown. In particular, the buyer 29 is a consumer or a plurality of consumers. Furthermore, the system 28 has a fuse 2 which is designed to secure the direct current transmitted to the customer 29 . What is not shown is that the output of the consumer 29 is greater than 5 KW and less than 2000 MW. In particular, the fuse 2 is used in a DC network.

2 shows that the fuse housing 21 is designed in the form of a hollow cylinder or tube. At the front, the fuse housing 21 is tightly closed by the contact caps 24 , it being possible for the contact cap 24 to be placed on the fuse housing 21 .

In 2 it is shown that the contact cap 24 covers at least a partial area of the lateral surface in the front area of the fuse housing 21 .

What is not shown is that the contact cap 24 is assigned a further upper cap, which is placed in front of the contact cap 24 and at least partially covers the contact cap 24 . In this case, the contact cap 24 represents the so-called inner auxiliary cap.

This in 2 Fuse housing 21 shown has a ceramic material. In further embodiments, the fuse housing 21 can consist of a ceramic material. As an alternative or in addition, the fuse housing 21 can have a plastic, in particular a glass-fiber-reinforced plastic, as the material.

What is not shown is that an extinguishing agent is provided in the fuse housing 21 . An extinguishing sand filling, preferably quartz sand, and/or air can be used as the extinguishing agent.

4 shows that the fusible conductor 1 is electrically connected to the contact cap 24.

What is not shown is that the fusible conductor 1 is at least partially, in particular completely, embedded in the extinguishing agent or surrounded by the extinguishing agent. The fusible conductor 1 has in particular an arc extinguishing agent due to the formation of the second layer 9 or due to the material of the second layer 9 .

In addition, it is not shown that the fuse housing 21 is at least essentially hermetically encapsulated.

Hard porcelain can be provided as the material for the winding body 22 .

In further embodiments, the winding body 22 can be designed in such a way that a plurality of chambers is formed, in particular with a cross-sectional constriction being provided in one chamber.

Also not shown is that the contact cap 24 has a galvanic coating and/or a silver coating and/or has and/or consists of electrolytic copper and/or aluminum as the material.

Reference list:

1

fusible conductor

2

fuse

3

fusible wire

4

overload point

5

first section

6

outer surface of 3

7

first layer

8th

second part

9

second layer

10

short-circuit bottleneck

11

Minimum width of 4

12

Minimum width of 10

13

recess of 4

14

recess of 10

15

Distance between two short circuit bottlenecks

16

Distance between short-circuit bottleneck and overload bottleneck

17

Distance between cross-section constrictions

18

length of 4

19

length of 10

20

Maximum width of 3

21

outer fuse box

22

winding body

23

face

24

contact cap

25

lead of 22

26

deepening of 22

27

direct current source

28

system

29

customer

L

longitudinal direction

Claims (15)

1. Use of a fusible conductor (1) for a DC fuse (2) and a high-voltage high-capacity fuse (2) (HH-DC fuse), wherein the fusible conductor (1) has an electrically conductive fusible wire (3), wherein the fusible wire (3) has at least two overload points (4) in the form of a cross-sectional constriction, wherein, preferably between the two directly successive overload points (4), in at least one first section (5) a first layer (7) is provided which comprises solder and/or consists thereof and circumferentially surrounds the outer circumferential surface (6) of the fusible wire (3) at least in regions, preferably completely, characterised in that adjacent to each of the overload points (4) in a respective second section (8), a second layer (9) is provided which circumferentially surrounds the outer circumferential surface (6) of the fusible wire (3) at least in regions, preferably completely, and
   wherein the fusible wire (3) has at least one short-circuit constriction (10) in the form of a cross-sectional constriction between two directly successive overload points (4).
2. Use according to claim 1, characterised in that the minimum width (11) and/or the shape of the cross-sectional constriction of the overload point (4) differs from the minimum width (12) and/or the shape of the cross-sectional constriction of the short-circuit constriction (10) and/or
   that the minimum width (11) of the cross-sectional constriction of the overload point (4) is greater than the minimum width (12) of the cross-sectional constriction of the short-circuit constriction (10), in particular wherein the ratio of the minimum width (11) of the cross-sectional constriction of the overload point (4) to the minimum width (12) of the cross-sectional constriction of the short-circuit constriction (10) is between 1.01:1 to 3:1, preferably between 1.1:1 to 2:1, further preferably between 1.15:1 to 1.5:1.
3. Use according to one of the preceding claims, characterised in that the second layer (9) is at least substantially directly adjacent to the overload point (4) and/or in that the second layer (9) is firmly, preferably materially, connected to the outer circumferential surface (6) of the fusible wire (3).
4. Use according to one of the preceding claims, characterised in that a plurality of short-circuit constrictions (10) is provided between two directly successive overload points (4), in particular wherein between 2 to 15, preferably between 3 to 6, short-circuit constrictions (10) are provided between two overload points (4) and/or wherein the first section (5) comprising the first layer (7) is arranged between two directly successive short-circuit constrictions (10) on the outer circumferential surface (6) of the fusible wire (3).
5. Use according to one of the preceding claims, characterised in that the second sections (8) comprising the second layer (9) are arranged on the outer circumferential surface (6) of the fusible wire (3) in such a way that between two directly successive second sections (8) and/or second layers (9) the two overload points (4) and preferably the short-circuit constriction (10) arranged between the overload points (4) and/or the short-circuit constrictions (10) are provided.
6. Use according to one of the preceding claims, characterised in that the overload point (4) is formed by recesses (13) having an at least substantially rectangular edge and/or
   in that the short-circuit constriction (10) is formed by recesses (14) having an at least substantially arc-shaped edge.
7. Use according to one of the preceding claims, characterised in that the short-circuit constrictions (10) arranged between the overload points (4) are at least substantially regularly spaced apart and/or in that the distance (15) between two directly adjacent short-circuit constrictions (10) and/or the distance (16) between a short-circuit constriction (10) to the directly adjacent overload point (4) is at least substantially the same and/or in that the distance (17) between a cross-sectional constriction of the short-circuit constriction (10) and/or the overload point (4) to the immediately adjacent cross-sectional constriction of the short-circuit constriction (10) and/or the overload point (4) is at least substantially the same.
8. Use according to one of the preceding claims, characterised in that the length (18) of the cross-sectional constriction of the overload point (4) is greater than the length (19) of the cross-sectional constriction of the short-circuit constriction (10).
9. Use according to one of the preceding claims, characterised in that the fusible conductor (1) has an alternating sequence of directly successive overload points (4), preferably with short-circuit constrictions (10) arranged between two directly successive overload points (4), in particular wherein the overload points (4) are at least substantially regularly spaced.
10. HH-DC fuse (2) for securing a direct current transmission, having an outer fuse housing (21), wherein in the fuse housing (21) at least one fusible conductor (1) is arranged, wound around a, in particular electrically insulating, winding body (22) and having the constructive features of at least one of the preceding claims.
11. HH-DC fuse according to claim 10, characterised in that the fuse housing (21) is designed to be at least partially open on two end faces (23), wherein at least one contact cap (24) is arranged in each case on the end face of the fuse housing (21) designed for electrical contacting.
12. HH-DC fuse according to claim 10 or 11, characterised in that the DC voltage of the DC current and/or the rated voltage of the fuse (2) is greater than 1 kV, preferably greater than 1.5 kV, more preferably greater than 5 kV, and/or is less than 150 kV, preferably less than 100 kV, more preferably less than 75 kV, and/or is between 1 kV and 100 kV, preferably from 1.5 kV to 50 kV, more preferably from 3 kV to 30 kV.
13. HH-DC fuse according to any one of the preceding claims 10 to 12, characterised in that the transmitted DC current and/or the rated current range is greater than 5 A, preferably greater than 10 A, more preferably greater than 15 A, and/or is between 3 A to 100 kA, preferably between 10 A to 75 kA, more preferably between 15 A to 50 kA.
14. HH-DC fuse according to any one of the preceding claims 10 to 13, characterised in that the product of the DC current and the DC voltage protected by the fuse (2) is greater than 5 kW, preferably greater than 50 kW, more preferably greater than 700 kW, and/or is less than 3000 MW, preferably less than 2000 MW, more preferably less than 1000 MW, and/or is between 5 kW and 3000 MW, preferably between 500 kW and 2000 MW, more preferably between 700 kW and 1000 MW.
15. System (28) with a consumer (29), which can be supplied by direct current, in particular an user, with at least one fuse (2) according to at least one of claims 10 to 14, wherein the direct current transmitted to the consumer (29) can be protected by the fuse (2), in particular wherein the power of the consumer (8) is greater than 5 kW, preferably greater than 50 kW, more preferably greater than 700 kW, and/or is less than 3000 MW, preferably less than 2000 MW, more preferably less than 1000 MW, and/or is between 50 kW and 3000 MW, preferably between 50 kW and 2000 MW, more preferably between 700 kW and 1000 MW.

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