EP3830858A1

EP3830858A1 - Fusible conductor, and fuse

Info

Publication number: EP3830858A1
Application number: EP20728374.8A
Authority: EP
Inventors: Dirk Wilhelm; Jens Weber; Johannes-Georg GÖDEKE
Original assignee: Siba Fuses GmbH
Current assignee: Siba Fuses GmbH
Priority date: 2019-06-25
Filing date: 2020-05-18
Publication date: 2021-06-09
Anticipated expiration: 2040-05-18
Also published as: DE102019005664A1; CN114787955A; US11710613B2; DK3830858T3; US20220068581A1; PT3830858T; CN114787955B; KR20210105877A; WO2020259924A1; EP3830858B1; SI3830858T1; HUE059119T2; ES2920968T3; PL3830858T3

Abstract

The invention relates to the use of a fusible conductor (1) for a DC fuse (2) and a high-voltage, high-power fuse (2) (HH-DC fuse), the fusible conductor (1) having an electrically conductive fuse wire (3), the fuse wire (3) having at least two overload constriction points (4) designed as cross-sectional constrictions. Preferably, between the two immediately consecutive overload constriction points (4), in at least one first portion (5) a first layer (7) including solder and/or consisting thereof is provided which at least partially, preferably completely, surrounds the outer surface (6) of the fuse wire (3) circumferentially, and, adjoining each of the overload constriction points (4), in a second portion (8) a second layer (9) is provided which at least partially, preferably completely, surrounds the outer surface (6) of the fuse wire (3) circumferentially.

Description

Fusible link and fuse

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). The present invention also relates to a fuse for a direct current application.

The energy supply over the next few years and / or decades will be subject to a drastic structural change. This energy transition and in particular the German "energy turnaround" 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.

The generation of energy is increasingly decentralized, whereby this is under the influence of renewable energy systems (RE systems). Many renewable energy systems generate direct current that is then fed into an associated network, in particular into a distribution network.

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

Securing the direct current is not only necessary for distribution networks that are fed by renewable energy systems, but also for distribution networks that work with direct voltage. An alternating current transmission or an alternating current network is currently common on the market. However, this will change in the next few years to decades.

The reason for this is that direct current transmission for power transmission over comparatively long distances is preferred from a technical point of view with regard to reduced transmission loss. To connect offshore systems, a high-voltage direct current transmission connection (HVDC connection) and / or medium-voltage direct current transmission connection (MGÜ connection) are particularly suitable for power transmission. Such power transmission takes place at the transmission level. However, in order to connect the consumers and in particular the households, there is a handover from the transmission level to the distribution level. The distribution level, which provides the equal ström received from the transmission level must be permanently secured under high technical requirements.

A restructuring of the network from alternating voltage to direct voltage causes the challenge of securing the direct voltage on the distribution network level, so that the households and / or the electrical consumers and / or the energy systems, in particular the renewable energy systems, can be safely connected to the direct current distribution network can be connected.

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

One of the greatest challenges here is securing the direct current network or the direct current application. Without such a safeguard, the concepts for direct current transmission and in particular for decentralizing electricity generation and feeding in decentralized power plants or energy systems cannot be implemented. DC fuses for direct current use, especially on the distribution network level, are a technical anchor point for safe network operation.

However, it is disadvantageous in current direct current applications that in practice - if at all - only an inadequate or at most sufficient protection of the direct current transmission and / or the direct current application can be guaranteed. Particularly for a direct current application on the distribution network level, there are no known fuses that on the one hand can 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. As a result, 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.

But not only switching off in the event of a short circuit, but also switching off in the event of an overload (overload circuit) is necessary to ensure long-term protection of the DC application. Overload currents are currents that exceed the rated value of the consumer loads arranged in the direct current distribution network. mer, especially the equipment, a system, cables and / or lines, without a short circuit being present.

A fuse for a direct current high voltage which simultaneously enables overload and short-circuit protection is not known in the prior art. However, this would be necessary for safe operation of the direct current distribution network and the direct current transmission line. Without overload protection, the heating of the consumers to be protected, such as equipment, cables and / or lines, cannot be prevented in continuous operation. In the event of an overload and / or during a short circuit, the consumers are therefore 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. EP 3 270 403 A1 relates, for example, to such a low-voltage fuse for a DC voltage circuit.

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

According to the invention, the aforementioned object is achieved by using a fusible conductor for a DC fuse (a fuse for direct current transmission) and a high-voltage, high-performance fuse (the so-called HH-DC fuse). The fusible conductor has an electrically conductive fusible wire. The fuse wire has at least two overload constrictions designed as a cross-sectional constriction. In at least one first section, a first layer surrounding the outer jacket surface of the fusible wire at least in some areas, preferably completely, is provided. The first layer has solder as material and / or consists of it. The at least one first section is preferably provided between the two immediately successive transfer points. Adjacent to each of the overload constrictions, a second layer is provided in each case in a second section that surrounds the outer jacket surface of the fusible wire at least in certain areas, preferably completely. According to the invention, the fusible wire is not fixed or limited 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 in addition, it can be provided that the fuse wire is at least substantially cylindrical and / or has an at least substantially circular cross-sectional shape.

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

Particularly preferably, the overload constrictions are arranged one after the other in the longitudinal direction of the fuse wire. When used in a DC fuse, the fusible link 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 place for up to one hour.

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

Alternatively or in addition, 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 transfer points.

According to the invention it has been found that the minimum breaking current can be significantly reduced by the arrangement of the overload constrictions in combination with the first and second layers. This ultimately enables the fuse element to be used in FIFI DC fuses, which can be used both for short-circuit shutdown and for overload shutdown. The short-circuit protection can be made possible by the fuse in that the largest short-circuit currents can be safely interrupted at their installation point. The overload protection, in turn, can take place in a current-dependent manner through the first layer, whereby the breaking capacity for the overload protection can generally be smaller than the short-circuit current at the installation point of the fuse.

The use of further means for safeguarding a direct current application and in particular for ensuring overload protection can be avoided. Further switch disconnectors or the like are not required and / or such a need is reduced. According to the present invention, a direct current transmission network can be efficiently secured. 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 fuse element inserted 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 amperage onwards, the fuse is able to switch the overcurrent. Accordingly, the electrical components (consumer, direct current source, etc.) are to be arranged and / or designed on the fuse in such a way that no overcurrent can occur at the installation location of the fuse that falls below the smallest breaking current. The smallest breaking current can depend on the type of fuse selected.

In addition, the length of the fusible conductor required for an HVDC 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 HVDC fuse can depend in particular on the rated voltage of the fuse. The arrangement according to the invention can preferably reduce the length of the fusible conductor by at least 10%, preferably 20%, more preferably 30%.

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 "wide" current range. When the invention came about, it was surprisingly found that the inventive design of the fusible conductor means that the fuse having the fusible conductor is 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 has hitherto been known in the prior art which can secure a direct current application, in particular in the high-voltage, high-power range. Securing in the medium-voltage and / or high-voltage area in particular is linked to a large number of requirements and standards to be complied with. A high level of sensitivity and caution with regard to the potential danger resulting from high voltages or currents has meant that fuses have not been used "indiscriminately" or at all for the transmission and / or distribution of different types of current. In particular, there has not been an adequate solution for direct current transmission due to the expected problems.

If one of the consumers and / or consumers electrically connected to the direct current distribution network were to cause a short circuit and / or have an overload, the entire direct current network would fail - at least after a certain time. Even if there is no direct failure of the direct current network, high thermal and / or mechanical loads on the connected consumers and / or consumers cannot be prevented. Accordingly, fuses in direct current networks or direct current distribution and / or direct current transmission have been dispensed with in practice, since the fuse required for a stable and safe power network or direct voltage circuit could not be permanently guaranteed.

Surprisingly and unpredictably, however, it has been found according to the invention that the special fusible conductor according to the invention can be used in a HV HRC fuse and / or in a fuse for a direct current application, whereby the necessary safety can be guaranteed, especially in the event of an overload or short circuit. It was 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 combined with an escape of extinguishing agent and / or an arc leak, can be prevented. In simulated long-term tests it has been found that also with one 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 over five years, preferably over ten years, more preferably over 15 years, which, in particular legally prescribed, required safety guidelines and / or regulations can be observed. 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 (for example renewable energy systems) to the direct current connection or to the DC voltage circuit, which are secured by at least one fuse having the fusible conductor. If a consumer fails, especially in the event of a short circuit, the direct current network does not collapse. In this way, security of supply in particular can be guaranteed.

The direct current network can preferably be secured in sections by means of the fuse having the fusible conductor according to the invention.

The fuse having the fusible conductor is designed as a fuse through the fusible link. The fuse is an overcurrent protection device that interrupts the circuit by melting the fusible conductor if the current strength 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.

Basically, 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 oversizing - achieved according to the invention. In particular, the fusible conductor according to the invention is not technically necessary when used in a fuse for securing alternating current transmission. In relation to its length, the fusible conductor provides a relatively high resistance to the rest of the network, in particular the direct current distribution network, which in rated operation leads to heating and to melting in the event of overload or in the event of a short circuit.

By forming the cross-sectional constrictions in combination with the first and second layers, the behavior of the fusible conductor can be influenced in a manner according to the invention in such a way that the fusible conductor is suitable for securing direct current transmission, particularly in the high-voltage range.

The fusible conductor can also 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 area can advantageously be influenced by the overload constrictions. The overload constrictions are particularly preferably designed to be elongated, in particular by punching them out using angular punches, so that a faster or slower response can be set through the length of the cross-sectional constriction and the “web width” (width of the cross-sectional constriction).

The first layer can also only be applied circumferentially on the fusible wire or on the outer jacket surface of the fusible wire, in particular only on the upper and / or lower side 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 in the second section is preferably formed in such a way that it at least substantially completely surrounds the fusible wire (at least in the second section) circumferentially. The second layer can have an at least substantially ring-shaped and / or hollow-cylindrical shape. Preferably, the second layer and the second section directly adjoin the overload constriction, so that the overload constriction formed as a cross-sectional constriction is at least essentially immediately adjacent to the second section. The second section preferably extends each but not in the area of the overload constriction with the reduced cross-section.

In particular, the first section can be provided at least essentially centrally between the second sections and / or between the immediately successive 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 at least essentially in the center of the fusible conductor. In further embodiments, at least two first layers can be provided for each fusible conductor, wherein the first section having the first layer can be arranged independently of the cross-sectional constrictions and / or in the middle - viewed in the longitudinal direction of the fusible wire - on the fusible wire.

In a particularly preferred embodiment, it is provided that the fusible wire has at least one short-circuit constriction designed as a cross-sectional constriction between two immediately successive overload constrictions. The short-circuit bottleneck enables, in particular, the switching of the fuse having the fuse element according to the invention 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 substantially 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 design of the short-circuit constriction, a more nimble or less nimble short-circuit behavior can be set. The fleas of the forward current in the event of a short circuit are also reduced by the minimum width and / or the bottleneck width of the short-circuit bottleneck significantly adjustable.

According to the invention, it is preferably provided 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 enables the fuse having the fusible link to switch both in the event of a short circuit and in the event of an overload, since a different design of the cross-sectional constrictions of the short-circuit constriction and the overload constriction can ensure a corresponding fuse behavior for the short-circuit disconnection.

Ultimately, it goes without saying that the cross-sectional constriction of the overload constriction and / or the short-circuit constriction need not have a constant width. The minimum width of the cross-sectional constriction is to be understood as 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 to 3: 1, preferably between 1.1: 1 to 2: 1, more preferably between 1.15 to 1.5: 1. The aforementioned conditions ensure, in particular, that overcurrent protection is guaranteed 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 and 1.5 mm, preferably between 0.4 and 1 mm, more preferably between 0.5 and 0.7 mm and in particular at least substantially 0 , 6 mm.

The minimum width of the cross-sectional constriction 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 substantially 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 to say 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-circuit constriction and those of the overload constriction at least substantially correspond or are designed to be the same.

It is very particularly preferably provided that the cross-sectional constriction of the overload constriction and / or the short-circuit constriction is homogeneous, in particular over the length of the constriction. The cross-sectional constriction is preferably formed or produced by a punched-out section 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 at least substantially identical.

The second layer and / or the second section preferably adjoins the respective overload constriction at least essentially directly, in particular with the respective second layer being provided directly adjacent to each overload constriction. In particular, according to the invention, a direct abutment is also understood to mean that a small distance is provided between the second section and / or the second layer and the overload constriction, which is in particular less than or equal to the length of the respective overload constriction. Such an arrangement enables in particular that a very low minimum breaking current can be achieved.

In addition, in a further preferred embodiment of the inventive concept, 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 jacket surface of the fuse wire, in particular wherein the second layer has been dripped onto the outer jacket surface of the fuse wire. In particular, the second layer adheres to the outer jacket surface of the fuse wire.

In a further very 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 material, preferably as an arc extinguishing agent. Furthermore, the second layer can be designed to be electrically insulating. In particular, by combining the solder of the first layer with the silicone or the material of the second layer, the minimum switch-off current or the lowest switch-off current can be reduced. According to the invention, a significant increase in the rated voltage of the DC fuse in the event of a short circuit - assuming a given product of the direct current secured by the DC fuse and the direct voltage - can therefore be achieved by using the second layer on the fuse wire, which contains the silicone.

By using the solder in the first coating, the melting temperature of the fusible conductor can also be reduced to values where in particular the silicone is at least essentially undamaged in its "pure form". If the first layer had no solder, a fusible conductor temperature in the order of magnitude 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 achieved even in the event of an overload. In this case, there would be the risk that the material of the second layer - namely the silicone - can no longer serve as an extinguishing arc means or as an extinguishing medium.

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

When choosing the first layer, legal directives - such as the EU RoHS directive - that limit the use of hazardous substances in electronic devices must also be taken into account, in particular 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, ultimately occurs in the area of the second section, in particular in the area of the application of tin. 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 or material of the fuse wire, this alloy has a lower electrical and thermal conductivity and in particular a lower melting point. As a result of the increasing heat development, 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 fuse wire, a fuse can take advantage of the previously described M-effect to trigger the fuse.

Most preferably, a plurality of short-circuit bottlenecks is provided between two immediately successive overload constrictions. In particular, between 2 to 15, preferably between 3 to 6, short-circuit constrictions are provided between two immediately successive overload constrictions.

Alternatively or in addition, it can be provided that the first section having the first layer - at least once in the fusible conductor - is arranged between two immediately successive short-circuit constrictions, preferably in the middle between immediately successive short-circuit constrictions and / or in the middle between two immediately successive overload constrictions, on the outer jacket surface of the fuse wire is.

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

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

The second sections comprising and / or forming the second layer are preferably arranged on the outer jacket surface of the fusible wire in such a way that the two overload constrictions and preferably the short-circuit constriction and / or the short-circuit constrictions between two immediately successive second sections and / or second layers are provided. As a result, it is particularly preferable There is also an arrangement in the form of a second layer or second section - overload constriction - possibly at least one short-circuit constriction - overload constriction - second layer or second section.

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

Alternatively or in addition, 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 which have an at least substantially rectangular edge. In particular, the corners of the rectangular contour of the recesses can be designed to be at least substantially segment-shaped or rounded. The cutout can be punched out, for example, by means of an angular stamp.

The short-circuit constriction and / or the cross-sectional constriction of the short-circuit constriction is preferably formed by cutouts having an edge which is at least essentially in the form of a segment of a circular arc.

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

The cutout in the shape of a circular arc section can also be achieved by punching, preferably by means of a round punch. In particular, the short-circuit constriction and / or the overload constriction is designed as an at least essentially round short-circuit constriction and / or the overload constriction.

Preferably, at least two cutouts are provided for each cross-sectional constriction of the overload constriction and the short-circuit constriction. The recesses can be arranged opposite one another, in particular the two recesses for each cross-sectional constriction of the overload constriction and the short-circuit constriction are at least essentially the same and in particular which are arranged mirror-inverted to one another, wherein the recess can be mirrored along the central axis of the fuse wire.

Ultimately, the overload constrictions in the form of a cross-sectional constriction and / or the short-circuit constrictions in the form of a cross-sectional constriction can be constructed at least essentially identically.

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

For example, a circular arc section-shaped recess of the short-circuit constriction with at least substantially the same cross-sectional width and / or the same cross-sectional length can dissipate the heat better than an overload constriction with at least substantially rectangular recess, since the short-circuit constriction in particular contains "more material". In the case of a very high overload current, however, in particular the minimum width of the cross-sectional constriction is an extremely relevant parameter, in particular more relevant than the shape of the cross-sectional constriction, since the cross-sectional constriction initially melts in the middle and not homogeneously.

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

In the case of very high overcurrents - that is, in the event 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 that "takes" more cross-sectional constrictions into account. It is provided that the cross-sectional constrictions of the overload constrictions in the event of an overload due to the at least essentially rectangular shape of the cutouts will melt before the short-circuit constrictions. 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 substantially regularly spaced. Accordingly, the distance between two immediately successive short-circuit constrictions in the area between two immediately adjacent overload constrictions can be at least substantially the same. This enables the short-circuit current to be safely switched off via the fusible link.

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

Preferably, the distance between a cross-sectional constriction of the short-circuit constriction and / or the overload constriction to the immediately adjacent cross-sectional constriction of the short-circuit constriction and / or the overload constriction is at least essentially the same. The cross-sectional constrictions of the overload constrictions and the short-circuit constrictions of the fusible conductor are particularly preferably at least substantially regularly spaced. This enables a simplified creation of the cross-sectional constrictions by equipping fusing of the fuse wire, with the behavior in the event of an overload and a short circuit being ensured by switching off the current, in particular the direct current, by melting the fuse element.

It is particularly preferred that the distance between immediately adjacent cross-sectional constrictions of the overload point and / or the short-circuit constriction is between 1 and 50 mm, preferably between 5 and 30 mm, more preferably between 10 and 20 mm and in particular at least substantially between 16 and 18 mm . The aforementioned distance can in particular be the distance between immediately adjacent short-circuit constrictions and / or the distance between an overload constriction and the immediately adjacent short-circuit constriction.

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 substantially between 60 to 70 mm.

Furthermore, the length of the cross-sectional constriction of the overload constriction can be made greater than the length of the cross-sectional constriction of the short-circuit constriction. 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 between 1: 0.3 to 1: 0.9, preferably between 1: 0.5 to 1: 0.85, more preferably between 1: 0.7 to 1: 0.8 and in particular at least substantially 1: 0.75. Over the longer length of the overload constriction, shutdown in the event of an overload can be ensured by changing the fuse wire when it heats up. In combination with the minimum width of the overload constriction and the shape of the overload constriction, the increased length enables the overload case to be protected by melting the fusible conductor even if there is no short circuit.

In particular, the extended web length enables the fusible conductor to respond more quickly in the event of an overload.

The first and / or the second layer is particularly preferably designed as a coating. A coating by means of the material of the first and / or the second layer enables a targeted and purpose-oriented application in the first and / or in the second section and thus in particular ensures a possible area-wise or circumferential application with the first and / or second layer that completely surrounds the fuse wire. The first and / or second layer can be applied in a targeted manner in their respective sections, in particular wherein inline production is made possible by a coating application.

In addition, the length of the cross-sectional constriction of the overload constriction can preferably be between 1 and 5 mm, preferably between 1.5 and 3 mm, in particular wherein the length of the overload constriction is at least essentially 2 mm.

In a further particularly preferred embodiment of the inventive concept, the fusible wire has an at least substantially rectangular cross-sectional shape. As an alternative or in addition, it can be provided that the fusible wire is designed as a flat band, in particular wherein the band width or the fleas of the flat band can be 0.04 ± 0.02 mm. The fusible wire designed as a flat band can - produced by punching, in particular by means of stamping - have the recesses of the overload constriction and / or the short-circuit constriction.

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

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

Alternatively or additionally, the fusible wire can have and / or consist of an electrically conductive material, in particular copper and / or a copper alloy, as material. At least essentially pure silver is particularly preferably used. The 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 substantially equal to 99.99%. A purity of silver of 99.99% indicates the proportion of silver (Ag) in the material. Accordingly, the silver is preferably designed as 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.degree. C., in particular between 950 to 970.degree. C., in particular wherein the melting temperature of the fusible wire can be 961.degree. 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 in low-voltage fuses as a material for the fuse wire, is advisable due to the permanently higher temperatures that arise when operating a HV HRC fuse. The use of copper could lead to oxidation of the surface of a high-voltage fuse and, in particular, have fatal consequences if the direct current is switched off.

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

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

In the case of a sequence-like arrangement of the overload constriction points, the first section is arranged in particular at least once, preferably once, between a pair of overload constriction points.

In the case of a sequence-like arrangement of the overload constrictions in the fusible conductor, it is preferably provided that the sequence of overload constrictions with short-circuit constrictions arranged in between is at least substantially regular and / or structurally identical.

The ratio of the maximum width of the fuse 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 to 1: 0.2, preferably 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 to 2 mm, more preferably at least substantially 1.6 mm.

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

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 from one another.

It goes without saying that the aforementioned preferred embodiments of the fusible conductor according to the invention and / or those in connection with the inventions fusible conductor according to the invention can 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 the relevant explanations.

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

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

To transmit the direct voltage, the length of the fusible conductor required for this is used, which does not correspond to the entire length of the fuse because the fusible conductor is ultimately wound around the bobbin. Ultimately, the length of the fuse element 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, in particular at least essentially at each turn, rests in certain points - possibly at several support points. Accordingly, the winding body can have projections and depressions resulting between the projections. An at least essentially star-shaped design of the wound body is very particularly preferred.

The direct 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 to 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 voltage range at which the fuse is used and / or is tested for the fuse. Basically a distinction must be made between an upper rated voltage and a lower rated voltage, whereby the lower rated voltage indicates the voltage at which the fuse still switches, while the upper rated voltage represents the upper limit for the direct 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 secured by the fuse.

In a further very 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 to 700 A, preferably between 5 A to 500 A, more preferably between 15 A to 300 A.

Alternatively or additionally, the invention can provide that the smallest breaking current of the fuse is greater than or equal to the rated amperage, in particular greater than or equal to twice the rated amperage, preferably greater than twice and / or less than 15 times the rated amperage, more preferably greater than that three times and / or less than eight times the rated current. The aforementioned relative dimensioning of the smallest breaking current is advantageous in that, in particular, the smallest or the minimum breaking current is directly dependent on the rated amperage 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 to 100 kA, preferably between 10 kA to 80 kA, more preferably between 10 kA to 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 direct current that the fuse can switch at most. Consequently, the rated switching capacity of the fuse should be greater than the maximum short-circuit current at the point where the fuse is used. In addition, according to a further embodiment of the inventive concept, 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 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 amperage 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 purpose. Thus, the type of fuse can be selected in particular as a function of 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 of the direct current secured by the fuse and the 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 output of the consumer secured by the fuse and / or the consumers (total output). Ultimately, the aforementioned product corresponds in particular to the performance that can be secured by the backup.

According to a further preferred embodiment it is provided that the fuse has at least two fusible conductors, preferably between 2 to 10 fusible conductors, more preferably between 3 to 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 which are arranged in the medium-voltage direct current area and / or in the high-voltage direct current area. The medium voltage direct current range is to be understood as meaning in particular 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. The high-voltage direct current range is to be understood as meaning, in particular, a voltage range of over 60 kV, preferably over 100 kV, more preferably over 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 English: 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 system.

Alternatively or additionally, the invention can provide that the direct current comes from a photovoltaic system and / or a photovoltaic area system, in particular a solar park, and / or a wind turbine and / or a wind park, in particular an offshore wind park. Alternatively and / or in addition, it is possible according to the invention that the electricity coming 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 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 being fed into the network.

The fuse housing of the fuse is preferably designed as a hollow cylinder and / or tube. The top and bottom of the fuse housing are in particular designed to be open at least in some areas.

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

In particular, the contact cap can have a diameter between 30 to 100 mm, preferably between 50 to 90 mm. It is preferably provided that the contact cap has 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 through the overlapping in the front area of the fuse housing.

According to a further preferred embodiment, a further top 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. The two-part design of the contact cap enables reliable electrical contact to be achieved, which is particularly advantageous in long-term use. Furthermore, this embodiment enables a particularly firm connection or arrangement of the contact cap on 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 a multitude of inorganic, non-metallic materials which can preferably be subdivided into the types of earthenware, stoneware, stoneware, porcelain and / or special sizes. Electro-ceramics 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 a material made of plastic, preferably melamine, and / or made of a glass fiber reinforced plastic and / or consists of it. 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 serves to extinguish an arc and / or to cool down the possibly melted fusible conductor or the remnants 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 substantially hermetically encapsulated. A hermetic encapsulation or sealing is to be understood as meaning an airtight and / or gas-tight seal of the system, in particular protected from water and / or liquids.

According to a further embodiment of the invention it is provided that the fusible conductors are connected electrically in parallel and / or are at least substantially wound around the winding body in an essentially helical manner. 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 fusible conductor 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 wound body has and / or consists of flat porcelain as the material. In addition, the winding body can be designed such that a plurality of chambers are formed, in particular wherein a cross-sectional constriction can be provided in one chamber. Due to the cross-sectional constriction, a large number of partial arcs can arise when the fuse is triggered on each fusible link, so that the amount of heat converted can be evenly distributed over the entire length of the fuse tube when the fuse is switched off.

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

The striker of the striker trigger mechanism of the triggering device can be triggered by an auxiliary fusible conductor. In particular, the striker is triggered in the event of a short circuit.

A pretensioned spring is preferably assigned to the striker, wherein the spring can be designed such that when the auxiliary fusible conductor is triggered, in particular in the event of a short circuit, the striker emerges from the end face of one of the contact caps. In particular, the striker can act on a load switch, which can then switch off the faulty current on all poles.

It is particularly preferably provided that the auxiliary fusible conductor extends over the entire length of the fuse housing and / or axially through the center of the winding body. Accordingly, the auxiliary fusible conductor in particular does not have to be wound around the winding body.

In addition, the auxiliary fusible conductor can be connected in parallel with the fusible conductor and / or the fusible conductors, in particular so that when a fusible conductor melts, the auxiliary fusible conductor is traversed by a current which leads to the activation of the striker.

A safety device can preferably be assigned to the triggering device, which is designed in such a way that after the firing pin has been triggered, it can no longer be pressed and / or displaced into the safety housing. If the strike pin is triggered accordingly, the safety device prevents the strike pin from being able to assume its position again before it was released. Thus, the load switch to be arranged on the striker can be operated permanently by the striker in the event of a short circuit - in particular as long as the direct current is to remain cut or switched off. At least one display device can be assigned to the fuse. In particular, the display device is designed to visually display a state. The display device can also be arranged in the contact cap. The display device can also be used as an alternative to the striker trigger mechanism and indicate the triggering of the fuse by means of an optical and / or acoustic signal. Ultimately, the display device serves to inform the operating staff that the HV HRC fuse has been triggered.

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 by direct current and with at least one fuse which has the fusible conductor according to the invention and is designed according to at least one of the embodiments described above. The direct current is transmitted to the consumer, whereby the direct current can be secured by the fuse. A consumer is preferably provided as the buyer.

To avoid unnecessary repetition, reference is made to the previous statements 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 fusible conductor according to the invention can be transferred to the system according to the invention.

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

Furthermore, it goes without saying that the aforementioned intervals and range limits contain any intermediate intervals and individual values contained therein and are to be regarded as disclosed as being 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 emerge from the following description of exemplary embodiments with the aid of the drawing and the drawing itself. All of the features described and / or illustrated form the subject matter of the present invention individually or in any combination, regardless of their Summary in the claims and their reference back.

It shows:

1 shows a schematic view of a fusible conductor according to the invention,

2 shows a schematic perspective illustration of a fuse according to the invention,

3 shows a schematic cross-sectional illustration of a further embodiment of a fuse according to the invention,

4 shows a schematic perspective illustration of a fusible conductor according to the invention wound around a winding body,

5 shows a schematic cross-sectional illustration of a further embodiment of a fuse according to the invention,

6a shows a schematic perspective illustration of a further embodiment of a fusible conductor according to the invention,

6b shows a schematic cross-sectional illustration along section AA from FIG. 6a, FIG. 6c shows a schematic cross-sectional illustration along the section BB from FIG. 6a,

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

8 shows a schematic basic illustration of a further embodiment of a use of a fuse according to the invention for securing direct current transmission.

1 shows a fuse element 1. As can be seen from FIG. 3, the fuse element 1 is provided for use for a DC fuse 2, in particular a floch voltage floch power direct current fuse 2 (FIFI DC fuse). The fuse 2 can be provided for securing a direct current application, as shown schematically in FIGS. 7 and 8.

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

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

Furthermore, FIG. 1 shows that adjacent to each of the overload constrictions 4, in a respective second section 8, a second layer 9 is provided that surrounds the outer jacket surface 6 of the fusible wire 3 at least regionally, preferably completely.

The overload constrictions 4 are arranged one after the other in the longitudinal direction L of the fuse wire 3. In the exemplary embodiment shown in FIG. 1, it is provided that the first section 5 is provided between the two immediately successive overload constrictions 4. The first layer 7 does not have to be arranged centrally between the two overload constrictions 4, but can do so in further embodiments.

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

According to the shape and the minimum width 1 1, 12 of the cross-sectional constriction, the response behavior of the fusible conductor 1 in the event of triggering - for overload protection - can be adjusted accordingly.

In the embodiment shown in FIG. 1, it is provided 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 1 1 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 to 1.5: 1. In further embodiments, the aforementioned ratio can 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 substantially 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 directly adjoins the overload constriction 4. In addition, Fig. 1 shows that the second layer 9 is solid, preferably material coherently and / or glued, is connected to the outer jacket 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) siloxate as 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.

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

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

In addition, FIG. 1 shows that a plurality of short-circuit constrictions 10 between two immediately successive overload constrictions 4 - viewed in the longitudinal direction L - are 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 successive overload bottlenecks 4.

Furthermore, FIG. 1 shows that the first layer 7 or the first section 5, which has the first layer 7, is arranged between two immediately successive short-circuit constrictions 10 on the outer jacket surface 6 of the fuse wire 3. The first section 5 can - but does not have to - be provided at least essentially centrally between two short-circuit constrictions 10.

In addition, FIG. 1 shows that the second sections 8 having the second layer 9 are arranged on the outer jacket surface 6 of the fusible wire 3 in such a way that between two immediately consecutive second sections 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 “frame” or “frame” the two immediately successive overload constrictions 4 and the short-circuit constrictions 10 arranged between them.

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

Furthermore, FIG. 1 shows that the corner or the corner region of the recess 13 has a rounding. A cross-sectional constriction of the overload constriction point 4, which has an at least substantially rectangular cross-sectional shape, can be formed by the recesses 13 having at least substantially the rectangular edge.

The detailed representation of the short-circuit constriction 10 in FIG. 1 clearly shows that the short-circuit constriction 10 is formed by a cutout 14 having an edge that is at least essentially in the form of a circular arc segment. The recesses 14 can be produced by punching. In particular, the cross-sectional constriction of the short-circuit constriction 10 and / or of the overload constriction 4 is at least substantially mirror-symmetrical, in particular with respect to the central axis of the fuse wire 3.

FIG. 6 a shows that the cross-sectional constriction of the short-circuit constriction 10 has an at least substantially circular arc-shaped contour — in the plan 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.

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

In FIG. 1 it is further shown that the distance 16 between a short-circuit constriction 10 and the directly adjacent overload constriction 4 is at least essentially 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, designed to be the same. In further embodiments, the distance 16 can correspond to the distance 15.

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 constriction 10, namely in embodiments in which no short-circuit constriction is provided and / or independent of the majority of the short-circuit constriction 10, namely in embodiments in which only a single short-circuit constriction 10 is provided between two immediately adjacent overload constrictions 4 , be formed at least substantially the same. The distance 17 ultimately indicates the distance between two immediately adjacent cross-sectional constrictions - viewed in the longitudinal direction L of the fuse wire 3 -, the cross-sectional constriction being 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 in particular 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 exemplary embodiment shown in FIG. 1, it is provided that the length 18 of the cross-sectional constriction of the overload constriction 4 is larger than the length 19 of the cross-sectional constriction of the short-circuit constriction 10. Ultimately, the cross-sectional constriction of the overload constriction 4 can be designed to be at least essentially elongated. The length 18 of the cross-sectional constriction of the load constriction 4 can be between 1 and 3 mm and in particular 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 designed as a coating.

In FIG. 1 it is shown that the first layer 7 in the first section 5 is applied on the top of the fuse wire at least essentially with a circular shape - seen in cross section.

The second layer 9 can be applied at least essentially ring-shaped, encasing or surrounding the fuse wire 3 on the outer jacket surface 6 of the fuse wire 3.

6b and 6c show the cross-sections of a further embodiment of the fusible conductor 1, wherein both the first layer 7 and the second layer 9 in their respective sections 5 and 8 at least essentially completely sheathing or surrounding the outer jacket surface 6 of the fusible wire 3 have been applied.

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

In Fig. 6a it 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 fusible wire 3, the first and / or the second layer 7, 9 have an at least substantially circular external cross section. It is not shown that the fuse wire 3 has metal as the material. At least essentially pure silver can be provided as the metal. In particular, the silver has a degree of purity of 99.99%. The aforementioned degree of purity indicates the proportion of Ag (silver) in the metal material. This is also known as fine silver.

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

It can be seen schematically from FIGS. 3 and 4 that the fusible conductor 1 has an alternating sequence of overload constrictions 4 in direct succession. In particular, a sequence-like sequence of the overload bottlenecks 4 and in particular the short-circuit bottlenecks 10 arranged between the overload bottlenecks 4 is provided. In the alternation of the overload bottlenecks 4, in particular an at least substantially structurally identical design of two directly successive overload bottlenecks 4 and in particular the short-circuit bottlenecks 10 provided between the overload bottlenecks 4 are provided. In the exemplary embodiment shown in FIG. 3, the overload constrictions 4 are at least substantially regularly spaced and are at least substantially the same distance from one another. The "pattern" shown in FIG. 1 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 repeating along the longitudinal direction L of the fuse wire 3.

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

In the embodiment shown in Fig. 1 it is provided that the ratio of the maximum width 20 of the fuse wire 3 to the minimum width 1 1, 12 of the cross-sectional constriction of the overload constriction 4 and / or the cross-sectional constrictions of the short-circuit constriction 10 between 1: 0.4 to 1: 0, 35 lies. In further embodiments, the aforementioned ratio can be between 1: 0.6 to 1: 0.2 and have any value within the specified interval. In Fig. 2, a fuse 2 for securing a direct current application is shown. In particular, a HH-DC fuse 2 is provided. The fuse 2 has an outer fuse housing 21, with at least one fusible conductor 1 wound around a, in particular electrically insulating, winding body 22 according to at least one of the embodiments described above being arranged in the fuse housing 21.

It is not shown 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, the formation of the cross-sectional constrictions of the short-circuit constrictions 10 and the overload constrictions 4 in combination with the first and second layers 7, 9 making it possible to use the fuse 2 as an HVDC fuse 2.

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

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

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

3 and 5 show that the winding body 22 is at least essentially star-shaped. The star-shaped design of the winding body 22 can also be seen clearly from FIG. The winding body 22 has — seen in cross section — projections 25 or webs, 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 for at least essentially punctiform support of the fusible conductor 1. The fusible conductor 1 does not lie on the surface of the winding body 22 between the projections 25. In the exemplary embodiment shown in FIGS. 7 and 8, the direct voltage of the direct current is greater than 1 kV and less than 100 kV. In further embodiments, the direct voltage can be between 1.5 kV and 50 kV or between 3 kV and 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, in the case of the fuse 2 used in a direct current network in FIGS. 7 and 8, it is provided 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 to 10 times the rated current, in particular the minimum or smallest breaking current being directly dependent on the rated current of the respective fuse link.

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

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

Depending on the transmitted direct current and the direct voltage, the product of the direct current secured by the fuse 2 and the direct voltage can vary. In the exemplary embodiment shown in FIGS. 7 and 8, the aforementioned product is 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. It is not shown that a plurality of fusible conductors 1 are arranged in the fuse housing 3. In further embodiments it can be provided that between 2 to 10 fusible conductors 1 are used.

It is not shown 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 greater than 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 a photovoltaic area system (i.e. a solar park) and / or a wind turbine 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 electricity generated by the aforementioned energy conversion systems can be securely transmitted to the consumer 29 by at least one fuse 2.

7 and 8 show a system 28 with a consumer 29 that can be supplied by direct current. In particular, the consumer 29 is a consumer or a plurality of consumers. Furthermore, the system 28 has a fuse 2, which is designed to protect the direct current transmitted to the consumer 29. It is not shown that the power of the consumer 29 is greater than 5 KW and less than 2000 MW. In particular, the fuse 2 is used in a direct current network.

Fig. 2 shows that the fuse housing 21 is hollow cylinder-shaped or tubular. On the front side, the fuse housing 21 is firmly closed by the contact caps 24, it being possible for the contact cap 24 to be placed on the fuse housing 21.

In FIG. 2 it is shown that the contact cap 24 covers at least a partial area of the jacket surface in the end area of the fuse housing 21. It is not shown that the contact cap 24 is assigned a further top 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.

The fuse housing 21 shown in Fig. 2 comprises a ceramic material. In further embodiments, the fuse housing 21 can consist of a ceramic material. Alternatively or additionally, the fuse housing 21 can have a plastic, in particular a gas-fiber reinforced plastic, as material.

It is not shown 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 extinguishing agent.

4 shows that the fusible conductor 1 is connected to the contact cap 24 in an electrically contacting manner.

It is not shown 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 through the formation of the second layer 9 or through the material of the second layer 9.

In addition, it is not shown that the fuse housing 21 is at least substantially 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 such that a plurality of chambers is formed, in particular with a cross-sectional constriction being provided in one chamber.

Furthermore, it is not shown 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 material. List of reference symbols:

1 fusible link

2 backup

3 fuse wire

4 overload point

5 first section

6 outer jacket surface of 3

7 first layer

8 second section

9 second layer

10 short circuit bottleneck

1 1 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 the short-circuit constriction and the overload constriction

17 Distance between cross-sectional constrictions

18 length of 4

19 length of 10

20 maximum width of 3

21 outer fuse box

22 bobbins

23 face

24 contact cap

25 ahead of 22

26 deepening of 22

27 DC power source

28 system

29 customers

L lengthwise

Claims

Patent claims:

1. Use of a fuse element (1) for a DC fuse (2) and a high-voltage high-performance fuse (2) (HH-DC fuse), the fuse element (1) having an electrically conductive fuse wire (3), wherein the fusible wire (3) has at least two overload constrictions (4) designed as a cross-sectional constriction, wherein, preferably between the two immediately successive overload constrictions (4), in at least one first section (5) one of the outer circumferential surfaces (6) of the fusible wire (3) At least regionally, preferably completely, surrounding, solder-bearing and / or first layer (7) consisting of it is provided, and adjoining each of the overload constrictions (4) in a respective second section (8) an outer jacket surface (6) of the fusible wire ( 3) circumferentially at least regionally, preferably completely, surrounding second layer (9) is provided.

2. Use according to claim 1, characterized in that the fusible wire (3) between two immediately consecutive overload constrictions (4) has at least one short-circuit constriction (10) designed as a cross-sectional constriction, in particular wherein the minimum width (11) and / or the shape of the cross-sectional constriction the overload constriction (4) differs from the minimum width (12) and / or the shape of the cross-sectional constriction of the short-circuit constriction (10).

3. Use according to claim 1 or 2, characterized in that the minimum width (1 1) 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), in particular where the ratio of the minimum width ( 1 1) 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) between 1.01: 1 to 3: 1, preferably between 1.1: 1 to 2: 1, more preferably between 1, 15: 1 to 1.5: 1.

4. Use according to one of the preceding claims, characterized in that the second layer (9) is at least substantially directly adjacent to the overload constriction (4) and / or that the second layer (9) is firmly, preferably cohesively, with the outer jacket surface ( 6) of the fuse wire (3) is connected.

5. Fusible conductor according to one of the preceding claims, characterized in that the second layer (9) has and / or consists of a plastic and / or poly (organo) siloxane as material, preferably as an arc extinguishing agent, in particular wherein the second layer (9 ) is designed to be electrically insulating.

6. Use according to one of the preceding claims, characterized in that the solder of the first layer (7) has a metal alloy as material and / or consists of it, in particular where the metal alloy is cadmium, lead, tin, zinc, silver and / or copper, preferably a metal alloy comprising tin and / or silver, in particular wherein the first layer (7) is designed to be electrically conductive.

7. Use according to one of the preceding claims, characterized in that between two immediately successive overload constrictions (4) a plurality of short-circuit constrictions (10) is provided, in particular wherein between two overload constrictions (4) between 2 to 15, preferably between 3 to 6, Short-circuit constrictions (10) are provided and / or wherein the first section (5) having the first layer (7) is arranged between two immediately successive short-circuit constrictions (10) on the outer jacket surface (6) of the fusible wire (3).

8. Use according to one of the preceding claims, characterized in that the second sections (8) having the second layer (9) are arranged on the outer jacket surface (6) of the fusible wire (3) in such a way that between two immediately consecutive second sections ( 8) and / or second layers (9) the two overload constrictions (4) and preferably the short-circuit constriction (10) arranged between the overload constriction (4) and / or the short-circuit constriction (10) are provided.

9. Use according to one of the preceding claims, characterized in that the overload constriction (4) is formed by recesses (13) having an at least substantially rectangular edge.

10. Use according to one of the preceding claims, characterized in that the short-circuit constriction (10) by an at least essentially Chen circular arc segment-shaped edge having recesses (14) is formed.

1 1. Use according to one of the preceding claims, characterized in that the short-circuit constrictions (10) arranged between the overload constrictions (4) are at least substantially regularly spaced and / or that the distance (15) between two immediately adjacent short-circuit constrictions (10) and / or the distance (16) between a short-circuit constriction (10) and the immediately adjacent overload constriction (4) is at least essentially the same and / or that the distance (17) between a cross-sectional constriction of the short-circuit constriction (10) and / or the overload constriction (4 ) is formed at least substantially the same as the immediately adjacent cross-sectional constriction of the short-circuit constriction (10) and / or the overload constriction (4).

12. Use according to one of the preceding claims, characterized in 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).

13. Use according to one of the preceding claims, characterized in that the first and / or the second layer (7, 9) is / are designed as a coating.

014. Use according to one of the preceding claims, characterized in that the fuse wire (3) has an at least essentially rectangular cross-sectional shape and / or is designed as a flat strip and / or that the fuse wire (3), the first and / or second layer ( 7, 9) have an at least substantially circular outer cross section.

15. Use according to one of the preceding claims, characterized in that the fusible wire (3) has metal as the material, in particular wherein the material has, in particular, at least essentially pure silver and / or a silver alloy and / or copper and / or a copper alloy.

16. Use according to one of the preceding claims, characterized in that the fusible conductor (1) has an alternating sequence of immediately one after the other of the following overload bottlenecks (4), preferably with short-circuit bottlenecks (10) arranged between two immediately successive overload bottlenecks (4), in particular wherein the overload bottlenecks (4) are at least substantially regularly spaced.

17. Use according to one of the preceding claims, characterized in that the ratio of the maximum width (20) of the fuse wire (3) to the minimum width (1 1, 12) of the cross-sectional constriction of the overload constriction (4) and / or the cross-sectional constriction of the short-circuit constriction (10) between 1: 0.6 to 1: 0.2, preferably between 1: 0.5 to 1: 0.3, more preferably between 1: 0.4 to 1: 0.35.

18. Fuse (2) for securing a direct current transmission, in particular HH-DC fuse, with an outer fuse housing (21), wherein in the fuse housing (21) at least one fusible conductor (1) wound around a, in particular electrically insulating, bobbin (22) ) is arranged with the structural features of at least one of the preceding claims.

19. Fuse according to claim 18, characterized in that the fuse housing (21) is at least partially open on two end faces (23), with at least one contact cap (24) designed for electrical contact being arranged at the end of the fuse housing (21).

20. Fuse according to claim 18 or 19, characterized in that the direct voltage of the direct 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 less than 150 kV, preferably less than 100 kV, more preferably less than 75 kV, and / or between 1 kV to 100 kV, preferably from 1.5 kV to 50 kV, more preferably from 3 kV to 30 kV.

21. Fuse according to one of the preceding claims, characterized in that the smallest breaking current of the fuse (2) is greater than 3 A, preferably greater than 5 A, more preferably greater than 10 A, and / or less than 1 kA, preferably less than 500 A, more preferably less than 300 A, and / or between 3 A to 700 A, preferably between 5 A to 500 A, more preferably between 15 A to 300 A, and / or that the smallest breaking current of the fuse ( 2) is greater than or equal to the rated current, in particular greater or equal to twice the rated amperage, preferably greater than twice and / or less than 15 times the rated amperage, more preferably greater than 3 times and / or less than 8 times the rated amperage.

22. Fuse according to one of the preceding claims, characterized in that the rated switching capacity (rated value of the largest breaking current) is greater than 1 kA, preferably greater than 10 kA, more preferably greater than 20 kA, and / or between 1 kA to 100 kA, preferably between 10 kA to 80 kA, more preferably between 20 kA to 50 kA.

23. Fuse according to one of the preceding claims, characterized in that the transmitted direct 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 between 3 A and 100 kA, preferably between 10 A to 75 kA, more preferably between 15 A to 50 kA.

24. Fuse according to one of the preceding claims, characterized in that the product of the direct current secured by the fuse (2) and the direct voltage is greater than 5 kW, preferably greater than 50 kW, more preferably greater than 700 kW, and / or 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.

25. System (28) with a consumer (29) that can be supplied by direct current, in particular a consumer, with at least one fuse (2) according to at least one of the preceding claims, wherein the direct current transmitted to the consumer (29) can be safeguarded by the fuse (2) is, in particular where the power of the consumer (8) is greater than 5 kW, preferably greater than 50 kW, more preferably greater than 700 kW, and / or less than 3000 MW, preferably less than 2000 MW, more preferably less than 1000 MW, and / or between 50 kW and 3000 MW, preferably between 50 kW and 2000 MW, more preferably between 700 kW and 1000 MW.