WO2020057925A1

WO2020057925A1 - Disconnection apparatus for a surge arrester and surge arrester comprising the disconnection apparatus

Info

Publication number: WO2020057925A1
Application number: PCT/EP2019/072987
Authority: WO
Inventors: Oliver DUWE; Thomas Hilker
Original assignee: Siemens Aktiengesellschaft
Priority date: 2018-09-18
Filing date: 2019-08-28
Publication date: 2020-03-26
Also published as: DE102018215830A1

Abstract

The present invention relates to a disconnection apparatus (41, 70) for a surge arrester, having a first connection means (1) and a second connection means, and an electrically conductive connection (4, 6) between the two connection means (1), characterized in that a burst tank (5) which is filled with a fluid (42) is provided, wherein the fluid (42) is designed to at least partially destroy the burst tank (5) above a prespecified temperature limit, and in that an acceleration means (7) is provided, which acceleration means can be triggered by the at least partial destruction of the burst tank (5) in order to move the second connection means away from the first connection means (1) so as to form a disconnection section. The present invention further relates to a surge arrester comprising the disconnection apparatus.

Description

description

Disconnect device for a surge arrester and surge arrester with the disconnect device

The invention relates to a disconnection device according to the preamble of claim 1 and a surge arrester according to claim 15.

Surge arresters are used in the medium-voltage and high-voltage range in order to reliably reduce so-called overvoltages, i.e. voltages far above the nominal voltages provided during operation. This will damage equipment such as Avoided transformers. For example, a surge arrester for high voltage can be arranged on an overhead line and lead to impermissibly high currents to earth in the event of a lightning strike or short circuit.

Surge arresters usually contain so-called varistors, i.e. electrical resistors, the electrical resistance of which is very high up to a design-related threshold voltage and greatly reduced above the threshold voltage, so that the surge arrester becomes a good electrical conductor. E.g. Metal oxide resistors in disc form arranged one above the other in a housing and connected at the respective ends of the housing with the high voltage potential and the earth potential. The surge arrester is hardly conductive during normal operation, so that only a small leakage current flows to earth. In the event of a fault, however, a high leakage current flows.

However, in the long-term operation of a surge arrester, damage to or in the arrester can occur, which can result in such a high short-circuit current flowing through the arrester that gas development occurs inside the arrester. In this case, a surge arrester can explode in an uncontrolled manner and endanger people and other equipment. To prevent this, so-called Abtrennvor devices are often used. These disconnect devices trigger a blank cartridge when there is a current flow that exceeds a certain duration and strength (the limits are determined by the design of the separator device). The blank cartridge is in a fluid-tight chamber for this purpose, which is filled with escaping gas when the cartridge is released and thus pressurized. Then the pressure in the chamber tears the housing wall like a pipe bomb.

The explosion of the blank cartridge destroys the housing of the separating device and blows up e.g. a connected earth cable. In this way, there is no explosion of the conductor itself, but a smaller, controlled explosion on the disconnector.

Known, for example, from document DE 100 25 685 A1 is a separating device in which a spiral spring is inserted in order to press a resistance element onto an explosive device or blank cartridge. A current path is formed which, in the event of a fault, generates strong heat together with an arc ignited in a cavity arranged beneath it. The heat triggers the blank cartridge, destroys the housing of the disconnecting device and blows off a connecting bolt to ensure a safe disconnection. It is known in the art that blank cartridges typically fire at a temperature of approximately 185 ° C.

It is problematic, however, that the explosion of the blank cartridge can release heated particles, such as housing fragments or parts of the cartridge, which fall down to earth. In particularly dry, bush fire-prone regions of the world, such as in California or Australia, these particles can trigger forest or bush fires that endanger human life and cause great damage to property. In such regions, grassy areas below the arrester are therefore constantly replaced by the in the dry months of the year the respective overhead line operator mowed and the combustible material removed. This reduces the risk of fire if a disconnect device trips. This mowing to thousands of places on a power grid is personnel and cost intensive.

The object of the invention is to provide a separating device which is comparatively simple and inexpensive to produce and which allows a comparatively particularly safe use in fire-prone regions.

The invention solves this problem by a Abtrennvorrich device according to claim 1.

The first connection means is for example for one

electrically conductive connection formed with a surge arrester. The second connection means is, for example, designed for an electrically conductive connection with an underground cable.

Surprisingly, it has been shown that a bursting container filled with a heat sensitive fluid in a mechanically biased separation device is sufficient to provide for an interruption of the current path in the event of a fault. The principle of a fluid-filled bursting container is used, for example, in sprinkler systems. A fluid-tight glass cylinder with a shape that essentially resembles medical ampoules is used as the bursting container. A special liquid and a small amount of gas are enclosed in the glass cylinder. When the temperature rises, the liquid in the glass cylinder expands. The pressure increases until the glass cylinder bursts and releases a sprinkler cap. Fire water is distributed evenly over a fire in the form of a spray rain. Suitable special liquids, depending on the glass vessel used and the application, have release temperatures that lie between 57 ° C and 182 ° C, for example. Commercial liquids are described on Wikipedia, which are used for easy detection of the trigger temperature are color-coded (permanent link:

https: // de. wikipedia. org / w / index. php? title = sprinkler system & ol did = 176835902). Bright red liquid triggers at 57 ° C, red at 68 ° C and violet only at 182 ° C. The yellow (79 ° C), green (93 ° C) and blue are in the intermediate range

(141 ° C) liquids. Blue-black liquid at 340 ° C is also known. The trigger temperature of the sprinkler is selected so that it is approx. 30 ° C above the maximum expected room temperature. This ensures, on the one hand, that the sprinkler triggers before major damage has occurred, and, on the other hand, that the sprinkler system can be triggered without the risk of fire. Details on the liquids and the glass cylinders or ampoules used are contained in "DIN EN 12259-1: 2006 Fixed fire extinguishing systems - Components for sprinkler and water spray systems - Part 1: Sprinklers". Nominal trigger temperatures are listed on page 9 in table 2. Strength requirements for the bursting container made of glass are given on pages 39 below.

Using this principle of temperature-dependent destruction of a component, numerous designs can be implemented, from which a person skilled in the art will select a suitable variant, taking into account the design of the disconnecting device, the required trigger temperature and the tolerable time until triggering in the event of a fault. In principle, any combination of a fluid, that is to say possibly also a gas or gas mixture (possibly under high pressure) and a bursting container, can be used that meets the requirements. If the required trigger temperature is very low, for example when using a separating device in polar regions, a thin glass ampoule filled with water, for example, could suffice (if necessary with an antifreeze to prevent freezing). This would give a trigger temperature of 100 ° C in about wa. It is an essential advantage of the invention that the separating device can be used without the use of pyrotechnic products. This means that no hot particles or sparks can arise that could start a fire. The separation device according to the invention can also be used where pyrotechnic triggers are not permitted. Another advantage is that the components of the separating device can be reused even after they have been triggered if the liquid-filled or gas-filled container is replaced. This protects the environment and saves costs.

In a preferred embodiment, a liquid is used as the fluid, which is suitable to at least partially disrupt the bursting container above a temperature limit of 120 ° C. by a temperature-dependent increase in volume.

In a preferred embodiment, a liquid is used as the fluid which is suitable for at least partially disrupting the bursting container by a temperature-dependent volume increase above a temperature limit of 170 ° C. This is an advantage because it roughly corresponds to the trigger temperature of commercially available blank cartridges. At this temperature, on the one hand, false triggers caused by heat from equipment and or direct sunlight in summer are prevented because the trigger temperature is not reached. On the other hand, the trip temperature is low enough to quickly and safely trip the disconnect device when a fault occurs. A liquid is preferably used as the fluid, which has a trigger temperature between 170 ° C and 250 ° C. For example, the liquid marked with the color violet can be used according to the Wikipedia article mentioned above, which has a trigger temperature of 182 ° C. This is a particular advantage because ready-to-use glass cylinders are standardized with the liquid and are available at very low cost. This makes the Abtrennvor direction inexpensive to manufacture. Furthermore, in State of the art documented numerous positive experiences with blank cartridges that trigger at a comparable temperature.

In a preferred embodiment of the separating device according to the invention, the accelerating means has a first spring biased in normal operation of the separating device. Normal operation in the sense of the invention is a state in which the surge arrester functions properly and a leakage current can flow away to earth in a controlled manner via the disconnection device. This is an advantage because springs are simple and inexpensive to manufacture and long durability can be achieved even under pretension.

In a preferred development of the aforementioned embodiment, the first spring is formed as a first spiral spring. This is an advantage because a spiral spring has essentially a cylindrical jacket-like shape, which can be particularly easily trained with cylindrical contacts can insert disconnector.

In a further preferred embodiment of the separating device according to the invention, the accelerating means is based on a movable contact which is connected to the second connecting means. This is an advantage because, in the event of a fault, the accelerating means can throw the movable contact and the second connecting means attached to it out of the separating device.

In a further preferred embodiment of the separating device according to the invention, the electrically conductive connection has a first current path with an electrical resistor and a second current path with an arcing chamber, the bursting container being arranged on the arcing chamber in such a way that in the event of a fault by an arc in the arc chamber and / or heat on the first current path the fluid is heated sufficiently to to destroy the burst container at least partially. This is advantageous because it is possible to precisely coordinate the duration and amperage of a leakage current in order to ensure that the disconnection device is triggered only in the event of a fault.

In a further preferred embodiment of the separating device according to the invention, a locking device is designed to determine the accelerating means in normal operation of the separating device in such a way that the second connecting means is electrically conductively connected to the first connecting means, and to release the accelerating means in the event of a fault the formation of the separation distance to he possible.

In a further preferred embodiment of the separating device according to the invention, the locking device has at least one locking means which, during normal operation of the separating device, is arranged in a recess of the movable contact and in a recess of a fixed contact, with a locking body slipping out of the lock by means of the recess of the prevents moving contact. A single locking device such as e.g. a ball made of metal or a hard plastic, but if necessary, two or more locking means can be used with advantage, for example in order to achieve a reduced bending load with a circumferential distribution around the movable contact with the same Winkelab. This largely prevents accidental jamming of the locking device.

In an alternative preferred embodiment of the separating device according to the invention, the locking device has at least one locking means which is arranged in normal operation of the separating device in a recess of the fixed contact and in a recess of the movable contact, with a locking body slipping out of the locking means from the recess of the fixed contact prevented. This embodiment uses the same functional principle as the aforementioned embodiment, but the movable contact here is arranged overlap pend outside via the fixed contact. This means, for example, that the acceleration medium is outside the fixed contact.

In a further preferred embodiment of the separating device according to the invention, an unlocking means is formed to move the locking body in the event of a fault, so that the at least one locking means is released so that the at least one locking means slips out of the respective recess and the accelerating means the movable contact from the first connection means moved away. This is an advantage because a particularly safe design is achieved, so that false trips are prevented.

In a further preferred embodiment of the separating device according to the invention, the unlocking means has a second spring. This is an advantage because springs are simple and inexpensive to manufacture and long durability can be achieved even under pretension.

In a further preferred embodiment of the separating device according to the invention, the second spring is designed as a second spiral spring. This is an advantage because a spiral spring has essentially a cylindrical jacket-like shape, which can be particularly easily can insert disconnect device designed with cylindrical contacts.

In a further preferred embodiment of the separating device according to the invention, a locking device is provided in order to releasably fix the movable contact on the fixed contact for transport and storage. This is particularly advantageous because numerous countries stipulate in corresponding transport regulations that accidental triggers must not pose a risk to people or material. If this is not sufficient, expensive transport safeguards such as transport boxes are required.

In a further preferred embodiment of the separating device according to the invention, the locking device has a thread on a contact area between the movable contact and the fixed contact, so that a screw connection can be formed by rotating the movable contact against the fixed contact. The integrated thread ensures that false accidents are easily prevented. No other components are required for securing.

It is also an object of the invention to provide an overvoltage arrester which is provided with a separating device which can be produced in a comparatively simple and cost-effective manner and which permits comparatively particularly safe use in regions at risk of fire. The inven tion solves this problem by a surge arrester according to claim 15. There are, accordingly, the same parts before as explained for the Abtrennvorrich device according to the invention.

For a better explanation of the Abtrennvor direction according to the invention preferred exemplary embodiments are indicated in the figures. Show

Figure 1 shows a first embodiment of an inventive separation device, and

Figure 2 is a detailed view of the first embodiment according to claim 1, and

Figure 3 is a detailed view of a movable contact, and

Figure 4 shows a second embodiment of an inventive separation device. FIG. 1 shows a cross section through a separating device 41 according to the invention. FIG. 2 shows an enlarged section of FIG. 1. The separating device 41 is triggered thermally, but is not based on the principle of the pyrotechnic propellant charge. No blank cartridge or the like is used as an explosive device.

The separating device 41 has an electrically insulating housing 2, which is essentially pot-shaped or bell-shaped. The housing 2 is arranged with its closed side (the “pot bottom”) on a first connection means 1, which serves as an electrode for a connection to a surge arrester (not shown). For this purpose, the first connection means 1 has a bore 20 with an internal thread This exemplary embodiment is essentially rotationally symmetrical, so that many parts are cylindrical (ie circular in the longitudinal section), for example to be able to be plugged into one another. However, it is clear to the person skilled in the art that practically any other geometry in the longitudinal section is like For example, a hexagon or a square can be constructed with the same functional principle if the individual components match each other or can be plugged into one another, for example.

A second connection means is arranged at the other end of the separating device 41. The second connection means is designed, for example, as a short screw (not shown) to which an underground cable can be connected. To assemble the disconnecting device, an assembly aid is shown, which has a connection bolt 50 with a screw head 11. At the connection bolt 50 is fixed in a locking body 8 by screwing into a thread. With the assembly aid, the disconnecting device can be installed in the pretensioned state. For operation on a surge arrester, the assembly aid is removed from the locking body 8. The short screw is screwed as a second connection means into a thread 62 in a movable contact 10 and the earth cable is connected (not shown). Between the two connection means 1, there is normal operation of the arrester and the separating device 41, that is to say before the disconnecting device 41 is triggered, an electrically conductive connection. The first connection means 1 adjoins an arc chamber 60, which provides an alternative current path for a leakage current. The arc chamber 60 has a conductor arc 61 which bulges semicircularly in the direction of a counter contact 13. The Lichtbogenkam mer 60 is laterally delimited by a wall 21 which is surrounded on the outside with an insulator material 4. The arc chamber 60 is arranged on a fixed contact 6, which is designed as a hollow cylinder. An electrical resistor 3 bridges the arc chamber 60 by providing an electrically conductive connection between the first connection means 1 and the fixed contact 6. The electrical resistor 3 and the arcing chamber 60 are matched to one another in such a way that, in normal operation, a leakage current can flow out of the arrester via the first connection means 1, the electrical resistor 3 and the fixed contact 6 into the movable contact 10. From there, the leakage current can flow to earth, for example, via an earth cable connected to the second connection means. However, if a leakage current exceeds the duration and strength of design-related limits, the Abtrennvor device 41 must trigger because, for example, a varistor column in the conductor is damaged and could cause a permanent short-circuit of an overhead line to earth. In such a fault, the voltage dropping across the arc chamber 60 is so high that an arc can form between the conductor arc 61 and the mating contact 13.

A rupture container 5, which is designed as a glass cylinder or as a glass ampoule, is arranged on the mating contact 13. A fluid is provided in the bursting container. In this case, a temperature-sensitive liquid 42 is contained in the burst container, which can expand above a predetermined temperature limit to such an extent that the burst container is at least partially destroyed. In the burst container 5 there is possibly a small air inlet 43 in addition to the liquid 42. The liquid 42 is, for example, a commercially available temperature-sensitive liquid for triggering sprinkler systems, which is suitable for at least partially destroying the bursting container 5 above a temperature limit of 120 ° C. For example, a normal liquid with a temperature limit of 182 ° C, coded with a violet color, can be used. If an arc occurs in the arc chamber 60 in the event of a fault, the heat development of the arc leads to the bursting container 5 bursting after a very short time.

An accelerating means has a biased in the normal operation of the disconnecting device 41 from the first coil spring 7 as Be accelerating means, which rests on the inside of the cylindrical fixed contact 6. The first coil spring 7 is supported at its end facing the first connection means 1 on a first shoulder 55. At its other end, the first coil spring 7 is supported on the movable contact 10, which is also in contact with the inside of the cylindrical fixed contact 6. In the example shown, the first spiral spring 7 is dimensioned such that its wire has a larger diameter than the wall thickness 51 of the pot wall 52 of the movable contact 10. In order to ensure displaceability, the movable contact 10 is tapered, i.e. that its diameter is, for example, smaller than the diameter 33, e.g. also has the diameter 32. This results in a circumferential step 56, so that the first coil spring 7 finds space between the movable contact 6 and the fixed contact 6.

A locking device 15 is optionally provided as an additional security measure for transport and storage. In a simple form, a thread is formed between the movable contact 10 and the fixed contact 6. Alternatively, a bayonet lock can be used. The movable contact 10 can be releasably fixed in the fixed contact 6 by one to several rotations. For use before Location can be solved by turning the screw connection of the locking device 15 - in the event of a fault, the disconnecting device 41 can then trigger and shoot the movable contact 10 out of the fixed contact 7.

The movable contact 10 is essentially designed as a cylinder which has a cylindrical recess 30 with an inner diameter 33. The movable contact 10 is thus also essentially pot-shaped with a “pot wall” 52 and a “pot base” 53, the open side of the pot facing the first connection means 1. A connecting bolt 50 projects into the area of the pot or into the recess 30. To the connection pin 50, a biased second coil spring 14 is placed. A locking body 8 has a recess for receiving the connecting bolt 50 and is screwed into it for assembly as explained at the beginning. By the pre-tensioned second coil spring 14, the locking body 8 is spaced at a distance 31 from the bottom of the cup-shaped second connection means. As a result, an air-filled cavity 30 is present. On part of its length, the locking body 8, in particular at its end facing the second connection means, has a taper with a second diameter 32 which is smaller than the inner diameter 33. This taper creates a ring-shaped step 24 formed recess that lengthens the air-filled cavity 30 in the direction of the first connection means 1.

FIG. 3 shows a detailed view of a movable contact 10. The contact 10 has two recesses 20, only one recess 20 being visible on the basis of the three-dimensional representation in FIG. The recesses 20 are, for example, circular bores which completely penetrate the “cup wall” 52 of the movable contact 10.

In the two recesses 20 of the movable contact 10, blocking bodies 9 are arranged, for example as balls or can be designed as a cylinder (in the case of cylindrical bores for the recesses 20). The locking body 9 are preferably only slightly deformable, ie provided with a hard surface. For example, the locking body can consist of metal or hard plastic. The diameter 38 of the blocking bodies, which are designed as balls in the exemplary embodiment, is preferably dimensioned such that there is only little play in the respective recess 20. The diameter 38 of the locking body 9 is greater than the wall thickness 51 of the “pot wall” 52 of the pot-shaped movable contact 10. On the inside, the locking body 8 lies against the pot wall 52 with little play, so that the respective locking body 8 is in normal operation of the separating device 41 cannot slide in. Since the locking bodies 9 each have a larger diameter 38 than the pot wall 52, they each protrude outwards from the recesses 20. The projecting part of the locking bodies 9 is in a recess, which acts as a circumferential groove 12 is inserted on the inside of the fixed contact 7. The groove 12 extends over a certain width along the inside of the fixed contact 7 in the direction of the pot bottom 53 of the movable contact 10. A threaded screw connection is provided for the optional locking device 15 , so for a rotatability of the movable contact 10, the groove 12 as annular groove.

The triggering of the disconnection device in the event of a fault will now be briefly explained below.

In the event of a fault, the leakage current no longer flows only through the resistor 4, but an arc is formed in the arc chamber 60. The heat of the arc

and / or the thermal energy of the current flow in the conductors acts on the liquid-filled bursting container 5. This supports in normal operation as a blockage the locking body 8, which is supported on the bursting container. The locking body 8 is tensioned by the second spiral spring 14 ge conditions the liquid-filled bursting container 5. If If the liquid 42 expands as a result of the heating, the bursting container 42 is destroyed. For example, a

Glass ampoule 42 used, e.g. bursts to its full extent and can therefore no longer support the locking body 8.

The second spiral spring 14 now displaces the locking body 8 in the direction of the first connection means 1, so that a radial movement of the locking body 9 in recesses 24 of the locking body 8, which are designed as a circumferential annular step 24, is possible. As a result, the first spiral spring 7 is released to push the movable contact 10 with the locking body 8 in the direction away from the first connecting means out of the separating device 41. The movement of the locking body 9 is facilitated by chamfered corners 33, 35 in the groove 12 and the annular step 24.

The movable contact 10 is thus driven by the first Spiralfe of 7 pushed out of the fixed contact 6 and the electrical current path is opened.

FIG. 4 shows a second exemplary embodiment of a separating device 70 according to the invention. In this variant, unlike in the first exemplary embodiment, there is no geic movement of the two springs 7, 14 when the separating device 70 is triggered. Both springs 7, 14 relax in this Variant in the same direction, namely away from the first connection means 1.

The fixed contact 6 is designed as a hollow body, in the interior of which a second coil spring 14 is biased in normal operation from the disconnecting device supported on a locking body 8. The locking body 8 is slidably supported on a bursting container 5, which is arranged on a pot bottom of a cup-shaped movable contact 10. The locking body 8 contains in this Vari ante the arc chamber. The movable contact 10 overlaps in this exemplary embodiment - in contrast to the first embodiment according to FIGS. 1 to 3 - outside the fixed contact 6 with the latter. A first coil spring 7 for separating the contacts 6, 10 lies outside of the fixed contact 6 on the latter and is biased in normal operation. The first coil spring 7 is based on the movable union 10 and the first connection means 1 abge.

In turn, an optional locking device 15 is provided, which provides transport and storage security by means of a screw connection or thread, in that the movable contact 10 and the fixed contact 6 are releasably fixed.

The triggering of the disconnection device 70 in the event of a fault will now be briefly explained below. If the bursting container 5 is destroyed in the event of a fault, the second coil spring 14 presses the locking body 8 in the direction of the pot bottom of the movable contact 10. This releases the locking bodies 9, which are located in recesses in the fixed contact 6, and can slide into the interior of the fixed contact 6 . This unlocks the freedom of movement of the movable contact 10, which can now be accelerated away from the first connection means 1 by the first coil spring 7.

Claims

1. Disconnecting device (41,70) for a surge arrester, having

a first connection means (1) and a second connection means, and an electrically conductive connection (4, 6) between the two connection means (1, 11),

characterized in that

a bursting container (5) filled with a fluid (42) is provided, the fluid (42) being designed to at least partially destroy the bursting container (5) above a predetermined temperature limit, and that

an acceleration means (7) is provided which can be triggered by the at least partial destruction of the bursting container (5) in order to move the second connection means away from the first connection means (1), forming a separation path.

2. Separation device (41,70) according to claim 1, characterized in that the fluid is a liquid (42) which is suitable, above a temperature limit of 120 ° C, the bursting container (5) by a temperature-dependent volume increase at least partially to destroy.

3. Separating device (41,70) according to claim 1 or 2, characterized in that the accelerating means has a first spring (7) preloaded during normal operation of the separating device (41,70).

4. separating device (41,70) according to claim 3, characterized in that the first spring is designed as a first spiral spring (7).

5. Separating device (41,70) according to one of the preceding claims, characterized in that the acceleration means (7) on a movable contact (10), which is connected to the second connection means (11).

6. Separating device (41,70) according to one of the preceding claims, characterized in that the electrically conductive connection (4,6,10) has a first current path (4,6,10) with an electrical resistor (4) and a second Has current path (7,10,13,61) with an arc chamber (60), the bursting container (5) being arranged on the arc chamber (60) in such a way that in the event of a fault, an arc in the arc chamber (60) and / or a heat development on the first current path (4,6) the fluid is heated sufficiently to at least partially destroy the bursting container (5).

7. separating device (41,70) according to one of the preceding claims, characterized in that a locking device (8,9,12,14,24) is formed,

during normal operation of the separating device (41, 70), the accelerating means (7) must be set such that the second connecting means is electrically conductively connected to the first connecting means (1), and

in the event of a fault, release the accelerator (7) to enable the separation path to be formed.

8. Separating device (41) according to one of the preceding claims, characterized in that the locking device (8, 9, 12, 14, 24) has at least one locking means (9) which, in normal operation of the separating device (41), in one Recess (20) of the movable contact (10) and in a recess (12) of a fixed contact (6) is arranged, wherein a locking body (8) slipping out of the locking means (9) from the recess (20) of the movable contact (6 ) prevented.

9. Disconnection device (70) according to one of claims 1 to 7, characterized in that the locking device (8,9,14) has at least one locking means (9) which, in normal operation of the disconnection device (70) in a recess of the fixed contact ( 6) and in a recess of the movable contact (10), wherein a locking body (8) prevents the locking means (9) from slipping out of the recess in the fixed contact (10).

10. Separating device (41,70) according to claim 8 or 9, characterized in that an unlocking means (14) is designed to move the locking body (8) in the event of a fault, so that the at least one locking means (9) will be released, so that the at least one locking means (9) slips out of the respective recess and the acceleration means (7) moves the movable contact (10) away from the first connection means (1).

11. Separating device (41,70) according to claim 10, characterized in that the unlocking means (14) has a second spring.

12. separating device (41,70) according to claim 11, characterized in that the second spring is designed as a second Spiralfe (14).

13. Separating device (41,70) according to one of the preceding claims, characterized in that a Arretierungsvor direction (15) is provided to releasably fix the movable contact (10) on the fixed contact (6) for transport and storage.

14. Disconnecting device (41,70) according to claim 13, characterized in that the locking device (15) has a Ge thread at a contact area between the movable contact (10) and the fixed contact (6), so that a screw connection by turning of the movable contact (10) against the fixed contact (6) can be formed.

15. Surge arrester with a disconnecting device

(41,70) according to one of claims 1 to 14.