Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01T—SPARK GAPS; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARKING PLUGS; CORONA DEVICES; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES
  • H01T1/00—Details of spark gaps
  • H01T1/14—Means structurally associated with spark gap for protecting it against overload or for disconnecting it in case of failure
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H79/00—Protective switches in which excess current causes the closing of contacts, e.g. for short-circuiting the apparatus to be protected
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01T—SPARK GAPS; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARKING PLUGS; CORONA DEVICES; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES
  • H01T2/00—Spark gaps comprising auxiliary triggering means
  • H01T2/02—Spark gaps comprising auxiliary triggering means comprising a trigger electrode or an auxiliary spark gap

Definitions

• Short-circuiting device for use in low and medium voltage systems for property and personal protection
• the invention relates to a further developed short-circuiting device for use in low and medium voltage systems for property and personal protection, comprising a switching element which is actuated by the trigger signal of a fault detection device, two opposing contact electrodes with means for supplying power, which to a circuit with terminals of different Potential are contactable, continue the contact electrodes under mechanical bias standing in the case of short circuit spring assisted perform a relative movement to each other, a sacrificial element as a spacer between the contact electrodes and with an electrical connection between the sacrificial element and the switching element on the one hand and one of the contact electrodes on the other hand, a current flow induced thermal destruction of the Targeting element to bring about specifically, according to the preamble of claim 1.
• the invention relates to a method for initiating a short circuit in low and medium voltage installations with a short-circuiting device.
• DE 43 31 992 Al discloses a secured against arcs cell-like switchgear for the distribution of electrical energy.
• DE 43 45 170 Al an arc fault Protective device for switchgear described, where there the actual switching or protective device is actuated by a signal from an AND operation of at least one photosensitive sensor and a light-insensitive sensor.
• the actual short-circuiter comprises a coil, wherein the short-circuiter generates a metallic short circuit between the parts to be short-circuited as a result of the forces which are produced by the induction current in cup-shaped metal parts under a vacuum.
• the energy storage source and the coil should be dimensioned so that the mentioned metallic short circuit takes place in a time between 0, 1 ms and 2 ms.
• a directly driven by a gas generator short-circuiting element is provided with a short-circuiting piston.
• the local short-circuiting piston should perform regardless of manufacturing tolerances optimal shock movement and at the same time be transport-secured.
• DE 42 35 329 Al belongs to a short-circuit device to the prior art, which consists of at least one switching element which is actuated by a trigger signal of an error detection device.
• the short-circuiter provided there comprises at least two electrodes receiving the switching element between them and has current-carrying parts or regions.
• min. at least one movable or deformable current-carrying region pressed against the electrodes and thus generates a metallic short circuit.
• the response times are insufficient and it is the overall design arrangement from a manufacturing point of view very expensive.
• a short-circuiting device for use in low and medium voltage systems which also includes a switching element which is actuated by a trigger signal of an error detection device.
• the switching element is a triggerable overvoltage protection device, which can be brought to a response by a current or voltage pulse and destructible in the event of an error.
• At least one of the surge arrester receiving electrodes is under mechanical bias and is movable toward the opposite electrode, the overvoltage protector forming an electrode spacer which, in the event of destruction, allows the electrodes to contact the short circuit.
• the aforementioned switching element may be a series circuit of a triggerable overvoltage protection device and a device with adjustable or defined melting integral. In this series connection, only the device with the defined melt integral can be destroyed in the event of a fault.
• the aforementioned device is a glass tube fuse, a linear or non-linear resistor, a varistor, a low-melting metal or a metal alloy, a semiconductive or conductive ceramic, such a glass, or the like.
• a tension or compression spring is used according to DE 103 13 045 B3.
• an embodiment of the electrodes as a pot with a counter electrode is common, which has a plunging into the pot die.
• said short-circuiting device should have a cost-effective to manufacture sacrificial element, which leads to a minimized loading of the switching element and the has the highest possible electrical conductivity to minimize the commutation with simultaneous high mechanical strength to use a high spring force with the aim of reducing the movement time.
• the object of the invention is achieved with a short-circuiting device according to the combination of features according to claim 1 or 12, being additionally referred to an inventive method for initiating a short circuit in low-voltage systems using the short-circuiting device according to the invention.
• this includes a switching element which can be actuated by the trigger signal of an error detection device. Furthermore, two opposing contact electrodes are provided with means for supplying power, wherein the contact electrodes can be contacted to a circuit with terminals of different potential.
• the contact electrodes under mechanical bias standing, spring-assisted in case of short circuit, a relative movement from each other.
• the sacrificial element which is provided as a spacer between the contact electrodes, is in electrical connection with the switching element on the one hand, and one of the contact electrodes, on the other hand, in order to purposefully bring about a thermal flow-induced thermal destruction.
• the sacrificial element is designed as a thin-walled hollow cylinder made of a refractory metallic material.
• the hollow cylinder is a structure of a pressure-resistant material, wherein the aforementioned filling is designed as a low-melting metal, for example.
• an insulating layer with low mechanical or even low temperature resistance can be arranged between the hollow cylinder and the actual conductive substance.
• the substance located in the interior is released and can already realize an electrically conductive short circuit or support such a short circuit even before closing or complete contact without mechanical movement of the main contacts.
• the hollow cylinder can be inserted and guided in recesses of the contact electrodes, so that a low contact resistance is given.
• an insulating body and an auxiliary electrode is located in the stationary contact electrode, wherein the auxiliary electrode is in communication with the sacrificial element.
• the opposing sides of the contact electrodes and the opposing surfaces may have a complementary conical shape with resulting centering effect in the case of short circuit contact.
• the ratio between the diameter and the wall thickness of the hollow cylinder is greater than 10: 1 selected.
• defined structures or changes in wall thickness in the hollow cylinder can form current paths, with the result of uneven heating under current load and deformation with concomitant loss of mechanical strength. It remains in this case advantageously the conductive connection between the contact electrodes, but decreases the mechanical resistance of the hollow cylinder, so that under the action of the spring force of the short-circuiter can be quickly converted into a closed state.
• a cavity can be formed between the contact electrodes in order to receive parts of the destroyed sacrificial element, without the desired low-resistance contact connection being impaired in the event of a short circuit.
• a venting channel or a venting bore which is effective in the closed state can be effective in order to prevent forces arising due to an increase in pressure in the event of a short circuit, in particular during the creation of an arc, which counteract the closing movement of the contact electrodes.
• the device for generating the biasing force can be designed as a compression spring, disc spring or the like spring arrangement.
• the sacrificial element is a wire or rod made of a low-melting-integral conductive material, the sacrificial element being in tension under mechanical bias.
• the movable contact electrode can form a contact bridge between two electrical terminals.
• the movable contact electrode can be designed as a displacement punch, which cooperates with a solid pot contact electrode, wherein in the pot contact electrode is a conductive, low-melting substance is located, which forms a complementary electrical bridge between the opposing contact portions when immersing the punch.
• the low-melting substance is forced out of the pot region of the corresponding electrode and enters the remaining gap of the opposing contact electrodes.
• the short-circuit current is then interrupted by the switching element after a predetermined time and the system is again loaded with mains voltage.
• the short-circuiting device reports the error that has occurred and thus indicates a necessary check of the system.
• FIG. 1 shows a first embodiment of the short-circuiting device with pressure-loaded movable contact electrode and hollow cylindrical sacrificial element.
• FIG. 2 shows an embodiment analogous to FIG. 1, but with a hollow-cylindrical sacrificial element which is at least partially filled with a conductive substance:
• FIG 3 shows a first variant of the second embodiment of the invention with zugbelastastetem rod or wire as a spring element.
• FIG. 4 shows a second variant of the second embodiment of the invention with zugbelastastenem sacrificial element.
• FIG. 5 shows a third variant of the second embodiment of the invention with zugbelastastenem sacrificial element.
• FIG. 6 shows a fourth variant of the second embodiment of the invention with zugbelastastenem sacrificial element and a pot electrode having a conductive substance to be displaced
• FIG. 7 shows a block diagram for explaining the method for initiating a short circuit in low-voltage systems with staggered connection.
• the sacrificial element 5 has a special significance with respect to the effective operation of the short-circuiting device.
• the aim of optimizing the short-circuiting device is to achieve the fastest possible closing movement of the main contacts and a very low load on the switching element.
• the speed of the closing movement the main contacts in addition to the contact distance, the mass of the moving contact, the effective counter forces also determined substantially by the force-displacement curve of the spring 4 used. The higher the initial force in the tensioned state and the higher the residual force in the closed state of the short-circuiter, the shorter the closing time of the main contacts.
• the mass of the moving contact and the spring force in the stressed state permanently act on the sacrificial element and require a certain mechanical strength.
• the sacrificial element is to be overloaded as possible due to a low power supply and the desired movement of the corresponding main contact, i. cause the respective contact electrode.
• the switching element is loaded with the fault current.
• the lower this load the lower the cost of the switching element can be kept.
• the impedance of the switching element and possibly the existing impedance of the arc and the substantially ohmic resistance of the sacrificial element is eliminated from the fault circuit.
• the sacrificial elements according to the invention have the following properties. There is a low melting integral (I 2 t value) of the material to minimize stress on the switching element.
• the sacrificial elements have a high electrical conductivity to minimize the commutation time and have a high mechanical strength to use a high spring force in view of a desired reduction in the movement time of the contact electrodes. Furthermore, there is only a low arc voltage in the destruction of the sacrificial element for the realization of a short commutation time. Forces which counteract the mechanical movement, such. As a resulting increase in pressure are avoided or reduced.
• the destructive behavior of the in particular hollow cylindrical material is so specifies that there is no impairment of the mechanical movement of the contact electrodes.
• the sacrificial element 5 is designed as a thin-walled hollow cylinder.
• a material for the hollow cylinder are particularly suitable due to the high mechanical strength steels or iron alloys.
• the thin-walled hollow cylinder geometry is chosen so that the ratio of diameter to wall thickness is substantially greater than 10: 1. This geometry has a much higher mechanical strength compared to a solid cylinder of the same material at the same melt integral. This makes it possible to specify higher spring forces and ensures faster closing times of the contact electrodes.
• the hollow cylinder according to the invention has a further advantage explained below, in particular at diameters of several millimeters.
• the hollow cylinder heats and melts unevenly even at high current loads and short melting times.
• This effect can be deliberately promoted by the current transfer at the contact points or by a structuring of the cylinder.
• structural material influences or even the use of composite material are conceivable.
• the hollow cylinder also does not melt or evaporate uniformly, as a result of which individual metallic bridges remain, and thus the arc-free behavior of the short-circuiter is maintained far into the kA range.
• a larger cavity or in addition a vent may be provided which limits the pressure build-up and thus the resulting counter forces.
• the arrangement of the sacrificial element, the main contacts and the gas flow is chosen or designed so that in an arc ignition of the arc commutes immediately from the auxiliary path with the switching element 9 on the two contact electrodes 2 and 6.
• the switching element 9 can already be relieved of the current flow before closing the contact electrodes.
• FIGS. 1 and 2 there is accordingly an electrically conductive housing 1 with a movable contact electrode element 2, which is prestressed under the action of a spring 4.
• the movable contact electrode 2 is insulated from the electrically conductive housing 1 by means of an insulation 3.
• an insulation 7 to the electrically conductive housing 1 and the contact electrode 6 is present.
• Reference numeral 10 symbolizes a conductive substance that can be used as a complete or partial filling of the hollow cylinder sacrificial element 5.
• the conductive substance 10 may be e.g. be designed as a low-melting metal or conductive liquid.
• FIGS. 3 to 6 the basic construction of the short-circuiter, as shown in FIGS. 1 and 2, can be inverted by the operating principle.
• the sacrificial element 5 is not loaded on compressive strength by the spring preload, but there is a stress on train instead.
• This embodiment makes it possible to use inexpensive wires or rods as the sacrificial element 5.
• the sacrificial element of the second embodiment in addition to the high tensile strength necessary for this design on a low melting integral.
• the spring 4 has, according to FIG. 3, a guide 12, which is used with an element 13 for transmitting power to the movable contact electrode 14.
• the elements 12 and 13 form a labyrinth seal, with the result that with a pressure increase in the seal interior, a movement support of the piston-like movable contact electrode 14 is ensured.
• the pressure wave generated by the arc in the variants according to FIGS. 3 to 6 does not counteract the closing movement of the contact electrodes, but can be used to accelerate the movement, as described above with reference to FIGS piston-shaped design one of the contact electrodes set forth has been.
• the design of the parts 12 and 13 with a suitable choice of material to achieve a sliding contact-like arrangement, which leads the current to close the main contacts.
• a matching of the current distribution between the sacrificial element and the parts 12 and 13 is required.
• the parts 12 and 13 are electrically contacted only after a minimal movement or that the contact takes place by a voltage flashover in the form of breakdown or slip over a small distance due to the ignition of the arc at the sacrificial element 5.
• constructions can be used in which the current forces support the movement of the moving element.
• FIG. 4 shows a variant embodiment with a wire-shaped sacrificial element 5, specifically with the aim of reducing the moving mass, which is also conceivable in principle with the tubular sacrificial elements which are under spring pressure according to FIG. 1.
• the contact electrodes 6 and 14 shown in FIG. 4 are fixed and only a movable contact plate 15 is used, which forms a bridge with respect to the contact electrodes 6 and 14.
• the arrangement shown in principle in FIG. 4 can also be realized in a coaxial-symmetrical manner analogous to the representation according to FIG. 5.
• the advantage of this embodiment is the small moving mass of the contact plate 15 and the low requirements in terms of current carrying capacity and the dynamic load of the connection between the contact plate 15 and one of the fixed main electrodes 6 and 14, which in the case of the embodiment of FIG. 5 was realized centrally.
• the power supply to the contact plate or to the sacrificial element can also be effected via a sliding contact of one of the fixed electrodes.
• the part 15 via a sliding contact with the first fixed main electrode 6.
• the second fixed contact electrode 14 is isolated from the case 1 by a part 7.
• a low-melting solder 10 or similar material may still be located in the bottom of the second fixed main electrode 14. This solder substance 10 can be forced between the fixed contacts 6 and 14 when heated, which increases the size of the conductive contact surface significantly.
• the fixed main electrode 14 is formed as a pot electrode, wherein the movable contact plate 15 when immersed in the melting solder 10 displaces this as mentioned above.
• the described short-circuiting allow the use of a self-extinguishing switching element such as spark gaps or thyristors, the application of a useful especially in the low voltage operating method for initiating a metallic short circuit.
• the short circuit In the case of fast-acting short-circuiters, the short circuit is initiated within the first residual current half-wave, permanently until it is disconnected by the upstream protective devices. The entire system is thus disconnected from the grid. As a result, even with possibly self-extinguishing wipers as a result of the shutdown is a high loss of use. On the other hand, if the duration of the response of the short-circuiter is delayed, the damage to the equipment in the case of a real damage event, on the other hand, increases considerably. In addition, a drastically higher maintenance costs. A delay of the short-circuiter also makes any desired personal protection unthinkable.
• the inventive principle of the method for initiating a short circuit is based on a staggered connection of the short-circuiter with the following timing.
• the switching element of the short-circuiter is briefly actuated.
• the possible short-circuit current through the switching element is limited by the sacrificial element and the impedance of the terminal and of the switching element.
• the current commutes from the fault location to the short circuiter.
• the switching element interrupts the short-circuit current and the system and the fault location are again loaded with mains voltage. In the case of a wiper and a sufficient reconsolidation of the fault remains the supply of the system.
• the short-circuiter reports the error that has occurred and thus indicates a necessary system check.
• the switching element of the short-circuiter is controlled again and permanently.
• the sacrificial element of the short-circuiter is overloaded in this case and generates a permanent metallic short circuit, which forces a shutdown of the system.
• the sacrificial element is designed so that a metallic short circuit can already be achieved after the lowest current loads (low I 2 t values).
• the switching elements used in this case must thus have only a very low current carrying capacity or a low switching capacity.
• Fig. 7 shows a schematic representation with respect to the parallel connection of another path.
• the additional parallel path consists essentially of a controllable switching element 17 with medium to high current carrying capacity and breaking capacity.
• an impedance 16 may be provided.
• the impedance With the help of the impedance, it is possible to influence the magnitude of the short-circuit current or the value of the square-wave current pulse, for example with non-linear impedances. On the one hand, this can be useful in order to avoid a response of possible overcurrent or undervoltage protection devices of the network during the first time-limited switching of the switching element and, on the other hand, not to exceed the maximum load with regard to current carrying capacity and extinguishing capability for less powerful switching elements.
• the height of the impedance 16 should not exceed a few 100 m ⁇ , since otherwise a commutation of the fault current to the overall device (short circuit path 1 and 2) is severely hindered.
• the impedance should be less than a few m ⁇ .
• semiconductor switches e.g. Thyristors or IGBTs, but also triggerable vacuum switch and spark gaps suitable.

Landscapes

• Fuses (AREA)
• Protection Of Static Devices (AREA)
• Emergency Protection Circuit Devices (AREA)
• Driving Mechanisms And Operating Circuits Of Arc-Extinguishing High-Tension Switches (AREA)

Priority Applications (2)

Applications Claiming Priority (3)

Related Child Applications (1)

Publications (2)

Family

ID=37398294

Family Applications (2)

Family Applications Before (1)

Country Status (6)

Families Citing this family (30)

Family Cites Families (13)

• 2005
  • 2005-10-06 DE DE102005048003A patent/DE102005048003B4/de not_active Expired - Fee Related
• 2006
  • 2006-07-04 AT AT06777558T patent/ATE433602T1/de not_active IP Right Cessation
  • 2006-07-04 DE DE502006003948T patent/DE502006003948D1/de active Active
  • 2006-07-04 PL PL08018404T patent/PL2051275T3/pl unknown
  • 2006-07-04 DE DE202006020737U patent/DE202006020737U1/de not_active Expired - Lifetime
  • 2006-07-04 CN CN2006800361893A patent/CN101278369B/zh not_active Expired - Fee Related
  • 2006-07-04 DE DE502006006665T patent/DE502006006665D1/de active Active
  • 2006-07-04 AT AT08018404T patent/ATE463833T1/de active
  • 2006-07-04 EP EP08018404A patent/EP2051275B1/fr not_active Not-in-force
  • 2006-07-04 EP EP06777558A patent/EP1911059B1/fr not_active Not-in-force
  • 2006-07-04 WO PCT/EP2006/063823 patent/WO2007014816A1/fr active Application Filing

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events