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
  • H01T1/16—Series resistor structurally associated with spark gap
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
  • H02H9/00—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection
  • H02H9/04—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess voltage
  • H02H9/06—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess voltage using spark-gap arresters

Definitions

• the present invention relates to the general technical field of devices for protecting electrical equipment or installations, such as electrical appliances, circuits or distribution networks, against disturbances, possibly momentary, of electrical supply.
• the present invention relates more particularly to a device for protecting electrical equipment against voltage disturbances, such as overvoltages, in particular due to lightning.
• the present invention relates to a device for protecting electrical equipment against transient overvoltages comprising, on the one hand, a spark gap having an intrinsic current breaking capacity and, on the other hand, a device for improving the current breaking capacity of suite which cooperates with the spark gap so that the protection device has a resultant capacity for immediate power cut which is substantially greater than said intrinsic capacity.
• the invention also relates to a method of protecting electrical equipment against transient overvoltages in which the electrical equipment is connected to a protection device comprising on the one hand a spark gap having an intrinsic current cut-off capacity, and d on the other hand, a device for improving the power cut-off power immediately, which cooperates with the spark gap so that the device has a resultant immediate power cut capacity which is significantly greater than said intrinsic capacity.
• the invention relates to the use of a means for limiting the intensity of electric current as a means of improving the power cut-off power following a device for protecting electrical equipment against transient overvoltages, said device comprising a spark gap having an intrinsic current breaking capacity, the member for improving the breaking current breaking power cooperating with the spark gap so that the protection device has a resulting breaking capacity of consecutive current which is significantly greater than said intrinsic capacity.
• Such devices which are sometimes referred to as “surge protectors” or “surge arresters”, are intended to drain lightning currents to the ground, and possibly to clip induced overvoltages at levels compatible with the resistance of equipment and materials connected downstream of protection devices.
• Known surge arresters can be based on different technologies, depending on the nature of the active protective element that they use.
• spark arrester that is to say using, as active protection element, a device comprising two electrodes placed opposite, one being electrically connected to the phase to protect, while the other is electrically connected to earth.
• the electrodes are separated by an insulating zone, formed for example by an air space, a gas space or a dielectric body.
• This current must be interrupted in order to restore normal operation of the installation and in particular to avoid any uncontrolled overheating of the arrester.
• the immediate current cut can of course be carried out by a general cut-off member of the network, such as a circuit breaker.
• a general cut-off member of the network such as a circuit breaker.
• the use of such a general cut-off device to cut the current immediately causes the network to be put out of service.
• the object assigned to the invention therefore aims to remedy the various drawbacks of the prior art mentioned above, and to propose a new device for protecting electrical equipment against transient overvoltages, of simple design and which has a improved immediate power cut capacity, while retaining good lightning current flow capacity.
• Another object of the invention aims to protect a new device for protecting electrical equipment against transient overvoltages of particularly simple and inexpensive construction.
• Another object of the invention is to propose a new device for protecting electrical equipment against transient overvoltages having an excellent compromise between voltage protection and current breaking capacity.
• Another object of the invention is to propose a new device for protecting electrical equipment against transient overvoltages using standard electrical components.
• Another object of the invention is to propose a new device for protecting electrical equipment against transient overvoltages of reduced size and very easy and quick to manufacture.
• Another object of the invention is to propose a new method for protecting electrical equipment against transient overvoltages which is particularly efficient and reliable.
• Another object of the invention is to propose a new method of protecting electrical equipment against transient overvoltages which is particularly simple to implement.
• Another object of the invention is to propose a new method of protecting electrical equipment against inexpensive transient overvoltages.
• Another object of the invention aims to propose a new use of a current intensity limiting means making it possible to improve the protection of electrical equipment against transient overvoltages.
• a device for protecting electrical equipment against transient overvoltages comprising, on the one hand, a spark gap having an intrinsic current cut-off capacity and, on the other hand, a organ for improving the immediate current cutoff power which cooperates with the spark gap so that the protection device has a resultant current cutoff capacity which is substantially greater than said intrinsic capacity, characterized in that , the equipment having a presumed short-circuit current which exceeds said intrinsic breaking capacity of the spark gap, the improvement member comprises means for limiting the intensity of the electric current capable of passing through the spark gap, said limiting means being specifically designed and mounted relative to the spark gap to limit the intensity of the current immediately after such a spell e that said follow-on current can be cut by virtue of the intrinsic capacity for following current cut-off of the spark gap.
• the objects assigned to the invention are also achieved using a method of protecting electrical equipment against transient overvoltages in which electrical equipment is connected to a protection device comprising on the one hand a spark gap having a intrinsic capacity for immediate power failure, and on the other hand a device for improving the power for immediate power interruption which cooperates with the spark gap so that the device has a resulting capacity for immediate power interruption which is substantially greater than said intrinsic capacity, characterized in that, the equipment having a presumed short-circuit current which exceeds said intrinsic breaking capacity of the spark gap, the improvement member comprises a means of limitation of the intensity of the electric current likely to pass through the spark gap, said limiting means being specifically designed and mounted relative to the spark gap to limit the intensity of the follow-on current so that said follow-up current can be cut by to the intrinsic capacity of the spark gap following power failure.
• the objects assigned to the invention are also achieved by using a means for limiting the intensity of electric current as a device for improving the current breaking capacity of a device.
• said device comprising a spark gap having an intrinsic capacity to immediately cut current, the means for improving the power to cut current immediately cooperating with the spark so that that the protection device has a resultant immediate current cut-off capacity which is substantially greater than said intrinsic capacity, characterized in that, the equipment having a presumed short-circuit current which exceeds said intrinsic cut-off capacity spark gap, the limiting means is specifically designed and mounted relative to the spark gap to limit the intensity of the following current e capable of passing through the spark gap so that said follow-up current can be cut thanks to the only intrinsic current cut-off capacity of the spark gap.
• FIG. 1 illustrates, in a schematic view, a first variant of realization of a protection device according to the invention.
• FIG. 2 illustrates, in a schematic view, a second alternative embodiment of a protection device according to the invention.
• Figures 1 and 2 show a device 1, 10 for protecting electrical equipment against overvoltages, and in particular against transient overvoltages of the type generated by a lightning strike.
• electrical equipment is meant here any type of apparatus, instrument, installation, network, electrical or telecommunications circuit liable to be subject to electrical supply hazards from the point of view of voltage, and in particular to lightning surges.
• the electrical equipment to be protected has, as is well known to a person skilled in the art, a presumed short-circuit current, which corresponds to a given value of electrical intensity known (or which may be) by the skilled in the art.
• the device 1, 10 for protection against overvoltages according to the invention advantageously constitutes a surge arrester.
• the device 1, 10 comprises a lightning arrester cell formed in this case by a spark gap 2, 20.
• the spark gap 2, 20 implemented in the context of the invention may be of any known type of those skilled in the art, and for example be constituted by an air or gas spark gap.
• the invention is absolutely not limited to a particular type of spark gap, and any type of spark gap well known to those skilled in the art may be used.
• the spark gap 2, 20 comprises a first electrode 2A, 20A electrically connected to the phase 3, 30 to be protected, as well as a second electrode 2B, 20B intended to be electrically connected to the ground 4, 40. It is also conceivable, without departing from the scope of the invention, that the spark gap 2, 20, instead of being connected in bypass between a phase 3, 30 and the earth 4, 40, be connected between the neutral and earth, between phase and neutral or between two phases (case of differential protection).
• the spark gap 2, 20 constitutes the single active component of the device 1, 10, it being understood that it is conceivable, without departing from the scope of the invention, that said spark gap 2, 20 can be associated with other non-linear components, whether or not made up of spark gaps.
• the spark gap 2, 20 has, in a conventional manner, an intrinsic current cut-off capacity.
• This intrinsic current breaking capacity corresponds to the maximum current intensity that the spark gap 2, 20 is able to cut by itself, that is to say by the simple fact of its construction with two electrodes separated by an insulating zone, without the aid of additional devices.
• This “natural” breaking capacity results in particular from the relative conformation of the various elements forming the spark gap 2, 20, from the materials chosen for the production of said elements, as well as from the dimensioning of said elements.
• the protection device 1, 10 also comprises a member 5, 50 for improving the power cut-off power immediately, said member 5, 50 cooperating with the spark gap 2, 20 so that the device 1, 10 has a resultant current cut-off capacity of continuation which is substantially greater than the intrinsic current cutoff capacity of the spark gap 2, 20 taken alone.
• the improvement member 5, 50 thus makes it possible to increase the current intensity immediately that the device 1, 10 is able to cut off after the lightning current has flowed, relative to a device which would comprise only the spark gap 2, 20.
• the improvement member 5, 50 comprises a means 6, 60 for limiting the intensity of the electric current capable of passing through the spark gap 2, 20, and in particular of the following current. .
• limitation is meant here a faculty of opposition to the passage of electric current which leads to a reduction in the intensity of electric current, the value of which is thus lower than the value it would have reached in the absence of the means limitation 6, 60.
• the current "perceived" by the surge arrester 1, 10 will be lower than the presumed short-circuit current of the installation to be protected, thanks to the presence of the limiting means 6, 60.
• This technical provision therefore authorizes the installation of a spark arrester in an installation whose presumed short-circuit current exceeds the intrinsic current breaking capacity of spark gap 2, 20.
• the assembly formed by the spark gap 2, 20 and the limiting means 6, 60 will therefore behave like a surge arrester with high breaking capacity, without necessarily needing to require the use of a breaking chamber or any other conventional complex means (plastic degassing hydrogen, air circulation) of cutting.
• the general principle of the invention therefore rests on the implementation of a "decoy" which artificially reduces the intensity of the follow-on current flowing through the spark gap 2, 20, so that said current can be cut thanks to the only intrinsic current cut-off capacity of spark gap 2, 20.
• the improvement member 5, 50 is therefore specifically designed and mounted relative to the spark gap 2, 20 in order to limit the intensity of the current thereafter to a value lower than the presumed short-circuit current of the installation to protect, said value being compatible with the inherent extinguishing power of spark gap 2, 20 itself.
• the invention advantageously consists in:
• the invention thus makes it possible to overcome in a simple and inexpensive manner the inherent opposition to any spark gap between on the one hand a high lightning current flow capacity and on the other hand a high current breaking capacity.
• the invention by proposing to choose a spark gap with a low current cut-off capacity, that is to say preferably less than the presumed short-circuit current of the equipment to be protected, makes it possible to benefit in return from a high lightning current flow capacity, the low cut-off capacity of the spark gap being corrected by the use of the limiting means.
• the improvement member 5, 50 comprises, as a means for limiting intensity, a resistive element 9, 90, preferably linear.
• This resistive element 9, 90 is preferably mounted in series with the spark gap 2, 20.
• resistive must be taken here in its broadest sense, that is to say that it refers both to resistance behavior in the context of a DC power supply and to behavior impedance in an AC power supply.
• the resistive element 9, 90 has a first pole 7, 70 electrically connected to the first electrode 2A, 20A of the spark gap 2, 20, as well as a second pole 8, 80 electrically connected to phase 3, 30 to be protected.
• the subassembly constituted by the series connection of the resistive element 9, 90 and of the spark gap 2, 20 is thus connected in bypass between phase 3, 30 and the earth 4, 40.
• the resistive element 9, 90 has a substantially non-self-inductive nature, that is to say that it does not generate substantially inductance effects, or at least an inductance effect as small as possible, or negligible, compared to the resistance value chosen.
• the resistive element 9, 90 is preferably solid and compact, and does not form a loop, winding or helix.
• This technical arrangement allows the device 1, 10 according to the invention not to generate additional overvoltage during the passage of a lightning current. As a result, the level of voltage protection of the device 1, 10 is not degraded compared to that of a device which would only include the spark gap 2, 20, without the improvement member 5, 50.
• the mounting a resistive element 9, 90 substantially aselfic in series with the spark gap 2, 20 thus allows, in a very simple way, to significantly increase the power failure capacity immediately of the device 1, 10 compared to a device comprising only the spark gap 2, 20, without negatively influencing the lightning current flow characteristics of the spark gap 2, 20, as could for example be a conventional switching chamber.
• the invention moreover relates, independently, to a device 1, 10 for protecting electrical equipment against transient overvoltages comprising, on the one hand, a spark gap 2, 20 having an intrinsic current cut-off capacity, and d 'on the other hand an improvement member 5, 50 of the power of immediate power failure which cooperates with the spark gap 2, 20 so that the device 1, 10 has a resulting capacity of immediate power failure which is substantially greater than said intrinsic capacity, said improvement member 5, 50 comprising means limiting 6, 60 the intensity of the electric current capable of passing through the spark gap 2, 20, said limiting means 6, 60 itself comprising a resistive element 9, 90 mounted in series with the spark gap 2, 20, said resistive element having a substantially non-self-inducing character.
• the resistive element is advantageously formed by an electrical resistance 9, that is to say by a unitary linear electrical component, identifiable as such, characterized essentially by its ability to limit the current flowing in a circuit, in a substantially constant, predetermined and known manner.
• the protective device 1, 10 comprises means of electrical connection of the spark gap 2, 20 to the electrical equipment to be protected 3, 30, 4, 40, said connection means directly forming the resistive element 90, thereby eliminating the need to connect an additional separate electrical component.
• connection means In particular, the material or materials from which the connection means are made, as well as the dimensioning (in particular in terms of section) of said connection means will be chosen so that the connection means carry out the function of current intensity limitation electric sought in the context of the present invention.
• connection element allowing the connection of the first electrode 20A to the phase to be protected 30 will be designed to play exclusively the role of improvement member 50.
• a resistive element of low resistance is sufficient to obtain a significant technical effect.
• a resistive element whose resistance is a few milliohms, and for example between 10 and 50 milliohms made it possible to obtain an appreciable result.
• the resistive element must be chosen as a function of the presumed short-circuit current of the installation, and of the intrinsic current breaking capacity of the spark gap envisaged.
• the improvement member 5, 50 will be exclusively constituted by the resistive element 9, 90, whether the latter is made on the basis of electrical resistance components or directly using connection means specially designed for this purpose. .
• the improvement member 5, 50 also include, in addition to the limitation means 6, 60, conventional means, of the chamber type. cut for example.
• the intrinsic current breaking capacity will correspond here to the breaking capacity of the subassembly formed by the spark gap 2, 20 and said conventional means, of the breaking chamber or other type.
• the limiting means 6, 60 will further improve this intrinsic capacity, even if the latter is already greater than the capacity of a spark gap 2, 20 "alone", that is to say without any additional means of extinguishing d 'bow.
• the invention also relates to a method for improving the current cut-off capacity of an equipment protection device. electric against overvoltages 1, 10, of the arrester type, said device comprising a spark gap 2, 20.
• the method according to the invention comprises, according to an important characteristic of the invention, an improvement step in which the device 1, 10 is provided with means 6, 60 for limiting the intensity of the electric current capable of cross the spark gap 2, 20, in particular of the following current occurring after the flow of a lightning current.
• a resistive element 9, 90 is mounted in series with the spark gap 2, 20.
• the resistive element 9 is formed by an electrical resistance, as has been described above.
• the method comprises a step in which the spark gap 2, 20 is connected to the equipment to be protected using electrical connection means, said connection means being specially designed to directly form the resistive element 90, as described above.
• the process according to the invention thus makes it possible, in a simple and rapid manner, to improve the breaking capacity of any surge arrester with spark gap existing on the market, by the simple addition of a resistive means chosen as a function of the intrinsic capacity of cut-off of the spark gap, and of the presumed short-circuit current of the installation to be protected.
• the invention also relates to a method of protecting electrical equipment against transient overvoltages in which the electrical equipment is functionally connected to a protection device 1, 10 comprising, on the one hand, a spark gap 2, 20 having an intrinsic capacity for immediately following a power cut, and on the other hand, an improvement member 5, 50 for the following current cut power which cooperates with the spark gap 2, 20 so that the device 1, 10 has a resulting capacity for immediate power cut which is substantially greater than said intrinsic capacity.
• the equipment has a presumed short-circuit current which exceeds the intrinsic breaking capacity of the spark gap 2, 20.
• the intrinsic breaking capacity of the spark gap 2, 20 is substantially lower than the presumed short-circuit current of the equipment to be protected.
• the improvement member 5, 50 comprises a means of limiting 6, 60 of the intensity of the electric current capable of passing through the spark gap 2, 20, said limiting means 6, 60 being specifically designed and mounted relative to the spark gap 2, 20 to limit the intensity of the follow-on current so that said follow-up current can be cut off by virtue of the intrinsic current-breaking capacity alone of the spark-gap 2, 20.
• the improvement member 5, 50 comprises, as a limiting means, a resistive element 9, 90 mounted in series with the spark gap 2, 20.
• the resistive element 9, 90 is formed by an electrical resistance 9.
• the spark gap 2, 20 is connected to the equipment using electrical connection means, said connection means forming the resistive element 90.
• the invention also relates to the use of a means of limiting the intensity of electric current, of the electric resistance type, as a means of improving the power cut-off power following a protection device. of electrical equipment against overvoltages, of the lightning arrester type, which comprises a spark gap having an intrinsic capacity for immediate power cut, so that said device has a resultant capacity for immediate power cut greater than said intrinsic capacity.
• the invention relates to the use of a means 6, 60 for limiting the intensity of electric current as a means of improving 5, 50 of the power cut-off power following a protection device 1 , 10 of electrical equipment against transient overvoltages, said device 1, 10 comprising a spark gap 2, 20 having an intrinsic capacity to immediately cut current, the improvement member 5, 50 of the power to cut current immediately cooperating with the spark gap 2, 20 so that the protection device 1, 10 has a resultant immediate power cut capacity which is substantially greater than said intrinsic capacity, characterized in that, the equipment having a current suspected short circuit which exceeds said intrinsic breaking capacity of spark gap 2, 20, the limiting means 6, 60 is specifically designed and mounted relative to spark gap 2, 20 for li mimic the intensity of the follow-on current likely to pass through the spark gap 2, 20 so that said follow-up current can be cut thanks to the only intrinsic current cut-off capacity of the spark gap 2, 20.
• the invention therefore relates in particular to a new use of known electrical resistance components as components making it possible to increase the current breaking capacity following known standard spark gaps.
• the invention makes it possible to improve, in a simple but significant way, the breaking capacity of any known material subject to the phenomenon of current on, while allowing optimal protection against transient overvoltages.
• the invention finds its industrial application in the design, manufacture and use of protection devices against transient overvoltages.

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• 2003
  • 2003-12-30 FR FR0315576A patent/FR2864714B1/fr not_active Expired - Fee Related
• 2004
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