MXPA06007568A - Overvoltage protection device with improved follow current interrupting capacity - Google Patents

Abstract

The invention relates to a device (1) which is used to protect electrical equipment against transient overvoltages, comprising (i) a spark gap having an intrinsic follow current interrupting capacity and (ii) an element (5) for improving the follow current interrupting power, which co-operates with the spark gap (2) such that the resulting follow current interrupting capacity of the protective device (1) is essentially greater than the aforementioned intrinsic capacity. The invention is characterised in that, when the equipment has a suspected short-circuit current that exceeds the intrinsic interrupting capacity of the spark gap (2), the improving element (5) comprises a means (6) for limiting the intensity of the electric current that can pass through the spark gap (2), said limiting means (6) being specifically designed and mounted in relation to the spark gap (2) in order to limit the intensity of the follow current, such that the follow current can be interrupted thanks to the intrinsic follow current interrupting capacity of the spark gap (2). The invention is suitable for overvoltage protection devices.

Description

PROTECTION DEVICE AGAINST OVERVOLTAGE WITH CAPACITY OF INTERRUPTION OF IMPROVED FOLLOWING CURRENT TECHNICAL FIELD The present invention is concerned with the general technical field of devices for protecting electrical equipment or installations such as electrical appliances, circuits or distribution networks, against possible brief alterations to their electric power supply. The present invention is more particularly concerned with a device for protecting electrical equipment against voltage disturbances such as sudden elevations, in particular those due to lightning. The present invention is concerned with a protective device to protect electrical equipment against transient elevations, the device comprises first a spark gap that has intrinsic ability to break the tracking current and secondly an element of improvement to improve energy In the case of a follow-up current breaking, such an element cooperates with the spark gap in such a way that the protective device has a resultant tracking current breaking capacity that is significantly greater than the intrinsic capacity. The invention is also concerned with a method for protecting electrical equipment against transient elevations in which the electrical equipment is connected to a protective device comprising first a spark arrester having intrinsic ability to break the tracking current and in Secondly, an element of improvement to improve the energy of breakdown tracking, such element cooperates with the spark gap in such a way. that the device has a following current breaking capacity that. is significantly greater than the intrinsic capacity. Finally, the invention is concerned with the use of limiting means for limiting the magnitude of the electric current as an improvement element to improve the current breaking power following a protective device to protect the electrical equipment against transient elevations, the device it comprises a spark arrester having an intrinsic ability to break the tracking current, the improvement element for improving the tracking current breaking energy cooperates with the spark arrester in such a way that the protective device exhibits a breaking capacity of resulting tracking current that is significantly greater than the intrinsic capacity.

BACKGROUND OF THE INVENTION Devices for protecting electrical equipment against sudden elevations, in particular transient elevations, are known and in wide use. Such devices are sometimes referred to as "for bumps" or "lightning rods" and serve to transport the lightning current to ground and possibly also to limit the voltage spikes of induced blows to levels that can be supported by the connected equipment. downstream of a protection device. Known lightning rods may be based on a variety of technologies, depending on the nature of the active protection element used. In particular, it is known that known lightning arresters use a spark gap, that is, they have as their own active protection element a device comprising two electrodes facing each other, one is electrically connected to the phase for protection while the another is electrically connected to earth. The electrodes are separated by an insulating zone, for example constituted by air or gas or a dielectric body. When a stroke generated by the arrival of the lightning current reaches a predetermined level, it forms an electric arc and is established between the electrodes, thereby creating a short circuit to transport the lightning current in time and as a result protect the connected equipment downstream of the lightning rod. However, the known spark arrester arresters have a major deficiency associated with an electric arc 'which is established between their electrodes. Once the lightning current has been transported to ground by the electric arc, the arc does not spontaneously extinguish and thus continues to carry current, known as "follow-up current" that is taken from the installation for protection. The monitoring current must be interrupted in order to restore the normal operation of the installation and in particular in order to avoid any uncontrolled heating of the lightning conductor. The tracking current could naturally be interrupted by a general switch element of the network such as a circuit breaker. However, the use of such a general switch element to break the tracking current puts the network out of operation. Accordingly, it is preferable that the arrester itself be able to break the tracking current without causing the switch element to open. By their very construction, known spark arresters present a "natural" ability to break the current of tracking. This intrinsic ability to break the tracking current corresponds to the magnitude of maximum current that the spark arrester can extinguish on its own, due to its own characteristics alone. However, this "natural" ability to break the current is not generally sufficient to handle the actual operating conditions that can involve relatively large magnitude tracking currents. This is why several means have been used in the prior art to increase the breaking capacity of spark arresters. For example, known spark arresters have thus been provided with interrupter chambers, allowing the electric arc to be sub-divided to make it easier to extinguish it or of course they are air circulation systems which serve to obtain the same function. However, such additional means for increasing the throughput capacity are in general extremely difficult to implement, in particular because they can have a strong negative influence on the ability to carry lightning current, although this ability to carry the lightning current is specifically the primary function of a spark gap. In addition to the fact that such means for improving the breaking capacity tend to degrade the current carrying capacity of the spark gap, they are also generally expensive, bulky and difficult to manufacture.

BRIEF DESCRIPTION OF THE INVENTION Accordingly, the object given to the invention consequently seeks to provide a remedy to the various deficiencies mentioned above of the prior art and propose a new device to protect the electrical equipment against transient shocks, such a device is simple in design and has improved ability to break the tracking current, while retaining good capacity to carry the lightning current. - Another object of the invention seeks to propose a new device, to protect the electrical equipment against transient shocks that is of construction that is, particularly simple and not expensive. Another object of the invention seeks to propose a new device to protect the electrical equipment against transient shocks that present an excellent intermediate solution between voltage protection and ability to break current tracking. Another object of the invention seeks to propose a new device for protecting the electrical device against transient shocks that implement standard electrical components. Another object of the invention seeks to propose a new device to protect electrical equipment against transient shocks that is compact and very easy and fast to manufacture. Another object of the invention seeks to propose a new method for protecting electrical equipment against transient blows that is particularly effective and reliable. Another object of the invention seeks to propose a new method for protecting electrical equipment against transient shocks that is particularly simple to implement. Another object of the invention seeks to propose a new method to protect the equipment -electric against transient blows that is not expensive. Another object of the invention seeks to provide a new use of means to limit the magnitude of an electric current that allows the production of electrical equipment against transient hits to be improved. The objects given to the invention are obtained with the aid of a protective device to protect the electrical equipment against transient shocks, the device comprises first of all a spark gap that has intrinsic ability to break the tracking current and secondly an element of improvement to improve the tracking current breaking energy, such element cooperates with the spark gap in such a way that the protective device has a current breaking capacity that is significantly greater than the intrinsic capacity, the device is characterized in that the equipment has a putative short-circuit current that exceeds the intrinsic breaking capacity of the spark gap, the improvement element comprises limiter means for limiting the magnitude of the electric current passing through the spark gap, the means of limiter are designed esp ecologically and connected in relation to the spark arrester to limit the magnitude of the tracking current in such a way that the tracking current can be interrupted by the. intrinsic tracking current breaking capacity of the spark gap only. The objects given to the invention are also obtained with the aid of a method for protecting electrical equipment against transient shocks in which the electrical equipment is connected to a protective device comprising first of all a spark gap that has intrinsic ability to break the follow-up current and secondly an improvement element to improve the tracking current breaking power, such element cooperates with the spark gap in such a way that the device has resultant tracking current breaking capacity which is significantly higher than the intrinsic capacity, the method is characterized in that the equipment has an assumed short circuit current that exceeds the intrinsic rupture capacity of the spark gap, - the "improvement element" comprises limiter means for limiting the magnitude of the electric current passing through the spark gap, the limiter means are also specifically designed and connected in relation to the spark gap to limit the magnitude of the tracking current in such a way that the following current can be interrupted by the intrinsic tracking current breaking capacity of the spark arrester alone. The objects given to the invention are also obtained with the help of the use of limiter means to limit the magnitude of the electric current as an improvement element to improve the current breaking power of a protective device to protect the equipment electrical against transient shocks, the device comprises a spark arrester having an intrinsic ability to break the tracking current, the improvement element for improving the current breaking power of the co-operates with the spark arrester in such a way that the device protector has a resultant tracking current breaking capacity that is significantly greater than the intrinsic capacity, the use is characterized in that the equipment having a putative short circuit current exceeding the intrinsic rupture capacity of the spark gap, the limiter means - they are designed specifically and connected in relation to the spark arrester to limit the magnitude of the tracking current passing through the spark gap, such that the tracking current can be interrupted by the intrinsic tracking current breaking capacity of the spark gap. spark discharger alone.

BRIEF DESCRIPTION OF THE FIGURES Other objects and advantages of the invention will appear in greater detail in the reading of the following description with reference to the. attached figures given as illustrative non-limiting examples and in which: Figure 1 is a schematic view of a first variant embodiment of a protective device according to the invention. Figure 2 is a schematic view of a second variant embodiment of a protective device according to the invention.

BEST MODE FOR CARRYING OUT THE INVENTION Figures 1 and 2 show a device 1, 10 for protecting the electrical equipment against shocks or pulses of current, in particular against transient voltage pulses of the type generated by a lightning strike. The term "electrical equipment" is used herein to refer to any type of apparatus, instrument, installation, network, electrical circuit or telecommunications circuit that could be subjected to uncertainties of electrical power sources from the point of view of voltage and in particular to pulsations or blows due to lightning. As is well known to the person skilled in the art, the electrical equipment for protection has a short-circuit current, assumed to correspond to a given electrical current alue which is known (or may be known) to the person skilled in the art. . The pulsation protective device 1, 10 according to the invention advantageously constitutes a lightning conductor. According to the invention, the device 1, 10 comprises a lightning conductor cell specifically constituted by a spark gap 2, 20. The spark gap 2, 20 implemented in the context of the invention can be of any known type, for the a person skilled in the art and for example may be constituted by a spark gap filled with air or a spark gap filled with gas. The invention is not absolutely limited to any particular type of spark arrestor and any type of spark arrestor well known to the person skilled in the art could be used. Conventionally, the spark arrester 2, 20 comprises a first electrode 2A, 20A electrically connected to the phase 3, 30 for protection, together with. a second electrode 2B, 20B for electrically connecting to ground 4, 40. Without going beyond the scope of the invention, it is also possible to contemplate that, instead of being connected in parallel between a phase 3, 30 and earth 4, 40, the spark arrester 2, 20 could be connected between neutral and earth or between a phase and neutral or of course between two faeces (differential protection). • Preferably, the spark arrester 2, 20 constitutes the only active component of the device 1, 10, it being understood that without going beyond the scope of the invention it is possible to contemplate that the spark arrester 2, 20 is associated with other non-linear components , whether or not they are constituted by spark arresters. Conventionally, the spark arrester 2, 20 has an intrinsic ability to break the tracking current. This intrinsic ability to break the follow-up current corresponds to the magnitude of the maximum current that the spark gap 2, 20 is capable of breaking by itself, that is, only due to its construction of two electrodes separated by an insulating zone and without the help of additional devices. This "natural" breaking capacity results in particular from the relative shape of the various elements that make up the spark gap 2, 20, the materials selected to manufacture the elements and the dimensioning of the elements. According to the invention, the protective device 1, 10 also includes an improvement element 5, 50 to improve its tracking current breaking power, the element 5, 50 cooperates with the spark gap 2, 20 in such a way that the device 1, 10 'has a resultant capacity to break the tracking current which is significantly greater than the intrinsic capacity of the spark arrester: -, spark 2, 20 by itself to break the tracking current. Thus, the enhancement element 5, 50 allows the magnitude of the tracking current that the device 1, 10 is able to break after lightning current has been transported to be increased compared to a device comprising the surge arrester. spark 2, 20 by itself. According to an important characteristic of the "invention, the improvement element 5, 50 comprises limiting means 6, 60 to limit the magnitude of the electric current passing through the spark gap 2, 20 and in particular to limit the magnitude of the tracking current. The term "limit" is used herein to specify the ability to oppose the passage of electric current that leads to the magnitude of the electric current to be decreased such that its value is less than the value it would have in the absence of the means of limiter 6, 60. Thus, the tracking current that is "perceived" by the lightning arrester 1, 10 is smaller than the assumed short-circuit current of the installation for protection, due to the presence of the limiting means 6, 60. Thus, this technical arrangement allows a lightning arrester-spark arrester to be installed in a facility whose assumed short-circuit current exceeds the intrinsic capacity of the spark arrester. 2, 20 to break the tracking current. The assembly constituted by the spark arrester 2, 20 and the limiter means 6, 60 - behaves as well as a lightning arrester with high breaking capacity, but without necessarily requiring the implementation of a switch chamber or any other means of switches conventional (hydrogen degassing plastic material, air circulation). Thus, the general principle of the invention depends on implementing a "decoding" that artificially reduces the magnitude of the tracking current carried by the spark gap 2, 20, so that the current can be interrupted only by the breaking capacity of intrinsic tracking current of the spark arrester 2, 20. The improvement element 5, 50 is thus specifically designed and connected in relation to the spark gap 2, 20, to limit the magnitude of the tracking current to a value which is lower than the assumed short-circuit current of the installation for protection, the value is compatible * with the extinguishing power of the spark arrester. In other words, the invention advantageously consists of :, firstly protecting the equipment by means of a spark gap 2, 20 having intrinsic ability to break the follow-up current which is less than the short-circuit current. installation; this means that although the spark arrester has a good capacity to carry the lightning current, it is not capable by itself of breaking the follow-up current since its intrinsic breaking capacity is too small compared to the monitoring current which is likely to be carried by the equipment, and - secondly, to remedy the insufficient tracking current breaking capacity mentioned above by functionally associating the spark arrester 2, 20 with limiter means 6, 60 to limit the magnitude of the electrical current that passes through the spark arrester, such that • after a transient pulsation, the spark arrester does not carry the short-circuit current of the equipment, but a current that is smaller than the short-circuit current and that is sufficiently small in such a way that it is possible for the spark arrestor to break exclusively by itself, this is indicates that the limiting means 6, 60 are designed (and in particular dimensioned) as a function of the putative short-circuit current of the equipment, such that the tracking current passing through the spark gap is smaller than the capacity of the spark arrester. intrinsic breakdown of the spark arrester. Thus, the invention makes it possible in a simple and not expensive way to overcome the inherent conflict of any spark gap between high capacity to carry lightning current and high capacity to break the tracking current. When selecting a spark arrester with low current breaking capacity, that is, preferably less than the assumed short circuit current of the protection equipment, the invention makes it possible in response to benefit from the high capacity to carry current, with the low breaking capacity of the spark gap that is corrected by means of implementation of the means of limiter. Advantageously, the improvement element 5, 50 comprises as its means for limiting the current a resistive element 9, 90, preferably a linear resistive element. This resistive element 9, 90 is preferably connected in series with the spark arrester 2, 20. The term "resistive" must be understood in its broadest sense, that is, it refers to both the resistive behavior when it is supplied with direct current ( DC) and with impedance behavior when it is supplied with alternating current (AC). More particularly and as shown in Figures 1 and 2, the element, resistive 9, 90, has a first terminal 7, 70 electrically connected to the first electrodes 2A, 20A of the spark gap 2, 20 and a second terminal 8. , 80, electrically connected to phase 3, 30 for protection. The sub-assembly constituted by the serial connection of the resistive element 9, 90 and the spark arrester 2, 20 is thus connected in parallel between the phase 3, 30 and earth 4, 40. Advantageously, the resistive element 9, 90 does not it presents substantially self-inductance, that is, it does not substantially generate any inductance effect or generates induction effects that are as small as possible or negligible in comparison with the selected resistance value. In other words, for a given resistance value (in ohms) for element 9, 90, must be formed to significantly limit any induction effects. For this purpose, the resistive element 9, 90 is preferably solid and compact and does not form a loop or a winding or a helix. This technical arrangement allows the device 1, 10 according to the invention avoid generating any additional stroke or pulsation when passing the lightning current. As a result, the level of voltage protection provided by the device 1, 10 is not degraded compared to that of a device comprising the spark gap 2, 20 by itself without the improvement element 5, 50. The connection substantially non-inductive of the resistive element 9, 90 in series with the spark arrester 2, 20 thus makes it possible in a very simple manner to significantly increase the tracking current breaking capacity of the device 1, 10 compared to a device comprising the arrester of spark 2, 20 by itself, but without that having a negative influence on the ability of the spark arrester 2, 20 to carry the lightning current, as would be the case for example with a conventional interrupter chamber. Independently, the invention is also concerned with a protective device 1, 10 for protecting electrical equipment against transient pulsations or shocks and comprising first of all a spark gap 2, 20 having an intrinsic ability to break the follow-on current and secondly an improvement element 5, 50 for improving the tracking current breaking power, such element 'cooperates with the spark discharge 2, 20' in such a way that the device 1, 10 presents a resulting capacity to break the tracking current which is substantially greater than the intrinsic capacity, the improvement element 5, 50 comprises limiting means 6, 60 for limiting the magnitude of the electric current passing through the spark arrester 2, 20, the means of limiter 6, 60 comprise by themselves a resistive element 9, 90 connected in series with the spark arrester 2, 20, the resistive element is of substantially non-inductive nature. In the first variant mode, shown in the Figure 1, the resistive element is advantageously formed by an electrical resistor 9, that is, by a single linear electrical component which can be identified as such and is characterized essentially by its ability to limit the current flowing in a circuit in a way that it is substantially constant, predetermined and known. In the variant shown in Figure 2, the protective device 1, 10 according to the invention comprises electrical connection means of the spark gap 2, 20 to connect it to the electrical equipment for protection 3, 30, 4, 40, the means of connection directly constitute the resistive element 90, thereby eliminating any need to connect an additional separate electrical component. In particular the material (s) from which the connecting means are manufactured and also the dimensions of the connecting means (in particular in terms of cross-section) are selected from such that the connection means carry out the function of limiting the magnitude of the electric current that is sought in the context of the present invention. Preferably, the connecting element for connecting the first electrode 20A to the protection phase 30 is designed to act exclusively as the protection element 50. The Applicant has discovered that a resistive element of low resistance is sufficient to obtain a technical effect. significant. As an example, for an installation energized at 230 volts (V) and 25 kiloamperes (kA), an appreciable result can be obtained with a resistive element that has a resistance of a few milliohms (mO), that is, it falls in the range of 10 mO to 50 mO. More generally, the resistive element must be selected as a function of the assumed short-circuit current of the installation and the intrinsic capacity of the spark arrester proposed to break the follow-up current Advantageously, the improvement element 5, 50 is constituted exclusively by the resistive element 9, 90 regardless of whether it is based on components having electrical resistance or based directly on connection means designed specifically for this purpose.The effect of improving the breaking power is thus obtained substantially exclusively by the spark discharger 2, 20 which is connected in series with a resistive element 9, 90. However, without going beyond the scope of the invention, it is entirely possible to contemplate the improvement element 5, 50 which further comprises, in addition to the - limiting means "6, 60 conventional means of the switch chamber class, for example. Under such circumstances, the intrinsic ability to break the follow-up current will correspond to the breaking capacity of the sub-assembly constituted by the spark gap 2, 20 and the conventional means if they are of the kind of a switch chamber or of some other kind. The limiter means 6, 60 serve to further improve that intrinsic capacity, even if it is already greater than the capacity of a spark gap 2, 20 "alone", that is, without any additional arc extinguishing means. The invention also provides a method for improving the tracking current breaking capacity of a device 1, 10 to protect electrical equipment against pulsations or shocks such as a lightning rod, the device includes a spark arrester 2, 20. According to an important feature of the invention, the method according to the invention comprises an improvement step in which the device 1, 10 is provided with limiter means 6, 60 to limit the magnitude of the electric current passing through the arrester of spark 2, 20 and in particular the tracking current that occurs after carrying lightning current. During the improvement step, a resistive element 9, 90 is advantageously connected in series with the spark arrester 2, 20. In a first variant implementation of the method according to the invention, the resistive element 9 is formed by a electrical resistor, as described above. In a second variant, the method comprises a step in which the spark arrester 2, 20 is connected to the equipment for protection by electrical connection means, the connection means being specifically designed to directly form the resistive element 90 again as shown in FIG. describe above. The method according to the invention thus makes it possible to simply and quickly improve the breaking capacity of any spark arrester arrester in existence in the market only by adding selected resistive means as a function of the intrinsic breaking capacity of the spark arrester. spark and of the supposed short circuit current of the installation to be protected. The invention also provides a method for protecting electrical equipment against transient pulsations in which the electrical equipment is functionally connected with a protective device 1, 10 comprising first of all a spark gap 2, 20 having an intrinsic ability to break the current of tracking and secondly an element of improvement 5, 50 to improve the breaking power of the tracking current, such element cooperates with the spark gap 2, 20 in such a way that the device 1, 10 has a resulting capacity to break the tracking current that is substantially greater than the intrinsic capacity. In this method, the equipment has an assumed short circuit current that exceeds the intrinsic breaking capacity of the spark gap 2, 20. In other words, the intrinsic breaking capacity of the spark gap 2, 20 is significantly lower than the short circuit current assumed of the equipment for protection. According to the method of protection of the invention, the improvement element 5, 50 comprises limiting means 6, 60 for limiting the magnitude of the electric current passing through the spark gap 2, 20, the limiter means 6, 60 are specifically designed and connected in relation to. the spark arrester 2, 20 to limit the magnitude of the tracking current, such that the tracking current can be interrupted only by the intrinsic capacity of the spark arrester 2, 20 to break the tracking current.

Advantageously, improvement element 5, 50 comprises as its limiting means a resistive element 9,90 connected in series with the spark gap 2, 20. The resistive element 9, -90 is preferably constituted by an electrical resistor 9. Advantageously, the spark plug discharger 2, 20 connected to the equipment by electrical connection means, the electrical connection means form the resistive element 90. Finally, the invention is also concerned with the use of limiter means of the electrical resistor class to limit the magnitude of an electric current, such as an enhancement element to improve the current breaking power of a device, of the class of lightning rods, to protect the electrical equipment against pulsations, such device comprises a spark gap discharger discharger that has intrinsic capacity to break the tracking current, in such a way that the device presents a resulting capacity to break the current of tracking that is greater than the capacity - intrinsic. - More precisely, the invention is concerned with the use of limiter means 3, 60 for limiting the magnitude of the electric current as an improvement element 5, 50 for improving the breaking capacity of tracking support of a device 1, 10. to protect the electrical equipment against transient pulsations, the device 1, 10 comprises a spark arrester 2, 20 having intrinsic ability to break the tracking current, the improvement element 5, 50 to improve the breaking power of the tracking current cooperates with the spark arrester 2, 20 in such a way that the protection device 1, 10 has a resultant tracking current capacity that is significantly greater than the intrinsic capacity, the use is characterized in that the equipment having a short circuit current assumed to exceed the intrinsic breaking capacity of the spark arrester 2, 20 the limiter means 3, 60 are designed specifically and connected in connection with spark arrester 2, 20 to limit the magnitude of the tracking current passing through the spark arrester 2, 20 such that the tracking current can be interrupted by the breaking capacity of intrinsic tracking current of gut space 2, 20 only. Thus, the invention seeks in particular to provide a new use of electrical chip components known as components for increasing the current breaking capacity of the known standard spark gap tracker. Finally, the invention makes it possible in a simple but significant way to improve the breaking power of any known device subject to the tracking current phenomenon, while providing good production against transient pulsations.

POSSIBILITY OF INDUSTRIAL APPLICATION The industrial application of the invention lies in the design, manufacture and use of a protective device to provide protection against transient pulsations.

Claims (12)

1. .CLAIMS 1. A protective device to protect electrical equipment against transient pulsations, the device is characterized because it comprises: first a spark gap that has intrinsic capacity to break the current of tracking and secondly an element of improvement to improve the trailing current breaking power, the element cooperates with the spark gap in such a way that the protective device has a resultant tracking current breaking capacity that is significantly greater than the intrinsic capacity, the device is characterized in that the equipment that presents an opposite short circuit current exceeds the intrinsic breaking capacity of the spark gap, the enhancement element comprises limiter means for limiting the magnitude of the electric current passing through the spark gap, the limiter means are specifically designed and connected in relationship with the spark gap to limit the magnitude of the tracking current such that the tracking current can be interrupted by the intrinsic tracking current breaking capacity of the spark gap alone. The device according to claim 1, characterized in that the improvement element comprises a resistive element connected e? series with the spark arrestor. 3. The device according to claim 1, characterized in that the resistive element has substantially no self-induction. 4. The device according to claim 2 or claim 3, characterized in that the resistive element is formed by an electrical resistor. The device according to claim 2 or claim 3, characterized in that it includes electrical connection means to connect the spark gap to the electrical equipment, the connection means form the resistive element: 6. The device according to any of claims 2 to 5, characterized in that the improvement element is constituted exclusively by the resistive element. The device according to any of claims 1 to 6, characterized in that it constructs a lightning conductor. > 8. One method. to protect electrical equipment against transient pulsations in which the electrical equipment is connected to a protective device that comprises first of all a spark gap that has intrinsic capacity to break the current of tracking and secondly an element of improvement to improve the tracking current breaking power, the element cooperates with the spark gap in such a way that the device has a resultant leakage current breaking capacity which is significantly greater than the intrinsic capacity, the method is characterized in that the The equipment has a putative short-circuit current that exceeds the intrinsic breaking capacity of the spark gap, the improving element comprises limiting means for limiting the magnitude of the electric current passing through the spark gap, the limiting means is specifically designed and connected in relation n with the spark gap for limiting the magnitude of the current monitoring so that the current can be interrupted by monitoring the current breaking capability of monitoring intrinsic spark gap only. The method according to claim 8, characterized in that the improvement element comprises a resistive element connected in series with the spark gap. 10. The method according to claim 9, characterized in that the resistive element is formed by an electrical resistor. The method according to claim 9, characterized in that the spark gap is connected to the equipment by means of electrical connection, the connecting means form the resistive element. 12. The use of limiter means for limiting the magnitude of the electric current as an improvement element for improving the current breaking power of a protective device to protect the electrical equipment against transient pulsations, the device comprises a spacing of spark having an intrinsic ability to break the tracking current, the improvement element for improving the breaking power of the tracking current cooperates with the spark gap, such that the protective device has a current breaking capacity of resulting tracking which is significantly greater than the intrinsic capacity, the use is characterized in that the equipment having a putative short circuit current exceeding the intrinsic breaking capacity of the spark gap, the limiter means are specifically designed and connected in relation to the spark arrestor for l mimic the magnitude of the tracking current passing through the spark gap in such a manner that the following current can be interrupted by the intrinsic tracking current breaking capacity of the spark gap alone. SUMMARY OF THE INVENTION The invention is concerned with a protective device to protect the electrical equipment against pulsations-transients, the device comprises first of all a spark arrester (2, 20) that has intrinsic capacity to break the tracking current and secondly place an improvement element (5, 50) to improve the tracking current breaking power, the element cooperates with the spark gap (2, 20) in such a way that the protective device (1, 10) has a capacity of resulting current breaking that is significantly greater than the intrinsic capacity, the device is characterized in that the equipment having a putative short circuit current exceeding the intrinsic rupture capacity of the spark gap (2, 20), the element of improvement (5, 50) comprises limiter means (6, 60) to limit the magnitude of the electric current passing through the space When the spark arrester (2, 20) is present, the limiter means (6, 60) is specifically designed and connected in relation to the spark arrester '(2, 20) to limit the magnitude of the tracking current in such a manner. that the tracking current can be interrupted by the intrinsic tracking current breaking capacity of the spark gap (2, 20) alone. Devices are provided to provide protection against pulsations.