EP1329005B1 - Surge protection filter and lightning conductor system - Google Patents

Abstract

The system ( 1 ) is installed in a coaxial line for the transmission of high-frequency signals. It serves for the purpose of protecting apparatus or installations against electromagnetic pulses, overvoltages and/or lightning strokes. The system ( 1 ) comprises shortcircuit lines ( 5, 6 ), which are disposed approximately parallel to the inner conductor ( 3 ) of the coaxial line. This disposition makes possible to develop the housing ( 2 ) of the system ( 1 ) concentrically to the longitudinal axis ( 9 ) and the housing ( 2 ) has no projecting elements.

Description

The invention relates to a Störschutzfilter- and Blitzstromableiter device in a coaxial line for transmitting high-frequency signals, comprising a housing with two connectors, wherein the housing forms a ground-connected outer conductor, an inner conductor guided through the housing and a short-circuit connection between inner conductor and housing.

Noise filter and lightning arrester devices of this type are known. They serve assemblies, devices or systems which are connected to lines, e.g. Coaxial cables of telecommunications equipment to protect against electromagnetic pulses, surges and / or lightning currents. Artificial magnetic pulses may be generated, for example, by motors, switches, switched-mode power supplies or even in connection with nuclear events, and pulses of natural origin may arise, for example, as a result of direct or indirect lightning strikes. The known protective circuits are arranged on the input side of the modules, devices or systems, which may be dissipative or reflective systems.

An EMP arrester of this kind is out EP 938 166 known. This EMP arrester has a housing, which serves as an outer conductor and is connected to the ground. In a first part of this housing, which runs in the direction of the insertion axis of a coaxial cable, an inner conductor is guided. In a second housing part, which protrudes at right angles from the first housing part, a λ / 4 short-circuit conductor is arranged, which connects the inner conductor to the housing. With this known T-arrangement can be achieved with suitable, known geometric arrangements and configurations already a very good protection of the connected devices, modules or systems. EMP arresters of this type must comply with international standards and comply, for example, with the test conditions in accordance with the IEC standard. Despite the good in itself effectiveness, arresters of this type have the disadvantage that even a residual pulse and thus a residual energy is delivered via the inner conductor to the connected modules, devices or equipment. A further disadvantage is that the housing part arranged at right angles to the inner conductor, which accommodates the λ / 4 arrester, is relatively large and leads to a bulky construction of this arrester. Often prepares the installation of such arresters due to the projecting λ / 4 component at right angles considerable difficulties, and it must be complied with corresponding distances between adjacent components. This design can not be covered with a shrink tube against environmental influences, but is wrapped in practice with corrosion protection tapes. This causes greater costs.

document FR-A-2 092 319 discloses a device according to the preamble of claim 1.

It is therefore an object of the present invention to provide a Störschutzfilter - and Blitzstromableiter device in which the remaining residual pulses and residual energies are additionally reduced, the housing has no right angles projecting additional components and the whole device should be made compact and largely axially symmetrical.

This object is solved by the features defined in the characterizing part of claim 1. Advantageous developments of the invention will become apparent after the features of the dependent claims.

In the solution or device according to the invention, the longitudinal axis of the inner conductor and the longitudinal axis of the short-circuit connection between the inner conductor and the housing are arranged approximately parallel to one another. At the same time, the longitudinal axes of the inner conductor and the short-circuit connection are approximately parallel to the longitudinal axis of the device or of the housing. All essential Components of the device are arranged around the longitudinal axis of the housing, that the housing may be formed concentrically to the longitudinal axis. This arrangement results in a compact cylindrical configuration of the device in which the input and output for the cable, or the corresponding connector on the same axis and this coincides with the longitudinal axis of the device. The arrangement of two oppositely directed short-circuit lines, which form the short-circuit connection between inner conductor and outer conductor, there are further advantages. If interference impulses, which are caused by a lightning strike or another electromagnetic event, are dissipated to ground via the two mutually opposing short-circuit lines, the resulting voltages partially cancel each other out due to the induction effect. This has the consequence that the residual pulses and the residual energies that occur at the output of the device are significantly reduced. Comparative measurements compared to a traditional device with λ / 4 arresters projecting at right angles for the same power range show that in the solution according to the invention the residual voltage pulse can be reduced, for example by a factor of 4 and the residual energy by a factor of 30. These factors can vary within a wide range, depending on the design and choice of materials of the individual components, but in any case, there is a significant reduction in the residual pulse and the residual energy.

Further advantages of the inventive solution result from the fact that the two short-circuit lines do not have the length of normal λ / 4 arresters, but by the inventive arrangement and the configuration of the connection areas between the inner conductor and the two short-circuit lines at the outer ends, the geometric length of the short-circuit lines can be shortened. So-called electrically extended λ / 4 short-circuit cables are formed. In an equivalent circuit diagram, each short-circuit line has a capacitance and an inductance, which operate in parallel. This embodiment results in a broadband range of action of the device, for example, for high-frequency signals in the range of 1.7 - 2.5 GHz. adjustments to other frequency ranges are possible by changing the capacitances and inductances on the inner conductor and the short-circuit lines in a conventional manner in a wide range. By installing an additional high-pass filter in the inner conductor, namely at the connection side to the device part, the already considerably reduced residual energy can be reduced even further. The significant reduction of the residual pulse by the inventive solution makes it possible to dispense with fine protection circuits, as they are necessary in other known solutions.

In addition to the compact and concentric design, the solution according to the invention makes it possible to install additional pulse-discharging elements between the oppositely directed ends of the short-circuit lines and the housing. For example, gas discharge arresters or varistors or diodes can be used as additional impulse-discharging elements, these elements being decoupled in the working frequency range of the device. This arrangement allows the transmission of supply voltages. The device can thus also be used for the RF decoupling of corresponding additional pulse-diverting elements without the intermodulation behavior being impaired.

Fig. 1

einen Längsschnitt durch eine erfindungsgemässe Einrichtung,

Fig. 2

einen Querschnitt entlang der Linie I-I in Fig. 1,

Fig. 3

einen Querschnitt entlang der Linie II-II in Fig. 1

Fig. 4

ein Ersatzschaltbild für die Einrichtung gemäss Fig. 1

Fig. 5

ein Ersatzschaltbild für eine Einrichtung gemäss Fig. 1 mit einem zusätzlichen Hochpassfilter, und

Fig. 6

ein Ersatzschaltbild für eine Einrichtung gemäss Fig. 1 mit einem zusätzlichen Hochpassfilter und einem zusätzlichen Ableitelement und einer DC-Einspeisung.

In the following the invention will be explained in more detail by means of embodiments with reference to the accompanying drawings. Show it:

Fig. 1

a longitudinal section through an inventive device,

Fig. 2

a cross section along the line II in Fig. 1,

Fig. 3

a cross section along the line II-II in Fig. 1st

Fig. 4

an equivalent circuit diagram for the device according to FIG. 1

Fig. 5

an equivalent circuit diagram for a device according to FIG. 1 with an additional high-pass filter, and

Fig. 6

an equivalent circuit diagram for a device according to FIG. 1 with an additional high-pass filter and an additional dissipation element and a DC feed.

Fig. 1 shows a longitudinal section through an inventive Störschutzfilter- and Blitzstromableiter device 1 with double-sided connectors 7, 8 for coaxial cable. The coaxial cable is not shown and serves, for example, as a connection between an antenna and a transceiver with corresponding devices. The connectors 7, 8 are known per se, partially standardized components and have both on the input side 19 as on the output side 18 connecting elements, on the one hand the inner conductor of the cable via elements 21 to the inner conductor 3 of the device 1 and on the other hand, the outer conductor of the cable connect to the housing 2 via a mechanical connection 22. In this case, the housing 2 forms the outer conductor 4 of the device 1. The connecting elements 21 are both arranged on the longitudinal axis 9 of the device 1, or of the housing 2, and are supported in the housing 2 via insulator disks 23. An inner part 24 of the connecting elements 21 is electrically conductive, for example by screwing, soldering or crimping, each with a disk 25, 26 is connected. These disks 25, 26 are formed of an electrically conductive material, in particular metal, for example made of brass. These two discs 25, 26 are arranged in the direction of the longitudinal axis 9 of the housing 2 at a distance from each other and form connection points 12, 13 between the inner conductor 3 and two short-circuit conductors 5, 6. The inner conductor 3 is parallel to the longitudinal axis 9 of the housing 2 and at a distance arranged to this. In the illustrated example, the entire inner conductor of the device 1 consists of the connecting elements 21, parts of the disks 25 and 26, and the inner conductor 3. The inner conductor has different geometrical deviations over its length, whereby different reactances, or inductances and capacitances are formed. The two short-circuit conductors 5, 6 are also arranged approximately parallel to the longitudinal axis 9 of the housing 2 and at a distance therefrom. The outer ends 10, 11 of these two short-circuit conductors 5, 6 are connected via the discs 25, 26 with the inner conductor 3 and with connecting elements 21. The inner ends 14, 15 of the two short-circuit conductors 5, 6 are directed against each other and electrically connected via a contact part 16 to the housing 2. In the example shown, the two short-circuit conductors 5 and 6 and the contact part 16 are integrally formed. The two short-circuit conductors 5, 6 and the associated Parts of the disks 25, 26 form the short-circuit connection between the inner conductor 3 and the housing 2. In known manner, by adjusting the geometric dimensions of these elements and the choice of the dielectric 20, the frequency range and the bandwidth can be determined to the desired application range of the device. To improve the electrical property, the inner conductor 3 and the short-circuit conductors 5, 6 are at least partially surrounded by an insulating body 27. In some areas, air is present between the housing 2 and the inner conductor 3 or the short-circuit conductors 5, 6 and the disks 25, 26 as a dielectric. The housing 2 is provided with a flange 28 and a screw 29, for example, to insert and fix it by a passage in an electrically conductive device wall. The derivation of the pulses then takes place via this electrically conductive device wall against the equipotential bonding.

In Fig. 2 is a cross section through the device 1 along the line I-I in Fig. 1 is shown. In this case, the disc 26 can be seen, in which centrally the inner part 24 of the connecting element 21 is inserted and connected thereto. Displaced outwards, the outer end 11 of the short-circuit conductor 6 and the region 13 of the inner conductor 3 are likewise connected to the disk 26. The disc 26 is concentrically surrounded by the housing 2 and between the disc 26 and the housing 2 is the dielectric 20, in this area air.

3 shows a further cross section through the device 1, specifically along the line II-II in FIG. 1. In this case, the inner conductor 3 and the short-circuit conductor 6 can be seen which run approximately parallel to one another and parallel to the longitudinal axis 9. Both the inner conductor 3 and the short-circuit conductors 5, 6 are embedded in the dielectric 20, which is formed in this area by the insulating body 27 and consists for example of the material Teflon.

The inventive Störschutzfilter- and Blitzstromableiter device, as shown and described as an example in Figs. 1-3, has compact and minimal construction dimensions. It allows a large packing density the cables, and there are no protruding components necessary. The housing 2 and thus the whole device 1 can be cylindrical and can thus be used in round holes, and it must be observed no positional orientation. Adjacent cable entries can be arranged close to each other, without interfering with each other elements of the individual devices 1 or that damage occurs. This design can be protected in a simple manner with a shrink tube against environmental influences. At the same time, the device 1 according to the invention has substantially reduced residual pulses and residual energies. If the Störschutzfilter- and Blitzstromableiter device 1 shown as an example subjected to a standardized surge current with a waveform 8/20 microseconds, so for example, a residual voltage pulse of about 16 V and about 13 μJ remains at 25 kA. When a conventional device having a right angle λ / 4 short-circuit conductor for the same frequency band is subjected to the same test, this conventional device has a residual voltage pulse of 70 V and about 430 μJ at 25 kA. At the same time, the device 1 according to the invention and shown as an example is designed in a broadband manner for a frequency range from 1.7 to 2.5 GHz. This broadband design can be used in the entire range of use of approximately 400 MHz up to the upper limit frequency of the connector. The outer diameter of the housing 2 of the illustrated example is 29 mm with these connectors and the total length of the device 1 about these connecting elements 21 approximately 72 mm. Depending on the application and the connectors, or the high frequency range to be transmitted, the dimensions change accordingly.

FIG. 4 shows an equivalent circuit diagram of the high-frequency technical device 1 according to FIG. 1. The inner conductor 3 and the outer conductor 4 extend between the input side 19 and the output side 18. The input or output side 19, 18 is defined according to the direction of the pulse That is, the input side 19 is directed, for example against the antenna and the output side 18 against the device to be protected. The main path formed by the inner conductor 3 comprises a capacitance 30, an inductance 32, a capacitance 34, a Inductor 33 and another capacitor 31. These have different reactance values. The short-circuit conductors 5, 6 are each shown in the equivalent circuit diagram by an inductor 35 and a capacitor 36 connected in parallel. The outer conductor 4, or the housing 2 is grounded.

In Fig. 5 the same equivalent circuit diagram as shown in Fig. 4, but in addition to the output 18 of the main line, and the inner conductor 3, a capacitor 37 is formed. This capacitance 37 forms a high-pass filter in a manner known per se and serves to further reduce the residual energies.

FIG. 6 shows an equivalent circuit diagram for a device 1 according to the invention, in which a direct current feed 38 is provided. In addition to the replacement elements described with reference to FIGS. 4 and 5, this arrangement has an additional impulse-discharging element 39 and a further capacitance 40. As an additional pulse-discharging element 39, a gas discharge arrester, a varistor or a diode can be used. This dissipating element 39 is turned on between the output side 14, 15 of the short-circuit conductors 5 and 6 and the outer conductor 4, or the housing 2. In this case, this additional arrester device 39 is decoupled in the transmittable frequency range.

The discrete equivalent components shown in the equivalent circuit diagrams in FIGS. 4 to 6 can actually be present or are realized by different line lengths and impedances, as shown in the example according to FIG.

Claims (11)

1. Interference filter and lightning current arrester device (1) in a coaxial line for transmitting high frequency signals, comprising a housing (2) with two connectors (7, 8), the housing (2) forming an external conductor (4) which is connected to earth, an internal conductor (3) which is run through the housing (2), and a short-circuit connection (5, 6) between internal conductor (3) and housing (2), the short-circuit connection consisting of two short-circuit lines (5, 6), characterized in that the short-circuit lines are arranged approximately parallel to the internal conductor (3), one end (10, 11) of each of these two short-circuit lines (5, 6) being connected to the internal conductor (3) at two regions (12, 13) which are arranged at a distance from each other, and the two other ends (14, 15) of the two short-circuit lines (5, 6) being directed against each other and connected to the housing (2) via connecting elements (16, 17).
2. Interference filter and lightning current arrester device according to Claim 1, characterized in that each short-circuit line (5, 6) includes a capacitor (36) and an inductor (35), which form a parallel resonant circuit.
3. Interference filter and lightning current arrester device according to Claim 1 or 2, characterized in that in the region of the two connection points (12, 13), between the internal conductor (3) and the short-circuit conductors (5, 6), in each case a capacitor (30, 31) is formed on the internal conductor (3), and the internal conductor (3), between the two connection points (12, 13), has another capacitor (34) and at least one inductor (32, 33).
4. Interference filter and lightning current arrester device according to one of Claims 1 to 3, characterized in that on the output side (18), on the internal conductor (3), a high pass filter (37) is arranged.
5. Interference filter and lightning current arrester device according to one of Claims 1 to 4, characterized in that between the ends (14, 15), which are directed against each other, of the short-circuit lines (5, 6) and the housing (2), a capacitor (40) and parallel to it an additional pulse-diverting element (39) are arranged.
6. Interference filter and lightning current arrester device according to one of Claims 1 to 5, characterized in that between the internal conductor (3) on the one hand and the short-circuit conductors (5, 6) and housing (2) on the other hand, a dielectric (20) is arranged.
7. Interference filter and lightning current arrester device according to one of Claims 1 to 6, characterized in that with the exception of the connecting elements (16, 17) between the short-circuit conductors (5, 6) and the housing (2), all effective components are arranged concentrically to the longitudinal axis (9) of the device (1) or parallel to the longitudinal axis (9) of the device (1).
8. Interference filter and lightning current arrester device according to one of Claims 1 to 7, characterized in that the short-circuit lines (5, 6) are electrically extended λ/4 short-circuit lines.
9. Interference filter and lightning current arrester device according to one of Claims 1 to 8, characterized in that the different line sections of the short-circuit conductors (5, 6) and connecting elements (25, 26) determine the bandwidth and frequency range of the HF transmission.
10. Interference filter and lightning current arrester device according to one of Claims 1 to 9, characterized in that the different line sections of the internal conductor (3) and the dielectric (20) determine the characteristic over the bandwidth of the HF transmission.
11. Interference filter and lightning current arrester device according to Claim 5, characterized in that the pulse-diverting element (39) is a gas discharge arrester or a varistor or a diode, and over this pulse-diverting element (39) and the capacitor (40) a direct current feed is arranged.

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