DE20122683U1 - Data communication apparatus through power distribution lines/cables, has primary winding which couples data signal through conductor of power transmission cable - Google Patents

Abstract

A primary winding couples a data signal through a conductor of power transmission cable. A secondary winding inductively coupled to the primary winding, couples the data signal through a data port. Independent claims are also included for the following: (a) A data communication network implemented over a power distribution system; (b) A neutral wire identification method of power transmission cable; (c) A neutral wire identification system.

Description

The The present invention relates to the communication of a data signal via a Energy distribution system and in particular the use of an inductive Coupler for coupling a data signal via a conductor in a power transmission cable.

On a household or a company limited low-voltage (LV) lines are as volumes for point-to-point or network communications using so-called "bearer" systems in which a data signal is modulated onto a radio frequency (RF) carrier and over transmit the power lines becomes. An Internet access that has a "last-mile" connectivity between the Internet data base and every household would require the usefulness greatly increase such networks.

A Medium voltage (MS), usually 4-66 kV, will over a MS-NS distribution transformer to a low voltage (NS) usually 100-500 volts reduced. A medium-voltage power distribution network supplied many households and companies over Distribution transformers. If data is available in the medium-voltage network are, would be it desirable Broadband pipes from substations to entire legs of a residential area but the distribution transformers effectively block high frequency energy and thus prevent the data from entering the NS downpipes.

In countries use the nominal low voltages of 125 volts or less, As in North America, downcomers are from the distribution transformer usually kept shorter than about 50 meters for electrical load in the home or office, so that the voltage drop along the lines decreases and a adequate voltage regulation is maintained. Usually will from each distribution transformer only one to ten households or Companies supplied. For such a small number of possible It is not economical for consumers, an expensive feed with high data transmission rate, such as fiber or T1, and provide them via power line communication devices to couple to the low voltage side of the transformer. To that Medium voltage power distribution network as data return (backhaul) Thus, a device is required with the the distribution transformer can be bridged.

at A power distribution system becomes a high voltage (HS), usually 100-800 kV from a HS-MS step-down transformer transformed down to a medium voltage in a substation. The high frequency blocking features of distribution transformers isolate the medium-voltage power distribution network high-frequency noise affecting both the low-voltage and also the high voltage (HS) lines is present. The medium voltage network is therefore a relatively noise-free Carrier, the for the high-speed data communication as a data distribution system or "backhaul pipe" is ideal.

The mentioned above Transformers block almost every megahertz frequency range. To couple high frequency modulated data from the MS lines to the NS lines, Must have a lock-up device be installed at each transformer station. At the moment there are devices available and will be for Low-frequency, low-data-rate data link applications used. Such applications are often called Power Line Communications (PLC). These devices usually include one High voltage series coupling capacitor, the one Basic Impulse Loading- (BIL-) Voltage, usually over 50 kV, must withstand.

Such Devices are very expensive and bulky and have an impact on the entire reliability of the power supply network. Besides, they require in some make while their installation, the energy shutdown at the customer.

In countries with a nominal low voltage in the range of 100-120 volts, like Japan and the US, is the number of distribution transformers especially high. The reason for this is that the MS-NS distribution transformers are relatively close be placed on the load to low the feed resistance to keep. A low feed resistance is desirable by an adequate degree of voltage regulation, i. minimum Fluctuations in the supply voltage at different load currents, maintain. NS supply lines for distances of much more than 50 meters would impracticable require thick cables.

For a data coupler to be effective, it must be considered in the context where it operates in conjunction with the high frequency characteristics of the MS power lines and other components connected to those lines, such as transformers, power factor correction capacitors, PLC coupling capacitors, and circuit breakers. These components work in different countries and regions at different voltages. The level of operating voltage has a direct impact on the design geometry of medium voltage power devices as well as on the clamp impedance of these devices at megahertz frequencies. Other factors that affect radio frequency signals in MS power lines include network geometry, such as branching, the use of very low impedance underground cables connected to high impedance catenaries, and the ability to split a network into subnetworks by operation a circuit breaker. Therefore, the suitability of an MS-NS coupling device must be considered in the context of the specific characteristics of the equipment used in each country and the MS voltage level.

Overground transmission lines are characterized by two or more cables that are in essence constant distance with air dielectric in between. Such Lines have a characteristic impedance in the range of 300 up to 500 ohms and very low losses. Coaxial underground cable include a center conductor surrounded by a dielectric is over the center conductor are wound. Such cables have a characteristic Impedance in the range of 20 to 40 ohms and show losses for megahertz signals, depending on the loss characteristics of the dielectric only 2 dB per hundred meters in length can be.

One MS-NS distribution transformer, whether he is now for the operation of one-phase to center conductor or from phase to phase in a three-phase network has a primary side winding on the MS side, those with an impedance in the range of 40 to 300 ohms for frequencies above 10 MHz occurs.

Power factor correction capacitors have high nominal capacity values (e.g., 0.05-1 μF), but their high-frequency impedance is determined primarily by series inductance, which is based on their design is. PLC coupling capacitors have lower nominal capacitances, for example Example 2.2-10 nf, can but have high frequency impedances that are proportional to the characteristic impedance of the power cable are relatively low. Each of the above mentioned Devices can produce a resonance in the megahertz range, i. the imaginary Part of a complex impedance will be zero ohms that have devices however, no high Q factors at these frequencies, and so is approaching the order of magnitude the impedance is usually not zero for a series resonance or an extremely high value for a parallel resonance.

A other device, especially in Japan on MS power supply networks used is a remote-controlled three-phase disconnector. When a data signal over transmit a phase line will, which runs through such a switch, must ensure the continuity of the data be maintained, even if the phase line through the switch open becomes.

It It is an object of the present invention to provide an improved Coupler for coupling a data signal to a conductor in one Power transmission cables provide.

It is another object of the present invention, such To provide coupler, which is inexpensive and a high data transmission speed has.

It is another object of the present invention, such Provide coupler without interrupting the supply to Energy consumers can be installed.

It is still another object of the present invention, a provide such coupler, the only passive components used, which have a virtually unlimited life.

These and further objects of the present invention are achieved by a Device for enabling the communication of a data signal via a power transmission cable achieved, comprising (a) a first winding for coupling the data signal via a Head of power transmission cable and (b) a second winding that is inductive to the first winding coupled to couple the data signal via a data input.

1 Fig. 10 is an illustration of a conventional underground medium voltage distribution coaxial cable showing a neutral conductor used as a communication medium according to the present invention.

2A is an illustration of an inventive arrangement of a single-ended transmission line, which uses a single neutral conductor for data communication.

2 B is a schematic representation of the arrangement of 2A ,

3A Figure 11 is an illustration of a power transmission cable in which two neutral conductors are used as the transmission line according to the invention for the communication of a data signal.

3B is a schematic representation of in 3A shown arrangement.

3C is a schematic representation of a r alternative to the in 3A shown arrangement that uses a plurality of neutral conductors to form a data transmission line.

3D is an illustration of a technique for realizing the in 3C shown arrangement.

4A and 4B illustrate embodiments of a magnetic core topology for a coupler for use with a pair of neutral conductors that are differentially operated with a data signal.

5A Fig. 10 is an illustration of an arrangement of a high-impedance cable inserted by arranging a magnetic loop core.

5B is a schematic representation of the arrangement of 5A ,

6A - 6C Figures 12 and 12 are diagrams of several symmetrical transmission line arrangements according to the invention using two neutral conductors and magnetic induction.

6D is a schematic representation of the arrangements of 6A - 6C ,

7 is a schematic representation of a symmetrical transmission line according to the invention, which uses a magnetic induction.

8th Figure 4 is a schematic representation of an embodiment of the present invention utilizing multiple transmission lines with multiple sets of neutral conductors.

9A is a schematic representation of a system for identifying a line of a plurality of lines of a power transmission cable.

9B FIG. 4 is an illustration of a system for identifying a line from a plurality of lines of a power transmission cable. FIG.

10A and 10B Fig. 2 are schematic illustrations of portions of a data communication network according to the invention employing a power distribution system, the data being transmitted on a phase conductor of the power distribution system.

11A is an illustration of an embodiment of an inductive coupler according to the invention for coupling data via a phase conductor.

11B is a schematic representation of in 11A shown embodiment.

12 Fig. 12 is a schematic representation of a portion of a network having inter-coupling modems on an inductive coupler.

13 is a schematic representation of a technique according to the invention for the passive coupling of modulated data between sections of a power grid.

14 Figure 4 is a schematic representation of a technique for coupling modulated data between portions of a power grid using inter-coupling modems.

15 Figure 4 is a schematic diagram showing several techniques of the invention for coupling data to a phase conductor of a power distribution system in a data communication network implementation.

16A is a schematic representation of a capacitive coupler according to the invention as a conclusion of an unused end of a transmission line.

16B is a schematic representation of a capacitive coupler according to the invention for connecting a modem to an unused end of a transmission line.

16C is a schematic representation of an inventive arrangement of a capacitive coupler for maintaining the continuity of a data signal via a power disconnect switch.

upper and underground medium voltage transmission lines may be used for bidirectional transmission digital data. Cover such transmission lines the way between the substation of a generator and a or multiple MS-NS distribution transformers within a residential area are arranged. Transform the MS-NS distribution transformers down the medium voltage power to low voltage, which then into households and companies.

The The present invention relates to the use of a coupler in a medium voltage power grid. The coupler serves to enable of communication of a data signal via a power transmission cable. He has a first winding for coupling the data signal via a Head of the power transmission cable and a second winding, the is inductively coupled to the first winding, for coupling the Data signal over a data input.

An embodiment of the present invention is provided with a power transmission cable used, which has one or more neutral conductors, ie conductors which are wound around an outer layer of the cable similar to a coaxial cable. One or more of the neutral conductors of the power transmission cable serve as conductors for one or more data signals.

A other embodiment is used with a phase conductor of a power transmission cable. In this case, the phase conductor of the power transmission cable is used as head of one or more data signals.

1 Figure 3 is an illustration of a standard underground medium voltage distribution coaxial cable 100 with an inductive coupler according to the invention coupled thereto. The cable 100 has a plurality of N center conductors 105 spiraling around a core insulator 120 are wound, the one phase line wire 115 surrounds. For example, a Pirelli cable X-0802/4202/0692 TRXLPE 25 KV 260 mil 1/0 A WG A1 cable, available from Pirelli Cavi e Sistemi SpA, Viale Sarca, 222, Milan, Italy 20126, is available a phase conductor wire surrounded by insulation, wrapped around the 8 strands of copper with a diameter of 2.8 mm. Cables with 12 to 16 center conductors are also common.

The middle conductors 105 are separated in a cable section and isolated from each other. At one end of the cable 100 is a strand of each middle conductor 105 wound open and tangential, leaving a ring of copper wire 125 is formed at a short distance from the cable end, which forms a close. These strands come together in a single-stranded ladder 130 and connected to a grounding point on the MS-NS distribution transformer.

A coupler 140 is already from the phase conductor 115 The latter is guaranteed to withstand both the steady state and transient voltages for which the cable is designed. By using existing insulation, it does not need to be re-provisioned for the coupler. The coupler can be packed with ordinary plastic materials.

The coupler 140 comprises a first winding (in 1 not shown) and a second winding (in 1 Not shown). The first winding is provided by the cable itself, while the second winding may comprise one or two turns of a small cross-section stranded wire with minimal insulation.

For a submarine cable, such as the cable 100 , is the use of the inductive coupler 140 particularly cost-effective, as it uses the existing insulator 120 to provide isolation from the medium voltage lines.

One inventive inductive Coupler is also suitable for use with an above-ground Power transmission cable. The inductive coupler is generally less expensive than a capacitive one Coupler, as the layer increase of the isolation of the inductive coupler the performance of the Kopplers essentially not diminished while the increase in insulation thickness in the capacitor its capacity per unit area directly degrades and requires a larger plate area. Therefore, compared to a capacitive coupler, the inductive Coupler much cheaper getting produced.

It There are several alternative embodiments the invention. For Underground cable allows one or more neutral conductors of the underground cable in Claim to form the high-frequency transmission lines can, while maintain the power line function of the selected center conductor (s) remains.

2A is an illustration of an inventive arrangement of a single-ended transmission line, which uses a single neutral conductor for data communication. 2 B is a schematic representation of the arrangement of 2A , A cable 200 includes a variety of center conductors 205 , eg, conductors, which may be considered as a flat data transmission line, in a slight spiral around a high voltage insulator 240 and a middle phase conductor 245 are wound.

A selected strand from the middle ladder 205 ie the center conductor 202 , is isolated so that it can act as the head of a data transmission line for a data signal, and the remaining center conductors 205 , mainly two center conductors 205 leading to the center conductor 202 adjacent serve as a second conductor for a data transmission line. For the cross section of the Pirelli cable described above, the characteristic impedance with respect to signals in a frequency range of 1-50 MHz, of which a subrange is generally used in a data transmission, is estimated to be about 95 ohms. To the arrangement of 2A to realize in an already installed underground cable, the center conductor 202 from the several middle conductors 205 selected and at an open section 210 on each end of the cable 200 cut. A vein 215 the middle conductor 202 stays with a ring 250 on each end of the cable 200 connected. The center conductor 202 and the vein 215 be with a first winding 225 a coupler 220 connected. The first winding 225 is therefore between the middle conductor 202 and the earth connected in series. A second winding 235 the Kopp toddlers 220 gets to an entrance 255 coupled through which data is transmitted and received. Consequently, the cable becomes 200 for use as a radio frequency transmission line connected to communication equipment such as a modem (not shown) via the coupler 220 can be connected.

Electrotechnically expressed, is the coupler 220 a transformer. The impedance along the primary-side, ie first, winding 225 such a transformer is negligible at the frequencies used for the power line. The first winding 225 that with the center conductor 202 and the vein 215 should be wound with a wire that is at least as thick as the center conductor 202 , Under these circumstances, the selected data-carrying center conductor has 202 essentially the same impedance as all other center conductors. It transmits substantially the same current as any of the other center conductors, and the total allowable amperage and surge current capacity of the zero circuit is not attenuated.

In the 2A and 2 B the neutral current of the single center conductor flows 202 through the coupler 220 , For a 200-amp cable with eight neutral conductors, the data-carrying conductor then transmits a maximum steady state current of 25 amps rms. The maximum steady state current through a single center conductor is smaller for a lower allowable power cable and for a cable with a larger number of center conductors. The coupler 220 must be able to cope with the flux generated by this current without magnetic saturation, so that it can perform its data coupling function.

The center conductor 202 transmits power for a high frequency data signal in a first direction. The other middle conductors 205 Transmit the reverse current of the data signal in the opposite direction, and they tend to cancel an intensity of the radiated magnetic field due to the modulated data signal and thus greatly attenuate. This arrangement also provides an electrostatic shielding effect against noise coupling from an external electric field.

3A is an illustration of a power transmission cable according to the invention 300 in that two neutral conductors are used as a transmission line for communication of a data signal. 3B is a schematic representation of in 3A shown arrangement.

A coupler 307 , for example, a high-frequency transformer, comes with two adjacent neutral conductors 302 . 305 connected in series. The neutral conductors 302 . 305 which are preferably parallel and adjacent to each other are cut short before a point where they connect with the neutral connecting ring 330 meet.

Please refer 3B : The wires of the neutral conductors 302 . 305 that are different from the cable 300 extend are to a first winding 310 of the coupler 307 connected. The first winding 310 is thus between the center conductor 302 and the center conductor 305 connected in series. The first winding 310 includes a center tap 312 and a magnetic core 315 , The center tap 312 is to the neutral connecting ring 330 connected.

An area 310A the first winding 310 is to the neutral conductor 302 connected and in a first direction around the core 315 wrapped, and a second area 310B the first winding 310 is to the neutral conductor 305 connected and in the opposite direction around the core 315 wound. The areas 310A and 310B are made from wires of slightly larger diameter than the neutral wires of the power cable and are therefore able to support steady state and surge currents at least as well as the unselected center conductors. Each of the areas 310A and 310B can itself be considered as a winding.

The arrangement of 3A ensures that in line with the two center conductors 302 . 305 only a negligible impedance is introduced, which does not interfere with the substantially equal division of the line frequency current among all center conductors. For the Pirelli cable described above, the characteristic impedance of the parallel conductors 302 and 305 which act as a parallel conductor transmission line is estimated to be about 130 ohms. At mains frequency, the in 3A and 3B Furthermore, the arrangement shown to cancel the flow due to the neutral current in the windings 310A and 310B flows in opposite directions, resulting in a negligible net flow through the core 315 leads.

Another winding 320 is at an entrance 350 connected through which data is transmitted and received. The winding 320 is from the power circuit center conductor 325 is isolated so as to avoid a ground loop that could cause noise and surge currents in the data loops.

The cable 300 may be considered as a radio frequency transmission line connected to the communication equipment via the coupler 307 can be connected. In this configuration, a data signal passes through the center conductors 302 . 305 guided differently. Such a transfer transmission line should emit even lower electromagnetic radiation for a given operating power level than that in 2A described one-sided grounded arrangement.

3C is a schematic representation of an alternative to the in 3A and 3B shown arrangement that uses a plurality of center conductors to form a data transmission line. The cable 300 has a plurality of middle conductors 330 which are substantially parallel to each other, with individuals from a first subgroup 330A the majority of middle conductors 330 with individuals from a second subgroup 330B the majority of middle conductors 330 alternate. The first subgroup 330A is considered overall as a first center conductor and connected together to form a first stranded wire 332 to a coupler 307A to build. The second subgroup 330B is considered overall as a second center conductor and connected together to form a second stranded wire 333 to a coupler 307A to build.

Preferably, the plurality of neutral conductors 330 configured as N / 2 transmission lines connected in parallel, where N is the number of neutral conductors 330 and N / 2 is the number of neutral conductors in each subgroup 330A and 330B is. Such a parallel connection has the effect of being through the cable 300 reduced attenuation by a factor of about N / 2 and the characteristic impedance is lowered by the same factor.

3D is a diagram that shows how the arrangement of the 3C can be easily realized. To the connection of the first subgroup 330A to the first stranded wire 332 To simplify, becomes a first insulation ring 335 over all middle conductors, ie the first subgroup 330A and the second subgroup 330B , located near a point where the coupler is located 307A will be located. The first subgroup 330A is over the first insulation ring 335 wrapped and joined together to the first stranded wire 332 to build. Likewise, the second subgroup 330B over a second ring 345 wound, which may be insulating or non-insulating, and connected together to the second stranded wire 333 to build. The improved geometric symmetry of the current flow and the lower voltage levels should reduce the electromagnetic radiation compared to the radiation associated with the two-wire implementation of the 3A is sent out, further reduce.

A power company may have objections to cutting two neutral conductors and reconnecting them via a coupler. According to the invention, it is possible to "wind" a magnetic core around the two selected neutral conductors in a manner that is topologically and magnetically equivalent to the one in FIG 3A and 3B shown embodiment.

4A and 4B illustrate embodiments of a magnetic core topology for a coupler for use with a pair of center conductors that are differentially operated with a data signal. Such a core has a first area near a first center conductor and a second area near a second center conductor. The coupler includes a winding wound around a portion of the core. Via the core, the winding induces a first current in the first center conductor in a first direction and a second current in the second center conductor in a second direction opposite to the first direction.

Please refer 4A : A core 400 can be thought of as a figure "8" without contact at the crossover point. The figure "8" forms a topological "twist". A first area includes a first loop 405 the figure "8". A first center conductor 410 gets through the first loop 405 guided. A second area includes a second loop 415 the figure "8". A second center conductor 420 gets through the second loop 415 guided. The core 400 is sort of a continuous single-window core through which the ladder 410 and 420 be guided in opposite directions, so that the flow is canceled due to mains frequency currents. A winding 425 generates high frequency signal currents with opposite phase in the neutral conductors 410 and 420 ,

The topology of Figure "8" can be implemented on the surface of a cable without cutting the center conductors. As in 4B shown, becomes a core, which is the core areas 400A and 400B includes, with a first gap 430 in the first loop 405 and a second gap 435 in the second loop 415 configured. The center conductor 410 gets through the first gap 430 led, and the center conductor 420 is through the second gap 435 guided. By arranging the cores 400A and 400B against the insulation 440 the middle conductor 410 and 420 become the middle conductors 410 and 420 arranged in the path of the magnetic flux.

One Another method for avoiding the physical separation of Neutral is a high impedance for high frequencies to line up with them without cutting the ladder. The present invention accomplishes this by surrounding the entire Cable with one or more magnet coil cores.

5A Fig. 10 is an illustration of an arrangement of a cable with a high-frequency high-impedance danz, which is introduced by arranging a magnet coil core over the cable. 5B is a schematic representation of the arrangement of 5A ,

One or more magnet coil cores 502 become around an area of a power transmission cable 500 arranged. A first winding 530 ( 5B ) of a coupler 515 is between a first center conductor 510 and a second center conductor 512 in relation to the magnet coil cores 502 inward of the cable 500 connected. A second winding 532 of the coupler 515 provides a data path to a modem input 520 ready.

The first and the second center conductor 510 . 512 are two of a plurality of center conductors 505 inside the cable 500 , Every middle conductor 505 is a sort of throttle 502A ( 5B ) just before a neutral collection ring 525 across from. As a result, the solenoid cores switch 502 an insulating reactance, preferably of the order of a few micro-Henry, between each of the neutral conductors 505 and earth.

The magnet coil cores 502 may be configured as a split core of two halves with a mechanical packaging provided such that the core halves are accurately mated and the core on the cable 500 is attached. The advantage of this embodiment is that none of the neutral conductors 505 during the installation of the magnet coil cores 502 must be severed.

A data signal may be from a modem (not shown) that has an input 520 of the coupler 515 connected and to the center conductor 510 . 512 upstream of the magnet coil cores 502 is coupled, transmitted or received by it. As a cable 500 you can get a high frequency transmission line with the connection endpoints 535 and 540 Imagine that are partially isolated from earth by coils that act as throttles.

At mains frequency, the net current is that through the magnet coil cores 502 flows, essentially zero, because the phase current of a center conductor 517 flowing in one direction, being balanced by the oppositely directed neutral current passing through the plurality of neutral conductors 505 flows, all through the magnet coil cores 502 walk. A core saturation is thus excluded. The power distribution under the neutral conductors 505 remains due to the presence of the magnet coil cores 502 unchanged, because a very low reactance due to the throttling effect of the magnet coil cores 502 is induced, which influence all neutral conductors in the same way.

6A - 6C Figures 12 and 12 are diagrams of several symmetrical transmission line arrangements according to the invention using two neutral conductors and magnetic induction. 6D is a schematic representation of the arrangements of 6A - 6C , Again, the advantage gained is the avoidance of the disconnection or manipulation of the neutral conductors for circuits which may or may not be energized.

Each of the embodiments of the 6A - 6D uses two neutral conductors as transmission line. The signal current is magnetically induced in the regions of the neutral near a grounded collection ring. An open magnetic core (such as an "E" core) is placed near and perpendicular to the two neutral conductors.

As in 6A shown has an open magnetic core 605 a first leg 606 near and perpendicular to a first of the two neutral conductors 602 a cable 600 is arranged, a second leg 607 near and perpendicular to a second of the neutral conductors 602 is arranged, and a third leg, that is, a common leg 610 that is between the first leg 606 and the second leg 607 is arranged. The common thigh 610 has a winding wound around it 608 ,

The winding 608 is around the common thigh 610 wrapped between the two neutral conductors 602 of the cable 600 is arranged. This arrangement induces currents in the individual neutral conductors 602 in opposite directions. A section 615 ( 6B ) the neutral conductor 602 Together in a grounded collection ring 625 ( 6B ), may alternatively be considered as a one-turn coil passing through the gap between the pole faces of the legs 606 and 610 and between the pole faces of the legs 607 and 610 passes. So induces a signal current in the winding 608 a signal current in the two neutral conductors 602 which sends a differential signal down the transmission line passing through these two neutral conductors 602 is formed.

Please refer 6C To reduce the size of the relatively large air gap between the legs in standard core shapes (eg, the "E" core) and increase the coupling coefficient, a pair of magnet coil cores 620 with columns provided 627 used by the neutral conductors 602 be guided. A winding 630 is around a range of each of the magnet coil cores 620 , eg a common leg 632 , wrapped.

The equivalent circuit of the embodiments of 6A - 6C is in 6D shown. The Berei the neutral conductor 602 , in which the flux is induced, act as two windings 635 with opposite phase, which together at the collecting ring 625 are connected. A winding 645 makes an entrance 640 ready for connection to a modem (not shown).

The magnetomotive force (MMF) of the mains frequency is in the common Leg of the core lifted, but occurs completely on each side leg on. However the air gap preserves, which has to be wider than that Diameter of a neutral conductor, these side legs usually before, saturated to become.

The advantage of the embodiments of 6A - 6D is that both the interruption and the physical contact with the neutral conductors 602 be avoided. The distribution of current among the neutral conductors remains substantially unchanged at mains frequency because the very low reactance induced by the choke effect of the core produces negligible reactance across the entire cable section as compared to the total neutral impedance. The cable 600 can be thought of as a high frequency transmission line connected to each port via a coupler to communication equipment.

7 is a schematic representation of a symmetrical transmission line according to the invention, which uses a magnetic induction. This embodiment is similar to that of FIG 6D but instead of a single magnetic core or pair of coils coupling to a pair of neutral conductors, it couples to all neutral conductors arranged in pairs. A cable with an odd number of conductors leaves a conductor unused. To achieve this, each of the embodiments of the 6A - 6D be used, wherein the number of couplers corresponds to the number of neutral pairs and the windings of the coupler are connected together. For minimum radiation, the neutral conductors should alternately have an opposite phase.

Similar to the embodiments of 6A - 6D includes the embodiment of the 7 a coupler with a first winding 720 for coupling a data signal over a first center conductor 702 from a power transmission cable 700 and a second winding 740 that is inductive with the first winding 720 is coupled to couple the data signal via a data input 760 , Usually, the embodiment of the 7 this still and contains a third winding 725 for coupling the data signal over a second center conductor 705 of power transmission cable 700 and a fourth winding 745 that with the third winding 725 inductively coupled to couple the data signal via the data input 760 , The data signal travels on a first path over the first center conductor 702 , the first winding 720 and the second winding 740 and on a second path over the second center conductor 705 , the third winding 725 and the fourth winding 745 , The first path is parallel to the second path.

7 illustrates the use of all pairs of neutral conductors according to the embodiment of FIG 6D , The conductor pairs 702 . 705 . 710 and 715 all work as transmission lines in a similar way as the selected pair 600 of the 6D is. The sections of the neutral conductors that pass through the magnetic flux of the cores act as windings 720 . 725 . 730 and 735 and operate the neutral pairs as transmission lines. The windings 740 . 745 . 750 and 755 may be connected in parallel or in any series or parallel combination as shown, providing a consistent phase adjustment, such that a data signal is applied to a data input 760 is delivered. As a middle phase conductor 715 of the power cable 700 is exposed to an equal and an opposite phase flux from the coupling coils, the phase conductor is affected 715 the signal transmission is not.

Some of the advantages of the embodiment of 7 (a) that the installation of a coupler can be done without selecting a pair of center conductors and therefore, without identifying these conductors at the far end of the section (note that phase inversion is possible here, but would not affect the data flow, because modems can tolerate phase inversion of the entire signal), (b) data transmission is possible even if the cable 700 is damaged in its course and some of the neutral conductors unintentionally have ground faults, (c) better cancellation of external fields and lower radiation, and (d) smaller path losses across the cable section.

8th Figure 4 is a schematic representation of an embodiment of the present invention utilizing multiple transmission lines with multiple sets of neutral conductors. This embodiment utilizes any of the 6A - 6D illustrated embodiments, but instead of a single signal path uses a plurality of neutral transmission lines 802 . 805 . 810 . 815 to provide multiple independent transmission channels. 8th shows four transmission channels.

Similar to the embodiments of the 6A - 6D , includes the execution of the 8th a coupler with a first winding 820 for coupling a data signal via a first coin telleiter 802 a power transmission cable 800 and a second winding 825 that is connected to the first winding 820 is inductively coupled to couple the data signal via a data input 830 , In general, the embodiment of the 8th this and contains a third winding 835 for coupling a second data signal via a second center conductor 805 of power transmission cable 800 and a fourth winding 840 that is inductively connected to the third winding 835 coupled to couple the second data signal to a second data input 845 ,

A such plurality can be used to (a) complete double transmission data on one or more channels, (b) multiple unidirectional ones or bidirectional channels, thereby consequently, the overall bandwidth is increased, (c) a redundant transmission data to minimize errors; (d) the introduction of multi-wire interfaces with separate clock, separate clock pulse and separate data lines and (e) the use of a channel for monitoring commands, error messages or other data useful in network management.

For each of the in 6A - 6D shown embodiments and for in 3 - 8th Improvements include the selection of one or two neutral conductors at one end of a cable, such that the same leads must be identified at the distal end of the cable.

9A is a schematic representation and 9B is an illustration of a system 900 for identifying a line from a plurality of lines of a power transmission cable. The system 900 includes a receiver 902 which measures a signal from a selected neutral of the power transmission cable, and an indicator 905 for the strength of the signal. The signal is sent to a selected conductor 925 to a first point 926 applied on the power transmission cable. The recipient 902 measures the signal at a second point 927 on the power transmission cable away from the first point.

The system 900 also includes a ferrite coil 915 with a radial slot 920 through which the selected neutral conductor 925 is guided, and a winding 930 around a portion of the ferrite coil 915 wrapped and with an entrance 935 Recipient 902 connected is. The signal is from the selected neutral 925 over the ferrite coil 915 inductively coupled. The signal is sent to the selected neutral conductor 925 at the first point 926 via an inductive coupler 924 created.

At the first end of the cable to be connected, the line (s) are selected and a coupler is connected. 9A shows a pair of selected neutral lines. The coupler is driven by a low voltage high frequency oscillator, usually in the MHz range. This results in high frequency current flowing the most in the selected conductor (s).

At the distal end becomes the radio receiver 900 set to the same frequency. This radio receiver is special in that it uses a signal strength meter 905 and a manual or automatic gain control 910 equipped to optimize the gain. In addition, the antenna of the receiver comprises a ferrite coil 915 with a radial slot 920 which is slightly larger than the diameter of the neutral conductor 925 , and one on the ring 915 wound coil that connects to the antenna input terminals of the receiver 935 connected. The ring is preferred 915 firmly mounted on the receiver housing.

The installer holds the receiver so that the slot is in line with and near the center conductor 925 aligned, and observe the reading on the signal strength meter 905 , The installer then moves the receiver tangentially around the cable, measuring each conductor in turn. The conductor (s) that produce the maximum reading on the signal strength meter are those that are directly excited at the other end of the cable.

Therefore includes a method of identifying one of a plurality of neutral conductors of a power transmission cable the steps of (a) applying a signal to a selected signal conductor to a first point on the power transmission cable, (b) measurement a relative signal strength each of the plurality of neutral lines at a second point the power transmission cable that far from the first point, and (c) identifying the chosen Neutral conductor based on the relative strengths. The identification step identifies the selected one Neutral as that of the majority of neutral with the largest relative Strength. The application step involves the inductive coupling of the signal at the selected Neutral, and the measuring step includes the inductive coupling the signal from the selected one Neutral.

So far, the present invention has been described in the context of a cable having a plurality of separate, mutually insulated neutral conductors. However, many power distribution networks do not use cables with neutral conductors isolated from each other, but the neutral conductors are located rather in the form of a net or as several conductors interconnected by conductive copper tape. The 10A . 10B . 11A and 11B and their related disclosures relate to an application of the present invention for other common medium voltage power grids, such as those transmitted on land lines and those transmitted over single neutral neutral pseudo-coaxial underground cables.

One Coupler, which makes physical contact with a medium-voltage phase conductor avoids, is desirable to that effect, that such a coupler the stationary or surge voltages of Phase conductor does not need to withstand, so the construction is simplified and the cost of the coupler can be reduced. however requires the use of the inventively proposed inductive Kopplers precede a circuit continuity, reducing the current flow can, while the medium voltage circuits either physically at their ends open circuits include or connected to transformer windings could be, their high impedance at radio frequencies in about the effect of a May correspond to idle completion. According to the invention, inductive couplers in a medium voltage data backhaul network used when adding high-frequency terminations, where capacitively coupled inputs at the ends of the cable and, in a large distribution network, also at one or more intermediate positions. The phase conductors of underground power transmission lines can be used as Data transmission lines used when equipped with load locks that for coupling data signals to and from the transmission lines are effective at the high frequencies used for communications.

In Power distribution systems is the medium voltage network of devices connected, which show an impedance opposite to signals at high frequencies is much higher than the characteristic one Impedance of the cable. Such devices are against high frequency signals so to speak as open circuits. The coupling of modulated data packets On such an idling cable would cause a large part a coupled wave from the ends of the cable and reflected possibly of data receivers is interpreted as new packets. Another unwanted Feature of such reflections would be that they are the data recipients falsely led to the conclusion that new packages occupy the cable, and Multiple access types of shared networks suffered a loss on available transmission time.

at Cables and conductors with significant high frequency losses disappear These reflections are fast and do not cause any problems. however as well as Overhead lines as well for some pseudo-coaxial underground lines, the losses are low, and strongly reflected signals and the direct signals can become overlay each other.

10A and 10B FIG. 13 are schematic illustrations of portions of a data communications network employing a power distribution system, the data being transmitted via a phase conductor of the power distribution system. The present invention uses a combination of inductive and capacitive couplers. As discussed below, the network comprises (a) an inductive coupler for coupling a data signal across the phase conductor to a data input for further coupling the data signal, and (b) a capacitive coupler connected between the phase conductor and ground proximate one end of the power transmission cable is connected, the reflections of the data signal is absorbed and optionally used as a data input for coupling the data signal.

The inductive couplers 1002 be as intermediate nodes 1005 close to a distribution transformer 1010 used. Each inductive coupler 1002 makes an entrance 1015 ready for connection to a modem (not shown) via a low voltage network from the secondary side of each distribution transformer 1010 is operated. The capacitive couplers 1020 are connected between one end of a conductor or cable and a local ground to absorb both reflections and signal coupling nodes 1025 provide. That is, a signal coupling node 1025 is located between a capacitive coupler 1020 and ground to couple the data signal between the phase conductor and provide another data input for the data signal.

The "wire or cable end" includes a dot 1018 where the energy from a high voltage to medium voltage transformer is fed into the cable. In loop topologies, the cable returns to this position, but reaches an unused end. At these "unused ends" are capacitive couplers 1020 contain. Should be a T branch 1030 a stub line 1035 in the energy network, becomes a capacitive coupler 1020 used to the distal end of the stub 1035 to end.

11A is an illustration of an embodiment of an inductive coupler according to the invention 1102 for coupling data via a phase conductor. 11B is a schematic representation development of in 11A shown embodiment.

An inductive coupler 1102 includes a first winding 1104 for coupling the data signal via a phase conductor 1110 and a second winding 1115 that is connected to the first winding 1104 is inductively coupled to couple the data signal via a data input 1145 , The inductive coupler 1102 includes a core 1105 through the phase conductor 1110 to be led. This configuration of the phase conductor 1110 through the core 1105 serves as the first winding 1104 ie a winding with a single turn. The second winding 1115 is around an area of the core 1105 wound.

The inductive coupler 1102 is a current transformer in which the core 1105 over a section of the phase conductor 1110 is arranged. The inductive coupler 1102 Can also be used with an underground cable by the core 1105 is disposed over a portion of the underground cable, which is not also covered by a neutral conductor sheath, wherein the power cable phase conductor as a winding with a rotation through the core 1105 passes.

The core 1105 It consists of ferrite or other light magnetic material of considerable permeability and relatively low loss over the frequency range required for the modulated data. The core 1105 has an air gap 1120 , which is sufficient for the operation of the inductive coupler 1102 without saturation, even if the current through the phase conductor 1110 as high as the maximum current for which the conductor 1110 is designed, for example, 200 amps rms.

The inductive coupler 1102 has a primary magnetizing inductance sufficient to exhibit a significant high frequency impedance over a relevant frequency range over a modem transmitter but a negligible impedance at power distribution frequencies. The inductive coupler 1102 has both a leakage inductance and a reflected-primary impedance over the relevant frequency range which are substantially less than the characteristic impedance of the transmission line from which the phase conductor 1110 is a component.

The inductive coupler 1102 has a high voltage capacitor 1125 in series with the second winding 1115 and the data input 1145 connected to a low voltage output, ie a power line output, of a distribution transformer 1130 is connected to prevent the second winding 1115 with a low voltage circuit 1135 forms a short circuit. Consequently, the capacitor couples 1125 a data signal between the second winding 1115 and the power line output.

The inductive coupler 1102 also has a surge protection 1140 that with the second winding 1115 connected in parallel to the low voltage circuit 1135 and protect any electronic communications equipment connected thereto from being affected by a high amplitude pulse on the phase conductor 1110 can occur and through the inductive coupler 1102 is coupled to the low voltage lines.

It should be noted that although only one NS phase line 1150 and an NS neutral line 1155 to the coupler 1102 are connected, but the other phase line 1160 a slightly attenuated signal by means of capacitive and inductive coupling over the length of the NS-downpipes receives.

A important consideration and a desirable one The aim is to minimize the electromagnetic radiation from the Cables and cables for the transfer to be used by data. These cables can cause electromagnetic interference even if they bury some feet under the ground are. disturbing Resonances can also the transmission over certain narrow frequency bands prevent.

• (A) Verwendung einer Spreizspektrummodulation in den Modems, die zum und vom Mittelspannungsnetz angeschlossen sind. Die Spreizspektrummodulation verwendet eine verhältnismäßig niedrige Spektralenergiedichte (z.B. –55 dBm/Hz).
• (B) Minimierung des Energieniveaus der modulierten Daten. Das Energieniveau sollte hoch genug sein, um jegliches Rauschen auf der Leitung und jegliches selbsterzeugtes Rauschen der Ausrüstung, z.B. internes Rauschen, Verstärkerrauschen usw., zu überwinden. Durch Ausnutzen der verhältnismäßigen Isolierung der Mittelspannungsleitung von den verrauschten Niederspannungs- und Hochspannungsnetzen kann das Leitungsrauschen minimiert werden. Dies kann durch Anordnung von Wechselkopplungsmodems an jeden induktiven Koppler durchgeführt werden. Wechselkopplungsmodems haben den Zweck, einen Bitstrom zu regenerieren und die Datenübertragung über einen zusätzlichen Träger zu remodulieren.

One or more techniques should be used to minimize radiation, tolerate resonances, and provide a stable and reliable data channel. The choices for minimizing the rays include:

• (A) Use of spread spectrum modulation in the modems connected to and from the medium voltage network. The spread spectrum modulation uses a relatively low spectral energy density (eg, -55 dBm / Hz).
• (B) Minimization of the energy level of the modulated data. The energy level should be high enough to overcome any noise on the line and any self-generated noise in the equipment, such as internal noise, amplifier noise, etc. By exploiting the relative isolation of the medium voltage line from the noisy low voltage and high voltage networks, line noise can be minimized. This can be done by placing inter-coupling modems on each inductive coupler. Interchangeable-pair modems have the purpose of regenerating a bitstream and remodulating the data transfer over an additional carrier.

12 Figure 3 is a schematic representation of a portion of an interchangeable network dems on an inductive coupler. A first modem 1202 has a first entrance 1225 to a data input of a second winding of an inductive coupler 1102 connected to send and receive a modulated data signal, and a second input 1210 for further coupling of the digital data. A second modem 1205 has a first digital data input 1230 which is at the second entrance 1210 of the first modem 1202 connected, and a second input 1235 for further coupling of the modulated data signal. Optionally, a router 1220 between the first modem 1202 and the second modem 1205 be set.

• (A) Das Rauschen des NS-Netzes erreicht das MS-Netz nicht. Die Isolation kann ferner durch optische Isolatoren in Reihe mit der Datenverbindung 1210 verstärkt werden.
• (B) Ein Spreizspektrum- oder ein anderes Modem, das eine andere Technologie oder andere Parameter als das MS-Modem verwendet, kann für NS-Netze optimiert werden. Die induktiven Koppler führen eine zusätzliche Reihenimpedanz an den Kopplungsknoten ein, die verhältnismäßig klein gegenüber der charakteristischen Impedanz des Leiters oder Kabels ist, so dass sowohl die Reflektionen als auch die Energieabsorption minimiert werden. In diesem Fall können die modulierten Daten eine große Anzahl von dazwischenliegenden Knoten erfolgreich durchqueren. Bevorzugt sind die Magnetisierungs- und Streuinduktivitäten klein genug, dass Impedanzstörung minimiert wird, aber groß genug, um eine ausreichende Kopplung bereitzustellen. Vorausgesetzt ist hier eine absichtliche Impedanzfehlangleichung zwischen dem Modem und der Impedanz des Kopplers.
• (C) Router und andere Netzwerkvorrichtungen 1220 können zur Vermittlung zwischen dem Heim- und dem externem Netzwerk eingesetzt werden.

The advantages of the above device are:

• (A) The noise of the LV network does not reach the MS network. Isolation may also be accomplished by optical isolators in series with the data link 1210 be strengthened.
• (B) A spread spectrum or other modem using a different technology or parameters other than the MS modem can be optimized for NS networks. The inductive couplers introduce an additional series impedance to the coupling node that is relatively small relative to the characteristic impedance of the conductor or cable so that both the reflections and the energy absorption are minimized. In this case, the modulated data can successfully traverse a large number of intermediate nodes. Preferably, the magnetizing and leakage inductances are small enough that impedance distortion is minimized, but large enough to provide sufficient coupling. Provided here is a deliberate impedance mismatch between the modem and the impedance of the coupler.
• (C) Routers and other network devices 1220 can be used to mediate between the home and the external network.

One Useful parameter for minimizing the radiation is a weakening of the signal strength in the direction between line and coupler, as the signal strength on the medium voltage power line needs to be large enough to accommodate this attenuation to overcome. The weakening in the direction between coupler and line can be without additional Radiation easily by applying more energy to the coupler, who controls the line, overcome so as to be the maximum allowable transmitted Energy level in accordance with maximum allowable radiation levels.

If for example, every coupler for a coupling loss of 10 dB is designed, then the transmitted Energy for compensation can be increased by 10 dB, and only the 10 dB of the second coupler are deducted from the loss budget of the modem.

13 is a schematic representation of a technique according to the invention for the passive coupling of modulated data between sections of a power grid. 13 shows a data communication network 1300 , which is implemented via an energy distribution system and a first section 1302 with a first center conductor 1320 and a second section 1303 with a second center conductor 1330 having. The network 1300 includes a first coupler 1306 for inductively coupling a data signal over a first center conductor 1320 and with a data input 1335 for the further coupling of the data signal and a second coupler 1307 with a data input 1340 to the data input 1335 of the first inductive coupler 1306 is coupled, for inductive coupling of the data signal via a second center conductor 1330 ,

The first paragraph 1302 includes a first power transmission cable 1315 on a first side of a power distribution transformer 1345 , The second section 1303 includes a second power transmission cable 1325 on a second side of a power distribution transformer 1345 , The power distribution transformer 1345 has an output to the power line 1350 , The network 1300 further includes a capacitor 1310 between the data input 1335 of the first inductive coupler 1306 and the output power line 1350 for coupling the data signal to the output power line 1350 ,

Everyone Transformer-to-Transformer section becomes a separate one Connection in a multiple connection chain. A coupler is on connected to each cable termination, so except for the last one Transformers at an unused end section two couplers per Transformer are required.

The passive stringing of sections is done by connecting the data inputs 1335 and 1340 the two couplers on each side of the transformer reaches each other. A passive connection with the communication devices that respond to the NS performance 1350 are connected by series coupling of the capacitors 1310 , Similar modems are connected both to the feed point of the network, such as the power substation, and to the low voltage outputs on the user's home.

14 Figure 3 is a schematic representation of a technique for coupling modulated data between portions of a power grid using inter-coupling modems. 14 shows a data communication network 1400 , which is implemented via a power distribution system, the first section 1402 with a first center conductor 1420 and a second section 1403 with a second center conductor 1430 has. The network 1400 includes a first coupler 1406 for inductively coupling a data signal over a first center conductor 1420 with a data input 1435 for the further coupling of the data signal and a second coupler 1407 with a data input 1440 to the data input 1435 of the first inductive coupler 1406 is coupled, for inductive coupling of the data signal via a second center conductor 1430 ,

A first modem 1460 includes a first input for modulated data signals 1465 to the data input 1435 of the first coupler 1406 is coupled, and has a second input for digital data 1470 for further coupling of the data signal. A second modem 1480 has a first input for digital data 1475 which is at the second entrance 1470 of the first modem 1460 coupled, and a second input 1485 for the further coupling of the modulated data signal.

The power distribution system includes a power distribution transformer 1445 with an output power line 1450 , The network 1400 also includes capacitors 1410 between the second entrance 1485 of the second modem 1480 and the output power line 1450 for coupling the modulated data signal to the output power line 1450 ,

One Medium voltage cable may include a long cable section, such as from a substation to the first distribution transformer in a loop. To simplify installation and maintenance The long section can be subdivided, with each node using manholes is equipped as access. At these points, the cable sections in Medium voltage connections (for the center conductor) together with neutral conductor collecting rings grounded are, end. This leads to a discontinuity in the data transmission line which is transmitted on one or more neutral conductors. To bridge this discontinuity, can a pair of couplers are installed on each side of the earth, being their primary pages connected to each other and establish a bridge connection.

The present invention also provides implementation of a data communications network, wherein a phase conductor over Sections of an energy distribution system is used.

15 Figure 3 is a schematic diagram illustrating several techniques of the invention for coupling data to a phase conductor of an energy distribution system in a data communication network implementation 1500 shows.

A capacitive coupler is placed on overhead lines fed by a HS-MS step-down transformer. The secondary-side impedance of the transformer is of the same order of magnitude as that of the overhead lines or larger. A terminating coupler, such as a capacitive coupler with a data input, may be used herein which is both (a) used to couple a modem to the line and (b) terminates the line with a resistance approximately equal to that of characteristic impedance of the power transmission cable (as a modem or reactance impedance is reflected by its transformer). Consequently shows 15 in that the power distribution system is an HS-MS step-down transformer 1502 a substation includes. A capacitive coupler 1535 ie a terminator, will be near one. secondary side winding of the step-down transformer 1502 arranged. A component, like the modem 1525 that has an impedance when passing through the capacitive coupler 1535 is approximately equal to a characteristic impedance of the power transmission cable.

In systems such as Japan, where it is common to operate very low impedance underground coaxial cables for lengths of up to hundreds of meters to the beginning of an overhead power grid, the preferred location for inductive couplers is on the above-ground surface of the underground overhead line. transition point. Here, the low impedance of the underground cable acts as a short circuit at the end of the overhead line and a closed current loop is formed. So the power distribution system includes a transition 1545 between a catenary cable 1515 . 1516 and the underground cable 1510 , where the underground cable 1510 has a characteristic impedance that is much lower than that of the above-ground cable 1515 is. One or more inductive couplers 1540 . 1541 be on the trolley cable 1515 . 1516 near the transition 1545 arranged.

The arrangement of inductive couplers 1540 . 1541 on the three-phase overhead line cable 1515 . 1516 can be symmetrical, with each part of a pair of couplers being driven with opposite phase current. Such a drive essentially extinguishes the far-field electromagnetic radiation and simplifies compliance with all regulatory requirements. Accordingly, the network 1500 a pair of inductive couplers 1540 . 1541 such that a first inductive coupler, eg 1540 , the couple's a first stream in phases ladder, eg 1515 generated in a first direction and a second inductive coupler, eg 1541 , the pair a second current in the second phase conductor, eg 1515 generated in a direction opposite to the first current direction.

Alternatively, a single phase may be operated, with equal and opposite currents being generated in the other phases at a distance exceeding one wavelength from an inductive coupler, which in turn extinguishes much of the far field radiation. For example, an inductive coupler 1540 can be used, and after one wavelength down the line, one can rely on the induction effects of the transmission line to balance the currents.

Inductive couplers may also be placed on the lines feeding a distribution transformer on the primary side, since the primary side transformer impedance of some types of distribution transformers may be of the same order of magnitude as that of the overhead lines and a closed loop is formed. Since this loop carries relatively low line frequency currents, usually in the range of 2-8 amps, there is little tendency for core saturation, and the coupler cores can be built with a small or no air gap. As in 15 shown is an inductive coupler 1550 arranged on a line which is a primary-side winding 1555 a distribution transformer of the power distribution system feeds.

As the size of the circuit impedance applied to the inductive coupler 1550 affects up to several hundred ohms and modems 1560 passing along the transmission line to the inductive coupler 1550 connected, typically have an impedance of 50 ohms, there may be a significant impedance mismatch.

As in 15 shown, the power distribution system 1500 a PLC capacitor and / or a power factor correction capacitor, eg the capacitor 1565 , between a phase conductor, eg 1516 , and Earth cover. The capacitor 1565 can have an impedance lower than that of the power transmission cable 1516 is. PLC and power factor capacitors may have high RF impedance, in which case they will not significantly disturb RF signals transmitted over the power grid. For devices with an RF impedance whose size is the same order of magnitude as the characteristic impedance of the power line or lower, such as the capacitor 1565 , can a series thrush 1570 in series with the capacitor 1565 be used. The series thrush 1570 can be an existing conductor wire 1575 to the condenser 1565 include one or more split snap-in magnetic cores over the lead wire 1575 be attached.

Of the Mains frequency current is relatively small, so that nuclear saturation no problem. The micro-Henry size of these inductive impedances of Chokes do not affect the mains frequency function of the capacitor. Lossy cores may as well used, because they increase simply the high frequency impedance of the choke and contribute to the insulation at the condenser.

The Effects of transmission line reflections have to because they produce echoes that contain errors in introduce the data stream can. Spread spectrum modulation is the most likely candidate for one such echoes, because they are opposite Narrow band frequency absorption and narrow band noise is tolerant and emitted electromagnetic radiation due to their low Spectral energy density minimized. In spread spectrum modems affect reflected Signals between packets, the 6-10 dB or more below the direct signal strength are the data reception Not. Reflected signals between packets are defined as reflections, the while the direct receipt of the original package.

Impedance disturbances the power lines can by (a) distribution transformers with or without the addition of inductive coupler impedance, (b) line terminations, usually designed are that they are quite consistent with the line impedance, (c) T-branches and (d) causing PLC or PFC capacitors become. The reflection coefficient of these impedance discontinuities exceeds generally not 0.5, and the reflected signal is subject to and return losses the lines themselves, i. Absorption loss and radiation loss, so that the amplitude of reflected signals is expected by more than 6-10 dB weaker is as direct signals. Consequently, the reflected signals, the while of a data packet, as low-amplitude noise and do not prevent the expected data signals from being received correctly become.

For couplers located at low impedance feed points in high impedance lines, such as the transition 1545 , loss and reflections due to impedance mismatch are not desirable. Since the very heavy power cables can not be wound around the coupler core, on the secondary side, there can be no more than one winding and, on the primary side, not less than one winding will be present. Therefore, the impedance reflected on the power lines is equal to the impedance of the modem, a quarter or less, depending on the turns ratio. For modems with a termination impedance of 50 ohms, this reflected impedance is much smaller than its characteristic impedance. One solution to improve impedance matching is to build modems with an output impedance of a few hundred ohms.

A another solution it is a phase-antiphase pair of couplers with their primary sides connect in parallel. The secondary pages (MS lines) must always be connected in series. So becomes a modem impedance of 50 ohms through the phase-antiphase pair of inductive couplers in a reflected impedance of 100 ohms transformed. This principle can be achieved by using multiple couplers continued whose primary sides are parallel with a series connection of transformer (coupler) Windings on the side of the power line and a parallel Connection on the modem side is reached.

For example, shows 15 a first inductive coupler 1540 and a second inductive coupler 1541 , The first inductive coupler 1540 induces a first current in a first direction in the phase conductor 1515 over a first winding 1540A , and the second inductive coupler 1541 induces a second current in the opposite direction in the phase conductor 1516 over a second winding 1541A , The first winding 1540A and the second winding 1541A are parallel to each other. In 15 are the first winding 1540A and the second winding 1541A marked with dots to show this phase relationship.

Of the inductive coupler at the catenary feed point must be designed this way to be able to withstand the effects of the entire power feed, the can reach several hundred amperes. As well as a coil with a Winding that transmits such a current, the core currently available magnetic Materials for high frequency operation saturates, this "trunk" coupler in general must contain an air gap in its magnetic circuit. In order to achieve a sufficient magnetizing inductance, need such Coupler a plurality of cores; that form the equivalent of a nucleus, which is very thick in the direction of the power cable.

The 16A - 16C 12 are schematic diagrams illustrating multiple uses of capacitive couplers in a communication network implemented via a power distribution system. These capacitive couplers are used at nodes in the network where inductive couplers may not be effective, eg at points where there is an effective open circuit for RF power.

A capacitive coupler 1020 as he is in the 10A and 10B is used in 16A represented and therein as a capacitive coupler 1600 characterized. The capacitive coupler 1600 should be able to handle the operating voltage supplied by the phase conductor and a series of BIL pulses, eg 125 kV at an operating voltage of 15 kV, according to the IEEE specification 386 to be continuously maintained. The capacitive coupler 1600 should also be designed in accordance with the above specification to eliminate corona breakdowns.

The capacitive coupler 1600 is connected to the MS lines via high voltage capacitors 1620 , eg 10 nF, whose impedance at the lowest relevant frequency is a fraction of the characteristic impedance of the power transmission cable. Optionally, the capacitive coupler 1600 a protection fuse 1625 in series with the capacitor 1620 include, so that in case of a short circuit failure of the medium voltage line is prevented.

bleeder resistors 1605 with high resistivity are in parallel with each capacitor 1620 connected so that they discharge them when they are not connected to live circuits. Charged capacitors would be dangerous to the operator. To the data input 1630 further isolating it from the MS lines becomes a high frequency isolation transformer 1615 , optionally with a non-unit winding ratio, if necessary, used for impedance transformation.

To the devices connected to the data input 1630 can be connected to protect a surge protector 1632 , such as a metal oxide varistor (MOV), across the data input terminals 1630 are connected, so that the amplitude of pulses is limited, which could otherwise be coupled from the MS lines to the devices.

Preferably, in the network in which the capacitor is installed, a terminal of the capacitive capacitor 1600 connected to a medium voltage phase line and the other terminal coupled to a neutral (for single phase lines) or to a second phase line (for multiphase lines).

When the capacitive coupler 1600 used to complete an unused end of the transmission line, it can be used together with a terminator 1635 can be used, which is connected to the data input 1630 is connected so that it is matched to the characteristic impedance of the power transmission cable.

16B illustrates the use of the capacitive coupler 1600 for coupling a modem 1636 to an unused end of a power transmission cable. The modem 1636 is at the data input 1630 connected.

16C Figure 3 is a schematic diagram of an arrangement of capacitive couplers to maintain the continuity of a data signal via a power disconnect switch. 16C shows a power distribution system comprising a phase conductor with a first section 1601 on a first page of a switch 1602 and a second section 1603 on a second side of the switch 1602 has. A first capacitive coupler 1650 couples a data signal over the first section 1601 and has a data input 1635 for the further coupling of the data signal. A second capacitive coupler 1660 has a data input 1665 to the data input 1635 of the first capacitive coupler 1650 is connected and the data signal through the second section 1603 coupled. Thus, a transmission of the data signal between the first section 1601 and the second section 1603 Maintained when the switch 1602 is open.

The The present invention employs a variety of network protocols one to expand the physical area and reliability to improve. After passing through inductive couplers and coinciding with impedance mismatches, T-junctions and radiation losses may be the amplitude of that available to the receiver of the modem Signals are very weak. Whether this weakness now on the internal noise a modem or electrical noise of the environment on the medium voltage lines is due there is a physical point below which the signal is not more proven and no longer in data with an acceptable low Error rate can be demodulated.

bidirectional Modems can to be added, to restore and amplify the signal, also using high impedance chokes to isolate the medium-voltage grid into independent sections.

The Data communication network can use communication protocols, the routing of data tokens from node to node. At each node, the token becomes the Signaling or control provides or a data packet as user data includes, stored, evaluated and either to the local data user of the modem or otherwise forwarded to the next node in the network. The time required to store, evaluate, and retransfer a token is, reduces the effective net data transfer rate of such a network considerably, if every node is always online.

According to the invention are only certain nodes are programmed to suit any given Time are active, namely the node to which the token addressed is, as well as a minimum specified subset of nodes that are distributed along the network and are required to be a minimum Maintain signal amplitude at all points of the network. When this subset of nodes is active, you get a beneficial balance between time delay and reduced net data transfer rate and an extended physical range and improved Error rate.

The Determination of identity the constantly active nodal points may be due to manual measurements of the attenuation between all nodes of the medium-voltage network can be achieved. Prefers The modems are equipped with circuits that measure the voltage amplitude and / or measure the signal-to-noise ratio and over a Network media access control level. The knots should be also be programmed so that they have a command that they are in one constantly holding active forwarding mode, even for Accept tokens or packets that are not addressed to them.

It then an algorithm can be performed that determines which ones Knots as constantly to be actively set, and a stream of commands all nodes output to the appropriate nodes as constantly active adjust. The algorithm is performed every time the configuration of the medium voltage network is changed, but this is a relatively rare Event.

Close nodes lying next to each other experience a data transmission speed, which is equal to the maximum network speed while continuing distant nodes still depend on reliable delivery with lower Error rate, albeit at a slower data transfer rate to be served. In principle, it is claimed that the described Arrangement of all distance restrictions removed from medium voltage communications.

The transmission line formed by the selected conductor and its neighbors is in itself a high bandwidth, low loss and low dispersion medium. Overhead lines cause losses due to skin effect and radiation The latter is relatively ineffective because the lines are non-resonant at most frequencies. In underground lines, losses occur due to the skin effect and loss tendency of the insulation, eg, the outer layer of plastic and the inner layer of semiconductor material.

The The present invention produces low electromagnetic emission and has low sensitivity to external noise, in particular when used with spread spectrum techniques. The energy levels can be due low cable-to-coupler loss as well kept low. The sensitivity to external Noise sources are proportional to the radiation, due to the reciprocity the modes with the lowest electromagnetic interference (EMI) even those are the ones opposite the most resistant to receiving external noise are.

For single-ended grounded mode (see 2A ), the two neighbors of the selected conductor act in antiphase to the central conductor for both the electrical and magnetic radiation modes. An observer at some distance would see a significant extinction of fields.

In symmetric modes, both far field cancellation and shielding interference of the grounded neighbors would occur. At transformer termination (see 2 B ), the coupling loss would be lowest, and the operating voltage levels could be kept relatively low, resulting in the lowest EMI levels. At throttle completion, the operating voltages would be slightly higher.

If the modems act as power amplifiers, can the operating voltage levels are kept to a minimum, that for a single section is required, reducing the radiation is further reduced.

One Data communication network according to the invention offers a capacity for very high data transfer speeds, e.g. of more than 10 Mbps. The couplers are all magnetic and electrostatic Devices with bandwidths that are at least several tens of megahertz reachable, when using magnetic and dielectric high frequency materials become. Transmission lines, which are not too lossy and have a minimal dispersion, can Transmit frequencies, exceeding 20 MHz. Such frequencies can for modems be used, which use different modulation schemes, and would even at a bit per Hertz high data transfer speeds result.

Also Basic bandwidth signaling can be used when data encoding long sequences of only-1 and only-0 eliminated. With connections between the sections that comprise a restoration (power amplifier), would be the bandwidth much bigger than it can be reached by passive connection of the sections.

The coupler according to the invention can with little or no interruption of power supply Customers are installed. The installation can also be done without suspension across from high voltages become. If gloved pipe fitters are used, the authorities can use the Attaching an inductive coupler to allow a cable while the Cable is in operation. Even if the authorities insist that Workers are not allowed to work on live cables the loop structure of the medium voltage network in residential areas disconnecting a single cable section without the power supply to interrupt the customers. For the relatively few capacitive coupler could a single short power cut will be needed.

The The present invention allows uninterrupted operation of a Data communication network even during a power cut. The operation lasts even during Interruptions of medium voltage power on.

The present invention has little or no impact on reliability of the electrical network. Inductive couplers have no interference modes, which affect the flow of energy. The few capacitive couplers with their fuses cause also no line fault.

In the embodiments of the 2A and 2 B For example, winding the coupler with a thicker wire would preclude its failure due to overcurrent and the use of industrial standard connections between the selected neutral and the coupler should minimize interconnect interference. If an open circuit occurs, it would leave (N - 1) / N, or in the illustrated case, 87.5% of the current carrying capacity intact. Since the cable is usually operated far below its capacity of 200 A, such a disturbance should have no effect.

One Short circuit of the coupler affects data communications, but this would just reset the neutral to its original state. Consequently, the power grid is not adversely affected.

One Short circuit of the neutral or other part of the coupler to earth no influence on the MS line, because your neutral is connected to the grounding rod nearby. A disturbance of the magnetic circuit, open, short circuit or saturation, would have no effect on the Supply of electrical energy or the safety of the system.

The Couplers use only passive components, giving a virtually unlimited life includes. The inductive coupler can be any suitable transformer or inductor.

at In passive implementation, the inductive couplers use only passive ones Components, e.g. wires which are wound around magnetic cores, and these have no wear mechanisms. The capacitive couplers also have no wear mechanisms.

The passive construction and the simplicity of installation of the inductive Couplers make a cost-effective solution for the Problem of coupling to medium voltage power distribution lines and their use as backhaul data channels ready. The installation time should be less than 15 minutes for the main one inductive coupler and the installation costs are minimal be.

Embodiments, using neutral conductors have a clear advantage over capacitive bridging couplers, which use the medium voltage conductors to transmit data. The The latter occur at least once on each transformer with the Medium-voltage line in contact and must stand the full interference voltages hold. For example, a coupler needs to be for a 15 kV rms phase-earth cable be tested for 125 kV BIL. That makes the capacitive coupler very bulky and expensive and adds Add many potential points of failure to the system.

It should of course Be that different alternatives and modifications by the expert can be conceived. The present invention is intended to cover all such alternatives, modifications and variants falling within the scope of the appended claims.

Claims (59)

Device for facilitating communication a data signal over a power transmission cable, full: a first winding for coupling the data signal via a Head of power transmission cable and a second winding inductively coupled to the first winding, for coupling the data signal via a data input. The device of claim 1, wherein the conductor is a is the first center conductor of the power transmission cable. Apparatus according to claim 2, wherein the first winding connected in series between the first center conductor and a ground is. Apparatus according to claim 2, wherein the first winding between the first center conductor and a second center conductor of the power transmission cable in Row is connected. Apparatus according to claim 4, wherein the data signal differentially by the first center conductor and the second center conductor is sent. Apparatus according to claim 5, comprising a core With: a first area near the first center conductor and a second area near the second center conductor, in which the second winding is wound around part of the core and in which the second winding has a first current in the first center conductor induced in a first direction and a second current in the second center conductor in a second direction induced by the first direction is opposite. The device of claim 6, wherein the core is topographical as figure "8" without contact at the crossover point the "8" is configured. Device according to claim 7, the first one Area includes a first loop of the figure "8", in which the first conductor is passed through the first loop, the second one Area comprises a second loop of the figure "8" and wherein the second conductor is passed through the second loop. Device according to claim 7, the first one Area comprises a first gap in a first loop of the figure "8", the first conductor is guided through the first gap, in which the second area has a second gap in a second loop the figure "8" includes and in which the second conductor is passed through the second gap. The device of claim 4, wherein the first center conductor and the second center conductor are substantially parallel to each other in the energy transfer are cables. The device of claim 4, further comprising a core comprising, wherein the first winding comprises: a grounded center tap; one first area connected to the first center conductor which is in a first direction wound around the core and grounded to a Center tap is connected and a second, with the second center conductor connected area, in a second direction wrapped around the core and connected to the grounded center tap is. Device according to claim 4, the energy transmission cable has a plurality of neutral conductors, which are substantially parallel to each other, wherein individual of a first subgroup of the plurality Neutral conductor with individual of a second subgroup of the plurality Alternating neutral, wherein the first center conductor the first subgroup of the plurality comprises neutral conductors and in which the second center conductor is the second subgroup of the plurality of neutral conductors includes. Apparatus according to claim 4, comprising: one around a part of the power transmission cable arranged magnetic coil core, being the first center conductor and the second center conductor to a common termination element downstream of the magnet coil core are connected and the first one Winding to the first and the second center conductor upstream of the Magnetic coil core is connected. Apparatus according to claim 13, wherein the first and the second winding is inside a balun transformer. Apparatus according to claim 2, comprising an open magnetic core includes: a first leg close to and perpendicular to the first center conductor is arranged; a second leg, close to and perpendicular to a second center conductor of the power transmission cable is arranged; and a third thigh that is between the first leg and the second leg is to the the first winding is wound. Apparatus according to claim 2, comprising: one first magnet coil core with a gap through which the first center conductor guided becomes, a second magnet coil core with a gap, through a second center conductor of the power transmission cable is guided, in which the first winding around a part of the first magnet coil core and a part of the second magnet coil core is wound. Apparatus according to claim 2, comprising: a third winding for coupling the data signal over a second center conductor of power transmission cable and a fourth winding, which is inductive with the third winding coupled to couple the data signal via the data input, in which the data signal on a first path over the first center conductor, the first winding and the second winding and on a second Path over the second center conductor, the third winding and the fourth winding wanders and wherein the first path is parallel to the second path is. Apparatus according to claim 2, wherein the data signal a first data signal and wherein the device comprises: a third winding for coupling a second data signal via a second center conductor of the power transmission cable and a fourth winding, which is inductive with the third winding coupled to couple the second data signal to a second one Data input. The device of claim 1, wherein the conductor is a Phase conductor of the power transmission cable is. The device of claim 19, wherein the phase conductor a part of a medium-voltage network of the power distribution system is. Apparatus according to claim 19, comprising a core, through which the phase conductor is guided, wherein the second winding is wound around a part of the core. The device of claim 21, wherein the core has a Air gap has. Apparatus according to claim 19, which is a capacitor in series between the second winding and an earth. Apparatus according to claim 19, which provides overvoltage protection includes, which is connected in parallel to the second winding. The device of claim 1, comprising: one first modem with a first, to the data input of the second winding coupled input and with a second input for the more Coupling the data signal; and a second modem with a first, coupled to the second input of the first modem input and with a second input for the further coupling of the data signal. The apparatus of claim 25, wherein the first modem and the second modem are configured in alternate coupling. Apparatus according to claim 25, which is a data router includes, which is connected between the first modem and the second modem is. Data communication network via an energy distribution system is realized that a power distribution cable with a phase conductor comprising: an inductive coupler for coupling a Data signal over the phase conductor and with a data input for further coupling the data signal; and a capacitive coupler between the phase conductor and a ground near one end of the power transmission cable is connected to. Absorbing reflections of the data signal. Data communication network according to claim 28, in which the inductive coupler is close to a distribution transformer the power distribution system is located, wherein the distribution transformer has a power line output and the data communication network a capacitor for coupling the data signal between the data input and the power line output. The data communications network of claim 28, wherein the phase conductor is part of a medium-voltage network of the power distribution system. The data communications network of claim 28, wherein the end of the power transmission cable at a medium voltage output terminal of a high voltage to medium voltage transformer of the power distribution system. The data communications network of claim 28, which a node extending between the capacitive coupler and the Earth, for coupling the data signal between the phase conductor and a second data input. The data communications network of claim 28, wherein the inductive coupler has a current transformer with a to the Data input coupled winding includes. A data communication network according to claim 33, in which the current transformer comprises a core through which the phase conductor guided will, and the winding being wound around a part of the core becomes. The data communications network of claim 34, wherein the core has an air gap. A data communication network according to claim 33, which a capacitor in series with the winding and the data input includes. A data communication network according to claim 33, which a surge protection includes, which is connected in parallel to the winding. The data communications network of claim 28, wherein the capacitive coupler comprises: a capacitor, one RF isolation transformer, a fuse, one Derivative resistance and a terminator with a Resistance approximately equal to a characteristic impedance of the Power transmission cable is. Data communication network via a power transmission system is realized and a first area with a first center conductor and a second region having a second center conductor, full: a first coupler for inductively coupling a data signal over the first center conductor and with a data input for further coupling the data signal; and a second coupler with a Data input coupled to the data input of the first inductive coupler is and for inductive coupling of the data signal over the second center conductor. A data communication network according to claim 39, in which the first area a first power distribution cable on a first Side of a power distribution transformer comprises and in which the second area a second power distribution cable on one second side of the power distribution transformer. The data communication network of claim 40, wherein the power distribution transformer has an output power line and wherein the data communications network comprises a capacitor between the data input of the first inductive coupler and the output power line for coupling the data signal to the output power line. The apparatus of claim 40, comprising: a first mode having a first input coupled to the data input of the first coupler, and a second input for further coupling the data signal; and a second modem having a first input coupled to the second input of the first modem and a second input for further coupling the data signal. Device according to claim 42, wherein the energy transfer transformer has an output power line and wherein the data communications network a capacitor between the second output of the second modem and the output power line for coupling the data signal to the Output current line includes. Data communication network via an energy distribution system is implemented, which is a power transmission cable having a phase conductor, comprising: an inductive one Coupler having a first input for coupling a data signal over the Phase conductor and with a second input for further coupling of the data signal. The data communications network of claim 44, wherein the inductive coupler is a radio frequency (RF) transformer. The data communications network of claim 44, wherein the data communication network comprises a capacitor associated with the first input and the phase conductor is connected in series. The data communications network of claim 46, wherein the power distribution system includes a step-down transformer, in which the inductive coupler is close to a secondary side winding of the step-down transformer and wherein the data communications network comprises a component, which has an impedance which, when passing through the inductive coupler is approximately equal to a characteristic impedance of the power transmission cable is. The data communications network of claim 47, wherein the component is a modem. A data communication network according to claim 44, in which the energy transfer system a transition between a catenary and an underground cable, in which the underground cable has a characteristic impedance that lower than that of the catenary, and the Inductive couplers located on the overhead line close to the transition located. A data communication network according to claim 44, in which the inductive coupler has a first current in the phase conductor induces a first direction, the data communication network a second inductive coupler for coupling the data signal over a second phase conductor of the power transmission cable includes and wherein the second inductive coupler is a second current in the second phase conductor in a direction induced to is opposite to the first stream. The data communications network of claim 44, wherein the inductive coupler is located on a line which is a primary-side Winding a distribution transformer of the power distribution system fed. A data communication network according to claim 44, in which the power distribution system is a component. between the phase conductor and contains a soil, in which the component has a characteristic impedance that is smaller is the one of the power transmission cable, and wherein the data communication network further comprises a throttle in series with the component. The data communications network of claim 52, wherein the component is selected from the group consisting of a power factor correction capacitor and a Power Line Communications (PLC) Condenser exists. The data communications network of claim 52, wherein the choke comprises a magnetic core that extends by a length of Wire is arranged, which connects the component with the phase conductor. A data communication network according to claim 44, in which the inductive coupler transmits a first current in the first phase conductor via a induced first winding, the data communication network a second inductive coupler for coupling the data signal over a second phase conductor of the power transmission cable includes, wherein the second inductive coupler is a second current in the second phase conductor induced a second winding and being the first winding and the second winding are parallel to each other. A data communication network realized via a power distribution system comprising a phase conductor having a first region on a first side of a switch and a second region on a second side of the switch, comprising: a first capacitive coupler for coupling a data signal over the first region and a data input for further coupling the data signal and a second capacitive coupler having a data input coupled to the data input of the first capacitive coupler , and for coupling the data signal over the second area, wherein transmission of the data signal between the first area and the second area is maintained when the switch is open. System for identifying one of a plurality of neutral conductors of a power transmission cable, full: a receiver for measuring a signal from a selected neutral of the power transmission cable and an indicator for a strength the signal, the signal being sent to the selected conductor at a first Point on the power transmission cable is created and the recipient the signal at a second point on the power transmission cable, which is distant from the first point measures. The system of claim 57, comprising: a Ferrite coil with a radial slot through which the neutral conductor guided will, and a winding around a part of the ferrite coil wound and connected to an input of the receiver, in which the signal from the selected one Neutral over the ferrite coil is inductively coupled. A system according to claim 57, including an inductive coupler by which the signal is applied to the selected neutral conductor on the first point is created.