DE1465459A1 - Telecontrol device - Google Patents

Description

Telecontrol Device The present invention relates to a device for the remote transmission of electrical signals via a distribution network for electrical energy.

With the current state of the art, it is possible to transmit signals via the energy distribution network, provided that the signals essentially follow the direction of the energy flow. Under the name ripple control systems, also referred to as central remote control systems or network command systems, devices are known with which control commands and messages are transmitted from a central transmission point via the power network to individual or a large number of receiving points distributed in the low-voltage network. Today these systems all make use of the principle of audio frequency superimposition; audio frequency voltages from a few components of the mains voltage are superimposed on them and transmitted by the power lines and mains transformers in basically the same way as the power current.

The reasons why tcnfrequente signals are practically only in the direction energy distribution are more economical and technical Art. The signal streams are not only from the receiving devices, but also from added to the energy consumers of the network. Despite being relatively lower Signal voltages are therefore considerable audio frequency powers and corresponding Expenses required. These are economically justified in a single central transmitter, but not in a large number of branch offices. The technical The reason lies in the structure of the energy distribution network, which decreases from the inside out Conductor cross-sections and fuse rated currents, but if you have audio frequencies Signals ahead. wanted to transfer from outside to inside, then the weakest conductors would have to and fuses carry the strongest frequency currents, from the standpoint of voltage drop and this is not beneficial to the heat of electricity, in most cases even quite impossible. on the other hand there has long been a need for signal transmission via the energy distribution network $ also against the direction of flow of the gas, e.g. for feedback in ripple control systems as well as for signaling autonomous state changes, such as switch trips, Malfunction reports.usvr and fair the transmission of telecommunications signals. Rationalization too The energy billing by reading meter readings calls for an economic one Transmission of signals via a. Existing heavy current network from the outside Inside.

If, despite a considerable need, no solution has yet been implemented was able to, it is due to the difficulty of the task, a well-known suggestion is that, similar to ripple control, the network at a central Place an audio-frequency voltage superimposed on each of the external reporting points the audio-frequency conductance of a series resonant circuit connected to the network is changed rhythmically. The periodic fluctuation of the overall sound frequency conductance of the network, viewed from the central receiving point, serves as a criterion for receiving a signal, however, there is a major disadvantage of this solution in the difficulty of generating a sufficiently powerful signal with portable Effort at the exhibition sites. The desired change in conductance must be done in one Sufficient size ratio to the natural fluctuations of the audio frequency Mains conductance that results from the constant changes in the network load surrender, only under this condition gives the whole te fluctuation frequency of the audio-frequency mains conductance sufficient selectivity to avoid false displays to avoid accidental fluctuations in the audio-frequency network conductance. To the Size of the audio-frequency network conductance at the central signal receiving point: through to be able to sufficiently influence the series resonance circuits of the branch offices the larger the load, the larger these series resonance circuits are dimensioned and is the series impedance of the network. The applicability of this solution is thus strictly limited for economic and technical reasons.

In ripple control technology, it is known per se, damped vibrations by connecting a capacitor to the mains in the cycle of the single or double Generate network frequency. This is a central transmitter, the one Supply a large number of receivers distributed in the low-voltage network with signal streams got to. This requires an essentially fixed and common for all recipients, transmission frequency that is not too high, as well as a high transmission power. To these demands to be sufficient, a relatively large capacitor must be used in the known devices are used, which are either connected in series with matched dressing coils or together with the leakage inductance of the associated supply transformer the desired transmission frequency is more or less precisely tuned.

The subject differs from the known ripple control devices of the present proposal in itself by the reversal the Task: The signals are from the periphery of the network to the center directed, i.e. mainly to be transmitted against the direction of flow of the network energy. The present invention therefore does not relate to the known field of ripple control, but a technology that has not yet been realized and for which there is no general one introduced more detailed designation there.

The aim of the present invention is to overcome the disadvantages of the known Avoid facilities and provide a solution for the task at hand, which can be fully realized technically and economically.

A device for the transmission of signals over an alternating current power distribution network by superimposing the AC mains voltage with an AC signal voltage, whose Frequency is a multiple of the frequency of the AC mains voltage and the through Connection of a transmitter capacitor to the alternating current network in time with the simple one or double the mains frequency is generated, consists of at least one signal transmitter and a signal receiver and has the characteristic features of the invention, that a high-pass filter is arranged on the input side in the signal receiver, its Cutoff frequency at most equal to the lowest possible frequency of the signal alternating voltage is, and that the frequency of the signal alternating voltage generated by the signal generator depending depending on the location of the signal transmitter in the network, any values above this Has cutoff frequency. According to the proposal, the one in ripple control technology is used generally known principle of the fixed transmission frequency deviated and instead whose leave the frequency of the signal voltage to chance. This can make the claim looking for a cheap signal generator will be perfectly met because yourself this eliminates the need for any means for frequency tuning. By eliminating of damping abatement means is only sufficient to generate the alternating signal voltage a capacitor of at most a few gF per signal transmitter, a relatively powerful one To obtain signals whose strength is in terms of amplitude above the level of most interfering waves lies. Depending on the data of the network transformers and the type and length of the power lines, in particular between the signal generators and the feeding mains transformer signal frequencies that fluctuate within very wide limits, namely between around 2000 and 20,000 Hz. These signal frequencies are therefore certainly higher than that Frequencies of those harmonics of the mains voltage whose amplitudes are of the order of magnitude of the signal amplitudes.

The invention is explained in more detail below with reference to the drawing, The figures show: FIG. 1 a diagram of a telecontrol device, FIG. 2 a diagram of FIG superimposed signals, FIG. 3 shows a receiver detail, FIG. 4 shows another diagram of a Telecontrol device and FIG. 5 shows a group of diagrams. In the Fig, 1 is a low voltage network 1 with phase conductors 2, 3 4 and a neutral conductor 5 shown, which is from a transformer 6 with low-voltage windings 7 and Medium voltage windings 8 is fed. The transformer is fed Via phase conductors 9, 10, 11 of an intermediate voltage line 12 from a busbar 13 one spatially distant from the transformer 6, not further in the figure shown distribution station.

On the right in the diagram of FIG. 1, a signal generator 14 for the generation of signal waves in the cycle of twice the network frequency is shown. The signal transmitter 14 consists of a transmitter capacitor 15, a polarized relay (or resonance oscillator) 16 with a coil 17 and a changeover contact 18 with a movable contact tongue 19 and two fixed mating contacts 20 and 21. A control contact 22 is with the coil 17 and with a resistor 23 electrically connected in series. The series connection of the transmitter capacitor 15 with the changeover contact 18 is electrically parallel to the series connection of the coil 17 with the resistor 23. The signal transmitter 14 is connected on the one hand to the neutral conductor 5 and on the other hand to one of the three phase conductors of the low voltage network 1, e.g. to the phase conductor 4 The signal transmitter 14 works in the following way: In order to give a signal , the control contact 22 is closed, either manually or by any device that is intended to trigger a remote action or whose position is to be monitored, for example by a signaling consumer knife. As a result, the coil 17 of the polarized relay 16 is connected via the resistor 23 between the phase conductor 4 and the neutral conductor 5. The movable contact tongue 19 then leaves the rest position shown and oscillates back and forth between the fixed mating contacts 20 and 21 in time with the mains frequency. In the positive. Half-wave of the mains voltage touches them z.8. the counter contact 20, the counter contact 21 in the negative half-wave. The frequency of these oscillations can be calculated according to the known resonance formula from the capacitance of the transmitter capacitor 15 and the resulting inductance t of the network, based on the transmitter location.

As mentioned, this frequency can have any value within wide limits accept; but in all conceivable supply networks it is not below about 2000 Hz. The initial amplitude of each of the signal voltage waves is at the encoder location theoretically equal to twice the phase voltage. 7n Reality is the vibration strongly damped, so that the initial amplitude is already lower than the theoretical value is and continues to decrease sharply with the distance from the encoder location, in FIG the general character of the signal oscillation and its position in relation to the voltage curve U4 and the current curve 1 4 of the phase conductor 4 indicated. To be as strong as possible To receive a signal, the polarized relay 16 is set so that the mating contacts 20 and 21 of the movable contact tongue 19 as close as possible to the voltage maximum be touched. By changing the ratio of the reactance of the coil 17 to the Resistance of the coil 17 and of the resistor 23 can be the Affect the period of oscillation relative to the line voltage curve U4. At the same time For this purpose, capacitors can also be added to the excitation circuit of the polarized Relays can be inserted.

From Fig. 2 it can also be seen that the signal generator 14 generated, very brief signal oscillation does not have a fixed phase relation assumes the line current I4, but compared to the line voltage U4; because between the line current 1 4 and the line voltage U4 is a phase shift, whose The size depends on the changing nature of the network load. On the other hand, she has Mains voltage U4 regardless of the mains load on the entire slope of the low-voltage line almost the same phase position. When the signal generator 14, the signal waves according to the Fig. 2 is generated in the vertices of the line voltage curve U4, the signal wave is consequently also at the receiving point close to the vertices. In FIG. 1 is still a signal receiver 24 is shown, the input 25 of which via a coupling transformer 26 is connected to the low-voltage network 1. The coupling transformer 26 is preferably located in the neutral conductor 5,. but he could also, as indicated, in the phase conductor 4 of the low-voltage network 1 or even in the phase conductor 11, the Medium-voltage network 12 (or in another of the drawn phase conductors, depending on which phase conductor the signal generator 14 is connected to). All Three examples of the coupling of the signal receiver 24 is the series coupling basis, i.e. one primary winding of a coupling transformer is in series connected with a network conductor. In principle, one could use the signal receiver 24 Similar to the signal generator 14 also connect to the network in parallel coupling, This would be easily possible on the low-voltage side, since it is at the receiving point the ratio of the signal voltage to the mains voltage is greater than that for Series coupling decisive ratio of the signal current to the mains current. On the On the other hand, the medium-voltage side is the signal voltage in relation to the mains voltage because of the high leakage reactance of the transformer 6 at the signal frequency and the low impedance of the medium-voltage network 12 is much smaller, while the current ratio is basically the same on both sides of the transformer 6. On the medium voltage side Series coupling is therefore preferable because it has a very low signal power gets by. But it also has advantages on the low-voltage side, in particular in a four-wire network according to FIG. 1, because then a single coupling transformer 26., which also only has to be dimensioned for the neutral current. enough. In the Figures are indicated throughout the series coupling of the signal receiver. Basically however, the receiver versions described below are for series and suitable for parallel coupling "The signal receiver 24 shown in FIG. 1 comprises a high pass filter 2? consisting of an electrically in series with the input 25 arranged capacitor 28 and a choke coil 29, also a rectifier 30 in a bridge circuit, a smoothing capacitor 31e a DC receiving relay 32 with a normally open contact 33, and. . two equipped with working contacts 34 and 35 Delay relays 36 and 37, which are connected to an evaluation part 38, The high-pass filter 27 is calculated for a cut-off frequency that is smaller than the lowest signal frequency, e.g. for 2000 Hz, the mains frequency and their harmonics, which in practice occur at most up to about the fortieth order are therefore not allowed through by the high-pass filter 27, those by the high-pass filter 27 The signal voltages passed on to the rectifier 30 have a curve such as it is shown in FIG. 2 as U3Cy ,, which corresponds to the coupling transformer 26 in the design of a current transformer, but has an air gap in the iron core. Of the Air gap has the task of saturation of the iron by the mains current when open Avoid secondary winding, because namely the secondary winding through the high-pass filter 27 of the receiver 24 is completed, it acts for the low-frequency mains current like an open winding, instead of the coupling transformer with air gap can also a . normal current transformer can be used, the secondary winding with a Burden is completed, which is electrically in series with a low-pass filter. The cutoff frequency of the low-pass filter is at most equal to the cutoff frequency of the high-pass filter 27 is selected.

When the control contact 22 is closed on the signal generator 14, both. For example, for 200 milliseconds (abbreviated: ms), a rapidly decaying signal oscillation is triggered at the apex of each of 20 successive half-waves of a mains voltage having a frequency of 50 Hz by the switching contact 18 working in rhythm with the mains frequency, whereby the DC relay 32 in the signal receiver 24 during 200 ms responds.

This pulse, which lasts for 200 ms, is initially through the first delay relay 36 for example 50 ms and through the second delay relay 37 truncated another 50 ms. The thus shortened pulse of 100 ms duration arrives now via the working contacts 33, 34, 35 of the relays 32, 36 and 37 to the evaluation part 38, the one for the evaluation of coded signals depending on the application of the telecontrol device can be formed in any known manner.

In most cases it is sufficient to filter out the signals dae_Hochpassfilter 27 to ensure interference-free reception of the signals. This is particularly true when the signal transmission only takes place within the low-voltage network 1 is carried out and in this no excessive interference waves are caused, especially by industrial energy consumers, or when the signal is given only takes place during a period of low network load, e.g. during the night.

If, on the other hand, the network has an unusually high level of interference in Frequency range # above approx. 2000 Hz, then for telecontrol tasks, which require a high level of transmission security, in the signal receiver 24 also High-pass filter 27 still further means for filtering the signal are used, Such means can e.g. the two downstream of the receiving relay 32 Be delay relays 36 and 37, the effect of which is explained in the following brief explanation becomes understandable.

A well-known type of interference voltage arises from particularly high currents Switching processes in the network. These interference voltages usually contain a whole spectrum different frequencies, including those above the cutoff frequency of the high-pass filter 27. They are therefore not separated from the signal by the high-pass filter; in addition they are often of high intensity. On the other hand, all switching processes have one thing in common Characteristic that they usually only appear sporadically and are of short duration, namely at most about 20 to 50 ms.

Interference voltages caused by switching operations can therefore lead to simple way can be rendered harmless by keeping in tact with the simple or twice the network frequency, i.e. at a time interval of 20 or 10 ms Trains of dampened signal oscillations the first 3 or 6 oscillations suppressed in the signal receiver, the entire duration of a signal pulse, consisting from the succession of several decaying ones sent out in the cycle of the mains frequency Vibration trains, so must be at least cut off in the signal receiver The initial part of the impulse must be longer than necessary for a reliable evaluation of the Sigral is. The truncation of the initial part of the received pulse takes place, as mentioned, for example by the two delay relays 36 and 37, or by any different, known electrical. tric or mechanical delay elements. Spurious waves as a consequence of Switching operations then no longer reach the evaluation part 38 of the receiving device, this also applies to interference waves such as those when switching on from capacitors in the network. Capacitors, for example, to improve serve the power factor, are probably iii regular or irregular at intervals, but never connected to the grid at the rate of the grid frequency. Completely different types of interference voltages can now e.g. through bad contacts in switches or line couplings and also by welding equipment, if these are switches or supply lines from larger energy consumers or large welding machines are involved, interference waves with a steep front occur, which are also allowed through by the high-pass filter. Against such influences the delay elements mentioned are ineffective because they are interference waves that lasts for seconds, minutes or even hours, your amplitude is generally much weaker than that of interference from switching operations and also weaker than the amplitude of the signal oscillations.

While the signal oscillations have only moderate amplitudes in the vicinity of the mains voltage maximum and decay within a maximum of about one millisecond, during the ten times longer ren duration of an i @ etzspanr @ ur.r @ = @@ xalbrreile many interference voltage waves appear. one now di; over -, s: 'Le ^ hpassfilter running <or span- Simply rectify the voltages, smooth :: @ n x -: - 3; den: receiving ring 12 zttL- , lead, edi # -3 in the figure; Lst @. @ _ _ ;, is, s ^ @: @ ö.a ° c for Responding to the mean value over time of all voltage amplitudes passed by the high-pass filter 27 is decisive. Even with a much smaller amplitude of the interference voltages compared to the signal voltage, these interference voltages could cause the receiving relay to respond.

To shield the signal receiver 24 from this type of interference voltages further means are therefore proposed below. If the amplitude is a Interference voltage at the output of the high-pass filter is much smaller than the amplitude the signal voltage, then it is enough to be in series with the rectifier mentioned above 30, i.e. in the excitation circuit of the receiving relay 32, an electrical threshold, z, H. to switch on a current gate with a fixed voltage threshold represents z.8. the Zener diode. In order for the receiving relay to respond, it must then be on the DC side of the rectifier a voltage occur that at least equal to the sum of the constant Zener voltage, from the response pressure of the Relay and from the voltage drops of the rectifier and the zener diode is. By a suitable choice of the Zener voltage and the other data, it can be achieved that all interference voltage amplitudes that are smaller than the minimum signal voltage, remain ineffective, In Fig. 3 is an embodiment of the signal receiver 24 illustrates, which differs from that of FIG. 1 by the arrangement of a Zener diode 39 differs after rectifier 30, The zener diode acts like a negative bias in series with the rectifier. Interference voltages, which do not exceed the threshold value of this pre-tension, the so-called Zener tension, therefore remain ineffective.

In the presence of interference voltages, their greatest amplitudes, only are insignificantly smaller than the smallest amplitudes of the signal voltage is sufficient the threshold value method does not meet the high demands placed on transmission security more in all cases; because it is difficult to set the threshold in. the low Distance between the highest interference voltage peaks and the lowest signal voltage $ u lay. Here it proves to be expedient to place the direct current circuit after the rectifier 30 to block in those time intervals in which only interference waves, but none Signal waves can occur.

This could be done by a controllable electromechanical current gate arranged in the excitation circuit of the receiving relay 32. a polarized relay with parallel-connected external contacts on the type of the polarized relay 16 in the signal generator 14, wherein the relay winding is connected to control the contact-making point in time with a resistor in series to the same power conductor, such as the signal generator 344 for temporarily blocking, however, the receiver direct current circuit is advantageously a contactless power gate. An arrangement suitable for this purpose is shown in FIG. One recognizes again the low voltage network 1, the signal transmitter 14 and the signal receiver 24. As far as the parts of this arrangement correspond to those shown in FIG. 1, they are provided with the same reference numbers. The signal transmitter 14 according to FIG Generation of. Signal oscillations in the cycle of the simple mains frequency, whereby the signals can optionally be superimposed on the positive or negative half-waves, i.e. homologous values of the mains alternating voltage, preferably peak values thereof. It differs from the signal transmitter 14 according to FIG and a selector switch 41 with two selector contacts 42 and 43, and a discharge resistor 44 are arranged in the condenser circuit.

If you choose the resistance values of the resistors 23 and 40 among themselves equal so that they form a symmetrical voltage divider so will the coil 17 of the polarized relay 16 is the same when the control contact 22 is closed strongly energized, but with reversed polarity, depending on the selector switch 41 is on dialing contact 42 or on dialing contact 43. A contact between the contact tongue 19 and the mating contact 20 takes place, for example, during the positive Half-waves of the mains voltage when the selector switch 41 on the selector contact 42, or during the negative half-waves when the selector switch 41 is on the selector contact 43 is switched.

Wen.i the Kontaktsunge 19 touches the mating contact 20, the transmitter capacitor 15 charged via the mains to the peak value of the mains voltage, whereas he himself when the mating contact is touched, the contact 21 is discharged via the discharging resistor 44. the The duration of a signal pulse corresponds to the closing duration of the control contact 22. Of course, the control contact 22 and the selector switch can also be omitted 41 can also be used as a control contact, in this case the selector switch 41 take a middle position in the rest position and only for the delivery of plus or minus pulses briefly swung out to one side or the other.

For the adjustment of the starting point of the signal wave to one very specific point of the mains voltage half-wave can besides the appropriate choice the resistance values 23 and 40 also have H11fs capacitors in the excitation circuit of the polarized relay 16 can be used! be it in series or parallel to the coil 17 or to resistors 23 and 40.

In FIG. 4, the signal receiver 24 can also be seen in a form that has been expanded in terms of circuitry compared to FIGS. 1 and 3. In addition to the high pass filter 27 and the rectifier 30, the signal receiver 24 includes according to the Fig 4 following additional agents. A e as a controllable stream gate acting triode 45 having a cathode 46, a grid 47 and an anode 48 whose input side is connected to the rectifier 30, the plus pole of which is connected to the grid 47 and the minus pole via a bias voltage source 49 to the cathode 46, the anode 48 is electrically connected in series with an oscillating circuit 50t consisting of the primary winding of a transformer 51 and a capacitor 52, the The anode 48 is fed by a partial winding 53 of a transformer 54t whose primary winding 55 is connected in series with an unsaturated choke coil 56 and whose closed iron core is saturated by the sinusoidal magnetizing current of the choke coil 56.

In the working circuit of the triode 45 is between the Teilwicälung 53 and the resonant circuit 50, a rectifier 57 inserted in. Bridge circuit, its positive pole on the anode 48, and its negative pole on the cathode 46.

To explain the mode of operation of this part of the receiving arrangement, the upper seven of the thirteen diagrams in FIG. 5 are used below. The curve labeled U56 represents the time course of the line voltage between the phase conductor 4 and the neutral conductor 5 to which the choke coil 56 is connected. The curve labeled I56 shows the shape and phase length of the magnetization current in the choke coil 56. If the air gap in the iron core of the choke coil 56 is correctly dimensioned, the magnetization reversing current I56 is almost sinusoidal and lags 90o compared to the voltage U56. This magnetizing current I56 also flows through the primary winding 55 of the transformer 54. By appropriately dimensioning the primary winding 55 and the closed iron core of the transformer 54, it can be achieved that the current i56 generated by the sinusoidal current i56. magnetic flux as a result of saturation DE® core has a trapezoidal shape according to graph 055 is obtained, so in the sub-winding 53 a voltage is induced, the known saturation peaks soft alternating polarity gemäe® curve having ü53. On the direct current side of the rectifier 57 and the anode 4.8, this voltage appears as a sequence of positive peaks with a frequency of 100 Hz according to graph U57.

The negative bias voltage of the grid 47 is selected so that even during the periodically occurring positive anode voltage peaks, no anode current flows as long as no signal or interference voltages are present. In the case of unsteady network conditions, however, interference voltages of longer duration can pass through the high-pass filter 27, for example according to the irregular waves which, apart from the regularly recurring spikes of a minus signal, are indicated in graph U30. With sufficient strength, these interference voltages occurring as positive excursions on the grid 47 can trigger short anode current surges with a frequency of 100 Hz during the periodically repeating voltage increase of the anode 48. These shocks also flow through the oscillating circuit 50, but cannot cause it to oscillate because the impulse frequency 100 Hz deviates too far from the natural frequency 50 Hz of the oscillating circuit 50.

if, on the other hand, a signal is sent by the signal generator 14, for example a minus signal, then a signal oscillation occurs on the negative half-waves of the mains voltage curve U56 (not shown in FIG. 5). In front of the rectifier 30, these appear as a sequence of rapidly decaying wave trains superimposed on the interference waves in the cycle of the mains frequency 50 Hz, as indicated in the curve U3 0-u. They also reach the grid 47 as positive voltage surges and trigger additional current surges off in the anode circuit. because their cycle matches the natural frequency of the resonant circuit 50, they cause it to vibrate. On the windings of the transmitter 51 then occur tensions, which according to the course ve U51 (_) run in phase opposition to the mains voltage U56, In the diagram of the anode current according to curve I 4.3 (-), the values from (Mi nut) signal. anode current impulses triggered at a rate of 50 Hz larger: amplitude shown than that of the interfering waves in the cycle shocks caused by 100 Hz., The tuning of the oscillating circuit However, 50 to the beat of the signal waves allows them to be screened out from the interfering waves that occur non-periodically or at a rate of 100 len even if the interfering waves have stronger amplitudes than the signal waves. Traps only a single signal, so no distinction from plus and minus signals may be required on the secondary winding of the transformer 51 directly or via an amplifier, direct direct or the like a receiving relay or a signal line be connected. This is shown in Fig. 4 is not particularly DAR posed. For a better understanding of the effect of the part described so far of the signal receiver 24 according to the Pig. 4 are now followed by a few more partly repetitive explanations. For safe separation of signals from interference voltages with a high level the output of the high-pass filter can be fed to the Sterer lattice of a verator tube are placed, the anode of which only during that time segment of the mains voltage half-wave voltage in which a signal oscillation can occur, i.e. in the vicinity of the peak value of the network pan # g . The tube over- It then takes on the role of a time-controlled current gate and an amplifier at the same time, an anode voltage that only has the appropriate setpoint for the tube in the vicinity of the apex of the mains voltage sine curve and can be much smaller or practically zero during the rest of the time through a transformer can be generated with a saturated iron core. Such a transformer, magnetized by a sinusoidal current, shows a trapezoidal course of the magnetic flux. Short-term voltage peaks in alternating directions occur during the short periods of change in the direction of flow. The duration of these peaks can be freely selected by the degree of saturation, and the height of the voltage peaks by the secondary number of turns . So that the voltage peaks fall at the point in time of the network peak, the sinusoidal magnetization atrom must be shifted by 90 ° compared to the network voltage. For this purpose, the saturated transformer can be equipped with an unsaturated inductor with an air gap in the. Iron core can be connected in series. If the unsaturated choke coil is much larger than the saturated transformer, which only has to deliver a low output, the magnetizing current remains practically sinusoidal despite the voltage peaks which are also induced in the primary winding of the saturated transformer To be able to check the presence of signal waves after the negative half-waves of the mains voltage, the voltage peaks of alternating polarity generated by the saturated transformer are rectified and fed to the anode of the tube. In series with the rectifier between the Nochpasofilter and the The grid of the amplifier tube is also a voltage source for the no- switch on generating a negative grid bias. Marriage the grid prestress becomes. so chosen "that the tube in the lower Part of the anodenetrom-aenode voltage characteristic is working. In the time intervals between the peaks of the anode voltage flows da = no or only a low anode current even if there is strong interference tensions come in over the Nochpasofilter and the grid rep raise accordingly. So incoming waves are only let through and amplified, rhyme them in. the short times around the positive and negative vertices the mains voltage wave occur. After smoothing the anode currents can. this directly to the excitation of a DC lais can be used. The mode of operation of the tube in the initial area of the characteristic curve has one Similar effect to the Zener diode in the one shown in FIG. refined example. Weak input voltages are not at all or relatively less amplified than those who Have exceeded minimum value: The most important property of the Arrangement with abruptly increased cup catch sensitivity at the moment the network epennunecheitelverte lies in the fact that interference voltages! which occur between the peaks of the mains voltage are unreasonable. If the interference voltages have the same or greater amplitude as the signal waves, it is advisable to send the signal waves only every second half-wave of the mains voltage, i.e. in the cycle of the single mains frequency, so that they can be matched to the mains frequency in the signal receiver To separate the resonance circuit from those interference voltages that are allowed through by the high-pass filter and the current gate circuit just described. This measure is based on the fact that the interfering waves with a high steepness caused by defective switch contacts or line connections, welding equipment and the like are by nature either not periodic at all or then most likely at the rate of the changes in the absolute values of the AC mains voltage, e.g., with 100 Hz, but are almost never modulated with 50 Hzi. If, as an exception, interference voltages should nevertheless be modulated with 50 Hz, their amplitudes would also have to exceed the defined threshold value.

Instead of the only mentioned DC relay in the anode circuit of the tube So it is best to arrange a parallel resonance circuit tuned to 50 Hz. This can be done in any known manner, with or without intermediate reinforcement an alternating current relay or, via a rectifier with smoothing means, a direct current relay be coupled as Rmpfangsrelais, interference voltages that are strong enough to to trigger an anode current at all, and that over a number of successive ones Half-waves of the mains voltage occur .. bring the to the simple mains frequency tuned resonance circuit does not oscillate because anode current surges as a result of Interference voltages - if at all - a periodicity of the value of have twice the line frequency.

In order for the desired (e.g. 50 Hz) selectivity to be present, the receiving circuit is up to the 50 Hz oscillating circuit against the interference and signal voltages, which occur during the positive and negative half-waves of the mains voltage, behave completely neutrally, only waves that already have a 50 Hz periodicity in the network and pass through the high-pass filter, may reach the receiving relay. For this reason, as mentioned, the Amplifier triode rectifiers can be used in two-way or bridge circuits. This creates a 50 Hz period artificially generated by the receiving arrangement avoided.

The receiving arrangement described so far picks up incoming signals in the cycle of the simple mains frequency, regardless of whether they are carried by the positive or negative half-waves of the mains voltage. For example, with remote meter reading according to the meter reading principle, increased transmission reliability can be achieved without having to go to coding by assigning the signal of the positive half-wave to the information "Fixed amount used" and the signal of the negative half-wave to the information "Fixed amount not used", or vice versa. . In other applications, however, where a large number of different information makes coding imperative can also be an increased Uebertragangssicherheit be achieved by assigning two NEN signals various of the drawing and separation steps This known happens in Doppeltontelegraphie, - Unlike to this kön- NEN instead of different frequencies for the character and separation steps proposed according to the signals of the positive half-waves are assigned to the characters steps, and the signals of the negative half-waves of the separation steps, or vice versa.

To implement this proposal, the previously described neutral arrangement of the receiver according to FIG. 4 can be assumed, but the catch relay which responds to signals of the positive or negative half-waves (only mentioned in relation to FIG. 4) is omitted. In its place are two similar sets of circuit elements for separating the two different signals, which during the positive or, respectively. negative half of Hetzspannung werden- Given the two different signals to advertising bzw.- hereinafter called Plus Signal Minus signal designates. The two sets of circuit elements for separating the plus and Wmus signals each consist, for example, of an additional controllable current gate, an additional 50 Hz parallel resonance circuit, an additional winding on the saturated transformer and an Em $ -tag relay, the receiving relay of each of the two sets can be an alternating current relay or a direct current relay fed via a rectifier with a smoothing capacitor, which is coupled with or without intermediate amplification to the associated 50 Hz resonant circuit. These two sets of. In the following, building elements are also designated in more detail by the addition of "plus" or "minus" in order to distinguish them from one another and from the analogous elements of the previously described "neutral" sentence.

4 shows a current gate (a triode) 58, the so-called "Minue Triode", with a cathode 59, a grid 60 and an anode 61; This U "ient for receiving the minus signals. The cathode 59 is connected to the cathode 46 of the" neutral "triode 45, while the grid 60 is connected to the secondary winding of the transformer 51 to which the cathode 59 is also connected via the bias voltage source 49 The anode 6 # 1 is connected in series with an oscillating circuit 62 which is tuned to the single mains frequency and which consists of a transformer 63 with a primary winding 64 and a secondary winding 65, as well as a capacitor 66 connected in parallel to winding 64. The anode voltage for the triode 58 is supplied from a winding 67 of the saturated transformer 54 which is connected on one side to the oscillating circuit 62 and the other hand to the cathode of the 59th in a departure from the otherwise I similar "neutral" set of switching elements constructed (triode 45 order), however, is in the case of the minus triode 58, a rectifier is not connected upstream of either the grid 60 or the anode 61. Both on the anode 61 and on the Git Therefore, voltages with positive and negative polarity occur ter 60, if the negative bias of the grid 60 is initially disregarded. The connection between the grid 60 and the secondary winding of the transformer 51, as well as between the anode 61 and the winding 67, is chosen so that in the case of a minus signal, the grid and the anode become positive at the same time. The curve U51 (-) (FIG. 5) shows the voltage occurring at the grid 60 when there is a minus signal on the secondary winding of the transformer 51. Its positive peak value occurs at the same time as the positive voltage peaks in the winding 67 according to curve U67, which also appear at the anode 61. As a result, the anode current impulses shown in curve I61 (-) arise in. The voltage U65 (-) occurs in the secondary winding 65 of the transformer 63 A direct current relay 70, which thus responds to the minus pulses of the signal generator @ 14, The direct current relay 70 does not react to the plus signals because the * corresponding voltage U51 (+) (not shown in FIG. 5) compared to U51 (-) is shifted by half a wavelength, the positive half-wave of U51 (+) therefore does not coincide with the positive, but with the negative peaks of the voltage curve U67, An anode current I61 (+) (also not shown in FIG. 5 ) thus does not come about, so there is no alternating voltage on the secondary winding 65 and therefore also no direct voltage on the relay 70 @. A structure similar to that of the recording of the Mi. The circuit group serving nus signals also has the circuit part set up for receiving the plus signals. A grid 71 of a plus triode 72 is connected in parallel with the grid 60 of the minus triode 58. On the other hand, an anode 73 of the triode 72 is connected to the associated winding 74 of the saturated transformer 54 in such a way that the alternating positive and negative voltage peaks according to curve -U74, compared with the anode 61, reach the anode 73 in push-pull mode. A. (interspersed with interfering waves) plus signal gives a current curve in the new-Itral anode circuit of the triode 45, curve U48 (+) and in the secondary winding of the "neutral" resonant circuit transformer 51 a voltage curve according to curve U51 (+). This voltage also occurs at the grid 71: The positive half-waves at the grid 71 coincide with the positive voltage peaks at the anode 73 in the case of the plus signal. it should be noted that a common diagram is drawn for U53, U67 and U74 in fig: 5: The anode 73 therefore carries a voltage U74 which, compared to the curve -U ,,,, has the opposite polarity, with plus -Signal conditions comes an anode current according to curve I73 (+), the one in the anode circuit the resonant circuit 75 arranged in the triode 72 excites at its natural frequency which corresponds to the simple network frequency; A relay 80 fed by a winding 76 of a resonant circuit transformer 77 via a rectifier 78 with a smoothing capacitor 79 thus responds to the plus signal and only to this. For the sake of completeness, it should be mentioned that the contacts of the relays 70 and 80 are included in the circuit of an evaluation part in an analogous manner to the contact 33 of the receiving relay 32: The TriodEn45, 58 and 72 are operated in the lower part of the anode-atom-anode voltage characteristic curve; The negative grid voltage is chosen so that an anode current only flows when the negative bias voltage is superimposed on a positive voltage that exceeds a certain threshold value. The bias source 49 can be used in common for all three triodes. As such, in the exemplary embodiment according to FIG. 4, there is a rectifier 81 in a bridge circuit with a smoothing capacitor 82. The rectifier 81 is fed via a transformer 83 from the network.

The mode of operation of the part that distinguishes the polarity of the signals the receiver circuit according to FIG. 4 is shown again in the following for the sake of clarity in slightly different words briefly summarized.

The grid of the plus triode and the minus triode are connected in parallel and coupled to the neutral resonant circuit 50 with such polarity that the grid becomes positive in the event of a plus signal during the positive half-wave of the mains voltage. In the case of a minus signal, they become positive during the negative half-wave. In addition to the 50 Hz alternating voltages excited in the resonant circuit 50 by the occurrence of a signal, there is also a permanent negative bias voltage. The bias voltage is chosen so that, as with the neutral triode 45, the plus and minus triodes also work in the lower part of the anode current-anode voltage characteristic. An anode current can only flow if the signal strength exceeds a selectable limit value.The anode of the plus triode is connected to the associated winding of the saturated transformer 54 in such a way that a positive voltage peak at the anode around the time of the peak value of the positive half-wave of the mains voltage occurs. During a plus signal, the grid alternating voltage of the plus triode is also in the positive phase at this time, so that a brief current surge occurs in the anode circuit. In the following negative half-wave of the mains voltage, there is no signal wave, but the neutral oscillating circuit continues to oscillate. In this case, however, the negative phase of the alternating grid voltage coincides with the negative peak of the anode voltage at the plus, triode. With the plus signal, current surges in the anode circuit of the plus triode only occur during the positive half-wave, that is, with the mains frequency. For the minus signal, on the other hand, the grid voltage is 180 ° out of phase with the plus signal. The positive phase of the grid voltage then coincides with the negative peak of the anode voltage and the negative phase of the grid voltage with the positive peak of the anode voltage at the plus triode. The resonant circuit 75 in series with the plus triode is therefore excited in its natural frequency with the plus signal, but not with the minus signal. The opposite applies to the minus triode, whose associated oscillating circuit 62 is only excited when the minus signal is received.Thus, the receiving relay coupled to the plus oscillating circuit only speaks with the plus signal and the receiving relay coupled to the Minue # oscillating circuit only with the minus signal at. The signal receiver according to FIG. 4 works correctly when the choke coil 56 is connected to the same phase conductor as the signal transmitter 14. So that the matched signal receiver 24 according to FIG. 4 also receives signals and differentiates between plus and minus signals If they come from signal transmitters 14 that are connected to any of the three phase conductors 2, 3 or 4, parts 45 to 80 must be carried out three times: The additional ones required for the two further phases, but not shown in the drawing Parts are designated in the following with the corresponding numbers according to FIG. 4 with the addition of index marks; For example, the three Relass for receiving the minus signals from the three phases are given the designations 70, 70 'and 7011. The three-fold design of the receiver circuit offers the possibility of differentiating the received signals into three groups of signal transmitters. Be advantageous when using the subject matter of the invention for remote transmission of meter readings, because this allows three telecontrol channels, namely the three phases of the network, to be used side by side for each network district, which makes it much easier to identify the individual signal transmitters from the receiving location. ben: If this option is not used, although the receiver circuit, as just mentioned, is designed in triplicate, the contacts of the relays 70, 70 'and 7019 can simply be parallel. The same then applies to the contacts of relays 80, 80 'and 8011 for the plus signal. In the case of the signal receivers 24 according to FIGS. 1 and 3, this possibility of differentiating the signals according to phases does not exist. On the other hand, no additional effort is required on these signal receivers if the various signal transmitters are distributed over the three phases of the three-phase low-voltage network.

In three-phase three-wire networks, i.e. three-phase networks without a neutral conductor, as is still in use in some places, the signal transmitter is connected between two phase conductors. If the signal generators are distributed over all three phases, three coupling transformers 26, 26 'and 26 ″, namely one each in the three phase conductors 2, 3 and 4, must be installed for the connection of the signal receiver according to FIG three unsaturated choke coils 56, 561 and 5611 and the primary windings 55, 55 'and 5511 connected in series with them of the saturated transformers 54, 54' and 5411 also connected to the phase conductors 2 and 3, 3 and 4, 4 and 2. If between If a distinction is to be made between plus and minus signals, the signaling devices must be connected in the same phase sequence.

In single-phase AC networks there is only a single coupling transformer 26 required. The signal transmitter and the signal receiver can analogously according to 1, 3 or 4 are built and connected. The above Explanations of the invention were based on an application in energy distribution networks laid, in which the mains alternating voltage has a frequency of 50 Hz. In Networks with a different frequency apply accordingly to the examples discussed other numerical values.

Instead of the circuit elements shown in the figures, of course equivalent electronic, electro-optical or electromechanical means, preferably Semiconductor components, are used, the circuit arrangement in principle at the same effect is to be met according to the respective components. As essential For the purposes of the invention, the principle of suppression described applies inter alia of interference waves outside the short time interval of each mains voltage half-wave in which a signal wave can arrive, furthermore the principle of tuning the timing of the signal wave sequence and finally the separation of the plus and minus signals using AC powered amplification means.

Instead of dampened charging oscillations like those provided by the signal generators 14 are generated according to FIGS. 1 and 4, would basically also mere charging current surges lead to the same goal. Such could be achieved by opening the changeover contact 18 at the end of the first charge current surge or by means of controlled electronic valves be generated. The course over time and the amplitude of the first half-wave of the Signal oscillation, which is decisive for the effect on the signal receiver, would remain unchanged, even if the Remainder of the charging oscillation on the signal transmitter would be cut off. Such variants are also conceivable, but require one somewhat gröl-Seren circuit effort on the signal generator 14.

The means described above for suppressing interference voltages are arranged exclusively in the signal receiver 24 and must therefore for a larger number of signal generators 14 only be present once. Of course However, it is possible to send the signals in the individual signal generators 14 in the manner of a To encode the pulse telegram, that means here, with the same information content to equip it with more redundancy. Suitable coding devices are for this. in different Forms known. The control contact 22 of the signal generator 14 would then be in the circuit a coding device arranged, which in turn of a transmission of the Signal-issuing device, e.g. controlled by a signal-emitting consumption meter would. In this way, it is true that the required for the individual signal generator Effort greater; However, it can do this even in networks with above average high continuous current level any degree of transmission security can be achieved. The circuit of the signal receiver 24 naturally contains a corresponding one in this case - also known - decoding device.

In the following there are still some considerations and suggestions for a signal transmission from the low-voltage network 1 to the medium-voltage network 12 is given. It has already been mentioned that the signal voltage and therefore the signal power in the medium-voltage network 12 is less than in the low-voltage network 1, if the signal generator 14 in the low voltage: network is located. If that from the signal generator The signal delivered to the low-voltage network is strong enough, so guaranteed also a coupling of the signal receiver to the medium-voltage network 12 a. impeccable Reception.

The signal current strength can, however, in particular by large, triangular connections capacitor banks connected to the low voltage network 1, e.g. Phase shift capacitors, be greatly diminished. Such a capacitor bank causes the signaling device 14 signal oscillations generated in one phase of the low-voltage network, e.g. in phase conductor 4 also scatter over into the other phase conductors of this network. In the low voltage winding 7 of the network transformer 6 (Fig. 1) then flows in almost in all three phases equally large signal current corresponding to lower strength in the same direction. Consequently is only one in the corresponding phase conductor, e.g. 11, of the medium-voltage network 12 very small signal current flow, the low-voltage transformers, which are usually equipped with three legs are namely not very suitable for the transmission of homopolar currents. Signal currents, which is nevertheless transferred from the low-voltage winding 7 to the medium-voltage winding 8 are transmitted, also have one in the three phases of the medium-voltage winding same direction and are approximately the same size, Through the These remaining signal currents are the usual delta connection of the medium-voltage winding mostly short-circuited. Via the corresponding phase conductor of the medium-voltage network therefore only a differential current flows, which is created by the fact that the in a phase conductor of the low-voltage network 1 generated signal current through a possibly existing capacitor bank not completely evenly on all three Phase conductor 2 to 4 is distributed, in this case is vain reinforcement or reshaping of the signal when it is transferred from the low-voltage side to the medium-voltage side recommend. The additional effort for this is relatively low, because for many signal transmitters only a single amplifier needs to be arranged. Hei application of series coupling no great effort is required here either. Just need the signal stream Sufficiently large and distinguishable from the mains current to ensure reliable separation from the mains, the signal voltage, on the other hand, can be very low.

To achieve signal amplification, it is basically possible a signal transmitter similar to that in the low-voltage network on the medium-voltage side of the transformer 6 to be arranged and this through one of the signal receivers described 24 control. However, encoder contacts for medium voltage cause difficulties. But you can also use a signal generator according to FIG. 1 or 4 on the low-voltage side connect between the mains transformer 6 and the coupling transformer 26 and with the secondary winding of a normal current transformer whose Primary winding installed in the corresponding phase conductor of the medium-voltage network 12 is to connect in series. Because of the leakage inductance of the current transformer, as well as the greater leakage inductance of the network transformer in relation to the medium-voltage side, and because of the greater length of the phase conductors 9, 10, 11, the signal frequency is with the same capacitance of the transmitter capacitor 15 in this case significantly lower than the signal frequency in the low voltage network. On the other hand is the signal frequency also not variable, so that a band filter can be used at the recipient location. There are two different frequencies to distinguish between the plus and minus signals and thus two band filters are required. The two different frequencies will be by different capacitance values of the transmitter capacitor for the two Signals causes. A normal current transformer can be used as a coupling transformer at the receiver location to serve.

These two at the transmitter location and at the receiver location in a phase conductor (e.g. 11) of the medium-voltage network 12 must have built-in current transformers without an air gap with a normal load calculated for the mains frequency in parallel with the signal transmitter 14 or signal receiver 24 are completed. The burden can be with one on the Mains frequency tuned series resonant circuit to be connected in series to it for to lock the signal frequency. If one also locks the giver and the Receiver circuit in relation to the mains frequency by means of a parallel resonance circuit, in this way, existing current transformers can also be used for other purposes. Instead of of decaying charging oscillations such as in the low-voltage network, can be passed on 'of the signals via newspapers of a higher voltage level also a normal one, that means undamped alternating current with a frequency deviating from the mains frequency be used. For example, frequencies such as 25, 100, 200 Hz are possible, which can be produced by frequency division or frequency multiplication and which stand out well from the harmonic noise level. Instead of a signal generator after the Pig. 1 for forwarding the signals to a network section of the next higher voltage level then occurs a frequency divider controlled by the signal receiver according to FIGS. 1, 3 or 4, Frequency multiplier or oscillator as a signal converter, or two instead a signal generator according to FIG. 4 for the delivery of two different signals a with different frequency. All other parts remain the same as when used of charging oscillations.

Claims (2)

P A, T E N T A N S P R U E C H E 1. Device for the transmission of Signals via a Vlechselstrom power distribution network by superimposing the network alternating voltage with an alternating signal voltage, the frequency of which is a multiple of the frequency of the AC voltage is and that by connecting a transmitter capacitor the alternating current network is generated in the cycle of the single or double network frequency, consisting of at least one signal transmitter and one signal receiver, characterized in that, that a high-pass filter (27) is arranged on the input side in the signal receiver (24), its cutoff frequency is at most equal to the lowest possible frequency of the signal alternating voltage is, and that the frequency of the signal alternating voltage generated by the signal generator (14) any values depending on the local Inge of the signal generator (14) in the network. above this limit frequency has. 2. Device according to claim 1, characterized in that the signal receiver (24) has a receiving relay (32) which is connected downstream of the high-pass filter (27). 3. Device according to claims 1 and 2, characterized in that the receiving relay (32) is a direct current relay which is connected electrically in parallel with a smoothing capacitor (31) to the high-pass filter (27) via a rectifier (30). 4. Device according to claim 1, characterized in that the input (25) of the signal receiver (24) is coupled to the network (1) via a coupling transformer (26). 5. Device according to claims 1 and 4, characterized in that the coupling transformer (26) corresponds in structure to a current transformer and has an air gap in the iron core. 6. Device according to claims 1 and 4, characterized in that the coupling transformer (26) is a normal current transformer, on whose secondary winding electrically parallel to the input (25) of the signal receiver (24) there is a hurdle via a low-pass filter whose cutoff frequency is at most equal to Cut-off frequency of the high-pass filter (27). 7. Device according to claims 1 and 6, characterized in that the current transformer is a conversion converter. B. Device according to claims 1 and 4, characterized in that the signal receiver (24) is connected in series with the network (1). 9. Device according to claims 1 and 4, characterized in that the signal receiver (24) is connected in parallel to the network (1). 10. Device according to claim 1, characterized in that the signal receiver (24) is arranged in the same, galvanically connected network section as the signal transmitter (14). 11. Device according to claims 1 to 10, characterized in that the signal receiver (24) is coupled to the same phase conductor (4) as the signal transmitter (14). 12. Device according to claims 1 to 11, characterized in that a. Working contact (33) of the receiving relay (32) is arranged in the circuit of an evaluation part (38). 13. Device according to claims 1 to 12, characterized in that at least one further normally open contact (34 or 35) of at least one delay relay (36 or 37) is connected in series with the normally open contact (33) of the receiving relay (32). 14. Device according to claims 1 to 13, characterized in that an electrical threshold is arranged in the excitation circuit of the receiving relay (32). 15. Device according to claims 1 and 14, characterized in that the electrical threshold is then a Zener diode (39). 16, device according to claims 1 and 14, characterized in that the electrical threshold is then a power gate that can be adapted. 17. Device according to claims 1 and 16, characterized in that the controllable current gate is an amplifier element. 18. Device according to claims 1 and 16, characterized in that the controllable current gate is an electromechanical relay. 19. Device according to claims 1, 16 and 17, characterized in that the controllable current gate is a contactless circuit element, for example a triode (45). 20. Device according to claims 1, 16 and 17, characterized in that the controllable current gate is an electro-optical component. 21. Device according to claims 1 to 20, characterized in that the signals are generated in or near the peaks of the mains voltage. 22. Device according to claims 1 and 21, characterized in that the signals are generated in or near homologous peak values of the mains voltage. 23. Device according to claims 1 to 21, characterized in that the working voltage of the amplifying current gate (45) is taken via a rectifier (57) of a partial winding (53) of a transformer (54) with a saturated iron core, the primary winding (55) of which in series with an unsaturated choke coil (56) with an air gap on the same conductors (4,., 5) of the network (1) as the signal transmitter (14). 24. Device according to claims 1 and 23, characterized in that the receiving relay (32) is fed from the working circuit of the current gate (45. 25. Device according to claims 1 and 23, characterized in that in the working circuit of the current gate (45) on the 26. Device according to claims 1 and 25, characterized in that the receiving relay (32) is inductively coupled to the resonant circuit (50), possibly with the interposition of a rectifier with smoothing means according to claims 1 and 23, characterized in that the current gate (45) designed as an amplifier element is operated with the aid of a bias voltage source (49) in the initial region of its characteristic curve. 28. Device according to claims 1 to 23, characterized in that the resonant circuit (50 ) two controllable current gates (58, 72) are inductively coupled, whose working circuits each have a further one on the mains frequencies z matched resonant circuit (62, 75) and are fed in phase opposition from windings (67, 74) of the saturated transformer (54). 29. Device according to claims 1 and 28, characterized in that a DC relay (70, 80) is inductively coupled to each of the two further oscillating circuits (62, 75) via a rectifier (68, 78) each with smoothing means. 30. Device according to claims 1 to 29, characterized in that all rectifiers are full-wave rectifiers, preferably arranged in a bridge circuit. 31. Device according to claims 1 to 30, characterized in that in the signal receiver (24) for receiving and distinguishing between signals arriving on different phase conductors of the network (1) according to phase and polarity, at least all except the high-pass filter (27) and the downstream one Rectifier (30) existing parts for each phase conductor (2, 3, 4) of the network (1) are arranged once. 32. Device according to claims 1 to 31, characterized in that the signal transmitter (14) consists essentially of a resonance oscillator or a polarized relay (16) with a switch contact having a contact tongue (19) and two counter contacts (20, 21) (18) and consists of a transmitter capacitor (15) electrically connected in series with the Umsohaltkontakt (18), 33. Device according to claims 1 and 32, characterized in that the winding (17) of the relay (16) with an active or Impedance resistor (23) is connected in series. 34. Device according to claims 1 and 32, characterized in that a control contact (22) is connected in series with the mains connection of the signal generator (14), 35. Device according to claims 1 and 32, characterized in that the mating contacts (20 , 21) are connected electrically in parallel. 36. Device according to Claims 1 and 32, characterized in that one of the mating contacts (21) is connected to a discharge resistor (44) arranged electrically parallel to the transmitter capacitor (15). is. 37. Device according to claims 1 and 32, characterized in that one winding end of the winding (17) of the polarized relay (16) is connected to the division point of a voltage divider. 38, device according to claims 1 and 37, characterized in that the voltage divider consists of real or apparent resistors (23, 40). 39. Device according to claims 1, 32 and 37, characterized in that a. Winding end of the winding (17) of the relay (16) is connected to the switching arm of a selector switch (41) whose selector contacts (42, 43) are electrically parallel to the voltage divider (23, 40). are switched. 40. Device according to Claims 1 and 32, characterized in that an auxiliary capacitor is connected in parallel to the winding (17) of the relay. 41. Device according to Claims 1, 34, 35 and 40, characterized in that the selector switch (41) is in a neutral central position and serves as a control contact. 42. Device according to claims 1, 34 and 41, characterized in that the control contact is in operative connection with a signal-emitting consumption meter. 43. Device according to claims 1 to 42, characterized in that the signal receiver (24) and the signal transmitter (14) are arranged in inductively coupled network sections (1, 12). 44. Device according to claims 1 and 43, characterized in that for amplifying and / or transforming the signal before it is forwarded in a medium-voltage network (12) which is connected to the low-voltage network (1) by a transformer (6), in which there is the signal transmitter (14) is located, an amplifier is arranged. 45. Device according to claims 1 and 44, characterized in that the amplifier consists of a signal receiver (24) and a signal transmitter (14) connected downstream of this and controlled by it. 46. Device according to Claims 1 and 45, characterized in that the signal transmitter (14) is connected to the medium-voltage network (12) via a current transformer. 47. Device according to claims 1 and 44, characterized in that the signal receiver (24) is connected to the medium-voltage network (12) via a current transformer. 48. Device according to claims 1, 46 and 47, characterized in that the current transformers are each closed with a hurdle that is connected in series with a series resonant circuit tuned to the mains frequency. 49. Device according to claims 1, 46 and 47, characterized in that the signal receiver (24) and the signal transmitter (14) are blocked from the mains frequency by a parallel resonance circuit tuned to the signal frequency. 50. Device according to claims 1 and 44, characterized in that the signal is fed into the medium-voltage network in the form of an undamped alternating current. 51. Device according to claims 1 and 50, characterized in that the undamped alternating current is generated by dividing or multiplying the network frequency. 52. Device according to claims 1 and 45, characterized in that two transmitter capacitors of different capacities are arranged in the signal transmitter (14). 53. Device according to claims 1 to 52, characterized in that the signal transmitter (14) is assigned a coding device and the signal receiver (24) is assigned a corresponding decoding device.