Verfahren und vorrichtung zur erkennung und ortung von hochohmigen einpoligen erdfehlern

The invention describes a procedure for the selective recognition and detection of high impedance single-pole Erdfehlern in neutral point-compensated electrical supply networks, with which into the Nullsystem of the net at least a Hilfssignal with the frequency OJN is fed, as well as a mechanism consisting of a signal generator for production at least a Hilfssignals with the frequency o N and a rule unit for recognizing and locating single-pole Erdfehlern to would drive out the procedure. The invention places itself the task to create a procedure and an associated device of the kind initially specified with that it is possible, very high impedance, to recognize and locate single-pole Erdfehler surely and reliably. The task is solved for the procedure by the fact that the Hilfssignal is fed in such a way that by it the neutral point misalignment tension Un “(OJN) is thus compensated with frequency WN, the tension between the neutral point of the food transformer of the net and/or the bulk eraser and the earth, essentially and that Erdfehler are recognized and located with by the Hilfssignal of compensated neutral point misalignment tension Une (OJN). For the device the task placed above is solved by the fact that an element of the net, for example the bulk eraser, is subjectable preferably a plunger coil, with this Hilfssignal and that the signal generator is intended by means of the produced Hilfssignals for the compensation of the neutral point misalignment tension Une (OJN). With the procedure according to invention for the first time the StempunktVerlagerungsspannung is compensated concerning the net-frequent portion for the recognition and detection from Erdfehlern to zero, with which in the Nullsystem actually the neutral point misalignment tension not desired in supply networks disappears. Beyond that also very high impedance Erdfehler with very simple means, very selectively and reliably by this compensation, can be located since in the case neutral point misalignment tension compensated by high impedance single-pole Erdfehlern during the fault current which can be located is increased at the same time and the selectivity and security of the detection is thus improved. For the Betdeb of an electrical supply network it is to be had very favourably no StempunktVerlagerungsspannung Une (OJN) with frequency. This is reached according to invention, as for example the Hilfssignal fed in form of a river is in such a way steered with frequency i (OJN) by a rule unit in amount and phase that the sum of this fed Hilfssignal and the natural misalignment stream, thus the sum of the unbalance stream of all branches or line sections of the net, becomes essentially identically zero. By a such feed of such Hilfssignales one reaches a compensation of the neutral point misalignment tension Uù (OJN) by the compensation of the unbalance stream of the total net in consequence naturally. This becomes concerning the frequency portions thus zero. For the procedure it is very favourable that by fairs of of the fed river with frequency ivC (OJN) in in-regular condition, thus with ivc (O N)+ivS (OJN) =O indirectly the natural is measured misalignment stream ivS (OJN), thus the sum of the unbalance stream of all branches or line sections of the net, and the fact that with this measured river ivc (O N) a Erdfehler in the total net is recognized. Thus a Erdfehler can be recognized and indicated, if the measured value of the river with frequency i C (OJN), which can be fed, preferably the amplitude, which amount or the rms rises, strongly and crosses a pre-defined error threshold. Alternatively to it a Erdfehler can be recognized and indicated, if the amount 4s of the complex difference of two temporally following each other measurements of the river which can be fed with frequency ivC (OJN) (in each case in in-regular condition) strongly rises and a pre-defined error threshold exceeds. Both possibilities can be converted and offered with very simple means a very reliable recognition of Erdfehlern. Thus also very simply the incorrect can be found branch or line section of the net, there by fairs of zeroing Rome iö) (OJN) in to in-regular condition, thus with Uù (WN) =O, by each branch or line section of the k of the net with frequency O) N directly the sum of the natural misalignment stream i (vk) in further consequence (oJN) and a possibly existing fault current of the respective k-ten branch or line section with frequency one measures and these zero-stream iö) (WN) for the determination of the incorrect branch or line section of the net and/or the incorrect place within this branch 2 RKs 411,937 B or line section to be consulted to be able. A very simple procedure results, if for (best for everyone) a branch or a line section f zugehönge zeroing Rome i (f) (WN o,), preferably the amplitude, which amount or the rms is compared, with a pre-defined error threshold and recognized and indicated as incorrect, if the amount of the complex zeroing Rome vector iö) (O) N) this error threshold for a pre-defined time exceeds. A possible alternative results, if for (best for everyone) a branch or a line section f of two temporally following each other measurements of the associated of zeroing Rome J (f) (WN) (in each case in in-regular condition) the complex difference is formed, the amount of this difference is compared with a pre-defined error threshold and an incorrect branch or line section is recognized and indicated, if the amount of the difference crosses this error threshold. One receives thus in sum and a little complex procedure for the recognition and detection, which can be implemented very simply, from also very hochhohmigen Erdfehlem, which can be operated additionally still with a very high Seleklivität. If the misalignment stream (unbalance stream) of the total net, indirectly thus the fault current, rises so strongly the fact that it cannot be compensated by the fed river no more is completely particularly favourable it, if one can switch to another more suitable procedure for the detection of Erdfehlern, since then the fault location remains further ensured. Completely particularly simply and in favourable way Iässt the procedure according to invention for the recognition and detection of high impedance Erdfehlern with a procedure for the vote of a bulk eraser are connected, by at least a further Hilfssignal with a frequency w unequally the frequency o) N one feeds and this Hilfssignal for the vote of the bulk eraser one uses. Thus the bulk eraser can be recognized co-ordinated with the net continuously, can thus switching actions in the net and be guaranteed additionally still the recognition and detection by Erdfehlem despite compensated neutral point Vedagerungsspannung with frequency. For the vote of the bulk eraser it is particularly favorably, that for example in form of an electric current fed Hilfssignal i; -. (w1) and the neutral point misalignment tension Une (o), developing from it, 1) concerning a frequency 0 1, unequally the frequency 0 N, bei6dN 36dN spielsweise o 1 = or 0) 1 = to measure continuously after amount and phase and 2 2 by quotient formation of i -. (oJ) and Une (w) the admittance sum to determine from the earth admittance of all branches or line sections of the net Ys (oJ1) and the bulk eraser admittance YL (oJ) and to determine from this in further consequence the net parameters sum capacity Cs and the conductance sum of the sum conductance gs of the total net and dern coil conductance gL the bulk eraser. Alternatively to it these net parameters can be determined also from the measured values with several frequencies wj, unequally the frequency o v, whereby from the quantity of the individual frequency portions of the measured values by an optimum approximation in the sense of the minimization of an error function the best-approximating net parameters are determined. Thus one is for the first time able, without being able to determine an adjusting of the bulk eraser and also without change of the natural or artificial unbalance current portion in the Nullsystem all for the vote of the bulk eraser necessary net parameter continuously and in very simple way. It is completely particularly favourable to unequally select the sizes of the Hilfssignale with a frequency in such a way wj the frequency w v that the rms of the neutral point misalignment tension resulting from it Une (wj) becomes with this frequency comparatively small, preferably smaller 10% of the rms of the primary wave of the phase rated voltage of the net, since then these small overlays of the mains voltage are negligible in the Nullsystem. The procedure becomes completely particularly selective and exactly, if the frequencies are selected in such a way oJj that the primary wave portions and also the harmonic wave portions of the frequency spectra of all fed signals do not overlap with the primary wave rotative frequencies o) and ON, since then each feeding signal for itself may not be regarded alone and itself overlays of signals with different primary wave frequency concerning their reason - or Oberwellenspeldren result in 411,937 B in connection with the Fourierreihenzerlegung or Foudertransformation RK. Thus it is particularly guaranteed that the frequency portions used for the resonance vote, and/or net parameter determination in no integral odd-number relationship with the frequency and be excluded with the fact it can stand that the natural unbalances of the net in the form of unbalance stream the voting result, and/or which can affect result of the net parameter determination. With the well-known net parameters the bulk eraser for the net can be co-ordinated with frequency wN. This can be accomplished, as with the sum capacity Cs of the total net is determined the point of resonance with frequency wN, and which is determined and adjusted inductance L of the bulk eraser according to the resonance relationship, so that gelo wished compensated, under-compensated or vote of the net overcompensated is reached. Alternatively to it the inductance of the bulk eraser can be so for a long time adjusted with a rule unit, until the desired compensated, under-lowest or overcompensated vote of the bulk eraser is reached. Further favourable result of the procedure according to invention is it that from the determined net parameters specific characteristics, as for example the coil stream iu s, are computed and indicated thus the bulk eraser stream in resonance with frequency and neutral point misalignment tension Uùe equal the phase rated voltage, or the Watt residual current iw the net. Such characteristics serve the specialist for the evaluation of the total condition of the net and are in connection with the isolation condition important notes to the quality of the net. One receives very favorable executable procedure, if the Hilfssignale concerning all fed frequencies w; and N by a signal generator to be produced. This Iässt simply would drive through themselves, by the Hilfssignale by a low-pass filtering of a square wave signal, which by overlay of square wave signals of the individual frequencies of all frequency portions); and (- N is formed, to be produced. In very simple way the square wave signal in the signal generator by opening and reasoning of switches $1, $2, $3 and $4, is preferably produced for transistors in the branches of a H-bridge by a heading for unit and the square wave signal in the diagonal of the H-bridge is measured. The Tiefpassfllterung of the square wave signal takes place if necessary most simply in a low-pass filter consisting of an inductance Lc and possibly a capacity CC, which is dimensioned in such a way that from the square wave signal produced in the H-bridge all frequency portions are filtered more largely a pre-defined corner frequency from the Hilfssignal which can be fed. In this way the composite signal of the Hilfssignales which can be fed can be produced through to a large extent 3s decoupled overlay of the individual signal portions with different primary wave frequency in amount and phase. For the security of the device it is favorable, if an overvoltage protection is intended, with which the achievement split field of the bulk eraser in case of a Erdfehlers and/or if the misalignment stream exceeds ivs (OJN) a maximally permissible value, by a switch $5 from the circuit to the generation of the Hilfssignale is separable. One receives a completely particularly flexible, favorable and simple execution form, if as rule unit and/or heading for unit a microcomputer is intended. The invention becomes on the basis the following explanations with reference to the accompanying exemplary and schematic designs Fig. 1 to Fig. 3 more near beschneben. In the designs Fig shows. 1 the electrical alternate circuit diagram of the Nullsystems and a branch of a stempunktkompensierten net, Fig. 2 an exemplary, schematic diagram for the production of the Hilfssignale and for the evaluation of the net condition, Fig. 3 two different frequencies, w and, - - containing, overlaid square wave signal. In Fig. 1 is represented the well-known electrical alternate circuit diagram of a line section of a high-voltage transmission system. Between the transformer neutral point and the point of grounding is a bulk eraser 9, which is described by a Ohm's conductance gL and an inductance L 5s. Strewing inductances as well as Ohm's resistances of the secondary winding RK 411,937 B of the food transformer are represented by for all three phases as equally large accepted line longitudinal impedances the ZLT. Consisting into the net, here of only one line section, the phase voltages U1, /-/2 and U3 are fed and it flow the phase stream i1, /2 and /3. Between the three phases and the earth the phase earth tensions U1 E, U and U3 E lie close. A line section becomes, as &lt for the regarded frequency range of; 100Hz permissible, by line longitudinal impedances Z, consisting of a Ohm's and an inductive term, and Leitungsableitadmittanzen YA1, YA2 and YA3, consisting of a Ohm's and a capacitive term, described. Over the Leitungsableitadmittanzen YA1, YA2 and YA3 flow the derivative stream iA1, iA2 and iA3. The derivative stream iA1, iAZ and iA3 flow back as zeroing Rome IO of this line section over the bulk eraser 9 to the Transformatorstempunkt. At the point of grounding of the bulk eraser 9 the zero-stream of all unite available line sections to the sum of the zero-stream loosely. Consumer-laterally, represented by Verbrauchedmpedanzen Zv, flow the loads iw, iw and iv” this alternate circuit diagram for the derivation from relations important for the erflndungsgemäße procedure one uses. To the following explanations it is marked first that itself the following formulas, if not differently marked, to the Laplacetransformierten of the respective electrical sizes refers, which are not written to occurring electrical sizes for simplification of the way of writing however explicitly than function of the complex frequency variable s, therefore becomes for example us (S) with us designated. As from the electrical alternate circuit diagram Fig. 1 to be taken knows, arises zeroing Romes I'o of any branch as very good approximation from the relationship %= U, “” Y+iv, with the earth admittance Y = (YAI + YAZ + YA3) and the misalignment stream, and/or unbalance stream, iv = (UI ", 4 YA + U2 “It YA2 + U3 “A YA3), whereby/tYA describe the unbalance of the Erdadmittanzen. For the earth admittance Y of a branch k it is sufficient in the regarded frequency range (< to represent 100Hz) in sufficient accuracy Y by the sum of the individual phase earth capacities C parallel to the sum of the Ohm's conductance of the three phases against earth g. k) = g (k) ÷ C (k; s for the sum of the zero-stream of all branches ios is valid then for the eartherror free total net loosely = Uù ““Ys + ivS, whereby Ys designates the sum of the Erdadmittanzen of all branches and ivs the sum of the misalignment stream of all branches or line sections. In accordance with the relationship for the earth admittance Y of a branch Cs of all branches Ys= gs follows + Css by accumulation, with the sum conductance gs of all branches and the sum capacity. The zero-stream of all branches flow back loosely thereby over the bulk eraser to the Transformatorstempunkt, whereby the following relationship can be set up. ios = - Uù “. YL YL is the admittance of the point of grounding of the bulk eraser up to the transformer neutral point and consists of a conductance gL and inductance L. =gL + L.s RK 411,937 B I0 by equating the above equations for sum zeroing Rome i0 s one receives a relationship between the misalignment current sum to 1 YL ivs and the neutral point misalignment tension Une. ivs = - Uù ““(to Y + YJ replaces one in the above relationship now the complex Frequenzvadable s through joJ, with the rotative frequency OJN = 2rrfN and the frequency fN, arises the following equation ivsfWN) =-UùJoJN) '[Ys (w) + YdoJN)], 1 with Ys (OJN) = gs +] oJNCs and YL (OJ = gL + jco” L” by active bringing in of a river i C (W) into the neutral point, for example by current feed into the achievement split field of the bulk eraser, directly i s (coN) follows + i from the Überlagerungssatz (o = - UùJw. [Ys () + YdoJ l. From this equation one receives the important realization that the neutral point Vedagerungsspannung Un “(WN) must be zero, if one the river ivc (OJN), which can be fed, after the relationship ivs (WN) + ivC (OJ = 0 i (N) = - i s () selects, there the term [Ys (OJN) +YL (WN)] only Netzgrößen contains and zero is surely not equal. That means that the neutral point misalignment tension UN (WN) is compensated, if IN SUCH A WAY the fed river i C (WN) is regulated that it follows the negative misalignment stream ivS (WN). Because the neutral point misalignment tension Une (WN) is regulated with frequency to zero, can be measured by measurement of the zero-stream iö) the individual branches or line sections k of the net directly the natural misalignment stream i (vk) including a possibly existing fault current of these branches or line sections, since the zeroing novel parts of the branch or line section caused by the Erdadmittanzen are missing because of the absence of a neutral point misalignment tension. These measured zero-stream i (ok) can be supplied then to any method for the detection by Erdfehlem. In the following exemplarily a possibility for the detection is described by Erdfehlern. In case of a single-pole Erdfehlers somewhere in the net increase those misalignment current sum i (OJN) suddenly strongly on. This rise can be detected very simply by Uberwachung of the river ivC (WN), which can be fed, there the rule condition i C (WN) = - ivs (OJN) and thus also the river i (WN), which can be fed, is valid rises obligatorily at the same time. if the amount of the river i C (OJN), which can be fed, crosses a certain pre-defined error threshold for a pre-defined time, a Erdfehler is recognized and indicated. Alternatively to it also the temporal change of the river i C (WN) in form of the amount of a complex current difference, on an excess of an error threshold, which can be fed, can be supervised for the recognition of a Erdfehlers. , is the defective branch or line section can be located by measurement of the frequency portion of zeroing Rome of the i (ok) in amount and phase, to which during a neutral point misalignment tension Uùe (WN), regulated to zero, corresponds to the sum of the natural misalignment stream i (vk) and a possibly existing fault current of this branch or line section. A simple method is, the amounts, to supervise rms or amplitudes of the zero-stream i (ok) with frequency of all supervising branches or line sections k on a possible excess of a pre-defined error threshold for a pre-defined time. Another method is, the amounts and/or the rms of the temporal change of the zero-stream with frequency of all supervising branches or Le! tungsabschnitte k, thus the amounts of complex computed zeroing Rome differences to supervise on a Uberschreitung of an error threshold. RK 411,937 B I0 however is also every other arbitrary well-known method possible for the detection of the defective branch or line section and/or the defective place within the defective branch or line. This procedure is naturally only so long applicably, as long as the signal generator is able, the net-frequent neutral point misalignment tension to regulate by feeding an appropriate river to zero. To be switched will this border überschdtten is it meaningfully to another procedure for the detection of Erdfehlern, until the river which can be fed can be applied by the signal generator again. In order also during compensated neutral point misalignment tension would drive through, becomes the vote of the bulk eraser to be able at least a further river ivc (W), with oJ; ¢ wN fed into the neutral point and it results under the condition that the frequency spectra of the individual frequencies do not cover themselves and/or overlays and so that no natural misalignment stream of the net with this frequency oJ WN are present i s (o i)=O. equivalent to above the equation ivc (OJ) = - UùJ J. [Ys (oJ” + YL (o J], with Ys (Wi) = gs +jwiCs and YL (Wi) = gL + -- 1 jwiL, from which because of the fame of bulk eraser inductance L from the current position of the bulk eraser by inserting L into the above equations the conductance sum (gs +gL) and the sum capacity Cs of the net, thus the desired net parameters, can be determined. U, ù, (s) = [Ys () +Y, (e))] = (gs +g,) + (e Cs - from this follows directly (gs + gJ = RH [Ys (Wi) + YL (w)] and Cs = - T {in [Ys (o),) + Y, (o)] + -- L} by continuous measuring of of the fed river ivc (W) amount and phase during rotative frequency (wj) and itself the resulting in the neutral point misalignment tension Une (W) in the case of it with a frequency unequally the frequency, (wi) (WN), after amount and phase can be directly continuously computed thus from the above equations the Netz_parameter. These net parameters can also for several different frequencies (w) # (WN) to be determined and anschlieBend from the individual sizes of an average value in the sense of the optimum approximation of the material sizes be intended. The resonance vote of the bulk eraser takes place then with net frequency (OJN) on the basis the well-known resonance condition 1 in [Ys (WN) + YL (O N)] = 0 WNCs ojNL from this equation knows necessary bulk eraser inductance L for reaching that the desired compensated, more überoder under-compensated vote to be determined, on which the bulk eraser can be co-ordinated directly. The procedure for the vote of the bulk eraser, described above, is not restrictive, it is rather also all other possible procedures as well as combinations of certain procedures applicable. E.G. it is conceivable to change the inductance of the bulk eraser in an automatic control loop until the point of resonance is reached or an appropriate more überoder under-compensated position results. The generation of the Hilfssignale which can be fed and the evaluation of the measured RK 411,937 B sizes become exemplary on the basis the Fig. 2 described. The circuit for the generation of the Hilfssignale contains an electric rectifier unit 1, a signal generator of 2 with a Tiefpassfllter downstream 3, a rule unit as well as an overvoltage protection 5. the electric rectifier unit 1 contained beside a wetting running transformer, which uses full-wave rectification and the filter capacitors a power Factor Correction (PFC) circuit and as supply voltage for example the conventional mains voltage, thus 230V, 50Hz. The PFC circuit ensures that by mains supply only pure active power is taken up, whereby a very low capacity of the overall system results and offers at the exit for the further use DC voltage of 400V. Depending upon execution of the PFC circuit and according to RST need also another DC tension can be supplied. The PFC circuit feeds a signal generator 2, which contains a H-bridge 6, in their branches per a switch $1, S2, $3 and $4, preferably transistors, is arranged. The switches $1, $2, $3 and $4 can be closed or opened over a heading for unit 7 independently. At the diagonal of the H-bridge 6 a signal is measured, which is filtered in a nachgeschaltenen from an inductance Lc and a capacity CC existing low-pass filter 3. The filtered signal is fed in this example over an achievement split field 8 of the bulk eraser 9 into the neutral point of the transformer. If the harmonic waves of the signal which can be fed should not disturb, then the capacity CC can also be void, since by the integrals are alone already formed the current behavior of inductance Lc out of tension rectangles of current trapezoids and thus the harmonic wave portion of the river which can be fed is already clearly reduced. As controlled variables the neutral point misalignment tension Uùe and the fed river ivc are measured kontinuiedich after amount and phase, for all interesting frequencies, and supplied to a rule unit 4, which makes again the heading for signals available for the heading for unit 7. The heading for unit 7 heads for the switches $1, $2, $3 and $4 in such a way that at the diagonals the H-bridge 6 from several existing overlaid square wave signal develops for individual square wave signals, which contains all frequencies which can be fed. A positive output signal of 400VDC is produced, if the switches $1 and S4 are through-steered and the switches $2 and $3 to remain open. Turned around an output signal of -400VDC develops at the bridge diagonal, if the switches $2 and $3 are through-steered and the switches $1 and $4 to remain open. If an output voltage is to be realized by 0VDC, then the switches $2 and $4 are through-steered and the two remaining switches are left open. Independently if no bridge diagonal stream is to flow of the neutral point misalignment tension, then all switches are $1, $2, to open $3 and $4. Such a square wave signal, that the frequency by 50Hz and a further frequency of 25Hz is contained in Fig. 3 represented. In particular at least the frequency must be contained N and a further frequency 0i with the procedure according to invention, whereby all frequencies are selected naturally in such a way wi WN that the primary wave portions and the harmonic wave portions of the individual frequency spectra do not overlap. Thus it is guaranteed that the individual frequency portions may be regarded independently and no Hilfssignal contains portions of another frequency. Favorably 30 is) N for example the frequencies = c°r' or oJ =. In such a way produced square wave signal is supplied to a low-pass filter 3 in 2 2 the connection, which is so dimensioned that if necessary higher frequency portions are filtered, whereby in accordance with the Fourierreihenzerlegung of the square wave signal only more the low-frequency portions of the individual frequencies which can be fed remain, whose amplitudes are separately controllable over the pulse duration width unit of the individual square wave signals and whose common phase relationship is likewise controllable. Meaningfully the amplitudes of the fed rivers of the frequencies are to be selected oJi wt in such a manner that the misalignment tensions resulting in the net from it accept the orders of magnitude of approximately 1% of the primary wave of the phase voltage, thus related to the phase voltage of the net small and thus as not net-frequent overlays become negligible. The amplitude of the signal with the frequency (ON) and the common phase relationship of the signals, are regulated accordingly by the rule unit due to the before indicated rule condition, i - (on) = - ivs (WN), ss. RK 411,937 B for the protection of the individual components with ground faults is further an overvoltage protection 5 intended, which separates the achievement split field 8 if necessary over the switch $5 from the circuit to the Hilfssignalgenederung. In the rule unit 4 the measured sizes are evaluated in accordance with the procedure for the vote of the bulk eraser g and/or for detecting of Erdfehlem, described above. The circuit described above is only one example like the Hilfssignale which can be fed to be produced can and is restrictive in no way. It is also conceivable in particular for each hoof signal its own signal generator, which generates an appropriate signal to use. Furthermore the possibility exists the Hilfssignale in form of an electrically isolated supply terminal in series connection to the bulk eraser of bringing over a galvanic separation in form of a current injection into one of the three phase earth tensions or in every other suitable way into the Nullsystem.