WO1992018872A1 - Process for detecting a branch circuit subject to earth leaks in an electric power supply or distribution system - Google Patents

Process for detecting a branch circuit subject to earth leaks in an electric power supply or distribution system Download PDF

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Publication number
WO1992018872A1
WO1992018872A1 PCT/AT1992/000053 AT9200053W WO9218872A1 WO 1992018872 A1 WO1992018872 A1 WO 1992018872A1 AT 9200053 W AT9200053 W AT 9200053W WO 9218872 A1 WO9218872 A1 WO 9218872A1
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WO
WIPO (PCT)
Prior art keywords
earth
branch
circuit
individual
zero
Prior art date
Application number
PCT/AT1992/000053
Other languages
German (de)
French (fr)
Inventor
Albert Leikermoser
Franz Kriechhammer
Original Assignee
Elektro-Bau Ag
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Filing date
Publication date
Application filed by Elektro-Bau Ag filed Critical Elektro-Bau Ag
Publication of WO1992018872A1 publication Critical patent/WO1992018872A1/en

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
    • G01R31/52—Testing for short-circuits, leakage current or ground faults

Definitions

  • the invention relates to a method for determining a branch circuit with earth faults in an electrical supply or distribution network, in which an earth fault quenching choke is connected between the network or transformer star point and earth, the difference between the for each individual circuit when the network operation is cleared the conductance values obtained before and after a change in the neutral point impedance are determined as quotients of the branch zero current and the displacement voltage in magnitude and phase, and the circuit in which this difference is at a maximum, that is to say approximately equal to zero, is rated as having a ground fault.
  • a method of this type has the separate earth fault directional and earth fault intermediate relays for the individual branch circuits, which has the advantage that it requires only a few measuring points, even with earth faults with only low displacement voltages due to high earth contact resistances fault location is possible.
  • the method is mainly used for radiation networks. For changes, the star point impedance occurs in healthy branching to no change in the above-mentioned conductance, whereas in erdschluß ⁇ affected branch of the conductance due to the discharge to earth e i n e change found, so that the difference of Leit ⁇ values before and after the change the neutral point impedance is not equal to zero.
  • the object of the invention is to provide a method which O 92/18872 PCT / ATO / OOOSS
  • the object is achieved in that a plunger choke coil is used as the quenching choke and the plunger core setting is changed between the measurements, the conductance values of the individual branch circuits being measured from measurements of the branch zero current as the sum of the phase currents flowing in the branch and the displacement voltage between The star point and earth are calculated taking into account the phase position between zero current and zero sequence voltage and are subtracted for each individual branch in a complex manner, and the branch where this difference is at a maximum is rated as having a ground fault.
  • a plunger choke coil has the advantage in itself that it can be set to or in the vicinity of a resonance point in the event of an earth fault in which an imaginary equivalent circuit diagram of a parallel resonance circuit consisting of coil inductance, the sum of the ohmic derivatives and the total capacitance resonates so to favor the earth fault cancellation.
  • simple measurement cables and a computer are sufficient to be able to carry out the necessary determinations without complex additional devices, in particular in the power section of the network or the choke coil.
  • the plunger choke coil will be set essentially to resonance in the first measurement and will be detuned from this setting by a predetermined amount for the second measurement cycle.
  • the method according to the invention can also be carried out if only the loading condition is fulfilled that the two measuring points correspond to different coil positions. It is possible to control the drive device of the plunger core choke coil for detuning the choke coil after the first measurement cycle and for resetting or adjusting the resonance point after the second measurement cycle, the resonance point in FIG Supplementing the described method can be determined by moving to a third plunger position.
  • Fig. 1 shows a measuring system which can be used to carry out the method according to the invention in a block diagram
  • Fig. 2 shows an equivalent circuit diagram for a branch circuit with an earth fault connected to the earth fault quenching choke to explain the method according to the invention.
  • FIG. 1 shows a schematic representation of an arrangement of devices for determining a branch with a ground fault in a radiation network.
  • the star point of the secondary side of a power transformer 1 is connected to a plunger choke coil 2, the plunger core of which can be adjusted with the aid of a drive device 3.
  • the displacement voltage present between the star point and earth at the choke coil 2 is detected and transformed via a voltage converter -4 and then adapted in a further converter stage with a bandpass filter 5 and freed from harmonics.
  • the effective value of the measured variable is determined in a signal processing unit 6 and subsequently brought into digital form with the aid of an A / D converter and passed on to a computer 12. 6 also becomes a measured variable in-phase square wave signal for digital further processing derived and output to the computer 12.
  • Signalmulti- plexer 9 switches the selectable via the computer 12 Null ⁇ current signal to a bandpass filter 10 where it is freed from harmonics and • a signal processing unit 11 is supplied, in the formed the effective value of the selected filtered residual current signal, and a A / D converter is brought into digital form. Also in the signal processing unit 11, a rectangular signal in phase with the measured variable is formed and, like the digital value of the effective value of the measured variable, is passed on to the computer 12.
  • the plunger core of the plunger core coil 2 is then adjusted via the drive device 3 in the sense of detuning, wherein this adjustment can also be controlled from the computer 12.
  • the master values determined in the first measuring cycle (before the moving core coil adjustment) are subtracted in a complex manner from the leading values determined in the second measuring cycle (after the moving core coil adjustment).
  • the branch in which the difference between the two leading values is at a maximum is recognized as having a ground fault and a corresponding storage is carried out for it. Now the whole process is repeated. If the same branch is identified again as having a ground fault, the result is displayed on a display unit 13. Otherwise, the measuring process is repeated until the same branch has been identified as having a ground fault in two successive measuring processes.
  • FIG. 2 is an equivalent circuit diagram for a branch circuit, for. B. 14A.
  • the plunger core coil 2 is located at the star point of the transformer 1.
  • the three phases of this branch circuit have phase voltages that can be measured with respect to earth.
  • g R, g s the conductances gm of the ohmic derivatives of the individual Pha ⁇ sen to earth and with C R, C ",, Cm denotes the capacitance of the individual phases to earth.
  • C R, C ",, Cm denotes the capacitance of the individual phases to earth.
  • this has a conductance g «with respect to earth. the earth fault resistance.
  • In the branch flows a z. B.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Measurement Of Resistance Or Impedance (AREA)
  • Testing Of Short-Circuits, Discontinuities, Leakage, Or Incorrect Line Connections (AREA)
  • Locating Faults (AREA)

Abstract

In a process for detecting a branch circuit (14A, 14B, ...) subject to earth leaks in an electric power supply or distribution system, in which an earth leak quenching choke (2) is inserted between the mains neutral point and earth, with mains operation switched off, the difference for each individual circuit (14A, 14B, 14C) of the admittances resulting as the quotient of the branch zero current and the neutral point earth voltage is determined before and after each change in the neutral point impedance and the circuit in which this difference is at its maximum is taken as the one subject to earth leaks. The quench coil is plunger choke coil (2) in which the plunger setting is altered between the measurements. The admittances of the individual circuits (14A, 14B, 14C) are calculated from measurements of the branch zero currents as the sum of the three branch phase currents (e.g. with a Holmgreen circuit) and the biasing voltage between the neutral point and earth, taking account of the phase relationship between the zero currents and biasing voltage and complexly subtracted for each individual branch.

Description

Verfahren zur Bestimmung eines erdschlu߬ behafteten Abzweigstrpmkreises in einem elektrischen Versorgungs- oder Verteilernetz Method for determining a branch circuit with an earth fault in an electrical supply or distribution network
Die Erfindung betrifft ein Verfahren zur Bestimmung eines erdschlußbehafteten Abzweigstromkreises in einem elektri¬ schen Versorgungs- oder Verteilernetz, bei dem zwischen Netz- bzw. Transformatorsternpunkt und Erde eine Erdschluß- Löschdrossel geschaltet ist, wobei bei gelöschtem Netzbe¬ trieb für jeden einzelnen Stromkreis die Differenz der sich als Quotienten von Abzweignullstrom und Verlagerungs¬ spannung in Betrag und Phase ergebenden Leitwerte vor und nach einer Änderung der Sternpunktimpedanz bestimmt und jener Stromkreis, bei dem diese Differenz maximal, also un¬ gleich näherungsweise Null ist, als erdschlußbehaftet bewer¬ tet wird.The invention relates to a method for determining a branch circuit with earth faults in an electrical supply or distribution network, in which an earth fault quenching choke is connected between the network or transformer star point and earth, the difference between the for each individual circuit when the network operation is cleared the conductance values obtained before and after a change in the neutral point impedance are determined as quotients of the branch zero current and the displacement voltage in magnitude and phase, and the circuit in which this difference is at a maximum, that is to say approximately equal to zero, is rated as having a ground fault.
Ein Verfahren dieser Art hat gegenüber anderen bekannten Verfahren die gesonderte Erdschlußrichtungs- und Erdschlu߬ zwischenrelais für die einzelnen Abzweigstromkreise vorse¬ hen den Vorteil, daß es nur wenige Meßstellen benötigt, wo¬ bei auch bei Erdschlüssen mit nur geringen Verlagerungsspan¬ nungen infolge hoher Erdübergangswiderstände noch eine Feh- lerortung möglich ist. Das Verfahren wird vor allem bei Strahlennetzen- brauchbar angewendet. Bei Änderungen der Sternpunktimpedanz kommt es in gesunden Abzweigen zu keiner Änderung des oben genannten Leitwertes, wogegen im erdschlu߬ behafteten Abzweig der Leitwert wegen der Ableitung zur Erde eine Veränderung erfährt, so daß die Differenz der Leit¬ werte vor und nach der Änderung der Sternpunktimpedanz un¬ gleich Null wird.Compared to other known methods, a method of this type has the separate earth fault directional and earth fault intermediate relays for the individual branch circuits, which has the advantage that it requires only a few measuring points, even with earth faults with only low displacement voltages due to high earth contact resistances fault location is possible. The method is mainly used for radiation networks. For changes, the star point impedance occurs in healthy branching to no change in the above-mentioned conductance, whereas in erdschlu߬ affected branch of the conductance due to the discharge to earth e i n e change found, so that the difference of Leit¬ values before and after the change the neutral point impedance is not equal to zero.
Aufgabe der Erfindung ist es, ein Verfahren anzugeben, das O 92/18872 PCT/ATO/OOOSSThe object of the invention is to provide a method which O 92/18872 PCT / ATO / OOOSS
- 2 -- 2 -
anzugeben, das mit einfachen Mitteln und vor allem ohne Än¬ derungen des Netzes bzw. der Erdschluß-Löschdrossel im Lei¬ stungsteil eine genügend empfindliche und im Bedarfsfall au¬ tomatisierbare Bestimmung eines erdschlußbehaftete Abzweig- Stromkreises ermöglicht.Specify that with simple means and above all without changes to the network or the ground fault quenching choke in the power section enables a sufficiently sensitive and, if necessary, automatable determination of a branch circuit with a ground fault.
Die gestellte Aufgabe wird dadurch gelöst, daß als Lösch¬ drossel eine Tauchkern-Drosselspule Verwendung findet und deren Tauchkerneinstellung zwischen den Messungen verändert wird, wobei die Leitwerte der einzelnen Abzweigstromkreise aus Messungen des Abzweignullstromes als Summe der im Ab¬ zweig fließenden Phasenstrδme und der Verlagerungsspannung zwischen Sternpunkt und Erde unter Berücksichtigung der Pha¬ senlage zwischen Nullstrom und Verlagerungsspannung berech- net und für jeden einzelnen Abzweig komplex subtrahiert wer¬ den und jener Abzweig, bei dem diese Differenz maximal ist, als erdschlußbehaftet bewertet wird.The object is achieved in that a plunger choke coil is used as the quenching choke and the plunger core setting is changed between the measurements, the conductance values of the individual branch circuits being measured from measurements of the branch zero current as the sum of the phase currents flowing in the branch and the displacement voltage between The star point and earth are calculated taking into account the phase position between zero current and zero sequence voltage and are subtracted for each individual branch in a complex manner, and the branch where this difference is at a maximum is rated as having a ground fault.
Eine Tauchkern-Drosselspule hat an sich den Vorteil, daß sie bei einem auftretenden Erdschluß auf oder in die Nähe eines Resonanzpunktes eingestellt werden kann, bei dem in einem gedachten Ersatzschaltbild eines Parallelresonanzkreises aus Spuleninduktivität, der Summe der Ohmschen Ableitungen und der Summenkapazität Resonanz herrscht, um so die Erdschluß- lδschung zu begünstigen. Beim erfindungsgemäßen Verfahren genügen einfache Meßablei ungen und ein Rechner, um die notwendigen Bestimmungen ohne aufwendige Zusatzeinrichtungen insbesondere -im Leistungsteil des Netzes bzw. der Drossel¬ spule durchführen zu können. Im Normalfall wird die Tauch- kern-Drosselspule bei der ersten Messung im wesentlichen auf Resonanz eingestellt sein und wird aus dieser Einstel¬ lung um ein vorgegebenes Ausmaß für den zweiten Meßzyklus verstimmt.A plunger choke coil has the advantage in itself that it can be set to or in the vicinity of a resonance point in the event of an earth fault in which an imaginary equivalent circuit diagram of a parallel resonance circuit consisting of coil inductance, the sum of the ohmic derivatives and the total capacitance resonates so to favor the earth fault cancellation. In the method according to the invention, simple measurement cables and a computer are sufficient to be able to carry out the necessary determinations without complex additional devices, in particular in the power section of the network or the choke coil. In the normal case, the plunger choke coil will be set essentially to resonance in the first measurement and will be detuned from this setting by a predetermined amount for the second measurement cycle.
Theoretisch und praktisch kann das erfindungsgemäße Ver¬ fahren aber auch dann durchgeführt werden, wenn nur die Be- dingung erfüllt ist , daß die beiden Meßpunkte unterschiedli¬ chen Spulenpositionen entsprechen. Es ist möglich , über den Rechner die Antriebseinrichtung der Tauchkern-Drosselspule für die Verstimmung der Drosselspule nach dem ersten Meßzy¬ klus und die Rückstellung bzw. Einstellung au f den Resonanz¬ punkt nach dem zweiten Meßzyklus zu steuern, wobe i dieser Re¬ sonanzpunkt in Ergänzung des beschriebenen Verfahrens durch Anfahren einer dritten Tauchkernposition ermittelt werden kann .Theoretically and practically, however, the method according to the invention can also be carried out if only the loading condition is fulfilled that the two measuring points correspond to different coil positions. It is possible to control the drive device of the plunger core choke coil for detuning the choke coil after the first measurement cycle and for resetting or adjusting the resonance point after the second measurement cycle, the resonance point in FIG Supplementing the described method can be determined by moving to a third plunger position.
Weitere Einzelheiten und Vorteile des Erfindungsgegenstandes entnimmt man der nachfolgenden Zeichnungsbeschreibung.Further details and advantages of the subject matter of the invention can be found in the following description of the drawings.
In der Zeichnung ist der Erf indungsgegenstand beispielsweise dargestellt . Es zeigenThe subject of the invention is shown in the drawing, for example. Show it
Fig . 1 ein zur Durchführung des erfindungsgemäßen Verfahrens verwendbares Meßsystem im Blockschema undFig. 1 shows a measuring system which can be used to carry out the method according to the invention in a block diagram, and
Fig . 2 ein Ersatzschaltbild für einen mit der Erdschluß- Löschdrossel verbundenen, erdschlußbehafteten Abzweig¬ stromkreis zur Erläuterung des erfindungsgemäßen Ver¬ fahrens .Fig. 2 shows an equivalent circuit diagram for a branch circuit with an earth fault connected to the earth fault quenching choke to explain the method according to the invention.
In Fig. 1 ist in schematischer Darstellung eine Gerätean¬ ordnung zur Bestimmung eines erdschlußbehafteten Abzweiges in einem Strahlennetz dargestellt. Der Sternpunkt der Sekun¬ därseite eines Netztransformators 1 ist mit einer Tauchkern- Drosselspule 2 verbunden, deren Tauchkern mit Hilfe einer Antriebseinrichtung 3 verstellt werden kann. Die an der Dros¬ selspule 2 anliegende Verlagerungsspannung zwischen Stern- punkt und Erde wird über einen Spannungswandler -4 erfaßt und transformiert und anschließend in einer weiteren Wandler¬ stufe mit Bandpaßfilter 5 angepaßt und von Oberwellen be¬ freit. In einer Signalaufbereitungseinheit 6 wird der Effek¬ tivwert der Meßgröße ermittelt und nachfolgend mit Hilfe eines A/D-Wandlers in digitale Form gebracht und an einen Rechner 12 weitergeleitet. Ferner wird in 6 ein zur Meßgröße phasengleiches Rechtecksignal zur digitalen Weiterverarbei¬ tung abgeleitet und an den Rechner 12 abgegeben.1 shows a schematic representation of an arrangement of devices for determining a branch with a ground fault in a radiation network. The star point of the secondary side of a power transformer 1 is connected to a plunger choke coil 2, the plunger core of which can be adjusted with the aid of a drive device 3. The displacement voltage present between the star point and earth at the choke coil 2 is detected and transformed via a voltage converter -4 and then adapted in a further converter stage with a bandpass filter 5 and freed from harmonics. The effective value of the measured variable is determined in a signal processing unit 6 and subsequently brought into digital form with the aid of an A / D converter and passed on to a computer 12. 6 also becomes a measured variable in-phase square wave signal for digital further processing derived and output to the computer 12.
In allen Abzweigen 14A, 14B, 14C... des Netzes 14 werden über Summenstromwandler 7A, 7B, 7C..., z. B. in Holmgreen¬ schaltung, die den jeweiligen Abzweigen zugeordneten Null¬ ströme ermittelt und nachfolgend über galvanisch trennendeIn all branches 14A, 14B, 14C ... of the network 14 are summation current transformers 7A, 7B, 7C ..., z. B. in Holmgreen¬ circuit, which determines the respective branches assigned zero currents and subsequently via galvanically isolating
I/Ü-Wandler 8A, 8B, 8C in eine elektronisch auswertbareI / Ü converter 8A, 8B, 8C into an electronically evaluable
Form gebracht. Ein vom Rechner 12 gesteuerter Signalmulti- plexer 9 schaltet das über den Rechner 12 auswählbare Null¬ stromsignal an einen Bandpaßfilter 10, wo es von Oberwellen • befreit und einer Signalaufbereitungseinheit 11 zugeführt wird, in der der Effektivwert des ausgewählten, gefilterten Nullstromsignales gebildet und über einen A/D-Wandler in di- gitale Form gebracht wird. Auch in der Signalaufbereitungs¬ einheit 11 wird ein zur Meßgröße phasengleiches Rechtecksig¬ nal gebildet und ebenso wie der Digitalwert des Effektivwer¬ tes der Meßgröße an den Rechner 12 weitergeleitet.Formed. A controlled by the computer 12 Signalmulti- plexer 9 switches the selectable via the computer 12 Null¬ current signal to a bandpass filter 10 where it is freed from harmonics and • a signal processing unit 11 is supplied, in the formed the effective value of the selected filtered residual current signal, and a A / D converter is brought into digital form. Also in the signal processing unit 11, a rectangular signal in phase with the measured variable is formed and, like the digital value of the effective value of the measured variable, is passed on to the computer 12.
Im Falle eines Erdschlusses werden bei einer in der Nähe der Resonanzabstimmung liegenden Spulenposition mittels des Sig- nalmultiplexers 9 alle den Abzweigen 14A, 14B, 14C... zuge¬ ordneten Wandler 8A, 8B, 8C usw. angewählt und die erhalte¬ nen Meßdaten für die Nullströme erfaßt. Gleichzeitig wer-den Meßdaten der Sternpunkt-Erdspannung über 4, 5, 6 erfaßt und dem Rechner zugeführt. Im Rechner 12 werden für alle Ab¬ zweige 14A, 14B, 14C die Quotienten aus den Effektivwerten der Nullströme und dem E fektivwert der momentanen Verla¬ gerungsspannung berechnet und auch die Phasenverschiebung des jeweiligen Nullstromes zur Verlagerungsspannung bestimmt und die so durch Betrag und Phase für jeden Abzweig komplex ermittelten Leitwerte gespeichert. Anschließend wird der Tauchkern der Tauchkernspule 2 über die Antriebseinrichtung 3 im Sinne einer Verstimmung verstellt, wobei diese Verstel- lung ebenfalls vom Rechner 12 aus gesteuert werden kann. Nachfolgend werden die in der ersten Stellung des Tauchkernes durchgeführten Messungen wiederholt und die Berechnung der komplexen Leitwerte vorgenommen, wobei die entsprechenden Werte wieder gespeichert werden. Nachfolgend werden für je¬ den Abzweig 14A, 14B, 14C... die bei dem ersten Meßzyklus (vor der Tauchkernspulenverstellung) ermittelten Leitwerte von den im zweiten Meßzyklus (nach der Tauchkernspulenver¬ stellung) ermittelten Leitwerten komplex subtrahiert. Jener Abzweig, bei dem der Betrag der Differenz der beiden Leit¬ werte maximal ist, wird als erdschlußbehaftet erkannt und es wird für ihn eine entsprechende Speicherung vorgenommen. Nun wird der gesamte Vorgang wiederholt. Wird der gleiche Abzweig noch einmal als erdschlußbehaftet identifiziert, wird das Ergebnis auf einer Anzeigeeinheit 13 angezeigt. Sonst wird der Meßvorgang so oft wiederholt, bis bei zwei aufeinander- folgenden Meßvorgängen der gleiche Abzweig als erdschlußbe¬ haftet identifiziert wurde.In the event of an earth fault, in the case of a coil position in the vicinity of the resonance tuning, all transducers 8A, 8B, 8C etc. assigned to the branches 14A, 14B, 14C, etc. are selected by means of the signal multiplexer 9, and the measurement data obtained for the zero currents detected. At the same time, the measurement data of the neutral point earth voltage are acquired via 4, 5, 6 and fed to the computer. In the computer 12, the quotients from the effective values of the zero currents and the effective value of the instantaneous displacement voltage are calculated for all branches 14A, 14B, 14C and also the phase shift of the respective zero current to the displacement voltage is determined, and this by amount and phase for each Branch, complex, determined guide values saved. The plunger core of the plunger core coil 2 is then adjusted via the drive device 3 in the sense of detuning, wherein this adjustment can also be controlled from the computer 12. Below are those in the first position of the plunger measurements carried out repeatedly and the calculation of the complex master values carried out, the corresponding values being stored again. Subsequently, for each branch 14A, 14B, 14C ..., the master values determined in the first measuring cycle (before the moving core coil adjustment) are subtracted in a complex manner from the leading values determined in the second measuring cycle (after the moving core coil adjustment). The branch in which the difference between the two leading values is at a maximum is recognized as having a ground fault and a corresponding storage is carried out for it. Now the whole process is repeated. If the same branch is identified again as having a ground fault, the result is displayed on a display unit 13. Otherwise, the measuring process is repeated until the same branch has been identified as having a ground fault in two successive measuring processes.
Im Schaltschema nach Fig. 2 ist ein Ersatzschaltbild für einen Abzweigstromkreis, z. B. 14A, dargestellt. Die Tauch- kernspule 2 liegt am Sternpunkt des Transformators 1. Die drei Phasen dieses Abzweigstromkreises haben gegenüber Erde meßbare Phasenspannungen. Im Schaltbild wurden mit gR, gs, gm die Leitwerte der Ohmschen Ableitungen der einzelnen Pha¬ sen gegen Erde und mit CR, C«,, Cm die Kapazität der einzel- nen Phasen gegen Erde bezeichnet. Im Falle eines Erdschlus¬ ses, der für die oberste Phase angenommen wurde, hat dieser gegenüber Erde einen Leitwert g«. des Erdschlußwiderstandes. Im Abzweig fließt ein z. B. mit Hilfe einer Holmgreenschal¬ tung ermittelter Nullstrom i und an der Drossel 2 liegt wieder eine Verlagerungsspannung UNE an. Bei Vorhandensein' eines Erdschlusses ändert sich der als Quotient von Null¬ strom und Verlagerungsspannung in Betrag und Phase ermit¬ telte Leitwert des Abzweiges bei den beiden Einstellungen der Spule 2 auch dann, wenn der Erdschlußwiderstand sehr hochohmig ist, so daß der Abzweig als erdschlußbehaftet iden¬ tifiziert werden kann. 2 is an equivalent circuit diagram for a branch circuit, for. B. 14A. The plunger core coil 2 is located at the star point of the transformer 1. The three phases of this branch circuit have phase voltages that can be measured with respect to earth. In the diagram were g R, g s, the conductances gm of the ohmic derivatives of the individual Pha¬ sen to earth and with C R, C ",, Cm denotes the capacitance of the individual phases to earth. In the case of an earth fault that was assumed for the uppermost phase, this has a conductance g «with respect to earth. the earth fault resistance. In the branch flows a z. B. with the help of a Holmgreenschal¬ device determined zero current i and at the inductor 2 there is again a zero sequence voltage U NE . In the presence 'of an earth fault of the coil 2 changes as the quotient of the current of Null¬ and residual voltage in magnitude and phase ermit¬ Telte conductance of the branch in the two settings, even if the ground fault resistance is very high impedance, so that the branch iden as erdschlußbehaftet ¬ can be certified.

Claims

P a t e n t a n s p r u c h : P a t e n t a n s r u c h:
Verfahren zur Bestimmung eines erdschlußbehafteten Abzweig¬ stromkreises (14A, 14B...) in einem elektrischen Versor¬ gungs- oder Verteilernetz, bei dem zwischen Transformator¬ sternpunkt und Erde eine Erdschluß-Löschdrossel (2) geschal- tet ist, wobei bei gelöschtem Netzbetrieb für jeden einzel¬ nen Stromkreis (14A, 14B, 14C) die Differenz der sich als Quotienten von Abzweignullstrom und Verlagerungsspannung in Betrag und Phase ergebenden Leitwerte vor und nach einer Änderung der Sternpunktimpedanz bestimmt und jener Strom- kreis, bei dem diese Differenz maximal ist, als erdschlu߬ behaftet bewertet wird, dadurch gekennzeichnet, daß als Löschdrossel eine Tauchkern-Drosselspule (2) Verwendung fin¬ det und deren Tauchkerneinstellung zwischen den Messungen verändert wird, wobei die Leitwerte der einzelnen Abzweig- Stromkreise (14, 14A, 14B, 14C....) aus Messungen des Ab¬ zweignullstromes als Summe der im Abzweig fließenden Pha¬ senströme und der VerlagerungsSpannung zwischen Sternpunkt und Erde unter Berücksichtigung der Phasenlage zwischen Nullstrom und VerlagerungsSpannung berechnet und für jeden einzelnen Abzweig komplex subtrahiert werden und jener Abzweig, bei dem diese Differenz ungleich Null ist, als erdschlußbehaftet bewertet wird. Method for determining a branch circuit (14A, 14B ...) with an earth fault in an electrical supply or distribution network, in which an earth fault quenching choke (2) is connected between the transformer star point and earth, with the network operation being cleared for each individual circuit (14A, 14B, 14C), the difference between the conductance values resulting in quotient from the branch zero current and the displacement voltage in magnitude and phase is determined before and after a change in the neutral point impedance, and the circuit in which this difference is at a maximum, is rated as earth fault, characterized in that a plunger choke coil (2) is used as the quenching choke and the plunger core setting is changed between the measurements, the conductance values of the individual branch circuits (14, 14A, 14B, 14C. ...) from measurements of the branch zero current as the sum of the phase currents flowing in the branch and the displacement voltage between The star point and earth are calculated taking into account the phase relationship between zero current and zero sequence voltage and are complexly subtracted for each individual feeder and the feeder where this difference is not equal to zero is rated as having a ground fault.
PCT/AT1992/000053 1991-04-19 1992-04-21 Process for detecting a branch circuit subject to earth leaks in an electric power supply or distribution system WO1992018872A1 (en)

Applications Claiming Priority (2)

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AT82091 1991-04-19
ATA820/91 1991-04-19

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WO1992018872A1 true WO1992018872A1 (en) 1992-10-29

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PCT/AT1992/000053 WO1992018872A1 (en) 1991-04-19 1992-04-21 Process for detecting a branch circuit subject to earth leaks in an electric power supply or distribution system

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WO (1) WO1992018872A1 (en)

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WO1995027904A1 (en) * 1994-04-07 1995-10-19 Aeg Bahnfahrwegsysteme Gmbh Device for checking the insulation condition of alternating-current-carrying lines or cables
WO1996027138A1 (en) * 1995-02-28 1996-09-06 Haefely Trench Austria Gmbh Unipolar earth leakage recognition process for three phase mains
EP1443336A2 (en) * 1998-11-20 2004-08-04 Adaptive Regelsysteme Gesellschaft mbH Method of detecting a branch with an earth fault
DE10307972A1 (en) * 2003-02-24 2004-09-09 Edc Gmbh Earth connection method for recognizing and locating earth connections with low and high impedance measures frequencies different from a mains frequency

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EP0083306A1 (en) * 1981-12-22 1983-07-06 Elektrizitätswerke des Kantons Zürich Process and device to control at least one compensation coil in a polyphase network
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EP0069790A1 (en) * 1981-07-10 1983-01-19 Jozsef Dipl.-Ing. Prause Method and device for locating earth faults of power line networks
EP0083306A1 (en) * 1981-12-22 1983-07-06 Elektrizitätswerke des Kantons Zürich Process and device to control at least one compensation coil in a polyphase network
EP0164321A1 (en) * 1984-03-12 1985-12-11 Klaus Winter Device for limiting an earth fault current in heavy-current systems
WO1986003350A1 (en) * 1984-11-19 1986-06-05 Klaus Winter Power systems
DE3643391A1 (en) * 1986-01-31 1987-08-06 Licentia Gmbh Method for the automatic adjustment of earth-fault suppression coils
EP0398824A1 (en) * 1989-05-19 1990-11-22 Merlin Gerin Numerical insulation tester for powder system
DE3920177A1 (en) * 1989-06-16 1990-12-20 Licentia Gmbh Earth connection detection for unearthed multiphase supply networks - charging network capacitance with DC and measuring isolation characteristics indirectly

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1995027904A1 (en) * 1994-04-07 1995-10-19 Aeg Bahnfahrwegsysteme Gmbh Device for checking the insulation condition of alternating-current-carrying lines or cables
WO1996027138A1 (en) * 1995-02-28 1996-09-06 Haefely Trench Austria Gmbh Unipolar earth leakage recognition process for three phase mains
AT404072B (en) * 1995-02-28 1998-08-25 Haefely Trench Austria Gmbh METHOD FOR DETECTING A SINGLE-POLE EARTH FAULT IN A THREE-PHASE NETWORK
EP1443336A2 (en) * 1998-11-20 2004-08-04 Adaptive Regelsysteme Gesellschaft mbH Method of detecting a branch with an earth fault
EP1533623A2 (en) * 1998-11-20 2005-05-25 Adaptive Regelsysteme GmbH Method of detecting a branch with an earth fault
EP1443336A3 (en) * 1998-11-20 2005-12-14 Adaptive Regelsysteme Gesellschaft mbH Method of detecting a branch with an earth fault
EP1533623A3 (en) * 1998-11-20 2010-10-06 Adaptive Regelsysteme GmbH Method of detecting a branch with an earth fault
DE10307972A1 (en) * 2003-02-24 2004-09-09 Edc Gmbh Earth connection method for recognizing and locating earth connections with low and high impedance measures frequencies different from a mains frequency
DE10307972B4 (en) * 2003-02-24 2007-02-08 Edc Gmbh Method for detecting and locating low-resistance and high-impedance ground faults in electrical supply networks
AT500004B1 (en) * 2003-02-24 2007-09-15 Edc Gmbh METHOD FOR DETECTING AND LOCATING AN EARTH LOCK

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