EP0603857A1 - Ring core transformer with parasitic voltage shielding - Google Patents
Ring core transformer with parasitic voltage shielding Download PDFInfo
- Publication number
- EP0603857A1 EP0603857A1 EP93120690A EP93120690A EP0603857A1 EP 0603857 A1 EP0603857 A1 EP 0603857A1 EP 93120690 A EP93120690 A EP 93120690A EP 93120690 A EP93120690 A EP 93120690A EP 0603857 A1 EP0603857 A1 EP 0603857A1
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- EP
- European Patent Office
- Prior art keywords
- winding
- current transformer
- toroidal
- shield
- metallic
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F38/00—Adaptations of transformers or inductances for specific applications or functions
- H01F38/20—Instruments transformers
- H01F38/22—Instruments transformers for single phase ac
- H01F38/28—Current transformers
- H01F38/30—Constructions
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F27/00—Details of transformers or inductances, in general
- H01F27/34—Special means for preventing or reducing unwanted electric or magnetic effects, e.g. no-load losses, reactive currents, harmonics, oscillations, leakage fields
- H01F27/36—Electric or magnetic shields or screens
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F27/00—Details of transformers or inductances, in general
- H01F27/34—Special means for preventing or reducing unwanted electric or magnetic effects, e.g. no-load losses, reactive currents, harmonics, oscillations, leakage fields
- H01F27/36—Electric or magnetic shields or screens
- H01F27/363—Electric or magnetic shields or screens made of electrically conductive material
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F38/00—Adaptations of transformers or inductances for specific applications or functions
- H01F38/20—Instruments transformers
- H01F38/22—Instruments transformers for single phase ac
- H01F38/28—Current transformers
- H01F38/30—Constructions
- H01F2038/305—Constructions with toroidal magnetic core
Definitions
- the invention relates to a toroidal current transformer for installation in a metal encapsulation which is at ground potential and surrounds a high-voltage conductor and has at least one toroid which has a winding with leads passing through the metal encapsulation and a metallic shield surrounding the winding.
- Such a toroidal current transformer is known for example from DE-OS 41 06 034.
- the metallic shield consists of an earthed winding applied to the toroidal core.
- the leads of the current transformer carrying the measuring signal are led out of the metal encapsulation for connection to a measuring device.
- transient overvoltages can occur, for example due to the actuation of isolating switches, which lead to disturbances in the form of traveling waves within the metal encapsulation.
- Such transient overvoltages can generate high interference voltages in a current transformer, which can lead to considerable interference in the connected measuring electronics during operation of the current transformer.
- the invention is therefore based on the object of designing a current transformer of the type mentioned in such a way that the interference potential is further reduced by transient overvoltages.
- the metallic shield is of low-resistance and low-inductance, the metallic shield being formed by a conductive layer, in particular film or fabric, which has an insulating gap to avoid a short-circuit winding.
- the shielding and its low impedance and low inductance effectively prevent the formation of transient overvoltages, which are induced in the supply lines as a result of electrical converter waves. This also means that there are no overvoltages at the measuring connections, which can damage the connected instruments.
- the protective circuits of the measuring instruments otherwise provided can advantageously be omitted.
- Such a shielding film which can be formed either by a metallized plastic film or a metal film, for example, provides an ideal seal and metallic encapsulation of the windings against disruptive electromagnetic influences.
- the foil must have an insulated gap in order to avoid a short circuit turn around the toroid in which high currents would flow.
- the film can have a gap at which the winding of the current transformer is exposed.
- the film may have an insulating layer above its electrically conductive layer.
- the supply lines have a metallic shield shell, the first end of which is arranged directly on the metallic shield and is conductively connected thereto, and that the metallic shield shell is connected to the earth potential at its second end in the region of a measuring connection.
- the first end of the metallic shielding sheath it is necessary for the first end of the metallic shielding sheath to be arranged directly on the shielding and to be conductively connected to it. In the area of the exit of the leads from the winding, there is no section in which electrical disturbances penetrate the leads. It is also important that the metallic shield cover is connected to the earth potential at its second end in the area of a measuring connection, so that a defined reference potential is available at this second end.
- the metallic shield has an interference voltage potential with respect to the metal encapsulation due to the influence of the electrical interference. It is important that the differential voltage to be measured that occurs between the supply lines and the metallic shield is as great as the voltage between the supply lines and the metal encapsulation in the area of the measuring connection.
- the electrical interference potentials on the metallic shield and the metallic shield shell are compensated for by currents which flow along the metallic shield and the metallic shield shell to the measuring connection and from there via the ground back to the metal encapsulation of the switchgear. Such compensating currents have no influence on the voltages to be measured.
- the invention can be advantageously designed in such a way that the supply lines have a shielding jacket which at least partially surrounds the metallic shielding cover, which is conductively connected to a grounded shielding electrode surrounding the current transformer and is likewise connected to the ground potential in the area of the measuring connection.
- This additional shielding jacket is insulated from the shielding cover and has the effect that electrical disturbances only lead to interference potentials on the shielding cover and not to interference potentials on the metallic shielding cover, so that the equalizing currents flow through the shielding cover to compensate for the interference potential and not through the metallic shielding cover.
- the layer of metallic shielding is designed as a meandering tape winding with a changing winding direction, preferably after almost every complete turn. This results in a low inductance.
- the film is designed as a tape winding with the winding layer insulated from one another on the ring core.
- a metallized tape can be used as the film, which is provided on one side with an adhesive layer and on the other side with an insulating layer. The winding must not be closed to avoid a short circuit current around the toroid.
- Such a tape winding can be easily applied in terms of production technology.
- Interference voltages are also further reduced in that the metallic shield is applied in a partially overlapping manner and consists of a band whose surface conducts.
- the measure that a semiconducting sheath is additionally provided also has a positive effect on the suppression of interference voltages.
- the semiconducting layer can be provided both below and above the metallic shield.
- windings are in contact with the flat semiconducting sheath in a conductive, preferably flat, manner.
- a further reduction in the interference voltages is achieved if a shield made of metal tape which is insulated on all sides is additionally provided, at least in the area of the supply line.
- a cylindrical toroidal current transformer 2 is arranged within a tubular part of a metal encapsulation 1. For the sake of clarity, only one toroidal core 3 is shown in FIG. 1.
- the ring cores surround a conductor 4 carrying high voltage and are shielded from the electric field by a shield electrode 5, 28.
- the shield electrode 5 has a gap 6, through which the shield electrode 5 with the metal encapsulation 1 is prevented from forming a short-circuit turn around the ring core 3, in which a ring current would be induced through the current flowing through the high-voltage conductor 4. However, electrical interferences still enter the area of the ring cores 3 through the gap 6.
- Each toroidal core is surrounded by a secondary winding 7 symbolically represented in the figure, in which an electrical signal dependent on the current in the high-voltage conductor 4 is generated by induction. the electrical signal is fed through the leads 8, 9 to a measuring connection 10.
- the ring cores are each surrounded by a shield 11 in the form of a shielding film, which is interrupted by a schematically illustrated gap 12 in order to avoid a short-circuit winding.
- the feed lines 8, 9 have a metallic shield sleeve 13, which directly at its first end 14 is conductively connected to the film 11. At its second end 15, the shield cover 13 is grounded in the area of the measuring connection 10. It is taken into account that the connection of the shield sleeve 13 or the shield jacket 16 to the ground potential of the measuring connection 10 is designed such that the leads 8, 9 are also shielded as well as possible in this area and that the earth connection of the shield sleeve 13 or the shield jacket 16 is as short as possible.
- a shielding jacket 16 surrounding the shielding sleeve 13 is provided, which surrounds the feed lines 8, 9 and the shielding sleeve 13 and is grounded in the area of the measuring connection 10. As a result, no compensating currents are induced in the shield cover 11. This results in a further reduction in the interference voltage potential.
- the shield 11 is shown as a meandering winding from tape 17 over the lower left sector. This becomes visible when the outer tape insulation 25 and the covering protective winding 24 (FIG. 4) are removed in the sector mentioned.
- the winding is clearer in Figure 3, which shows a view according to arrow III in the area of the feed line.
- the shield 11 consists of a metallic tape 17, for example a metallic fabric tape, the surface of which is elastically conductive.
- the winding is meandering.
- band 17 is first laid with a certain pitch around the ring core with winding and protective fuse, which is of a customary construction, until it reaches a split band 18. It is passed under the insulating split tape and then on edge 19 of the split tape 18 deflected in the opposite direction and again guided around the ring core until it reaches the slit band 18 again. The next partial turn then follows in the opposite direction as described above.
- the individual turns 20, 21 thus each have an opposite winding direction and do not touch at the deflection points. In this way, short-circuit turns are avoided.
- the end of the tape is conductively connected to the shield sleeve 13 of the leads.
- the shield cover 13 ideally consists of the individual shield covers 22, 23, which surround each supply line separately.
- a further lowering of the interference voltage potential results if, at least in the area of the feed lines 8, 9, the shield 11 is additionally provided with a protective winding 24, which is made, for example, from mutually insulated winding layers of a metallized strip.
- This tape can, for example, be provided on one side with an adhesive layer and on the other side with an insulating layer. The windings must not be closed to avoid a short-circuit current around the toroid.
- an insulating layer can then be applied on the outside in a generally known manner.
- this additional protective winding 24 is shown from a metal tape insulated at least on one side.
- Each feed line 8, 9 initially has its own individual shield cover 22, 23, which in turn is surrounded by the shield cover 13.
- the secondary winding of the toroidal core 3 is first provided with protective insulation (not shown), on which an additional semiconducting layer may also be applied.
- This semiconducting layer then forms the base 27 (FIGS. 4 and 1) for the metallic shield 11, the individual turns of which are applied to the surface of the semiconducting layer and touch it in a conductive manner.
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Regulation Of General Use Transformers (AREA)
- Transformers For Measuring Instruments (AREA)
- Coils Or Transformers For Communication (AREA)
- Emergency Protection Circuit Devices (AREA)
Abstract
Description
Die Erfindung bezieht sich auf einen Ringkernstromwandler zum Einbau in eine auf Erdpotential liegende, einen Hochspannungsleiter umgebende Metallkapselung mit wenigstens einem Ringkern, der eine Wicklung mit die Metallkapselung durchsetzenden Zuleitungen und eine die Wicklung umgebende metallische Abschirmung aufweist.The invention relates to a toroidal current transformer for installation in a metal encapsulation which is at ground potential and surrounds a high-voltage conductor and has at least one toroid which has a winding with leads passing through the metal encapsulation and a metallic shield surrounding the winding.
Ein derartiger Ringkernstromwandler ist beispielsweise aus der DE-OS 41 06 034 bekannt. Bei dem dort dargestellten Stromwandler besteht die metallische Abschirmung aus einer auf den Ringkern aufgebrachten, geerdeten Wicklung. Die das Meßsignal führenden Zuleitungen des Stromwandlers sind zum Anschluß an ein Meßgerät aus der Metallkapselung herausgeführt.Such a toroidal current transformer is known for example from DE-OS 41 06 034. In the current transformer shown there, the metallic shield consists of an earthed winding applied to the toroidal core. The leads of the current transformer carrying the measuring signal are led out of the metal encapsulation for connection to a measuring device.
Innerhalb einer Schaltanlage, in die ein derartiger Ringkernstromwandler eingebaut ist, können, beispielsweise durch die Betätigung von Trennschaltern, transiente Überspannungen auftreten, die zu Störungen in Form von Wanderwellen innerhalb der Metallkapselung führen. In einem Stromwandler können durch solche transienten Überspannungen hoher Störspannungen erzeugt werden, die beim Betrieb des Stromwandlers zu erheblichen Störungen in der angeschlossenen Meßelektronik führen können.Within a switchgear in which such a toroidal core current transformer is installed, transient overvoltages can occur, for example due to the actuation of isolating switches, which lead to disturbances in the form of traveling waves within the metal encapsulation. Such transient overvoltages can generate high interference voltages in a current transformer, which can lead to considerable interference in the connected measuring electronics during operation of the current transformer.
Der Erfindung liegt daher die Aufgabe zugrunde, einen Stromwandler der eingangs genannten Art derart auszubilden, daß das Störpotential durch transiente Überspannungen weiter reduziert wird.The invention is therefore based on the object of designing a current transformer of the type mentioned in such a way that the interference potential is further reduced by transient overvoltages.
Diese Aufgabe wird erfindungsgemäß dadurch gelöst, daß die metallische Abschirmung niedrigohmig und niedriginduktiv ausgebildet ist, wobei die metallische Abschirmung durch eine leitende Schicht, insbesondere Folie oder Gewebe, gebildet ist, die zur Vermeidung einer Kurzschlußwicklung einen isolierenden Spalt aufweist. Durch die Abschirmung und deren Niederohmigkeit und niedrige Induktivität wird die Entstehung von transienten Überspannungen, die infolge elektrischer Wandlerwellen in den Zuleitungen induziert werden, wirkungsvoll vermieden. Dadurch entstehen auch keine Überspannungen an den Meßanschlüssen, die zu Schäden an den angeschlossenen Instrumente führen können. Die sonst vorgesehenen Schutzbeschaltungen der Meßinstrumente können vorteilhaft entfallen. Durch eine solche Abschirmfolie, die beispielsweise entweder durch eine metallisierte Kunststoffolie oder durch eine Metallfolie gebildet sein kann, ist eine ideale Abdichtung und metallische Kapselung der Wicklungen gegen störende elektromagnetische Einflüsse gegeben. Die Folie muß einen isolierten Spalt aufweisen, um eine Kurzschlußwindung um den Ringkern zu vermeiden, in der hohe Ströme fließen würden. Zu diesem Zweck kann die Folie einen Spalt aufweisen, an dem die Wicklung des Stromwandlers freiliegt. Es ist aber auch denkbar, die Folie im Bereich des Spaltes unter Zwischenlage einer Isolierschicht überlappen zu lassen, um auf diese Weise den Spalt möglichst klein zu gestalten. Es kann beispielsweise die Folie oberhalb ihrer elektrisch leitenden Schicht eine Isolierschicht aufweisen.This object is achieved in that the metallic shield is of low-resistance and low-inductance, the metallic shield being formed by a conductive layer, in particular film or fabric, which has an insulating gap to avoid a short-circuit winding. The shielding and its low impedance and low inductance effectively prevent the formation of transient overvoltages, which are induced in the supply lines as a result of electrical converter waves. This also means that there are no overvoltages at the measuring connections, which can damage the connected instruments. The protective circuits of the measuring instruments otherwise provided can advantageously be omitted. Such a shielding film, which can be formed either by a metallized plastic film or a metal film, for example, provides an ideal seal and metallic encapsulation of the windings against disruptive electromagnetic influences. The foil must have an insulated gap in order to avoid a short circuit turn around the toroid in which high currents would flow. For this purpose, the film can have a gap at which the winding of the current transformer is exposed. However, it is also conceivable to have the film overlap in the area of the gap with the interposition of an insulating layer, in order in this way to make the gap as small as possible. For example, the film may have an insulating layer above its electrically conductive layer.
Die Aufgabe wird auch dadurch gelöst, daß die Zuleitungen eine metallische Schirmhülle aufweisen, deren erstes Ende direkt an der metallischen Abschirmung angeordnet und mit dieser leitend verbunden ist und daß die metallische Schirmhülle an ihrem zweiten Ende im Bereich eines Meßanschlusses mit dem Erdpotential verbunden ist. Zur Vermeidung von Überspannungen am Meßanschluß ist es notwendig, daß das erste Ende der metallischen Schirmhülle direkt an der Abschirmung angeordnet ist und mit dieser leitend verbunden ist. Im Bereich des Austritts der Zuleitungen aus der Wicklung ergibt sich dadurch kein Abschnitt, in dem elektrische Störungen die Zuleitungen durchsetzen. Dabei ist es weiterhin wichtig, daß die metallische Schirmhülle an ihrem zweiten Ende im Bereich eines Meßanschlusses mit dem Erdpotential verbunden ist, so daß an diesem zweiten Ende ein definiertes Referenzpotential zur Verfügung steht.The object is also achieved in that the supply lines have a metallic shield shell, the first end of which is arranged directly on the metallic shield and is conductively connected thereto, and that the metallic shield shell is connected to the earth potential at its second end in the region of a measuring connection. To avoid overvoltages at the measuring connection, it is necessary for the first end of the metallic shielding sheath to be arranged directly on the shielding and to be conductively connected to it. In the area of the exit of the leads from the winding, there is no section in which electrical disturbances penetrate the leads. It is also important that the metallic shield cover is connected to the earth potential at its second end in the area of a measuring connection, so that a defined reference potential is available at this second end.
Hierfür ist es ohne Belang, ob die metallische Abschirmung durch den Einfluß der elektrischen Störungen ein Störspannungspotential gegenüber der Metallkapselung aufweist. Wichtig ist, daß die zwischen den Zuleitungen und der metallischen Abschirmung auftretende, zu messende Differenzspannung ebenso groß ist wie im Bereich des Meßanschlusses die Spannung zwischen den Zuleitungen und der Metallkapselung.For this it is irrelevant whether the metallic shield has an interference voltage potential with respect to the metal encapsulation due to the influence of the electrical interference. It is important that the differential voltage to be measured that occurs between the supply lines and the metallic shield is as great as the voltage between the supply lines and the metal encapsulation in the area of the measuring connection.
Die elektrischen Störpotentiale auf der metallischen Abschirmung und der metallischen Schirmhülle werden durch Ströme ausgeglichen, die entlang der metallischen Abschirmung und der metallischen Schirmhülle bis zum Meßanschluß und von dort über die Masse zurück zur Metallkapselung der Schaltanlage fließen. Auf die zu messenden Spannungen haben solche Ausgleichsströme keinen Einfluß.The electrical interference potentials on the metallic shield and the metallic shield shell are compensated for by currents which flow along the metallic shield and the metallic shield shell to the measuring connection and from there via the ground back to the metal encapsulation of the switchgear. Such compensating currents have no influence on the voltages to be measured.
Die Erfindung kann dadurch vorteilhaft ausgestaltet werden, daß die Zuleitungen einen die metallische Schirmhülle wenigstens zum Teil umgebenden Schirmmantel aufweisen, der mit einer den Stromwandler umgebenden geerdeten Schirmelektrode leitend verbunden und im Bereich des Meßanschlusses ebenfalls mit dem Erdpotential verbunden ist.The invention can be advantageously designed in such a way that the supply lines have a shielding jacket which at least partially surrounds the metallic shielding cover, which is conductively connected to a grounded shielding electrode surrounding the current transformer and is likewise connected to the ground potential in the area of the measuring connection.
Dieser zusätzliche Schirmmantel ist gegenüber der Schirmhülle isoliert und bewirkt, daß elektrische Störungen lediglich zu Störpotentialen auf dem Schirmmantel und nicht zu Störpotentialen auf der metallischen Schirmhülle führen, so daß die Ausgleichsströme zum Ausgleich der Störpotentiale durch den Schirmmantel fließen und nicht durch die metallische Schirmhülle.This additional shielding jacket is insulated from the shielding cover and has the effect that electrical disturbances only lead to interference potentials on the shielding cover and not to interference potentials on the metallic shielding cover, so that the equalizing currents flow through the shielding cover to compensate for the interference potential and not through the metallic shielding cover.
Ein besonders guter Schutz gegen Überspannungen ergibt sich, wenn die Schicht der metallischen Abschirmung als meandrierende Bandwicklung ausgebildet ist mit sich änderndem Wickelsinn, vorzugsweise nach annähernd jeder vollständigen Windung. Hierdurch wird eine niedrige Induktivität erreicht.A particularly good protection against overvoltages results if the layer of metallic shielding is designed as a meandering tape winding with a changing winding direction, preferably after almost every complete turn. This results in a low inductance.
Alternativ kann vorgesehen werden, daß die Folie als Bandwicklung mit gegeneinander isolierter Wicklungslage auf dem Ringkern ausgebildet ist. Es kann beispielsweise ein metallisiertes Band als Folie verwendet werden, das auf einer Seite mit einer klebenden Schicht und auf der anderen Seite mit einer isolierenden Schicht versehen ist. Die Wicklung darf nicht geschlossen werden, um einen Kurzschlußstrom um den Ringkern herum zu vermeiden. Eine solche Bandwicklung läßt sich fertigungstechnisch einfach aufbringen.Alternatively, it can be provided that the film is designed as a tape winding with the winding layer insulated from one another on the ring core. For example, a metallized tape can be used as the film, which is provided on one side with an adhesive layer and on the other side with an insulating layer. The winding must not be closed to avoid a short circuit current around the toroid. Such a tape winding can be easily applied in terms of production technology.
Störspannungen werden auch dadurch weiter verringert, daß die metallische Abschirmung teilweise überlappend gewickelt aufgebracht ist und aus einem Band besteht, dessen Oberfläche leitet.Interference voltages are also further reduced in that the metallic shield is applied in a partially overlapping manner and consists of a band whose surface conducts.
Die Maßnahme, daß zusätzlich eine halbleitende Hülle vorgesehen ist, wirkt sich ebenfalls positiv auf die Unterdrückung von Störspannungen aus. Die halbleitende Schicht kann sowohl unterhalb als auch oberhalb der metallischen Abschirmung vorgesehen werden.The measure that a semiconducting sheath is additionally provided also has a positive effect on the suppression of interference voltages. The semiconducting layer can be provided both below and above the metallic shield.
Dabei wirkt sich günstig aus, wenn die Windungen mit der flächigen halbleitenden Hülle leitend, vorzugsweise flächig, kontaktiert sind.It has a favorable effect if the windings are in contact with the flat semiconducting sheath in a conductive, preferably flat, manner.
Eine weitere Verringerung der Störspannungen erreicht man, wenn zusätzlich eine Abschirmung aus allseitig isoliertem Metallband, mindestens im Bereich der Zuleitung, vorgesehen ist.A further reduction in the interference voltages is achieved if a shield made of metal tape which is insulated on all sides is additionally provided, at least in the area of the supply line.
Die Erfindung wird in einer bevorzugten Ausführungsform unter Bezugnahme auf eine Zeichnung beschrieben, wobei weitere vorteilhafte Einzelheiten den Figuren der Zeichnung zu entnehmen sind. Funktionsmäßig gleiche Teile sind dabei mit denselben Bezugszeichen versehen.The invention is described in a preferred embodiment with reference to a drawing, with further advantageous details being shown in the figures of the drawing. Functionally identical parts are provided with the same reference numerals.
Die Zeichnungen zeigen im einzelnen:
- Fig. 1
- stellt schematisch einen Axialschnitt durch den erfindungsgemäßen Stromwandler dar,
- Fig. 2
- eine axiale Ansicht auf einen Ringkern mit teilweise freigelegter Abschirmung,
- Fig. 3
- ein Detail als Ansicht gemäß Pfeil III in Figur 2 in einem früheren Arbeitsschritt,
- Fig. 4
- stellt die Ansicht gemäß Figur 3 in einem späteren Arbeitsschritt dar und
- Fig. 5
- ein Detail der Zuleitung.
- Fig. 1
- schematically represents an axial section through the current transformer according to the invention,
- Fig. 2
- an axial view of a toroid with partially exposed shield,
- Fig. 3
- 3 shows a detail as a view according to arrow III in FIG. 2 in an earlier work step,
- Fig. 4
- shows the view of Figure 3 in a later step and
- Fig. 5
- a detail of the supply line.
Innerhalb eines rohrförmigen Teils einer Metallkapselung 1 ist ein zylindrisch ausgebildeter Ringkernstromwandler 2 angeordnet. Der Übersichtlichkeit halber ist nur ein Ringkern 3 in Figur 1 dargestellt.A cylindrical toroidal current transformer 2 is arranged within a tubular part of a
Die Ringkerne umgeben einen Hochspannung führenden Leiter 4 und sind gegenüber dem elektrischen Feld durch eine Schirmelektrode 5, 28 abgeschirmt. Die Schirmelektrode 5 weist eine Spalt 6 auf, durch den verhindert wird, daß die Schirmelektrode 5 mit der Metallkapselung 1 eine Kurzschlußwindung um die Ringkern 3 herum bildet, in dem durch den Hochspannungsleiter 4 durchfließenden Strom ein Ringstrom induziert würde. Durch den Spalt 6 gelangen jedoch noch elektrische Störungen in den Bereich der Ringkerne 3.The ring cores surround a
Jeder Ringkern ist von einer in der Figur symbolisch dargestellten Sekundärwicklung 7 umgeben, in der ein von dem Strom im Hochspannungsleiter 4 abhängendes elektrisches Signal durch Induktion erzeugt wird. das elektrische Signal wird durch die Zuleitungen 8, 9 einem Meßanschluß 10 zugeführt.Each toroidal core is surrounded by a secondary winding 7 symbolically represented in the figure, in which an electrical signal dependent on the current in the high-
Die Ringkerne sind von je einer Abschirmung 11 in Form einer Abschirmfolie umgeben, die durch einen schematisch dargestellten Spalt 12 unterbrochen ist, um eine Kurzschlußwicklung zu vermeiden.The ring cores are each surrounded by a
Die Zuleitungen 8, 9 weisen eine metallische Schirmhülle 13 auf, die an ihrem ersten Ende 14 direkt leitend mit der Folie 11 verbunden ist. An ihrem zweiten Ende 15 ist die Schirmhülle 13 im Bereich des Meßanschlusses 10 geerdet. Dabei ist berücksichtigt, daß die Verbindung der Schirmhülle 13 bzw. des Schirmmantels 16 mit dem Erdpotential des Meßanschlusses 10 so gestaltet ist, daß die Zuleitungen 8, 9 auch in diesem Bereich möglichst gut abgeschirmt sind und daß der Erdanschluß der Schirmhülle 13 bzw. des Schirmmantels 16 möglichst kurz gefaßt ist.The feed lines 8, 9 have a
Es ist ein die Schirmhülle 13 umgebender Schirmmantel 16 vorgesehen, der die Zuleitungen 8, 9 und die Schirmhülle 13 umgibt und im Bereich des Meßanschlusses 10 geerdet ist. Hierdurch werden in der Schirmhülle 11 keine Ausgleichsströme induziert. Dies ergibt eine weitere Absenkung der Störspannungspotentiale.A shielding
In Figur 2 ist über den linken unteren Sektor die Abschirmung 11 als meandrierende Wicklung aus Band 17 dargestellt. Diese wird sichtbar, wenn die äußere Bandisolierung 25 und die abdeckende Schutzwicklung 24 (Fig. 4) im genannten Sektor entfernt wird. Die Wicklung wird deutlicher in Figur 3, die eine Ansicht gemäß Pfeil III im Bereich der Zuleitung zeigt. Die Abschirmung 11 besteht aus einem metallischen Band 17, beispielsweise einem metallischen Gewebeband, dessen Oberfläche elastisch leitend ist.In Figure 2, the
Die Wicklung ist meandrierend ausgeführt. Dazu wird Band 17 zunächst mit einer bestimmten Steigung um den üblich aufgebauten Ringkern mit Wicklung und Schutzsicherung gelegt, bis es ein Spaltband 18 erreicht. Es wird unter dem isolierenden Spaltband hindurchgeführt und dann an Kante 19 des Spaltbands 18 in entgegengesetzte Richtung umgelenkt und wieder um den Ringkern geführt, bis es erneut das Spaltband 18 erreicht. Anschließend folgt die nächste Teilwindung wie zuvor beschrieben in entgegengesetzter Richtung. Die einzelnen Windungen 20, 21 haben somit jeweils einen entgegengesetzten Wickelsinn und berühren sich an den Umlenkstellen nicht. Auf diese Weise werden Kurzschlußwindungen vermieden. Das Ende des Bandes wird mit der Schirmhülle 13 der Zuleitungen leitend verbunden. Dabei besteht die Schirmhülle 13 idealerweise aus den Einzelschirmhüllen 22, 23, die jede Zuleitung extra umgeben.The winding is meandering. For this purpose,
Eine weitere Absenkung der Störspannungspotentiale ergibt sich, wenn mindestens im Bereich der Zuleitungen 8, 9 die Abschirmung 11 zusätzlich mit einer Schutzwicklung 24 versehen ist, die beispielsweise aus gegenseitig isolierten Wicklungslagen eines metallisierten Bandes gefertigt ist. Dieses Band kann beispielsweise auf einer Seite mit einer klebenden Schicht und auf der anderen Seite mit einer isolierenden Schicht versehen sein. Die Wicklungen dürfen nicht geschlossen werden, um einen Kurzschlußstrom um den Ringkern herum zu vermeiden.A further lowering of the interference voltage potential results if, at least in the area of the
Abschließend kann dann außen eine Isolierschicht in allgemein bekannter Weise aufgebracht werden. In Figur 4 ist diese zusätzliche Schutzwicklung 24 aus einem mindestens einseitig isolierten metallischen Band dargestellt.Finally, an insulating layer can then be applied on the outside in a generally known manner. In Figure 4, this additional protective winding 24 is shown from a metal tape insulated at least on one side.
In Figur 5 ist in vergrößerter Darstellung das Ende der Zuleitungen gezeigt. Jede Zuleitung 8, 9 weist zunächst eine eigene Einzelschirmhülle 22, 23 auf, die ihrerseits wiederum von der Schirmhülle 13 umgeben sind.The end of the feed lines is shown in an enlarged representation in FIG. Each
In üblicher Weise wird die Sekundärwicklung des Ringkerns 3 zunächst mit einer nicht dargestellten Schutzisolierung versehen, auf der ggf. zusätzlich eine halbleitende weitere Schicht aufgebracht wird. Diese halbleitende Schicht bildet dann die Unterlage 27 (Fig. 4 und 1) für die metallische Abschirmung 11, deren einzelne Windungen flächig auf der halbleitenden Schicht aufgebracht sind und diese leitend berühren.In the usual way, the secondary winding of the toroidal core 3 is first provided with protective insulation (not shown), on which an additional semiconducting layer may also be applied. This semiconducting layer then forms the base 27 (FIGS. 4 and 1) for the
- 11
- MetallkapelMetal chapel
- 22nd
- RingkernstromwandlerToroidal current transformer
- 33rd
- RingkernToroid
- 44th
- Leiterladder
- 55
- SchirmelektrodeShield electrode
- 66
- Spaltgap
- 77
- SekundärwicklungSecondary winding
- 88th
- ZuleitungSupply
- 99
- ZuleitungSupply
- 1010th
- MeßanschlußMeasuring connection
- 1111
- Abschirmungshielding
- 1212th
- Spaltgap
- 1313
- SchirmhülleUmbrella cover
- 1414
- erstes Endefirst end
- 1515
- zweites Endesecond end
- 1616
- SchirmmantelUmbrella coat
- 1717th
- Bandtape
- 1818th
- SpaltbandSlit band
- 1919th
- KanteEdge
- 2020th
- WindungSwirl
- 2121
- WindungSwirl
- 2222
- EinzelschirmhülleSingle screen cover
- 2323
- EinzelschirmhülleSingle screen cover
- 2424th
- SchutzwicklungProtective winding
- 2525th
- BandisolierungTape insulation
- 2727
- Halbleitende UnterlageSemiconductive base
- 2828
- SchirmelektrodeShield electrode
Claims (9)
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE9217807U DE9217807U1 (en) | 1992-12-24 | 1992-12-24 | Toroidal current transformer |
| DE9217807U | 1992-12-24 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0603857A1 true EP0603857A1 (en) | 1994-06-29 |
| EP0603857B1 EP0603857B1 (en) | 1997-09-10 |
Family
ID=6887663
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP93120690A Expired - Lifetime EP0603857B1 (en) | 1992-12-24 | 1993-12-22 | Ring core transformer with parasitic voltage shielding |
Country Status (3)
| Country | Link |
|---|---|
| EP (1) | EP0603857B1 (en) |
| AT (1) | ATE158103T1 (en) |
| DE (2) | DE9217807U1 (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5917316A (en) * | 1996-08-23 | 1999-06-29 | Asea Brown Boveri Ag | Measuring device for a metal-enclosed, gas-insulated high-voltage installation |
| US5939876A (en) * | 1996-08-23 | 1999-08-17 | Asea Brown Boveri Ag | Measuring device for a metal-enclosed, gas-insulated high-voltage installation |
| DE102005007334A1 (en) * | 2005-02-17 | 2006-09-07 | Siemens Ag | Summation current transformer for the universal current-sensitive detection of an electrical differential current |
| EP1693943A3 (en) * | 2005-02-17 | 2015-10-28 | Siemens Aktiengesellschaft | Device for the AC/DC sensitive detection of differential currents |
| CN111354553A (en) * | 2020-03-17 | 2020-06-30 | 浙江宏凯吉科技有限公司 | Open type mutual inductor with shielding structure |
| CN114050041A (en) * | 2021-11-17 | 2022-02-15 | 许昌许继软件技术有限公司 | High-voltage bushing integrated with low-power-consumption current transformer coil |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE4344183A1 (en) * | 1993-12-23 | 1995-06-29 | Ant Nachrichtentech | High voltage transformer and use |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3247383A1 (en) * | 1982-12-10 | 1984-06-14 | BBC Aktiengesellschaft Brown, Boveri & Cie., Baden, Aargau | Current transformer |
| DE3414366A1 (en) * | 1983-09-08 | 1985-03-28 | Sprecher & Schuh AG, Aarau, Aargau | Metal-encapsulated, gas-insulated switching installation |
| EP0165835A1 (en) * | 1984-05-21 | 1985-12-27 | Merlin Gerin | Current sensor with a magnetic core |
| DE4106034A1 (en) * | 1991-02-22 | 1992-08-27 | Siemens Ag | POWER CONVERTER |
-
1992
- 1992-12-24 DE DE9217807U patent/DE9217807U1/en not_active Expired - Lifetime
-
1993
- 1993-12-22 DE DE59307337T patent/DE59307337D1/en not_active Expired - Lifetime
- 1993-12-22 EP EP93120690A patent/EP0603857B1/en not_active Expired - Lifetime
- 1993-12-22 AT AT93120690T patent/ATE158103T1/en not_active IP Right Cessation
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3247383A1 (en) * | 1982-12-10 | 1984-06-14 | BBC Aktiengesellschaft Brown, Boveri & Cie., Baden, Aargau | Current transformer |
| DE3414366A1 (en) * | 1983-09-08 | 1985-03-28 | Sprecher & Schuh AG, Aarau, Aargau | Metal-encapsulated, gas-insulated switching installation |
| EP0165835A1 (en) * | 1984-05-21 | 1985-12-27 | Merlin Gerin | Current sensor with a magnetic core |
| DE4106034A1 (en) * | 1991-02-22 | 1992-08-27 | Siemens Ag | POWER CONVERTER |
Non-Patent Citations (1)
| Title |
|---|
| DATABASE WPI Derwent World Patents Index; * |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5917316A (en) * | 1996-08-23 | 1999-06-29 | Asea Brown Boveri Ag | Measuring device for a metal-enclosed, gas-insulated high-voltage installation |
| US5939876A (en) * | 1996-08-23 | 1999-08-17 | Asea Brown Boveri Ag | Measuring device for a metal-enclosed, gas-insulated high-voltage installation |
| DE102005007334A1 (en) * | 2005-02-17 | 2006-09-07 | Siemens Ag | Summation current transformer for the universal current-sensitive detection of an electrical differential current |
| DE102005007334B4 (en) * | 2005-02-17 | 2007-02-08 | Siemens Ag | Summation current transformer for the universal current-sensitive detection of an electrical differential current |
| EP1696444A3 (en) * | 2005-02-17 | 2009-07-01 | Siemens Aktiengesellschaft | Summation current transformer |
| EP1693943A3 (en) * | 2005-02-17 | 2015-10-28 | Siemens Aktiengesellschaft | Device for the AC/DC sensitive detection of differential currents |
| CN111354553A (en) * | 2020-03-17 | 2020-06-30 | 浙江宏凯吉科技有限公司 | Open type mutual inductor with shielding structure |
| CN114050041A (en) * | 2021-11-17 | 2022-02-15 | 许昌许继软件技术有限公司 | High-voltage bushing integrated with low-power-consumption current transformer coil |
Also Published As
| Publication number | Publication date |
|---|---|
| EP0603857B1 (en) | 1997-09-10 |
| ATE158103T1 (en) | 1997-09-15 |
| DE9217807U1 (en) | 1993-04-08 |
| DE59307337D1 (en) | 1997-10-16 |
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