AU2013231500A1

AU2013231500A1 - Measuring transducer arrangement

Info

Publication number: AU2013231500A1
Application number: AU2013231500A
Authority: AU
Inventors: Stefan Hain; Peter Milewski; Wojciech Olszewski
Original assignee: Siemens AG
Current assignee: Siemens Energy Global GmbH and Co KG
Priority date: 2012-03-16
Filing date: 2013-03-01
Publication date: 2014-09-25
Anticipated expiration: 2033-03-01
Also published as: WO2013135506A1; ES2939733T3; SA113340388B1; EP2810087A1; EP2810087B1; DE102012204179A1; AU2013231500B2; CN104169726A; CN104169726B; RU2014141672A

Abstract

A measuring transducer arrangement has a voltage sensor and a current sensor. The voltage sensor is equipped with a measuring electrode (1a, 1b, 1c) for recording an electric voltage. The current sensor is equipped with a probe (10a, 10b, 10c) for recording an electric current. The measuring electrode (1a, 1b, 1c) is equipped with a receptacle (9a, 9b, 9c), in which the probe (10a, 10b, 10c) of the current sensor is positioned.

Description

PCT/EP2013/054183 - 1 2012PO4775WOAU Description Instrument transformer arrangement The invention relates to an instrument transformer arrangement having a voltage sensor and a current sensor, wherein the voltage sensor has a measuring electrode for detecting an electrical voltage. Such an instrument transformer arrangement is known, for example, from the patent specification CH 682190 A5. The instrument transformer arrangement disclosed therein has a voltage sensor and a current sensor, wherein the voltage sensor has a measuring electrode for detecting an electrical voltage. The current sensor and the voltage sensor are aligned substantially coaxially to one another and are fixed relative to one another via an insulating body. In order to ensure fault-free operation of the current sensor and the voltage sensor, a shielding electrode is provided, via which the current sensor is dielectrically separated from the measuring electrode. In order to arrange the known instrument transformer arrangement in a metal-encapsulated gas-insulated high-voltage assembly, additional shielding electrodes are provided which shield the instrument transformer arrangement. This results in an instrument transformer arrangement which comprises a multiplicity of individual structural components, wherein an angularly rigid composite structure is provided on the interaction of the structural components. In particular, the use of the known instrument transformer arrangement for polyphase-encapsulated switchgear assemblies appears possible only with difficulty since the known arrangement extends on a housing in the form of a ring on the inner lateral surface side around a centrally guided phase conductor.

PCT/EP2013/054183 - 2 2012P04775WOAU The object of the invention is therefore to specify an instrument transformer arrangement which has a simplified design. According to the invention, in the case of an instrument transformer arrangement of the type mentioned at the outset, the object is achieved in that the measuring electrode has a receptacle, in which a probe of the current sensor is positioned. An instrument transformer arrangement is an arrangement which is used for detecting an electrical voltage and/or an electrical current. A voltage can be applied to a phase conductor, for example, and this voltage can be detected by the voltage sensor of the instrument transformer arrangement. Furthermore, the phase conductor can carry an electrical current, driven by the electrical voltage, wherein the electrical current can be detected by the current sensor. Instrument transformer arrangements are used, for example, when a direct voltage and/or current measurement on the phase conductor cannot be performed. This may be the case, for example, when the phase conductor is not very accessible or when the absolute values of the current or voltage are high such that, initially, conversion of the current or the voltage into processable variables needs to take place. Representation of current or voltage can take place, for example, by virtue of a physical variable representing the current or the voltage being detected and converted by means of the current sensor or the voltage sensor. Such detection and conversion can take place, for example, using the transformer principle. However, provision can also be made for a state of charge of the phase conductor to be detected, for example. Thus, for example, a capacitive voltage divider can be constructed using the measuring electrode of the voltage sensor, with the result that a representation of the electrical potential of the phase conductor can be produced. The measuring electrode has an PCT/EP2013/054183 - 3 2012P04775WOAU electrode area acting as capacitor foil, with the result that the measuring electrode carries a floating potential. The representations of the current and/or voltage can be present, for example, in the form of a further-processable measurement signal, for example as a data telegram from the measurement point at which the instrument transformer arrangement is located to a processing point at which evaluation, conversion, display, further-processing, etc. of the measured values produced by the instrument transformer arrangement takes place. Advantageously, provision can be made for the measuring electrode of the voltage sensor to be positioned within an electrical field which surrounds the phase conductor. The phase conductor can be under a high voltage, for example, wherein the high voltage decays along an insulating medium with respect to a, for example, grounded neutral point. The measuring electrode is arranged between the grounded neutral point and the phase conductor, with the result that a capacitive voltage divider can be formed and the charging of the measuring electrode is a representation of a voltage drop occurring at this capacitive voltage divider. The measuring electrode assumes a floating potential. The use of a transformer principle can be provided for the configuration of the current sensor, wherein a phase conductor to be monitored acts as primary winding and the current sensor has a secondary winding. For example, the secondary winding of the current sensor can surround the phase conductor or the phase conductor can pass through the secondary winding. Both the measuring electrode and the current sensor can be positioned with a specific spatial arrangement with respect to one another in respect of the current to be monitored or the voltage to be monitored. With a defined spatial arrangement, reliable measurement of the current and/or the voltage is possible. If the measuring electrode of the voltage sensor is now used for positioning the current sensor, a position of the PCT/EP2013/054183 - 4 2012P04775WOAU measuring electrode of the voltage sensor and the probe of the current sensor is predetermined. The receptacle provides a bearing point for the probe in order to fix the measuring electrode and the probe with respect to one another. For example, the probe can be fixed in a form-fitting manner and/or cohesively to the measuring electrode. The probe can be held in the receptacle. The probe can thus be fixed in terms of its position with respect to the measuring electrode. Unintentional removal of the probe from the measuring electrode is made more difficult. The measuring electrode should have a receptacle in which the probe and the measuring electrode engage in one another. Advantageously, a form-fitting fixing of the probe to the measuring electrode could take place. Various formations of the measuring electrode can be provided as receptacle. The receptacle can have stop points, latching points, etc. The receptacle can also be formed in complementary fashion with respect to a section of the probe, with the result that the probe is connected to the receptacle in a form-fitting manner, for example. Furthermore, provision can advantageously be made for the probe to engage in the electrode in a form-fitting manner, with the result that unintentional movement of the probe away from the measuring electrode is prevented. As an alternative or in addition, the probe can be cohesively connected to the receptacle. Advantageously, the measuring electrode should act as stabilizing element for the probe, with the result that the probe is supported on the measuring electrode. The measuring electrode has, for example, an angularly rigid form, which also assists dimensional stability of the probe, for example. A winding of the probe can extend at least partially through the receptacle, for example, with the result that the position of the winding on the measuring electrode is fixed. For example, winding limits can be arranged on the measuring electrode, wherein a winding of the current sensor extends between the winding limits. A winding can extend in the form of a loop through the receptacle, for example. In addition to using a transformer principle, the current sensor PCT/EP2013/054183 - 5 2012P04775WOAU can also be in the form of a so-called optical current sensor, for example, i.e. the probe can also have a winding with an optical waveguide, for example, which conducts polarized light. Owing to the effect of a magnetic field of a current flowing through a phase conductor, the polarization plane of the polarized light can be altered, wherein a change in the angle of the polarization plane can be proportional to the absolute value of the current to be monitored. In addition to a use of windings which are arranged on the measuring electrode, the use of Hall probes can also be provided, for example, which Hall probes are supported and positioned on the measuring electrode. Furthermore, further probe types can also be positioned on the receptacle of the measuring electrode. A further advantageous configuration can provide for the probe to be dielectrically shielded at least partially by the measuring electrode. The measuring electrode has an electrode area, which is aligned in the direction of the phase conductor to be monitored. The electrode area acts as a capacitive foil for forming a capacitive voltage divider. Correspondingly, the measuring electrode, in particular the electrode area, carries a floating potential. In the shadow of the probe, a space which is dielectrically shielded by the measuring electrode or the electrode area thereof is produced opposite the phase conductor to be monitored. The measuring electrode or the electrode area can in this case have a curved profile around one or more axes, with the result that, firstly, a sufficient electrode area is provided for the voltage sensor and, secondly, improved shielding of the shielded space is provided. Correspondingly, in the case of an arrangement of the probe of the current sensor within this dielectrically shielded space, it is possible to dispense with separate shielding electrodes. The PCT/EP2013/054183 - 6 2012PO4775WOAU measuring electrode required for the voltage measurement can provide a capacitive foil in order to represent a capacitive voltage divider. Furthermore, by virtue of the dielectric properties of the measuring electrode, a field-free space can be provided at least sectionally. A part of the probe, which is at risk of partial discharge, for example, can now extend within this space. Advantageously, the majority of the probe can also extend within this dielectrically shielded space, with the result that it is possible to dispense with additional, separate shielding devices for the probe. The field-free space preferably extends on a side of the measuring electrode which is remote from the phase conductor. A further advantageous configuration can provide for the receptacle to be in the form of a cutout in the measuring electrode. A cutout in the measuring electrode provides an enlarged space for receiving the probe of the current sensor. The dielectrically shielded space can be shielded by the cutout not only from a single direction. For this purpose, the cutout can provide lateral (dielectrically shielding) walls, which intensify the dielectrically shielding effect of the cutout. The electrode area should preferably also extend up to the lateral walls in order to have a dielectrically shielding effect there as well. The cutout can extend, for example, in the form of a pocket into the measuring electrode. Provision can also be made for the cutout to extend in the form of a slot-shaped groove in the measuring electrode. Slot cheeks or groove cheeks can firstly form part of the receptacle. Secondly, slot cheeks or groove cheeks can act as lateral wall. In this case, the wall thickness should be designed in particular in respect of the mechanically bearing properties of the measuring electrode since only a specific potential should be carried so as to form a capacitive foil on the measuring electrode, which specific potential can also be realized on a PCT/EP2013/054183 - 7 2012P04775WOAU flat-extending electrically active measuring electrode layer with a small wall thickness. For example, the measuring electrode can have an electrically insulating bearing body, which has only thin-walled coatings for forming a capacitive foil/the electrode area. A further advantageous configuration can provide for the measuring electrode to be in the form of a ring and for the receptacle to be arranged on the outer lateral surface side on the measuring electrode. A phase conductor can advantageously pass through a ring-shaped measuring electrode, with the result that a ring-shaped electrode area of the measuring electrode areas the phase conductor. This ring-shaped area on the inner lateral surface side acts as capacitive foil/electrode area for forming a capacitive voltage divider. The area on the inner lateral surface side can also be curved transversely to the ring, in addition to a curvature in the circumferential direction of said ring. Thus, the area can correspond to a segment of a surface of a toroid, for example, wherein the toroid can have any desired profile. It is advantageous if the cutout extends on the outer lateral surface side on the measuring electrode, with the result that the area facing the phase conductor is constantly shaped continuously without any projections, independently of the shape or presence of a cutout in the measuring electrode. The measuring electrode should preferably be shaped so as to run continuously peripherally in the form of a ring. However, provision can also be made for the measuring electrode to merely be in the form of a sector of a ring surrounding a phase conductor. For example, such a ring sector can face the phase conductor on the inner lateral surface side and have the cutout in an area on the outer lateral surface side. Depending on the configuration of the probe of the current sensor, the shape of the receptacle can be configured PCT/EP2013/054183 - 8 2012PO4775WOAU variably. A ring-shaped measuring electrode can be profiled variously, for example substantially in the form of a U. Furthermore, it may be advantageous for the cutout to have an in particular continuously peripheral groove. A cutout in the form of a groove has the advantage that a cutout is formed in the measuring electrode, which cutout extends into a wall of the measuring electrode. The groove can in particular be formed so as to be continuously peripheral on the measuring electrode. This provides, in a simple manner, a possibility of allowing windings with a plurality of turns to pass through the groove, for example. The groove can be formed into the measuring electrode in the form of a slot, for example. Correspondingly, a field-free space can be formed within the slot-shaped groove, which field-free space is dielectrically shielded by the base and the cheeks of the groove. For this purpose, the measuring electrode can be formed from an electrically conductive material. Alternatively, an electrically conductive coating can also be provided on the measuring electrode in order to ensure dielectric shielding and to form a capacitive foil. It is advantageous to fill the groove as fully as possible with the probe, with the result that sections which are as large as possible, in particular the entire probe, are/is arranged within the field shadow formed in the groove. The groove can have correspondingly configured profiles in order to achieve filling of the groove with the probe in a simple manner, in particular in form-complementary fashion. In the case of an arrangement of the groove on the outer lateral surface side in a ring-shaped measuring electrode, a cutout is thus produced which is accessible from all radial directions in the direction of the ring center and thus enables filling or winding of a winding, for example, of the probe on the measuring electrode.

PCT/EP2013/054183 - 9 2012P04775WOAU A further advantageous configuration can provide for the ring shaped measuring electrode to have a substantially U-shaped profile. A ring-shaped measuring electrode with a substantially U-shaped profile has the advantage that the wall has a virtually constant wall thickness over the extent of the profile. Thus, firstly a low-mass measuring electrode can be formed. Secondly, the angular rigidity of the measuring electrode can be increased owing to the U-shaped profile. This results in an in particular ring-shaped measuring electrode, which is shaped in the manner of a wheel rim, wherein a rim well acts as a cutout in the form of a groove and rim flanges (slot cheeks/groove cheeks) close off the U-shaped profile. The wall thickness of the measuring electrode should remain approximately constant over the extent of the U-shaped profile, wherein the profile can also be provided such that a reduced wall thickness is provided, for example, towards the free ends of the profile of the measuring electrode. The profile can be substantially in the form of a circular ring, for example. However, elliptical cross-sectional forms can also be used. Furthermore, provision can advantageously be made for the measuring electrode and the probe to be embedded in an insulating body. Embedding the measuring electrode and the probe in an insulating body makes it possible to fix the probe and the measuring electrode relative to one another. In particular when the probe is borne by the measuring electrode, the position of the probe and the measuring electrode with respect to one another is already fixed prior to the measuring electrode and the probe being embedded in an insulating body. Embedding in an insulating body secures the position of the measuring electrode and the probe with respect to one another. Provision can be made, for example, for it to be possible for the probe of the PCT/EP2013/054183 - 10 2012PO4775WOAU current sensor to already be laid in the receptacle of the measuring electrode prior to the embedding of said measuring electrode and then for it to be surrounded and enclosed by a liquid insulating material, with the result that, after curing, a solid insulating body is provided, which holds together the measuring probe and the measuring electrode in undetachable fashion. The insulating body can thus adhesively bond and crosslink (cohesive bond) the probe and the measuring electrode. Furthermore, provision can advantageously be made for a substantially radially aligned connecting lug to be arranged on the ring-shaped measuring electrode. In order to make contact with the measuring electrode and to be able to tap off its potential, it is advantageous to provide a connecting lug on the measuring electrode. In particular when using a ring-shaped measuring electrode, the connecting lug should extend away from the ring or the ring segment in the radial direction. For example, the measuring electrode can be attached at the outer circumference to a free area of the measuring electrode. For example, in the case of a measuring electrode with a U-shaped profile, the connecting lug can be attached to a limb of the U profile and protrude freely away from the limb. In the case of a ring-shaped electrode, the connecting lug should in this case be aligned radially. The connecting lug carries the same electrical potential as the electrode area of the measuring electrode. Contact can be made with the electrode area via the connecting lug. Advantageously, provision can furthermore be made for the connecting lug to be aligned with a cavity arranged in the insulating body. The connecting lug is, for example, an electrically conductive body which carries the potential of the measuring electrode and PCT/EP2013/054183 - 11 2012PO4775WOAU with which, for its part, contact can be made in order to be able to transmit the potential of the measuring electrode. The connecting lug can open out in a cavity or protrude into a cavity. For this purpose, the connecting lug can be aligned with a cavity, in which a plug-type connection, a screw connection, a contact terminal, a connecting line, etc. is arranged, for example, in order to be able to transmit the potential of the connecting lug via connecting lines, for example. In addition to making electrical contact with the measuring electrode via the connecting lug, the connecting lug can also represent an anti-rotation means in an insulating body receiving the measuring electrode. For example, a rotation, shifting, tilting of the measuring electrode within the insulating body is thus prevented. The cavity can be used within the insulating body in order to receive connecting elements such as plug-type cable connectors, terminal boxes, solder lugs, etc. Thus, an electrical signal can be tapped off by the measuring electrode or the probe, whose connecting lines can also open out in the cavity, for example, and transmitted via transmission paths from the insulating body using connecting lines. A further advantageous configuration can provide for the cavity to be surrounded by a fitting. A fitting can be, for example, a molding which is cast into the insulating body or is encapsulated by casting during casting of the insulating body, with the result that the molding delimits a cavity in the manner of stay-in-place formwork within the insulating body. The fitting can be constructed, for example, from electrically conductive materials, for example cast aluminum, or electrically insulating materials, for example polyethylene. The use of an electrically conductive material has the advantage that the cavity is dielectrically shielded. A mechanical connection to other structural components can be produced via the fitting.

PCT/EP2013/054183 - 12 2012PO4775WOAU A further advantageous configuration can provide for a phase conductor, which passes through the ring-shaped measuring electrode, to be surrounded by a shielding electrode. A measuring electrode serves to monitor a state of a phase conductor in respect of its electrical voltage. A ring-shaped measuring electrode can in this case surround the phase conductor and said phase conductor can pass through said measuring electrode. In the region in which the phase conductor is surrounded by the measuring electrode, provision can be made for the use of a shielding electrode, which for its part surrounds the phase conductor and is in turn surrounded by the measuring electrode. Thus, a defined space between the shielding electrode and the measuring electrode can be formed, in which, independently of the shape of the phase conductor, an electrical field propagates between the shielding electrode and the measuring electrode. It is thus possible, for example, for the electrical potential of the phase conductor to be transmitted to the shielding electrode, wherein an electrical field is applied to the dielectric arranged between the shielding electrode and the measuring electrode in a defined manner within a geometrically predetermined scope, as a result of which the measuring electrode assumes a specific electrical potential. Correspondingly, the measurement accuracy of the voltage sensor having the measuring electrode can be improved. For example, a cylindrical capacitor is formed between the shielding electrode and the measuring electrode. The shielding electrode can be connected in fluid-tight fashion to the phase conductor, for example. For example, the shielding electrode and the phase conductor can be welded to one another. Alternatively, the shielding electrode and the phase conductor can be integrally connected to one another.

PCT/EP2013/054183 - 13 2012PO4775WOAU A further advantageous configuration can provide for the shielding electrode and/or the phase conductor to pass through the insulating body in fluid-tight fashion. The phase conductor, which is embedded in the insulating body, passes through the insulating body such that electrical contact can be made with the phase conductor on both sides of the insulating body. Advantageously, the measuring electrode should be surrounded completely on the lateral surface side and on the end side by insulating material of the insulating body, with the result that mechanical interference or any influence on the measuring electrode or the probe is prevented by the insulating body. Correspondingly, the phase conductor can be inserted into the insulating body in fluid-tight fashion. For example, the phase conductor can be encapsulated by the insulating material being cast around it in fluid-tight fashion. Furthermore, provision can also be made for the shielding electrode itself to be inserted into the insulating body in fluid-tight fashion, with the result that the insulating body is also capable of forming a fluid-tight barrier with a phase conductor which passes through the insulating body. In particular, it is advantageous if both the phase conductor and the shielding electrode are connected to one another in fluid tight fashion, with the result that a fluid-tight composite structure comprising the shielding electrode, the insulating body and the phase conductor is provided. Furthermore, provision can advantageously be made for a plurality of measuring electrodes and a plurality of probes to be embedded in an insulating body. In addition to a configuration of a coaxial arrangement, on which a phase conductor is arranged centrally, which phase conductor is surrounded coaxially by a measuring electrode and an insulating body, the arrangement of a plurality of phase PCT/EP2013/054183 - 14 2012PO4775WOAU conductors in one and the same insulating body can furthermore also be provided, wherein in each case one measuring electrode, in particular also in each case one probe, is associated with each of the phase conductors. It is thus possible to position a plurality of phase conductors via a common insulating body and to also be able to perform electrical monitoring of each individual phase conductor when positioning the plurality of phase conductors with respect to one another. For this purpose, the insulating body can be formed integrally or in more than one piece. For example, a measuring electrode can be cast with a phase conductor and a probe, and this semifinished structural component is then cast with further preferably identical semifinished structural components in a further casting process to give a common insulating body, with the result that the resulting insulating body comprises a plurality of parts which are connected to one another in fluid-tight fashion. Correspondingly, a disk-shaped insulating body is produced, in which a plurality of measuring electrodes are embedded and through which a plurality of phase conductors pass in fluid tight fashion. A further advantageous configuration can provide for the insulating body to be surrounded on the lateral surface side by a reinforcing frame. A reinforcing frame surrounds the insulating body on the outer lateral surface side, with the result that the insulating body is mechanically protected. The reinforcing frame can run continuously peripherally, for example. In particular, the reinforcing frame should be kept free of edges and corners. In particular, a substantially ring-shaped reinforcing frame which receives a substantially circular-cylindrical insulating body in its interior is suitable. Via the reinforcing frame, it is possible to position, transport, fit, etc. the insulating body in addition to measuring electrode(s) or probe(s) located therein.

PCT/EP2013/054183 - 15 2012PO4775WOAU A further advantageous configuration can provide for the insulating body to be a post insulator of the phase conductor(s). In addition to its electrically insulating properties, the insulating body also has mechanical properties, with the result that a phase conductor can be positioned with- a fixed location via the insulating body itself. In particular when using a reinforcing frame, it is possible to flange-connect the instrument transformer arrangement to a flange, for example, or to position the phase conductor(s) with respect to the flange. Therefore, the phase conductor(s) is/are fixed locally. Electrical insulation of each phase conductor is ensured via the insulating body. A further advantageous configuration can provide for the insulating body to be part of a fluid-tight barrier of an encapsulating housing. An instrument transformer arrangement can advantageously be arranged on an electrical energy transmission device. An electrical energy transmission device has a series of phase conductors, which carry an electrical current, driven by an electrical voltage. In order to insulate the phase conductors, the use of an electrically insulating fluid, in particular an electrically insulating gas, can be provided. In order to prevent evaporation of the electrically insulating fluid, the electrically insulating fluid can be enclosed in an encapsulating housing. The electrically insulating fluid can be placed under elevated pressure within this encapsulating housing, with the result that the dielectric strength of the electrically insulating fluid is additionally increased. Examples of electrically insulating fluids that can be used are insulating oils or insulating gases, such as sulfur hexafluoride, nitrogen or mixtures with these gases. The phase PCT/EP2013/054183 - 16 2012P04775WOAU conductors preferably need to be routed so as to be spaced apart from the encapsulating housings or passed through the encapsulating housings in electrically insulated fashion. The insulating body can correspondingly be used as part of a barrier on an encapsulating housing in order to introduce a phase conductor into an encapsulating housing filled with an electrically insulating fluid. The encapsulating housing can be configured as a pressure vessel, for example, with the result that it can withstand a differential pressure between the interior of the encapsulating housing and the surrounding environment of the encapsulating housing. An exemplary embodiment of the invention will be shown schematically in a drawing and described in more detail below. In the drawing: Figure 1 shows a perspective view of a partially cut-away instrument transformer arrangement, Figure 2 shows a cross section through the instrument transformer arrangement in detail, and Figure 3 shows a section through an instrument transformer arrangement in the installed state. Figure 1 shows a perspective view of an instrument transformer arrangement. In this case, the instrument transformer arrangement has a three-phase design, i.e. the instrument transformer arrangement has a voltage sensor, which has a first electrode, a second electrode and a third electrode la, 1b, 1c, which is used for voltage monitoring of a first phase conductor 2a, a second phase conductor 2b and a third phase conductor 2c. Each of the phase conductors 2a, 2b, 2c is surrounded by one of the ring-shaped measuring electrodes la, 1b, 1c.

PCT/EP2013/054183 - 17 2012PO4775WOAU The three phase conductors 2a, 2b, 2c serve to transmit an electrical current in each case. In order to drive an electrical current through each of the three phase conductors 2a, 2b, 2c, a corresponding electrical voltage is applied to each of the phase conductors 2a, 2b, 2c. In a three-phase variant embodiment, as shown in figure 1, the transmission of a polyphase AC voltage electrical energy system is preferably provided, with the result that three currents flow through the phase conductors 2a, 2b, 2c, with these three currents each having differing instantaneous absolute values and different phase angles in the case of the presence of driving AC voltages. As a deviation from the three-phase variant configuration shown in figure 1, however, the invention can also be used in a single-phase embodiment. In this case, the use of a single phase conductor is envisaged instead of the use of three phase conductors 2a, 2b, 2c, wherein the correspondingly associated component parts are only provided with respect to the single phase conductor. The three phase conductors 2a, 2b, 2c have a substantially cylindrical configuration, wherein the phase conductors 2a, 2b, 2c in this case have a circular cross section. The cylinder axes of the phase conductors 2a, 2b, 2c are aligned approximately parallel to one another, wherein, in a plan view of the cylinder axes of the phase conductors 2a, 2b, 2c, the cylinder axes are arranged so as to be spaced apart from one another and define the corner points of an equilateral triangle. The cylinder axes lie parallel to a main axis 3, which lies within the triangle formed between the phase conductors 2a, 2b, 2c. The three phase conductors 2a, 2b, 2c are embedded in an insulating body 12. Figure 1 does not show the insulating body 12. The insulating body 12 is in the form of a disk and is PCT/EP2013/054183 - 18 2012PO4775WOAU surrounded on the outer lateral surface side by a reinforcing frame 4. The reinforcing frame 4 is in this case in the form of a circular ring, wherein the reinforcing frame 4 is aligned coaxially to the main axis 3. The insulating body 12 has been cut away in figure 1, with the result that the interior design of the structural components embedded within the insulating body 12 can be seen. The three phase conductors 2a, 2b, 2c pass through the insulating body 12 in such a way that the phase conductors 2a, 2b, 2c pass through and protrude beyond end sides of the insulating body 12. It is thus possible for electrical contact to be made with the phase conductors 2a, 2b, 2c on both sides of the end sides of the insulating body 12. The phase conductors 2a, 2b, 2c should be inserted into the insulating body 12 in a manner which is as fluid-tight as possible. For simplified incorporation of the phase conductors 2a, 2b, 2c, the insulating body 12 has openings, through which the phase conductors 2a, 2b, 2c pass. In order to enable improved operation of the instrument transformer arrangement, the phase conductors 2a, 2b, 2c are each surrounded by shielding electrodes 5a, 5b, 5c. The shielding electrodes 5a, 5b, 5c each carry the electrical potential of the associated first phase conductor 2a, second phase conductor 2b or third phase conductor 2c. The shielding electrodes 5a, 5b, 5c are electrically conductively connected to the respective phase conductors 2a, 2b, 2c. The shielding electrodes 5a, 5b, 5c surround the respective phase conductors 2a, 2b, 2c in each case on the outer lateral surface side. The shielding electrodes 5a, 5b, 5c are each configured so as to be hollow cylindrical, wherein the end sides are rounded off in order to give a dielectrically favorable contour. The phase conductors 2a, 2b, 2c are preferably connected to the respectively associated shielding electrodes 5a, 5b, 5c in fluid-tight fashion, wherein the shielding electrodes 5a, 5b, 5c are each connected in fluid-tight fashion to the insulating body 12. It is thus possible to form a fluid-tight barrier between the phase conductors 2a, 2b, 2c, the shielding electrodes 5a, 5b, PCT/EP2013/054183 - 19 2012PO4775WOAU 5c and the insulating body 12. In addition to a configuration of the shielding electrode 5a, 5b, 5c as discrete component parts, a corresponding shape of the phase conductors 2a, 2b, 2c with an integral form can be provided. Each of the phase conductors 2a, 2b, 2c is surrounded by in each case one measuring electrode la, 1b, 1c on the outer lateral surface side. In this case, the measuring electrodes la, 1b, 1c are in the form of a ring and are arranged coaxially to the respective phase conductor 2a, 2b, 2c. The position of the shielding electrodes 5a, 5b, 5c with respect to the measuring electrodes la, 1b, 1c is in this case selected such that the shielding electrodes 5a, 5b, 5c have a greater spatial extent in the direction of the main axis 3 or the cylinder axes than the respectively associated measuring electrode la, lb, 1c. The respective measuring electrode la, 1b, 1c faces the respective shielding electrode 5a, 5b, 5c on the inner lateral surface side. The shielding electrodes 5a, 5b, 5c each carry the electrical potential of the respectively associated phase conductor 2a, 2b, 2c. The measuring electrodes la, 1b, 1c are arranged so as to be electrically insulated with respect to the respectively surrounded phase conductors 2a, 2b, 2c and with respect to the further phase conductors 2a, 2b, 2c. Likewise, the measuring electrodes la, 1b, ic are arranged so as to be electrically insulated from one another. In order to fix the measuring electrodes la, 1b, 1c and the phase conductors 2a, 2b, 2c spatially with respect to one another, these structural components are embedded in the insulating body 12. The insulating body 12 itself is substantially in the form of a disk and is surrounded by the reinforcing frame 4 on the outer lateral surface side. The insulating body 12 can be formed integrally, for example. However, provision can also be made for the insulating body 12 to be formed in more than one piece, with the result that, for example, a semifinished structural component has a first part of the insulating body 12, wherein PCT/EP2013/054183 - 20 2012P04775WOAU one or more further parts of the insulating body 12 supplement the first part to form a disk-shaped insulating body 12. The measuring electrodes la, 1b, 1c each have a connecting lug 6a, Gb, 6c on their outer circumference. A connecting lug Ga, 6b, 6c carries the electrical potential of the measuring electrode la, lb, 1c bearing said connecting lug in each case. A measuring electrode la, 1b, ic can be manufactured, for example, from an electrically conductive material, for example copper, aluminum, electrically conductive polymer, etc. The potential of the respective measuring electrode la, 1b, 1c can be transmitted into a cavity within the insulating body 12 by means of the connecting lug 6a, 6b, 6c. In this case, a cavity is associated with each phase conductor 2a, 2b, 2c. The cavities within the insulating body 12 are each surrounded by a fitting 7a, 7b, 7c. The fittings 7a, 7b, 7c each surround a cavity, which adjoins, in aligned fashion, the radially aligned connecting lugs 6a, 6b, 6c of the respective measuring electrode la, 1b, 1c. It is possible for measuring lines 8a, 8b to be routed within the cavities surrounded by the fittings 7a, 7b, 7c in order to make contact with the respective measuring electrode la, 1b, 1c, for example. The fittings 7a, 7b, 7c are inserted into the disk-shaped insulating body 12 cohesively and surround the cavities which lead, in the radial direction, to a lateral surface on the outer circumference of the insulating body 12. There, in each case one radially aligned cutout is provided within the reinforcing frame 4 in aligned fashion, with it being possible for connecting lines 8a, 8b to be passed to the outside through said cutout. The measuring electrodes la, 1b, 1c each have an identical configuration. The measuring electrodes la, 1b, 1c are in the form of rings, wherein the material and dimensions are selected such that the measuring electrodes la, 1b, 1c themselves are designed to be torsionally rigid. The measuring electrodes la, 1b, 1c are each provided with a receptacle in the form of a PCT/EP2013/054183 - 21 2012P04775WOAU cutout 9a, 9b, 9c on the outer lateral surface side. The cutouts 9a, 9b, 9c are in this case introduced into the measuring electrodes la, lb, 1c in the manner of a continuously peripheral groove. In this case, the groove has a bent profile, for example in the form of a segment of a circle or a segment of an ellipse. Preferably, the profile of the measuring electrodes la, 1b, 1c can be selected to be U-shaped, wherein the profile should be configured with rounded corners. A peripheral slot is formed in an outer lateral surface of the measuring electrodes la, 1b, 1c by virtue of the cutout 9a, 9b, 9c. Given corresponding profiling with a profile which is U shaped, for example semicircular or in the form of an ellipsoidal ring, a measuring electrode la, 1b, 1c in the manner of a wheel rim is thus produced, wherein the cutout 9a, 9b, 9c is formed between the rim flanges. Preferably, the measuring electrode la, 1b, 1c can have an approximately uniform wall thickness in profile, for example. The cutouts 9a, 9b, 9c are dielectrically shielded at least partially by the capacitive foils/the electrode areas of the measuring electrodes la, 1b, 1c. Receptacles are formed by the cutouts 9a, 9b, 9c, into which receptacles in each case one probe 10a, 10b, 10c of a current sensor can be inserted. The probes 10a, 10b, 10c can each have a semiconductor group, for example, which semiconductor groups are each inserted into the field shadow of those regions of the measuring electrodes la, 1b, 1c which are dielectrically shielded in the cutouts 9a, 9b, 9c. Such probes 10a, 10b, 10c can include Hall probes, for example. Furthermore, the cutouts 9a, 9b, 9c can also serve to receive in each case one winding. A winding can have, for example, an optical fiber which is positioned on the respective measuring electrode la, 1b, 1c so as to run peripherally around the cutout 9a, 9b, 9c at least singularly, in particular multiply, so as to form a plurality of loops. It is thus possible to direct polarized light into the region of the respectively surrounded phase conductor la, PCT/EP2013/054183 - 22 2012P04775WOAU lb, 1c, wherein the polarization plane of the polarized light is deflected away depending on a resultant magnetic field of the current flowing through the respective phase conductor la, lb, 1c. Furthermore, the probe can also have a transformer winding, which surrounds the respective phase conductor la, 1b, 1c lying in the respective cutout 9a, 9b, 9c. A particularly advantageous configuration can be provided in that the probes 10a, 10b, 10c each have a Rogowski coil, wherein the Rogowski coils are each formed in mirror-inverted fashion with respect to the shape of the cutouts 9a, 9b, 9c, with the result that the Rogowski coils can be inserted flush into the cutouts 9a, 9b, 9c. The Rogowski coils are thus located in the dielectric field shadow of the respective measuring electrode la, 1b, 1c. In this case, a Rogowski coil can be arranged completely within the field shadow of the respective cutout 9a, 9b, 9c. However, provision can also be made for only parts of the Rogowski coils located in the respective cutout 9a, 9b, 9c to be dielectrically shielded. Thus, for example, a Rogowski coil can protrude out of the cutout 9a, 9b, 9c for example in the cutout 9a, 9b, 9c which opens on the outer lateral surface side. For example, a Rogowski coil can be circular in cross section, wherein this circular configuration engages in form complementary fashion in the cross-sectional configuration of the associated cutout 9a, 9b, 9c. Contact can be made with the windings, in particular the Rogowski coils, of the probes 10a, 10b, 10c via the cavities which are arranged within the fittings 7a, 7b, 7c in the insulating body 12. Correspondingly, connecting lines 8a, 8b can be passed out of the interior of the insulating body 12 from the probes 10a, 10b, 10c of the current sensor. Figure 2 shows, by way of example, the first measuring electrode la and the first phase conductor 2a and the further structural components associated directly with the first phase conductor 2a or the first measuring electrode la, in section. The second measuring electrode lb and the third measuring PCT/EP2013/054183 - 23 2012PO4775WOAU electrode ic as well as the second phase conductor 2b and the third phase conductor 2c and the further structural components associated with these further measuring electrodes 1b, 1c and further phase conductors 2b, 2c are formed identically to the construction shown by way of example in figure 2. Figure 2 shows a section, with the main axis 3 lying in the section plane thereof. Correspondingly, the reinforcing frame 4 is shown in sectional profile. The first phase conductor 2a is likewise sectioned. The way in which the associated shielding electrode 5a surrounds the first phase conductor 2a on the outer lateral surface side is shown. The associated shielding electrode 5a is for its part surrounded on the outer lateral surface side by the associated first measuring electrode la. The first measuring electrode la emerges from the section plane and the continous ring-shaped structure of the first measuring electrode la is shown. The first measuring electrode la has, in profile, a U-shaped form, which is substantially in the form of a semicircular ring. The cutout 9a formed is filled with a probe 10a surrounding the measuring electrode la on the outer lateral surface side. The probe 10a has a substantially circular cross section, which is designed to be mirror-inverted with respect to the profile of the cutout 9a. The probe 10a runs peripherally around the first measuring electrode la on the outer lateral surface side. The position of a connecting lug 6a, which protrudes in the radial direction, in relation to the central axis of rotation of the measuring electrode la in the radial direction in the direction of an inner lateral surface of the reinforcing frame 4, is illustrated by way of example on one of the limbs, formed in profile and delimiting the cutout, of the first measuring electrode la. The connecting lug 6a protrudes as far as a base of a cavity 11 of the insulating body 12. The cavity 11 is delimited by a fitting 7a, which extends at least partially as far as into the insulating body 12. The fitting 7a is PCT/EP2013/054183 - 24 2012PO4775WOAU substantially rotationally symmetrical and hollow-cylindrical and is connected to the reinforcing frame 4 in angularly rigid fashion, for example by means of a screw connection, at its end facing the reinforcing frame 4. A cutout is provided in the reinforcing frame in the region of the connection between the fitting 7a and the reinforcing frame 4 in order to introduce connecting lines 8a, 8b into the cavity 11 from the reinforcing frame 4 on the outer lateral surface side. A connecting line 8a can firstly be connected to the probe 10a of the first phase conductor 2a of the current sensor. Secondly, contact can be made with the first measuring electrode la via a connecting line 8b. For this purpose, the connecting line 8b is connected to the connecting lug 6a. The connecting lug Ga is arranged on the measuring electrode la in the region at which the measuring electrode la has the smallest distance from the inner lateral surface of the reinforcing frame 4. In figure 2, the insulating body 12 comprises a plurality of subelements, by way of example. Thus, provision is made in accordance with the configuration shown in figure 2 for first an angularly rigid connection between the first phase conductor 2a, the associated shielding electrode 5a and the first measuring electrode la, which surrounds the first phase conductor 2a, to be formed. Correspondingly, a first part of the insulating body 12 which is substantially in the form of a circular disk is formed, in which first part the first measuring electrode la is embedded. The first measuring electrode la is embedded with the associated probe 10a completely within the insulating body 12, in particular completely within the first part of the insulating body 12. The first measuring electrode la has a holding tab 13, which enables form-fitting fixing within the insulating body 12. In order to produce an instrument transformer arrangement, provision can be made for the insulating body 12 to first be cast in liquid form for embedding the first measuring electrode la in addition to the probe 10a and the first phase conductor PCT/EP2013/054183 - 25 2012PO4775WOAU 2a and the associated shielding electrode 5a. After curing of the insulating material, the semifinished phase conductors 2a, 2b, 2c are positioned within the reinforcing frame 4, whereupon they are completely encapsulated by casting with a further insulating material, with the result that the insulating body 12 has a plurality of subelements which are cast independently of one another. The dimensions can in this case be selected such that subelements of the insulating body 12 are completely encased with insulating material by virtue of terminating encapsulating casting. In any case, however, end sides of the phase conductors 2a, 2b, 2c should protrude out of the insulating body 12. Provision can be made for likewise the shielding electrodes 5a, 5b, 5c to protrude out of the insulating body 12 on end sides. If required, the wall thickness of the insulating body 12 can vary. For example, provision can also be made for the insulating body 12 to have substantially the same wall thickness as the reinforcing frame, with the result that the fittings 7a, 7b, 7c are also completely encased by the insulating body 12, in the same way as the shielding electrodes 5a, 5b, 5c. Independently of the type of manufacture of the insulating body 12, the end sides of the insulating body 12 should be free from butt joints in the insulating material. The insulating body 12 can also be formed integrally, i.e. all of the component parts surrounded by the insulating body 12 are encased with insulating material which has not yet cured in a single casting process. After curing, an angularly rigid insulating body 12 is produced which positions the embedded component parts in a fixed location and for its part lies within the reinforcing frame 4 in a fixed location. Figure 3 shows a section through an instrument transformer arrangement in the installed state. The reinforcing frame 4 is arranged between a first ring flange 14a and a second ring flange 14b. The two ring flanges 14a, 14b are bolted to one PCT/EP2013/054183 - 26 2012P04775WOAU another with the reinforcing frame 4 interposed. The bolts can protrude through cutouts, for example, which are arranged in the reinforcing frame 4, with the result that a force-fitting and form-fitting composite structure is provided between the ring flanges 14a, 14b and the reinforcing frame 4. By way of example, figure 3 shows the use of an insulating body 12a which has approximately the same width as the reinforcing frame 4. In section, the shielding electrode Sa, which surrounds the first phase conductor 2a, and the first measuring electrode la, which surrounds the first phase conductor 2a and which for its part receives a probe 10a of the current sensor in a cutout 9a, are shown symbolically. The thickness of the insulating body 12 is in this case selected such that, apart from the phase conductors 2a, 2c which protrude beyond the insulating body 12a at the end side, further elements are arranged within the insulating body 12a. Access to the elements located in the interior of the insulating body 12a is enabled via the cavity 11, which is located in the insulating body 12a and for its part opens out in a cutout in the reinforcing frame 4. Via this access point, connecting lines 8a, 8b for the current sensor and the voltage sensor are accessible. The first and the second ring flanges 14a, 14b are connected to a first encapsulating housing 15a and a second encapsulating housing 15b. The two encapsulating housings 15a, 15b are substantially tubular, wherein a receiving volume is provided in the interior, in which the phase conductors 2a, 2c are arranged. The two encapsulating housings 15a, 15b have a fluid tight configuration, with the result that the interior can be filled with an electrically insulating fluid. The electrically insulating fluid can in this case be placed under elevated pressure so as to increase the dielectric strength, with the result that the encapsulating housings 15a, 15b are pressure vessels. The phase conductors 2a, 2c are supported on the encapsulating housings 15a, 15b in electrically insulated fashion. Electrically insulated holding of the phase conductors PCT/EP2013/054183 - 27 2012P04775WOAU 2a, 2c is provided in this case via the insulating body 12a of the instrument transformer arrangement. It is thus possible for the first and second encapsulating housings 15a, 15b to be designed to be electrically conductive and for ground potential to be applied to the encapsulating housings 15a, 15b, for example. An insulating gap within the encapsulating housings 15a, 15b between the phase conductors 2a, 2c with respect to one another and the phase conductors 2a, 2c with respect to the encapsulating housings 15a, 15b is provided by the electrically insulating fluid. In this case, the instrument transformer arrangement is designed in such a way that a fluid-tight barrier is provided between the two volumes of the first and second encapsulating housings 15a, 15b via the insulating body 12, i.e. the emergence of an electrically insulating fluid from the region surrounded by the first encapsulating housing 15a into the region surrounded by the second encapsulating housing 15b is prevented by the instrument transformer arrangement la with its insulating body 12a. Correspondingly, the insulating body 12 represents part of a pressure-tight barrier, which is fluid-tight, on an encapsulating housing 15a, 15b. Correspondingly, fluid-tight embedding and routing of the phase conductors 2a, 2c through the insulating body 12a is provided. However, provision can also be made for overflow channels to be provided in the insulating body 12 or in the instrument transformer arrangement, via which overflow channels an insulating fluid can flow over from the first into the second encapsulating housing 15a, 15b, and vice versa. The encapsulating housings 15a, 15b are, for example, part of a fluid-insulated electrical energy transmission device, which is referred to as "gas-insulated" in the event of the use of an electrical insulating gas. An electrical current can be driven by phase conductors 2a, 2b, 2c by means of a gas-insulated electrical energy transmission device, with the result that transmission of electrical energy between two points is enabled.

PCT/EP2013/054183 - 28 2012PO4775WOAU When using the measuring electrodes 9a, 9b, 9c, a capacitance foil is provided between the respectively associated phase conductors 2a, 2b, 2c and the surrounding environment of the phase conductors 2a, 2b, 2c in particular with respect to one of the encapsulating housings 15a, 15b or with respect to the reinforcing frame 4. Thus, a capacitive voltage divider is preferably provided between the potential of the respective phase conductor 2a, 2b, 2c and ground potential. Correspondingly, charging of the electrically insulating measuring electrodes la, 1b, 1c is provided. The potential of the measuring electrodes la, 1b, 1c can be passed out of the instrument transformer arrangement via a measuring line 8b. The information on the potential of the measuring electrode la, 1b, 1c can be further-processed and a conclusion drawn on the potential of the respective phase conductor 2a, 2b, 2c. When using the probes 10a, 10b, 10c, which are each inserted into a cutout 9a, 9b, 9c in the respectively associated measuring electrode la, 1b, 1c, it is possible, for example, using the transformer principle, to represent an electrical current flow through the respectively associated phase conductor 2a, 2b, 2c. A signal output by the probe 10a, 10b can be transported on via a connecting line 8, 8a. The information regarding a monitored electrical current which is provided by the current sensor and in respect of a monitored electrical voltage which is provided by the voltage sensor can now be used further or further-processed.

Claims

1. An instrument transformer arrangement having a voltage sensor and a current sensor, wherein the voltage sensor has a measuring electrode (la, 1b, 1c) for detecting an electrical voltage, characterized in that the measuring electrode (la, 1b, 1c) has a receptacle (9a, 9b, 9c), in which a probe (10a, 10b, 10c) of the current sensor is positioned.

2. The instrument transformer arrangement as claimed in claim 1, characterized in that the probe (10a, 10b, 10c) is dielectrically shielded at least partially by the measuring electrode (la, 1b, 1c).

3. The instrument transformer arrangement as claimed in claim 1 or 2, characterized in that the receptacle (9a, 9b, 9c) is formed as a cutout (9a, 9b, 9c) in the measuring electrode (la, lb, 1c).

4. The instrument transformer arrangement as claimed in claim 3, characterized in that the measuring electrode (la, 1b, 1c) is in the form of a ring and the receptacle (9a, 9b, 9c) is arranged on the outer lateral surface side on the measuring electrode (la, 1b, 1c).

5. The instrument transformer arrangement as claimed in either of claims 2 and 4, characterized in that the cutout (9a, 9b, 9c) has an in particular continuously peripheral groove. PCT/EP2013/054183 - 30 2012PO4775WOAU

6. The instrument transformer arrangement as claimed in either of claims 4 and 5, characterized in that the ring-shaped measuring electrode (la, lb, lc) has a substantially U-shaped profile.

7. The instrument transformer arrangement as claimed in one of claims 1 to 6, characterized in that the measuring electrode (la, lb, lc) and the probe (10a, lob, 10c) are embedded in an insulating body (12, 12a).

8. The instrument transformer arrangement as claimed in one of claims 4 to 7, characterized in that a substantially radially aligned connecting lug (6a, 6b, 6c) is arranged on the ring-shaped measuring electrode (la, lb, 1c).

9. The instrument transformer arrangement as claimed in claim 8, characterized in that the connecting lug (6a, 6b, 6c) is aligned with a cavity (11) arranged in the insulating body (12, 12a).

10. The instrument transformer arrangement as claimed in claim 9, characterized in that the cavity (11) is surrounded by a fitting (7a, 7b, 7c).

11. The instrument transformer arrangement as claimed in one of claims 4 to 10, characterized in that a phase conductor (2a, 2b, 2c), which passes through the ring shaped measuring electrode (la, lb, 1c), is surrounded by a shielding electrode (5a, 5b, Sc). PCT/EP2013/054183 - 31 2012PO4775WOAU

12. The instrument transformer arrangement as claimed in claim 11, characterized in that the shielding electrode (5a, 5b, 5c) and/or the phase conductor (2a, 2b, 2c) passes through the insulating body (12, 12a) in fluid-tight fashion.

13. The instrument transformer arrangement as claimed in one of claims 1 to 12, characterized in that a plurality of measuring electrodes (la, 1b, 1c) and a plurality of probes (10a, 10b, 10c) are embedded in an insulating body (12, 12a).

14. The instrument transformer arrangement as claimed in claims 7 to 13, characterized in that the insulating body (12, 12a) is surrounded on the lateral surface side by a reinforcing frame (4).

15. The instrument transformer arrangement as claimed in claims 7 to 14, characterized in that the insulating body (12, 12a) is a post insulator of the phase conductor(s) (2a, 2b, 2c).

16. The instrument transformer arrangement as claimed in one of claims 7 to 15, characterized in that the insulating body (12, 12a) is part of a fluid-tight barrier of an encapsulated housing (15a, 15b).