Sensing device and corresponding transmission line

Abstract

The invention relates to a sensing device and a corresponding transmission line, and provides a sensing device comprising: a capacitive voltage sensor comprising a substrate, a reference plate and a sensing plate, each of which is cylindrical and coaxial with respect to a main axis of the sensing device, the reference plate being arranged on a radially outer side of the substrate, the sensing plate being concentrically arranged on a radially inner side of the substrate, the reference plate and the sensing plate are made of a conductive material, the substrate is made of an electrically insulating material, and the voltage sensor outputs a voltage signal representing a voltage value between the reference plate and the sensing plate; and a Rogowski coil current sensor including a main plate centered on the main axis and made of an electrically insulating material and a Rogowski coil carried by the main plate, the current sensor outputting a signal representative of a current flowing through the conductor surrounded by the Rogowski coil. The current sensor is arranged concentrically around the voltage sensor and secures a reference plate attached to the voltage sensor, thereby forming a one-piece construction of the sensing device comprising the current sensor directly supported on the voltage sensor.

Description

Technical Field

[0001] This invention relates to a sensing device comprising a capacitive voltage sensor and a Rogowski coil current sensor, and a transmission line comprising such a sensing device. In preferred applications, the invention can be used in power distribution systems, and more specifically in gas-insulated switchgear. Background Technology

[0002] Gas-insulated switchgear (GIS) is an electrical device used for controlling and protecting high-voltage (HV) and medium-voltage (MV) systems, and for distributing power within these systems. GIS consists of metal-enclosed compartments housing various components, including circuit breakers, disconnectors, busbars, current and voltage transformers, grounding switches, surge protectors, etc. These components are enclosed within a sealed metal enclosure filled with an insulating gas, typically sulfur hexafluoride (SF6) or a newer generation of climate-friendly high-dielectric gas. 3 It is a mixture of C4-FN (C4-fluoronitrile), CO2 and O2.

[0003] Accurate real-time current and voltage signals are required to control the operational status of the power grid connected through HV substations (including GIS). Precise current and voltage measurements are particularly needed in GIS to operate circuit breakers and / or disconnectors in case of errors in the connected power grid, and for billing purposes to allow for accurate billing of energy delivered to the grid. For this purpose, GIS includes voltage transformers and current transformers.

[0004] So-called low-power instrument transformers (LPITs) have been proposed to provide accurate measurements of voltage, current, and power flow directly from the main conductors that transmit electrical energy. Compared to conventional transformers, LPITs are compact and lightweight, and offer improved efficiency, safety, and communication capabilities.

[0005] For example, "Optimized LPIT (Low Power InstrumentTransformer) applications in GIS using SF6 and climate-friendly insulating gasg" by Reto Christen et al. 3 (Conference materials, CIGRE Conference 2022, Paris, France) The use of LPIT in GIS was studied. The main sensor for current measurement used therein is an unsaturated Rogowski coil on a printed circuit board (PCB) located outside the gas compartment of the GIS. Voltage measurement uses a capacitive voltage divider, which is concentrically arranged around the high-voltage master body inside the gas compartment of the GIS.

[0006] EP3276363A1 discloses a sensing device comprising a CEVT-based voltage sensor and a RECT-based current sensor. The voltage sensor includes a reference plate and a sensing plate, both of which are annular, concentric, and spaced apart. The inner surface of the reference plate faces the outer surface of the sensing plate. Each of the reference plate and the sensing plate is made of a conductive material, and the voltage sensor is adapted to output a voltage signal representing the voltage value between the reference plate and the sensing plate. The RECT-based current sensor includes a toroidal Rogowski coil and is adapted to output a signal representing the current flowing through a conductor surrounded by the Rogowski coil.

[0007] A transmission line is also disclosed, comprising a grounding tube, one or more main conductors disposed within the grounding tube, and a sensing device including a RECT current sensor and a CEVT voltage sensor, each disposed around a corresponding main conductor. A housing is molded around the voltage and current sensors and serves as a protective shield to reduce electromagnetic interference that could cause errors in current measurements using Rogowski coils.

[0008] The entire assembly, including the current sensor, the voltage sensor, and the molded housing in which additional components are mounted, can be quite large, bulky, difficult to manufacture and assemble, and costly. There is a need to provide a sensing device that includes a RECT current sensor and a CEVT voltage sensor, which is more compact, lighter, easier to manufacture and assemble, and cheaper.

[0009] WO2012 / 072558A1 discloses a Rogowski coil sensor, comprising: a main board made of an electrically insulating material, the main board being annular in shape centered on the main axis of the sensor and extending radially in a plane relative to the main axis of the sensor; an annular Rogowski coil carried by the main board; and a protective shield surrounding the main board. The Rogowski coil includes windings made of a conductive material and includes a plurality of winding arms covering two radially extending end faces of the main board and extending radially relative to the main axis of the sensor; and a metallized aperture through the main board. The metallized aperture connects the winding arms located on one side of the main board to winding arms located on the other side of the main board. The protective shield includes two sub-plates arranged axially on both sides of the main board, wherein each sub-plate has a metal layer facing the windings on one of the end faces of the main board. The protective shield protects the winding arms of the Rogowski coil from damage and shields the Rogowski coil from external electric fields. The winding arms can be formed by printing or depositing conductive material on the end faces of the main board.

[0010] Such Rogowski coil current sensors applicable to GIS can have very large radial and axial dimensions and require a significant amount of space. For example, the outer diameter of the current sensor can exceed 500 mm, or even 1200 mm in some applications, requiring a correspondingly large housing and enclosure. In a three-phase configuration, each main phase is equipped with its own combination of a Rogowski coil current sensor and a capacitive voltage sensor. This can result in a very large footprint and assembly space for GIS or any component including such sensing devices. This footprint and assembly space may not always be available. A reduction in footprint and assembly space is desirable.

[0011] The purpose of this invention is to provide a sensing device comprising a CEVT-based voltage sensor and a RECT-based current sensor, which is more compact, lighter, easier to manufacture, and easier to assemble than known sensing devices. The sensing device should provide accurate real-time current and voltage measurements and should be suitable for a variety of applications, particularly for GIS in HV or MV substations.

[0012] Another object of the present invention is to provide a transmission line including such sensing devices, particularly a GIS transmission line, designed to reduce the required floor space and assembly space. Summary of the Invention

[0013] These objectives are achieved by a sensing device having the features of independent claim 1 and a transmission line having the features of another independent claim 15.

[0014] According to one aspect of the invention, a sensing device is provided, comprising a capacitive voltage sensor and a Rogowski coil current sensor. The voltage sensor includes a substrate, a reference plate, and a sensing plate, wherein the substrate, reference plate, and sensing plate are each cylindrical and coaxial with respect to the main axis of the sensing device. The reference plate is arranged radially outward on the substrate, and the sensing plate is spaced apart from the reference plate and concentrically arranged radially inward on the substrate. The reference plate and sensing plate are each made of a conductive material, and the substrate is made of an electrically insulating material. The voltage sensor is adapted to output a voltage signal representing the voltage value between the reference plate and the sensing plate. The current sensor includes a toroidal main plate centered on the main axis and made of an electrically insulating material, and a toroidal Rogowski coil carried by the main plate. The Rogowski coil includes a winding made of a conductive material and including a plurality of winding arms arranged on a radially extending end face of the main plate and spaced apart from each other in a circumferential direction and extending radially relative to the main axis; and a metallized via passing through the main plate and electrically connecting a winding arm located on one end face of the main plate to a winding arm located on the other end face of the main plate. The current sensor is adapted to output a signal representing the current flowing through a conductor surrounded by a Rogowski coil. The current sensor is arranged concentrically around the voltage sensor and fixedly attached to the reference plate of the voltage sensor, thereby forming an integral construction of a sensing device including a current sensor directly supported on the voltage sensor.

[0015] This invention provides a low-power instrument transformer (LPIT) device comprising a current sensor based on a Rohler effect current transformer (RECT) and a voltage sensor based on a capacitive effect voltage transformer (CEVT), designed and assembled to form an integrated sensing device, wherein the voltage sensor and the current sensor are located in the same location and mechanically connected to each other, such that the current sensor is directly carried by the voltage sensor. This results in a cost-effective, less cumbersome, and less expensive construction that requires fewer parts for assembly and installation, and is easier to manufacture and assemble than known sensing devices. The sensing device is arranged to provide reliable and accurate voltage and current measurements and is suitable for a variety of applications, including gas-insulated switchgear (GIS) in high-voltage (HV) and medium-voltage (MV) substations.

[0016] In a preferred embodiment of the sensing device, the substrate of the voltage sensor can be a flexible circuit board, and the reference board and sensing board can be metal strips printed on the flexible circuit board. This can be implemented easily and cost-effectively. This design offers advantages such as long-term stability, no partial discharge, extremely high thermal stability, and resistance to conductor vibration (e.g., the high-pressure conductor in the gas compartment of a GIS, around which the sensing device is arranged).

[0017] Flexible circuit boards can advantageously be made of flame-retardant epoxy materials, preferably glass-reinforced epoxy laminates, such as FR-4. FR-4 is a composite material made of woven glass fiber cloth and epoxy resin adhesive, which is flame-retardant and self-extinguishing when exposed to heat or open flame. This property makes FR-4 particularly suitable for electronic devices and printed circuit boards, and especially for GIS in HF and MV substations (where high flame retardancy is particularly important). In any case, flexible circuit board materials (such as FR-4) also provide high mechanical strength and high electrical insulation quality under both dry and wet conditions.

[0018] In a preferred embodiment of any of the above-described sensing devices, the main board of the current sensor may be a flexible circuit board, and the winding arms of the Rogowski coil may be conductive traces printed on the end face of the flexible circuit board. Printing may include any technique known in the art, such as directly printing or depositing conductive material on the end face of the main board, or covering the end face of the main board with a uniform layer of conductive material and then removing a portion of the conductive material using a mask and acid, leaving only the portion of conductive material forming the winding arms. The Rogowski coil may be designed as an unsaturated Rogowski coil, providing the desired distortion-free and hysteresis-free output signal, which is a voltage proportional to the first derivative of the main current flowing through the dominant conductor (e.g., the high-voltage conductor of the GIS of the sensing device). The non-magnetic material of the printed circuit board is fundamental to providing a reliable and predictable Rogowski coil current sensor with high winding uniformity, which, for example, allows good resistance to external electric fields from currents in adjacent phases.

[0019] Advantageously, the flexible circuit board of the motherboard can be made of flame-retardant epoxy material, more preferably glass-reinforced epoxy laminate, such as FR-4, which can provide the benefits already mentioned above related to the flexible circuit board material of the voltage sensor substrate.

[0020] In any of the aforementioned sensing devices, the reference plate and sensing plate may be made of copper or aluminum, and / or the winding arms and metallized vias may be made of copper or aluminum. Copper is particularly preferred when the reference plate, sensing plate, and winding arms are formed as conductive planes or conductive traces printed on a flexible circuit board. Copper planes and copper traces can be printed or etched onto the substrate to form the desired circuit pattern. Depending on the specific application and requirements, other suitable conductive materials, such as gold and silver, may also be used.

[0021] In a particularly preferred embodiment of the sensing device, the substrate of the voltage sensor and the main board of the current sensor are made of the same flexible circuit board material, particularly flame-retardant epoxy, preferably FR-4, and the reference board, sensing board, and Rogowski coil windings are all made of the same metallic material, particularly copper or other metallic materials suitable for printing onto the flexible circuit board. Therefore, both sensors are based on the same materials and can be easily and cost-effectively manufactured and assembled into a single unit, reducing the number of components and materials, and using the same technology to produce the printed circuit board. Compared to known sensing devices, the resulting sensing device is very compact, lightweight, and relatively inexpensive, and allows for easy integral integration within a GIS enclosure with a short axial length and small radial width. Furthermore, using the same materials results in similar thermal expansion and contraction characteristics for the voltage and current sensors under different environmental and operating conditions.

[0022] In any of the aforementioned sensing devices, the current sensor is preferably soldered to the reference plate of the voltage sensor. Soldering is easy and cost-effective to implement and provides a stable and long-lasting mechanical bond between the current sensor and the voltage sensor.

[0023] In any of the aforementioned sensing devices, the current sensor may further include a metallic protective shield arranged to protect the main board and the windings of the Rogowski coil from potential damage (e.g., due to mechanical exposure), and to shield the Rogowski coil from external electric fields. The protective shield may include a protective plate arranged axially on both sides of the main board, extending parallel to the main board and coaxial with the main axis of the sensing device. The protective plate protects the winding arms of the Rogowski coil from impacts and other external hazards, and also protects the Rogowski coil from electromagnetic interference that could impair accurate current measurement.

[0024] Preferably, the metal protective shield can be arranged to substantially surround the entire motherboard and the winding of the Rogowski coil, i.e., covering both the radially extending end face of the motherboard and both the radially inner and outer sides. The term "substantially surround" here means that spaces, through holes, etc., may exist on one or more sides of the motherboard to allow, for example, connecting wires to pass through.

[0025] In a particularly preferred embodiment, a portion of the reference plate forms the radially inner portion of the metallic protective shield and is arranged to shield the Rogowski coil from the sensing plate. The reference plate of the voltage sensor is located radially outer of the voltage sensor and grounded, and thus blocks electric field lines extending from or into the sensing plate. Given the reference plate, no additional shielding is required for the Rogowski coil located radially inner of the current sensor. The reference plate and other portions of the protective shield can be combined to provide protection for the Rogowski coil against electric fields from any direction.

[0026] In embodiments of the sensing device that include a protective shield, the protective plate can be soldered to the reference plate at the interface between the radially inner portion of the protective plate and the reference plate using conductive solder. This provides the required stable mechanical connection and a closed and continuous protective shield that essentially surrounds the entire circumference of the current sensor. The protective shield can be grounded, and therefore the reference plate is also grounded via solder connection.

[0027] In some embodiments of the sensing device of the last mentioned type, which includes a protective plate soldered to a reference plate, a portion of the metallic material of the protective plate may be omitted or removed from the radially inner interface portion of the protective plate before soldering the protective plate to the reference plate. This reduces the conductivity at the interface between the protective plate and the reference plate, thereby reducing heat input during the soldering process. This provides some protection to the Rogowski coil from heat damage during the soldering process.

[0028] Any of the aforementioned sensing devices may further include at least one temperature sensor attached to a current sensor at a predetermined location and configured to measure the temperature within a corresponding predetermined volume relative to the current sensor and voltage sensor. The measurement signals provided by the temperature sensors(s) allow for correction of the sensed current and voltage values ​​to compensate for the effects of temperature fluctuations on the sensor geometry, i.e., the thermal expansion and contraction of the components of the sensing device. The behavior of printed circuit board materials with temperature is generally well-known, and compensation for thermal expansion and contraction and / or temperature-dependent resistance changes can be readily implemented. This provides a basis for stable and accurate voltage and current measurements with excellent precision and linearity under varying conditions.

[0029] In some embodiments, any of the above-described sensing devices may include two RECT-based current sensors attached to a voltage sensor and positioned around a single main body, wherein the two current sensors are axially stacked and supported against each other while being substantially insulated from each other. The two current sensors may be electrically connected to each other in series or in parallel. A series connection provides greater sensitivity and a reduced radial size to the resulting combined current sensor. A parallel connection of the current sensors provides redundancy to enhance the safety and reliability of current measurements.

[0030] According to another aspect of the invention, a transmission line, particularly a transmission line for a gas-insulated switchgear (GIS), is provided. The transmission line includes a grounding conduit made of a conductive material defining an internal cavity filled with a dielectric gas for insulation and protection; one or more conductors arranged within the cavity of the grounding conduit and made of a conductive material, wherein the grounding conduit and each conductor extend along the same longitudinal axis, and each conductor is spaced apart from the grounding conduit; and a sensing device of any of the aforementioned types assigned to each of the one or more conductors, wherein the sensing device is arranged around the corresponding conductor between the grounding conduit and the corresponding conductor within the dielectric gas-filled internal cavity.

[0031] The entire sensing device, including a combination of a CEVT-based voltage sensor and a RECT-based current sensor, is located in a dielectric gas (e.g., SF6 or preferably g). 3 Alternatively, it can be housed within another insulating gas for insulation and protection within the internal cavity of the transmission tube. For example, in conventional low-power instrument transformers, only the voltage sensor is placed within the gas compartment of the GIS, while the current sensor is located outside the gas compartment to ensure reliable, accurate, and interference-free current measurement. It has been found that the entire integrated sensing device can be located within the gas compartment without compromising the reliability and accuracy of the current measurement or the safety of the components.

[0032] In other aspects, the sensing device in the transmission line may have any embodiment and benefit from any embodiment of the sensing device mentioned above in relation to the first aspect of the invention. To avoid repetition, reference is made to the description of the sensing device mentioned above.

[0033] The transmission line may further include a computer device electrically connected to the sensing device, configured to calculate the conductor-to-conductor voltage value between the grounding tube and the corresponding conductor using the output voltage signal provided by the voltage sensor, based on the principle of a capacitive voltage divider, and to calculate the current value flowing through the conductor by integrating the output signal provided by the current sensor. The computer device may be further configured to use a sensed temperature signal provided by a corresponding temperature sensor (if available) to correct the measured conductor-to-conductor voltage and current measurements to compensate for the effects of temperature fluctuations on the geometry and characteristics of the sensor components.

[0034] Technical solution 1. A sensing device (17), comprising:

[0035] A capacitive voltage sensor (21) includes a substrate (33), a reference plate (34), and a sensing plate (36). Each of the substrate (33), the reference plate (34), and the sensing plate (36) is cylindrical and coaxial with respect to the main axis (A) of the sensing device (17). The reference plate (34) is arranged on the radially outer side (35a) of the substrate (33), and the sensing plate (36) is spaced apart from the reference plate (34) and concentrically arranged on the radially inner side (35b) of the substrate (33). The reference plate (34) and the sensing plate (36) are each made of a conductive material, and the substrate (33) is made of an electrically insulating material. The voltage sensor (21) is adapted to output a voltage signal representing the voltage value between the reference plate (34) and the sensing plate (36).

[0036] A Rogowski coil current sensor (22) includes a toroidal main plate (39) centered on the main axis (A) and made of electrically insulating material, and a ring-shaped Rogowski coil (41) carried by the main plate (39). The Rogowski coil (41) includes a winding (42) made of conductive material and comprising a plurality of winding arms (43) arranged on radially extending end faces (44a, 44b) of the main plate (39) and extending along... The circumferential directions are spaced apart from each other and extend radially relative to the main axis (A); and the metallized hole (46) passes through the main board (39) and electrically connects the winding arm (43) located on one end face (44a) of the main board (39) to the winding arm (43) located on the other end face (44b) of the main board (39), the current sensor (22) being adapted to output a signal representing the current flowing through the conductor (16) surrounded by the Rogowski coil (41);

[0037] The current sensor (22) is arranged concentrically around the voltage sensor (21) and fixedly attached to the reference plate (34) of the voltage sensor (21), thereby forming an integral structure of the sensing device (17) including the current sensor (22) directly supported on the voltage sensor (21).

[0038] Technical Solution 2. The sensing device (17) according to Technical Solution 1 is characterized in that the substrate (33) of the voltage sensor (21) is a flexible circuit board, and the reference plate (34) and the sensing plate (36) are metal strips printed on the flexible circuit board.

[0039] Technical Solution 3. The sensing device (17) according to Technical Solution 2 is characterized in that the flexible circuit board is made of flame-retardant epoxy material, preferably glass-reinforced epoxy laminate material, especially FR-4.

[0040] Technical Solution 4. The sensing device (17) according to any one of the foregoing technical solutions is characterized in that the main board (39) of the current sensor (22) is a flexible circuit board, and the winding arm (43) of the Rogowski coil (41) is a conductive trace printed on the end face (44a, 44b) of the flexible circuit board.

[0041] Technical Solution 5. The sensing device (17) according to Technical Solution 4 is characterized in that the flexible circuit board is made of flame-retardant epoxy material, preferably glass-reinforced epoxy laminate material, especially FR-4.

[0042] Technical Solution 6. The sensing device (17) according to any one of the foregoing technical solutions is characterized in that the reference plate (34) and the sensing plate (36) are made of copper or aluminum, and wherein the winding arm (43) and the metallized hole (46) are made of copper or aluminum.

[0043] Technical Solution 7. The sensing device (17) according to any one of the foregoing technical solutions is characterized in that the substrate (33) of the voltage sensor (21) and the main board (39) of the current sensor (22) are made of the same flexible circuit board material, and the reference board (34), the sensing board (36) and the winding (42) of the Rogowski coil (41) are made of the same metal material.

[0044] Technical Solution 8. The sensing device (17) according to any one of the foregoing technical solutions is characterized in that the current sensor (21) is soldered to the reference plate (34) of the voltage sensor (21).

[0045] Technical Solution 9. The sensing device (17) according to any one of the foregoing technical solutions is characterized in that the current sensor (21) further includes a metal protective shield (47) arranged to protect the main board (39) and the winding (42) of the Rogowski coil (41) from possible damage, and to shield the Rogowski coil (41) from the influence of an external electric field, wherein the protective shield (47) includes protective plates (48a, 48b) arranged axially on both sides of the main board (39) to be parallel to the main board (39) and coaxial with the main axis (A) of the sensing device (17).

[0046] Technical Solution 10. The sensing device (17) according to Technical Solution 9 is characterized in that the metal protective shield (47) is arranged substantially around the main board (39) and the winding (42) of the Rogowski coil (41), wherein a portion (53) of the reference plate (34) forms a radially inner portion (56) of the metal protective shield (47) and is arranged to shield the Rogowski coil (41) from the sensing plate (36).

[0047] Technical Solution 11. The sensing device (17) according to Technical Solution 10 is characterized in that the protection plate (48a, 48b) is soldered to the reference plate (34) using conductive solder.

[0048] Technical Solution 12. The sensing device (17) according to Technical Solution 11 is characterized in that, before the protective plate (48a, 48b) is soldered to the reference plate (34), a portion of the metal material of the protective plate (48a, 48b) is omitted or removed from the radially inner portion (57) of the protective plate (48a, 48b) to reduce the conductivity at the interface between the protective plate (48a, 48b) and the reference plate (34) in order to reduce the heat input during the soldering process.

[0049] Technical Solution 13. The sensing device (17) according to any one of the foregoing technical solutions is characterized in that the sensing device (17) further includes at least one temperature sensor (61), the at least one temperature sensor (61) being attached to the current sensor (2) at a predetermined position and configured to measure the temperature in a corresponding predetermined volume relative to the current sensor (22) and the voltage sensor (21).

[0050] Technical Solution 14. The sensing device (17) according to any one of the foregoing technical solutions is characterized in that the sensing device (17) includes two current sensors (22) that are axially stacked and supported against each other, and the two current sensors (22) are electrically connected to each other in series or in parallel.

[0051] Technical Solution 15. A transmission line (6), particularly a transmission line (6) of a gas-insulated switchgear (1), comprising:

[0052] A grounding tube (18) made of conductive material defines an internal cavity (19) filled with a dielectric gas;

[0053] One or more conductors (16) are arranged in an internal cavity (19) within the grounding conduit (18) and are made of the conductive material, the grounding conduit (18) and each conductor (16) extending along the same longitudinal axis (A), each conductor (16) being spaced apart from the grounding conduit (18); and

[0054] A sensing device (17) according to any one of the foregoing technical solutions is assigned to each of the one or more conductors (16), the sensing device (17) being arranged around the corresponding conductor (16) between the grounding tube (18) and the corresponding conductor (16) in the internal cavity (19) filled with the dielectric material.

[0055] These and other advantages and features of the invention will become more apparent from the following description taken in conjunction with the accompanying drawings. Attached Figure Description

[0056] The subject matter of the invention is specifically pointed out and explicitly claimed in the claims at the end of the specification. The foregoing and other features and advantages of the invention become clear from the following detailed description, together with the accompanying drawings, in which:

[0057] Figure 1 This is a partial cross-sectional schematic diagram of a gas-insulated switchgear, illustrating a preferred environment in which the present invention can be used;

[0058] Figure 2 It can be used Figure 1 A simplified view of the cross-section of the transmission line in a gas-insulated switchgear and including a sensing device according to an embodiment of the invention;

[0059] Figure 3 It shows Figure 2 The magnified section I, for a simplified view, shows details of the sensing device of the present invention, which includes a Rogowski coil current sensor and a capacitive voltage sensor.

[0060] Figure 4 yes Figure 2 and Figure 3 A schematic axial plan view of the sensing device is shown, and the structure of the Rogowski coil current sensor according to an embodiment is illustrated.

[0061] Figure 5 It is along Figure 4 Cross-section of the Rogowski coil current sensor in line II-II;

[0062] Figure 6 Is with Figure 5 A cross-section similar to the cross-section of the image illustrates a sensing device including a Rogowski coil current sensor according to another embodiment of the invention; and

[0063] Figure 7 It is a schematic cross-section of a three-phase embodiment of a transmission line according to an embodiment of the present invention, located in a plane orthogonal to the longitudinal axis. Detailed Implementation

[0064] Figure 1 A gas-insulated switchgear (GIS) 1 is shown to illustrate a preferred environment in which the invention can be used. In the illustrated embodiment, the GIS 1 comprises a busbar unit 2, a circuit breaker unit 3, a line-side unit 4, and an instrumented transmission line 6 connecting the circuit breaker unit 3 to the line-side unit 4. Units 2-4 and the transmission line 6 are constructed of metal-enclosed compartments that house the respective components and utilize a gas (such as SF6 or preferably a more climate-friendly gas g). 3 (or other insulating gases or gas mixtures) serve as the primary insulation between the live part and the grounded metal enclosure. The insulating gas provides high dielectric strength, high thermal stability, and good arc-extinguishing performance.

[0065] exist Figure 1 In an exemplary embodiment, bus unit 2 includes two bus sub-units 7, each bus sub-unit including three-phase bus conductors 8a, 8b, and 8c. Bus conductors 8a-c are connected to generators, transformers, feeders, etc., which can form a first power grid (not shown herein). Figure 1 (Left side of the diagram). Bus conductors 8a-c are connected to circuit breaker unit 3 via disconnector 9 and grounding switch 11 (shown schematically only here). If necessary, disconnector 9 is arranged to isolate a portion of the circuit from the rest of the system for maintenance or testing purposes. Grounding switch 11 can ground a portion of the circuit for safety or grounding purposes. Control box 5 is located on top of bus unit 2 for controlling the operation of its components.

[0066] Circuit breaker unit 3 includes several circuit breakers 13, corresponding to the number of phases and bus conductors 8a-c in the system. For convenience, only one circuit breaker is shown herein. The circuit breakers 13 are arranged to interrupt the flow of current in the event of a fault. A circuit breaker operating mechanism 14 is provided for operating the circuit breaker 13 as needed. In this exemplary embodiment, the circuit breaker operating mechanism 14 is positioned above the transmission line 6 in the space between the circuit breaker unit 3 and the line-side unit 4, but it can be arranged at any desired location.

[0067] The line-side unit 4 of GIS1 mainly includes an integrated cable interface 15, and the subsequent power grid (not shown in this article, in...) Figure 1 The power transmission cable (on the right side) can be connected to the integrated cable interface 15 to transmit power there. For safety purposes, the line-side unit 4 may further include other components such as grounding switches, surge arresters, etc.

[0068] Transmission line 6 is located between circuit breaker unit 3 and line-side unit 4, and includes several main conductors 16 corresponding to the number of phases in the system. For convenience, only one main conductor 16 is shown herein. The main conductor 16 connects the corresponding conductors (not individually labeled) in circuit breaker unit 3 (which are connected to bus connectors 8a, 8b, 8c) to cable interfaces 15 in line-side unit 4 to allow current to flow through them.

[0069] Under normal conditions, the contacts of circuit breaker 13 are closed, and current flows through them and through the main conductor 16 and cable interface 15 to the connected power grid, and vice versa. When a fault such as a short circuit or overload occurs in the circuit, the contacts of circuit breaker 13 separate, and an electric arc is generated between the contacts. The arc generates heat and pressure, which can damage the contacts and other components, and must be extinguished as quickly as possible. GIS1 provides arc extinguishing through a mechanism of thermal interruption and dielectric interruption.

[0070] It is necessary to measure the amounts of current, voltage, and power transmitted between power grids connected to each other via high-voltage (HV) or medium-voltage (MV) substations, including GIS1. In the event of an error in the connected power grid, accurate current and voltage measurements are required to operate circuit breaker 13. Accurate current and voltage measurements can also be used for billing purposes to allow for accurate billing of energy transmitted to or between power grids. For this purpose, transmission line 6 is equipped with sensing device 17, which is arranged to provide accurate real-time current and voltage measurement signals associated with the power flowing through the main conductor 16. The following is in conjunction with… Figures 2 to 7 The sensing device 17 of the present invention will be described in more detail.

[0071] It should be noted that the sensing device 17 of the present invention is in Figure 1 The circuit breaker unit 3 is shown as being included in the transmission line 6 that connects the line-side unit 4 of the GIS1 to the circuit breaker unit 3. However, the transmission line 6 with the sensing device 17 can be located anywhere within the GIS1. The GIS1 must not have Figure 1 The configuration shown herein. Numerous GIS configurations known in the art and applicable herein include components (e.g., busbar units and circuit breaker units) positioned adjacent to each other in the horizontal direction, or one on top of another in the vertical direction, wherein other components may be arranged in corresponding units 2-4 and / or additional units, and the components may be associated with… Figure 1 The different arrangements shown are illustrated. The sensing device 17 of the present invention is not necessarily applicable to gas-insulated switchgear, but can be used in a wide variety of power transmission applications.

[0072] Now go to Figures 2 to 7The diagram illustrates a transmission line 6 including a sensing device 17 according to an embodiment of the invention, in a schematic cross-sectional view. The transmission line 6 includes one or more main conductors 16 (only one shown, hereinafter referred to as conductor 16), a grounding conduit 18 surrounding the conductor 16, and the sensing device 17. The conductor 16 is configured to transmit current from a first end of the transmission line 6 to a second end of the transmission line 6.

[0073] The grounding tube 18 is made of a conductive material, particularly a metal or metal alloy, and defines an internal cavity 19 filled with a dielectric gas for insulation and protection. The dielectric gas is preferably g. 3 Alternatively, it could be SF6. Transmission line 6 can be part of a gas-insulated switchgear (GIS), such as... Figure 1 GIS1 is shown in the image.

[0074] like Figure 2 As can be seen, the grounding conduit 6 is arranged to be rotationally symmetrical about the longitudinal central axis A. The grounding conduit 18 is configured to be electrically connected to a reference potential source, such as ground. The grounding conduit 18 is also configured to allow the flow of reverse current in the direction opposite to the current flowing in conductor 16.

[0075] Conductor 16 is made of conductive material and extends along the same longitudinal central axis A as grounding pipe 18. Conductor 16 and grounding pipe 18 are spaced apart in the radial direction.

[0076] The sensing device 17 is designed as a so-called low-power instrument transformer (LPIT), comprising a voltage sensor 21 based on a capacitive effect voltage transformer (CEVT) configured to measure the value of a conductor-to-tube voltage equal to the potential difference between the grounding tube 18 and the conductor 16; and a current sensor 22 based on a Rogowski effect current transformer (RECT) configured to measure the value of the current flowing through the conductor 16. According to the invention, the voltage sensor 21 and the current sensor are located in the same location and assembled together to form an integral, single-unit construction.

[0077] exist Figure 2In the specific embodiment shown, the grounding conduit 18 is designed in multiple parts to facilitate the assembly of the transmission line 6 with instruments, and includes a first grounding conduit portion 18a and a second grounding conduit portion 18b, which are formed as hollow cylinders extending adjacent to each other along a central axis A. Each grounding conduit portion 18a, 18b includes radially extending flanges 23a, 23b for fastening purposes. An annular tube connector 24 is inserted into the axial space between the flanges 23a, 23b of the grounding conduit portions 18a, 18b and has a substantially U-shaped cross-section with two radial legs 26 and an axial portion 27 connecting the radial legs 26 to each other. The radial legs 26 are fastened to the flanges 23a, 23b of the grounding conduit portions 18a, 18b using fasteners 28 (e.g., bolts that pass through openings in the flanges 23a, 23b and are screwed into threaded holes formed in the radial legs 26 of the tube connector 24).

[0078] exist Figure 2 In the configuration of the pipe connector 24 shown, the axial portion 27 of the pipe connector 24 is positioned to project radially outward beyond the flanges 23a, 23b, and the radial leg 26 together with the axial portion 27 defines a groove 29 therebetween on its inward surface side, such that the groove 29 opens toward the internal cavity 19 of the transmission line 6.

[0079] The groove 29 is annular in shape, defined in a plane orthogonal to the central axis A, and generally positioned radially horizontally at the flanges 23a, 23b. The groove 29 may include at least one through-hole 31 formed through the axial portion 27 of the pipe connector 24 to connect the inner cavity 19 to the outside of the grounding pipe 18. A compression sealing gasket 32 ​​is disposed in the through-hole 31 to prevent insulating gas filling the inner cavity 19 from escaping to the outside via the through-hole 31.

[0080] The recess 29 is arranged to receive part of the sensing device 17 therein, in particular the current sensor 22.

[0081] Figure 3 The image also shows a sensing device 17 including a voltage sensor 21 and a current sensor 22. Figure 3 It shows Figure 2 A magnified detailed view of section I. The capacitive voltage sensor 21 includes a substrate 33, a reference plate 34, and a sensing plate 36. The substrate 33, reference plate 34, and sensing plate 36 are each cylindrical and coaxial with respect to the main axis. In the mounted state of the sensing device 17, as shown... Figure 2 and Figure 3 As shown, the main axis coincides with the longitudinal center axis A of the transmission line 6. For convenience, the center axis A of the transmission line 6 is also referred to as the main axis A of the sensing device 17.

[0082] As from Figure 2 and Figure 3 As can be seen, the reference plate 34 is arranged on the radially outer side 35a of the substrate 33, and the sensing plate 36 is concentrically arranged on the radially inner side 35b of the substrate 33, thus spaced apart from the reference plate 34 by the thickness of the substrate 33. The reference plate 34 and the sensing plate 36 are each made of a conductive material, particularly a metallic material such as copper or aluminum, and the substrate is made of an electrically insulating material, thereby insulating the reference plate 34 from the sensing plate 36. The arrangement of the reference plate 34 and the sensing plate 36, insulated by the substrate 33, thus forms a cylindrical capacitor.

[0083] In a preferred embodiment, the substrate 33 of the voltage sensor 21 is a flexible circuit board, and the reference plate 34 and the sensing plate 36 are metal strips or metal planes located on opposite sides 35a, 36b of the flexible circuit board. They can be printed on the flexible circuit board in a conventional manner.

[0084] As from Figure 2 and Figure 3 As can be seen, in use, the sensing device 17 is arranged in the axial section of the grounding tube 18, which is occupied by the tube connector 24, such that the current sensor 22 is received between the flanges 23a, 23b of the grounding tube portions 18a, 18b. The tube connector 24 may include retaining arms 37 formed on the two axial ends of the tube connector 34 and projecting radially inward. The retaining arms 37 are formed to reach below and support the axial edge 38 of the substrate 33. If desired, the axial edge 38 of the substrate 33 may also be fixed to the retaining arms 37 by gluing, screwing, or other attachment methods.

[0085] For the intended application, particularly in GIS, the flexible circuit board of substrate 33 is preferably made of a flame-retardant epoxy material, preferably a glass-reinforced epoxy laminate (such as FR-4). FR-4 is a composite material made of woven glass fiber cloth and epoxy resin adhesive, which is flame-retardant and self-extinguishing when exposed to heat or open flame. These properties, combined with its high mechanical strength and good electrical insulation properties under both dry and wet conditions, make FR-4 suitable for printed circuit boards, and particularly for the intended application in GIS.

[0086] Reference plate 34 is electrically connected to grounding tube 18 such that the potential of reference plate 34 is equal to the potential of grounding tube 18. As will be explained in more detail below, reference plate 34 is grounded to grounding tube 18 via a portion (metallic protective shield) of current sensor 22. Therefore, in the example shown, reference plate 34 is formed on the outer side of substrate 33 such that its axial end does not contact the retaining arm 37 of tube connector 24. Alternatively, reference plate 34 may be formed to cover the entire outer surface of substrate 33 and directly connected to the retaining arm 37 of tube connector 24, such that reference plate 34 can be connected to grounding tube 18 via tube connector 24.

[0087] The sensing plate 36 is located on the inner side of the substrate 33, such that its axial end is located at a certain distance from the retaining arm 37 of the pipe connector 24 and does not contact the retaining arm 37 of the pipe connector 24.

[0088] The voltage sensor thus formed and arranged is suitable for outputting a measured voltage signal representing the voltage value between the reference plate 34 and the sensing plate 36.

[0089] The Rogowski coil current sensor 22 includes a toroidal main board 39 centered on a main axis A and made of an electrically insulating material, and a toroidal Rogowski coil 41 carried by the main board 39. The Rogowski coil 41 includes a winding 42 made of a conductive material. As is generally known, the winding 42 of the Rogowski coil 41 generally forms two concentric turns formed by a single conductor.

[0090] As from Figures 2 to 4 As can be seen, the current sensor 22 has an annular shape around the main axis A and is arranged concentrically around the voltage sensor 21. The current sensor 22 is located inside the grounding tube 18 and around the conductor 16. In the example shown, the current sensor 22 is received in the groove 29 of the tube connector 24 and is concentric with the reference plate 34 and sensing plate 36 of the voltage sensor 21.

[0091] To make the sensing device 17 more compact, lighter, cheaper, easier to manufacture, and easier to assemble than known sensing devices, the voltage sensor 21 and the current sensor 22 are located in the same position and combined together, such that the current sensor 22 is placed directly around the voltage sensor 21 (i.e., the reference plate 34), wherein the inner diameter of the current sensor 22 substantially corresponds to the outer diameter of the voltage sensor 21. The current sensor 22 is fixedly attached (particularly soldered) to the reference plate 34 of the voltage sensor 21, thereby forming an integral structure of the sensing device 17 including the current sensor 22 directly supported on the voltage sensor 21.

[0092] This results in a cost-effective, less complicated and less expensive construction that requires fewer parts for assembly and installation and is easy to manufacture and assemble.

[0093] See also Figure 4 and Figure 5 The main board 39 of the current sensor 22 is in an annular shape centered on the main axis A of the sensing device 17. The main board 39 is substantially flat and extends in a radial plane substantially orthogonal to the main axis A.

[0094] A motherboard 39, made of an electrically insulating material, carries a Rogowski coil 41, which includes a winding 42 made of a conductive material. In the illustrated embodiment, the winding 42 includes a plurality of winding arms 43 attached to the motherboard 39. The winding arms 43 are arranged on and cover two radially extending end faces 44a, 44b of the motherboard 39. The winding arms 43 extend radially relative to a main axis A and are spaced apart from each other circumferentially around the main axis A. The winding 42 further includes a metallized hole 46 that passes through the motherboard 39 at the level of the ends of the winding arms 43 and electrically connects the winding arm 43 located on one end face 44a of the motherboard 39 to the winding arm 43 located on the other end face 44b of the motherboard 39. The resulting current sensor 22 is adapted to output a signal representing the current flowing through the conductor 16 surrounded by the Rogowski coil 41.

[0095] The winding arms 43 are located on the end faces 44a and 44b of the main board 39, such that the radial ends of the winding arms 43 are recessed relative to the circular edges of the main board 39. In other words, the radial dimension of the inner radial end of each winding arm 43 is greater than the radial dimension of the inner edge of the main board 39, and the radial dimension of the outer radial end of each winding arm 43 is smaller than the radial dimension of the outer edge of the main board 39.

[0096] In a preferred embodiment, the main board 39 of the current sensor 22 may be a flexible circuit board, and the winding arm 43 of the Rogowski coil 41 may be conductive traces printed on the end faces 44a, 44b of the flexible circuit board. The flexible circuit board is preferably made of a flame-retardant epoxy material, particularly a glass-reinforced epoxy laminate, such as FR-4. As mentioned above, this material is particularly suitable for the currently intended application. Printing may include any techniques known in the art, such as directly printing or depositing a uniform layer of conductive material onto the end faces 44a, 44b of the main board 39, and then using a mask and acid to remove portions of the conductive material, leaving only the portion forming the winding arm 43. The Rogowski coil 41 may be designed as an unsaturated Rogowski coil, providing the desired distortion-free and hysteresis-free output signal representing a voltage proportional to the first derivative of the main current flowing through conductor 16 (which passes through sensing device 17).

[0097] The Rogowski coil 41, including the winding arm 43 and the metallized hole 46, may be made of copper or aluminum or other suitable conductive material.

[0098] In a particularly preferred embodiment of the sensing device 17, the substrate 33 of the voltage sensor 21 and the main board 39 of the current sensor 22 are made of the same flexible circuit board material, particularly FR-4 or an equivalent flame-retardant epoxy material. The reference board 34, sensing board 36, and Rogowski coil 41 are preferably all made of the same metallic material, particularly copper. Both sensors 21 and 22 are thus based on the same material and can be easily and cost-effectively manufactured and assembled together as a single unit, reducing the number of components and materials, and using the same technology to produce both printed circuit boards. The resulting sensing device 17 can be very compact, lightweight, and relatively inexpensive, and allows for easy integral integration within devices with a short axial and small radial diameter, particularly within a GIS enclosure. Furthermore, the use of the same material results in the voltage sensor 21 and the current sensor 22 having similar thermal expansion and contraction characteristics under different environmental and operating conditions.

[0099] To protect the mainboard 39, particularly the printed circuit board including the winding arm 43, from damage caused by impacts and external hazards, and also to protect the Rogowski coil 41 from electromagnetic interference that could impair accurate current measurements, a protective shield 47 is provided. The protective shield 47 is made of a metallic material. The protective shield 47 can be configured to substantially surround the mainboard 39 including the Rogowski coil 41.

[0100] The protective shield 47 includes at least protective plates 48a and 48b, which are axially arranged on both sides of the main board 39 such that they are parallel to the main board 39 and extend coaxially with the main axis A of the sensing device 17. The protective plates 48a and 48b are made of metal.

[0101] In addition to the protective plates 48a, 48b covering the annular end faces 44a, 44b of the motherboard 39, the protective shield 47 may further include a cylindrical plate 49 covering the radially outer surface 51 of the motherboard 39. The cylindrical plate 49 is also made of metal and may be a metal layer printed on the radially outer surface 51 of the metal plate 39. The cylindrical plate 49 may preferably be formed continuously and integrally with the protective plates 48a, 48b, or may be electrically connected to them in some other manner. In some embodiments, the cylindrical plate 49 may be omitted.

[0102] Protective plates 48a and 48b are positioned axially at a distance from the main plate 39, such that the metal layer provided by the protective plates 48a and 48b is axially spaced from the winding arm 43 and metallized hole 46 of the Rogowski coil 41, which are located on the end faces 44a and 44b of the main plate 39. Each protective plate 48a and 48b is separated from the main plate 39 by means of an insulating material layer 52 directly disposed on the end faces 44a and 44b. Optionally, the radial outer surface 51 of the main plate may also include the insulating material layer 52, but this is not mandatory. The insulating material layer 52 also serves to secure the protective plates 48a and 48b and the cylindrical plate 49 (if any) to the main plate 39 by adhesive bonding. Alternatively, mechanical attachment may be used.

[0103] exist Figures 2 to 5 In the preferred embodiment shown, a portion 53 of the reference plate 34, positioned directly adjacent to the radially inner surface 54 of the motherboard 39, forms the radially inner portion 56 of the metal protective shield 47 and is arranged to shield the Rogowski coil 41 from the influence of the electric field. Specifically, since the reference plate 34 of the voltage sensor 21 is located between the sensing plate 36 of the voltage sensor 21 and the current sensor 22 and is grounded, the reference plate 34 can block electric field lines from or reaching the sensing plate 36. Therefore, no additional shielding is required for the Rogowski coil located radially inner to the current sensor 22.

[0104] The protective shield 47, comprising the protective plates 48a and 48b, the cylindrical plate 49, and the portion 53 of the reference plate 34, together forms a grounded metal cage that substantially surrounds the entire winding 42 of the Rogowski coil 41, thereby protecting it from external electric fields and interference. The protective shield 47 also increases the stability and rigidity of the entire multilayer structure of the current sensor 22. Together with the insulating material layer 52, the protective shield 47 further prevents the deposition of foreign particles between the winding arms 43 of the winding 42, thus avoiding the risk of short circuits in the winding 42.

[0105] To secure the current sensor 22 to the voltage sensor 21 and form a protective shield 47 substantially around the entire circumference of the main board 39, protective plates 48a and 48b are soft soldered to the reference plate 34 at the interface between the radially inner portion 57 of the protective plates 48a and 48b and the portion 53 of the reference plate 34 using conductive solder. A weld 58 is formed on both axial sides of the current sensor 22, around the entire circumference of the reference plate 34 at the interface to the protective plates 48a and 48b. The weld 58 provides a stable mechanical connection between the current sensor 22 and the voltage sensor 21 and complements the protective metal cage formed by the protective shield 47 surrounding the winding 42 of the Rogowski coil 41. Since the protective shield 47 is grounded, the reference plate 34 is also grounded via the weld 58.

[0106] In a preferred embodiment, the protective plates 48a, 48b are adapted to facilitate soldering to the reference plate 34 while avoiding partial overheating and potential damage. To this end, during the production of the protective plates 48a, 48b, or at least before performing soldering, a portion of the metallic material of the protective plates 48a, 48b may be omitted or removed from the radially inner portion 57. Doing so reduces the conductivity at the interface between the protective plates 48a, 48b and the reference plate 34, which facilitates minimizing or at least reducing heat input during the soldering process, thereby avoiding or at least reducing the risk of thermal damage to the Rogowski coil 41 during the soldering process.

[0107] The sensing device 17 according to the invention is produced by first printing or depositing winding arms 43 on the axial end faces 44a, 44b of the flexible circuit board of the main board 39. Then, holes are drilled through the main board 39 at the ends of the winding arms 43, and metallized by depositing metal material on the walls of each hole, thus forming metallized holes 46. The metallized holes 46 are then filled with a conductive material to electrically connect the winding arms 43 disposed on opposite end faces 44a, 44b to each other. Subsequently, protective plates 48a, 48b and cylindrical plates 49 (if present) are placed or formed on the end faces 44a, 44b and radial outer surface 51 of the main board 39, and assembled thereon via an insulating material layer 52. The voltage sensor 21 is formed by printing or depositing metal layers on opposite radial inner surfaces 35a and radial outer surfaces 35b of the flexible circuit board of the cylindrical substrate 33 to form a reference plate 34 and a sensing plate 36 on the cylindrical substrate 33. The voltage sensor 21 is designed such that its external dimensions match the internal dimensions of the current sensor 22. The current sensor 22 is then placed around the voltage sensor 21 and secured to the voltage sensor 21 by soldering protective plates 48a, 48b to the reference plate 34 to form a weld 58.

[0108] The resulting sensing device 17 is designed and assembled into a single unit, having a voltage sensor 21 and a current sensor 22 located in the same position and mechanically connected to each other, such that the current sensor 22 is directly carried by the voltage sensor 21. This results in a compact, cost-effective construction that requires fewer parts for assembly and installation, and is easy to manufacture and assemble. The sensing device is arranged to provide reliable and accurate voltage and current measurements and is suitable for a variety of applications, including GIS in HV or MV substations.

[0109] For example, the sensing device 17 can be positioned inside the transmission line 6 of the GIS1 and attached to the transmission line 6 using the radial leg 26 of the pipe connector 24. Advantageously, both the voltage sensor 21 and the current sensor 22 can be located directly in the insulating gas filling the internal cavity 19 of the transmission line 6.

[0110] As from Figure 2 and Figure 3 As can be seen, the current sensor 22 can be positioned on the voltage sensor 21 such that when the sensing device 17 is finally assembled within the transmission line 6, one of the protection plates 48a and 48b (protection plate 48a in this example) contacts the inward radial surface 59 of the pipe connector 24, which forms one of the sides of the groove 29. Through this contact, the protective shield 47 and the reference plate 34 can be electrically connected to the grounding pipe 18 via the pipe connector 24, so that the potential of the protective shield 47 and the reference plate 34 is equal to the potential of the grounding pipe 18, i.e., the ground potential.

[0111] In other embodiments, instead of a direct planar connection between the protective plate 48a and the radial surface 59 of the pipe connector 24, or in addition to such a direct planar connection, a grounding connection can be established via a wired connection or using resilient contact pieces 60. Figure 2 In some embodiments, such a contact piece 60 is shown as being positioned between the cylindrical plate 49 of the protective shield 47 and the inward surface of the pipe connector 24. The contact piece 60 can be positioned at any suitable location to allow the protective shield 47 or reference plate 34 to contact the pipe connector 24 or grounding pipe 18. The contact piece 60 is made of a conductive material (such as copper) and provides suitable mechanical properties and conductivity to ensure stable mechanical and electrical contact for grounding purposes.

[0112] As from Figure 3 and Figure 4 As can be seen, the sensing device 17 may further include at least one temperature sensor 61. The temperature sensor 61 may be attached to the current sensor 22 at a predetermined location and configured to measure the temperature in corresponding predetermined volumes relative to the current sensor 22 and the voltage sensor 21. In the present case, the temperature sensor 61 is attached to the radially outer side of the main board 39 or the cylindrical plate 49. The temperature sensor 61 may also be positioned at the end faces 44a, 44b of the main board 39 or at the protective plates 48a, 48b, or may be positioned at and attached to the voltage sensor 21, particularly its substrate 33. If desired, two or more temperature sensors 61 may be provided at circumferentially spaced locations.

[0113] like Figure 3The instructions further indicate that each of the voltage sensor 21, current sensor 22, and temperature sensor 61 includes a line 62 that connects sensors 21, 22, and 61 to a computer device 63, which may be located outside the transmission line 6. For example, the computer device 63 may be arranged in… Figure 1 The control box 12 of the GIS1 shown is equipped with line 62, which allows measurement signals provided by sensors 21, 22, and 61 to be transmitted to computer device 63.

[0114] The computer device 63 is configured to calculate the conductor-to-conductor voltage between the grounding pipe 18 and the conductor 16 based on the voltage signal output by the voltage sensor 21, and to calculate the current flowing through the conductor 16 based on the output signal provided by the current sensor 22. It should be noted that the current sensor 22 provides a voltage signal proportional to the first derivative of the main current flowing through the conductor 16. The computer device 63 can then obtain the corresponding current measurement value by integrating the output signal provided by the current sensor 22.

[0115] The computer device 63 may be further configured to use the sensed temperature signals provided by the temperature sensors(s) ...

[0116] Line 62 can transmit through one or more holes (such as through-hole 31) passing through conduit connector 24 and / or grounding conduit 18. Alternatively, measurement signals output by sensors 21, 22 and 61 can be wirelessly transmitted to a computer device 63 located outside transmission line 6.

[0117] Figure 6 An alternative embodiment is shown, comprising two RECT-based current sensors 22 attached to a single voltage sensor 21, thereby forming a sensing device 17 positioned around a single inductor 16. The two current sensors 17 are stacked axially and supported against each other, while being substantially insulated from each other. Each individual current sensor 22 is substantially aligned with... Figure 2-5 The embodiment of the current sensor 22 shown is configured as described above. In this example, two current sensors 22 are arranged back-to-back, with their mainboards 39 positioned close to each other in the axial direction and separated from each other only by a single insulating material layer 52. The protective plates 48a and 48b between the two mainboards 39 can be omitted.

[0118] Figure 6The two current sensors can be electrically connected to each other in series or parallel. In a series connection, the two current sensors 22 provide a larger cross-sectional area for the main board 39 and the Rogowski coil 41, which increases the sensitivity of the resulting combined current sensor 22 and reduces its radial dimension. Such embodiments, which increase the axial dimension of the current sensor 22 while reducing its radial dimension, have proven advantageous given space constraints in GIS.

[0119] As an alternative, the two current sensors 22 can be connected in parallel. The parallel connection of the current sensors 22 provides redundancy to enhance the reliability of current measurement and to enhance operational safety in the event of a failure of one of the current sensors 22.

[0120] If two current sensors 22 are provided, a temperature sensor 61 can be assigned to each current sensor 22, and the temperature sensors 61 can be positioned offset from each other in the circumferential direction for ease of processing, including wiring and connecting the temperature sensors 61 to the computer device 63.

[0121] Now see Figure 7 A schematic cross-sectional view of the transmission line 6 according to another embodiment of the invention is shown in a plane orthogonal to the longitudinal axis or main axis A of the transmission line 6. In this embodiment, the transmission line 6 is arranged for a three-phase system, wherein three main conductors 16 are disposed within a grounding conduit 18. The conductors 16 extend along the longitudinal axis or main axis A and are spaced apart from each other in the circumferential direction. Each conductor 16 corresponds to a corresponding electrical phase and transmits the phase current from one side of the transmission line 6 to the other.

[0122] like Figure 7 As shown, the sensing device 17 according to any of the above embodiments is associated with each main body 16. Each sensing device 17 consists of a voltage sensor 21 and a current sensor 22. The voltage sensor 21 includes a substrate 3 with a reference plate 34 and a sensing plate 36, and the current sensor 22 includes a main body 39 and a Rogowski coil 41. Each sensing device 17 is arranged only around the corresponding conductor 16 between the grounding tube 18 and the corresponding conductor 16.

[0123] For clarity, in the illustration Figure 7 Details regarding the installation of the sensing device 17 and conductor 16 in transmission line 6 are omitted. Generally, the sensing device 17 can be assembled as described above. Figure 2 and Figure 3 The conductor 16 is attached to the transmission line 6 in the manner shown and described. The conductor 16 may be supported in the transmission line 6 by a corresponding flange (not shown). There are several different ways to support the conductor 16 and the corresponding sensing device 17 in the internal cavity 19 of the three-phase transmission line 6.

[0124] A sensing device 17 is provided, comprising: a capacitive voltage sensor 21 including a substrate 33, a reference plate 34, and a sensing plate 36, each being cylindrical and coaxial with respect to the main axis A of the sensing device 17; the reference plate 34 being arranged radially outward on the substrate 33, and the sensing plate 36 being concentrically arranged radially inward on the substrate 33; the reference plate 34 and the sensing plate 36 being each made of a conductive material; the substrate 33 being made of an electrically insulating material; the voltage sensor 21 being adapted to output a voltage signal representing the voltage value between the reference plate 34 and the sensing plate 36; and a Rogowski coil current sensor 22, the current sensor 22 including a toroidal main plate 39 centered on the main axis A and made of an electrically insulating material, and a ring-shaped Rogowski coil 41 carried by the main plate 39; the current sensor 22 being adapted to output a signal representing the current flowing through a conductor 16 surrounded by the Rogowski coil 41. The current sensor 22 is arranged concentrically around the voltage sensor 21 and fixedly attached to the reference plate 34 of the voltage sensor 21, thereby forming an integral structure of the sensing device 17 including the current sensor 22 directly supported on the voltage sensor 21.

Claims

1. A sensing device (17), comprising: A capacitive voltage sensor (21) includes a substrate (33), a reference plate (34), and a sensing plate (36). The substrate (33), the reference plate (34), and the sensing plate (36) are each cylindrical and coaxial with respect to the main axis (A) of the sensing device (17). The reference plate (34) is arranged on the radially outer side (35a) of the substrate (33), and the sensing plate (36) is arranged concentrically on the radially inner side (35b) of the substrate (33) with respect to the reference plate (34). The reference plate (34) and the sensing plate (36) are each made of a conductive material, and the substrate (33) is made of an electrically insulating material. The voltage sensor (21) is adapted to output a voltage signal representing the voltage value between the reference plate (34) and the sensing plate (36). as well as A Rogowski coil current sensor (22) includes a toroidal main plate (39) centered on the main axis (A) and made of electrically insulating material, and a ring-shaped Rogowski coil (41) carried by the main plate (39). The Rogowski coil (41) includes a winding (42) made of conductive material and comprising a plurality of winding arms (43) arranged on radially extending end faces (44a, 44b) of the main plate (39) and extending along... The circumferential directions are spaced apart from each other and extend radially relative to the main axis (A); and the metallized hole (46) passes through the main board (39) and electrically connects the winding arm (43) located on one end face (44a) of the main board (39) to the winding arm (43) located on the other end face (44b) of the main board (39), the current sensor (22) being adapted to output a signal representing the current flowing through the conductor (16) surrounded by the Rogowski coil (41); The current sensor (22) is arranged concentrically around the voltage sensor (21) and fixedly attached to the reference plate (34) of the voltage sensor (21), thereby forming an integral structure of the sensing device (17) including the current sensor (22) directly supported on the voltage sensor (21).

2. The sensing device (17) according to claim 1, characterized in that, The substrate (33) of the voltage sensor (21) is a flexible circuit board, and the reference plate (34) and the sensing plate (36) are metal strips printed on the flexible circuit board.

3. The sensing device (17) according to claim 2, characterized in that, The flexible circuit board is made of flame-retardant epoxy material, preferably glass-reinforced epoxy laminate, especially FR-4.

4. The sensing device (17) according to any one of the preceding claims, characterized in that, The main board (39) of the current sensor (22) is a flexible circuit board, and the winding arm (43) of the Rogowski coil (41) is a conductive trace printed on the end face (44a, 44b) of the flexible circuit board.

5. The sensing device (17) according to claim 4, characterized in that, The flexible circuit board is made of flame-retardant epoxy material, preferably glass-reinforced epoxy laminate, especially FR-4.

6. The sensing device (17) according to any one of the preceding claims, characterized in that, The reference plate (34) and the sensing plate (36) are made of copper or aluminum, and the winding arm (43) and the metallized hole (46) are made of copper or aluminum.

7. The sensing device (17) according to any one of the preceding claims, characterized in that, The substrate (33) of the voltage sensor (21) and the main board (39) of the current sensor (22) are made of the same flexible circuit board material, and the reference board (34), the sensing board (36) and the winding (42) of the Rogowski coil (41) are made of the same metal material.

8. The sensing device (17) according to any one of the preceding claims, characterized in that, The current sensor (21) is soldered to the reference plate (34) of the voltage sensor (21).

9. The sensing device (17) according to any one of the preceding claims, characterized in that, The current sensor (21) further includes a metal protective shield (47) arranged to protect the main board (39) and the winding (42) of the Rogowski coil (41) from possible damage, and to shield the Rogowski coil (41) from the influence of an external electric field. The protective shield (47) includes protective plates (48a, 48b) arranged axially on both sides of the main board (39) to be parallel to the main board (39) and coaxial with the main axis (A) of the sensing device (17).

10. The sensing device (17) according to claim 9, characterized in that, The metal protective shield (47) is arranged substantially around the winding (42) of the main board (39) and the Rogowski coil (41), wherein a portion (53) of the reference plate (34) forms a radially inner portion (56) of the metal protective shield (47) and is arranged to shield the Rogowski coil (41) from the sensing plate (36).

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