Rfid detection system for power cable accessories and power cable accessory comprising such rfid detection system

Abstract

RFID detection system for power cable accessories and power cable accessory comprising such RFID detection system. RFID detection system for power cable accessories (100) comprising: - a housing (110) having an outer surface (111) configured to be attached to an inner surface of a tubular casing (220, 320) of a power cable accessory (200, 300), the housing (110) being made of resin; - an electronic processing and control unit (120) encapsulated in the housing (110), the electronic processing and control unit (120) being configured to implement a passive RFID tag; - one or more sensors (130) connected to the electronic processing and control unit (120) and not covered by the housing (110), thus being at least partially exposed to the environment outside the housing (110).

Description

Technical Field

[0001] This disclosure relates to an RFID detection system for power cable accessories, and to power cable accessories, such as cable terminals or connectors, that include such an RFID detection system. Background Technology

[0002] For the purposes of this specification, a power cable includes at least one cable core, which is typically formed of a conductive metal conductor covered by an insulation system, which is typically covered by an outer protective sheath, the outermost layer of the cable. The insulation system may be formed sequentially of an inner semiconductor layer, an intermediate insulation layer, and an outer semiconductor layer. The cable may also include a metal shield between the outer protective sheath and the insulation system, the metal shield being configured to ground the cable.

[0003] For the purposes of this disclosure, in relation to a termination for power cables, it means a device suitable for connecting a power cable conductor to a bare conductor, i.e., an electrical conductor that is different from the power cable and has no solid insulation system applied thereto. The termination includes an electrical connection mechanism between the power cable conductor and the bare conductor, and an electrical separation mechanism between the outer surface of the cable and the components connected thereto (typically at ground potential) and elements under tension (such as the bare conductor).

[0004] Terminals typically include:

[0005] - Electric field control elements, often called "stress members" or "stress cones," are designed to be fitted onto power cables;

[0006] - An insulator designed to surround the terminal portion of an electrical cable and to be connected to an electric field control element so as to also at least partially surround it; and

[0007] - A tubular housing that surrounds the aforementioned components and the terminal portion of the power cables.

[0008] The insulator can be the space between cables fitted with stress cones, optionally filled with an insulating fluid such as silicone oil, SF6 or synthetic air, or filled with an insulating solid such as silicon.

[0009] Insulators and stress cones are also collectively referred to as "insulating components".

[0010] For the purposes of this disclosure, in relation to a connector, it means a device adapted to electrically connect two power cables to each other and restore insulation and electric field control, such as one or more semiconductor layers, at the exposed joint between the conductors of the joined cables.

[0011] For example, a connector may include one or more insulators and electric field control elements (also collectively referred to as "insulating components") extending along the longitudinal direction X between two opposite end portions of the two cables to be joined, so as to be fitted onto the conductor connection in an assembly configuration. Furthermore, a tubular housing may be provided around one or more insulators and electric field control elements to prevent possible crushing.

[0012] In any situation, it is necessary to monitor cable accessories in order to ensure the safety and proper operation of the system.

[0013] For the purposes of this disclosure, in relation to a power cable accessory system, it means an assembly consisting of an accessory and a power cable (in the case of a terminal) or two joined power cables (in the case of a connector on which the accessory is mounted).

[0014] Therefore, sensors are needed to detect voltage, current, humidity, strain, temperature, pressure, partial discharge, etc.

[0015] US11022498B2 describes an apparatus for measuring variables associated with power cable accessories, the apparatus comprising: an RFID tag including: a sensor configured to generate a signal indicating variables in its environment; an antenna; and an RFID IC (RFID integrated circuit) electrically connected to the sensor and configured to process and modulate the signal generated by the sensor and transmit the modulated signal to an RFID reader via the antenna. The RFID tag may be passive.

[0016] US8733664B2 describes a device for supplying energy to an RFID component, comprising an antenna and an energy storage device. The energy storage device stores energy induced in the antenna by an alternating electromagnetic field during a first time interval. Furthermore, if the energy induced by the alternating electromagnetic field during a subsequent second time interval is insufficient to supply the RFID component, the energy storage device supplies the stored energy to the RFID component to maintain its function during the subsequent second time interval.

[0017] WO2020 / 052983A1 describes a cable conduit comprising: at least one cable, which may be a power line, a data transmission line, and / or an optical fiber; a tube housing the cable within an internal space; and a sensor for sensing environmental conditions within the internal space of the tube, wherein the sensor includes a wireless transmitter for transmitting measurement data to the outside of the tube, and wherein the sensor is positioned in a cavity that fluidly exchanges with the internal space of the tube.

[0018] The cable may include one or more wires, which may be enclosed in a plastic cover. Passive RFID tags with sensing capabilities can be used as sensors.

[0019] The paper “A Review of RFID Sensors: A New Frontier for the Internet of Things” by Costa et al., Sensors 2021, 21(9), 3138, describes a review of technical solutions for RFID sensing and its current or envisioned applications. Summary of the Invention

[0020] The applicant faces a technical challenge: how to monitor the operating conditions of a power cable accessory system over time. Therefore, the applicant considers implementing this monitoring by installing sensors within the power cable accessory system. In this regard, the applicant believes in using sensors capable of wireless communication with external terminals to avoid the use of signal cables running from the inside to the outside of the power cable accessory system. This maintains the system's waterproofness and eliminates the need to modify the installation procedure to accommodate signal cables traversing the power cable accessory system. Furthermore, the applicant considers sensors that do not require continuous power supply but only power when activated. This avoids the use of batteries with limited lifespans and the need for frequent maintenance.

[0021] The applicant then proposes using a passive RFID detection system; in this way, the sensors and all systems are only powered and operate normally when a user queries the RFID detection system via an RFID reader. This RFID detection system needs to be easily installed inside a power cable accessory system, where extreme environmental conditions may occur in terms of temperature and pressure of the fluid that may fill the tubular housing of the accessory system. Therefore, it is necessary to house the RFID system within a housing that ensures wireless exchange of energy and signals, as well as protection against water, high temperatures, and more generally, protection from external reagents.

[0022] The applicant then proposes encapsulating the RFID detection system, at least partially, in a housing made of resin. Because resin adheres completely to the electronic components, the resin housing ensures protection against external agents (such as insulating fluids), which in turn protect against potential contamination due to electronic component malfunction. Furthermore, the resin housing can be easily attached to the inner surface of the tubular housing of the power cable accessory system. The applicant then considers fabricating the housing by injecting resin into a mold containing the RFID detection system components to be encapsulated.

[0023] Finally, the applicant argues that one or more sealing holes were implemented in the resin housing to allow the sensor to communicate with the outside of the housing and detect environmental conditions in such a space.

[0024] Therefore, according to the first aspect, this disclosure relates to an RFID detection system for power cable accessories, comprising:

[0025] - A housing having an outer surface configured to form the inner surface of a tubular housing attached to a power cable accessory, the housing being made of resin;

[0026] - An electronic processing and control unit, encapsulated in the housing, the electronic processing and control unit being configured to implement a passive RFID system;

[0027] - One or more sensors connected to the electronic processing and control unit and not covered by the housing, thus being at least partially exposed to the environment outside the housing.

[0028] The outer surface of the casing can be convex.

[0029] In one embodiment, the resin is an epoxy resin, a silicone resin, or a polyurethane resin.

[0030] In one embodiment, the RFID detection system includes at least one board. Each board may be divided into two or more board sections, which are connected to each other, for example, by bolts, screws, or glue. At least one board is a printed circuit board on which electronic components of the electronic processing and control unit are mounted. At least one sensor may be mounted on the same printed circuit board on which the electronic processing and control unit is mounted, optionally along with other auxiliary components. The same or another board may be provided with at least one of the sensors.

[0031] In one embodiment, at least one sensor is configured to detect environmental parameters outside the housing.

[0032] In one embodiment, at least one of the sensors may be located at least partially outside the housing and connected to the electronic processing and control unit via a signal cable passing through a corresponding hole in the housing.

[0033] According to the second aspect, this disclosure relates to a power cable accessory, comprising:

[0034] - An insulating assembly comprising an insulator and an electric field control element adapted to be fitted to a single power cable or two joined power cables;

[0035] - A tubular housing adapted to accommodate the insulating components;

[0036] - According to the RFID detection system of the above embodiments, the outer shell is connected to the tubular housing.

[0037] In one embodiment, the tubular housing is coupled to the metal portion, and the housing of the RFID detection system is positioned close to and separate from the metal portion.

[0038] In one embodiment, the power cable accessory is a terminal, the tubular housing is made of an insulating material, such as an insulator in the form of an insulating fluid, disposed between the stress cone and the tubular housing, the metal portion is a metal base support element, and the outer shell is positioned between the metal base support element and the stress cone.

[0039] In another embodiment, the power cable accessory is a connector in which a tubular housing is made of insulating material and a metal portion surrounding the power cable is attached at each end.

[0040] For the purposes of this specification and the appended claims, unless otherwise stated, all figures representing quantities, quantities, percentages, etc., shall be understood to be modified by the term "about" in all cases. Furthermore, all ranges include any combination of the maximum and minimum points disclosed, and include any intermediate ranges therein, which may or may not be specifically enumerated herein.

[0041] Furthermore, the terms "a" and "an" are used to describe elements and components of this disclosure. This is done merely for convenience and to give the general meaning of this disclosure. Unless it is obvious otherwise, the description should be understood to include one or at least one, and the singular includes the plural.

[0042] As an "insulating material," it refers to having a strength of less than 10. -12 Materials with an electrical conductivity of S / m.

[0043] As a "semiconductor material," it refers to materials with properties ranging from 10... -2 Materials with electrical conductivity up to 100 S / m. Attached Figure Description

[0044] Other features will be apparent from the detailed description given below with reference to the accompanying drawings, wherein:

[0045] Figures 1A to 1E These are perspective views of the bottom, main lateral, top, and secondary lateral sides of the RFID detection system according to this disclosure;

[0046] Figures 2A to 2C This is a schematic perspective view showing the steps of a process for making an RFID detection system according to the present disclosure;

[0047] Figure 3 This is a schematic perspective view of the printed circuit board and board included in the RFID system according to this disclosure;

[0048] Figure 4 This is a schematic cross-sectional view of the terminal according to this disclosure;

[0049] Figure 5 It is a schematic cross-sectional view of the joint according to this disclosure. Detailed Implementation

[0050] Referring to the accompanying drawings, an RFID detection system 100 for power cable accessories according to the present disclosure is schematically illustrated.

[0051] In particular, power cable accessories 200 and 300 can be terminal 200 or connector 300, such as Figure 4 and Figure 5 As shown.

[0052] According to this disclosure, one or two joined power cables 400 and power cable accessories 200, 300 applied to such one or two joined power cables constitute part of a power cable accessory system.

[0053] Each power cable 400 includes at least one electrical conductor 410 and a cable insulation system 420 surrounding the at least one electrical conductor. The cable insulation system 420 may include an inner semiconductor layer surrounding and contacting the electrical conductor, a cable insulation layer surrounding and contacting the corresponding inner semiconductor layer, and an outer semiconductor layer surrounding and contacting the corresponding insulation layer. An outer protective sheath is provided around the outer semiconductor layer, which is considered the outermost layer of the cable. In many applications, the power cable includes a metal shield (not shown) between the outer protective sheath and the insulation system 420, which is configured to ground the cable.

[0054] According to the power cable accessories 200 and 300 disclosed herein, the following are included:

[0055] - An insulating assembly, comprising insulators 230, 330 and electric field control elements 210, 310 adapted to be fitted to a power cable or two joined power cables 400;

[0056] - Tubular housings 220, 320 suitable for accommodating insulating components;

[0057] - RFID detection system 100 connected to tubular housings 220, 320.

[0058] The tubular housings 220 and 320 may be made of insulating material and are connected to the metal portions 240 and 340 at one / each longitudinal end of the power cable 400.

[0059] Referring to the accompanying drawings, the RFID detection system 100 includes a housing 110 made of resin and having an outer surface 111 that is configured to be the inner surface of a tubular housing 220, 320 attached to a power cable accessory assembly 200, 300.

[0060] The housing 110 may be made of epoxy resin, silicone resin, or polyurethane resin.

[0061] More generally, the housing 110 is made of resin that can be effectively attached to the tubular housing material and is chemically inert relative to the fluid optionally present in the tubular housing.

[0062] In one embodiment, the outer surface 111 has a convex portion. The outer surface 111 of the housing 110 may be convex and may have a radius of curvature that is complementary to the radius of curvature of the inner surface of the tubular housings 220, 320.

[0063] In power cable accessory assemblies 200 and 300, housing 110 is connected to the inner surface of tubular housings 220 and 320.

[0064] The RFID detection system 100 also includes: an electronic processing and control unit 120, which is enclosed in a housing 110 and configured to implement a passive RFID system; and one or more sensors 130, which are connected to the electronic processing and control unit 120 and are not covered by the housing, thus being at least partially exposed to the environment outside the housing.

[0065] In particular, the electronic processing and control unit 120 includes a plurality of electronic components 121 to 126. For example... Figure 3 As shown, the electronic processing and control unit 120 may include one or more capacitors 121, inductors 122, diodes 123, microcontrollers 124, and resistors 125. Furthermore, the electronic processing and control unit 120 includes at least one connector 126a for an antenna cable (i.e., a cable connecting the electronic processing and control unit 120 to, for example, an antenna for harvesting energy, as disclosed below). Additionally, the electronic processing and control unit 120 includes at least one connector 126b for a sensor cable (i.e., a cable connecting the processing and control unit 120 to one of the sensors 130). The number of each component 121 to 126b may vary depending on the specific application and may be designed by those skilled in the art. Other components may be present depending on the specific application and the choice of those skilled in the art. The RFID detection system 100 includes at least one board 132, 133, 134. Each board may be divided into two or more board sections, which are connected to each other, for example, by bolts, screws, or adhesive.

[0066] In the illustrated embodiment, the RFID detection system 100 includes a first board 133, a second board 132, and a third board 134, which are printed circuit boards. An electronic processing and control unit is mounted on the printed circuit board 134.

[0067] A passive RFID system refers to an electronic system that is configured to receive the energy required for operation from the electromagnetic waves of an RFID reader and to transmit information data to the RFID reader in a wireless mode.

[0068] In practice, the passive RFID system 100 includes at least one antenna 127a, 127b. At least one antenna 127a, 127b can be mounted on a board or a printed circuit board.

[0069] like Figure 1C As shown, the first antenna 127a, mounted on the first board 133, is used for energy harvesting and is connected to the cable connector 126a via cable 128 (e.g., in...). Figure 1B (See image). The second antenna 127b (as shown in the image) is mounted on the third board 134 (i.e., the printed circuit board). Figure 1B and Figure 3 (As shown) is used for wireless communication and is connected to a microcontroller 124 and at least one tag chip 124', thereby enabling data logging, device configuration, and upgrades (e.g., Impinj's X-8K tag chip). These electronic components are known in the prior art and will not be described in detail here.

[0070] When the RFID reader interrogates the RFID detection system 100, the electronic processing and control unit 120 receives a power supply through the first antenna 127a. The received energy is used to power all electronic processing and control units 120 and at least one sensor 130.

[0071] The second antenna 127b is alternatively used to wirelessly transmit data detected by at least one sensor 130 to an RFID reader.

[0072] At least one sensor 130 is capable of detecting environmental parameters and / or electrical parameters and / or mechanical parameters.

[0073] For example, a sensor for detecting environmental parameters may include a humidity sensor subunit and / or a pressure sensor subunit; a sensor for detecting electrical parameters may include a voltage sensor subunit and / or a current sensor subunit and / or a partial discharge sensor subunit; and a sensor for detecting mechanical parameters may include a strain sensor subunit.

[0074] In the embodiment shown in the drawings, sensor 130 can be mounted on a second board 132 connected to printed circuit board 134. At least one of the sensors 130, the first sensor 130, can face the outside of housing 110 through a corresponding hole 112 in housing 110.

[0075] In some cases, such as when the RFID detection system 100 is positioned within the cable termination 200, the hole 112 can be sealed, wherein the insulator 230 is an insulating fluid other than air. In this embodiment, at least one first sensor 130 has a surface exposed to the outside of the housing 110, which may be flush with the edge of the sealed hole 112 of the housing 110. In another embodiment, at least one first sensor 130 may protrude beyond the edge of the hole 112 of the housing 110.

[0076] In all these cases, at least one sensor 130 is a sensor for detecting environmental parameters (e.g., temperature and / or pressure and / or humidity of the terminal or connector), having a sensing portion facing outwards from the housing 110 or outside the housing 110.

[0077] In another embodiment, not shown, at least one sensor of the RFID detection system of this disclosure may be located entirely outside the housing and connected to the electronic processing and control unit via a cable passing through a corresponding hole in the housing 110. This at least one external sensor may be a sensor for detecting electrical parameters or a sensor for detecting mechanical parameters.

[0078] Figure 4 The power cable accessory is cable termination 200. In cable termination 200, the insulation components include an insulator 230 in the form of an insulating fluid and a stress cone (electric field control element) 210. Cable termination 200 also includes a tubular housing 220 made of insulating material and a metal portion (or metal base support element) 240.

[0079] exist Figure 4 In the embodiment shown, the RFID detection system 100 is positioned to contact the tubular housing 220, close to the stress cone 210, and separate from the metal portion 240.

[0080] Figure 5 The power cable accessory is a connector 300 that is mounted on two joined power cables 400, each power cable including an electrical conductor 410 surrounded by an insulation system 420. No further description of the cable 400, as is known to those skilled in the art, is provided. The connector 300 includes an insulator 330 and an electric field control element 310, the electric field control element being surrounded by a tubular housing 320 made of insulating material. The tubular housing 320 is coupled to two metal portions 340, each metal portion surrounding the associated cable 400.

[0081] exist Figure 5 In the embodiment shown, the RFID detection system 100 is positioned to contact the tubular housing 320, near one of the electric field control elements 310, and separate from the two metal parts 340.

[0082] RFID detection system 100 can, for example, Figures 2A to 2C The molding technique shown is used to produce it. In the first step, for example, in... Figure 2A In this process, the RFID detection system 100 is placed inside the mold 600, and then the mold 600 is closed with a cover 610 having at least one opening 611 and at least one hollow rod 612 configured to connect to at least one sensor 130. The at least one rod 612 prevents resin from covering the sensor and enables it to communicate with the outside of the housing 110 at the end of the manufacturing process.

[0083] Then, the closed mold 600 is filled with resin through at least one opening 611. The resin is embedded in at least one plate 132, 133, 134, and after the curing step, a housing 110 with an encapsulation that can be pulled out of the mold 600 is formed.

Claims

1. An RFID detection system (100) for power cable accessories, comprising: - A housing (110) having an outer surface (111) configured to be the inner surface of a tubular housing (220, 320) attached to a power cable accessory (200, 300), the housing (110) being made of resin; - An electronic processing and control unit (120), which is encapsulated in the housing (110), the electronic processing and control unit (120) being configured to implement passive RFID tags; - One or more sensors (130) are connected to the electronic processing and control unit (120) and are not covered by the housing (110), thus being at least partially exposed to the environment outside the housing (110).

2. The RFID detection system (100) according to claim 1, wherein the resin is epoxy resin, silicone resin, or polyurethane resin.

3. The RFID detection system (100) according to claim 1, wherein the electronic processing and control unit (120) includes at least one board (132, 133), at least one of the boards (132, 133) is a printed circuit board, the electronic components of the electronic processing and control unit (120) are mounted on the printed circuit board, and at least one of the sensors (130) is mounted on the same printed circuit board on which the electronic processing and control unit is mounted or on another board.

4. The RFID detection system (100) according to claim 3, wherein the at least one sensor (130) is configured to detect environmental parameters outside the housing (110).

5. The RFID detection system (100) according to one or more of the preceding claims, wherein at least one of the sensors (130) is located at least partially outside the housing (110) and is connected to the electronic processing and control unit (120) via a signal cable passing through a corresponding hole (112) in the housing (110).

6. Power cable accessories (200, 300), including: - An insulating assembly comprising an insulator (230, 330) and an electric field control element (210, 310) suitable for assembly into a single power cable (400) or two joined power cables (400). - A tubular housing (220, 320) suitable for accommodating the insulating component; - An RFID detection system (100) according to one or more of the preceding claims, wherein the housing (110) is coupled to the tubular housing (220, 320).

7. The power cable accessory (200, 300) according to claim 6, wherein the tubular housing (220, 320) is coupled to the metal portion (240, 340), and the housing (110) of the RFID detection system (100) is positioned close to and separate from the metal portion (240, 340).

8. The power cable accessory (200, 300) according to claim 6 or 7, wherein the power cable accessory (200) is a terminal, the tubular housing is made of an insulating material, the insulator is disposed between the stress cone and the tubular housing in the form of an insulating fluid, the metal portion is a metal base support element (230), and the housing (110) of the RFID detection system (100) is positioned between the metal base support element (230) and the stress cone (210).

9. The power cable accessory (200, 300) according to claim 6 or 7, wherein the power cable accessory assembly (300) is a connector, the tubular housing being made of insulating material and connecting at each end a metal portion surrounding the power cable (400).

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