Resonator array sensor arrangement

Abstract

The present disclosure relates to a high voltage HV electrical device (50), comprising a sensor arrangement (1), the sensor arrangement comprising: a sensor (2), the sensor being configured to measure a characteristic of the electrical device; a detector (3), the detector being configured to receive a signal (41) from the sensor; an electrical power source (6); and a resonator array (4), the resonator array comprising an array of LC circuits (5), the LC circuits (5) being arranged equidistant from one another along a transmission path between the sensor and the detector, such as an axis between the sensor and the detector, and the resonator array being configured to wirelessly transmit power (42) from the electrical power source (6) to the sensor, and to wirelessly transmit a sensor signal (41) from the sensor to the detector.

Description

Technical Field

[0001] The present disclosure relates to a sensor arrangement for measuring a property of an environment in an electrical device. Background Art

[0002] Power transformers and other high-voltage (HV) equipment typically involve components (core, conductors, paper insulation, structural elements, sensors, etc.) that are exposed to extreme conditions (e.g., in a tank housing filled with insulating oil). This means high electric field strengths due to voltage differences of tens or hundreds of kilovolts, high temperatures exceeding 100 to 130°C due to losses in windings and cores, structural forces and vibrations, support pressures of the order of hundreds of MPa, magnetic fields of the order of 1.5 to 2 T, etc. For the monitoring and control of power transformers, strategically located sensors and their means for their operation (power supply and communication) are essential components. Sensor solutions can be wired (e.g., optical fiber) or wireless (e.g., WiFi or radio frequency, RF and RFID). Conventional conductive line sensor solutions are automatically excluded because they will generally not meet HV insulation requirements. It is possible to transmit power and signals via optical fiber, but the problem is that optical fiber is sensitive to mechanical stress.

[0003] The sensors and means for their operation should not reduce the transformer internal insulation strength or increase the risk of electrical breakdown. They should preferably fit into existing transformer designs, with negligible requirements for design changes or additional space.

[0004] The harsh environments in which sensing systems must operate place high demands on robustness and durability without becoming complex, bulky and / or expensive as many existing wireless (sensing and communication) solutions tend to do.

[0005] Sensor devices require access to an electrical power source throughout their operational life. Conventional long-life batteries are bulky and expensive. However, passive (RF, RFID) wireless technologies do not require batteries. RFID systems can feed power to and signals from the sensing unit, but typically over very short distances (a few dm). The distance required to bridge inside a transformer can be up to several meters, with an associated cumulative potential difference of up to several hundred kilovolts.

[0006] Wireless power transfer from low voltage to high voltage can be achieved through resonator (inductor-capacitor, LC) coils, for example to power sensors in HV environments.

[0007] US 2017 / 167250 relates to the use of resonators to wirelessly transmit power and data down an oil or gas well to a pressure sensor. A first resonator is included in an inner tube coupled to a power source. A second resonator is included in an outer tube that is coupled to a sensor outside the inner tube.

[0008] US 2010 / 177801 relates to a resonant array of temperature sensors for a jet engine or a jet fuel tank.

[0009] US 2017 / 140870 discloses a HV insulator with an embedded resonator coil. The resonator coil forms a series of relay resonators that can be used for wireless power transfer and can provide simultaneous functions of voltage isolation and wireless power transfer in high voltage environments such as those encountered in high voltage power transmission line systems. Summary of the invention

[0010] It is an object of the present invention to provide an improved electrical device comprising means for measuring a property of an environment, in particular an HV environment, in the electrical device.

[0011] According to one aspect of the present invention, a high-voltage (HV) electrical device is provided, which includes a sensor arrangement, the sensor arrangement comprising: a sensor configured to measure a characteristic of the electrical device; a detector configured to receive a signal from the sensor; an electrical power source; and a resonator array, the resonator array comprising an array of LC circuits, the array of LC circuits being arranged equidistant from each other along a transmission path (such as an axis) between the sensor and the detector, and being configured to wirelessly transmit power from the electrical power source to the sensor, and being configured to wirelessly transmit sensor signals from the sensor to the detector.

[0012] According to another aspect of the present invention, a method for detecting a measured characteristic in a high voltage (HV) electrical device is provided, the method comprising: wirelessly transmitting power from an electrical power source to a sensor via a resonator array to power the sensor, wherein the resonator array comprises an array of LC circuits arranged equidistant from one another along a transmission path (such as an axis) between the sensor and the detector; and wirelessly transmitting a signal indicating a measured value of the characteristic from the sensor to the detector via the resonator array.

[0013] According to another aspect of the present invention, there is provided a computer program product comprising computer executable components for causing a controller to perform an embodiment of the method of the present disclosure when the computer executable components are run on a processing circuit included in the controller.

[0014] By arranging the resonator array to wirelessly transmit both power to the sensor and sensor signals to the detector, no separate signal transmission arrangement, such as via a Wireless Local Area Network (WLAN), is required.

[0015] "High voltage" (HV) herein refers to a voltage greater than or equal to 1 KV. A high voltage environment is an environment generated during operation of the high voltage electrical equipment, such that the high voltage electrical equipment includes a high voltage environment when in use.

[0016] It should be noted that any feature of any of the various aspects may be applicable to any of the other aspects, as appropriate. Likewise, any advantage of any of these aspects may be applied to any of the other aspects. Other objects, features and advantages of the attached embodiments will become apparent from the following detailed disclosure, from the attached dependent claims and from the accompanying drawings.

[0017] Generally, all terms used in the claims should be interpreted according to their ordinary meaning in the technical field, unless explicitly defined herein. All references to "one / an / element, device, component, means, step, etc." should be publicly interpreted as referring to at least one instance of the element, device, component, means, step, etc., unless explicitly stated otherwise. Unless explicitly stated, the steps of any method disclosed herein do not have to be performed in the exact order disclosed. The use of "first", "second", etc. for different features / components of the present disclosure is intended only to distinguish the features / components from other similar features / components, rather than to give the features / components any order or hierarchy. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Embodiments will be described by way of example with reference to the accompanying drawings, in which:

[0019] Figure 1 is a schematic diagram of a sensor arrangement according to an embodiment of the present invention, the sensor arrangement comprising a resonator array comprising a one-dimensional (1D) array of coaxial LC circuits.

[0020] Figure 2 is a schematic diagram of a sensor arrangement according to an embodiment of the present invention, the sensor arrangement comprising a resonator array comprising a one-dimensional (1D) array of coplanar LC circuits.

[0021] Figure 3 is a schematic circuit diagram of a planar LC circuit printed on a film according to an embodiment of the present invention.

[0022] Figure 4 is a schematic block diagram of a sensor arrangement according to an embodiment of the present invention.

[0023] Figure 5 is a schematic block diagram of an electrical device including a sensor arrangement according to an embodiment of the present invention.

[0024] Figure 6 is a schematic block diagram of a controller of a sensor arrangement according to an embodiment of the present invention.

[0025] Figure 7 is a schematic flow chart of an embodiment of the method of the present invention. DETAILED DESCRIPTION

[0026] Embodiments will now be described more fully below with reference to the accompanying drawings, in which certain embodiments are shown. However, within the scope of the present disclosure, many other embodiments in different forms are possible. On the contrary, the following embodiments are provided by way of example so that the present disclosure will be thorough and complete, and will fully convey the scope of the present disclosure to those skilled in the art. Throughout the description, the same numbers refer to the same elements.

[0027] Embodiments of the present invention are intended to monitor properties (such as temperature and pressure) in harsh environments of high voltage equipment (such as power transformers) without interfering with insulation property performance. However, embodiments of the present invention may also be used for low voltage (LV) or medium voltage (MV) equipment and their environments. Such monitoring requires the transmission of power and signals over relatively long distances, possibly across potentials of hundreds of kV. The sensor arrangement of the present invention may be viewed as, for example, a wireless monitoring system comprising i) at least one passive sensor unit in the form of an LC resonator having a natural frequency f that is sensitively dependent on the characteristic to be measured, ii) at least one LC resonator array (one-dimensional, two-dimensional or three-dimensional array), the at least one LC resonator array having a fixed natural frequency f0, arranged at limited intervals, and / or iii) a power supply and signal detection unit (which may or may not be integrated with each other) (e.g. an impedance analyzer), which is inductively coupled to the sensor via the resonator array. Embodiments of the present invention may provide robust and low-cost wireless transmission of power and sensor signals over a distance of several meters without the need for embedded energy storage or power harvesting in electrical equipment.

[0028] The sensors and their means for operation preferably do not reduce the internal insulation strength of electrical equipment (e.g. transformers), or increase the risk of electrical breakdown in any way. They should preferably fit into existing equipment designs, with negligible requirements for design changes or additional space.

[0029] Figure 1An embodiment of a sensor arrangement 1 is shown, which comprises an ID resonator array 4 of a plurality of substantially flat (planar) LC circuits 5 (typically simulated LCR circuits having a small resistance R) (here four LC circuits 5a, 5b, 5c and 5d) arranged along axes orthogonal to respective planes of the planar LC circuits 5 (in the plane of the LC circuits 5). Figure 1 The LC circuits 5 are coaxially stacked on top of each other at an axial distance D and equidistant from each other (indicated as dotted lines in FIG. 1 ). Each LC circuit 5 comprises an inductive circuit L and a capacitive circuit C, which comprises at least one capacitor.

[0030] The resonator array 4 is arranged to wirelessly transmit power from an alternating current (AC) electrical power source 6 to at least one sensor 2, thereby powering the sensor, the sensor 2 being configured to measure a characteristic x (e.g., temperature and / or pressure) of an environment in the electrical device (e.g., an HV environment within the electrical device). Additionally, the resonator array 4 is arranged to wirelessly transmit a sensor signal from the sensor 2 to a detector 3, the sensor signal typically comprising information about the measured characteristic x. The detector 3 may, for example, be or include an impedance meter, such as an impedance analyzer.

[0031] The sensor arrangement 1 may further comprise a controller 7 for controlling the operation of the sensor arrangement 1 (see also Figure 6 ).

[0032] Figure 2 Another embodiment of a sensor arrangement 1 is shown. The sensor arrangement can be as described with respect to Figure 1 As discussed above, however, the resonator array is a 1D array of LC circuits 5 that are in a coplanar arrangement rather than a coaxial arrangement. The substantially flat (planar) LC circuits 5 are arranged adjacent to each other, substantially all in the same plane as the plane of each LC circuit. The LC circuits may be arranged equidistant from each other along the axis between the sensor and the detector.

[0033] Apart from Figure 1 and Figure 2In an example embodiment of the present invention, it should be noted that the resonator array can follow a curved transmission path rather than a coaxial or coplanar path, as is suitable for integrating the array into an electrical device and for transmitting power and signals between the sensor 2 (e.g., at a high voltage) and a detector / power supply at a more external part of the electrical device (e.g., at a low voltage or lower voltage). In other words, the sensor can be arranged at a high potential and the detector and / or power supply are arranged at a low potential. In this configuration, the low voltage (LV) can be defined as ground potential. It should also be noted that the resonator array can alternatively be a 2D or 3D array, although 1D arrays are generally preferred. Further, it should be noted that the LC circuit can have any design and overall shape and does not need to be planar, although in some embodiments, planar LC circuits may be preferred because they take up little space and can be easily printed on an electrically insulating substrate.

[0034] Figure 3 An embodiment of an LC circuit 5 of a resonator array 4 is shown. The LC circuit may be formed, for example by printing, on or in an electrically insulating material 33 (e.g. a dielectric material 33), for example in the form of a film 32 (e.g. a flexible film that may facilitate integration of the array 4 in a crowded space of an electrical device).

[0035] In some embodiments, at least one sensor 2 is integrated with the resonator array 4, for example by being included in one of the LC circuits 5a of the array. The integrated sensor 2 may, for example, comprise a capacitor of a capacitive circuit C of an LC circuit 5a (e.g. the LC circuit farthest from the detector 3). The capacitor of the integrated sensor may then comprise a material 31 (e.g. a dielectric material), typically between its terminals, which material is sensitive to the characteristic x which it is arranged to sense. For example, if the characteristic is temperature, the material 31 may be or comprise a thermoelectric polymer or ceramic, or if the characteristic is pressure, the material may be or comprise a piezoelectric polymer. The capacitance of the capacitive circuit C is therefore affected by the characteristic x, giving a capacitance C(x), which may then be sensed and measured to give a measured value of x. The thickness of the membrane 32 may be of the order of tens of micrometers at most (referred to as thick film), and is preferably of the order of sub-micrometers (thin film technology). The surface area (footprint) of the resonator 4 is expected to be in the range of mm 2 to dm 2 within the range.

[0036] Note that a plurality of sensors 2 may be associated with the same array 4, in which case the plurality of sensors may be integrated with respective capacitive circuits C of the array 4 at different locations along the transmission path formed by the array.

[0037] Figure 4Transmissions within the sensor arrangement 1 during its operation are shown. The resonator array 4 has a fixed natural frequency f0 which is tuned to the natural frequency f of the sensor 2 which depends on the characteristic x of the environment. For example, the fixed natural frequency f0 of the resonator array 4 may be in the range of 10 kHz to 100 MHz. The fixed natural frequency f0 is typically tuned to the sensor unit frequency f(x) at some reference point x=x0, whereby changes in the characteristic x can propagate along the array 4 to be detected by the detector 3.

[0038] Thus, power 42 may be transmitted from electrical power source 6 to sensor 2 via array 4, and sensor signal 41 may be transmitted from sensor 2 to detector 3 via the same array 4. Thus, no antenna or electrical contact to the sensor is required, for example, to obtain signal 41 therefrom.

[0039] Figure 5 The schematically shown embodiment of a sensor arrangement 1 may be comprised in an electrical device 1 , such as an HV device.

[0040] Figure 6 A controller 7 of a sensor arrangement 1 is shown. The controller 7 includes a processing circuit 61 (e.g., a central processing unit (CPU)). The processing circuit 61 may include one or more processing units in the form of (multiple) microprocessors. However, other suitable devices with computing capabilities may be included in the processing circuit 61 (e.g., an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or a complex programmable logic device (CPLD)). The processing circuit 61 is configured to run in one or more computer programs or software (SW) 63 stored in a storage device 62 of one or more storage units (e.g., memory). The storage unit is considered to be a computer program product as discussed herein, which includes a computer executable component of SW 63 on a non-temporary computer readable medium, and may be, for example, in the form of a random access memory (RAM), a flash memory or other solid-state memory, or a hard disk, or a combination thereof. The processing circuit 61 may also be configured to store data in the storage device 62 as needed.

[0041] Embodiments of the present invention may be conveniently implemented using one or more conventional general or special purpose digital computers, computing devices, machines or microprocessors including one or more processors 61, memory and / or computer readable storage media 62 programmed according to the teachings of the present disclosure. As will be apparent to those skilled in the software arts, appropriate software 63 coding can be readily prepared by skilled programmers based on the teachings of the present disclosure.

[0042] Figure 7 is a flow chart of an embodiment of a method of the present invention. The method is for detecting a measured characteristic x in an environment of an electrical device. The method comprises wirelessly transmitting S1 power 42 from an electrical power source 6 to a sensor 2 in the environment via a resonator array 4 comprising an array of LC circuits 5, thereby powering the sensor. The method also comprises wirelessly transmitting S2 a signal 41 indicating a measured value of the characteristic x from the sensor 2 to the detector 3 via the resonator array 4.

[0043] Above the disclosure has mainly been described with reference to a few embodiments. However, as is readily appreciated by a person skilled in the art, other embodiments than the ones disclosed above are equally possible within the scope of the present disclosure, as defined by the appended claims.

Claims

1. A high voltage (HV) electrical device comprising a sensor arrangement (1), the sensor arrangement comprising: a sensor (2) configured to measure a characteristic of the electrical device; a detector (3) configured to receive a signal (41) from the sensor; Electrical power supply (6); as well as a resonator array (4), the resonator array comprising an array of LC circuits, the LC circuits being arranged equidistantly from one another and electrically isolated from one another along a transmission path between the sensor and the detector, such as an axis between the sensor and the detector, and the resonator array being configured to wirelessly transmit power (42) from the electrical power source (6) to the sensor and to wirelessly transmit sensor signals (41) from the sensor to the detector, wherein the sensor (2) is integrated with the resonator array (4), and wherein the integrated sensor (2) comprises a capacitor (C) of an LC circuit of the resonator array (4).

2. The electrical device according to claim 1, wherein: The resonator array (4) has a fixed natural frequency (f0) which is tuned to a natural frequency (f) of an environment-dependent characteristic (x) of the sensor (2).

3. The electrical device according to claim 2, wherein: The fixed natural frequency (f0) of the resonator array (4) is in the range of 10 kHz to 100 MHz.

4. The electrical device according to any one of claims 1 to 3, wherein: The sensor is arranged at a high potential and the detector and / or the power supply is arranged at a low potential.

5. The electrical device according to any one of claims 1 to 3, wherein: The detector (3) comprises an impedance meter.

6. The electrical device according to claim 5, wherein: The impedance meter is an impedance analyzer.

7. The electrical device according to claim 1, wherein: The capacitor (C) comprises a dielectric material which is sensitive to a characteristic (x) of the electrical device.

8. The electrical device according to claim 7, wherein: The characteristic of the electrical device is temperature, and the dielectric material is a thermoelectric polymer or a ceramic.

9. The electrical device according to claim 7, wherein: The characteristic of the electrical device is pressure, and the dielectric material is a piezoelectric polymer.

10. The electrical device according to any one of claims 1 to 3, wherein: Each LC circuit (5) of the resonator array (4) is printed on an electrically insulating film (32).

11. The electrical device according to claim 10, wherein: The electrical insulating film is a dielectric material.

12. The electrical device according to any one of claims 1 to 3, wherein: The resonator array (4) comprises a plurality of planar LC circuits (5) coaxially arranged at a preset distance (D) from each other.

13. The electrical device according to any one of claims 1 to 3, wherein: The resonator array (4) comprises a plurality of coplanar flat LC circuits (5) arranged side by side.

14. The electrical device according to any one of claims 1 to 3, wherein: The characteristic (x) of the HV environment is any one of the group of characteristics consisting of: Temperature, pressure, acceleration, humidity, acidity and oxygen levels.

15. The electrical device according to claim 14, wherein: The characteristics of the HV environment are temperature or pressure.

16. The electrical device according to claim 15, wherein: A characteristic of the HV environment is temperature.

17. The electrical device according to any one of claims 1 to 3, wherein: The electrical device is a transformer.

18. A method for detecting a measured characteristic (x) in a high voltage (HV) electrical device, comprising: wirelessly transmitting power (42) from an electrical power source (6) to a sensor (2) via an array of resonators (4), thereby powering the sensor, wherein the array of resonators comprises an array of LC circuits arranged equidistantly from one another and electrically isolated from one another along a transmission path between the sensor (2) and a detector (3), such as an axis between the sensor and the detector; and wirelessly transmitting a signal (41) indicative of a measured value of the characteristic (x) from the sensor (2) to the detector (3) via the resonator array (4), wherein the sensor (2) is integrated with the resonator array (4), and wherein the integrated sensor (2) comprises a capacitor (C) of an LC circuit of the resonator array (4).

19. A computer program product comprising computer executable components for causing the controller (7) to perform the method according to claim 18 when the computer executable components are run on a processing circuit (61) included in the controller.

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