Surface acoustic wave wireless temperature measuring device for high-voltage power cabinet

Abstract

The utility model discloses a surface acoustic wave wireless temperature measuring device for a high-voltage electric power cabinet, which comprises a temperature sensor arranged in the high-voltage electric power cabinet, the temperature sensor is an SAW sensor and is integrally packaged in a ceramic shell with a metal shielding layer, and the surface of the ceramic shell is coated with a conducting layer and is grounded. The bottom of the ceramic housing is fixed on the surface of a to-be-tested high-voltage conductor through an insulating spacer. The signal radiation direction of the first antenna faces a preset signal window of the high-voltage power cabinet; the temperature measuring device further comprises a wireless reader-writer which is fixedly installed outside a preset signal window of the high-voltage power cabinet and is aligned with the antenna signal radiation direction of the SAW sensor in the cabinet. According to the invention, the surface of the ceramic housing is coated with the conductive layer, and the conductive layer is grounded, so that the interference of partial discharge on SAW signals is eliminated; the wireless reader-writer with the adjustable transmitting power is arranged to be matched with the shielding attenuation characteristic of the high-voltage power cabinet, so that the penetrating power of the SAW signal is conveniently ensured, and the temperature in the high-voltage power cabinet is effectively monitored.

Description

TECHNICAL FIELD

[0001] The utility model relates to temperature measurement technical field, concretely relates to a surface acoustic wave wireless temperature measuring device for high voltage power cabinet. BACKGROUND

[0002] With the continuous development and increasing complexity of the power system, the reliability and safety of power equipment are paid more and more attention, especially the key parts in high voltage power cabinet, such as busbar connection, circuit breaker contact, etc. These parts are prone to local overheating due to poor contact, overload and other problems because they are in a high voltage and strong electromagnetic interference environment for a long time. If the overheating problem is not discovered in time, it may cause a fire or equipment failure, thereby causing great safety hazards. Therefore, accurately and timely monitoring the temperature inside the power cabinet, especially in high voltage power equipment, has become a key task to ensure the stable operation and safety of the power system.

[0003] Currently, in the traditional temperature measurement method, if a wired temperature measurement sensor such as a thermocouple and an optical fiber sensor is used, the wired temperature measurement sensor needs to be installed in the high voltage power cabinet and wired in the high voltage power cabinet, the installation process is complex, and there is an insulation risk; if an infrared temperature measurement sensor is used, the cabinet of the high voltage power cabinet is shielded; if a SAW wireless temperature measurement sensor with passive advantage is used, the SAW wireless temperature measurement sensor is easily disturbed by corona discharge in a high voltage environment, and the metal cabinet seriously shields the wireless signal, so effective temperature monitoring cannot be performed. SUMMARY

[0004] Therefore, the utility model embodiment provides a surface acoustic wave wireless temperature measuring device for high voltage power cabinet to solve the problem that the existing SAW wireless temperature measurement sensor is easily disturbed by corona discharge in a high voltage environment, and the metal cabinet seriously shields the wireless signal, so effective temperature monitoring cannot be performed.

[0005] In order to achieve the above purpose, the utility model embodiment provides the following technical scheme:

[0006] A surface acoustic wave wireless temperature measuring device for high voltage power cabinet, comprising a temperature sensor arranged in the high voltage power cabinet; characterized in that the temperature sensor is a SAW sensor, the temperature sensor is integrally composed of a piezoelectric substrate, an interdigital transducer, a reflection grating and a first antenna, and is integrally packaged in a ceramic shell with a metal shielding layer, the surface of the ceramic shell is coated with a conductive layer and grounded, and the bottom of the ceramic shell is fixed to the surface of the high voltage conductor to be measured through an insulating gasket; the first antenna adopts a microstrip patch antenna, and the signal radiation direction of the first antenna is directed to the observation window or the preset signal window of the high voltage power cabinet;

[0007] The device further comprises a wireless reader with adjustable transmitting power, which is fixedly installed outside the observation window or the preset signal window of the high-voltage power cabinet and is aligned with the antenna signal radiation direction of the SAW sensor in the cabinet.

[0008] In the above scheme, the interdigital transducer and the reflective grating are arranged on the piezoelectric substrate, and the first antenna is mounted on the PAD of the reflective grating.

[0009] In the above scheme, the number of the reflective gratings in the temperature sensor is at least one, and the first antenna is mounted on the PAD of each reflective grating, and the first antenna is a dipole structure etched on the PAD.

[0010] In the above scheme, the second antenna of the wireless reader is installed outside the observation window or the preset signal window of the high-voltage power cabinet, and the second antenna is directed towards the radiation direction of the first antenna.

[0011] In the above scheme, the device further comprises a processor.

[0012] The processor is connected with the wireless reader.

[0013] The temperature sensor transmits a temperature measurement signal to the wireless reader, the wireless reader decodes the temperature measurement signal to obtain a decoded temperature measurement signal, and the processor calculates the decoded temperature measurement signal by frequency offset to obtain temperature data measured by the temperature sensor.

[0014] In the above scheme, the piezoelectric substrate is made of quartz, and the surface of the piezoelectric substrate is coated with a silica gel temperature sensitive layer.

[0015] In the above scheme, the metal shielding layer on the ceramic shell is an aluminum oxide shielding layer.

[0016] In the above scheme, the wireless reader uses a wideband sweep signal, and the working frequency band of the wireless reader is 2.4GHz-2.5GHz.

[0017] In the above scheme, the wireless reader uses frequency hopping spread spectrum technology, and the working frequency band is 915MHz.

[0018] In the above scheme, the transmitting power of the wireless reader is 15dBm.

[0019] In the above scheme, the transmitting power of the wireless reader is 15dBm.

[0020] The utility model discloses at least the following beneficial effects:

[0021] The utility model provides a kind of for high voltage power cabinet's surface acoustic wave wireless temperature measuring device, including the temperature sensor being set in high voltage power cabinet, temperature sensor is SAW sensor, temperature sensor is integrally constituted by piezoelectric substrate, interdigital transducer, reflection grid and first antenna, and integrally encapsulated in the ceramic shell with metal shielding layer, ceramic shell surface is coated with conducting layer and ground, ceramic shell bottom is fixed on the surface of the high voltage conductor to be measured by insulating gasket;First antenna uses microstrip patch antenna, the signal radiation direction of antenna is towards the observation window or preset signal window of high voltage power cabinet;In addition, the temperature measuring device further includes adjustable transmitting power wireless reader, wireless reader is fixedly installed in the observation window or preset signal window outside of high voltage power cabinet, and is aligned with the antenna signal radiation direction of SAW sensor in cabinet.In the present application, by coating conducting layer on the surface of ceramic shell and grounding, the interference of partial discharge to SAW signal can be eliminated;And by setting adjustable transmitting power wireless reader, the shielding attenuation characteristics of high voltage power cabinet can be matched, so as to ensure the penetration of SAW signal, and then realize effective monitoring to the temperature in high voltage power cabinet, provide strong guarantee for the safe operation of power equipment. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the prior art and the utility model, the drawings needed to be used in the following description of the prior art and the utility model embodiment will be briefly introduced. Obviously, the drawings in the following description are only exemplary, and those skilled in the art can also obtain other drawings according to the provided drawings without creating creative labor.

[0023] The structure, proportion, size and the like shown in the specification are only used to cooperate with the content disclosed in the specification for understanding and reading by those skilled in the art, and are not used to limit the limiting conditions that can be implemented by the utility model. Any modification of structure, change of proportion relationship or adjustment of size, which does not affect the effects and purposes that can be produced by the utility model, should still fall within the scope covered by the technical content disclosed by the utility model.

[0024] Figure 1 A structure schematic view of the surface acoustic wave wireless temperature measuring device for high voltage power cabinet and high voltage power cabinet provided by the utility model embodiment is provided;

[0025] Figure 2 A structure schematic view of the temperature sensor provided by the utility model embodiment is provided;

[0026] Figure 3 A circuit principle block diagram of the temperature sensor provided by the utility model embodiment is provided;

[0027] Figure 4 The application scenario schematic diagram of the temperature sensor is provided for the embodiment of the utility model. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical scheme and advantages of the present application more clear and understandable, the present application will be further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not to limit the present application.

[0029] In the description of the utility model, unless otherwise specified, the meaning of "multiple" is two or more than two. The terms "first", "second", "third", "fourth" and the like (if any) in the specification and claims of the utility model and the above-mentioned drawings are intended to distinguish the objects referred to. For the scheme with time sequence flow, this kind of term expression method should not be understood as describing a specific order or sequence, and for the scheme of device structure, this kind of term expression method does not distinguish importance, position relationship and the like.

[0030] In addition, the terms "include", "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not have to be limited to only those steps or units explicitly listed, but can also include other steps or units inherent to these processes, methods, products or devices, or steps or units added based on further optimization schemes of the utility model concept.

[0031] As shown in Figure 1 and Figure 2 A surface acoustic wave wireless temperature measuring device for a high-voltage power cabinet, comprising a temperature sensor 2 arranged in a high-voltage power cabinet 1; characterized in that the temperature sensor 2 is a SAW sensor, the temperature sensor 2 is integrally composed of a piezoelectric substrate 21, an interdigital transducer 22, a reflection grating 23 and a first antenna 24, and is integrally packaged in a ceramic shell with a metal shielding layer, the surface of the ceramic shell is coated with a conductive layer and is grounded, and the bottom of the ceramic shell is fixed to the surface of the high-voltage conductor 11 to be measured through an insulating gasket; the first antenna 24 adopts a microstrip patch antenna, and the signal radiation direction of the antenna is directed to the observation window 12 or the preset signal window of the high-voltage power cabinet 1.

[0032] The device further comprises a wireless reader / writer 3 with adjustable transmitting power, which is fixedly installed outside the observation window 12 or the preset signal window of the high-voltage power cabinet 1, and is aligned with the antenna signal radiation direction of the SAW sensor in the cabinet.

[0033] Among them, the surface acoustic wave (SAW) temperature sensor is a passive wireless sensor based on surface acoustic wave technology. The SAW sensor is usually composed of a piezoelectric substrate 21, an interdigital transducer 22, a reflective grating 23 and a first antenna 24.

[0034] It should be noted that the piezoelectric substrate 21 is the core basic material of the SAW sensor, and its main function is to convert electrical energy into mechanical energy (surface acoustic wave) and then convert mechanical energy into electrical energy.

[0035] When an electric field is applied to the piezoelectric substrate 21, the piezoelectric substrate 21 will produce mechanical deformation, thereby exciting surface acoustic waves; conversely, when the surface acoustic wave propagates on the piezoelectric substrate 21, it will produce an electric field due to mechanical deformation. The mutual conversion of electrical and mechanical energy is the basis for the operation of the SAW sensor.

[0036] The commonly used material of the piezoelectric substrate 21 is quartz crystal, lithium niobate, lithium tantalate and other materials with good piezoelectric properties and temperature stability.

[0037] It should be noted that the interdigital transducer 22 is a key component of the SAW sensor, which is used to excite and receive surface acoustic waves.

[0038] The interdigital transducer (IDT) is composed of a plurality of parallel metal fingers. When a high-frequency electrical signal is applied, the IDT will produce an alternating electric field on the surface of the piezoelectric substrate, thereby exciting surface acoustic waves. Conversely, when the surface acoustic wave propagates to the IDT, it will generate induced charges between the fingers, forming an electrical signal output.

[0039] It should be noted that the reflective grating 23 is used to reflect the surface acoustic wave to form a standing wave, thereby realizing the delay and modulation of the signal.

[0040] The reflective grating 23 is composed of a series of periodically arranged metal strips. When the surface acoustic wave propagates to the reflective grating, it will be reflected back to the IDT direction. By designing the period and number of the reflective grating, the phase and amplitude of the reflected wave can be controlled, thereby realizing the modulation of the signal.

[0041] The first antenna 24 is used to realize the wireless communication between the SAW sensor and the wireless reader 3.

[0042] The first antenna 24 receives the radio frequency signal from the wireless reader 3 and transmits it to the IDT to excite the surface acoustic wave. At the same time, the first antenna 24 also sends the modulated signal generated by the IDT back to the wireless reader 3.

[0043] Among them, the surface of the ceramic shell is coated with a conductive layer, which means that the surface of the ceramic shell is covered with a layer of material with conductive properties, so that it has the function of grounding, to realize electromagnetic shielding, static protection or signal transmission and other functions.

[0044] It should be noted that the conductive layer is usually made of metal materials (such as gold, silver, copper, molybdenum, etc.) or conductive composite materials.

[0045] In the ceramic shell, the conductive layer is often used in electroplated areas such as grounding pads, signal pads or metal sealing rings to realize grounding and signal transmission. Through the conductive coating, the ceramic shell can better adapt to high-frequency signal transmission and reduce electromagnetic interference.

[0046] In this embodiment, the piezoelectric substrate 21, the interdigital transducer 22, the reflective grating 23 and the first antenna 24 of the temperature sensor 2 are integrally packaged in a ceramic shell with a metal shielding layer, and the withstand voltage of the ceramic shell is ≥10kV, so as to realize the high-voltage resistant packaging of the temperature sensor 2. In addition, the surface of the ceramic shell is covered with a fluorinated silicone gel layer to facilitate anti-corona discharge.

[0047] Among them, the insulating gasket is an epoxy insulating gasket.

[0048] It should be noted that the insulating gasket at the bottom of the ceramic shell is fixed on the surface of the high-voltage conductor 11 to be measured by an insulating buckle or magnetic attraction, so as to avoid direct contact with the high-voltage conductor 11 to be measured, and at the same time, the installation angle of the temperature sensor 2 can be adjusted to make the first antenna 24 of the temperature sensor 2 face the observation window 12 or the preset signal window of the high-voltage power cabinet 1.

[0049] In this embodiment, the high-voltage conductor 11 to be measured is a busbar or a contact.

[0050] Among them, the wireless reader / writer 3 adopts frequency hopping spread spectrum (FHSS) technology to avoid the pulse interference frequency band generated by the switch operation in the high-voltage power cabinet.

[0051] The utility model provides a kind of for high voltage power cabinet's surface acoustic wave wireless temperature measuring device, including the temperature sensor being set in high voltage power cabinet, temperature sensor is SAW sensor, temperature sensor is by piezoelectric substrate, interdigital transducer, reflection grating and first antenna integration, and integrally encapsulated in the ceramic shell with metal shielding layer, ceramic shell surface is coated with conducting layer and ground, ceramic shell bottom is fixed on the surface of the high voltage conductor to be measured by insulating gasket;First antenna uses microstrip patch antenna, the signal radiation direction of antenna is towards the observation window or preset signal window of high voltage power cabinet;In addition, the temperature measuring device further includes adjustable transmitting power wireless reader-writer, wireless reader-writer is fixedly installed in the observation window or preset signal window outside of high voltage power cabinet, aligns the antenna signal radiation direction of SAW sensor in cabinet.In the present application, by coating conducting layer on the surface of ceramic shell and ground, the interference of partial discharge to SAW signal can be eliminated;And by setting adjustable transmitting power wireless reader-writer, the shielding attenuation characteristics of high voltage power cabinet can be matched, so as to ensure the penetrating power of SAW signal, and then realize the effective monitoring to the temperature in high voltage power cabinet, provide strong guarantee for the safe operation of power equipment.

[0052] As Figure 2 Shown in the present embodiment, interdigital transducer 22 and reflection grating 23 are arranged on piezoelectric substrate 21, and first antenna 24 is installed on PAD 231 of reflection grating 23.

[0053] As Figure 2 Shown in the present embodiment, the number of reflection grating 23 in temperature sensor 2 is at least one, and first antenna 24 is installed on PAD 231 of each reflection grating 23, and first antenna 24 is a dipole structure etched on PAD 231.

[0054] As Figure 1 Shown in the present embodiment, second antenna 31 on wireless reader-writer 3 is installed outside the observation window 12 or preset signal window of high voltage power cabinet 1, and second antenna 31 is towards the radiation direction of first antenna 24.Second antenna 31 extends into high voltage power cabinet 1 through observation window 12.

[0055] In the present embodiment, the device further includes a processor; the processor is connected with wireless reader-writer 3;

[0056] Wherein, temperature sensor 2 transmits temperature measurement signal to wireless reader-writer 3, wireless reader-writer 3 decodes temperature measurement signal to obtain decoded temperature measurement signal, and processor calculates decoded temperature measurement signal through frequency offset to obtain temperature data measured by temperature sensor 2.

[0057] In the present embodiment, piezoelectric substrate 21 is quartz material, and piezoelectric substrate 21 is coated with silica gel temperature sensitive layer on the surface.

[0058] In the embodiment, the metal shielding layer on the ceramic shell is an alumina shielding layer.

[0059] In the embodiment, the wireless reader / writer 3 adopts a wideband sweep signal, and the working frequency band of the wireless reader / writer 3 is 2.4GHz-2.5GHz.

[0060] In the embodiment, the wireless reader / writer 3 adopts frequency hopping spread spectrum technology, and the working frequency band is 915MHz.

[0061] In the embodiment, the transmitting power of the wireless reader / writer 3 is 15dBm.

[0062] Figure 4 An application scenario schematic diagram of the temperature sensor is provided in the embodiment of the utility model. As shown in the figure, the temperature collector comprises a wireless reader / writer 3 and a processor, a plurality of temperature sensors 2 can share one temperature collector, and the processor in the temperature collector transmits the temperature data measured by the temperature sensor 2 to a monitoring computer through a communication module. Figure 4

[0063] The monitoring computer is further connected with a terminal alarm module, so as to trigger the sound-light alarm of the cabinet body when the temperature corresponding to the temperature data is out of limit, and synchronously upload to the power monitoring system.

[0064] In the embodiment, a plurality of temperature sensors 2 can share the same wireless reader / writer 3, and when a plurality of temperature sensors 2 share the same wireless reader / writer 3, signal collision can be reduced through time slot allocation, and the embodiment is suitable for the scene of multi-contact monitoring.

[0065] The surface acoustic wave wireless temperature measuring device provided in the embodiment has high pressure adaptability and insulation safety, and has penetration guarantee. Specifically, the voltage resistance grade of the temperature sensor 2 is ≥10kV, which can be directly installed on the live busbar to have high pressure adaptability; the insulation resistance between the temperature sensor 2 and the high-voltage conductor 11 to be measured is >100MΩ, which meets the safety standard of power equipment to have insulation safety; the device adopts 915MHz frequency band with directional antenna, and the signal attenuation through the metal cabinet is ≤3d, so as to guarantee the penetration of the device.

[0066] When the surface acoustic wave wireless temperature measuring device provided in the embodiment is actually measured in a 10kV high-voltage cabinet, the signal receiving success rate is >99% when the distance between the temperature sensor 2 and the wireless reader / writer 3 is 3m, and the temperature measurement error is ±1℃.

[0067] ​It should be noted that the surface acoustic wave wireless temperature measuring device provided in the embodiment solves the problems of high insulation risk, poor signal penetration of the traditional sensor, and wireless temperature measurement in a strong electromagnetic shielding environment in the cabinet through high-voltage resistant packaging, directional antenna design, and frequency hopping anti-interference technology, realizes passive wireless temperature monitoring of key parts in a strong electromagnetic shielding environment, has good monitoring effect, and significantly improves the operation safety of high-voltage power equipment.

[0068] The surface acoustic wave wireless temperature measuring device provided in the embodiment can not only be used for non-contact temperature monitoring of key parts (such as busbar connection and circuit breaker contact) in a high-voltage power cabinet, but also can be used for temperature measurement in other temperature measurement scenes requiring high voltage, strong electromagnetic interference, and airtight environment.

[0069] The above embodiment only expresses the specific implementation manner of the utility model, and the description is relatively specific and detailed, but it should not be understood as a limitation on the patent range of the utility model. It should be noted that for ordinary skilled persons in the art, without departing from the concept of the utility model, a number of modifications and improvements can be made, which belong to the protection range of the utility model.

Claims

1. A surface acoustic wave wireless temperature measuring device for a high-voltage power cabinet, comprising a temperature sensor (2) arranged in a high-voltage power cabinet (1); characterized in that, The temperature sensor (2) is a SAW sensor, which is integrally formed by a piezoelectric substrate (21), an interdigital transducer (22), a reflective grating (23) and a first antenna (24), and is integrally packaged in a ceramic shell with a metal shielding layer, the surface of the ceramic shell is coated with a conductive layer and grounded, and the bottom of the ceramic shell is fixed to the surface of the high-voltage conductor (11) to be measured by an insulating gasket; the first antenna (24) adopts a microstrip patch antenna, and the signal radiation direction of the first antenna is directed to the observation window (12) or the preset signal window of the high-voltage power cabinet (1). The device further comprises a wireless reader / writer (3) with adjustable transmission power, which is fixedly installed outside the observation window (12) or the preset signal window of the high-voltage power cabinet (1) and is aligned with the antenna signal radiation direction of the SAW sensor in the cabinet.

2. The surface acoustic wave wireless temperature measuring device for high voltage power cabinet according to claim 1, characterized in that, The interdigital transducer (22) and the reflective grating (23) are arranged on the piezoelectric substrate (21), and the first antenna (24) is installed on the PAD (231) of the reflective grating (23).

3. The surface acoustic wave wireless temperature measuring device for high voltage power cabinet according to claim 1, characterized in that, The number of the reflective gratings (23) in the temperature sensor (2) is at least one, and the first antenna (24) is installed on the PAD (231) of each reflective grating (23), and the first antenna (24) is a dipole structure etched on the PAD (231).

4. The surface acoustic wave wireless temperature measuring device for high voltage power cabinet according to claim 1, characterized in that, The second antenna (31) of the wireless reader / writer (3) is installed outside the observation window (12) or the preset signal window of the high-voltage power cabinet (1), and the second antenna (31) is directed to the radiation direction of the first antenna (24).

5. The surface acoustic wave wireless temperature measuring device for high voltage power cabinet according to claim 1, characterized in that, The device further comprises a processor; The processor is connected with the wireless reader / writer (3); The temperature sensor (2) transmits a temperature measurement signal to the wireless reader / writer (3), the wireless reader / writer (3) decodes the temperature measurement signal to obtain a decoded temperature measurement signal, and the processor calculates the decoded temperature measurement signal by frequency offset to obtain temperature data measured by the temperature sensor (2).

6. The surface acoustic wave wireless temperature measuring device for high voltage power cabinet according to claim 1, characterized in that, The piezoelectric substrate (21) is made of quartz, and the surface of the piezoelectric substrate (21) is coated with a silica gel temperature sensitive layer.

7. The surface acoustic wave wireless temperature measuring device for high voltage power cabinet according to claim 1, characterized in that, The metal shielding layer on the ceramic shell is an aluminum oxide shielding layer.

8. The surface acoustic wave wireless temperature measuring device for high voltage power cabinet according to claim 1, characterized in that, The wireless reader / writer (3) adopts a wideband sweep signal, and the working frequency band of the wireless reader / writer (3) is 2.4GHz-2.5GHz.

9. The surface acoustic wave wireless temperature measuring device for high voltage power cabinet according to claim 1, characterized in that, The wireless reader / writer (3) adopts frequency hopping spread spectrum technology, and the working frequency band is 915MHz.

10. The surface acoustic wave wireless temperature measuring device for high voltage power cabinet according to claim 1, characterized in that, The transmission power of the wireless reader / writer (3) is 15dBm.

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