Capacitive voltage transformer on-line wireless monitoring device, system and method

Abstract

The invention relates to an on-line wireless monitoring technology for a capacitive voltage transformer, which utilizes wireless energy collection to serve as an on-line wireless monitoring device function, and obtains capacitance value change through induction current output by a current sensor sleeved on a power transmission line of the capacitive voltage transformer. The operation state of the capacitive voltage transformer can be known by monitoring the capacitance value, a voltage signal representing the change of the capacitance value is converted into a frequency signal by using the voltage-controlled oscillator, and the frequency signal carrying the operation state information of the capacitive voltage transformer is sent to a far-end transceiver through the antenna. By monitoring the change of the output frequency of the voltage-controlled oscillator caused by the change of the capacitance value of the capacitive voltage transformer, the online monitoring of the capacitive voltage transformer is realized, and the online monitoring device has the characteristics of high monitoring precision and low false alarm rate. A wireless monitoring mode is adopted, and the problems of difficult wiring on an operation site, high operation danger coefficient and difficult later maintenance are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of transformer status monitoring, and in particular to an online wireless monitoring device, system and method for a capacitor voltage transformer. Background Art

[0002] Operational experience shows that capacitor voltage transformers (CVTs) have numerous defects, high failure rates, and require extensive maintenance. If these defects are not promptly addressed, they can cause explosions. In actual operation, CVTs can experience not only visible faults such as oil leaks and unusual noises, but also internal faults such as capacitor breakdown and intermediate transformer failures. These operational defects are common and difficult to detect, causing CVT measurement errors to exceed reasonable limits, posing a serious threat to the safe operation of the power grid.

[0003] Capacitor units account for the majority of CVT defects. If some capacitor elements and most electromagnetic unit components are damaged, the secondary output voltage will change accordingly. Currently, there are few strategies for monitoring the operating status of capacitive voltage transformers, mainly infrared diagnosis. However, the existing infrared diagnosis method is limited in that it is only effective when the product is severely overheated and requires other auxiliary methods for fault diagnosis, which has certain limitations. Secondly, it requires offline power outage inspections and cannot be monitored online. Its main disadvantages are high workload and long time consumption. In order to detect CVT abnormalities early and avoid equipment accidents, it is necessary to implement CVT online monitoring to detect abnormalities in a timely manner and issue alarms. Summary of the Invention

[0004] In order to solve at least one technical problem in the above-mentioned prior art, the present invention provides an online wireless monitoring device, system and method for a capacitor voltage transformer.

[0005] A first aspect of the present invention provides an online wireless monitoring device for a capacitor voltage transformer, comprising: a current sensor, a current-voltage converter, a voltage-controlled oscillator, a controller, an energy harvester, a modulation element, and an antenna;

[0006] The current sensor, the current-voltage converter, the voltage-controlled oscillator, the modulation element and the antenna are electrically connected in sequence;

[0007] The antenna, energy harvester, controller and modulation element are electrically connected in sequence;

[0008] The current sensor is mounted on the transmission line of the capacitor voltage transformer and is configured to detect the induced current on the transmission line;

[0009] The current-to-voltage converter is configured to convert the current generated by the current sensor into a voltage;

[0010] The voltage controlled oscillator is configured to output a frequency corresponding to the voltage output by the current-voltage converter.

[0011] Optionally, the antenna is configured to receive a downlink microwave signal having a first frequency and send an uplink microwave signal having a second frequency, where the first frequency is different from the second frequency.

[0012] Optionally, the energy harvester is configured to convert the downlink microwave signal coupled by the antenna into direct current and store the direct current to provide power for the controller.

[0013] Optionally, the controller is configured to have built-in tag information, and to operate under the power provided by the energy harvester, and output high and low level signals representing the tag information to the modulation element.

[0014] Optionally, the modulation element is a switching element.

[0015] Optionally, the current sensor adopts an open-close through-hole structure.

[0016] A second aspect of the present invention provides an online wireless monitoring device for a capacitor voltage transformer, comprising: a transceiver and a plurality of the above-mentioned online wireless monitoring devices for a capacitor voltage transformer;

[0017] The transceiver is configured to broadcast a downlink microwave signal with a first frequency and containing specific tag information into free space, and receive an uplink microwave signal with a second frequency and carrying capacitor voltage transformer operating status data sent by a capacitor voltage transformer online wireless monitoring device with built-in specific tag information, and parse the capacitor voltage transformer operating status data.

[0018] A third aspect of the present invention provides an online wireless monitoring method for a capacitor voltage transformer, comprising:

[0019] Step 1: The transceiver 411 broadcasts a downlink microwave signal having a first frequency and containing specific tag information into free space;

[0020] Step 2: Several online wireless monitoring devices located within the effective communication area of the transceiver 411 receive the downlink microwave signal sent by the transceiver 411;

[0021] Step 3: The online wireless monitoring device with the aforementioned specific tag information embedded therein sends an uplink microwave signal with a second frequency carrying the operating status data of the capacitor voltage transformer to the transceiver 411;

[0022] Step 4: The transceiver 411 receives the uplink microwave signal and parses it to obtain the operating status data of the capacitor voltage transformer.

[0023] Optionally, in step 3, the following sub-steps may be included:

[0024] Step 3.1: After receiving the downlink microwave signal from the transceiver 411, the online wireless monitoring device with the aforementioned specific tag information rectifies the downlink microwave signal and converts it into direct current.

[0025] Step 3.2: The controller 313 operates under the power supply of DC and generates high and low level control signals containing the aforementioned specific tag information;

[0026] Step 3.3: The modulation element 314 responds to the high and low level control signals and performs on-off operations on the signal with the second frequency generated by the voltage controlled oscillator 312; wherein the signal with the second frequency generated by the voltage controlled oscillator 312 represents the operating status data of the capacitor voltage transformer;

[0027] In step 3.4, the antenna 316 couples and outputs the signal with the second frequency in the on state to form an uplink microwave signal, and sends the signal to the transceiver 411 .

[0028] Compared with the prior art, the present invention has at least the following beneficial effects:

[0029] Because the uplink signal received by the transceiver is at a different frequency than the downlink signal it transmits, the isolation requirements between the transceiver's transmit and receive channels are significantly reduced. When the transmission and reception frequencies are the same, the transmitted downlink signal is easily reflected by the surrounding environment, multipath interference, and other effects and re-enters the transceiver's receive channel, which constitutes interference. However, when the transmission and reception frequencies are different, these interference signals do not interfere with the receive channel. Therefore, the different-frequency transmission and reception system has stronger anti-interference capabilities. Compared with the same-frequency transmission and reception system, the different-frequency transmission and reception system can use higher transmit power, thereby extending the wireless working range.

[0030] This solution's online wireless monitoring method is inherently passive and inherently safe. Furthermore, it eliminates the need for power outages, simplifies installation, and enables real-time monitoring, improving monitoring efficiency and reducing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A schematic structural diagram of an online wireless monitoring device / system for a capacitor voltage transformer provided in one embodiment of the present invention;

[0032] Explanation of the reference numerals: 111 - capacitive voltage transformer; 211 - current sensor; 311 - current-voltage converter; 312 - voltage-controlled oscillator; 313 - controller; 314 - modulation element; 315 - energy harvester; antenna - 316; 411 - transceiver. DETAILED DESCRIPTION

[0033] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0034] Figure 1 The figure shows an online wireless monitoring device for a capacitor voltage transformer according to an embodiment of the present invention, which includes a current sensor 211, a current-voltage converter (i.e., an IV converter) 311, a voltage-controlled oscillator (VCO) 312, a controller 313, an energy harvester 315, a modulation element 314, and an antenna 316.

[0035] In some embodiments, the capacitive voltage transformer 111 is composed of a plurality of capacitor units. For example, Figure 1 C1 is used to represent several capacitor units.

[0036] The current sensor 211 is mounted on the transmission line of the capacitor voltage transformer 111 and obtains the capacitance value change by detecting the induced current on the transmission line. The operating status of the capacitor voltage transformer can be understood by monitoring the capacitance value.

[0037] In some embodiments, the current sensor 211 can be an open-close current sensor with an open-close through-hole structure, which does not require disconnecting the measured transmission line, facilitating installation and measurement. The current sensor 211 can be any suitable current sensor, such as a zero-flux closed-loop current sensor.

[0038] The IV converter 311 converts the current generated by the current sensor 211 into a voltage; the IV converter can be any suitable device or circuit that can achieve the current-voltage conversion function, and its specific structure is not limited.

[0039] The voltage-controlled oscillator 312 outputs a frequency corresponding to the voltage output by the IV converter 311. The voltage-controlled oscillator 312 can be any suitable device or circuit that can achieve frequency variation with voltage, including but not limited to an LC voltage-controlled oscillator, an RC voltage-controlled oscillator, or a crystal voltage-controlled oscillator, and its specific structure is not limited.

[0040] Through the above configuration, when the capacitance value of the capacitor voltage transformer changes, the output frequency of the voltage-controlled oscillator 312 also changes accordingly, thereby enabling online monitoring of the capacitor voltage transformer.

[0041] Antenna 316 is used to receive a downlink microwave signal having a first frequency transmitted by a remote transceiver 411, and simultaneously transmit an uplink microwave signal having a second frequency to the remote transceiver 411, the first frequency being different from the second frequency. In other words, the online wireless monitoring device of the present invention is a different-frequency transceiver. This arrangement offers at least the following advantages: First, because the uplink signal received by the transceiver is at a different frequency than the downlink signal transmitted, the isolation requirements between the transceiver's transmit and receive channels are significantly reduced. Second, when the transmission and reception frequencies are the same, the transmitted downlink signal is easily re-entered into the transceiver's receive channel by reflections from the surrounding environment, multipath interference, and other effects. This portion of the signal constitutes interference. However, when the transmission and reception frequencies are different, this interference signal does not interfere with the receive channel. Therefore, the different-frequency transmission and reception system has stronger anti-interference capabilities. Third, compared to the same-frequency transmission and reception system, the different-frequency transmission and reception system can use higher transmission power, thereby extending the wireless working range.

[0042] In some embodiments, the first frequency and the second frequency are both carrier frequencies or center frequencies. In principle, the first frequency and the second frequency can be any suitable frequencies. For example, the first frequency is 450 MHz and the second frequency is 414 MHz. The above is merely an example and should not be construed as limiting the operating frequency band of the present invention.

[0043] The energy harvester 315 is used to convert the downlink microwave signal coupled by the antenna 314 into direct current and store the direct current, so as to provide the controller 313 with the power required for its operation.

[0044] The controller 313 has built-in tag information and operates under the power provided by the energy harvester 315 , outputting high and low level signals representing the tag information to the modulation element 314 .

[0045] Modulation element 314 amplitude modulates the signal output by voltage-controlled oscillator 312. For example, modulation element 314 is a switching element, typically a field-effect transistor. When the controller outputs a high level, modulation element 314 is in an on state, allowing the signal at the second frequency output by voltage-controlled oscillator 312 to reach antenna 316 and form an uplink microwave signal via antenna 316. When the controller outputs a low level, modulation element 314 is in an off state, preventing the signal at the second frequency output by voltage-controlled oscillator 312 from reaching antenna 316 and thus forming an uplink microwave signal.

[0046] like Figure 1 As shown, the present invention further provides an embodiment of an online wireless monitoring system for a capacitor voltage transformer, which includes a transceiver 411 and several of the aforementioned online wireless monitoring devices.

[0047] In some embodiments, the transceiver 411 broadcasts a downlink microwave signal having a first frequency and containing specific tag information into free space.

[0048] In some embodiments, multiple online wireless monitoring devices located within the effective communication area of transceiver 411 receive the downlink microwave signal transmitted by transceiver 411. In particular, only the online wireless monitoring devices with built-in corresponding specific tag information respond to receiving the downlink microwave signal by transmitting an uplink microwave signal having a second frequency and carrying the operating status data of the capacitor voltage transformer to transceiver 411.

[0049] In some implementations, after receiving the uplink microwave signal, the transceiver 411 analyzes the signal to obtain the operating status data of the capacitor voltage transformer.

[0050] The working process of the above-mentioned wireless detection system is as follows: the transceiver 411 broadcasts a downlink microwave signal with a first frequency and containing specific tag information to several above-mentioned online wireless monitoring devices located in its communication area. The online wireless monitoring devices with built-in corresponding specific tag information respond to the above-mentioned downlink microwave signal and collect energy from the downlink microwave signal and convert it into direct current. The controller 313 operates under the power supply of direct current and generates high and low level control signals containing the above-mentioned specific tag information. The modulation element 314 responds to the high and low level control signals and turns on and off the signal with the second frequency generated by the voltage-controlled oscillator 312. The antenna 316 couples the signal with the second frequency in the on state and outputs it to form an uplink microwave signal. After receiving the uplink microwave signal, the transceiver 411 analyzes it to obtain the operating status of the capacitive voltage transformer.

[0051] It can be understood that in the above process, the relationship between the frequency output by the voltage-controlled oscillator 312 and the current output by the current sensor 211 can be pre-calibrated; similarly, the relationship between the current output by the current sensor 211 and the capacitance of the capacitive voltage transformer can also be obtained by pre-calibration.

[0052] The present invention's online wireless monitoring system for capacitor voltage transformers is easy to install, requires no disconnection of the transmission line being tested, and does not affect daily operations. By monitoring the capacitance changes of the capacitor voltage transformers online in real time, it offers high accuracy and a low false alarm rate. The wireless monitoring method overcomes the challenges of difficult on-site wiring, high operational risks, and difficult post-maintenance.

[0053] The present invention further provides an embodiment of a method for online wireless monitoring of a capacitor voltage transformer, which comprises the following steps:

[0054] Step 1: The transceiver 411 broadcasts a downlink microwave signal having a first frequency and containing specific tag information into free space;

[0055] Step 2: Several online wireless monitoring devices located within the effective communication area of the transceiver 411 receive the downlink microwave signal sent by the transceiver 411;

[0056] Step 3: The online wireless monitoring device with the aforementioned specific tag information embedded therein sends an uplink microwave signal with a second frequency carrying the operating status data of the capacitor voltage transformer to the transceiver 411;

[0057] Step 4: The transceiver 411 receives the uplink microwave signal and parses it to obtain the operating status data of the capacitor voltage transformer.

[0058] In step 3, the following sub-steps may be included:

[0059] Step 3.1: After receiving the downlink microwave signal from the transceiver 411, the online wireless monitoring device with the aforementioned specific tag information rectifies the downlink microwave signal and converts it into direct current.

[0060] Step 3.2: The controller 313 operates under the power supply of DC and generates high and low level control signals containing the aforementioned specific tag information;

[0061] Step 3.3: The modulation element 314 responds to the high and low level control signals and performs on-off operations on the signal with the second frequency generated by the voltage controlled oscillator 312; wherein the signal with the second frequency generated by the voltage controlled oscillator 312 represents the operating status data of the capacitor voltage transformer;

[0062] In step 3.4, the antenna 316 couples and outputs the signal with the second frequency in the on state to form an uplink microwave signal, and sends the signal to the transceiver 411 .

[0063] In the description of the embodiments of the present invention, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "center", "top", "bottom", "top", "bottom", "inside", "outside", "inner side", "outer side" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. Among them, "inside" refers to an internal or enclosed area or space. "Periphery" refers to the area surrounding a specific component or specific area.

[0064] In the description of the embodiments of the present invention, the terms "first," "second," "third," and "fourth" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly specifying the number of the technical features indicated. Therefore, a feature specified as "first," "second," "third," or "fourth" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0065] In the description of the embodiments of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," "connected," and "assembled" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections, indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention in specific circumstances.

[0066] In the description of the embodiments of the present invention, specific features, structures, materials or characteristics may be combined in an appropriate manner in any one or more embodiments or examples.

[0067] In describing the embodiments of the present invention, it should be understood that "-" and "~" represent a range between two values, and the range includes the endpoints. For example, "AB" represents a range greater than or equal to A and less than or equal to B. "A~B" represents a range greater than or equal to A and less than or equal to B.

[0068] In describing the embodiments of the present invention, the term "and / or" is used herein to describe a relationship between associated objects, indicating that three possible relationships exist. For example, "A and / or B" can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone. Furthermore, the character " / " is generally used herein to indicate that the associated objects are in an "or" relationship.

[0069] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A capacitive voltage transformer online wireless monitoring device, characterized in that: include: Current sensors, current-to-voltage converters, voltage-controlled oscillators, controllers, energy harvesters, modulation elements, and antennas; The current sensor, current-voltage converter, voltage-controlled oscillator, modulation element and antenna are electrically connected in sequence; The antenna, energy harvester, controller and modulation element are electrically connected in sequence; The current sensor is mounted on the transmission line of the capacitor voltage transformer and is configured to detect the induced current on the transmission line; The current-voltage converter is configured to convert the current generated by the current sensor into a voltage; The voltage-controlled oscillator is configured to output a frequency corresponding to the voltage output by the current-voltage converter.

2. The online wireless monitoring device for capacitor voltage transformer according to claim 1, characterized in that: The antenna is configured to receive a downlink microwave signal having a first frequency and send an uplink microwave signal having a second frequency, wherein the first frequency is different from the second frequency.

3. The online wireless monitoring device for capacitor voltage transformer according to claim 2, characterized in that: The energy harvester is configured to convert the downlink microwave signal coupled by the antenna into direct current and store the direct current to provide power for the controller.

4. The online wireless monitoring device for capacitor voltage transformer according to claim 1, characterized in that: The controller is configured to have built-in tag information, and operates under the power provided by the energy harvester, and outputs high and low level signals representing the tag information to the modulation element.

5. The online wireless monitoring device for capacitor voltage transformer according to claim 1, characterized in that: The modulation element is configured to modulate the signal output by the voltage-controlled oscillator under the control instruction of the controller.

6. The online wireless monitoring device for capacitor voltage transformer according to claim 1, characterized in that: The modulation element is a switching element.

7. The online wireless monitoring device for capacitor voltage transformer according to claim 1, characterized in that: The current sensor adopts an open-close through-core structure.

8. A capacitive voltage transformer online wireless monitoring system, characterized in that: It comprises a transceiver and a plurality of online wireless monitoring devices for capacitor voltage transformers according to any one of claims 1 to 7; The transceiver is configured to broadcast a downlink microwave signal having a first frequency and containing specific tag information into free space, and receive an uplink microwave signal having a second frequency and carrying capacitor voltage transformer operating status data sent by a capacitor voltage transformer online wireless monitoring device with built-in specific tag information, and parse the capacitor voltage transformer operating status data.

9. A method for online wireless monitoring of a capacitor voltage transformer, applied to the online wireless monitoring system for a capacitor voltage transformer according to claim 8, characterized in that: The following steps are involved: Step 1: The transceiver broadcasts a downlink microwave signal having a first frequency and containing specific tag information into free space; Step 2: Several online wireless monitoring devices located within the effective communication area of the transceiver receive the downlink microwave signal sent by the transceiver; Step 3: The online wireless monitoring device with the built-in specific tag information sends an uplink microwave signal with a second frequency carrying the operating status data of the capacitor voltage transformer to a transceiver; Step 4: The transceiver receives the uplink microwave signal and parses it to obtain the operating status data of the capacitor voltage transformer.

10. The online wireless monitoring method for capacitor voltage transformer according to claim 9, characterized in that: Step 3 also includes the following sub-steps: Step 3.1: After receiving the downlink microwave signal from the transceiver, the online wireless monitoring device with the aforementioned specific tag information rectifies the downlink microwave signal and converts it into direct current. Step 3.2: The controller operates under the power supply of direct current and generates high and low level control signals containing the aforementioned specific tag information; Step 3.3: The modulation element responds to the high and low level control signals and performs on-off operations on the signal with the second frequency generated by the voltage controlled oscillator; wherein the signal with the second frequency generated by the voltage controlled oscillator represents the operating status data of the capacitor voltage transformer; In step 3.4, the antenna couples and outputs the signal with the second frequency in the on state to form an uplink microwave signal, and sends the signal to the transceiver.

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