CN110297124B - Non-grounded voltage measuring device and method - Google Patents
Non-grounded voltage measuring device and method Download PDFInfo
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- G01R19/25—Arrangements for measuring currents or voltages or for indicating presence or sign thereof using digital measurement techniques
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- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
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Abstract
The invention discloses a non-grounded voltage measuring device and a non-grounded voltage measuring method, wherein a corresponding relation is established between the voltage of a wire to be measured and the equivalent capacitance of the metal plate to the wire to be measured and a virtual ground in a mode of placing the metal plate between the wire to be measured and the virtual ground, and then a voltage signal representing the corresponding relation is subjected to high-frequency signal modulation and frequency division processing to calculate the voltage of the wire to be measured. It can be seen that the measurement device of the present application employs virtual voltage measurement calculation without insulation design; moreover, the measuring device of the application uses less devices, has smaller volume, is simple and convenient to assemble and disassemble and has higher construction safety, thereby meeting the development requirement of the intelligent power grid.
Description
Technical Field
The invention relates to the technical field of power measurement, in particular to a non-grounded voltage measuring device and method.
Background
The voltage signal parameters are key parameters of metering, fault detection and relay protection in the power system. At present, in an electric power system, a grounded voltage transformer (such as an electromagnetic voltage transformer or a capacitive voltage transformer) is generally used to isolate and reduce a voltage to a low voltage range that can be directly measured, and then a measurement device is used to obtain a voltage parameter. However, the conventional electromagnetic voltage transformer and the conventional capacitive voltage transformer both have the disadvantages of large volume, complex insulating structure and the like, and are gradually difficult to adapt to the development requirements of the smart grid.
Therefore, how to provide a solution to the above technical problem is a problem that needs to be solved by those skilled in the art.
Disclosure of Invention
The invention aims to provide a non-grounded voltage measuring device and a non-grounded voltage measuring method, which adopt virtual ground to measure and calculate voltage without insulation design; moreover, the measuring device of the application uses less devices, has smaller volume, is simple and convenient to assemble and disassemble and has higher construction safety, thereby meeting the development requirement of the intelligent power grid.
In order to solve the above technical problem, the present invention provides a non-grounded voltage measuring device, including:
the metal plate is placed between a wire to be tested and a virtual ground and used for converting a first voltage signal of the wire to be tested into a second voltage signal representing equivalent capacitance values of the metal plate to the wire to be tested and the virtual ground;
the signal processing circuit is used for modulating and frequency-dividing the second voltage signal and a high-frequency excitation signal to obtain a first frequency signal representing the corresponding relation between the high-frequency excitation signal and the equivalent capacitance value and a second frequency signal representing the corresponding relation between the first voltage signal and the equivalent capacitance value;
and the control module is used for obtaining the equivalent capacitance value according to the first frequency signal and the high-frequency excitation signal and obtaining the first voltage signal according to the second frequency signal and the equivalent capacitance value.
Preferably, the signal processing circuit comprises an operational amplifier, a capacitor, a subtractor and a frequency division module; wherein:
the input positive end of the operational amplifier is connected with the high-frequency excitation signal, the input negative end of the operational amplifier is respectively connected with the metal plate and the first end of the capacitor, the second end of the capacitor is respectively connected with the output end of the operational amplifier and the input negative end of the subtracter, and the input positive end of the subtracter is connected with the high-frequency excitation signal;
the frequency division module is used for carrying out frequency division processing on the modulation signal output by the subtracter to obtain a first frequency signal representing the corresponding relation between the high-frequency excitation signal and the equivalent capacitance value and a second frequency signal representing the corresponding relation between the first voltage signal and the equivalent capacitance value.
Preferably, the frequency dividing module includes:
the first filter is connected with the output end of the subtracter and is used for filtering the modulation signal output by the subtracter to obtain a first frequency signal representing the corresponding relation between the high-frequency excitation signal and the equivalent capacitance value;
and the second filter is connected with the output end of the subtracter and is used for filtering the modulation signal output by the subtracter to obtain a second frequency signal representing the corresponding relation between the first voltage signal and the equivalent capacitance value.
Preferably, the control module comprises:
the A/D converters are respectively connected with the output ends of the first filter and the second filter and are used for respectively carrying out analog-to-digital conversion on the first frequency signal and the second frequency signal to obtain a first frequency digital signal and a second frequency digital signal;
and the controller is connected with the output end of the A/D converter and is used for solving the equivalent capacitance value according to the first frequency digital signal and the digital signal of the high-frequency excitation signal and solving the signal amplitude of the first voltage signal according to the second frequency digital signal and the equivalent capacitance value.
Preferably, the frequency dividing module is integrated in the control module;
correspondingly, the control module comprises:
the A/D converter is connected with the output end of the subtracter and is used for carrying out analog-to-digital conversion on the modulation signal output by the subtracter to obtain a modulation digital signal;
the controller is connected with the output end of the A/D converter and is used for carrying out frequency division processing on the modulation digital signal by utilizing a pre-stored frequency division program to obtain a first frequency digital signal representing the corresponding relation between the high-frequency excitation signal and the equivalent capacitance value and a second frequency digital signal representing the corresponding relation between the first voltage signal and the equivalent capacitance value; and calculating the equivalent capacitance value according to the first frequency digital signal and the digital signal of the high-frequency excitation signal, and calculating the signal amplitude of the first voltage signal according to the second frequency digital signal and the equivalent capacitance value.
Preferably, the non-grounded voltage measuring device further includes:
the wireless transmission module is connected with the controller; the controller is further used for transmitting the signal amplitude of the first voltage signal to remote terminal equipment through the wireless transmission module.
Preferably, the wireless transmission module is specifically a bluetooth module.
Preferably, the non-grounded voltage measuring device further includes:
a memory connected to the controller; the controller is further configured to store a signal amplitude of the first voltage signal to the memory.
In order to solve the above technical problem, the present invention further provides a non-grounded voltage measuring method, including:
converting a first voltage signal of a wire to be tested into a second voltage signal representing equivalent capacitance values of the wire to be tested and a virtual ground by using a metal plate placed between the wire to be tested and the virtual ground;
modulating and frequency-dividing the second voltage signal and a high-frequency excitation signal to obtain a first frequency signal representing the corresponding relation between the high-frequency excitation signal and the equivalent capacitance value and a second frequency signal representing the corresponding relation between the first voltage signal and the equivalent capacitance value;
and obtaining the equivalent capacitance value according to the first frequency signal and the high-frequency excitation signal, and obtaining the first voltage signal according to the second frequency signal and the equivalent capacitance value.
The invention provides a non-grounded voltage measuring device, which establishes a corresponding relation between the voltage of a wire to be measured and the equivalent capacitance of the metal plate to the wire to be measured and a virtual ground in a mode of placing the metal plate between the wire to be measured and the virtual ground, and then calculates the voltage of the wire to be measured after a voltage signal representing the corresponding relation is modulated by a high-frequency signal and subjected to frequency division processing. It can be seen that the measurement device of the present application employs virtual voltage measurement calculation without insulation design; moreover, the measuring device of the application uses less devices, has smaller volume, is simple and convenient to assemble and disassemble and has higher construction safety, thereby meeting the development requirement of the intelligent power grid.
The invention also provides a non-grounded voltage measuring method which has the same beneficial effects as the measuring device.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed in the prior art and the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.
Fig. 1 is a schematic structural diagram of an ungrounded voltage measurement apparatus according to an embodiment of the present invention;
fig. 2 is a schematic structural diagram of an ungrounded voltage measurement apparatus according to an embodiment of the present invention;
fig. 3 is a schematic structural diagram of another non-grounded voltage measuring device according to an embodiment of the present invention;
fig. 4 is a flowchart of a non-grounded voltage measuring method according to an embodiment of the invention.
Detailed Description
The core of the invention is to provide a non-grounded voltage measuring device and a method, which adopt virtual ground to measure and calculate the voltage without insulation design; moreover, the measuring device of the application uses less devices, has smaller volume, is simple and convenient to assemble and disassemble and has higher construction safety, thereby meeting the development requirement of the intelligent power grid.
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Referring to fig. 1, fig. 1 is a schematic structural diagram of an ungrounded voltage measurement apparatus according to an embodiment of the present invention.
The non-grounded voltage measuring device includes:
the metal plate 1 is placed between the wire to be tested and the virtual ground and used for converting a first voltage signal of the wire to be tested into a second voltage signal representing equivalent capacitance values of the wire to be tested and the virtual ground of the metal plate 1;
the signal processing circuit 2 is used for modulating and frequency-dividing the second voltage signal and the high-frequency excitation signal to obtain a first frequency signal representing the corresponding relation between the high-frequency excitation signal and the equivalent capacitance value and a second frequency signal representing the corresponding relation between the first voltage signal and the equivalent capacitance value;
and the control module 3 is used for obtaining an equivalent capacitance value according to the first frequency signal and the high-frequency excitation signal, and obtaining a first voltage signal according to the second frequency signal and the equivalent capacitance value.
Specifically, the non-grounded voltage measuring device of the present application includes a metal plate 1, a signal processing circuit 2 and a control module 3, and the working principle thereof is as follows:
as shown in FIG. 1, a metal plate 1 is placed between the wire to be tested and the virtual ground (the node in the circuit that maintains the constant reference potential, which is not directly connected to the actual ground), so that the equivalent capacitance value of the metal plate 1 to the wire to be tested is C2The equivalent capacitance value of the metal plate 1 to the virtual ground is Cp. If the signal amplitude of the first voltage signal of the wire to be tested is VLWhen the potential of the wire to be tested is taken as the reference ground, the potential of the virtual ground is-VL. It can be seen that the second voltage signal on the metal plate 1 is associated with the voltage to be measuredThe first voltage signal of the wire to be tested and the equivalent capacitance value of the metal plate 1 to the wire to be tested and the virtual ground have a certain variable relation.
A second voltage signal of the metal plate 1 is input into the signal processing circuit 2, the signal processing circuit 2 firstly modulates the second voltage signal with a high-frequency excitation signal (the frequency of the first voltage signal is in the Hz magnitude, the frequency of the high-frequency excitation signal is in the MHz magnitude, the amplitude of the first voltage signal is in the kV magnitude, and the amplitude of the high-frequency excitation signal is in the V magnitude) to obtain a modulation signal; and then, carrying out frequency division processing on the modulation signal (the high-frequency signal and the low-frequency signal are output in two paths, one path outputs the high-frequency signal, and the other path outputs the low-frequency signal) so as to obtain a first frequency signal representing the corresponding relation between the high-frequency excitation signal and the equivalent capacitance value and a second frequency signal representing the corresponding relation between the first voltage signal and the equivalent capacitance value.
The signal processing circuit 2 inputs the first frequency signal and the second frequency signal (known quantity) into the control module 3, the control module 3 can obtain an equivalent capacitance value according to the first frequency signal (representing the corresponding relation between the high-frequency excitation signal and the equivalent capacitance value) and the high-frequency excitation signal (known quantity), then can obtain a first voltage signal according to the second frequency signal (representing the corresponding relation between the first voltage signal and the equivalent capacitance value) and the equivalent capacitance value (known quantity), and obtain a voltage amplitude V of the wire to be measuredL。
The invention provides a non-grounded voltage measuring device, which establishes a corresponding relation between the voltage of a wire to be measured and the equivalent capacitance of the metal plate to the wire to be measured and a virtual ground in a mode of placing the metal plate between the wire to be measured and the virtual ground, and then calculates the voltage of the wire to be measured after a voltage signal representing the corresponding relation is modulated by a high-frequency signal and subjected to frequency division processing. It can be seen that the measurement device of the present application employs virtual voltage measurement calculation without insulation design; moreover, the measuring device of the application uses less devices, has smaller volume, is simple and convenient to assemble and disassemble and has higher construction safety, thereby meeting the development requirement of the intelligent power grid.
On the basis of the above-described embodiment:
referring to fig. 2, fig. 2 is a schematic structural diagram of an ungrounded voltage measurement apparatus according to an embodiment of the present invention.
As an alternative embodiment, the signal processing circuit 2 includes an operational amplifier 21, a capacitor 22, a subtractor 23, and a frequency dividing module 24; wherein:
the input positive end of the operational amplifier 21 is connected with a high-frequency excitation signal, the input negative end of the operational amplifier 21 is respectively connected with the metal plate 1 and the first end of the capacitor 22, the second end of the capacitor 22 is respectively connected with the output end of the operational amplifier 21 and the input negative end of the subtracter 23, and the input positive end of the subtracter 23 is connected with the high-frequency excitation signal;
the frequency dividing module 24 is configured to perform frequency dividing processing on the modulation signal output by the subtractor 23 to obtain a first frequency signal representing a correspondence between the high-frequency excitation signal and the equivalent capacitance value, and a second frequency signal representing a correspondence between the first voltage signal and the equivalent capacitance value.
Specifically, the signal processing circuit 2 of the present application includes an operational amplifier 21, a capacitor 22, a subtractor 23, and a frequency dividing module 24, and the operating principle thereof is as follows:
applying a high frequency excitation signal V to the non-inverting terminal of the operational amplifier 21HThe voltage V at the point M is calculated in the Laplace domain by using the proportional amplification principle of the operational amplifier 21MComprises the following steps:
Due to the high frequency excitation signal VHIs a known quantity, so that the subtracter 23 is adopted in the circuit to simplify the operation, and the voltage V at the N pointNComprises the following steps:
taking into account the amplitude of the first voltage signalIn the kV magnitude, the amplitude of the high-frequency excitation signal is in the V magnitude, and then V isL'＞＞VHAnd the equivalent capacitance C of the metal plate 1 to the lead wire to be tested2In the pF range, Cs＞＞C2Therefore, it is
Very small, negligible, the N point voltage is reduced to:
it can be seen that the signal output by the subtractor 23 is the high frequency signal mentioned in the above embodiments
+ low frequency signal
The modulated signal of (2).
The modulated signal output by the subtractor 23 is input to a frequency division module 24, and the frequency division module 24 performs frequency division processing on the modulated signal to obtain a first frequency signal representing the corresponding relationship between the high-frequency excitation signal and the equivalent capacitance value
And a second frequency signal representing a correspondence between the first voltage signal and the equivalent capacitance value
As an alternative embodiment, the frequency dividing module 24 includes:
the first filter is connected with the output end of the subtracter 23 and is used for filtering the modulation signal output by the subtracter 23 to obtain a first frequency signal representing the corresponding relation between the high-frequency excitation signal and the equivalent capacitance value;
and the second filter is connected with the output end of the subtracter 23 and is used for filtering the modulation signal output by the subtracter 23 to obtain a second frequency signal representing the corresponding relation between the first voltage signal and the equivalent capacitance value.
Specifically, the frequency dividing module 24 of the present application may be implemented by a hardware structure, and specifically, the signal frequency division is implemented by using a filtering principle of a filter (to effectively filter frequencies other than a frequency point of a specific frequency, so as to obtain a signal of the specific frequency).
More specifically, the present application determines in advance the frequency ranges of a first frequency signal (high frequency signal) and a second frequency signal (low frequency signal) in a modulated signal, and then separates the first frequency signal using a first filter that filters out the low frequency signal and retains the high frequency signal, and separates the second frequency signal using a second filter that filters out the high frequency signal and retains the low frequency signal.
As an alternative embodiment, the control module 3 comprises:
the a/D converter 31 is connected to the output ends of the first filter and the second filter, and is configured to perform analog-to-digital conversion on the first frequency signal and the second frequency signal, respectively, to obtain a first frequency digital signal and a second frequency digital signal;
and the controller 32 is connected with the output end of the a/D converter 31 and is used for calculating an equivalent capacitance value according to the first frequency digital signal and the digital signal of the high-frequency excitation signal, and calculating the signal amplitude value of the first voltage signal according to the second frequency digital signal and the equivalent capacitance value.
Specifically, the control module 3 of the present application includes an a/D (analog/digital) converter 31 and a controller 32, and its operating principle is:
the first filter inputs the first frequency signal to the a/D converter 31, the a/D converter 31 performs analog-to-digital conversion on the first frequency signal to obtain a first frequency digital signal, and then the first frequency digital signal is input to the controller 32. Similarly, the second filter inputs the second frequency signal to the a/D converter 31, the a/D converter 31 performs analog-to-digital conversion on the second frequency signal to obtain a second frequency digital signal, and then the second frequency digital signal is input to the controller 32.
The controller 32 is responsive to the first frequency digital signal (characterizing the high frequency excitation signal)Corresponding relation with the equivalent capacitance value) and the digital signal (known quantity) of the high-frequency excitation signal to obtain the equivalent capacitance value, and then the signal amplitude V of the first voltage signal can be obtained according to the second frequency digital signal (representing the corresponding relation between the first voltage signal and the equivalent capacitance value) and the equivalent capacitance value (known quantity)L。
Referring to fig. 3, fig. 3 is a schematic structural diagram of another non-grounded voltage measuring device according to an embodiment of the present invention.
As an alternative embodiment, the frequency dividing module 24 is integrated in the control module 3;
accordingly, the control module 3 comprises:
the a/D converter 31 is connected to the output end of the subtractor 23, and is configured to perform analog-to-digital conversion on the modulation signal output by the subtractor 23 to obtain a modulation digital signal;
the controller 32 is connected to the output end of the a/D converter 31, and is configured to perform frequency division processing on the modulated digital signal by using a pre-stored frequency division program to obtain a first frequency digital signal representing a correspondence relationship between the high-frequency excitation signal and the equivalent capacitance value, and a second frequency digital signal representing a correspondence relationship between the first voltage signal and the equivalent capacitance value; and calculating an equivalent capacitance value according to the first frequency digital signal and the digital signal of the high-frequency excitation signal, and calculating the signal amplitude of the first voltage signal according to the second frequency digital signal and the equivalent capacitance value.
Specifically, the frequency dividing module 24 of the present application may be implemented by a software program, in addition to the hardware structure mentioned in the above embodiments, specifically, the frequency dividing module 24 is integrated in the control module 3, that is, the control module 3 has a signal frequency dividing function.
More specifically, the modulation signal output by the subtractor 23 is directly input to the a/D converter 31 in the control module 3, and the a/D converter 31 performs analog-to-digital conversion on the modulation signal to obtain a modulation digital signal (a first frequency digital signal + a second frequency digital signal), and then inputs the modulation digital signal to the controller 32. The controller 32 first performs frequency division processing on the modulated digital signal by using a pre-stored frequency division program to obtain a first frequency digital signal and a second frequency digital signalWord signal, obtaining equivalent capacitance value according to the first frequency digital signal and the digital signal of the high-frequency excitation signal, and obtaining signal amplitude V of the first voltage signal according to the second frequency digital signal and the equivalent capacitance valueL。
Further, the controller 32 of the present application can be selected from but not limited to an MCU (Micro Control Unit), and the present application is not limited thereto. Further, the high frequency excitation signal of the present application may be generated by the controller 32.
As an optional embodiment, the non-grounded voltage measuring apparatus further comprises:
a wireless transmission module connected to the controller 32; the controller 32 is further configured to transmit the signal amplitude of the first voltage signal to a remote terminal device via the wireless transmission module.
Further, the measuring apparatus of the present application may further include a wireless transmission module, and with the aid of the wireless transmission module, the controller 32 may wirelessly transmit the signal amplitude of the first voltage signal to the remote terminal device, so that the user can view the signal amplitude of the first voltage signal from the remote terminal device.
As an optional embodiment, the wireless transmission module is specifically a bluetooth module.
Specifically, the wireless transmission module of the present application can be selected from, but not limited to, a bluetooth module (e.g., a WiFi module), and the present application is not particularly limited thereto, depending on the actual situation.
As an optional embodiment, the non-grounded voltage measuring apparatus further comprises:
a memory connected to the controller 32; the controller 32 is further configured to store the signal amplitude of the first voltage signal to a memory.
Further, the measuring device of the present application may further include a memory for storing the signal amplitude of the first voltage signal, so as to be read and viewed by a user at a later time.
In addition, the measuring device of the present application may be powered by an external power source, or may be provided with a power supply module therein to supply power to the signal processing circuit 2, the a/D converter 31, and the controller 32.
Referring to fig. 4, fig. 4 is a flowchart of a non-grounded voltage measuring method according to an embodiment of the invention.
The non-grounded voltage measuring method comprises the following steps:
step S1: converting a first voltage signal of the wire to be tested into a second voltage signal representing equivalent capacitance values of the wire to be tested and a virtual ground by using a metal plate placed between the wire to be tested and the virtual ground;
step S2: modulating and frequency-dividing the second voltage signal and the high-frequency excitation signal to obtain a first frequency signal representing the corresponding relation between the high-frequency excitation signal and the equivalent capacitance value and a second frequency signal representing the corresponding relation between the first voltage signal and the equivalent capacitance value;
step S3: and obtaining an equivalent capacitance value according to the first frequency signal and the high-frequency excitation signal, and obtaining a first voltage signal according to the second frequency signal and the equivalent capacitance value.
For the introduction of the measurement method provided in the present application, reference is made to the embodiments of the measurement apparatus described above, and details are not repeated herein.
It is further noted that, in the present specification, relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (6)
1. An ungrounded voltage measurement device, comprising:
the metal plate is placed between a wire to be tested and a virtual ground and used for converting a first voltage signal of the wire to be tested into a second voltage signal representing equivalent capacitance values of the metal plate to the wire to be tested and the virtual ground;
the signal processing circuit is used for modulating and frequency-dividing the second voltage signal and a high-frequency excitation signal to obtain a first frequency signal representing the corresponding relation between the high-frequency excitation signal and the equivalent capacitance value and a second frequency signal representing the corresponding relation between the first voltage signal and the equivalent capacitance value;
the control module is used for obtaining the equivalent capacitance value according to the first frequency signal and the high-frequency excitation signal and obtaining the first voltage signal according to the second frequency signal and the equivalent capacitance value;
the signal processing circuit comprises an operational amplifier, a capacitor, a subtracter and a frequency division module; wherein:
the input positive end of the operational amplifier is connected with the high-frequency excitation signal, the input negative end of the operational amplifier is respectively connected with the metal plate and the first end of the capacitor, the second end of the capacitor is respectively connected with the output end of the operational amplifier and the input negative end of the subtracter, and the input positive end of the subtracter is connected with the high-frequency excitation signal;
the frequency division module is used for carrying out frequency division processing on the modulation signal output by the subtracter to obtain a first frequency signal representing the corresponding relation between the high-frequency excitation signal and the equivalent capacitance value and a second frequency signal representing the corresponding relation between the first voltage signal and the equivalent capacitance value;
the frequency division module comprises:
the first filter is connected with the output end of the subtracter and is used for filtering the modulation signal output by the subtracter to obtain a first frequency signal representing the corresponding relation between the high-frequency excitation signal and the equivalent capacitance value;
the second filter is connected with the output end of the subtracter and is used for filtering the modulation signal output by the subtracter to obtain a second frequency signal representing the corresponding relation between the first voltage signal and the equivalent capacitance value;
the control module includes:
the A/D converters are respectively connected with the output ends of the first filter and the second filter and are used for respectively carrying out analog-to-digital conversion on the first frequency signal and the second frequency signal to obtain a first frequency digital signal and a second frequency digital signal;
and the controller is connected with the output end of the A/D converter and is used for solving the equivalent capacitance value according to the first frequency digital signal and the digital signal of the high-frequency excitation signal and solving the signal amplitude of the first voltage signal according to the second frequency digital signal and the equivalent capacitance value.
2. The ungrounded voltage measurement device of claim 1, wherein the frequency divider module is integrated into the control module;
correspondingly, the control module comprises:
the A/D converter is connected with the output end of the subtracter and is used for carrying out analog-to-digital conversion on the modulation signal output by the subtracter to obtain a modulation digital signal;
the controller is connected with the output end of the A/D converter and is used for carrying out frequency division processing on the modulation digital signal by utilizing a pre-stored frequency division program to obtain a first frequency digital signal representing the corresponding relation between the high-frequency excitation signal and the equivalent capacitance value and a second frequency digital signal representing the corresponding relation between the first voltage signal and the equivalent capacitance value; and calculating the equivalent capacitance value according to the first frequency digital signal and the digital signal of the high-frequency excitation signal, and calculating the signal amplitude of the first voltage signal according to the second frequency digital signal and the equivalent capacitance value.
3. The ungrounded voltage measurement device of any one of claims 1-2, further comprising:
the wireless transmission module is connected with the controller; the controller is further used for transmitting the signal amplitude of the first voltage signal to remote terminal equipment through the wireless transmission module.
4. The ungrounded voltage measurement device of claim 3, wherein the wireless transmission module is in particular a Bluetooth module.
5. The ungrounded voltage measurement device of claim 3, further comprising:
a memory connected to the controller; the controller is further configured to store a signal amplitude of the first voltage signal to the memory.
6. An ungrounded voltage measurement method using the ungrounded voltage measurement device according to any one of claims 1 to 5, comprising:
converting a first voltage signal of a wire to be tested into a second voltage signal representing equivalent capacitance values of the wire to be tested and a virtual ground by using a metal plate placed between the wire to be tested and the virtual ground;
modulating and frequency-dividing the second voltage signal and a high-frequency excitation signal to obtain a first frequency signal representing the corresponding relation between the high-frequency excitation signal and the equivalent capacitance value and a second frequency signal representing the corresponding relation between the first voltage signal and the equivalent capacitance value;
and obtaining the equivalent capacitance value according to the first frequency signal and the high-frequency excitation signal, and obtaining the first voltage signal according to the second frequency signal and the equivalent capacitance value.
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| CN201910721658.4A Active CN110297124B (en) | 2019-08-06 | 2019-08-06 | Non-grounded voltage measuring device and method |
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| CN101281220A (en) * | 2008-01-02 | 2008-10-08 | 清华大学 | Capacitance testing circuit and capacitance-type sensor interface circuit chip thereof |
| CN204330892U (en) * | 2015-01-07 | 2015-05-13 | 四川锦江电子科技有限公司 | A kind of high-frequency treatment device on resistance testing circuit |
| CN105353223A (en) * | 2015-12-02 | 2016-02-24 | 浙江大学 | Capacitor coupling noncontact conductance measurement device and method |
| CN106353549A (en) * | 2016-08-15 | 2017-01-25 | 广州致远电子股份有限公司 | Adjustable circuit device and voltage measuring device |
| CN108548982A (en) * | 2018-03-14 | 2018-09-18 | 云南电网有限责任公司电力科学研究院 | A kind of test method of capacitance current, apparatus and system |
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| US3622881A (en) * | 1969-03-21 | 1971-11-23 | Ford Motor Co | Voltage measuring apparatus employing a josephson junction |
| US5450007A (en) * | 1991-09-19 | 1995-09-12 | Ampy Automation-Digilog Limited | Method and apparatus for power measuring |
| GB2285692A (en) * | 1993-03-13 | 1995-07-19 | Ampy Automation Digilog | Power meters |
| CN2600819Y (en) * | 2002-09-22 | 2004-01-21 | 西安高压电器研究所 | Device for measuring voltage and current of high-tension switch equipment |
| CN101281220A (en) * | 2008-01-02 | 2008-10-08 | 清华大学 | Capacitance testing circuit and capacitance-type sensor interface circuit chip thereof |
| CN204330892U (en) * | 2015-01-07 | 2015-05-13 | 四川锦江电子科技有限公司 | A kind of high-frequency treatment device on resistance testing circuit |
| CN105353223A (en) * | 2015-12-02 | 2016-02-24 | 浙江大学 | Capacitor coupling noncontact conductance measurement device and method |
| CN106353549A (en) * | 2016-08-15 | 2017-01-25 | 广州致远电子股份有限公司 | Adjustable circuit device and voltage measuring device |
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