CN112345994A - CVT harmonic measurement error self-calibration system based on cloud platform and calibration method thereof - Google Patents
CVT harmonic measurement error self-calibration system based on cloud platform and calibration method thereof Download PDFInfo
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Abstract
The invention relates to the technical field of measurement of a capacitor voltage transformer, in particular to a CVT harmonic measurement error self-calibration system based on a cloud platform and a calibration method thereof. Compared with the conventional mode of determining the harmonic transmission characteristic parameters of the CVT through a simulation experiment and calibrating the harmonic data, the method ensures the authenticity of the calibration data, improves the accuracy of harmonic measurement error calibration, can calibrate a plurality of groups of harmonic data simultaneously, and increases the calibration processing efficiency. On the other hand, compared with the mode that a CVT harmonic measurement error calibration device is additionally arranged on site and each capacitor voltage transformer is calibrated separately, the invention reduces the workload and the economic cost.
Description
Technical Field
The invention relates to the technical field of measurement of a capacitor voltage transformer, in particular to a CVT harmonic measurement error self-calibration system based on a cloud platform and a calibration method thereof.
Background
In an electric power system, a CVT (capacitor voltage transformer) can be used for voltage measurement, high-frequency communication and relay protection of a neutral point direct grounding system with the level of 110kV or above, and is widely applied to buses of a booster station and a step-down transformer substation of a power plant. However, the method is explicitly proposed in the electric energy quality public power grid harmonic GB/T14549 + 1993: the "capacitive voltage transformer cannot be used for harmonic measurement. In harmonic voltage measurement, when there is a high need for the harmonic order or measurement accuracy, a resistive voltage divider or a capacitive voltage divider "should be used. Therefore, how to ensure the accuracy of the harmonic voltage data on the premise of using the CVT for voltage measurement becomes one of the important problems that must be solved in the power grid harmonic analysis work.
In general, there are two ways to achieve CVT harmonic measurement error calibration: 1) determining harmonic transfer characteristic parameters of the CVT by a simulation experiment method, and further calibrating harmonic data measured on the monitoring site; 2) the method for calibrating the CVT harmonic measurement error is realized by additionally arranging the CVT harmonic measurement error calibrating device on the monitoring site, and then the calibrated harmonic data is obtained by the harmonic monitoring device. The above method mainly has the following disadvantages: 1) because the experimental environment is different from the field environment, multiple technical indexes of the CVT in the experimental environment are not in accordance with the actual condition, the accuracy of transmission characteristic parameter results is inevitably reduced, and the harmonic measurement error calibration effect is poor and the efficiency is low; 2) the CVT in the power grid is large in quantity and wide in distribution, the method of additionally arranging the CVT harmonic measurement error calibration device is adopted, the workload and the working cost are inevitably greatly increased, and the practicability is low.
Disclosure of Invention
The invention provides a CVT harmonic measurement error self-calibration system based on a cloud platform and a calibration method thereof, overcomes the defects of the prior art, and can effectively solve the problems that the existing mode of determining harmonic transmission characteristic parameters of the CVT through simulation experiments and calibrating harmonic data has low data authenticity and is easy to cause poor harmonic measurement error calibration effect.
One of the technical schemes of the invention is realized by the following measures: a CVT harmonic measurement error self-calibration system based on a cloud platform comprises a cloud server, a plurality of harmonic data acquisition units and a plurality of communication units, wherein the harmonic data acquisition units and the communication units are arranged at the front end, and are the same in number and in one-to-one correspondence;
the harmonic data acquisition unit is used for measuring and acquiring harmonic data corresponding to the capacitor voltage transformer;
the communication unit is used for establishing a communication link between the cloud server and the corresponding harmonic data acquisition unit and uploading the harmonic data to the cloud server;
and the cloud server is used for acquiring the CVT equivalent circuit parameters and calibrating the corresponding harmonic data based on the CVT equivalent circuit parameters.
The following is further optimization or/and improvement of the technical scheme of the invention:
the cloud server comprises a CVT equivalent circuit parameter storage module, a harmonic data storage module and a harmonic data calibration module;
the CVT equivalent circuit parameter storage module is used for storing CVT equivalent circuit parameters;
the harmonic data storage module is used for receiving and storing the harmonic data uploaded by the harmonic data acquisition unit and storing the calibrated harmonic data;
and the harmonic data calibration module is used for calibrating corresponding harmonic data based on the CVT equivalent circuit parameters.
The harmonic data calibration module comprises a harmonic distortion data acquisition module and a calibration module;
the harmonic distortion data acquisition module is used for acquiring CVT harmonic distortion data through a transfer function based on CVT equivalent circuit parameters;
a calibration module to calibrate the harmonic data using the CVT harmonic distortion data.
The harmonic data acquisition unit comprises a data interface module, an A/D sampling plate, a control module, a storage module, a communication interface and a power module, wherein the data interface module is connected with the A/D sampling plate, the A/D sampling plate is connected with the control module, and the control module is respectively connected with the storage module, the communication interface and the power module.
The control module comprises a DSP controller and an ARM processor, the DSP controller is connected with the ARM processor, and the ARM processor is respectively connected with the storage module, the communication interface and the power module.
The system further comprises a client, wherein the client is used for inputting the CVT equivalent circuit parameters and performing visualization processing on the harmonic data before calibration and the harmonic data after calibration, and the visualization processing comprises displaying, viewing, exporting and managing.
The second technical scheme of the invention is realized by the following measures: a calibration method of a CVT harmonic measurement error self-calibration system based on a cloud platform comprises the following steps:
the cloud server acquires and stores CVT equivalent circuit parameters and harmonic data uploaded by each harmonic data acquisition unit;
the cloud server obtains CVT harmonic distortion data through a transfer function based on the CVT equivalent circuit parameters;
the cloud server uses the CVT harmonic distortion data to calibrate and store the harmonic data.
The following is further optimization or/and improvement of the technical scheme of the invention:
the method further comprises the step of carrying out visualization processing on the calibrated harmonic data through the client after the harmonic data is calibrated and stored by using the CVT harmonic distortion data, wherein the visualization processing comprises displaying, viewing, exporting and managing.
The invention provides a CVT harmonic measurement error self-calibration system based on a cloud platform, which can automatically measure and acquire harmonic data of a plurality of Capacitor Voltage Transformers (CVTs) through a plurality of harmonic data acquisition units in a one-to-one corresponding manner, and upload the harmonic data to a cloud server, wherein the cloud server calibrates the corresponding harmonic data based on front-end field CVT equivalent circuit parameters, and the CVT equivalent circuit parameters can be modified according to actual conditions. Therefore, compared with the conventional mode of determining the harmonic transmission characteristic parameters of the CVT through a simulation experiment and calibrating the harmonic data, the method ensures the authenticity of the calibration data, improves the accuracy of harmonic measurement error calibration, can calibrate a plurality of groups of harmonic data simultaneously, and increases the calibration processing efficiency. On the other hand, compared with a mode that a CVT harmonic measurement error calibration device is additionally arranged on site and each Capacitor Voltage Transformer (CVT) is separately calibrated, the method has the advantages that the workload is reduced, and the economic cost is reduced.
Drawings
Fig. 1 is a circuit configuration block diagram of embodiment 1 of the present invention.
Fig. 2 is a block diagram of a cloud server according to embodiment 1 of the present invention.
Fig. 3 is a circuit block diagram of a harmonic data acquisition unit in embodiment 1 of the present invention.
Fig. 4 is a circuit configuration diagram of an equivalent circuit of a CVT in embodiment 1 of the present invention.
FIG. 5 is a flow chart of example 2 of the present invention.
Detailed Description
The present invention is not limited by the following examples, and specific embodiments may be determined according to the technical solutions and practical situations of the present invention.
The invention is further described with reference to the following examples and figures:
example 1: as shown in fig. 1, the cloud platform-based CVT harmonic measurement error self-calibration system comprises a cloud server, a plurality of harmonic data acquisition units and a plurality of communication units, wherein the harmonic data acquisition units and the communication units are arranged at the front end, and are the same in number and in one-to-one correspondence;
the harmonic data acquisition unit is used for measuring and acquiring harmonic data corresponding to the capacitor voltage transformer;
the communication unit is used for establishing a communication link between the cloud server and the corresponding harmonic data acquisition unit and uploading the harmonic data to the cloud server;
and the cloud server is used for acquiring the CVT equivalent circuit parameters and calibrating the corresponding harmonic data based on the CVT equivalent circuit parameters.
In the technical scheme, the harmonic data acquisition unit is connected with the Capacitor Voltage Transformer (CVT) and is used for measuring and acquiring harmonic data of the Capacitor Voltage Transformer (CVT), wherein the harmonic data acquisition unit can measure and acquire the harmonic data of the CVT for 2 times to 50 times, and the harmonic data comprises harmonic voltage, harmonic current and a harmonic phase angle. The communication unit is a conventional communication module, and can be a wireless communication module, and transmits the harmonic data measured and acquired by the corresponding harmonic data acquisition unit to the cloud server.
In the technical scheme, the cloud Server can carry a Windows Server system environment, and corresponding harmonic data are calibrated based on CVT equivalent circuit parameters.
The invention provides a CVT harmonic measurement error self-calibration system based on a cloud platform, which can automatically measure and acquire harmonic data of a plurality of Capacitor Voltage Transformers (CVTs) through a plurality of harmonic data acquisition units in a one-to-one corresponding manner, and upload the harmonic data to a cloud server, wherein the cloud server calibrates the corresponding harmonic data based on front-end field CVT equivalent circuit parameters, and the CVT equivalent circuit parameters can be modified according to actual conditions. Therefore, compared with the conventional mode of determining the harmonic transmission characteristic parameters of the CVT through a simulation experiment and calibrating the harmonic data, the method ensures the authenticity of the calibration data, improves the accuracy of harmonic measurement error calibration, can calibrate a plurality of groups of harmonic data simultaneously, and increases the calibration processing efficiency. On the other hand, compared with a mode that a CVT harmonic measurement error calibration device is additionally arranged on site and each Capacitor Voltage Transformer (CVT) is separately calibrated, the method has the advantages that the workload is reduced, and the economic cost is reduced.
The following is further optimization or/and improvement of the technical scheme of the invention:
as shown in fig. 2, the cloud server includes a CVT equivalent circuit parameter storage module, a harmonic data storage module, and a harmonic data calibration module;
the CVT equivalent circuit parameter storage module is used for storing CVT equivalent circuit parameters;
the harmonic data storage module is used for receiving and storing the harmonic data uploaded by the harmonic data acquisition unit and storing the calibrated harmonic data;
and the harmonic data calibration module is used for calibrating corresponding harmonic data based on the CVT equivalent circuit parameters.
In the above technical solution, parameters of the CVT equivalent circuit can be modified according to actual conditions. The CVT equivalent circuit parameter storage module and the harmonic data storage module can be SQL Server databases.
As shown in fig. 2, the harmonic data calibration module includes a harmonic distortion data acquisition module and a calibration module;
the harmonic distortion data acquisition module is used for acquiring CVT harmonic distortion data through a transfer function based on CVT equivalent circuit parameters;
a calibration module to calibrate the harmonic data using the CVT harmonic distortion data.
The CVT equivalent circuit parameters are obtained through a CVT equivalent circuit diagram, and CVT harmonic distortion data are obtained through a transfer function based on the CVT equivalent circuit parameters.
For example, the CVT equivalent circuit diagram, C, as shown in FIG. 41、C2For high and medium voltage capacitors, L for compensating reactance, ZmIs an intermediate transformer excitation impedance,ZDis the damper equivalent impedance, ZLIs the load impedance, Zm、ZD、ZLAre all reduced to the primary side impedance of the transformer, R1Is an intermediate transformer resistance, R2To compensate for reactor resistance, CSIs an equivalent stray capacitance at the primary side of the intermediate transformer, CS1For compensating equivalent stray capacitance of reactor, U1(s) is the primary side voltage, U2(s)、U3(s) is the intermediate node voltage, U4(s) is the output voltage (reduced to the primary side of the transformer), Zd1(s) to Zd6And(s) is the equivalent impedance corresponding to each stage of port. Obtaining CVT harmonic distortion data from the CVT equivalent circuit diagram, the process of calibrating the harmonic distortion data using the CVT harmonic distortion data comprising:
(1) calculating equivalent impedance of each level port in a CVT equivalent circuit diagram, namely CVT equivalent circuit parameters;
Zd6(s)＝Zm(s)//ZD(s)//ZL(s)
Zd5(s)＝Zd6(s)+R1
Zd4(s)＝Zd5(s)//(1/sCS)
Zd3(s)＝Zd4(s)+[(R2+sL)//(1/sCS1)]
Zd2(s)＝Zd3(s)//(1/sC2)
Zd1(s)＝Zd2(s)+(1/sC1)
(2) based on the voltage division relation of the voltage on the series impedance, the transfer functions of the voltages of all stages are listed, and CVT harmonic distortion data G are obtained(s)；
Up＝U1(s)
Us＝U4(s)/N
Wherein, UpIs the primary side voltage of the CVT; u shapesIs the secondary side voltage of the CVT; n is the transformation ratio of the intermediate transformer; s is j ω, ω is angular frequency; g(s)Namely CVT harmonic distortion data represented by the transfer function.
(3) The harmonic data (harmonic voltage amplitude, phase angle) is calibrated with the CVT harmonic distortion data.
As shown in fig. 3, the harmonic data acquisition unit includes a data interface module, an a/D sampling board, a control module, a storage module, a communication interface, and a power module, where the data interface module is connected to the a/D sampling board, the a/D sampling board is connected to the control module, and the control module is connected to the storage module, the communication interface, and the power module, respectively.
In the above technical solution, the data interface module is used for being connected with a Capacitor Voltage Transformer (CVT). The communication interface is used for connecting with a communication unit. The storage module may be a memory for storing harmonic data of a Capacitance Voltage Transformer (CVT) acquired by measurement. The power supply module is used for supplying power to the control module, and the voltage of the power supply module can be 3.3V.
As shown in fig. 3, the control module includes a DSP controller and an ARM processor, the DSP controller is connected to the ARM processor, and the ARM processor is connected to the storage module, the communication interface, and the power module, respectively.
The DSP controller and the ARM processor are both in the prior known technology, and the ARM processor is communicated with the DSP controller through a full-duplex serial port. The DSP controller is used for extracting needed information from the digital signals sent by the A/D sampling plate. The ARM processor is used for sending the information extracted by the DSP controller to the communication unit so as to upload the information to the cloud server.
As shown in fig. 1, the system further includes a client, configured to enter CVT equivalent circuit parameters, and perform visualization processing on the harmonic data before calibration and the harmonic data after calibration, where the visualization processing includes displaying, viewing, exporting, and managing.
In the above technical solution, the client may be a computer that remotely accesses the cloud server through a wireless communication manner.
Example 2: as shown in fig. 5, the calibration method of the cloud platform-based CVT harmonic measurement error self-calibration system includes:
s1, the cloud server acquires and stores CVT equivalent circuit parameters and harmonic data uploaded by each harmonic data acquisition unit;
s2, the cloud server obtains CVT harmonic distortion data through a transfer function based on the CVT equivalent circuit parameters;
and S3, the cloud server uses the CVT harmonic distortion data to calibrate and store the harmonic data.
According to the technical scheme, the parameters of the CVT equivalent circuit are manually input, and can be correspondingly changed according to an actual Capacitor Voltage Transformer (CVT), so that the accuracy of harmonic measurement error calibration is improved.
The following is further optimization or/and improvement of the technical scheme of the invention:
as shown in fig. 5, after the harmonic data is calibrated and stored by using the CVT harmonic distortion data, the calibrated harmonic data is visualized by the client, and the visualization includes displaying, viewing, exporting and managing.
In the technical scheme, a worker can input CVT equivalent circuit parameters into the cloud server through the client. The above technical features constitute the best embodiment of the present invention, which has strong adaptability and best implementation effect, and unnecessary technical features can be increased or decreased according to actual needs to meet the requirements of different situations.
Claims (9)
1. A CVT harmonic measurement error self-calibration system based on a cloud platform is characterized by comprising a cloud server, a plurality of harmonic data acquisition units and a plurality of communication units, wherein the harmonic data acquisition units and the communication units are arranged at the front end, and are the same in number and in one-to-one correspondence;
the harmonic data acquisition unit is used for measuring and acquiring harmonic data corresponding to the capacitor voltage transformer;
the communication unit is used for establishing a communication link between the cloud server and the corresponding harmonic data acquisition unit and uploading the harmonic data to the cloud server;
and the cloud server is used for acquiring the CVT equivalent circuit parameters and calibrating the corresponding harmonic data based on the CVT equivalent circuit parameters.
2. The cloud platform based CVT harmonic measurement error self-calibration system of claim 1, wherein the cloud server comprises a CVT equivalent circuit parameter storage module, a harmonic data calibration module;
the CVT equivalent circuit parameter storage module is used for storing CVT equivalent circuit parameters;
the harmonic data storage module is used for receiving and storing the harmonic data uploaded by the harmonic data acquisition unit and storing the calibrated harmonic data;
and the harmonic data calibration module is used for calibrating corresponding harmonic data based on the CVT equivalent circuit parameters.
3. The cloud platform based CVT harmonic measurement error self-calibration system of claim 2 wherein the harmonic data calibration module includes a harmonic distortion data acquisition module and a calibration module;
the harmonic distortion data acquisition module is used for acquiring CVT harmonic distortion data through a transfer function based on CVT equivalent circuit parameters;
a calibration module to calibrate the harmonic data using the CVT harmonic distortion data.
4. The cloud platform based CVT harmonic measurement error self-calibration system according to claim 1, 2 or 3, characterized in that the harmonic data acquisition unit includes a data interface module, an A/D sampling board, a control module, a storage module, a communication interface, and a power module, the data interface module is connected with the A/D sampling board, the A/D sampling board is connected with the control module, and the control module is respectively connected with the storage module, the communication interface, and the power module.
5. The cloud platform based CVT harmonic measurement error self-calibration system of claim 4 wherein the control module includes a DSP controller and an ARM processor, the DSP controller is connected with the ARM processor, and the ARM processor is connected with the storage module, the communication interface, and the power module respectively.
6. The cloud platform based CVT harmonic measurement error self-calibration system according to claim 1, 2, 3 or 5, further comprising a client for entering CVT equivalent circuit parameters and performing visualization processing on the harmonic data before calibration and the harmonic data after calibration, wherein the visualization processing includes displaying, viewing, deriving and managing.
7. The cloud platform based CVT harmonic measurement error self-calibration system of claim 4 further comprising a client for entering CVT equivalent circuit parameters and performing visualization processing on the harmonic data before calibration and the harmonic data after calibration, wherein the visualization processing includes displaying, viewing, deriving and managing.
8. A calibration method of a CVT harmonic measurement error self-calibration system based on a cloud platform is characterized by comprising the following steps:
the cloud server acquires and stores CVT equivalent circuit parameters and harmonic data uploaded by each harmonic data acquisition unit;
the cloud server obtains CVT harmonic distortion data through a transfer function based on the CVT equivalent circuit parameters;
the cloud server uses the CVT harmonic distortion data to calibrate and store the harmonic data.
9. The calibration method of the cloud platform based CVT harmonic measurement error self-calibration system according to claim 8, further comprising performing visualization processing on the calibrated harmonic data through a client after the harmonic data is calibrated and stored by using CVT harmonic distortion data, wherein the visualization processing includes displaying, viewing, deriving and managing.
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| CN111812573A (en) * | 2020-06-09 | 2020-10-23 | 国网山东省电力公司电力科学研究院 | Method and system for analyzing harmonic test error characteristics of extra-high voltage CVT |
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Patent Citations (3)
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| CN206258523U (en) * | 2016-06-07 | 2017-06-16 | 国网山东省电力公司 | A kind of distribution network electric energy quality monitoring device based on cloud platform |
| CN110763899A (en) * | 2019-10-23 | 2020-02-07 | 江苏中凌高科技股份有限公司 | Method and device for compensating harmonic voltage measurement error of Capacitor Voltage Transformer (CVT) |
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