CN112698260B - CVT voltage sag measurement error correction method and system - Google Patents
CVT voltage sag measurement error correction method and system Download PDFInfo
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Abstract
The invention provides a CVT voltage sag measurement error correction method and a system, wherein the method comprises the following steps: acquiring a primary side measurement current of a medium voltage transformer of a target CVT, a secondary side measurement voltage of the target CVT, an electrical parameter of the target CVT and a primary side measurement voltage of the target CVT; determining a secondary side compensation voltage of a target CVT according to the primary side measured current and the electrical parameter of the target CVT; determining a correction voltage of a target CVT according to the secondary side compensation voltage, the electrical parameter of the target CVT and the secondary side measurement voltage; the primary-side measured voltage of the target CVT is corrected based on the correction voltage. The CVT voltage sag measurement error correction method and system provided by the invention realize correction of the primary side measurement voltage of the target CVT based on the primary side measurement current of the medium-voltage transformer, and solve the problem of measurement error diversity caused by uncertainty of voltage sag.
Description
Technical Field
The invention belongs to the technical field of parameter correction, and particularly relates to a CVT voltage sag measurement error correction method and system.
Background
With the continuous transformation of domestic industry towards the direction of clustering, high-end and automation, the number of various sensitive electric equipment in a power grid is increased rapidly, and the severity of harm and economic loss caused by voltage sag is more and more prominent, so that the voltage sag becomes the most concerned and urgent electric energy quality problem in the current industry and academia. At present, electric energy quality monitoring is generally performed on 110kV and above power grids through a Capacitor Voltage Transformer (CVT), transient response of the CVT including an energy storage element inevitably affects development of research work such as characterization, disturbance identification, and transfer characteristics of Voltage sag, and analysis and correction of measurement errors of characteristic quantities of Voltage sag have important theoretical significance and practical value.
At present, CVT measurement error analysis mainly focuses on steady-state power quality, such as research on the influence of frequency, load, external temperature, electromagnetic environment and the like on CVT fundamental voltage measurement, and harmonic measurement error quantification and correction analysis are performed through experimental comparison and modeling simulation means. That is, the prior art has relatively lacked the study of transient power quality measurement errors such as voltage sag.
On the basis, the inventor of the application discovers the influence of a sag initial phase angle, residual voltage, CVT electrical parameters and the like on characteristic quantities such as the duration of voltage sag, a sag amplitude and phase jump of the voltage sag by means of constructing a simulation model and deducing errors of CVT measured voltage sag based on a CVT structure, and further provides a correction method of the CVT voltage sag measurement errors, so that the adverse effect of random state quantities such as the sag initial phase angle, the residual voltage, the CVT electrical parameters and the like on the voltage sag measurement is eliminated, and the correction of the CVT voltage sag measurement errors is realized.
Disclosure of Invention
The invention aims to provide a CVT voltage sag measurement error correction method and a CVT voltage sag measurement error correction system, so that adverse effects of random state quantities such as a sag initial phase angle, residual voltage, CVT electrical parameters and the like on voltage sag measurement are eliminated, and correction of the CVT voltage sag measurement error is realized.
In a first aspect of the embodiments of the present invention, a method for correcting errors in measurement of a voltage sag of a CVT is provided, including:
acquiring a primary side measurement current of a medium voltage transformer of a target CVT, a secondary side measurement voltage of the target CVT, an electrical parameter of the target CVT and a primary side measurement voltage of the target CVT;
determining a secondary side compensation voltage of a target CVT according to the primary side measured current and the electrical parameter of the target CVT;
determining a correction voltage of a target CVT according to the secondary side compensation voltage, the electrical parameters of the target CVT and the secondary side measurement voltage;
the primary-side measured voltage of the target CVT is corrected based on the correction voltage.
In a second aspect of the embodiments of the present invention, there is provided a CVT voltage sag measurement error correction system, including:
the current measuring module is used for measuring the primary side current of the medium voltage transformer of the target CVT to obtain the primary side measured current of the medium voltage transformer of the target CVT;
the voltage measuring module is used for measuring the secondary side voltage of the target CVT to obtain the secondary side measured voltage of the target CVT;
the virtual impedance compensation module is prestored with electrical parameters of a target CVT and used for acquiring a primary side measured current of a medium voltage transformer of the target CVT from the current measurement module, acquiring a secondary side measured voltage of the target CVT from the voltage measurement module and determining a secondary side compensation voltage of the target CVT according to the primary side measured current and the electrical parameters of the target CVT; determining a correction voltage of a target CVT according to the secondary side compensation voltage, the electrical parameter of the target CVT and the secondary side measurement voltage;
and the correction module is prestored with the primary side measurement voltage of the target CVT and is used for correcting the primary side measurement voltage of the target CVT based on the correction voltage.
In a third aspect of the embodiments of the present invention, there is provided a terminal device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, where the processor implements the steps of the CVT voltage sag measurement error correction method described above when executing the computer program.
In a fourth aspect of the embodiments of the present invention, a computer-readable storage medium is provided, which stores a computer program, and the computer program, when executed by a processor, implements the steps of the CVT voltage sag measurement error correction method described above.
The CVT voltage sag measurement error correction method and system provided by the embodiment of the invention have the beneficial effects that: the method carries out the calculation of the correction voltage based on the primary side measured current of the medium voltage transformer of the target CVT, and effectively eliminates the adverse effects of a sag initial phase angle, residual voltage and the like on the voltage sag measurement. On the basis, the invention also introduces the electrical parameters of the target CVT into the calculation of the correction voltage, and effectively eliminates the adverse effect of the randomness of the electrical parameters of the CVT on the voltage sag measurement. That is to say, the invention eliminates the adverse effect of random state quantities such as the initial phase angle of the sag, the residual voltage, the CVT electrical parameters and the like on the voltage sag measurement, and realizes the correction of the CVT voltage sag measurement error.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed for the embodiments or the prior art descriptions 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 flow chart of a CVT voltage sag measurement error correction method according to an embodiment of the present invention;
fig. 2 is a block diagram of a CVT voltage sag measurement error correction system according to an embodiment of the present invention;
fig. 3 is a schematic block diagram of a terminal device according to an embodiment of the present invention;
fig. 4 is a schematic structural diagram of a target CVT according to an embodiment of the present invention;
FIG. 5 is a schematic diagram illustrating correction of a CVT voltage sag measurement error according to an embodiment of the present invention;
FIG. 6 is a schematic diagram of an equivalent model of a CVT provided in accordance with an embodiment of the present invention;
fig. 7 is a schematic diagram of a simulation model of a measurement error of voltage sag caused by a power grid short circuit according to an embodiment of the present invention.
Detailed Description
In order to make the technical problems, technical solutions and advantageous effects to be solved by the present invention more clearly apparent, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
Referring to fig. 1, fig. 1 is a schematic flow chart of a CVT voltage sag measurement error correction method according to an embodiment of the present invention, where the method is applied to a capacitive voltage transformer, and fig. 4 is a schematic flow chart of the CVT voltage sag measurement error correction method, where the capacitive voltage transformer is composed of a capacitive voltage divider, a compensation reactor, a medium voltage transformer, a damper, and the like, and a high voltage system voltage passes through a capacitor C 1 、C 2 The voltage of the formed capacitive voltage divider is divided and then output u after secondary voltage reduction of a medium-voltage transformer o . In order to eliminate power frequency phase shift caused by the capacitive voltage divider, the power frequency phase shift needs to be in a zero internal resistance state at the power frequency through the compensation effect of the compensation reactor, even if the power frequency phase shift and the voltage dividing capacitor generate power frequency series resonance. The damper functions to suppress ferroresonance.
The CVT voltage sag measurement error correction method comprises the following steps:
s101: the primary side measurement current of a medium voltage transformer of the target CVT, the secondary side measurement voltage of the target CVT, the electrical parameter of the target CVT and the primary side measurement voltage of the target CVT are obtained.
In this embodiment, referring to fig. 5, the current collection module may be used to collect a primary-side current i of the medium voltage transformer of the target CVT, and then obtain a primary-side measured current i of the medium voltage transformer of the target CVT from the current collection module. Secondary side voltage u of target CVT (continuously variable transmission) can be acquired by using voltage acquisition module CVT And then obtaining the secondary side measurement of the target CVT from the voltage acquisition moduleVoltage u CVT . And finally, determining the correction voltage of the target CVT based on the primary side measured current of the medium voltage transformer of the target CVT and the secondary side measured voltage of the target CVT.
S102: and determining a secondary side compensation voltage of the target CVT according to the primary side measuring current and the electrical parameter of the target CVT.
In the present embodiment, the electrical parameters of the target CVT include a voltage transformation ratio of a medium voltage transformer of the target CVT, an equivalent capacitance of the target CVT, an equivalent inductance of the target CVT, and an equivalent resistance of the target CVT.
Determining a secondary side compensation voltage of the target CVT according to the primary side measured current and the electrical parameter of the target CVT, comprising:
and determining the primary side compensation voltage of the medium voltage transformer of the target CVT according to the primary side measured current, the equivalent capacitance of the target CVT, the equivalent inductance of the target CVT and the equivalent resistance of the target CVT.
A secondary side compensation voltage of the target CVT is determined based on a primary side compensation voltage of the medium voltage transformer and a transformation ratio of the medium voltage transformer.
S103: and determining the correction voltage of the target CVT according to the secondary side compensation voltage, the electrical parameter of the target CVT and the secondary side measurement voltage.
In this embodiment, the compensation voltage and the secondary side measured voltage of the target CVT can be superimposed based on the KVL theorem, and the correction voltage of the primary side of the target CVT can be obtained through the transformation ratio conversion of the target CVT.
In the present embodiment, the process of calculating the correction voltage in step S102 and step S103 is equivalent to adding a virtual impedance to the target CVT, that is, the essence of the embodiment of the present invention is to implement the correction of the primary-side measurement voltage of the target CVT by adding the virtual impedance.
S104: the primary-side measured voltage of the target CVT is corrected based on the correction voltage.
In the present embodiment, correcting the primary-side measured voltage of the target CVT based on the correction voltage includes:
and taking the difference value of the primary side measurement voltage and the correction voltage as the primary side voltage of the corrected target CVT.
As can be seen from the above description, the present invention performs the calculation of the correction voltage based on the primary side measured current of the medium voltage transformer of the target CVT, effectively eliminating the adverse effects of the sag initial phase angle, residual voltage, etc. on the voltage sag measurement. On the basis, the invention also introduces the electrical parameters of the target CVT into the calculation of the correction voltage, and effectively eliminates the adverse effect of the randomness of the electrical parameters of the target CVT on the measurement of the voltage sag. That is to say, the invention eliminates the adverse effect of random state quantities such as the initial phase angle of the sag, the residual voltage, the CVT electrical parameters and the like on the voltage sag measurement, and realizes the correction of the CVT voltage sag measurement error.
Optionally, as a specific implementation manner of the CVT voltage sag measurement error correction method provided by the embodiment of the present invention, determining the primary-side compensation voltage of the medium-voltage transformer of the target CVT according to the primary-side measurement current, the equivalent capacitance of the target CVT, the equivalent inductance of the target CVT, and the equivalent resistance of the target CVT includes:
wherein u is 1 A primary side compensation voltage of a medium voltage transformer of the target CVT, i is a primary side measurement current, C eq Is the equivalent capacitance of the target CVT, L eq Is the equivalent inductance, R, of the target CVT eq The equivalent resistance of the target CVT.
In this embodiment, referring to fig. 6, fig. 6 is a schematic diagram of an equivalent model of a target CVT provided by the embodiment of the present invention. The equivalent model of the target CVT may be first constructed, and then the electrical parameters of the target CVT may be determined based on the equivalent model of the target CVT. Wherein the equivalent capacitance of the target CVT, i.e., the equivalent capacitance of the capacitive divider, i.e., C eq Satisfies C eq ＝C 1 +C 2 Equivalent inductance L of the target CVT eq Equivalent resistance R of target CVT for compensating sum of leakage inductance of inductance and leakage inductance of medium voltage transformer eq For compensating the sum of the equivalent resistance of the reactor and the leakage resistance of the medium-voltage transformer, R f 、L f 、C f Is a parameter of the resonant damper, R d 、L d And n is the transformation ratio of the medium-voltage transformer.
Optionally, as a specific implementation manner of the CVT voltage sag measurement error correction method provided by the embodiment of the present invention, determining the secondary compensation voltage of the target CVT based on the primary compensation voltage of the medium voltage transformer and the transformation ratio of the medium voltage transformer includes:
wherein u is 2 Secondary side compensation voltage u of the target CVT 1 Is the primary side compensation voltage of the medium voltage transformer, and n is the transformation ratio of the medium voltage transformer.
Optionally, as a specific implementation manner of the CVT voltage sag measurement error correction method provided by the embodiment of the present invention, the electrical parameter of the target CVT includes a voltage transformation ratio of the target CVT.
Determining a correction voltage of the target CVT according to the secondary side compensation voltage, the electrical parameter of the target CVT and the secondary side measured voltage, comprising:
u ia ＝K×u 2
wherein u is ia Correction voltage, u, for the target CVT 2 K is the secondary side compensation voltage of the target CVT, and K is the transformation ratio of the target CVT.
Optionally, referring to fig. 7, as a specific implementation manner of the CVT voltage sag measurement error correction method provided by the embodiment of the present invention, the embodiment of the present invention may determine the influence factor of the CVT voltage sag measurement error based on the measurement error simulation model of the voltage sag caused by the power grid short circuit in fig. 7, and both the theoretical derivation and the simulation modeling analysis result indicate that the CVT voltage sag measurement error is a result of the combined action of internal and external factors, although the internal parameters of the CVT may be measured and determined by factory tests after the CVT is manufactured, the state quantity (initial angle, residual voltage, and the like) of the power grid at each voltage sag occurrence is an unpredictable random process, and such uncertainty finally causes that the voltage sag error has no specific rule to follow. Therefore, in addition to optimizing CVT parameters to reduce errors as much as possible, the present patent proposes a virtual impedance compensation-based CVT voltage sag measurement error correction method, that is, adding a virtual impedance compensation module (refer to fig. 5). After the virtual impedance compensation module is added, during simulation, other parameters are kept unchanged except that the initial phase angle of voltage sag is set to be 90 degrees, and time domain waveforms of all links during simulation indicate that the corrected primary side voltage is superposed with the voltage waveform of a primary system, so that the transient error caused by CVT can be effectively eliminated, and the problem of measurement error diversity caused by uncertainty of voltage sag is solved.
Fig. 2 is a block diagram of a CVT voltage sag measurement error correction system according to an embodiment of the present invention, which corresponds to the CVT voltage sag measurement error correction method according to the above embodiment. For convenience of explanation, only portions related to the embodiments of the present invention are shown. Referring to fig. 2, the CVT voltage sag measurement error correction system 20 includes: a current measurement module 21, a voltage measurement module 22, a virtual impedance compensation module 23, and a correction module 24.
The current measuring module 21 is configured to measure a primary side current of a medium voltage transformer of the target CVT to obtain a primary side measured current of the medium voltage transformer of the target CVT.
And the voltage measuring module 22 is used for measuring the secondary side voltage of the target CVT to obtain the secondary side measured voltage of the target CVT.
And the virtual impedance compensation module 23 is prestored with the electrical parameters of the target CVT, and is used for acquiring the primary side measured current of the medium voltage transformer of the target CVT from the current measurement module, acquiring the secondary side measured voltage of the target CVT from the voltage measurement module, and determining the secondary side compensation voltage of the target CVT according to the primary side measured current and the electrical parameters of the target CVT. And determining the correction voltage of the target CVT according to the secondary side compensation voltage, the electrical parameter of the target CVT and the secondary side measurement voltage.
The correction module 24 prestores a primary-side measured voltage of the target CVT, and corrects the primary-side measured voltage of the target CVT based on the correction voltage.
Optionally, as a specific implementation manner of the CVT voltage sag measurement error correction system provided in the embodiment of the present invention, the current measurement module is a current sensor, and the voltage measurement module is a voltage sensor.
Optionally, as a specific implementation manner of the CVT voltage sag measurement error correction system provided by the embodiment of the present invention, the electrical parameters of the target CVT include a voltage transformation ratio of a medium voltage transformer of the target CVT, an equivalent capacitance of the target CVT, an equivalent inductance of the target CVT, and an equivalent resistance of the target CVT.
Determining a secondary side compensation voltage of the target CVT according to the primary side measured current and the electrical parameter of the target CVT, comprising:
and determining the primary side compensation voltage of the medium voltage transformer of the target CVT according to the primary side measured current, the equivalent capacitance of the target CVT, the equivalent inductance of the target CVT and the equivalent resistance of the target CVT.
A secondary side compensation voltage of the target CVT is determined based on a primary side compensation voltage of the medium voltage transformer and a transformation ratio of the medium voltage transformer.
Optionally, as a specific implementation manner of the CVT voltage sag measurement error correction system provided by the embodiment of the present invention, the determining the primary-side compensation voltage of the medium-voltage transformer of the target CVT according to the primary-side measurement current, the equivalent capacitance of the target CVT, the equivalent inductance of the target CVT, and the equivalent resistance of the target CVT includes:
wherein u is 1 A primary side compensation voltage of a medium voltage transformer of the target CVT, i is a primary side measurement current, C eq Is the equivalent capacitance of the target CVT, L eq Is the equivalent inductance, R, of the target CVT eq The equivalent resistance of the target CVT.
Optionally, as a specific implementation manner of the CVT voltage sag measurement error correction system provided in the embodiment of the present invention, the determining a secondary side compensation voltage of a target CVT based on a primary side compensation voltage of a medium voltage transformer and a transformation ratio of the medium voltage transformer includes:
wherein u is 2 Secondary side compensation voltage u of the target CVT 1 Is the primary side compensation voltage of the medium voltage transformer, and n is the transformation ratio of the medium voltage transformer.
Optionally, as a specific implementation manner of the CVT voltage sag measurement error correction system provided by the embodiment of the present invention, the electrical parameter of the target CVT includes a voltage transformation ratio of the target CVT.
Determining a correction voltage of the target CVT according to the secondary side compensation voltage, the electrical parameter of the target CVT and the secondary side measured voltage, comprising:
u ia ＝K×u 2
wherein u is ia Correction voltage, u, for a target CVT 2 K is a secondary side compensation voltage of the target CVT, and K is a transformation ratio of the target CVT.
Optionally, as a specific implementation manner of the CVT voltage sag measurement error correction system provided in the embodiment of the present invention, the correcting the primary-side measured voltage of the target CVT based on the correction voltage includes:
and taking the difference value of the primary side measurement voltage and the correction voltage as the primary side voltage of the corrected target CVT.
Referring to fig. 3, fig. 3 is a schematic block diagram of a terminal device according to an embodiment of the present invention. The terminal 300 in the present embodiment as shown in fig. 3 may include: one or more processors 301, one or more input devices 302, one or more output devices 303, and one or more memories 304. The processor 301, the input device 302, the output device 303 and the memory 304 are all in communication with each other via a communication bus 305. The memory 304 is used to store a computer program comprising program instructions. Processor 301 is operative to execute program instructions stored in memory 304. Wherein the processor 301 is configured to call program instructions to perform the following functions for operating the modules/units in the above-described device embodiments, such as the functions of the modules 21 to 24 shown in fig. 2.
It should be understood that, in the embodiment of the present invention, the Processor 301 may be a Central Processing Unit (CPU), and the Processor may also be other general-purpose processors, Digital Signal Processors (DSPs), Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs) or other Programmable logic devices, discrete Gate or transistor logic devices, discrete hardware components, and the like. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.
The input device 302 may include a touch pad, a fingerprint sensor (for collecting fingerprint information of a user and direction information of the fingerprint), a microphone, etc., and the output device 303 may include a display (LCD, etc.), a speaker, etc.
The memory 304 may include both read-only memory and random-access memory and provides instructions and data to the processor 301. A portion of the memory 304 may also include non-volatile random access memory. For example, the memory 304 may also store device type information.
In a specific implementation, the processor 301, the input device 302, and the output device 303 described in this embodiment of the present invention may execute the implementation manners described in the first embodiment and the second embodiment of the CVT voltage sag measurement error correction method provided in this embodiment of the present invention, and may also execute the implementation manners of the terminal described in this embodiment of the present invention, which is not described herein again.
In another embodiment of the present invention, a computer-readable storage medium is provided, where a computer program is stored, and the computer program includes program instructions, and when the program instructions are executed by a processor, all or part of the processes in the method of the above embodiments are implemented by a computer program instructing related hardware, and the computer program may be stored in a computer-readable storage medium, and when the computer program is executed by a processor, the steps of the above method embodiments are implemented. Wherein the computer program comprises computer program code, which may be in the form of source code, object code, an executable file or some intermediate form, etc. The computer readable medium may include: any entity or device capable of carrying computer program code, recording medium, U.S. disk, removable hard disk, magnetic disk, optical disk, computer Memory, Read-Only Memory (ROM), Random Access Memory (RAM), electrical carrier wave signals, telecommunications signals, software distribution media, and the like. It should be noted that the computer readable medium may include any suitable increase or decrease as required by legislation and patent practice in the jurisdiction, for example, in some jurisdictions, computer readable media may not include electrical carrier signals and telecommunications signals in accordance with legislation and patent practice.
The computer readable storage medium may be an internal storage unit of the terminal of any of the foregoing embodiments, for example, a hard disk or a memory of the terminal. The computer readable storage medium may also be an external storage device of the terminal, such as a plug-in hard disk provided on the terminal, a Smart Media Card (SMC), a Secure Digital (SD) Card, a Flash memory Card (Flash Card), and the like. Further, the computer-readable storage medium may also include both an internal storage unit and an external storage device of the terminal. The computer-readable storage medium is used for storing a computer program and other programs and data required by the terminal. The computer-readable storage medium may also be used to temporarily store data that has been output or is to be output.
Those of ordinary skill in the art will appreciate that the elements and algorithm steps of the examples described in connection with the embodiments disclosed herein may be embodied in electronic hardware, computer software, or combinations of both, and that the components and steps of the examples have been described in a functional general in the foregoing description for the purpose of illustrating clearly the interchangeability of hardware and software. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.
It can be clearly understood by those skilled in the art that, for convenience and brevity of description, the specific working processes of the terminal and the unit described above may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.
In the several embodiments provided in the present application, it should be understood that the disclosed terminal and method can be implemented in other manners. For example, the above-described apparatus embodiments are merely illustrative, and for example, a division of a unit is merely a logical division, and an actual implementation may have another division, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces or units, and may also be an electrical, mechanical or other form of connection.
Units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment of the present invention.
In addition, functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.
While the invention has been described with reference to specific embodiments, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (6)
1. A CVT voltage sag measurement error correction method is characterized by comprising the following steps:
acquiring a primary side measurement current of a medium voltage transformer of a target CVT, a secondary side measurement voltage of the target CVT, an electrical parameter of the target CVT and a primary side measurement voltage of the target CVT, wherein the electrical parameter of the target CVT comprises a voltage transformation ratio of the medium voltage transformer of the target CVT, an equivalent capacitance of the target CVT, an equivalent inductance of the target CVT and an equivalent resistance of the target CVT;
determining a secondary side compensation voltage of a target CVT according to the primary side measured current and the electrical parameter of the target CVT, comprising:
determining a primary side compensation voltage of a medium voltage transformer of the target CVT according to the primary side measurement current, the equivalent capacitance of the target CVT, the equivalent inductance of the target CVT and the equivalent resistance of the target CVT, and the method comprises the following steps:
wherein u is 1 A primary side compensation voltage of a medium voltage transformer of the target CVT, i is the primary side measurement current, C eq Is the equivalent capacitance of the target CVT, L eq Is the equivalent inductance, R, of the target CVT eq Is the equivalent resistance of the target CVT;
determining a secondary side compensation voltage of a target CVT based on a primary side compensation voltage of the medium voltage transformer and a transformation ratio of the medium voltage transformer, comprising:
wherein u is 2 Secondary side compensation voltage u of the target CVT 1 Compensating voltage for the primary side of the medium voltage transformer, wherein n is the transformation ratio of the medium voltage transformer;
determining a correction voltage for a target CVT from the secondary-side compensation voltage, the electrical parameter of the target CVT, and the secondary-side measured voltage, comprising:
u ia ＝K×u 2
wherein u is ia Correction voltage, u, for a target CVT 2 A secondary side compensation voltage of a target CVT is obtained, and K is a transformation ratio of the target CVT;
the primary-side measured voltage of the target CVT is corrected based on the correction voltage.
2. The CVT voltage sag measurement error correction method of claim 1, wherein the correcting the primary-side measurement voltage of the target CVT based on the correction voltage comprises:
and taking the difference value of the primary side measurement voltage and the correction voltage as the primary side voltage of the corrected target CVT.
3. A CVT voltage sag measurement error correction system, comprising:
the current measuring module is used for measuring the primary side current of the medium voltage transformer of the target CVT to obtain the primary side measured current of the medium voltage transformer of the target CVT;
the voltage measuring module is used for measuring the secondary side voltage of the target CVT to obtain the secondary side measured voltage of the target CVT;
the virtual impedance compensation module is used for prestoring the electrical parameters of the target CVT, wherein the electrical parameters of the target CVT comprise the voltage transformation ratio of a medium voltage transformer of the target CVT, the equivalent capacitance of the target CVT, the equivalent inductance of the target CVT and the equivalent resistance of the target CVT; the method for obtaining a primary side measurement current of a medium voltage transformer of a target CVT from a current measurement module, obtaining a secondary side measurement voltage of the target CVT from a voltage measurement module, and determining a secondary side compensation voltage of the target CVT according to the primary side measurement current and an electrical parameter of the target CVT includes: determining a primary side compensation voltage of a medium voltage transformer of the target CVT according to the primary side measurement current, the equivalent capacitance of the target CVT, the equivalent inductance of the target CVT and the equivalent resistance of the target CVT, and the method comprises the following steps:
wherein u is 1 A primary side compensation voltage of a medium voltage transformer of the target CVT, i is the primary side measurement current, C eq Is the equivalent capacitance of the target CVT, L eq Is the equivalent inductance, R, of the target CVT eq Is the equivalent resistance of the target CVT;
determining a secondary side compensation voltage of a target CVT based on a primary side compensation voltage of the medium voltage transformer and a transformation ratio of the medium voltage transformer, comprising:
wherein u is 2 Secondary side compensation voltage u of the target CVT 1 Compensating voltage for the primary side of the medium voltage transformer, wherein n is the transformation ratio of the medium voltage transformer;
determining a correction voltage for a target CVT from the secondary-side compensation voltage, the electrical parameter of the target CVT, and the secondary-side measured voltage, comprising:
u ia ＝K×u 2
wherein u is ia Correction voltage, u, for a target CVT 2 Is a secondary side compensation voltage of a target CVT, and K is a transformation ratio of the target CVT;
and the correction module is prestored with the primary side measurement voltage of the target CVT and is used for correcting the primary side measurement voltage of the target CVT based on the correction voltage.
4. The CVT voltage sag measurement error correction system of claim 3, wherein the current measurement module is a current sensor and the voltage measurement module is a voltage sensor.
5. A terminal device comprising a memory, a processor and a computer program stored in the memory and executable on the processor, characterized in that the processor implements the steps of the method according to any of claims 1 to 2 when executing the computer program.
6. A computer-readable storage medium, in which a computer program is stored which, when being executed by a processor, carries out the steps of the method according to any one of claims 1 to 2.
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