CN116908540A - Frequency spectrum transfer characteristic test system and test method - Google Patents

Frequency spectrum transfer characteristic test system and test method Download PDF

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Publication number
CN116908540A
CN116908540A CN202310861540.8A CN202310861540A CN116908540A CN 116908540 A CN116908540 A CN 116908540A CN 202310861540 A CN202310861540 A CN 202310861540A CN 116908540 A CN116908540 A CN 116908540A
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CN
China
Prior art keywords
voltage
capacitor
current
medium
frequency spectrum
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CN202310861540.8A
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Chinese (zh)
Inventor
武霁阳
彭光强
国建宝
邵震
陈名
陈潜
黄义隆
陈礼昕
黄之笛
龚泽
丘子岳
邹延生
杨育丰
刘军成
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China Southern Power Grid Corp Ultra High Voltage Transmission Co Electric Power Research Institute
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China Southern Power Grid Corp Ultra High Voltage Transmission Co Electric Power Research Institute
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Priority to CN202310861540.8A priority Critical patent/CN116908540A/en
Publication of CN116908540A publication Critical patent/CN116908540A/en
Pending legal-status Critical Current

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R23/00—Arrangements for measuring frequencies; Arrangements for analysing frequency spectra
    • G01R23/16—Spectrum analysis; Fourier analysis
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R35/00—Testing or calibrating of apparatus covered by the other groups of this subclass
    • G01R35/02—Testing or calibrating of apparatus covered by the other groups of this subclass of auxiliary devices, e.g. of instrument transformers according to prescribed transformation ratio, phase angle, or wattage rating

Abstract

The application relates to a frequency spectrum transfer characteristic test system and a test method, which are used for testing the frequency spectrum transfer characteristic of a capacitive voltage transformer. The system comprises: a load; the capacitor voltage transformer comprises a high-voltage capacitor, a medium-voltage capacitor and an electromagnetic unit, wherein the high-voltage capacitor is connected with a high-voltage power system and the medium-voltage capacitor, the medium-voltage capacitor is connected with a first grounding end, a medium-voltage end is formed between the high-voltage capacitor and the medium-voltage capacitor, a ground potential end is formed between the medium-voltage capacitor and the first grounding end, and the electromagnetic unit is connected with the medium-voltage end, the ground potential end, a first end of a load and a second end of the load; the harmonic source is connected with the medium voltage end and the first grounding end; the first current sensor is arranged between the first grounding end and the ground potential end; and a second current sensor arranged between the medium voltage capacitor and the ground potential end. The frequency spectrum transfer characteristic test system provided by the application enables the frequency spectrum transfer characteristic test of the capacitive voltage transformer to be simply and conveniently realized.

Description

Frequency spectrum transfer characteristic test system and test method
Technical Field
The application relates to the technical field of capacitive voltage transformers, in particular to a frequency spectrum transfer characteristic test system and a frequency spectrum transfer characteristic test method.
Background
In recent years, with the construction of a novel power system mainly comprising new energy, large-scale new energy power generation is integrated into a high-voltage and ultra-high-voltage power system; and a plurality of high-voltage and ultrahigh-voltage alternating-current and direct-current series-parallel systems are put into operation. The series of changes lead to abnormal severe electromagnetic environment of the high-voltage and ultra-high-voltage power system, and the electric energy quality disturbance level taking harmonic waves as a main body is urgently needed to be grasped, so that technical support is provided for the healthy development of the novel power system. However, the transformer for sensing the operating voltage of the high-voltage and ultra-high-voltage power system mainly comprises a capacitive voltage transformer, and it is recognized that the capacitive voltage transformer cannot correctly transmit harmonic waves and ultra-high frequency components.
In order to accurately sense the harmonic waves of the high-voltage and ultra-high-voltage systems, the frequency spectrum transfer characteristics of the capacitive voltage transformer need to be tested in advance, and accordingly the harmonic voltage level measured through the secondary side of the capacitive voltage transformer is corrected.
However, the current harmonic source voltage level range is basically between hundreds of volts and tens of kilovolts, and the harmonic source for measuring the frequency spectrum transfer characteristic of the 35 kV-1000 kV high-voltage and ultra-high-voltage capacitive voltage transformer is lacking.
Disclosure of Invention
Based on the above, it is necessary to provide a system and a method for testing the frequency spectrum transfer characteristic, aiming at the technical problem that the harmonic source voltage cannot be directly connected to the high voltage position of the capacitive voltage transformer for testing.
In a first aspect, the present application provides a system for testing spectral transfer characteristics of a capacitive voltage transformer. The system comprises:
a load comprising a first end and a second end;
the capacitor voltage transformer comprises a high-voltage capacitor, a medium-voltage capacitor and an electromagnetic unit, wherein a first end of the high-voltage capacitor is used for being connected with a high-voltage power system, a second end of the high-voltage capacitor is connected with a first end of the medium-voltage capacitor, a second end of the medium-voltage capacitor is connected with a first grounding end, a medium-voltage end is formed between the high-voltage capacitor and the medium-voltage capacitor, a ground potential end is formed between the medium-voltage capacitor and the first grounding end, a first end of the electromagnetic unit is connected with the medium-voltage end, a second end of the electromagnetic unit is connected with the ground potential end, a third end of the electromagnetic unit is connected with a first end of a load, and a fourth end of the electromagnetic unit is connected with a second end of the load;
a first end of the harmonic source is connected with the medium voltage end, and a second end of the harmonic source is connected with the first grounding end;
the first current sensor is arranged between the first grounding end and the ground potential end; and
and the second current sensor is arranged between the second end of the medium-voltage capacitor and the ground potential end.
In one embodiment, the fundamental voltage of the harmonic source output spectrum is determined from the rated voltage of the medium voltage capacitor.
In one embodiment, the second end of the load is also connected to a second ground.
In one embodiment, a control switch is provided between the harmonic source and the medium voltage terminal.
In one embodiment, the system further comprises a harmonic analyzer, wherein the first current sensor, the second current sensor and the load are all connected with the harmonic analyzer, and the harmonic analyzer is used for acquiring a first current obtained by the first current sensor, a second current obtained by the second current sensor and a secondary side voltage of the load.
In one embodiment, the system further comprises a processor for:
acquiring a first capacitor of a high-voltage capacitor, acquiring a second capacitor of a medium-voltage capacitor, and acquiring rated voltage of the medium-voltage capacitor;
determining fundamental wave voltage of the output frequency spectrum of the harmonic source according to the rated voltage;
acquiring a first current, a second current and a secondary side voltage obtained by a harmonic analyzer under an output frequency spectrum based on fundamental wave voltage;
determining an equivalent primary side voltage according to the first capacitor, the first current, the second capacitor and the second current;
and determining the frequency spectrum transfer characteristic of the capacitive voltage transformer according to the equivalent primary side voltage and the secondary side voltage.
In one embodiment, the harmonic analyzer has a recording interval, and the first current, the second current, and the secondary side voltage acquired by the harmonic analyzer are all in series.
In a second aspect, the present application further provides a method for testing spectral transfer characteristics, by using the system for testing spectral transfer characteristics, for testing spectral transfer characteristics of a capacitive voltage transformer. The method comprises the following steps:
acquiring a first capacitor of a high-voltage capacitor, acquiring a second capacitor of a medium-voltage capacitor, and acquiring rated voltage of the medium-voltage capacitor;
determining fundamental wave voltage of the output frequency spectrum of the harmonic source according to the rated voltage;
acquiring a first current obtained by a first current sensor, a second current obtained by a second current sensor and a secondary side voltage of a load under an output frequency spectrum based on fundamental wave voltage;
determining an equivalent primary side voltage according to the first capacitor, the first current, the second capacitor and the second current;
and determining the frequency spectrum transfer characteristic of the capacitive voltage transformer according to the equivalent primary side voltage and the secondary side voltage.
In one embodiment, acquiring a first current obtained by a first current sensor, a second current obtained by a second current sensor, and a secondary side voltage of a load in an output spectrum based on a fundamental voltage, includes:
acquiring a first current sequence obtained by a first current sensor, a second current sequence obtained by a second current sensor and a secondary side voltage sequence of a load at each moment under an output frequency spectrum based on fundamental wave voltage;
determining an equivalent primary-side voltage from the first capacitance, the first current, the second capacitance, and the second current, comprising:
determining an equivalent primary voltage sequence according to the first capacitor, the second capacitor, the first current sequence and the second current sequence;
determining the spectral transfer characteristics of the capacitive voltage transformer from the equivalent primary and secondary voltages, comprising:
and determining the frequency spectrum transfer characteristic of the capacitive voltage transformer according to the equivalent primary voltage sequence and the secondary side voltage sequence.
In one embodiment, determining the spectral transfer characteristics of the capacitive voltage transformer from the equivalent primary and secondary side voltage sequences includes:
determining a transfer characteristic sequence of the capacitive voltage transformer at each moment according to the equivalent primary voltage sequence and the secondary side voltage sequence;
and averaging the transfer characteristic sequences to obtain the frequency spectrum transfer characteristic of the capacitive voltage transformer.
According to the frequency spectrum transfer characteristic test system and the frequency spectrum transfer characteristic test method, after harmonic waves are provided by the harmonic source, the voltage input to the high-voltage capacitor can be determined according to the first current and the second current and the capacitance of the high-voltage capacitor and the capacitance of the medium-voltage capacitor, so that the frequency spectrum transfer characteristic of the capacitor type voltage transformer can be determined according to the voltage on the load and the voltage input to the high-voltage capacitor. The frequency spectrum transfer characteristic test system provided by the application enables the frequency spectrum transfer characteristic test of the capacitive voltage transformer to be simply and conveniently realized.
Drawings
FIG. 1 is a schematic diagram of a spectrum transfer characteristic testing system in one embodiment;
FIG. 2 is a graph of amplitude versus frequency characteristics of a capacitive voltage transformer according to one embodiment;
FIG. 3 is a graph of phase difference versus frequency for a capacitive voltage transformer in one embodiment;
FIG. 4 is a flow chart of a method of testing spectral transfer characteristics in one embodiment.
Detailed Description
In order that the above objects, features and advantages of the application will be readily understood, a more particular description of the application will be rendered by reference to the appended drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. The present application may be embodied in many other forms than described herein and similarly modified by those skilled in the art without departing from the spirit of the application, whereby the application is not limited to the specific embodiments disclosed below.
In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings are merely for convenience in describing the present application and simplifying the description, and do not indicate or imply that the device or element being referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present application.
Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present application, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.
In the present application, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; either directly or indirectly, through intermediaries, or both, may be in communication with each other or in interaction with each other, unless expressly defined otherwise. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art according to the specific circumstances.
In the present application, unless expressly stated or limited otherwise, a first feature "up" or "down" a second feature may be the first and second features in direct contact, or the first and second features in indirect contact via an intervening medium. Moreover, a first feature being "above," "over" and "on" a second feature may be a first feature being directly above or obliquely above the second feature, or simply indicating that the first feature is level higher than the second feature. The first feature being "under", "below" and "beneath" the second feature may be the first feature being directly under or obliquely below the second feature, or simply indicating that the first feature is less level than the second feature.
It will be understood that when an element is referred to as being "fixed" or "disposed" on another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like are used herein for illustrative purposes only and are not meant to be the only embodiment.
Referring to fig. 1, fig. 1 is a schematic diagram of a spectrum transfer characteristic testing system according to an embodiment of the application, where the spectrum transfer characteristic testing system is used for testing the spectrum transfer characteristic of a capacitive voltage transformer. An embodiment of the present application provides a spectrum transfer characteristic test system, which includes a capacitive voltage transformer 100, a harmonic source 200, a load 300, a first current sensor 400, and a second current sensor 500. The capacitive voltage transformer 100 is a test object of spectrum transfer characteristics, and includes a high voltage capacitor 110, a medium voltage capacitor 120, and an electromagnetic unit 130, where the high voltage capacitor 110 and the medium voltage capacitor 120 are used for dividing voltages, and the electromagnetic unit 130 is used for measuring voltages and converting the voltages into electrical signals that can enter a meter for measurement. The harmonic source 200 is used for emitting harmonic waves, the first current sensor 400 is used for detecting the total current of the capacitive voltage transformer 100 grounded, and the second current sensor 500 is used for detecting the current of the medium voltage capacitor 120.
Specifically, a first end of the high voltage capacitor 110 is used to connect to a high voltage power system, and a second end of the high voltage capacitor 110 is connected to a first end of the medium voltage capacitor 120.
In a high-voltage power system, a capacitive voltage transformer is usually installed at a high-voltage side, and is used for reducing a high-voltage signal into a signal with a lower voltage, and outputting the signal to equipment such as protection, metering and the like for processing. High voltage power system refers to a power system for delivering, distributing and transmitting high voltage electrical energy. Typically, high voltage power systems are used for high capacity power transmission and distribution to meet the electricity demands of urban, industrial and rural areas. In this embodiment, the high voltage power system may be a power system with a voltage of 35kV to 1000 kV.
The second terminal of the medium voltage capacitor 120 is connected to the first ground terminal 121, a medium voltage terminal 122 is formed between the high voltage capacitor 110 and the medium voltage capacitor 120, and a ground potential terminal 123 is formed between the medium voltage capacitor 120 and the first ground terminal 121. The first ground terminal 121 is grounded.
When there is a voltage on the high voltage system, the high voltage capacitor 110 and the medium voltage capacitor 120 form a voltage dividing loop, and the electromagnetic unit 130 further reduces the medium voltage to a lower voltage that can directly enter the meter.
Harmonic source 200 is a device or apparatus that generates a harmonic current or a harmonic voltage. Typically, the voltage level of harmonic source 200 ranges substantially between a few hundred volts and a few tens of kilovolts.
In this embodiment, a first end of the harmonic source 200 is connected to the medium voltage end 122, and a second end of the harmonic source 200 is connected to the first ground end 121. In one possible implementation, a control switch 210 is provided between the first end of the harmonic source 200 and the medium voltage end 122, the control switch 210 being used to control the passage and opening of the branch. When the control switch 210 is opened, the harmonic source 200 cannot supply power to the medium voltage capacitor 120, and only when the control switch 210 is closed, the harmonic source 200 can supply power to the medium voltage capacitor 120, so that the test of the frequency spectrum transfer characteristic curve of the capacitive voltage transformer 100 is completed.
In the case where the high-voltage capacitor 110 is not connected to the high-voltage power system, the harmonic wave emitted from the harmonic source 200 is input to the medium-voltage capacitor 120. Based on the principle of voltage division of the capacitor, when the first end of the high voltage capacitor 110 is connected to the high voltage power system, the high voltage capacitor 110 can carry several tens to thousands of kilovolts, so that the medium voltage capacitor 120 only carries several kilovolts or several tens of kilovolts. Therefore, the potential difference between the medium voltage terminal 122 and the ground potential terminal 123 is several kv or tens kv, and at this time, an equal voltage can be applied through the harmonic source 200, which is equivalent to that of the high voltage capacitor 110 connected to the high voltage power system. This is because the electric potential generated at the medium voltage terminal 122 is the same in the case of switching in the harmonic source 200 and switching in the high voltage power system, and therefore it is practically significant to detect the spectral transfer characteristics of the capacitive voltage transformer by generating harmonics by the harmonic source 200.
The load 300 is on the secondary side, a first end of the load 300 is connected to the third end of the electromagnetic unit 130, and a second end of the load 300 is connected to the fourth end of the electromagnetic unit 130. Thus, the voltage generated by the harmonic source 200 is also transferred to the load 300. In one possible implementation, the second end of the load 300 may also be connected to a second ground 310, protecting personnel and equipment.
The electromagnetic unit 130 is a critical component of the capacitive voltage sensor 100, typically consisting of one or more coils, which contain one or more turns. When the current in the circuit under test passes through the electromagnetic unit, a magnetic field is generated around the coil. A first end of the electromagnetic unit 130 is connected to the medium voltage terminal 122, a second end of the electromagnetic unit 130 is connected to the ground potential terminal 123, a third end of the electromagnetic unit 130 is connected to the first end of the load 300, and a fourth end of the electromagnetic unit 130 is connected to the second end of the load 300.
The first current sensor 400 is disposed between the first ground terminal 121 and the ground potential terminal 123. The second current sensor 500 is disposed between the second terminal of the medium voltage capacitor 120 and the ground terminal 123. When the harmonic source 200 applies a harmonic, the first current sensor 400 obtains a first current and the second current sensor 500 obtains a second current.
In this embodiment, by using the spectrum transfer characteristic test system, after the harmonic wave is provided by the harmonic source, the voltage input to the high-voltage capacitor can be determined according to the first current and the second current and the capacitances of the high-voltage capacitor and the medium-voltage capacitor, and the voltage is used as the equivalent primary side voltage, so that the spectrum transfer characteristic of the capacitor voltage transformer can be determined according to the voltage on the load and the voltage input to the high-voltage capacitor. The frequency spectrum transfer characteristic system provided by the application enables the frequency spectrum transfer characteristic test of the capacitive voltage transformer to be possible.
In one embodiment, the spectrum transfer characteristic testing system may further include a harmonic analyzer (not shown in the drawing), to which the first current sensor 400, the second current sensor 500, and the load 300 are connected.
A harmonic analyzer is an instrument for measuring and analyzing harmonic components in an electric power system, capable of measuring voltage and current waveforms in the electric power system and converting these waveforms into harmonic spectrums by fourier transform. The amplitude, phase, frequency and other information of each harmonic component in the voltage and the current can be obtained through the harmonic analyzer.
In addition, the harmonic analyzer can also display the results of harmonic data, including harmonic spectrograms, waveform diagrams, numerical parameters and the like. In this embodiment, the harmonic analyzer is used to obtain the first current obtained by the first current sensor 400, the second current obtained by the second current sensor 500, and the secondary side voltage of the load 300.
In one possible implementation, the harmonic analyzer has a recording interval, and the first current, the second current, and the secondary side voltage acquired by the harmonic analyzer are all sequences. For example, the secondary side voltage sequence of the capacitive voltage transformer is read and recorded as { V ] O,1 ，V O,2 ，V O,3 ...V O,k }，V O,k The secondary side voltage sequences of the capacitive voltage transformer at the moment k (each sequence comprises a frequency spectrum of each subharmonic).
In this embodiment, the first current sensor, the second current sensor and the load are connected to a harmonic analyzer, and the first current, the second current and the secondary side voltage are obtained by the harmonic analyzer. In this way, the voltage change of the load in response to the harmonic source can be accurately acquired, and the high voltage input to the high voltage capacitor can be determined by the first current and the second current.
In one embodiment, the spectral transfer characteristic testing system further includes a processor (not shown) that can be used for the computational processing. The processor is specifically configured to: acquiring a first capacitance of the high-voltage capacitor 110, acquiring a second capacitance of the medium-voltage capacitor 120, and acquiring a rated voltage of the medium-voltage capacitor 120; determining a fundamental voltage of the output spectrum of the harmonic source 200 according to the rated voltage; acquiring a first current, a second current and a secondary side voltage obtained by a harmonic analyzer under an output frequency spectrum based on fundamental wave voltage; determining an equivalent primary side voltage according to the first capacitor, the first current, the second capacitor and the second current; the spectral transfer characteristics of the capacitive voltage transformer 100 are determined from the equivalent primary and secondary side voltages.
After the harmonic analyzer obtains the first current, the second current and the secondary side voltage, the processor performs calculation processing. The first capacitance is the capacitance of the high voltage capacitor 110 and the second capacitance is the capacitance of the medium voltage capacitor 120. The rated voltage of the medium voltage capacitor 120 is the voltage value that the medium voltage capacitor 120 is subjected to under normal operating conditions. The output spectrum of the harmonic source 200 is based on the same or similar frequency spectrum of the fundamental voltage as the rated voltage of the medium voltage capacitor 120.
The processor may determine the voltage input to the high voltage capacitor, i.e., the equivalent primary side voltage, according to equation (1).
Wherein the harmonic source 200 emits an output spectrum having an angular frequency ω;is the equivalent primary side voltage; />The first current measured by the first current sensor 400 is regarded as an equivalent current flowing through the high voltage capacitor 110; />Is the second current measured by the second current sensor 500, i.e. the actual current flowing through the medium voltage capacitor 120; jX C2 (jω) is the capacitive reactance of the medium voltage capacitor, jX C1 (jω) is the capacitive reactance of the high voltage capacitor.
In determining the equivalent primary-side voltageThe spectral transfer characteristics of the capacitive voltage transformer 100 may then be determined according to equation (2).
Where G (jω) is the spectral transfer characteristic of the capacitive voltage transformer 100 corresponding to the ω spectrum,is corresponding to omega spectrumIs set in the voltage domain of the battery.
Taking a capacitive voltage transformer with a voltage class of 110kV as an example, the parameters are as follows: load C N First capacitor C of=20000 pF, high voltage capacitor 1 Second capacitor C of medium voltage capacitor = 26180pF 2 = 84680pF, and the medium voltage rated phase voltage of the capacitive voltage transformer is calculated to be 15kV by the above parameters. A 15kV voltage class harmonic source was selected for testing. According to the wiring test of fig. 1, the obtained frequency spectrum transfer characteristic of the capacitive voltage transformer is shown in fig. 2 and 3, fig. 2 is a graph of amplitude-frequency characteristic versus frequency, and fig. 3 is a graph of CVT phase difference versus frequency, wherein CVT is the capacitive voltage transformer. The system for the frequency spectrum transfer characteristic of the capacitive voltage transformer can obtain the accurate frequency spectrum transfer characteristic of the capacitive voltage transformer.
In this embodiment, the output spectrum of the harmonic source is determined by the rated voltage of the medium-voltage capacitor, and after the first current, the second current and the secondary side voltage are obtained by the harmonic analyzer under the output spectrum, the processor determines the equivalent primary side voltage according to the first capacitor of the high-voltage capacitor, the second capacitor of the medium-voltage capacitor, the first current and the second current, so that the spectrum transfer characteristic of the capacitive voltage transformer can be determined by the secondary side voltage and the equivalent primary side voltage.
As shown in fig. 4, in one embodiment, a method for testing spectral transfer characteristics of a capacitive voltage transformer by using the spectral transfer characteristic testing system includes the following steps:
s402, acquiring a first capacitor of the high-voltage capacitor, acquiring a second capacitor of the medium-voltage capacitor, and acquiring rated voltage of the medium-voltage capacitor.
S404, determining fundamental wave voltage of the output frequency spectrum of the harmonic source according to the rated voltage.
S406, acquiring a first current obtained by the first current sensor, a second current obtained by the second current sensor and a secondary side voltage of the load under an output frequency spectrum based on the fundamental voltage.
S408, determining the equivalent primary side voltage according to the first capacitor, the first current, the second capacitor and the second current.
S410, determining the frequency spectrum transfer characteristic of the capacitive voltage transformer according to the equivalent primary side voltage and the secondary side voltage.
The output frequency spectrum of the harmonic source is determined through the rated voltage of the medium-voltage capacitor, after the first current obtained by the first current sensor, the second current obtained by the second current sensor and the secondary side voltage of the load under the output frequency spectrum are obtained, the equivalent primary side voltage is determined according to the first capacitor of the high-voltage capacitor, the second capacitor of the medium-voltage capacitor, the first current and the second current, and the frequency spectrum transfer characteristic of the capacitor voltage transformer can be determined through the secondary side voltage and the equivalent primary side voltage.
In one embodiment, the step of obtaining the first current obtained by the first current sensor, the second current obtained by the second current sensor, and the secondary side voltage of the load in the output spectrum in S406 includes: acquiring a first current sequence obtained by a first current sensor, a second current sequence obtained by a second current sensor and a secondary side voltage sequence of a load at each moment under an output frequency spectrum based on fundamental wave voltage; and determining an equivalent primary-side voltage from the first capacitance, the first current, the second capacitance, and the second current in S408, comprising: determining an equivalent primary voltage sequence according to the first capacitor, the second capacitor, the first current sequence and the second current sequence; and determining the spectral transfer characteristic of the capacitive voltage transformer according to the equivalent primary side voltage and the secondary side voltage in S410, including: and determining the frequency spectrum transfer characteristic of the capacitive voltage transformer according to the equivalent primary voltage sequence and the secondary side voltage sequence.
In this embodiment, the data values are all sequences acquired at intervals, the first current sensor acquires a first current sequence, the second current sensor acquires a second current sequence, and the equivalent primary side voltage sequence is determined by the first current sequence and the second current sequence, V in Is denoted as { V ] in,1 ，V in,2 ，V in,3 ...V in,k }，V in,k The primary side voltage sequences are equivalent for time k (each sequence contains the respective subharmonic spectrum). Then obtaining the equivalent primary side voltage sequenceAnd determining the frequency spectrum transfer characteristic sequence of the capacitive voltage transformer according to the acquired secondary side voltage sequence and the equivalent primary side voltage sequence.
In one embodiment, the transmission characteristic sequence G of the capacitive voltage transformer at each moment can be determined according to the equivalent primary voltage sequence and the secondary side voltage sequence and is marked as { G } 1 ，G 2 ，G 3 ...G k }。
After the frequency spectrum characteristic transfer sequence is determined, the frequency spectrum transfer characteristic of the capacitive voltage transformer is obtained by averaging the transfer characteristic sequence.
In this embodiment, the transmission characteristic sequence is obtained first, and then the transmission characteristic sequence is averaged, so that the spectrum transmission characteristic of the capacitive voltage transformer can be obtained.
The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.
The above examples illustrate only a few embodiments of the application, which are described in detail and are not to be construed as limiting the scope of the application. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the application, which are all within the scope of the application. Accordingly, the scope of protection of the present application is to be determined by the appended claims.

Claims (10)

1. A spectral transfer characteristic testing system for testing spectral transfer characteristics of a capacitive voltage transformer, the system comprising:
a load comprising a first end and a second end;
the capacitive voltage transformer comprises a high-voltage capacitor, a medium-voltage capacitor and an electromagnetic unit, wherein a first end of the high-voltage capacitor is used for being connected with a high-voltage power system, a second end of the high-voltage capacitor is connected with a first end of the medium-voltage capacitor, a second end of the medium-voltage capacitor is connected with a first grounding end, a medium-voltage end is formed between the high-voltage capacitor and the medium-voltage capacitor, a ground potential end is formed between the medium-voltage capacitor and the first grounding end, a first end of the electromagnetic unit is connected with the medium-voltage end, a second end of the electromagnetic unit is connected with the ground potential end, a third end of the electromagnetic unit is connected with a first end of a load, and a fourth end of the electromagnetic unit is connected with a second end of the load;
the first end of the harmonic source is connected with the medium voltage end, and the second end of the harmonic source is connected with the first grounding end;
a first current sensor disposed between the first ground terminal and the ground terminal; and
and the second current sensor is arranged between the second end of the medium-voltage capacitor and the ground potential end.
2. The system of claim 1, wherein a fundamental voltage of the harmonic source output spectrum is determined from a rated voltage of the medium voltage capacitor.
3. The system of claim 1, wherein the second end of the load is further connected to a second ground.
4. The system of claim 1, wherein a control switch is disposed between the harmonic source and the medium voltage terminal.
5. The system of claim 1, further comprising a harmonic analyzer, wherein the first current sensor, the second current sensor, and the load are each coupled to the harmonic analyzer, wherein the harmonic analyzer is configured to obtain a first current from the first current sensor, a second current from the second current sensor, and a secondary side voltage of the load.
6. The system of claim 5, further comprising a processor configured to:
acquiring a first capacitor of the high-voltage capacitor, acquiring a second capacitor of the medium-voltage capacitor, and acquiring rated voltage of the medium-voltage capacitor;
determining fundamental voltage of the harmonic source output frequency spectrum according to the rated voltage;
acquiring the first current, the second current, and the secondary-side voltage obtained by the harmonic analyzer in the output spectrum based on the fundamental voltage;
determining an equivalent primary-side voltage from the first capacitance, the first current, the second capacitance, and the second current;
and determining the frequency spectrum transfer characteristic of the capacitive voltage transformer according to the equivalent primary side voltage and the secondary side voltage.
7. The system of claim 5, wherein the harmonic analyzer has a recording interval, and wherein the first current, the second current, and the secondary side voltage acquired by the harmonic analyzer are all in series.
8. A method for testing spectral transfer characteristics of a capacitive voltage transformer by the system of any one of claims 1-7, the method comprising:
acquiring a first capacitor of the high-voltage capacitor, acquiring a second capacitor of the medium-voltage capacitor, and acquiring rated voltage of the medium-voltage capacitor;
determining fundamental voltage of the harmonic source output frequency spectrum according to the rated voltage;
acquiring a first current obtained by the first current sensor, a second current obtained by the second current sensor and a secondary side voltage of the load under the output frequency spectrum based on the fundamental voltage;
determining an equivalent primary-side voltage from the first capacitance, the first current, the second capacitance, and the second current;
and determining the frequency spectrum transfer characteristic of the capacitive voltage transformer according to the equivalent primary side voltage and the secondary side voltage.
9. The method of claim 8, wherein the acquiring the first current from the first current sensor, the second current from the second current sensor, and the secondary side voltage of the load at the output spectrum based on the fundamental voltage comprises:
acquiring a first current sequence obtained by the first current sensor, a second current sequence obtained by the second current sensor and a secondary side voltage sequence of the load at each moment under the output frequency spectrum based on the fundamental voltage;
said determining an equivalent primary-side voltage from said first capacitance, said first current, said second capacitance, and said second current, comprising:
determining an equivalent primary voltage sequence according to the first capacitor, the second capacitor, the first current sequence and the second current sequence;
the determining the frequency spectrum transfer characteristic of the capacitive voltage transformer according to the equivalent primary side voltage and the secondary side voltage comprises the following steps:
and determining the frequency spectrum transfer characteristic of the capacitive voltage transformer according to the equivalent primary voltage sequence and the secondary side voltage sequence.
10. The method of claim 9, wherein said determining the spectral transfer characteristics of the capacitive voltage transformer from the equivalent primary voltage sequence and the secondary side voltage sequence comprises:
determining a transfer characteristic sequence of the capacitive voltage transformer at each moment according to the equivalent primary voltage sequence and the secondary side voltage sequence;
and averaging the transfer characteristic sequences to obtain the frequency spectrum transfer characteristic of the capacitive voltage transformer.
CN202310861540.8A 2023-07-13 2023-07-13 Frequency spectrum transfer characteristic test system and test method Pending CN116908540A (en)

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