CN119471524A - A method for calibrating the sensitivity of high-frequency current sensors taking narrowband interference into account - Google Patents
A method for calibrating the sensitivity of high-frequency current sensors taking narrowband interference into account Download PDFInfo
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- CN119471524A CN119471524A CN202411559350.1A CN202411559350A CN119471524A CN 119471524 A CN119471524 A CN 119471524A CN 202411559350 A CN202411559350 A CN 202411559350A CN 119471524 A CN119471524 A CN 119471524A
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- 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
- G01R35/005—Calibrating; Standards or reference devices, e.g. voltage or resistance standards, "golden" references
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/12—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/12—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing
- G01R31/1227—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials
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- G06—COMPUTING OR CALCULATING; COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
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Abstract
The invention discloses a high-frequency current sensor sensitivity verification method considering narrowband interference, which comprises the following key steps: A sensitivity test is carried out on the high-frequency current sensor, signals with specific frequencies are obtained and input into the high-frequency current sensor, and an interference compensation coefficient and the sensitivity of the high-frequency sensor are calculated. The method effectively verifies the performance of the sensor in the actual working environment, and ensures that the sensor can still keep high sensitivity and accuracy when facing narrowband interference, thereby improving the reliability of monitoring data and the stability of the whole system.
Description
Technical Field
The invention relates to a high-frequency current sensor sensitivity calibration method, in particular to a high-frequency current sensor sensitivity calibration method considering narrow-band interference.
Background
In modern power systems, real-time monitoring of the health status of electrical equipment is critical to ensure safe and reliable operation of the system. High frequency current sensors are an important tool for monitoring partial discharge signals due to their high sensitivity and good frequency response characteristics.
Various electromagnetic interferences, in particular narrowband interferences, are prevalent in the practical power system operating environment, which may originate from other electronic devices, communication signals or the power line itself. The existence of the narrow-band interference can influence the performance of the high-frequency current sensor, reduce the detection sensitivity and accuracy of the high-frequency current sensor to the local discharge signal, and influence the fault diagnosis result. The traditional verification method often neglects the influence of narrow-band interference or lacks an effective interference compensation mechanism, so that the verification result cannot truly reflect the performance of the sensor under the actual working condition. Therefore, it is important to develop a high-frequency current sensor sensitivity verification method capable of considering narrowband interference.
The invention provides a novel verification method, and aims to solve the limitation in the prior art. The method adopts advanced signal processing technology and interference compensation algorithm to accurately check the sensitivity of the high-frequency current sensor by comprehensively considering the narrow-band interference in the field environment. By the method, the performance of the sensor can be effectively evaluated and adjusted, partial discharge signals can be accurately detected when the sensor faces narrow-band interference, and a solid technical guarantee is provided for the stable operation of the power system.
Disclosure of Invention
The invention aims to provide a high-frequency current sensor sensitivity verification method considering narrow-band interference, which considers the narrow-band interference in a complex electromagnetic environment on site and improves the accuracy of high-frequency current sensor sensitivity verification.
The technical scheme of the invention is as follows:
Step one, generating and outputting an excitation signal D in(f0 with frequency f 0 and amplitude D through a signal generator, inputting the excitation signal D in(f0 into a high-frequency current sensor, connecting the secondary side of the high-frequency current sensor with an upper computer, measuring an output signal U out (f) of the high-frequency current sensor at frequency f 0 through the upper computer, connecting the signal generator in series with a standard resistor R, and measuring voltages U R at two ends of the resistor through an oscilloscope.
Step two, considering the narrow-band interference existing in the field verification environment, calculating the response H (f) of the high-frequency current sensor to the excitation signal U (f 0) by using the following formula,
Uout(f)＝|H(f)|·Din(f0)·δ(f-f0)+|H(f-f1)|·J(f1)·δ(f-f1)
Wherein delta (f) is a dirac function, J (f 1) is a frequency domain model of narrowband interference,
Wherein A is the narrow-band interference amplitude, B is the bandwidth of narrow-band interference, f 1 is the interference center frequency, and u is a step function;
Step three, calculating an interference compensation coefficient C, wherein the following formula is as follows:
Wherein R is the outer diameter of the coil of the high-frequency current sensor, R is the inner diameter of the coil, and sigma is the eccentricity of the coil.
Step four, calculating the sensitivity of the high-frequency sensor by using the following formula:
And fifthly, changing the frequency of the output signal of the signal generator within the range of 3-30 MHz, repeating the steps, and averaging a plurality of obtained sensitivity values lambda to obtain the average sensitivity of the high-frequency current sensor to be checked within the frequency range.
Compared with the prior art, the invention has the advantages that:
1. the invention considers the possible narrow-band interference in the field environment, and calculates the interference compensation coefficient, which is ignored in the prior art, and the invention improves the checking accuracy in the interference environment obviously through the compensation mechanism;
2. In the fifth step, the output frequency of the signal generator is changed to cover a wide frequency range of 3-30 MHz, so that the verification result has representativeness and accuracy in a wider frequency range and is not limited to verification of a single frequency point;
3. by repeating the calibration step at a plurality of frequency points and calculating the mean sensitivity obtained by the arithmetic mean, the invention provides a more comprehensive and reliable sensitivity assessment, reducing the effect of accidental errors.
Drawings
FIG. 1 is a flow chart of a high frequency current sensor sensitivity verification method;
FIG. 2 is a schematic diagram of a narrowband interfering signal having a center frequency of 2MHz and a bandwidth of 1M;
FIG. 3 is a block diagram of a high frequency current sensor sensitivity verification system;
fig. 4 is a structural diagram of a rogowski coil-based high-frequency current sensor.
Detailed Description
The application will be further described with reference to the drawings and detailed description. It should be emphasized that the embodiments described herein are merely illustrative of the present application, and are not intended to limit the scope of the inventive concepts and the claims. In addition, the technical features described below in the different embodiments of the present application may be combined with each other as long as they do not collide with each other.
Referring to fig. 1 to 4, fig. 1 is a flowchart of a high-frequency current sensor sensitivity checking method, fig. 2 is a schematic diagram of a narrow-band interference signal with a center frequency of 2MHz and a bandwidth of 1M, fig. 3 is a structural diagram of a high-frequency current sensor sensitivity checking system, and fig. 4 is a structural diagram of a high-frequency current sensor based on rogowski coils.
In fig. 1, an embodiment of the present application provides a method for checking sensitivity of a high-frequency current sensor, which includes the following steps:
Step one, generating and outputting an excitation signal D in(f0 with frequency f 0 and amplitude D through a signal generator, inputting the excitation signal D in(f0 into a high-frequency current sensor, connecting the secondary side of the high-frequency current sensor with an upper computer, measuring an output signal U out (f) of the high-frequency current sensor at frequency f 0 through the upper computer, connecting the signal generator in series with a standard resistor R, and measuring voltages U R at two ends of the resistor through an oscilloscope.
Step two, considering the narrow-band interference existing in the field verification environment, calculating the response H (f) of the high-frequency current sensor to the excitation signal U (f 0) by using the following formula:
Uout(f)＝|H(f)|·Din(f0)·δ(f-f0)+|H(f-f1)|·J(f1)·δ(f-f1)
Wherein δ (f) is a dirac function and J (f 1) is a frequency domain model of narrowband interference:
Wherein A is the narrow-band interference amplitude, B is the bandwidth of the narrow-band interference, f 1 is the interference center frequency, and u is a step function. In fig. 2, an embodiment of the present application provides a schematic diagram of a narrowband interference signal with a center frequency of 2MHz and a bandwidth of 1M.
Step three, calculating an interference compensation coefficient C, wherein the following formula is as follows:
Wherein R is the outer diameter of the coil of the high-frequency current sensor, R is the inner diameter of the coil, and sigma is the eccentricity of the coil. In fig. 4, an embodiment of the present application provides a structural diagram of a rogowski coil-based high frequency current sensor.
Step four, calculating the sensitivity of the high-frequency sensor by using the following formula:
And fifthly, changing the frequency of the output signal of the signal generator within the range of 3-30 MHz, repeating the steps, and averaging a plurality of obtained sensitivity values lambda to obtain the average sensitivity of the high-frequency current sensor to be checked within the frequency range.
Claims (2)
1. A high-frequency current sensor sensitivity verification method considering narrow-band interference is characterized in that a sensitivity verification test is carried out on a high-frequency current sensor under the condition that the narrow-band interference exists in a field environment, and the method comprises the following steps:
Step one, generating and outputting an excitation signal D in(f0 with frequency f 0 and amplitude D through a signal generator, and inputting the signal into a high-frequency current sensor;
The secondary side of the high-frequency current sensor is connected with an upper computer, and the upper computer is used for measuring an output signal U out (f) of the high-frequency current sensor at the frequency f 0;
The signal generator is connected in series with the standard resistor R, and the voltage U R at two ends of the resistor is measured by an oscilloscope;
step two, considering the narrow-band interference existing in the field verification environment, calculating the response H (f) of the high-frequency current sensor to the excitation signal D in(f0) by using the following formula:
Uout(f)＝|H(f)|·Din(f0)·δ(f-f0)+|H(f-f1)|·J(f1)·δ(f-f1);
Wherein δ (f) is a dirac function and J (f 1) is a frequency domain model of narrowband interference:
Wherein A is the narrow-band interference amplitude, B is the bandwidth of narrow-band interference, f 1 is the interference center frequency, and u is a step function;
Step three, calculating an interference compensation coefficient C, wherein the following formula is as follows:
Wherein R is the outer diameter of a coil of the high-frequency current sensor, R is the inner diameter of the coil, and sigma is the eccentricity of the coil;
Step four, calculating the sensitivity of the high-frequency sensor by using the following formula:
2. the method for verifying sensitivity of a high-frequency current sensor according to claim 1, wherein the frequency range of the excitation signal D in(f0) is 3MHz to 30MHz;
the frequency spectrum of the narrow-band interference signal is mainly distributed below 10 MHz;
The sensor to be checked is a clamp type high-frequency current sensor based on a rogowski coil and is used for monitoring partial discharge of power transformation main equipment.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202411559350.1A CN119471524A (en) | 2024-11-04 | 2024-11-04 | A method for calibrating the sensitivity of high-frequency current sensors taking narrowband interference into account |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202411559350.1A CN119471524A (en) | 2024-11-04 | 2024-11-04 | A method for calibrating the sensitivity of high-frequency current sensors taking narrowband interference into account |
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| CN119471524A true CN119471524A (en) | 2025-02-18 |
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