High-frequency current sensor sensitivity verification method considering narrow-band interference

Abstract

The invention discloses a high-frequency current sensor sensitivity verification method considering narrowband interference. The method comprises the following key steps of: performing a sensitivity test on a high-frequency current sensor to obtain a signal with a specific frequency, inputting the signal into the high-frequency current sensor, and calculating an interference compensation coefficient and the sensitivity of the high-frequency sensor. The method effectively verifies the performance of the sensor in an actual working environment, and ensures that the sensor can still maintain high sensitivity and accuracy when facing narrow-band interference, thereby improving the reliability of monitoring data and the stability of the whole system.

Description

Technical Field

[0001] The present invention relates to a sensitivity calibration method for a high-frequency current sensor, in particular to a sensitivity calibration method for a high-frequency current sensor taking narrowband interference into account. The technology is used to effectively calibrate the sensitivity of a high-frequency current sensor in a complex electromagnetic environment. Background Art

[0002] In modern power systems, real-time monitoring of the health of electrical equipment is the key to ensuring safe and reliable operation of the system. High-frequency current sensors have become an important tool for monitoring partial discharge signals due to their high sensitivity and good frequency response characteristics.

[0003] Various electromagnetic interferences are common in the actual power system operating environment, especially narrowband interferences, which may come from other electronic devices, communication signals or power lines themselves. The presence of narrowband interference will affect the performance of high-frequency current sensors, reduce their detection sensitivity and accuracy for partial discharge signals, and thus affect the results of fault diagnosis. Traditional verification methods often ignore the impact of narrowband interference or lack effective interference compensation mechanisms, resulting in verification results that cannot truly reflect the performance of the sensor under actual working conditions. Therefore, it is particularly important to develop a high-frequency current sensor sensitivity verification method that can take narrowband interference into account.

[0004] The present invention provides a novel calibration method, which aims to solve the limitations of the prior art. The method comprehensively considers the narrowband interference in the field environment, adopts advanced signal processing technology and interference compensation algorithm, and accurately calibrates the sensitivity of the high-frequency current sensor. Through this method, the performance of the sensor can be effectively evaluated and adjusted to ensure that it can still accurately detect partial discharge signals in the face of narrowband interference, providing a solid technical guarantee for the stable operation of the power system. Summary of the invention

[0005] The purpose of the present invention is to provide a high-frequency current sensor sensitivity calibration method taking into account narrowband interference, taking into account narrowband interference in a complex on-site electromagnetic environment, and improving the accuracy of high-frequency current sensor sensitivity calibration.

[0006] The technical solution of the present invention is:

[0007] Step 1: Generate and output an excitation signal D with a frequency of f0 and an amplitude of D through a signal generator. in (f0), and input the signal into the high-frequency current sensor; the secondary side of the high-frequency current sensor is connected to the host computer, and the host computer is used to measure the output signal U of the high-frequency current sensor at the frequency f0 out (f); The signal generator is connected in series with a standard resistor R, and the voltage U across the resistor is measured using an oscilloscopeR .

[0008] Step 2: Considering the narrowband interference in the field verification environment, the response H(f) of the high-frequency current sensor to the excitation signal U(f0) is calculated using the following formula:

[0009] U out (f)=|H(f)|·D in (f0)·δ(f-f0)+|H(f-f1)|·J(f1)·δ(f-f1)

[0010] Among them, δ(f) is the Dirac function, J(f1) is the frequency domain model of narrowband interference,

[0011]

[0012] Where A is the narrowband interference amplitude, B is the bandwidth of the narrowband interference, f1 is the interference center frequency, and u is the step function;

[0013] Step 3: Calculate the interference compensation coefficient C as follows:

[0014]

[0015] Where R is the outer diameter of the high-frequency current sensor coil, r is the inner diameter of the coil, and σ is the eccentricity of the coil.

[0016] Step 4: Calculate the sensitivity of the high-frequency sensor using the following formula:

[0017]

[0018] Step 5: Change the output signal frequency of the signal generator within the range of 3 to 30 MHz, repeat the above steps, average the multiple sensitivity values ​​λ obtained, and obtain the average sensitivity of the high-frequency current sensor to be calibrated within the frequency range.

[0019] Compared with the prior art, the advantages of the present invention are:

[0020] 1. The present invention particularly considers the possible narrowband interference in the field environment and calculates the interference compensation coefficient. This step is often ignored in the prior art. The present invention significantly improves the verification accuracy in an interference environment through this compensation mechanism.

[0021] 2. In step 5, the present invention covers a wide frequency range of 3 to 30 MHz by changing the output frequency of the signal generator, which makes the calibration result representative and accurate in a wider frequency range, rather than limited to the calibration of a single frequency point;

[0022] 3. By repeating the calibration steps at multiple frequency points and obtaining the mean sensitivity by taking the arithmetic mean, the present invention provides a more comprehensive and reliable sensitivity evaluation and reduces the influence of accidental errors. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a flow chart of the method for calibrating the sensitivity of a high-frequency current sensor;

[0024] Figure 2 It is a schematic diagram of a narrowband interference signal with a center frequency of 2MHz and a bandwidth of 1M;

[0025] Figure 3 It is the structural diagram of the high-frequency current sensor sensitivity calibration system;

[0026] Figure 4 This is the structural diagram of a high-frequency current sensor based on a Rogowski coil. DETAILED DESCRIPTION

[0027] The present invention is further described below in conjunction with the accompanying drawings and specific implementation processes. It should be emphasized that the specific implementation cases described herein are only used to explain the present invention patent and are not used to limit the scope of the present invention patent concept and its claims. In addition, the technical features involved in the different implementations of the present application described below can be combined with each other as long as they do not conflict with each other.

[0028] refer to Figures 1 to 4 , Figure 1 It is a flow chart of the method for calibrating the sensitivity of a high-frequency current sensor; Figure 2 It is a schematic diagram of a narrowband interference signal with a center frequency of 2MHz and a bandwidth of 1M; Figure 3 It is the structural diagram of the high-frequency current sensor sensitivity calibration system; Figure 4 This is the structural diagram of a high-frequency current sensor based on a Rogowski coil.

[0029] exist Figure 1 In the embodiment of the present application, a method for calibrating the sensitivity of a high-frequency current sensor taking into account narrowband interference is provided, comprising the following steps:

[0030] Step 1: Generate and output an excitation signal D with a frequency of f0 and an amplitude of D through a signal generator. in (f0), and input the signal into the high-frequency current sensor; the secondary side of the high-frequency current sensor is connected to the host computer, and the host computer is used to measure the output signal U of the high-frequency current sensor at the frequency f0 out (f); The signal generator is connected in series with a standard resistor R, and the voltage U across the resistor is measured using an oscilloscope R .

[0031] Step 2: Considering the narrowband interference in the field verification environment, the response H(f) of the high-frequency current sensor to the excitation signal U(f0) is calculated using the following formula:

[0032] U out (f)=|H(f)|·D in (f0)·δ(f-f0)+|H(f-f1)|·J(f1)·δ(f-f1)

[0033] Among them, δ(f) is the Dirac function and J(f1) is the frequency domain model of narrowband interference:

[0034]

[0035] In the formula, A is the narrowband interference amplitude, B is the bandwidth of the narrowband interference, f1 is the interference center frequency, and u is the step function. Figure 2 In the embodiment of the present application, a schematic diagram of a narrowband interference signal with a center frequency of 2 MHz and a bandwidth of 1 M is provided.

[0036] Step 3: Calculate the interference compensation coefficient C as follows:

[0037]

[0038] In the formula, R is the outer diameter of the high-frequency current sensor coil, r is the inner diameter of the coil, and σ is the eccentricity of the coil. Figure 4 In the embodiment of the present application, a structural diagram of a high-frequency current sensor based on a Rogowski coil is provided.

[0039] Step 4: Calculate the sensitivity of the high-frequency sensor using the following formula:

[0040]

[0041] Step 5: Change the output signal frequency of the signal generator within the range of 3 to 30 MHz, repeat the above steps, average the multiple sensitivity values ​​λ obtained, and obtain the average sensitivity of the high-frequency current sensor to be calibrated within the frequency range.

Claims

1. A method for calibrating the sensitivity of a high-frequency current sensor taking narrowband interference into account, characterized in that: A sensitivity calibration test is performed on a high-frequency current sensor in the presence of narrowband interference in a field environment. The method includes the following steps: Step 1: Generate and output an excitation signal D with a frequency of f0 and an amplitude of D through a signal generator. in (f0), and input the signal into a high frequency current sensor; The secondary side of the high-frequency current sensor is connected to the host computer, and the host computer is used to measure the output signal U of the high-frequency current sensor at the frequency f0. out (f); The signal generator is connected in series with a standard resistor R, and an oscilloscope is used to measure the voltage U across the resistor. R ; Step 2: Considering the narrowband interference in the field verification environment, use the following formula to calculate the high-frequency current sensor's response to the excitation signal D in The response H(f) of (f0): U out (f)=|H(f)|·D in (f0)·δ(f-f0)+|H(f-f1)|·J(f1)·δ(f-f1); Among them, δ(f) is the Dirac function and J(f1) is the frequency domain model of narrowband interference: Where A is the narrowband interference amplitude, B is the bandwidth of the narrowband interference, f1 is the interference center frequency, and u is the step function; Step 3: Calculate the interference compensation coefficient C as follows: In the formula, R is the outer diameter of the high-frequency current sensor coil, r is the inner diameter of the coil, and σ is the eccentricity of the coil; Step 4: Calculate the sensitivity of the high-frequency sensor using the following formula:

2. The high-frequency current sensor sensitivity calibration method according to claim 1, characterized in that: The excitation signal D in The frequency range of (f0) is 3MHz-30MHz; The spectrum of narrowband interference signals is mainly distributed below 10MHz; The sensor to be tested is a clamp-type high-frequency current sensor based on a Rogowski coil, which is used to monitor partial discharge of a main substation equipment.

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