Discharge current peak moment inversion method based on electromagnetic wave signal

Abstract

The invention discloses a discharge current peak moment inversion method based on an electromagnetic wave signal, and relates to the field of pulse current characteristic inversion, and the method comprises the steps: S1, obtaining an external environment state, carrying out the analysis of the external environment state to obtain environment parameters, and constructing a partial discharge simulation model through combining the environment parameters with GIS equipment parameters; s2, acquiring electromagnetic wave signals and excitation source parameters generated by previous partial discharge, analyzing the electromagnetic wave signals to obtain characteristic parameters, and combining the characteristic parameters and the excitation source parameters to construct a partial discharge excitation source model in the partial discharge simulation model; s3, acquiring an excitation source and a probe which are required to be set at present, simulating propagation and response of partial discharge in the GIS in the partial discharge excitation source model, and recording a voltage signal waveform; s4, a peak value moment is obtained according to a time inversion algorithm in combination with the voltage signal waveform, the peak value waveform obtained through inversion is more accurate than a waveform collected by a monitoring device, and then the positioning precision of the discharge source is improved.

Description

Technical Field

[0001] The invention relates to the field of pulse current characteristic inversion, in particular to a discharge current peak moment inversion method based on electromagnetic wave signals. Background Art

[0002] The strong uncertainty, volatility and large amount of harmonics introduced in the new power system will cause power equipment to be subjected to more extreme and drastically changing operating conditions, which puts higher requirements on the safe and reliable operation of power equipment. Comprehensive, timely and accurate perception of the status of power equipment is a prerequisite for ensuring the safety of equipment, and is also a technical bottleneck for realizing the digitalization and intelligence of power equipment.

[0003] Under the current background of new power systems, the digitization and intelligence of GIS equipment are still in their early stages. The existing GIS status monitoring technology cannot fully and accurately grasp the internal status of GIS equipment. The operation and maintenance efficiency of the equipment is difficult to effectively improve, and GIS equipment failures occur frequently. Therefore, it is necessary to carry out research on holographic perception and precise evaluation technology of GIS equipment based on multi-parameter collaboration.

[0004] Inverting to obtain more information about partial discharge is of great significance for the monitoring and diagnosis of partial discharge. The peak moment of the pulse current is one of the important information about partial discharge. By inverting the peak moment of the discharge signal inside the equipment, a more accurate peak moment can be obtained than that obtained by the sensor measuring outside the equipment, thereby improving the accuracy of the discharge source locating method based on the time difference method.

[0005] Therefore, there is an urgent need for an effective method to invert the peak moment of discharge current based on electromagnetic wave signals. Summary of the invention

[0006] In order to solve the above problems, the present application provides a method for inverting the peak moment of discharge current based on electromagnetic wave signals, which further analyzes the pulse current characteristics through the pulse current peak value to achieve the effect of fault prediction.

[0007] In the present application, a method for inverting the peak moment of a discharge current based on an electromagnetic wave signal is provided, comprising the following steps: S1. Obtain the external environment state, analyze the external environment state to obtain environmental parameters, and build a partial discharge simulation model by combining the environmental parameters and GIS equipment parameters; S2, obtaining electromagnetic wave signals and excitation source parameters generated by past partial discharges, analyzing the electromagnetic wave signals to obtain characteristic parameters, and combining the characteristic parameters and excitation source parameters to construct a partial discharge excitation source model in a partial discharge simulation model; S3. Obtain current demand, set excitation source and probe according to current demand, simulate the propagation and response of partial discharge inside GIS in partial discharge excitation source model and record voltage signal waveform; S4. The peak moment is obtained according to the time inversion algorithm in combination with the voltage signal waveform, and the time difference between the pulse current peak moment and the timing start moment is obtained to locate the discharge source.

[0008] Preferably, the specific content of constructing the partial discharge simulation model in S1 in combination with the environmental parameters and the equipment parameters is: Setting environmental parameters, including: ambient temperature, ambient pressure, and ambient humidity; Obtain GIS equipment parameters, analyze them to obtain structural parameters and influencing parameters; Generate a three-dimensional simulation module for GIS equipment based on structural parameters; Configure the stereo simulation module according to the influencing parameters; The influencing parameters include characteristic parameters of insulating materials in different structures, dielectric constant, magnetic permeability parameters, air ionization characteristic parameters and breakdown strength parameters: The structural parameters include GIS equipment type, discharge gap distance and gap shape; The sensor parameters are obtained and set in the stereo simulation module, wherein the sensor parameters include position parameters, sensitivity parameters, bandwidth parameters, and directionality parameters.

[0009] Preferably, the specific content of analyzing the electromagnetic wave signal to obtain the characteristic parameters in S2 is: De-noising, filtering and normalizing the electromagnetic wave signal to improve the signal quality and obtain high-quality signal; Use the Fast Fourier Transform (FFT) method to convert high-quality signals into the frequency domain to analyze their frequencies; The peak moment, frequency component, and amplitude of high-quality signals are extracted to obtain characteristic parameters.

[0010] Preferably, the specific content of constructing the local discharge excitation source model in the local discharge simulation model by combining the characteristic parameters and the excitation source parameters in S2 is: The excitation source parameters include the excitation source type and the excitation source position, and the position calibration is performed in the partial discharge simulation model according to the excitation source position; The correspondence between the excitation source type and the characteristic parameters is obtained, and a double exponential decay function is selected based on the correspondence to construct a local discharge excitation source model.

[0011] Preferably, the specific contents of simulating the propagation and response of partial discharge inside the GIS and recording the voltage signal waveform in the partial discharge excitation source model are: Set the parameters of the current excitation source and probe. Start timing when the excitation source radiates electromagnetic waves. Record the voltage signal waveform received by the probe. ; Exchange the positions of the excitation source and the probe, invert the received voltage signal waveform in the time domain, use it as the waveform of the excitation source, perform the simulation experiment again, and record the voltage waveform received by the probe at this time .

[0012] Preferably, the specific contents of obtaining the peak moment according to the time inversion algorithm in combination with the voltage signal waveform and obtaining the time difference between the pulse current peak moment and the timing start moment and then locating the discharge source are: Voltage waveform and Convolution is performed separately to obtain ,right Waveform comparison: Calculate voltage waveform and The difference in the peak moments is the time difference between the peak value of the pulse current and the timing start moment; The discharge source is located according to the time difference between the peak value of the pulse current and the start time of timing combined with the time difference positioning method.

[0013] In summary, the method for inverting the peak moment of discharge current based on electromagnetic wave signals of the present invention is different from the traditional pulse current characteristic inversion technology. The method establishes a local discharge excitation source model, simulates the propagation and response of local discharge inside the GIS and records the voltage signal waveform, inverts the voltage signal waveform to obtain the peak moment and obtains the time difference between the pulse current peak and the timing start moment, and then locates the discharge source, which is more accurate than the waveform collected by the monitoring device, thereby helping to obtain a more accurate arrival time difference and improve the positioning accuracy of the discharge source.

[0014] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a Gaussian waveform excitation source waveform of a discharge current peak moment inversion method based on an electromagnetic wave signal of the present invention; Figure 2 It is an inversion waveform of a received signal under Gaussian pulse excitation according to a discharge current peak moment inversion method based on an electromagnetic wave signal of the present invention; Figure 3 The invention discloses a method for inverting the peak moment of a discharge current based on an electromagnetic wave signal, and convolves a received waveform after time inversion with an original received signal. DETAILED DESCRIPTION

[0016] The technical solution of the present invention is further described below by means of the accompanying drawings and embodiments. It should be noted that unless otherwise specifically stated, the relative arrangement of components and steps, numerical expressions and numerical values ​​described in these embodiments do not limit the scope of the present application.

[0017] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the present application, its application, or uses.

[0018] Technologies, systems, and devices known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, systems, and devices should be considered part of the specification.

[0019] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0020] Unless otherwise defined, technical or scientific terms used in the present invention shall have the common meanings understood by one having ordinary skills in the field to which the present invention belongs.

[0021] The present invention provides a method for inverting the peak moment of a discharge current based on an electromagnetic wave signal, which is as follows: S1. Obtain the external environment state, analyze the external environment state to obtain environmental parameters, and build a partial discharge simulation model by combining the environmental parameters and GIS equipment parameters; Preferably, the specific content of constructing the partial discharge simulation model in S1 in combination with the environmental parameters and the equipment parameters is: Setting environmental parameters, including: ambient temperature, ambient pressure, and ambient humidity; Obtain GIS equipment parameters, analyze them to obtain structural parameters and influencing parameters; Generate a three-dimensional simulation module for GIS equipment based on structural parameters; Configure the stereo simulation module according to the influencing parameters; The influencing parameters include characteristic parameters of insulating materials in different structures, dielectric constant, magnetic permeability parameters, air ionization characteristic parameters and breakdown strength parameters: The structural parameters include GIS equipment type, discharge gap distance and gap shape; The sensor parameters are obtained and set in the stereo simulation module, wherein the sensor parameters include position parameters, sensitivity parameters, bandwidth parameters, and directionality parameters.

[0022] S2, obtaining electromagnetic wave signals and excitation source parameters generated by past partial discharges, analyzing the electromagnetic wave signals to obtain characteristic parameters, and combining the characteristic parameters and excitation source parameters to construct a partial discharge excitation source model in a partial discharge simulation model; Preferably, the specific content of analyzing the electromagnetic wave signal to obtain the characteristic parameters in S2 is: De-noising, filtering and normalizing the electromagnetic wave signal to improve the signal quality and obtain high-quality signal; Use the Fast Fourier Transform (FFT) method to convert high-quality signals into the frequency domain to analyze their frequencies; The peak moment, frequency component, and amplitude of high-quality signals are extracted to obtain characteristic parameters.

[0023] Preferably, the specific content of constructing the local discharge excitation source model in the local discharge simulation model by combining the characteristic parameters and the excitation source parameters in S2 is: The excitation source parameters include the excitation source type and the excitation source position, and the position calibration is performed in the partial discharge simulation model according to the excitation source position; The correspondence between the excitation source type and the characteristic parameters is obtained, and a double exponential decay function is selected based on the correspondence to construct a local discharge excitation source model.

[0024] S3. Obtain the current demand, set the excitation source and four probes according to the current demand, simulate the propagation and response of partial discharge inside the GIS in the partial discharge excitation source model and record the voltage signal waveform; Preferably, the specific contents of simulating the propagation and response of partial discharge inside the GIS and recording the voltage signal waveform in the partial discharge excitation source model are: Set the parameters of the current excitation source and probe. Start timing when the excitation source radiates electromagnetic waves. Record the voltage signal waveform received by the probe. ; Exchange the positions of the excitation source and the probe, invert the received voltage signal waveform in the time domain, use it as the waveform of the excitation source, perform the simulation experiment again, and record the voltage waveform received by the probe at this time .

[0025] The local discharge model in the air domain is set with an origin position and a standard grid. A dipole antenna with a length equal to the standard grid size is placed at the origin as a radiation source, and another dipole antenna of the same shape is placed 40 cm away from it as a receiving antenna. A Gaussian pulse without delay is used as the excitation source waveform as shown in Figure 1 As shown, Figure 1 is the waveform of the Gaussian waveform excitation source. The signal waveform obtained by the probe is inverted as follows Figure 2 As shown: S4. The peak moment is obtained according to the time inversion algorithm in combination with the voltage signal waveform, and the time difference between the pulse current peak moment and the timing start moment is obtained to locate the discharge source.

[0026] Preferably, the specific contents of obtaining the peak moment according to the time inversion algorithm in combination with the voltage signal waveform and obtaining the time difference between the pulse current peak moment and the timing start moment and then locating the discharge source are: Voltage waveform and Convolution is performed separately to obtain ,right Waveform comparison: Calculate voltage waveform and The difference in the peak moments is the time difference between the peak value of the pulse current and the timing start moment; The discharge source is located by combining the time difference between the peak value of the pulse current and the start time of timing with the time difference positioning method. The specific positioning method is to calculate the location of the discharge source by combining the time difference and the propagation speed of the electromagnetic wave with the position of the sensor.

[0027] After the positions of the excitation source and the antenna are reversed, the reversed signal is smoothed and used as the excitation waveform input, and the comparison result of the signal received at the original excitation source and the convolution with itself is obtained as follows Figure 3 As shown, the red waveform is the signal received after time reversal, and the blue waveform is the result of convolution of the original received signal.

[0028] It can be found that the time difference between the peak-to-peak moments of the two is 0.11055us, and the peak moment of the pulse current is 0.0100143us, with an error of about 0.01%. In addition, the waveforms of the two are similar, which verifies that the essence of the time reversal method, which is to invert in the time domain and then transmit at the antenna, is to perform a conjugate transformation in the frequency domain. Whether it is a symmetrical Gaussian pulse waveform or a simulated partial discharge waveform that is more similar to the actual pulse discharge, the time reversal method can accurately obtain the peak moment of the pulse current.

[0029] Table 1 shows the actual and estimated values ​​of the peak moment of the excitation source under air conditions. It can be found that the errors between the actual and estimated values ​​in both cases are very small, both less than 1%, indicating that the method of estimating the peak moment of the pulse current based on the time reversal method is effective.

[0030] Table 1 ;

[0031] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A method for inverting the peak moment of discharge current based on electromagnetic wave signals, characterized in that: The following steps are involved: S1. Obtain the external environment state, analyze the external environment state to obtain environmental parameters, and build a partial discharge simulation model by combining the environmental parameters and GIS equipment parameters; S2, obtaining electromagnetic wave signals and excitation source parameters generated by past partial discharges, analyzing the electromagnetic wave signals to obtain characteristic parameters, and combining the characteristic parameters and excitation source parameters to construct a partial discharge excitation source model in a partial discharge simulation model; S3. Obtain current demand, set excitation source and probe according to current demand, simulate the propagation and response of partial discharge inside GIS in partial discharge excitation source model and record voltage signal waveform; S4. The peak moment is obtained according to the time inversion algorithm in combination with the voltage signal waveform, and the time difference between the pulse current peak moment and the timing start moment is obtained to locate the discharge source.

2. The method for inverting the peak moment of discharge current based on electromagnetic wave signals according to claim 1, characterized in that: The specific contents of the partial discharge simulation model constructed by combining environmental parameters and equipment parameters in S1 are as follows: Setting environmental parameters, including: ambient temperature, ambient pressure, and ambient humidity; Obtain GIS equipment parameters, analyze them to obtain structural parameters and influencing parameters; Generate a three-dimensional simulation module for GIS equipment based on structural parameters; Configure the stereo simulation module according to the influencing parameters; The influencing parameters include characteristic parameters of insulating materials in different structures, dielectric constant, magnetic permeability parameters, air ionization characteristic parameters and breakdown strength parameters: The structural parameters include GIS equipment type, discharge gap distance and gap shape; The sensor parameters are obtained and set in the stereo simulation module, wherein the sensor parameters include position parameters, sensitivity parameters, bandwidth parameters, and directionality parameters.

3. The method for inverting the peak moment of discharge current based on electromagnetic wave signals according to claim 1, characterized in that: The specific content of the characteristic parameters obtained by analyzing the electromagnetic wave signal in S2 is: De-noising, filtering and normalizing the electromagnetic wave signal to improve the signal quality and obtain high-quality signal; Use the Fast Fourier Transform (FFT) method to convert high-quality signals into the frequency domain to analyze their frequencies; The peak moment, frequency component, and amplitude of high-quality signals are extracted to obtain characteristic parameters.

4. The method for inverting the peak moment of discharge current based on electromagnetic wave signals according to claim 3, characterized in that: The specific contents of constructing the local discharge excitation source model in the local discharge simulation model by combining the characteristic parameters and the excitation source parameters in S2 are as follows: The excitation source parameters include the excitation source type and the excitation source position, and the position calibration is performed in the partial discharge simulation model according to the excitation source position; The correspondence between the excitation source type and the characteristic parameters is obtained, and a double exponential decay function is selected based on the correspondence to construct a local discharge excitation source model.

5. The method for inverting the peak moment of discharge current based on electromagnetic wave signals according to claim 4, characterized in that: The specific contents of simulating the propagation and response of partial discharge inside GIS and recording the voltage signal waveform in the partial discharge excitation source model are as follows: Set the parameters of the current excitation source and probe. Start timing when the excitation source radiates electromagnetic waves. Record the voltage signal waveform received by the probe. ; Exchange the positions of the excitation source and the probe, invert the received voltage signal waveform in the time domain, use it as the waveform of the excitation source, perform the simulation experiment again, and record the voltage waveform received by the probe at this time .

6. The method for inverting the peak moment of discharge current based on electromagnetic wave signals according to claim 5, characterized in that: The specific contents of locating the discharge source by combining the voltage signal waveform with the time inversion algorithm to obtain the peak time and the time difference between the pulse current peak and the timing start time are as follows: Voltage waveform and Convolution is performed separately to obtain ,right Waveform comparison: Calculate voltage waveform and The difference in the peak moments is the time difference between the peak value of the pulse current and the timing start moment; The discharge source is located according to the time difference between the peak value of the pulse current and the start time of timing combined with the time difference positioning method.

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