Pumped storage unit GCB aging state evaluation method and system

Abstract

The present application relates to the field of GCB state monitoring, in order to improve the accuracy and reliability of GCB aging state evaluation, provide pumped storage unit GCB aging state evaluation method and system, based on singular value decomposition to the original vibration signal denoising obtains only the signal containing white noise, then adopt correlation scale transformation method removes white noise, realize in the decomposition of the effective signal of the contact state in the multi-source vibration signal;Based on the signal after removing white noise, the mean, standard deviation, root mean square value, skewness and waveform factor are calculated, and then the aging state correction factor is determined, the life model is corrected, thereby the accuracy and reliability of GCB aging state evaluation are improved.

Description

Technical Field

[0001] This invention relates to the field of GCB condition monitoring, specifically a method and system for assessing the aging condition of a pumped storage unit's GCB. Background Technology

[0002] As a critical piece of equipment in pumped-storage power stations, the reliability of the GCB (Generator Outlet Circuit Breaker) directly impacts the stable operation of the hydropower system. Due to their complex operating conditions, pumped-storage units frequently switch between multiple modes, including power generation, pumping, phase regulation, and shutdown. During operation, the GCB experiences both mechanical and electrical losses, leading to GCB aging, performance degradation, increased failure risk, and threats to power continuity. Furthermore, GCB aging can cause insulation degradation and mechanical component failure, increasing the risk of short circuits, explosions, and other safety accidents. From an economic perspective, unplanned GCB outages and maintenance due to malfunctions result in losses in manpower and equipment costs. Therefore, aging assessment of the GCB is essential for ensuring the normal operation of pumped-storage power stations.

[0003] Vibration signal method is a non-invasive measurement method. Extracting contact erosion characteristics from vibration signals can enable the assessment of the mechanical condition of circuit breaker contacts. However, the current method for assessing mechanical life using vibration signals is challenging because multiple components of the circuit breaker generate vibration signals during operation, with the vibration signal during contact collision being the most critical. Decomposing effective signal characteristics representing the contact condition from multi-source vibration signals is crucial. Furthermore, the variation law of vibration signals caused by contact erosion is unclear, resulting in low discriminative power of the erosion characteristics extracted from the vibration signals. In addition, due to the high start-stop frequency of the generator / motor circuit breaker (GCB) in pumped storage units, the applicability of conventional circuit breaker aging assessment models is significantly limited under this operating condition. Summary of the Invention

[0004] To improve the accuracy and reliability of GCB aging status assessment, this application provides a method and system for assessing the aging status of pumped storage units' GCBs.

[0005] The technical solution adopted by the present invention to solve the above problems is:

[0006] The aging status assessment method for pumped storage units (GCBs) includes:

[0007] Step 1: Collect vibration signals;

[0008] Step 2: Denoise the acquired vibration signal based on singular value decomposition, and then remove white noise using the correlation scaling method;

[0009] Step 3: Obtain feature parameters based on the signal after removing white noise, including: mean. Standard deviation Root mean square value skewness and waveform factor ;

[0010] Step 4: Calculate the GCB aging status correction factor for the pumped storage unit based on the characteristic parameters. : ;

[0011] Step 5: Assess the aging status of the GCB based on the aging status correction factor.

[0012] Furthermore, the steps for denoising vibration signals based on singular value decomposition are as follows:

[0013] Step 211: Perform a Fourier transform on the original vibration signal to obtain the spectrum. ;

[0014] Step 212: Perform a differential transform on the spectrum to obtain... ;

[0015] Step 213: Set the threshold : , Let N be the standard deviation of the vibration signal, and N be the total number of sampling points.

[0016] Step 214, Medium to large The number of data points is denoted as ;

[0017] Step 215: Construct the Hankel matrix H based on the original vibration signal:

[0018] ,

[0019] In the formula, H is the Hankel matrix; This represents the value of the nth sampling point in the noisy vibration signal; the m rows indicate that the signal is divided into m consecutive and overlapping time segments. If the vibration signal is decomposed using singular values, the first... If a singular value is greater than A times the subsequent value, then m takes... +1;

[0020] Step 216: Perform singular value decomposition on matrix H to obtain... orthogonal matrix U, The orthogonal matrix V and the non-negative diagonal matrix S;

[0021] Step 217, move the front of S Each element is set to 0 to construct a new diagonal matrix. The matrix is ​​obtained by reconstructing using singular values. Based on matrix Obtain the noise-reduced vibration signal .

[0022] Furthermore, let A be 10.

[0023] Furthermore, the specific steps for removing white noise using the relevant scaling method are as follows:

[0024] Step 221: Perform wavelet transform on the vibration signal containing white noise to obtain... , This represents the noisy signal at position n on scale j. Discrete wavelet transform;

[0025] Step 222: Calculate the correlation coefficient , ;

[0026] Step 223: Calculate the normalized correlation value , , , ;

[0027] Step 224: Compare normalized correlation values and wavelet transform values The reconstructed wavelet transform values ​​are obtained. :

[0028] like Then The value assigned The corresponding position;

[0029] like ,but The corresponding position is assigned a value of 0;

[0030] Step 225, As a new Repeat steps 222 to 224, with the loop terminating under the following condition: The corresponding wavelet transform energy is less than the threshold of noise energy;

[0031] Step 226, for the obtained Wavelet transform is performed to obtain the signal after removing white noise.

[0032] Furthermore, step 5 specifically involves: remaining lifespan. , , , To allow for a certain number of disconnections, For relative electrical wear during a single interruption, The relative electrical wear is denoted by z switching cycles.

[0033] The pumped storage unit GCB aging status assessment system includes:

[0034] Data acquisition unit: used to acquire vibration signals;

[0035] Denoising unit: The acquired vibration signal is denoised based on singular value decomposition, and then white noise is removed by correlation scaling method;

[0036] Feature parameter acquisition unit: Acquires feature parameters based on the signal after removing white noise, including: mean. Standard deviation Root mean square value skewness and waveform factor ;

[0037] Aging Condition Correction Factor Calculation Unit: Calculates the aging condition correction factor of the pumped storage unit's GCB based on characteristic parameters. : ;

[0038] Aging Status Assessment Unit: Assess the aging status of the GCB based on the aging status correction factor.

[0039] Furthermore, the data acquisition unit includes an acceleration vibration sensor, a constant current source adapter, and a data acquisition card.

[0040] The advantages of this invention compared to existing technologies are as follows: The original vibration signal is denoised using singular value decomposition to obtain a signal containing only white noise. Then, the white noise is removed using a correlation scaling method, thus decomposing an effective signal representing the contact state from a multi-source vibration signal. Based on the signal after removing white noise, the mean, standard deviation, root mean square value, skewness, and waveform factor are calculated to determine the aging state correction factor, thereby correcting the life model and improving the accuracy and reliability of GCB aging state assessment. Attached Figure Description

[0041] Figure 1 Flowchart for the GCB aging status assessment method of pumped storage units. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0043] like Figure 1 As shown, the method for assessing the aging status of pumped storage units (GCBs) includes:

[0044] Step 1: Collect vibration signals.

[0045] The device platform for collecting vibration signals includes an acceleration vibration sensor, a constant current source adapter, a data acquisition card, and a host computer. The magnetically fixed acceleration vibration sensor is installed on the crossbeam of the high-voltage circuit breaker. The envelope of the signal collected at this location is obvious, which conforms to the principle of sensor installation location selection. The signal collected by the acceleration sensor is transmitted to the host computer through the data acquisition card after passing through the constant current source adapter.

[0046] Step 2: Denoise the acquired vibration signal based on singular value decomposition, and then remove white noise using the correlation scaling method. Specifically, this includes:

[0047] 1) For the original vibration signal Perform a Fourier transform to obtain the spectrum. ;

[0048] 2) Perform differential transform on the spectrum: In the formula, N is the total number of sampling points for the vibration signal containing noise.

[0049] 3) Set threshold : ,

[0050] In the formula, Let the standard deviation of the vibration signal be denoted as . Medium to large The number of data points is denoted as The format of periodic narrowband interference in the signal is as follows: Here, N=2000 is chosen, and the threshold is obtained through simulation calculation. By comparing thresholds, we can obtain .

[0051] 4) Constructing noisy vibration signals Hankel matrix H:

[0052] ,

[0053] In the formula, H is the Hankel matrix; This represents the value of the nth sampling point in the noisy vibration signal; the m rows indicate that the signal is divided into m consecutive and overlapping time segments. If the vibration signal is decomposed using singular values, the first... If a singular value is significantly larger than subsequent values, such as more than 10 times, then m must be at least 1 / 2. +1 is added to retain the main components of periodic narrowband interference. In this embodiment, m = N / 2 + 1 and n = N / 2 are set so that the Hankel matrix retains all information.

[0054] By constructing the Hankel matrix and performing linear rearrangement, the inherent structure of the signal on the time axis (periodicity, correlation) is transformed into the algebraic characteristics of the matrix (rank, singular value distribution), thus enabling subsequent SVD decomposition to achieve signal separation based on "regularity" rather than "frequency".

[0055] 5) Perform the following on the Hankel matrix H Decomposition yields an m×m orthogonal matrix U and an n×n orthogonal matrix V, as well as a non-negative diagonal matrix S, which is a singular value matrix.

[0056] 6) Because it exceeds the threshold Set the first 20 elements of S to 0 to construct a new diagonal matrix. Singular value reconstruction can be used to obtain the Hankel matrix after removing periodic narrowband interference. This will give you the signal after singular value denoising. At this time, the vibration signal It contains only white noise.

[0057] To remove white noise from the vibration signal, this embodiment employs a correlation scaling method, specifically including:

[0058] 1) Perform wavelet transform on the vibration signal containing white noise in MATLAB to obtain... , This represents the noisy signal at position n on scale j. Discrete wavelet transform;

[0059] 2) Calculate the correlation coefficient using the transformed values ​​from adjacent scales. : Where l is the number of scales involved in the calculation, typically l=2. Therefore, the above formula can be simplified to: .

[0060] 3) Calculate the normalized correlation value ,

[0061] , , ;

[0062] 4) Compare normalized correlation values and wavelet transform values The reconstructed wavelet transform values ​​are obtained. :

[0063] like Then it is assumed that the wavelet transform at point n is generated by the vibration signal itself, and... The value assigned The corresponding position;

[0064] like Therefore, it is assumed that the wavelet transform at point n is generated by white noise. The corresponding position is assigned a value of 0;

[0065] 5) As a new And repeat steps 2) through 4), the loop terminates under the condition that: Corresponding wavelet transform energy The threshold value is less than the noise energy threshold; in this embodiment, it is set to 10. ;

[0066] 6) To The white noise-free signal is obtained by performing wavelet transform in MATLAB.

[0067] Step 3: Obtain feature parameters based on the signal after removing white noise, including: mean. Standard deviation Root mean square value skewness and waveform factor ;

[0068] , , , , .

[0069] The mean reflects the DC component of the vibration signal, and its long-term monotonic trend can serve as a sensitive indicator of structural aging or permanent deformation. The standard deviation describes the intensity of the signal fluctuation around the mean, directly related to the energy dispersion of the system's dynamic response, and its growth trend is often strongly correlated with degradation mechanisms such as fatigue accumulation, increased wear, or loosening. The root mean square value characterizes the overall intensity of the vibration signal from an energy equivalence perspective, and its growth trend conforms to the basic assumptions of fatigue models such as Paris's law. The skewness measures the asymmetry of the signal probability distribution, and its abrupt changes or upward trends can serve as indicators of the initiation and expansion of local damage. The waveform factor reflects the sharpening or flattening evolution of the vibration waveform, which can indicate the transformation or coupling of fault modes and improve the identification accuracy of the life staging model.

[0070] Step 4: Calculate the GCB aging status correction factor for the pumped storage unit based on the characteristic parameters. : .

[0071] This application derives a formula for calculating the aging state correction factor based on a large amount of experimental data. This formula can effectively combine the characteristics of the above-mentioned feature parameters, thereby effectively evaluating the aging of GCB.

[0072] Step 5: Assess the aging status of the GCB based on the aging status correction factor.

[0073] According to the information provided by GCB at the time of its appearance — Curve, to obtain arbitrary on / off energy Corresponding number of interruptions Therefore, the corresponding single-break energy is obtained as The relative electrical wear at that time is , Then, the relative electrical wear of z switching operations is calculated. , The remaining lifetime L is: .

Claims

1. A method for assessing the aging status of a pumped storage unit's GCB (Gas Collector Block) system, characterized in that... include: Step 1: Collect vibration signals; Step 2: Denoise the acquired vibration signal based on singular value decomposition, and then remove white noise using the correlation scaling method; Step 3: Obtain feature parameters based on the signal after removing white noise, including: mean. Standard deviation Root mean square value skewness and waveform factor ; Step 4: Calculate the GCB aging status correction factor for the pumped storage unit based on the characteristic parameters. : ; Step 5: Assess the aging status of the GCB based on the aging status correction factor.

2. The method for assessing the aging status of a pumped storage unit's GCB according to claim 1, characterized in that, The steps for denoising vibration signals based on singular value decomposition are as follows: Step 211: Perform a Fourier transform on the original vibration signal to obtain the spectrum. ; Step 212: Perform a differential transform on the spectrum to obtain... ; Step 213: Set the threshold : , Let N be the standard deviation of the vibration signal, and N be the total number of sampling points. Step 214, Medium to large The number of data points is denoted as ; Step 215: Construct the Hankel matrix H based on the original vibration signal: ， In the formula, H is the Hankel matrix; This represents the value of the nth sampling point in the noisy vibration signal; the m rows indicate that the signal is divided into m consecutive and overlapping time segments. If the vibration signal is decomposed using singular values, the first... If a singular value is greater than A times the subsequent value, then m takes... +1; Step 216: Perform singular value decomposition on matrix H to obtain... orthogonal matrix U, The orthogonal matrix V and the non-negative diagonal matrix S; Step 217, move the front of S Each element is set to 0 to construct a new diagonal matrix. The matrix is ​​obtained by reconstructing using singular values. Based on matrix Obtain the noise-reduced vibration signal .

3. The method for assessing the aging status of a pumped storage unit's GCB according to claim 2, characterized in that, A is 10.

4. The method for assessing the aging status of a pumped storage unit's GCB according to claim 2, characterized in that, The specific steps for removing white noise using the relevant scaling method are as follows: Step 221: Perform wavelet transform on the vibration signal containing white noise to obtain... , This represents the noisy signal at position n on scale j. Discrete wavelet transform; Step 222: Calculate the correlation coefficient , ; Step 223: Calculate the normalized correlation value , , , ; Step 224: Compare normalized correlation values and wavelet transform values The reconstructed wavelet transform values ​​are obtained. : like Then The value assigned The corresponding position; like ,but The corresponding position is assigned a value of 0; Step 225, As a new Repeat steps 222 to 224, with the loop terminating under the following condition: The corresponding wavelet transform energy is less than the threshold of noise energy; Step 226, for the obtained Wavelet transform is performed to obtain the signal after removing white noise.

5. The method for assessing the aging status of a pumped storage unit's GCB according to claim 1, characterized in that, Step 5 specifically involves: remaining lifespan. , , , To allow for a certain number of disconnections, For relative electrical wear during a single interruption, The relative electrical wear is denoted by z switching cycles.

6. A pumped storage unit GCB aging status assessment system, characterized in that, include: Data acquisition unit: used to acquire vibration signals; Denoising unit: The acquired vibration signal is denoised based on singular value decomposition, and then white noise is removed by correlation scaling method; Feature parameter acquisition unit: Acquires feature parameters based on the signal after removing white noise, including: mean. Standard deviation Root mean square value skewness and waveform factor ; Aging Condition Correction Factor Calculation Unit: Calculates the aging condition correction factor of the pumped storage unit's GCB based on characteristic parameters. : ; Aging Status Assessment Unit: Assess the aging status of the GCB based on the aging status correction factor.

7. The pumped storage unit GCB aging status assessment system according to claim 6, characterized in that, The data acquisition unit includes an acceleration vibration sensor, a constant current source adapter, and a data acquisition card.

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