A method for extracting signal characteristics in dynamic process of power system

Abstract

The present invention discloses a method for extracting signal characteristics in the dynamic process of an electric power system, comprising: collecting and transforming the three-phase instantaneous signal at the PCC point of the electric power system into an αβ axis voltage component; then extracting the instantaneous amplitude and instantaneous frequency through amplitude locking and phase locking, then extracting the steady-state amplitude and the amplitude modulation corresponding to the disturbance through filtering, and extracting the steady-state frequency and the frequency modulation corresponding to the disturbance through filtering; digitally filtering the amplitude modulation and the frequency modulation to obtain the αβ axis component of the positive sequence rotating vector; multiplying the αβ axis components by 2, and then extracting the amplitude frequency of the signal modulation mode through amplitude locking and phase locking. The signal characteristics extracted by the present invention include the steady-state amplitude frequency and the amplitude frequency of the signal modulation mode, which can accurately reflect the characteristics and laws of the alternating current electrical quantity changes in the dynamic process of the system.

Description

Technical Field

[0001] The present invention belongs to the technical field of power system stability control, and more specifically, relates to a method for extracting signal characteristics in a dynamic process of a power system. Background Art

[0002] At present, the power system signal analysis methods are divided into the following categories: Fourier transform directly regards the signal as the sum of multiple signals with constant amplitude and frequency; Prony algorithm decomposes the signal into a linear combination of complex exponential functions with different frequencies, amplitudes and attenuation damping; short-time Fourier transform and wavelet analysis, by changing the time window size, characterize the amplitude frequency of the signal in each shorter time period, and approximately characterize the frequency change of the signal in the total time. However, the above signal analysis methods do not recognize that the signal characteristics in the dynamic process of the power system are the steady-state amplitude frequency and the amplitude frequency of the disturbance modulation quantity on the amplitude frequency. It is difficult to describe the changes and laws of the characteristics of the AC electrical quantity in the dynamic process of the power system, which hinders the optimization measures such as the control parameter design and the implementation of additional damping control in the system.

[0003] Therefore, how to correctly extract signal characteristics in the dynamic process of power system is a technical problem that needs to be solved urgently. Summary of the invention

[0004] In view of the defects of the prior art, the purpose of the present invention is to provide a method for extracting signal characteristics in the dynamic process of the power system. The extracted signal characteristics include the steady-state amplitude frequency and the amplitude frequency of the signal modulation mode, which can accurately reflect the changes and laws of the characteristics of AC electrical quantities in the dynamic process of the system, which is conducive to monitoring and early warning of system oscillations, and effectively guides the implementation of system optimization measures such as controller parameter design and additional damping control implementation.

[0005] To achieve the above object, the present invention provides a method for extracting signal features in a dynamic process of a power system, comprising the following steps:

[0006] (1) Collect the three-phase voltage instantaneous signal at the common connection point of the power system, and transform the three-phase voltage instantaneous signal into the αβ axis voltage component u by two-phase stationary coordinate system. α and u β ;

[0007] (2) The αβ axis voltage component u α and u β After amplitude locking and phase locking, the instantaneous amplitude A(t) and instantaneous frequency w(t) of the internal potential rotation vector corresponding to the three-phase voltage instantaneous signal are extracted, and then the instantaneous amplitude A(t) is respectively extracted through low-pass filtering and high-pass filtering to obtain the steady-state amplitude A0 and the amplitude modulation corresponding to the disturbance. The instantaneous frequency w(t) is respectively subjected to low-pass filtering and high-pass filtering to extract the steady-state frequency w0 and the frequency modulation corresponding to the disturbance.

[0008] (3) The amplitude modulation amount and frequency modulation amount After digital filtering, the amplitude modulation amount is obtained and frequency modulation amount The αβ axis components of the corresponding positive sequence rotation vector;

[0009] (4) The amplitude modulation amount The αβ axis component of the corresponding positive sequence rotating vector is multiplied by 2, and then the amplitude frequency A of the amplitude oscillation is extracted through amplitude locking and phase locking. A and w A , and at the same time the frequency modulation amount The αβ axis component of the corresponding positive sequence rotating vector is multiplied by 2, and then the amplitude frequency A of the frequency oscillation is extracted through amplitude locking and phase locking. w and w w , the steady-state amplitude A0, steady-state frequency w0, amplitude oscillation amplitude frequency A A and w A , the amplitude frequency of the frequency oscillation A w and w w The signal characteristics that constitute the dynamic process of the power system.

[0010] The method for extracting signal characteristics in the dynamic process of the power system provided by the present invention recognizes the amplitude-frequency modulation mechanism of the signal in the dynamic process of the system by analyzing the formation and evolution process of the AC voltage and current in the dynamic process of the power system, obtains the instantaneous amplitude A(t) and instantaneous frequency w(t) by amplitude locking and phase locking, and obtains all the characteristics of the amplitude-frequency modulated signal by low-pass, high-pass and digital filtering. It can accurately reflect the changes and laws of the characteristics of AC electrical quantities in the dynamic process of the system, is conducive to monitoring and early warning of system oscillations, and effectively guides the implementation of system optimization measures such as controller parameter design and additional damping control implementation.

[0011] In one embodiment, in step (2), the αβ axis voltage component u α and u β After amplitude locking and phase locking, the steps of extracting the instantaneous amplitude A(t) and instantaneous frequency w(t) are as follows:

[0012] The αβ axis voltage component u α and u β The dq rotating coordinate axis voltage component u is obtained by Park transformation d and u q ;

[0013] with u q = 0 is the control target, negative feedback is introduced, and the voltage component u q Through PI controller adjustment, the adjustment amount and the initial frequency w s Superposition, get the instantaneous frequency w pll (t);

[0014] The instantaneous frequency w pll (t) The instantaneous phase θ is obtained by the integrator pll , through the instantaneous phase θ pll Adjust the phase of the dp rotation coordinate system in the park transformation. When adjusted to u q = 0, u d is the instantaneous amplitude A(t), w pll (t) is the instantaneous frequency w(t).

[0015] In one embodiment, in step (2), the αβ axis voltage component u is converted into α and u β After amplitude and phase locking, the instantaneous amplitude A(t) and instantaneous frequency w(t) are extracted.

[0016] In one embodiment, in step (2), the instantaneous amplitude A(t) and the instantaneous frequency w(t) are respectively low-pass filtered by a low-pass filter to obtain a steady-state amplitude A0 and a frequency w0; the instantaneous amplitude A(t) and the instantaneous frequency w(t) are respectively high-pass filtered by a high-pass filter to obtain an amplitude modulation amount and frequency modulation amount

[0017] In one embodiment, step (3) is specifically:

[0018] The amplitude modulation amount The difference is made between the α-axis component of the initial positive sequence rotating vector and the α-axis component of the initial negative sequence rotating vector, and the difference is made between zero and the β-axis component of the initial positive sequence rotating vector and the β-axis component of the initial negative sequence rotating vector; then the two differences are passed through the first positive sequence rotating vector amplitude integrator and a gain to obtain the amplitude modulation amount. The αβ axis components of the corresponding positive sequence rotating vector; wherein the transfer function in the first positive sequence rotating vector amplitude integrator

[0019]

[0020] At the same time, the frequency modulation amount The difference is made between the α-axis component of the initial positive sequence rotating vector and the α-axis component of the initial negative sequence rotating vector, and the difference is made between zero and the β-axis component of the initial positive sequence rotating vector and the β-axis component of the initial negative sequence rotating vector; then the two differences are passed through the second positive sequence rotating vector amplitude integrator and a gain to obtain the frequency modulation amount The αβ axis components of the corresponding positive sequence rotating vector; the transfer function in the second positive sequence rotating vector amplitude integrator is:

[0021]

[0022] In one embodiment, in step (3), the amplitude modulation amount is filtered by a positive sequence component filter. and frequency modulation amount After digital filtering, the amplitude modulation amount is obtained and frequency modulation amount The αβ-axis components of the corresponding positive-sequence rotation vector.

[0023] In one embodiment, in step (4), a standard second-order phase-locked loop is used to modulate the amplitude and frequency modulation amount The α and β axis components of the corresponding positive sequence rotating vector are respectively phase-locked to extract the amplitude frequency A of the amplitude oscillation. A and w A and the amplitude frequency of the frequency oscillation A w and w w . BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a flow chart of a method for extracting signal features in a dynamic process of a power system provided by an embodiment of the present invention;

[0025] Figure 2 yes Figure 1 Principle block diagram of the method for extracting signal features in the dynamic process of power system;

[0026] Figure 3 yes Figure 1 Control strategy diagram for signal feature extraction method in power system dynamic process;

[0027] Figure 4 This is a control model diagram of amplitude locking and phase locking provided by an embodiment of the present invention;

[0028] Figure 5 is a relationship diagram between various quantities and the rotation vector provided by the present invention;

[0029] Figure 6 is a control model diagram of a digital filter provided by an embodiment of the present invention;

[0030] Figure 7 is a structural schematic diagram of a converter grid-connected system provided by a specific embodiment of the present invention;

[0031] Figure 8 yes Figure 7 A waveform diagram of signal characteristics extracted by the extraction method provided by the present invention in a medium converter grid-connected system. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0033] In order to solve the problem that the signal features extracted by the traditional power system signal analysis method cannot accurately reflect the changes and laws of the AC electrical quantity (three-phase oscillation signal) in the dynamic process of the power system, the three-phase oscillation signal of the power system is extracted. a 、e b and e c The formation and evolution process of is analyzed and the following oscillation signal expression is obtained:

[0034]

[0035] From formula (1), we can see that by extracting the steady-state amplitude frequency A0 and w0 in the power system and the amplitude frequency of the signal modulation mode, we can accurately reflect the changes and laws of the characteristics of the AC electrical quantity in the dynamic process of the system. Among them, the amplitude frequency of the modulation mode includes the amplitude of the amplitude oscillation A A , the frequency w of the amplitude oscillation A , the amplitude of the frequency oscillation A w The frequency of the oscillation is w w .

[0036] Figure 1 is a flow chart of a method for extracting signal features in a dynamic process of a power system provided by an embodiment of the present invention, such as Figure 1 As shown, the extraction method includes steps S10 to S40, which are described in detail as follows:

[0037] S10, collect the three-phase voltage instantaneous signal u at the common connection point (PCC point) of the power system a 、u b and u c , and the three-phase voltage instantaneous signal u a 、u b and u c Perform a two-phase stationary coordinate system transformation (Clark transformation) to obtain the αβ axis voltage component u α and u β.

[0038] It can be understood that for the three-phase voltage of the power system, the instantaneous value of the three-phase voltage and its corresponding internal potential rotation vector E can be expressed as:

[0039]

[0040] The calculation formula of the Clark transformation provided in this embodiment is:

[0041]

[0042] S20, such as Figure 2 and 3 As shown, the αβ axis voltage component u α and u β After amplitude locking and phase locking, the instantaneous amplitude A(t) and instantaneous frequency w(t) of the internal potential rotation vector E corresponding to the three-phase voltage signal are extracted, and then the instantaneous amplitude A(t) is extracted through low-pass filtering to obtain the steady-state amplitude A0 and the amplitude modulation corresponding to the disturbance. The instantaneous frequency w(t) is respectively subjected to high-pass filtering to extract the steady-state frequency w0 and the frequency modulation corresponding to the disturbance.

[0043] In this embodiment, if Figure 4 As shown, the αβ axis voltage component u α and u β The steps of extracting the instantaneous amplitude A(t) and the instantaneous frequency w(t) through amplitude locking and phase locking may specifically be:

[0044] Step 1: Convert the αβ axis voltage component u α and u β The dq rotating coordinate axis voltage component u is obtained by Park transformation d and u q .

[0045] Step 2: Use u q = 0 is the control target, negative feedback is introduced, and the voltage component u q Through PI controller adjustment, the adjustment amount and the initial frequency w s Superposition, get the instantaneous frequency w pll (t);

[0046] Step 3: Convert the instantaneous frequency w pll (t) The instantaneous phase θ is obtained by the integrator pll , through the instantaneous phase θ pll Adjust the phase of the dp rotation coordinate system in the park transformation, such as Figure 5 As shown, when adjusted to u q = 0, u dis the instantaneous amplitude A(t), w pll (t) is the instantaneous frequency w(t).

[0047] Furthermore, the control strategy of steps 1 to 3 above can be adopted by using a standard second-order phase-locked loop to convert the αβ axis voltage component u α and u β After amplitude locking and phase locking, the instantaneous amplitude A(t) and instantaneous frequency w(t) of the internal potential rotation vector E corresponding to the three-phase oscillation signal are extracted.

[0048] Furthermore, the instantaneous amplitude A(t) and the instantaneous frequency w(t) can be respectively low-pass filtered by a low-pass filter to obtain a steady-state amplitude A0 and frequency w0; the instantaneous amplitude A(t) and the instantaneous frequency w(t) can be respectively high-pass filtered by a high-pass filter to obtain an amplitude modulation amount and frequency modulation amount

[0049] S30, the amplitude modulation amount and frequency modulation amount After digital filtering, the amplitude modulation amount is obtained and frequency modulation amount The αβ-axis components of the corresponding positive-sequence rotation vector.

[0050] In step S30, Figure 6 As shown, the amplitude modulation After digital filtering, the steps of obtaining the αβ axis components of the positive sequence rotating vector can be specifically as follows:

[0051] The amplitude modulation The difference is made between the α-axis component of the initial positive sequence rotating vector and the α-axis component of the initial negative sequence rotating vector, and the difference is made between zero and the β-axis component of the initial positive sequence rotating vector and the β-axis component of the initial negative sequence rotating vector; then the two differences are passed through a positive sequence rotating vector amplitude integrator and a gain to obtain the amplitude modulation amount. The αβ axis components of the corresponding positive sequence rotating vector. Among them, the transfer function in the positive sequence rotating vector amplitude integrator provided in this embodiment is

[0052]

[0053] It can be understood that for the amplitude modulation There are the following expressions:

[0054]

[0055] The amplitude modulation The difference is made between the α-axis component of the initial positive sequence rotating vector and the α-axis component of the initial negative sequence rotating vector, and the difference is made between zero and the β-axis component of the initial positive sequence rotating vector and the β-axis component of the initial negative sequence rotating vector; then the two differences are passed through a positive sequence rotating vector amplitude integrator and a gain to obtain the amplitude modulation amount. The corresponding αβ axis components of the positive sequence rotating vector. At the same time, the two differences are passed through a negative sequence rotating vector amplitude integrator and a gain to obtain the amplitude modulation amount. The αβ axis components of the corresponding negative sequence rotating vector. Among them, the transfer function in the positive sequence rotating vector amplitude integrator in this embodiment is The transfer function in the negative sequence rotating vector magnitude integrator is:

[0056] After the above transformation, the αβ axis components of the positive sequence rotating vector output by the digital filter are and Starts from 0 and increases until it is equal to the positive sequence rotation vector The instantaneous value of the component on the αβ axis, at the same time, the αβ axis component of the output negative sequence rotating vector and Starts from 0 and increases until it is equal to the negative sequence rotation vector The instantaneous value of the component on the αβ axis. At this time, the amplitude modulation The difference between the α-axis component of the initial positive-sequence rotating vector and the α-axis component of the initial negative-sequence rotating vector is 0, and the difference between the β-axis component of the initial positive-sequence rotating vector and the β-axis component of the initial negative-sequence rotating vector is also 0, thereby extracting the rotating vector

[0057] Similarly, the frequency modulation After digital filtering, the steps to obtain the αβ axis components of the positive sequence rotating vector are:

[0058] The frequency modulation amount The difference is made between the α-axis component of the initial positive sequence rotating vector and the α-axis component of the initial negative sequence rotating vector, and the difference is made between zero and the β-axis component of the initial positive sequence rotating vector and the β-axis component of the initial negative sequence rotating vector; then the two differences are passed through another positive sequence rotating vector amplitude integrator and a gain to obtain the frequency modulation amount. The αβ axis components of the corresponding positive sequence rotating vector. Wherein, the transfer function in the positive sequence rotating vector amplitude integrator provided in this embodiment is:

[0059]

[0060] S40, since the amplitude of the modulation amount is twice the amplitude of the rotating vector corresponding to the modulation amount, the αβ axis components of the positive sequence rotating vector obtained in step 30 need to be multiplied by 2, and then the amplitude of the amplitude oscillation A is extracted by amplitude locking and phase locking. A , the frequency w of the amplitude oscillation A and the amplitude of the frequency oscillation A w The frequency of the oscillation is w w The extracted steady-state amplitude A0, steady-state frequency w0, and amplitude oscillation amplitude A A , the frequency w of the amplitude oscillation A , the amplitude of the frequency oscillation A w The frequency of the oscillation is w w The signal characteristics of the power system in the dynamic process are formed, and then the change and law of the AC electrical quantity characteristics in the dynamic process of the power system can be determined by the above formula (1).

[0061] In step S40, the amplitude A of the amplitude oscillation is extracted by amplitude locking and phase locking. A , the frequency w of the amplitude oscillation A and the amplitude of the frequency oscillation A w The frequency of the oscillation is w w The principle of this can be found in the amplitude locking and phase locking principle in the aforementioned step S20, which will not be described in detail in this embodiment.

[0062] The method for extracting signal features in the dynamic process of the power system provided in this embodiment recognizes the amplitude-frequency modulation mechanism of the signal in the dynamic process of the system by analyzing the formation and evolution process of the AC voltage and current in the dynamic process of the power system, obtains the instantaneous amplitude A(t) and instantaneous frequency w(t) by amplitude locking and phase locking, and obtains all the features of the amplitude-frequency modulated signal by low-pass, high-pass and digital filtering. It can accurately reflect the changes and laws of the characteristics of AC electrical quantities in the dynamic process of the system, is conducive to monitoring and early warning of system oscillations, and effectively guides the implementation of system optimization measures such as controller parameter design and additional damping control implementation.

[0063] The principle of the present invention is described in detail below in conjunction with specific embodiments:

[0064] Now build the converter grid-connected system in Matlab / Simulink as follows Figure 7 As shown. To simplify the analysis, the converter control part only considers the AC current control (ACC) and phase-locked loop (PLL) ignoring the voltage cross-decoupling and terminal voltage feedforward. The system is in steady-state operation before 3s, and the phase-locked frequency is set to deviate from the steady-state operation point by 0.5rad / s at 3s. After 3s, the system starts to oscillate freely from the initial value after the disturbance.

[0065] The method for extracting signal characteristics in a dynamic process of a power system provided by the present invention comprises the following steps:

[0066] Step 1: Collect the original three-phase instantaneous signal at the PCC point, such as Figure 8 (a) shows that the three-phase instantaneous signal is then transformed into the αβ axis voltage component u by Clark transformation. α and u β .

[0067] Step 2: Use a standard second-order phase-locked loop to lock out the instantaneous amplitude / instantaneous frequency of the internal potential rotation vector corresponding to the three-phase instantaneous signal, such as Figure 8 As shown in the curve in (b).

[0068] Step 3: Use low-pass / high-pass filters to separate the DC value in the instantaneous amplitude / instantaneous frequency of the signal and the modulation value corresponding to the disturbance. The DC value is as follows: Figure 8 The straight line in (b) is the steady-state characteristic of the signal, and the modulation amount is Figure 8 (b) is shown as the difference between the curve and the straight line.

[0069] Step 4: The positive sequence component filter (PSCF) separates the positive sequence rotating vectors from the negative sequence rotating vectors in the modulated signal and only retains the positive sequence rotating vectors.

[0070] Step 5: The amplitude of the rotating vector corresponding to the modulation signal is doubled, and then the modulation characteristics of the modulation signal are extracted through a second-order phase-locked loop, such as Figure 8 As shown in (c), at this point, all the characteristics of the amplitude-frequency modulation signal are obtained.

[0071] In the above steps, the corresponding relationship between the instantaneous value of the signal and its amplitude / frequency is shown by the arrows in the figure. Since the state presents a divergent oscillation form during the small disturbance dynamic process of the system, the amplitude of the signal amplitude / frequency modulation amount presents an increasing form.

[0072] Finally, the demodulated features of the above signals are substituted into the above formula (1) to calculate the signal amplitude frequency modulation and the original signal respectively. The fitted signal is as follows: Figure 8 The dotted lines in (d) and (e) show the corresponding relationship between the signal features and the fitting signal as shown by the arrows in the figure. By comparing the original signal with the fitting signal, it can be seen that the fitting signal basically coincides with the original signal, proving that the signal extraction method provided by the present invention is very effective.

[0073] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for extracting signal features in a dynamic process of a power system, characterized in that: The steps include: (1) Collect the three-phase voltage instantaneous signal at the common connection point of the power system, and transform the three-phase voltage instantaneous signal into the αβ axis voltage component u by two-phase stationary coordinate system. α and u β ; (2) The αβ axis voltage component u α and u β After amplitude locking and phase locking, the instantaneous amplitude A(t) and instantaneous frequency w(t) of the internal potential rotation vector corresponding to the three-phase voltage instantaneous signal are extracted, and then the instantaneous amplitude A(t) is respectively extracted through low-pass filtering and high-pass filtering to obtain the steady-state amplitude A0 and the amplitude modulation corresponding to the disturbance. The instantaneous frequency w(t) is filtered by low-pass and high-pass filters to extract the steady-state frequency w0 and the frequency modulation corresponding to the disturbance. (3) The amplitude modulation amount and frequency modulation amount After digital filtering, the amplitude modulation amount is obtained and frequency modulation amount The αβ axis components of the corresponding positive sequence rotation vector; (4) The amplitude modulation amount The αβ axis component of the corresponding positive sequence rotating vector is multiplied by 2, and then the amplitude frequency A of the amplitude oscillation is extracted through amplitude locking and phase locking. A and w A , and at the same time the frequency modulation amount The αβ axis component of the corresponding positive sequence rotating vector is multiplied by 2, and then the amplitude frequency A of the frequency oscillation is extracted through amplitude locking and phase locking. w and w w , the steady-state amplitude A0, steady-state frequency w0, amplitude oscillation amplitude frequency A A and w A , the amplitude frequency of the frequency oscillation A w and w w The signal characteristics that constitute the dynamic process of the power system.

2. The method for extracting signal features in a dynamic process of a power system according to claim 1, characterized in that: In step (2), the αβ axis voltage component u α and u β After amplitude locking and phase locking, the steps of extracting the instantaneous amplitude A(t) and instantaneous frequency w(t) are as follows: The αβ axis voltage component u α and u β The dq rotating coordinate axis voltage component u is obtained by Park transformation d and u q ; with u q = 0 is the control target, negative feedback is introduced, and the voltage component u q Through PI controller adjustment, the adjustment amount and the initial frequency w s Superposition, get the instantaneous frequency w pll (t); The instantaneous frequency w pll (t) The instantaneous phase θ is obtained by the integrator pll , through the instantaneous phase θ pll Adjust the phase of the dp rotation coordinate system in the park transformation. When adjusted to u q = 0, u d is the instantaneous amplitude A(t), w pll (t) is the instantaneous frequency w(t).

3. The method for extracting signal features in a dynamic process of a power system according to claim 2, characterized in that: In step (2), the αβ axis voltage component u is converted into α and u β After amplitude and phase locking, the instantaneous amplitude A(t) and instantaneous frequency w(t) are extracted.

4. The method for extracting signal features in a dynamic process of a power system according to claim 1, characterized in that: In step (2), the instantaneous amplitude A(t) and the instantaneous frequency w(t) are respectively subjected to low-pass filtering by a low-pass filter to obtain a steady-state amplitude A0 and a frequency w0; the instantaneous amplitude A(t) and the instantaneous frequency w(t) are respectively subjected to high-pass filtering by a high-pass filter to obtain an amplitude modulation amount and frequency modulation amount 5. The method for extracting signal features in a dynamic process of a power system according to claim 1, characterized in that: Step (3) is specifically as follows: The amplitude modulation amount The difference is made between the α-axis component of the initial positive sequence rotating vector and the α-axis component of the initial negative sequence rotating vector, and the difference is made between zero and the β-axis component of the initial positive sequence rotating vector and the β-axis component of the initial negative sequence rotating vector; then the two differences are passed through the first positive sequence rotating vector amplitude integrator and a gain to obtain the amplitude modulation amount. The αβ axis components of the corresponding positive sequence rotating vector; wherein the transfer function in the first positive sequence rotating vector amplitude integrator At the same time, the frequency modulation amount The difference is made between the α-axis component of the initial positive sequence rotating vector and the α-axis component of the initial negative sequence rotating vector, and the difference is made between zero and the β-axis component of the initial positive sequence rotating vector and the β-axis component of the initial negative sequence rotating vector; then the two differences are passed through the second positive sequence rotating vector amplitude integrator and a gain to obtain the frequency modulation amount The αβ axis components of the corresponding positive sequence rotating vector; the transfer function in the second positive sequence rotating vector amplitude integrator is:

6. The method for extracting signal features in a dynamic process of a power system according to claim 5, characterized in that: In step (3), the amplitude modulation amount is filtered by a positive sequence component filter. and frequency modulation amount After digital filtering, the amplitude modulation amount is obtained and frequency modulation amount The αβ axis components of the corresponding positive sequence rotation vector.

7. The method for extracting signal features in a dynamic process of a power system according to claim 1, characterized in that: In step (4), a standard second-order phase-locked loop is used to modulate the amplitude and frequency modulation amount The α and β axis components of the corresponding positive sequence rotating vector are respectively phase-locked to extract the amplitude frequency A of the amplitude oscillation. A and w A and the amplitude frequency of the frequency oscillation A w and w w .

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