Method and system for evaluating harmonic emission level of new energy station based on recording data

Abstract

The invention discloses a new energy station harmonic emission level evaluation method and system based on recording data, and the method comprises the steps: carrying out the wavelet threshold de-noising processing of the recording data of line current and bus voltage in a power grid, and then carrying out the Fourier analysis, and obtaining the amplitude and phase angle of each harmonic current and voltage; on the basis of the amplitude and phase angle of each harmonic current and voltage, the harmonic order to be analyzed is determined through the harmonic voltage content rate and the harmonic distortion rate, an abnormal bus is screened as a concerned bus, and suspicious harmonic source users in the power grid are identified; establishing an equivalent model of the power grid, and solving harmonic transfer impedance between each suspicious harmonic source user and the concerned bus in the equivalent model by using a blind source separation algorithm; and quantifying the harmonic responsibility of each suspicious harmonic source user to the concerned bus. According to the invention, the accuracy of harmonic evaluation and the accuracy of tracing are improved, and the improvement of the electric energy quality of a new energy station and the stable operation of a power grid are facilitated.

Description

Technical Field

[0001] The present invention relates to a harmonic emission level assessment method and system for assessing the harmonic emission level of a new energy station based on recorded data. Background Art

[0002] Against the backdrop of increasingly severe global climate change and energy crisis, the development and utilization of renewable energy as a clean and sustainable form of energy has received widespread attention and importance. New energy sites, such as wind farms and photovoltaic power stations, as the main carriers of renewable energy power generation, are gradually becoming an important part of the power system. However, with the continuous expansion of the scale of new energy sites and the widespread application of power electronic equipment, harmonic problems have become increasingly prominent, posing a severe challenge to the stability of the power grid and the quality of power.

[0003] Harmonics are a type of non-sinusoidal electrical quantity in the power system. Their presence can cause additional losses, heat and vibration in electrical equipment in the power grid, accelerate equipment aging and reduce equipment life. At the same time, harmonics can also interfere with the communication and protection systems of the power system, affecting the overall performance and reliability of the power system. In new energy sites, the harmonic problem is particularly prominent due to the nonlinear characteristics of new energy equipment such as wind power generation and photovoltaic power generation and the extensive use of power electronic devices.

[0004] At present, the harmonic emission level assessment of new energy sites mainly relies on theoretical calculations and simulation analysis. However, these methods are often based on simplified models and assumptions, and it is difficult to accurately reflect the harmonic emission level of new energy sites under actual operating conditions. In addition, the operating conditions of new energy sites are complex and changeable, and are affected by multiple factors such as wind speed, light, and temperature, making the harmonic emission level assessment more difficult. Summary of the invention

[0005] In order to solve the problems of inaccurate harmonic evaluation and inexact source tracing in the prior art, the present invention provides a method and system for evaluating the harmonic emission level of a new energy station based on recorded data.

[0006] The present invention adopts the following technical solution.

[0007] The first aspect of the present invention proposes a method for evaluating harmonic emission levels of new energy stations based on recorded data, comprising:

[0008] The recorded data of line current and bus voltage in the power grid are subjected to wavelet threshold denoising and then Fourier analysis to obtain the amplitude and phase angle of each harmonic current and voltage;

[0009] Based on the amplitude and phase angle of each harmonic current and voltage, the harmonic order to be analyzed is determined through the harmonic voltage content rate and harmonic distortion rate, the abnormal bus is selected as the bus of concern, and the suspicious harmonic source users in the power grid are identified;

[0010] Establish an equivalent model of the power grid and solve the harmonic transfer impedance between each suspicious harmonic source user and the concerned bus in the equivalent model;

[0011] Based on the harmonic transfer impedance and the amplitude and phase angle of each harmonic voltage and current, the harmonic responsibility of each suspected harmonic source user to the concerned bus is quantified, and the harmonic responsibility represents the harmonic emission level of each suspected harmonic source user.

[0012] Preferably, the wavelet threshold denoising process is performed on the recorded data of the line current and bus voltage in the power grid, specifically:

[0013] Decomposing the j-layer wavelet decomposition of the line current and bus voltage in the power grid into a series of wavelet functions, each layer including a high-frequency wavelet function and a low-frequency wavelet function, the decomposed series of wavelet functions are all obtained by scaling and translating a set mother wavelet function, and the scaling and translating amount is represented by the wavelet coefficient;

[0014] Filter as follows:

[0015]

[0016] Among them, w is the threshold set, d j,k is the wavelet coefficient of the kth wavelet function of the jth layer, is the wavelet coefficient of the kth wavelet function of the jth layer after filtering, k∈[0,1], when k is 0, the kth wavelet function represents the high-frequency wavelet function of this layer, and when k is 1, the kth wavelet function represents the low-frequency wavelet function of this layer.

[0017] Preferably, based on the amplitude and phase angle of each harmonic current and voltage, the harmonic order to be analyzed is determined through the harmonic voltage content rate and the harmonic distortion rate, and the abnormal bus is selected as the concerned bus, specifically:

[0018] Calculate the content rate of each harmonic voltage. If a certain harmonic voltage exceeds the set harmonic voltage content rate threshold, it is the harmonic order to be analyzed;

[0019] Calculate the voltage harmonic distortion rate and the total voltage harmonic distortion rate of all harmonic orders to be analyzed; and the average value of the voltage harmonic distortion rate and the total voltage harmonic distortion rate of all harmonic orders to be analyzed within the set n sampling periods, and calculate the comprehensive distortion rate index:

[0020]

[0021] Where M is the total number of harmonics to be analyzed, ΔTHD m THD is the average value of the voltage harmonic distortion rate change of the mth harmonic to be analyzed within n sampling cycles; m is the voltage harmonic distortion rate of the mth harmonic order to be analyzed; H m is the harmonic voltage content rate of the mth harmonic order to be analyzed; ΔTHD is the average value of the change of the total voltage harmonic distortion rate; THD is the total voltage harmonic distortion rate;

[0022] If the comprehensive distortion rate index on a bus exceeds the set harmonic distortion rate threshold, the bus will be regarded as a focus bus.

[0023] Preferably, the identifying of suspicious harmonic source users in the power grid is specifically:

[0024] Count all users that have harmonic power exchange with the bus of interest, and the direction of harmonic power exchange is from the user to the bus. Judge among these users. If the user's harmonic power exceeds the set power threshold, or the user type is an arc furnace, data center, or new energy station, the user is a suspected harmonic source user.

[0025] Preferably, the establishing of the equivalent model of the power grid is specifically as follows:

[0026]

[0027] Where: U Xh with U X,0h represent the h-th harmonic voltage of the X-th concerned bus and the h-th background harmonic voltage respectively; the background harmonic voltage is the harmonic voltage of other harmonic source users on the concerned bus except the suspicious harmonic source users; U X,hI is the hth harmonic voltage of the ith suspicious harmonic source user on the Xth concerned bus, I c,hi represents the hth harmonic current measured at the common connection point after the ith suspected harmonic source user is connected; Z X,hi It represents the hth harmonic transfer impedance between the suspicious harmonic source user i on the Xth concerned bus and the concerned bus X; N represents the number of suspicious harmonic source users.

[0028] Preferably, a blind source separation algorithm is used to solve the harmonic transfer impedance between each suspicious harmonic source user and the concerned bus in the equivalent model, specifically:

[0029] The hth harmonic voltage of the i-th suspicious harmonic source user on the X-th concerned bus is divided into a fast-changing component and a slow-changing component by a filter:

[0030]

[0031] Among them, U X,hi,f Indicates the fast-changing component of the hth harmonic voltage, U X,hi,s Indicates the slow-changing component of the hth harmonic voltage, I c,hi,f It represents the fast-changing component of the hth harmonic current measured at the common connection point after the corresponding i-th suspected harmonic source user is connected, I c,hi,s It represents the slowly changing component of the hth harmonic current measured at the common connection point after the corresponding i-th suspected harmonic source user is connected;

[0032] Using the blind source separation algorithm to X,hi,f Unmixing is performed to obtain the separation matrix W and independent components,

[0033]

[0034] Among them, W -1 1,i represents the value of the 1st row and the ith column of the inverse matrix of the separation matrix W, W -1 i+1,i Represents the value of the i+1th row and ith column of the inverse matrix of the separation matrix W.

[0035] Preferably, the harmonic responsibility of each suspicious harmonic source user on the concerned bus is quantified based on the harmonic transfer impedance and the amplitude and phase angle of each harmonic voltage and current, specifically:

[0036] The quantified harmonic responsibility of the suspected harmonic source user i to the Xth concerned bus is given by:

[0037]

[0038] Among them, U Xh and represents the hth harmonic voltage of the Xth busbar of interest; U X,hI is the hth harmonic voltage of the ith suspicious harmonic source user on the Xth concerned bus; cos<θ(n)> is U X,hI with U Xh The angle between them; H is the total number of harmonics to be analyzed.

[0039] The second aspect of the present invention provides a harmonic emission level assessment system for a new energy station based on recorded data using the assessment method described in the first aspect of the present invention, comprising a data acquisition module, a data denoising module, a bus screening module, a harmonic source identification module, an impedance solution module and a harmonic responsibility quantification module, characterized in that:

[0040] Data acquisition module, used to collect the recorded data of line current and bus voltage in the power grid;

[0041] Data denoising module: used to perform wavelet threshold denoising on the recorded data of line current and bus voltage in the power grid and then perform Fourier analysis to obtain the amplitude and phase angle of each harmonic current and voltage;

[0042] Bus screening module: used to screen abnormal buses as concerned buses based on the results of harmonic analysis;

[0043] Harmonic source identification module: used to identify suspicious harmonic source users;

[0044] Impedance solving module, used to solve the harmonic transfer impedance between each suspected harmonic source user and the concerned bus;

[0045] The harmonic responsibility quantification module is used to quantify the harmonic responsibility of each suspicious harmonic source user on the concerned bus based on the harmonic transfer impedance and the amplitude and phase angle of each harmonic voltage and current.

[0046] The third aspect of the present invention proposes an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the computer program, when loaded into the processor, implements the method for evaluating the harmonic emission level of a new energy station based on recorded data according to the first aspect of the present invention.

[0047] The fourth aspect of the present invention proposes a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, it implements the method for evaluating the harmonic emission level of a new energy station based on recorded data according to the first aspect of the present invention.

[0048] The beneficial effect of the present invention is that, compared with the prior art, the beneficial effect of the present invention is that it provides a more accurate and practical method for evaluating the harmonic emission level of new energy stations. By performing wavelet threshold denoising on the line current recording data and bus voltage recording data in the power grid, the high-frequency noise of the power grid is reduced. The amplitude and phase angle of each harmonic voltage and current obtained by Fourier analysis are used to determine the harmonic order to be analyzed, and abnormal buses and suspicious harmonic source users are screened, which effectively narrows the scope of harmonic tracing and improves work efficiency. By using the blind source separation algorithm, the harmonic transfer impedance between each suspicious harmonic source user and the bus of concern is solved, and then the harmonic responsibility of each suspicious harmonic source user to the bus of concern is quantified, which improves the pertinence and effectiveness of harmonic governance, and also provides a scientific basis for the harmonic management of new energy stations, which helps to ensure the stable operation of the power grid and the improvement of power quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 It is a flow chart of the present invention. DETAILED DESCRIPTION

[0050] In order to make the purpose, technical scheme and advantages of the present invention clearer, the technical scheme of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The embodiments described in this application are only part of the embodiments of the present invention, not all of them. Based on the spirit of the present invention, other embodiments obtained by ordinary technicians in this field without creative work are all within the scope of protection of the present invention.

[0051] like Figure 1 As shown, Embodiment 1 of the present invention proposes a method for evaluating harmonic emission levels of new energy stations based on recorded wave data, including:

[0052] The recorded data of line current and bus voltage in the power grid are subjected to wavelet threshold denoising and then Fourier analysis to obtain the amplitude and phase angle of each harmonic current and voltage;

[0053] Preferably, the wavelet threshold denoising process is performed on the recorded data of the line current and bus voltage in the power grid, specifically:

[0054] Decomposing the j-layer wavelet decomposition of the line current and bus voltage in the power grid into a series of wavelet functions, each layer including a high-frequency wavelet function and a low-frequency wavelet function, the decomposed series of wavelet functions are all obtained by scaling and translating a set mother wavelet function, and the scaling and translating amount is represented by the wavelet coefficient;

[0055] Filter as follows:

[0056]

[0057] Among them, w is the threshold set, d j,k is the wavelet coefficient of the kth wavelet function of the jth layer, is the wavelet coefficient of the kth wavelet function of the jth layer after filtering, k∈[0,1], when k is 0, the kth wavelet function represents the high-frequency wavelet function of this layer, and when k is 1, the kth wavelet function represents the low-frequency wavelet function of this layer.

[0058] Based on the amplitude and phase angle of each harmonic current and voltage, the harmonic order to be analyzed is determined through the harmonic voltage content rate and harmonic distortion rate, the abnormal bus is selected as the bus of concern, and the suspicious harmonic source users in the power grid are identified;

[0059] Preferably, based on the amplitude and phase angle of each harmonic current and voltage, the harmonic order to be analyzed is determined through the harmonic voltage content rate and the harmonic distortion rate, and the abnormal bus is selected as the concerned bus, specifically:

[0060] Calculate the content rate of each harmonic voltage. If a certain harmonic voltage exceeds the set harmonic voltage content rate threshold, it is the harmonic order to be analyzed;

[0061] Calculate the voltage harmonic distortion rate and the total voltage harmonic distortion rate of all harmonic orders to be analyzed; and the average value of the voltage harmonic distortion rate and the total voltage harmonic distortion rate of all harmonic orders to be analyzed within the set n sampling periods, and calculate the comprehensive distortion rate index:

[0062]

[0063] Where M is the total number of harmonics to be analyzed, ΔTHD m THD is the average value of the voltage harmonic distortion rate change of the mth harmonic to be analyzed within n sampling cycles; m is the voltage harmonic distortion rate of the mth harmonic order to be analyzed; H m is the harmonic voltage content rate of the mth harmonic order to be analyzed; ΔTHD is the average value of the change of the total voltage harmonic distortion rate; THD is the total voltage harmonic distortion rate;

[0064] If the comprehensive distortion rate index on a bus exceeds the set harmonic distortion rate threshold, the bus will be regarded as a focus bus.

[0065] Preferably, the identifying of suspicious harmonic source users in the power grid is specifically:

[0066] Count all users that have harmonic power exchange with the bus of interest, and the direction of harmonic power exchange is from the user to the bus. Judge among these users. If the user's harmonic power exceeds the set power threshold, or the user type is an arc furnace, data center, or new energy station, the user is a suspected harmonic source user.

[0067] Establish an equivalent model of the power grid and solve the harmonic transfer impedance between each suspicious harmonic source user and the concerned bus in the equivalent model;

[0068] Preferably, the establishing of the equivalent model of the power grid is specifically as follows:

[0069]

[0070] Where: U Xh with U X,0h represent the h-th harmonic voltage of the X-th concerned bus and the h-th background harmonic voltage respectively; the background harmonic voltage is the harmonic voltage of other harmonic source users on the concerned bus except the suspicious harmonic source users; U X,hI is the hth harmonic voltage of the ith suspicious harmonic source user on the Xth concerned bus, I c,hirepresents the hth harmonic current measured at the common connection point after the ith suspected harmonic source user is connected; Z X,hi It represents the hth harmonic transfer impedance between the suspicious harmonic source user i on the Xth concerned bus and the concerned bus X; N represents the number of suspicious harmonic source users.

[0071] Preferably, a blind source separation algorithm is used to solve the harmonic transfer impedance between each suspicious harmonic source user and the concerned bus in the equivalent model, specifically:

[0072] The hth harmonic voltage of the i-th suspicious harmonic source user on the X-th concerned bus is divided into a fast-changing component and a slow-changing component by a filter:

[0073]

[0074] Among them, U X,hi,f Indicates the fast-changing component of the hth harmonic voltage, U X,hi,s Indicates the slow-changing component of the hth harmonic voltage, I c,hi,f It represents the fast-changing component of the hth harmonic current measured at the common connection point after the corresponding i-th suspected harmonic source user is connected, I c,hi,s It represents the slowly changing component of the hth harmonic current measured at the common connection point after the corresponding i-th suspected harmonic source user is connected;

[0075] Using the blind source separation algorithm to X,hi,f Unmixing is performed to obtain the separation matrix W and independent components,

[0076]

[0077] Among them, W -1 1,i represents the value of the 1st row and the ith column of the inverse matrix of the separation matrix W, W -1 i+1,i Represents the value of the i+1th row and ith column of the inverse matrix of the separation matrix W.

[0078] Based on the harmonic transfer impedance and the amplitude and phase angle of each harmonic voltage and current, the harmonic responsibility of each suspected harmonic source user to the concerned bus is quantified, and the harmonic responsibility represents the harmonic emission level of each suspected harmonic source user.

[0079] Preferably, the harmonic responsibility of each suspicious harmonic source user on the concerned bus is quantified based on the harmonic transfer impedance and the amplitude and phase angle of each harmonic voltage and current, specifically:

[0080] The quantified harmonic responsibility of the suspected harmonic source user i to the Xth concerned bus is given by:

[0081]

[0082] Among them, U Xh and represents the hth harmonic voltage of the Xth busbar of interest; U X,hI is the hth harmonic voltage of the ith suspicious harmonic source user on the Xth concerned bus; cos<θ(n)> is U X, h I with U Xh The angle between them; H is the total number of harmonics to be analyzed.

[0083] Embodiment 2 of the present invention proposes a harmonic emission level assessment system for a new energy station based on recorded data using the assessment method described in Embodiment 1 of the present invention, including a data acquisition module, a data denoising module, a bus screening module, a harmonic source identification module, an impedance solution module, and a harmonic responsibility quantification module:

[0084] Data acquisition module, used to collect the recorded data of line current and bus voltage in the power grid;

[0085] Data denoising module: used to perform wavelet threshold denoising on the recorded data of line current and bus voltage in the power grid and then perform Fourier analysis to obtain the amplitude and phase angle of each harmonic current and voltage;

[0086] Bus screening module: used to screen abnormal buses as concerned buses based on the results of harmonic analysis;

[0087] Harmonic source identification module: used to identify suspicious harmonic source users;

[0088] Impedance solving module, used to solve the harmonic transfer impedance between each suspected harmonic source user and the concerned bus;

[0089] The harmonic responsibility quantification module is used to quantify the harmonic responsibility of each suspicious harmonic source user on the concerned bus based on the harmonic transfer impedance and the amplitude and phase angle of each harmonic voltage and current.

[0090] Embodiment 3 of the present invention proposes an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor. When the computer program is loaded into the processor, the method for evaluating the harmonic emission level of a new energy station based on recorded data according to Embodiment 1 of the present invention is implemented.

[0091] Embodiment 4 of the present invention proposes a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, it implements the method for evaluating the harmonic emission level of a new energy station based on recorded data according to Embodiment 1 of the present invention.

Claims

1. A method for evaluating harmonic emission levels of new energy stations based on recorded data, characterized in that: include: The recorded data of line current and bus voltage in the power grid are subjected to wavelet threshold denoising and then Fourier analysis to obtain the amplitude and phase angle of each harmonic current and voltage; Based on the amplitude and phase angle of each harmonic current and voltage, the harmonic order to be analyzed is determined through the harmonic voltage content rate and harmonic distortion rate, the abnormal bus is selected as the bus of concern, and the suspicious harmonic source users in the power grid are identified; Establish an equivalent model of the power grid and solve the harmonic transfer impedance between each suspicious harmonic source user and the concerned bus in the equivalent model; Based on the harmonic transfer impedance and the amplitude and phase angle of each harmonic voltage and current, the harmonic responsibility of each suspected harmonic source user to the concerned bus is quantified, and the harmonic responsibility represents the harmonic emission level of each suspected harmonic source user.

2. According to claim 1, a method for evaluating harmonic emission levels of new energy stations based on recorded data is characterized in that: The wavelet threshold denoising process is performed on the recorded data of the line current and bus voltage in the power grid, specifically: Decomposing the j-layer wavelet decomposition of the line current and bus voltage in the power grid into a series of wavelet functions, each layer including a high-frequency wavelet function and a low-frequency wavelet function, the decomposed series of wavelet functions are all obtained by scaling and translating a set mother wavelet function, and the scaling and translating amount is represented by the wavelet coefficient; Filter as follows: Among them, w is the threshold set, d j,k is the wavelet coefficient of the kth wavelet function of the jth layer, is the wavelet coefficient of the kth wavelet function of the jth layer after filtering, k∈[0,1], when k is 0, the kth wavelet function represents the high-frequency wavelet function of this layer, and when k is 1, the kth wavelet function represents the low-frequency wavelet function of this layer.

3. According to claim 1, a method for evaluating harmonic emission levels of new energy stations based on recorded data is characterized in that: Based on the amplitude and phase angle of each harmonic current and voltage, the harmonic order to be analyzed is determined through the harmonic voltage content rate and harmonic distortion rate, and the abnormal bus is selected as the concerned bus, specifically: Calculate the content rate of each harmonic voltage. If a certain harmonic voltage exceeds the set harmonic voltage content rate threshold, it is the harmonic order to be analyzed; Calculate the voltage harmonic distortion rate and the total voltage harmonic distortion rate of all harmonic orders to be analyzed; and the average value of the voltage harmonic distortion rate and the total voltage harmonic distortion rate of all harmonic orders to be analyzed within the set n sampling periods, and calculate the comprehensive distortion rate index: Where M is the total number of harmonics to be analyzed, ΔTHD m THD is the average value of the voltage harmonic distortion rate change of the mth harmonic to be analyzed within n sampling cycles; m is the voltage harmonic distortion rate of the mth harmonic order to be analyzed; H m is the harmonic voltage content rate of the mth harmonic order to be analyzed; ΔTHD is the average value of the change of the total voltage harmonic distortion rate; THD is the total voltage harmonic distortion rate; If the comprehensive distortion rate index on a bus exceeds the set harmonic distortion rate threshold, the bus will be regarded as a focus bus.

4. According to claim 3, a method for evaluating harmonic emission levels of new energy stations based on recorded data is characterized in that: The identification of suspicious harmonic source users in the power grid is specifically as follows: Count all users that have harmonic power exchange with the bus of interest, and the direction of harmonic power exchange is from the user to the bus. Judge among these users. If the user's harmonic power exceeds the set power threshold, or the user type is an arc furnace, data center, or new energy station, the user is a suspected harmonic source user.

5. According to claim 3, a method for evaluating harmonic emission levels of new energy stations based on recorded data is characterized in that: The equivalent model of the power grid is established as follows: Where: U Xh with U X,0h represent the h-th harmonic voltage of the X-th concerned bus and the h-th background harmonic voltage respectively; the background harmonic voltage is the harmonic voltage of other harmonic source users on the concerned bus except the suspicious harmonic source users; U X,hI is the hth harmonic voltage of the ith suspicious harmonic source user on the Xth concerned bus, I c,hi represents the hth harmonic current measured at the common connection point after the ith suspected harmonic source user is connected; Z X,hi It represents the hth harmonic transfer impedance between the suspicious harmonic source user i on the Xth concerned bus and the concerned bus X; N represents the number of suspicious harmonic source users.

6. A method for evaluating harmonic emission levels of new energy stations based on recorded data according to claim 5, characterized in that: The blind source separation algorithm is used to solve the harmonic transfer impedance between each suspicious harmonic source user and the concerned bus in the equivalent model, which is: The hth harmonic voltage of the i-th suspicious harmonic source user on the X-th concerned bus is divided into a fast-changing component and a slow-changing component by a filter: Among them, U X,hi,f Indicates the fast-changing component of the hth harmonic voltage, U X,hi,s Indicates the slow-changing component of the hth harmonic voltage, I c,hi,f It represents the fast-changing component of the hth harmonic current measured at the common connection point after the corresponding i-th suspected harmonic source user is connected, I c,hi,s It represents the slowly changing component of the hth harmonic current measured at the common connection point after the corresponding i-th suspected harmonic source user is connected; Using the blind source separation algorithm to X,hi,f Unmixing is performed to obtain the separation matrix W and independent components, Among them, W -1 1,i represents the value of the 1st row and the ith column of the inverse matrix of the separation matrix W, W -1 i+1,i Represents the value of the i+1th row and ith column of the inverse matrix of the separation matrix W.

7. A method for evaluating harmonic emission levels of new energy stations based on recorded data according to claim 6, characterized in that: The harmonic responsibility of each suspicious harmonic source user on the concerned bus is quantified based on the harmonic transfer impedance and the amplitude and phase angle of each harmonic voltage and current, specifically: The quantified harmonic responsibility of the suspected harmonic source user i to the Xth concerned bus is: Among them, U Xh and represents the hth harmonic voltage of the Xth busbar of interest; U X,hI is the hth harmonic voltage of the ith suspicious harmonic source user on the Xth concerned bus; cos<θ(n)> is U X, h I with U Xh The angle between them; H is the total number of harmonics to be analyzed.

8. A harmonic emission level assessment system for new energy stations based on recorded data using the assessment method according to any one of claims 1 to 7, comprising a data acquisition module, a data denoising module, a bus screening module, a harmonic source identification module, an impedance solution module and a harmonic responsibility quantification module, characterized in that: Data acquisition module, used to collect the recorded data of line current and bus voltage in the power grid; Data denoising module: used to perform wavelet threshold denoising on the recorded data of line current and bus voltage in the power grid and then perform Fourier analysis to obtain the amplitude and phase angle of each harmonic current and voltage; Bus screening module: used to screen abnormal buses as concerned buses based on the results of harmonic analysis; Harmonic source identification module: used to identify suspicious harmonic source users; Impedance solving module, used to solve the harmonic transfer impedance between each suspected harmonic source user and the concerned bus; The harmonic responsibility quantification module is used to quantify the harmonic responsibility of each suspicious harmonic source user on the concerned bus based on the harmonic transfer impedance and the amplitude and phase angle of each harmonic voltage and current.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the computer program is loaded into a processor, it implements the method for evaluating harmonic emission levels of new energy stations based on recorded data according to any one of claims 1-8.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the method for evaluating harmonic emission levels of new energy stations based on recorded data according to any one of claims 1 to 8 is implemented.

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