Electric energy quality compensation method and equipment for new energy access power grid

Abstract

The invention relates to the technical field of transformer intelligent optimization compensation, in particular to an electric energy quality compensation method and equipment for new energy access to a power grid, and the method comprises the steps: connecting a dynamic voltage compensation converter in series at the low-voltage side of a transformer, and connecting a high-power bidirectional converter in parallel at the load side of a terminal, acquiring the voltage of the low-voltage side of the transformer at each moment in each period, and recording the voltage as transformer voltage; acquiring load current and load voltage at each moment in each period of the load side of the terminal; determining the influence weight of harmonic disturbance, the influence weight of reactive power disturbance and the influence weight of voltage out-of-limit in each period; constructing a target function; and obtaining an optimal power factor, each harmonic current component and each transformer voltage in the current period by utilizing an intelligent optimization algorithm and combining the objective function, and respectively performing transformer voltage compensation, reactive compensation and harmonic current compensation on the current period. Therefore, the overall stability of electric energy quality is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of intelligent optimization compensation of transformers, in particular to a power quality compensation method and device for new energy access to a power grid. BACKGROUND

[0002] The grid-connected access of new energy power such as photovoltaic and wind power to a power system can cause a decrease in power quality. Power quality affects the normal operation of power equipment, and in serious cases can cause problems such as three-phase imbalance, voltage fluctuation, and harmonics, which pose a serious threat to the stability and reliability of the power grid. Power electronic converters can regulate power to solve power quality problems and ensure that the output meets the user load frequency and voltage requirements. A combination of series and parallel voltage source converters can dynamically respond to real-time conditions such as load changes and harmonic fluctuations in the power system. Series voltage source converters can adjust voltage fluctuations in real time to balance voltage stability, while parallel voltage source converters can provide timely compensation when the load fluctuates or the reactive power demand changes, ensuring the stability of the power system.

[0003] Existing intelligent compensation methods often only detect and manage one type of power quality problem, rely on a single control strategy, lack flexibility, and cannot effectively address complex multi-objective optimization problems, resulting in low power quality stability. SUMMARY

[0004] To solve the above technical problems, the purpose of the present application is to provide a power quality compensation method and device for new energy access to a power grid, and the technical solution adopted is as follows: In a first aspect, the embodiments of the present application provide a power quality compensation method for new energy access to a power grid, which comprises the following steps: A dynamic voltage compensation converter is connected in series at the low-voltage side of a transformer, and a high-power bidirectional converter is connected in parallel at the terminal load side. The voltage at each time in each cycle at the low-voltage side of the transformer is collected and recorded as the transformer voltage. The load current and load voltage at each time in each cycle at the terminal load side are collected; Based on the load current at all times in each cycle, each harmonic current component is obtained, and the total harmonic distortion rate of each cycle is obtained. The influence weight of each cycle harmonic disturbance is determined by the degree of change of the total harmonic distortion rate of each cycle relative to the historical cycle; Based on the load current and the load voltage, the power factor of each cycle at the terminal load side is obtained, and the influence weight of each cycle reactive power disturbance is determined by the degree of deviation of the power factor of each cycle from the historical cycle; The influence weight of each cycle voltage out-of-limit is determined based on the difference degree of the transformer voltage fluctuation of each cycle compared to the historical cycle; Based on the transformer voltage, load current and load voltage collected in each cycle, the current power quality state index is calculated, and the influence weight of each cycle harmonic disturbance, the influence weight of reactive power disturbance and the influence weight of voltage out-of-limit are determined to construct a multi-objective optimization objective function including total harmonic distortion, power factor and transformer voltage deviation; By using intelligent optimization algorithm, the optimal power factor, each harmonic current component and each transformer voltage of the current cycle are obtained by combining the target function, and transformer voltage compensation, reactive compensation and harmonic current compensation are performed on the current cycle.

[0005] In one embodiment, the determination of the influence weight of each cycle harmonic disturbance includes: The ratio of the total harmonic distortion of each cycle to the average of the total harmonic distortions of all previous cycles is calculated, denoted as the first ratio, and when the first ratio is greater than or equal to the value 1, the influence weight of the corresponding cycle harmonic disturbance is 1, otherwise, the influence weight of the corresponding cycle harmonic disturbance is the first ratio.

[0006] In one embodiment, the determination of the influence weight of each cycle reactive power disturbance includes: The ratio of the power factor of each cycle to the average of the power factors of all previous cycles is calculated, denoted as the second ratio, and the influence weight of each cycle reactive power disturbance is the normalized result of the second ratio.

[0007] In one embodiment, the determination of the influence weight of each cycle voltage out-of-limit includes: The ratio of the transformer voltage variance of each cycle to the average of the transformer voltage variances of all previous cycles is calculated, denoted as the third ratio, and if the third ratio is greater than or equal to the value 1, the influence weight of the corresponding cycle voltage out-of-limit is 1, otherwise, the influence weight of the corresponding cycle voltage out-of-limit is the third ratio.

[0008] In one embodiment, the expression of the target function is: In the formula, is the target function value of the jth cycle, , , are the influence weights of the jth cycle harmonic disturbance, reactive power disturbance and voltage out-of-limit, respectively; is the total harmonic distortion of the jth cycle; is the power factor of the jth cycle; is the ith transformer voltage sampling value of the jth cycle, is the average voltage in the cycle, and N is the number of sampling points; the effective value of the rated voltage of the low-voltage side of the transformer; The specific calculation method is, wherein is the effective value of the kth harmonic current component of the jth period, M is the total number of harmonic current components, and V is the effective value of the fundamental component of the jth period.

[0009] In an embodiment, the initial particles of the intelligent optimization algorithm are: the harmonic current components, the power factor, and the transformer voltage of a preset number of periods before each period.

[0010] In an embodiment, the transformer voltage compensation includes: The Clarke transformation is used to obtain the component and the component of the optimized transformer voltage at each moment of the current period, which are denoted as and respectively; based on the preset rated voltage amplitude and the phase angle θ of the current moment, the calculation method of the axis component and the axis component of the transformer voltage compensation at each moment is: In the formula, is a trigonometric sine function, is a trigonometric cosine function, is the grid fundamental phase angle obtained through a phase-locked loop.

[0011] In an embodiment, the calculation method of the compensation amount of the reactive power compensation is: In the formula, is the compensation amount of the reactive power compensation of the current period, is the active power collected in the current period, is the power factor collected in the current period, is the optimized power factor of the current period.

[0012] In an embodiment, the compensation amount of the harmonic current compensation is the difference between the optimal harmonic current component and the preset target harmonic current value.

[0013] In a second aspect, the embodiments of the present application further provide an electric energy quality compensation device for new energy access to a power grid, which comprises a memory, a processor, and a computer program stored in the memory and running on the processor, and the processor implements the steps of the method according to any one of the above embodiments when executing the computer program.

[0014] The application has at least the following beneficial effects: The application has at least the following beneficial effects: BRIEF DESCRIPTION OF DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, and the advantages thereof, a brief introduction will be given to the drawings needed in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor.

[0016] Figure 1A step flow chart of a power quality compensation method for new energy access to a power grid is provided in an embodiment of the present application. Figure 2 A flow chart is determined for the target function. DETAILED DESCRIPTION

[0017] In order to further illustrate the technical means and effects adopted by the present application to achieve the predetermined purposes, the specific embodiments, structures, features and effects of the power quality compensation method and device for new energy access to a power grid according to the present application are described in detail below in combination with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. In addition, the specific features, structures or characteristics in one or more embodiments can be combined in any suitable form.

[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs.

[0019] The specific scheme of the power quality compensation method and device for new energy access to a power grid provided by the present application is specifically described below in combination with the accompanying drawings.

[0020] Please refer to Figure 1 which shows a step flow chart of a power quality compensation method for new energy access to a power grid provided in an embodiment of the present application, which method comprises the following steps: S1, a dynamic voltage compensation converter is connected in series at the low-voltage side of a transformer, a high-power bidirectional converter is connected in parallel at the terminal load side, the voltage at each time in each cycle at the low-voltage side of the transformer is collected and recorded as the transformer voltage, and the load current and load voltage at each time in each cycle at the terminal load side are collected.

[0021] The embodiment is connected in series with a dynamic voltage compensation converter based on PWM (Pulse Width Modulation) control at the low-voltage side of the transformer for suppressing low-order harmonics and voltage fluctuations of the transformer output voltage. The converter is connected to the low-voltage bus through a phase-shift transformer. A voltage transformer with a transformation ratio of 400V / 100V is installed at the three-phase four-wire bus at the low-voltage side of the transformer to collect bus voltage signals at each time in each cycle, which is recorded as the transformer voltage. At the same time, a high-power bidirectional converter is connected in parallel at the terminal load side to compensate for load harmonic current and reactive power. The load-side current signal at each time in each cycle is collected by a closed-loop Hall sensor and recorded as the load current. The load-side voltage signal at each time in each cycle is collected by a voltage transformer with a transformation ratio of 220V / 5V and recorded as the load voltage. In this embodiment, the transformer voltage, load voltage, and load current are synchronously collected, with a sampling frequency of 5kHz and a processing period of 10ms. The implementer can set the sampling frequency and the length of the period according to the actual situation, which is not limited in this embodiment.

[0022] The transformer voltage at all times in each cycle is taken as the input of a low-pass filter to eliminate high-frequency noise. The output is the denoised transformer voltage at all times in each cycle. The denoised transformer voltage is normalized by the maximum-minimum value normalization method. The load current at all times in each cycle and the load voltage at all times in each cycle are denoised and normalized by the same denoising and normalization method as the transformer voltage at all times in each cycle to obtain the denoised and normalized transformer voltage, load current, and load voltage at all times in each cycle. The low-pass filter and the maximum-minimum value normalization method are both known technologies, and this embodiment will not be described in detail.

[0023] S2, based on the load current at all times in each cycle, obtains each harmonic current component to obtain the total harmonic distortion rate of each cycle. The influence weight of the harmonic disturbance of each cycle is determined by the degree of change of the total harmonic distortion rate of each cycle relative to the historical cycle.

[0024] With a high proportion of photovoltaic access to the distribution network, due to the randomness and strong dispersion of photovoltaic, it has a high impact on the stability of power quality, making the power quality disturbance present high complexity. In order to deal with power quality problems, it is usually necessary to adjust the power by means of power electronic converter and compensate the current and voltage to some extent, so as to ensure the stability of power quality. The traditional compensation method is difficult to cope with the real-time influence of photovoltaic access on power quality, so it is difficult to compensate in time to ensure the stability of power quality; at the same time, the traditional compensation method often relies on a single control strategy, and the compensation for the power quality fluctuation caused by photovoltaic access lacks sufficient flexibility and comprehensiveness.

[0025] In power distribution networks, multiple issues affecting power quality may coexist. Changes in voltage and current are the result of the interaction of these issues. Calculating compensation based on these results can alleviate some of the problems, but it's difficult to solve all issues simultaneously or achieve an optimal balance. Therefore, this embodiment first analyzes transformer voltage, reactive power, and harmonics, and then performs multi-objective optimization based on the compensation results to achieve the final optimal compensation.

[0026] In power distribution networks, common issues affecting power quality include reactive power, harmonics, and voltage exceeding limits. Therefore, voltage and current compensation are necessary to ensure power quality meets the requirements of the power supply system. To calculate the voltage and current compensation amounts, it is necessary to calculate the effective values ​​of voltage and current, active power, reactive power, and harmonic current for each cycle based on the collected voltage and current data.

[0027] In this embodiment, the normalized load current at all times in each cycle is first processed using a fast Fourier transform algorithm to obtain the corresponding frequency domain data, the harmonic current components of each cycle are obtained, and the total harmonic distortion rate of the load current in each cycle is calculated. The fast Fourier transform algorithm, the acquisition of harmonic current components, and the calculation of the total harmonic distortion rate are all existing known technologies, and the specific process will not be described in detail.

[0028] Among the various issues affecting power quality, the greater the degree of variation in the corresponding parameters relative to historical periods, the more severe the impact on power quality. Therefore, in subsequent multi-objective optimization, these issues require greater weight to enhance compensation for disturbances and improve power quality. Thus, it is necessary to calculate the corresponding impact weights based on the variation of various issues, specifically: , It is the first The influence weight of harmonic disturbances within each period For the first The total harmonic distortion rate of each cycle is the same as the previous one. The ratio of the average total harmonic distortion (THD) over each period is denoted as the first ratio. It can be understood that the smaller the THD, the smaller the degree of harmonic disturbance, and therefore the smaller the impact of harmonics on power quality. The corresponding influence weight is then determined accordingly. The smaller it is.

[0029] S3. Based on the load current and the load voltage, obtain the power factor of each cycle on the terminal load side, and determine the influence weight of reactive power disturbance in each cycle by utilizing the degree of deviation between the power factor of each cycle and the historical cycle.

[0030] Based on the normalized load voltage and load current at all times of each cycle, the active power and the reactive power of each cycle are calculated, so as to calculate the power factor of each cycle. It should be noted that the calculation of the active power, the reactive power and the power factor of each cycle is a known technology, and the specific process will not be described here.

[0031] , is the influence weight of the reactive power disturbance in the first cycle, is a normalization function, is the ratio of the power factor of the first cycle to the average of the power factors of the previous cycles, which is referred to as the second ratio. It can be understood that the greater the influence of the reactive power disturbance on the power quality, the smaller the corresponding power factor, and thus the greater the corresponding influence weight .

[0032] S4, based on the difference degree of the transformer voltage fluctuation of each cycle compared with the historical cycle, the influence weight of the voltage out-of-limit of each cycle is determined.

[0033] The disturbance of the voltage occurs in real time, and the voltage is an approximate sine wave, which is also constantly fluctuating and changing. Therefore, the variance of the transformer voltage data in each cycle is used to measure the fluctuation of the voltage. The voltage out-of-limit problem, i.e. the excessive or insufficient fluctuation of the voltage, exceeds the normal fluctuation range, and thus can also be reflected by the variance. Therefore, the calculation method of the influence weight of the voltage out-of-limit is: , is the influence weight of the voltage out-of-limit in the first cycle, is the third ratio, , is the variance of the transformer voltage in the first cycle, is the average of the transformer voltage variances of the previous cycles. It can be understood that the more serious the voltage out-of-limit, the more serious the disturbance to the power quality, and the greater the corresponding transformer voltage variance, and thus the greater the corresponding influence weight .

[0034] S5, based on the transformer voltage, the load current and the load voltage collected in each cycle, the current power quality state index is calculated, and the influence weight of the harmonic disturbance, the influence weight of the reactive power disturbance and the influence weight of the voltage out-of-limit are combined to construct a multi-objective optimization objective function containing the total harmonic distortion rate, the power factor and the transformer voltage deviation.

[0035] To achieve comprehensive and optimal power quality management, this embodiment abandons the independent compensation method with a single objective and instead adopts a multi-objective joint optimization strategy. After collecting the current voltage and current data, physical compensation is not immediately executed. Instead, an objective function reflecting the comprehensive power quality index is first constructed. This objective function comprehensively considers the influence of three dimensions: harmonics, reactive power, and voltage fluctuations. The weighting coefficients determined in steps S2 to S4 are used to dynamically adjust the optimization priority of each dimension, thereby providing a mathematical model basis for subsequent calculation of the optimal compensation command.

[0036] During data acquisition, this embodiment also collects the transformer voltage at each moment within each cycle, as well as the load current and load voltage at each moment within each cycle on the terminal load side. To optimize transformer voltage compensation, reactive power compensation, and harmonic current compensation for the current cycle, this embodiment first obtains the transformer voltage, load current, and load voltage collected in the previous G cycles of the current cycle. Based on the load current, a fast Fourier transform algorithm is used to obtain the fundamental component and each harmonic current component. In this embodiment, G=60, but the implementer can set it according to the actual situation.

[0037] On the terminal load side, based on the load voltage and load current collected in each cycle, the power factor of each cycle in the first G cycles and the harmonic current components of each cycle are obtained; the transformer voltage collected at each moment in each cycle in the first G cycles is obtained.

[0038] Historical data from the previous G cycles is obtained, including power factor, harmonic current components, and transformer voltage. The power factor, all harmonic current components, and all transformer voltages of each cycle are used as the initial particles for the intelligent optimization algorithm. When compensating for each cycle, the objective function used differs due to varying power quality disturbances. (The text then continues with a discussion of the G cycles, which is not directly related to the previous sentence.) Taking the objective function for one cycle as an example, based on each harmonic current component, power factor, and transformer voltage, the specific expression of the objective function is as follows: In the formula, Let j be the objective function value in the j-th period. , , These are the weights of the impact of harmonic disturbance, reactive power disturbance, and voltage over-limit in the j-th cycle, respectively. Let be the total harmonic distortion rate of the j-th period; Let be the power factor in the j-th cycle; This represents the i-th transformer voltage sample value in the j-th cycle. The average voltage over the period is N, where N is the number of sampling points. This is the effective value of the rated voltage on the low-voltage side of the transformer; in this embodiment, it is taken as 220V.

[0039] The specific calculation method is as follows: ,in Let M be the effective value of the k-th harmonic current component in the j-th period, M be the total number of harmonic current components, and V be the effective value of the fundamental component in the j-th period. If the objective function... The smaller the value, the better the overall power quality.

[0040] The flowchart for determining the objective function is as follows: Figure 2 As shown.

[0041] It is understandable that, in order to ensure power quality after compensation, it is necessary to minimize the power quality disturbances caused by harmonics, reactive power, and voltage over-limits, and to maximize the difference in disturbance changes before and after compensation. Therefore, the objective function mentioned above is used to optimize the objective function so that it is greater than 0 and reaches its minimum value, that is, the closer the objective function is to 0, the better.

[0042] S6. Using an intelligent optimization algorithm and the objective function, obtain the optimal power factor, harmonic current components, and transformer voltage for the current cycle, and perform transformer voltage compensation, reactive power compensation, and harmonic current compensation for the current cycle.

[0043] Assuming the j-th period is the current period, this embodiment utilizes the objective function, combined with all initial particles, and employs a multi-objective particle swarm optimization algorithm for optimization, where the number of particles is... Maximum number of iterations In this embodiment The implementer can set the inertia weights themselves. Initial learning factor Each particle's initial velocity is set to 0. A multi-objective particle swarm optimization algorithm is used to output the first particle. The optimal power factor, harmonic current components, and transformer voltage values ​​are determined during energy compensation in each cycle. The multi-objective particle swarm optimization algorithm is a well-known existing technology, and its specific process will not be elaborated upon. Based on the harmonic current components in the optimal solution, harmonic current compensation can be performed; based on the power factor in the optimal solution, reactive power disturbance compensation can be performed; and based on the transformer voltage values ​​in the optimal solution, voltage compensation on the low-voltage side of the transformer can be performed. The specific compensation method is as follows: For transformer voltage compensation, firstly, the Clarke transform is used to obtain the optimized transformer voltage at each moment of the current period. Components and Component, denoted as and In order to calculate the compensation amount, the rated voltage amplitude of the system standard is set , corresponding to 220V effective value. The fundamental phase angle θ of the locked phase loop output in real time is used to construct the reference voltage trajectory.

[0044] The alpha-axis component of the transformer voltage compensation amount and the beta-axis component are obtained by subtracting the actual value from the reference value respectively, and the specific calculation formula is: is a trigonometric sine function, is a trigonometric cosine function, is the grid fundamental phase angle obtained through the phase-locked loop.

[0045] The compensation method for the reactive power disturbance, i.e., the reactive compensation, is: ; in the formula, is the compensation amount of the reactive compensation in the current period, is the active power collected in the current period, is the power factor collected in the current period, is the optimized power factor in the current period.

[0046] The compensation amount for each harmonic current component is the difference between each harmonic current component in the optimal solution and the preset target harmonic current value, wherein, for even harmonics, the target harmonic current value is 3% of the fundamental component, and for odd harmonics, the target harmonic current value is 5% of the fundamental component. The implementer can set it according to the actual situation, which is not limited in the embodiment.

[0047] Based on the same inventive concept as the above method, the embodiment of the present application also provides an electric energy quality compensation device for new energy access to the grid, which comprises a memory, a processor, and a computer program stored in the memory and running on the processor, and the processor implements the steps of any one of the methods in the above-mentioned electric energy quality compensation method for new energy access to the grid.

[0048] It should be noted that: the above-mentioned sequence of the embodiments of the present application is only for description, and does not represent the advantages and disadvantages of the embodiments. And the above describes the specific embodiments of the present application. In addition, the processes depicted in the drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multi-task processing and parallel processing are also possible or can be advantageous.

[0049] The various embodiments in the specification are described in progressive manner, and the same or similar parts between the various embodiments can be mutually referred to, and each embodiment focuses on the difference from other embodiments.

[0050] The above only describes the preferred embodiments of the present application, and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the principles of the present application shall be included in the protection scope of the present application.

Claims

1. A power quality compensation method for new energy grid connection, characterized in that, The method includes the following steps: A dynamic voltage compensation converter is connected in series on the low-voltage side of the transformer, and a high-power bidirectional converter is connected in parallel on the terminal load side. The voltage at each moment in each cycle on the low-voltage side of the transformer is collected and recorded as the transformer voltage; the load current and load voltage at each moment in each cycle on the terminal load side are collected. Based on the load current at all times within each cycle, the harmonic current components are obtained to obtain the total harmonic distortion rate of each cycle; by the degree of variation of the total harmonic distortion rate of each cycle relative to the historical cycle, the influence weight of harmonic disturbances in each cycle is determined. Based on the load current and the load voltage, the power factor of each cycle on the terminal load side is obtained, and the influence weight of reactive power disturbance in each cycle is determined by the degree of deviation between the power factor of each cycle and the historical cycle. Based on the degree of difference in transformer voltage fluctuations between each cycle and historical cycles, the impact weight of voltage exceeding the limit in each cycle is determined; Based on the transformer voltage, load current and load voltage collected in each cycle, the current power quality status index is calculated. Combined with the determined influence weights of harmonic disturbances, reactive power disturbances and voltage over-limits in each cycle, a multi-objective optimization objective function including total harmonic distortion, power factor and transformer voltage deviation is constructed. Using an intelligent optimization algorithm and the objective function, the optimal power factor, harmonic current components, and transformer voltage for the current cycle are obtained. Transformer voltage compensation, reactive power compensation, and harmonic current compensation are then performed for the current cycle.

2. The power quality compensation method for new energy grid connection as described in claim 1, characterized in that, The determination of the influence weights of each periodic harmonic disturbance includes: The ratio of the total harmonic distortion rate of each period to the mean of the total harmonic distortion rates of all previous periods is calculated and denoted as the first ratio. When the first ratio is greater than or equal to 1, the influence weight of the harmonic disturbance of the corresponding period is 1; otherwise, the influence weight of the harmonic disturbance of the corresponding period is the first ratio.

3. The power quality compensation method for new energy grid access as described in claim 1, characterized in that, The determination of the impact weights of reactive power disturbances in each cycle includes: The ratio of the power factor of each cycle to the mean of the power factors of all previous cycles is calculated and denoted as the second ratio. The influence weight of reactive power disturbance in each cycle is the normalized result of the second ratio.

4. The power quality compensation method for new energy grid connection as described in claim 1, characterized in that, The determination of the impact weight of voltage exceedance in each cycle includes: Calculate the ratio of the transformer voltage variance at all times in each cycle to the mean of the transformer voltage variance in all previous cycles, and denot it as the third ratio. If the third ratio is greater than or equal to 1, the influence weight of the voltage exceeding the limit in the corresponding cycle is 1; otherwise, the influence weight of the voltage exceeding the limit in the corresponding cycle is the third ratio.

5. The power quality compensation method for new energy grid access as described in claim 1, characterized in that, The expression for the objective function is: In the formula, Let j be the objective function value in the j-th period. , , These are the weights of the impact of harmonic disturbance, reactive power disturbance, and voltage over-limit in the j-th cycle, respectively. Let be the total harmonic distortion rate of the j-th period; Let be the power factor in the j-th cycle; This represents the i-th transformer voltage sample value in the j-th cycle. The average voltage over the period is N, where N is the number of sampling points. This is the effective value of the rated voltage on the low-voltage side of the transformer; The specific calculation method is as follows: ,in Let M be the effective value of the kth harmonic current component in the jth period, M be the total number of harmonic current components, and V be the effective value of the fundamental component in the jth period.

6. The power quality compensation method for new energy grid connection as described in claim 1, characterized in that, The initial particles of the intelligent optimization algorithm are: each harmonic current component, power factor, and transformer voltage of each cycle, which are preset in a certain number of cycles before each cycle.

7. The power quality compensation method for new energy grid access as described in claim 1, characterized in that, The transformer voltage compensation includes: The optimized transformer voltage at each moment of the current period is obtained using the Clarke transform. Components and The components are denoted as follows: and Based on the preset rated voltage amplitude And the phase angle θ at the current moment, the transformer voltage compensation at each moment Axial components and The calculation method for shaft components is as follows: In the formula, It is a trigonometric sine function. It is a trigonometric cosine function. This is the fundamental phase angle of the power grid obtained through a phase-locked loop.

8. The power quality compensation method for new energy grid access as described in claim 1, characterized in that, The calculation method for the reactive power compensation amount is as follows: In the formula, This is the amount of reactive power compensation for the current cycle. This represents the active power collected in the current cycle. The power factor collected in the current cycle. This is the optimized power factor for the current cycle.

9. The power quality compensation method for new energy grid connection as described in claim 1, characterized in that, The compensation amount of the harmonic current compensation is the difference between each optimal harmonic current component and the preset target harmonic current value.

10. A power quality compensation device for new energy grid connection, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the method as described in any one of claims 1-9.

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