CN115622063A - A photovoltaic power station harmonic analysis and control method and system under a new energy grid - Google Patents

Abstract

The invention discloses a photovoltaic power station harmonic analysis and treatment method and system under a new energy grid. The system includes establishing a photovoltaic power station and a superior regional power grid model according to the equipment, lines, structure and harmonic data of the photovoltaic power station and the data of the upper-level power grid; Obtain the background harmonics of the upper-level regional power grid busbar and the inverter of the photovoltaic power station, and establish the harmonic model of the photovoltaic power station according to the background harmonics; according to the harmonic model of the photovoltaic power station, calculate the harmonic output of the photovoltaic power station. The content rate of the harmonic evaluation point of the upper-level regional grid bus; the background harmonics of the upper-level regional grid bus harmonic evaluation point and the output harmonics of the photovoltaic power station are superimposed to obtain the final harmonic content of the evaluation point, and the harmonics of the evaluation point are calculated. Filter to obtain the harmonic content rate of the treated photovoltaic power station and the evaluation point of the upper-level regional power grid after treatment. Effectively realize harmonic analysis and control of photovoltaic power plants.

Description

A photovoltaic power station harmonic analysis and control method and system under a new energy grid

technical field

The invention relates to the technical field of harmonic analysis and treatment of photovoltaic power plants, in particular to a method and system for harmonic analysis and treatment of photovoltaic power plants under a new energy grid.

Background technique

With the large-scale development and utilization of new energy mainly based on wind energy and solar energy and the rapid development of new power systems, a large number of power electronic equipment such as converters and inverters have been introduced into the power system, and the characteristics of the power grid have gradually become high penetration and high power electronics. With the evolution in the direction of globalization, a high proportion of photovoltaic power plants are connected to the power grid, causing harmonic problems to the power grid, which have undergone fundamental changes compared with the traditional power grid in the past.

Harmonics in the new energy grid will affect the normal operation of various power equipment. Therefore, it is of great significance to analyze the harmonic problems of photovoltaic power plants and control the output harmonics of photovoltaic power plants.

Contents of the invention

The purpose of this section is to outline some aspects of embodiments of the invention and briefly describe some preferred embodiments. Some simplifications or omissions may be made in this section, as well as in the abstract and titles of this application, to avoid obscuring the purpose of this section, the abstract and titles, and such simplifications or omissions should not be used to limit the scope of the invention.

In view of the above existing problems, the present invention is proposed.

Therefore, the present invention provides a photovoltaic power station harmonic analysis and control method and system under a new energy grid, which can solve the problem of how to effectively control and improve the consumption rate of renewable distributed energy.

In order to solve the above technical problems, the present invention provides the following technical solutions, a method for harmonic analysis and treatment of photovoltaic power plants under a new energy grid, including:

According to the equipment, lines, structure and harmonic data of the photovoltaic power station and the data of the upper-level power grid, establish the model of the photovoltaic power station and the upper-level regional power grid;

Obtain the background harmonics of the upper-level regional power grid busbar and the inverter of the photovoltaic power station, and establish a harmonic model of the photovoltaic power station according to the background harmonics;

According to the harmonic model of the photovoltaic power station, calculate the harmonic content of the harmonic output of the photovoltaic power station in the photovoltaic power station and the upper-level regional grid bus harmonic evaluation point;

Superimpose the background harmonics of the busbar harmonic evaluation point of the superior regional power grid with the output harmonics of the photovoltaic power station to obtain the final harmonic content of the evaluation point, filter the harmonics of the evaluation point, and obtain the evaluation of the photovoltaic power station and the superior regional power grid after governance Harmonic content rate after point treatment.

As a preferred scheme of the photovoltaic power station harmonic analysis and treatment method under the new energy grid in the present invention, wherein: the final harmonic content of the evaluation points includes,

The background harmonics of the evaluation points of the superior power grid and the same sub-harmonics of the output harmonics of the photovoltaic power station are superimposed as follows:

Among them, I _h1 is the hth harmonic current of harmonic source 1, I _h2 is the hth harmonic current of harmonic source 2, θ is the difference between the hth harmonic current of harmonic source 1 and harmonic source 2 the phase angle.

As a preferred solution of the photovoltaic power station harmonic analysis and treatment method under the new energy grid according to the present invention, wherein: the final harmonic content of the evaluation points also includes,

When the phase angle is uncertain, the final harmonic content rate is:

Among them, K is the coefficient corresponding to different harmonic orders.

As a preferred solution of the photovoltaic power station harmonic analysis and treatment method under the new energy grid according to the present invention, wherein: the coefficients corresponding to the different harmonic orders include,

When the harmonic order is three times, the coefficient K corresponding to different harmonic orders is 1.62;

When the harmonic order is fifth, the coefficient K corresponding to different harmonic orders is 1.28;

When the harmonic order is the seventh order, the coefficient K corresponding to different harmonic orders is 0.72;

When the harmonic order is eleventh, the coefficient K corresponding to different harmonic orders is 0.18;

When the harmonic order is thirteenth, the coefficient K corresponding to different harmonic orders is 0.08;

When the harmonic order is ninth or even, the coefficient K corresponding to different harmonic orders is 0.

As a preferred scheme of the photovoltaic power station harmonic analysis and treatment method under the new energy grid in the present invention, wherein: the photovoltaic power station and the upper-level regional power grid model include a power model and a harmonic model,

The power model includes a photovoltaic power station power equivalent model, and the photovoltaic power station power equivalent model includes two parts: a photovoltaic system and a step-up grid-connected system. The photovoltaic system is composed of solar photovoltaic modules connected to inverters, where battery parameters and The control parameters are determined by the actual photovoltaic power station values;

The step-up grid-connection system implements classified grid-connection according to the inverter grid-connection control strategy, wherein the parameters of the transformer are consistent with the transformer parameters of the step-up station of the photovoltaic power station.

As a preferred solution of the photovoltaic power station harmonic analysis and treatment method under the new energy grid according to the present invention, wherein: the background harmonics of the upper-level regional power grid busbar and the photovoltaic power station inverter include,

Before the photovoltaic power station is connected, the harmonic voltage obtained by carrying out the harmonic test on the substation and the power plant at the access point of the photovoltaic power station is used as the background harmonic of the bus bar;

When the photovoltaic power station is not connected, the measured harmonic voltage is the harmonic output by the photovoltaic power station, and the inverter harmonic is the harmonic current content of the photovoltaic inverter under 100% operation. The harmonic source model of the harmonic current content rate under the 100% output of the photovoltaic inverter is superimposed on each inverter, and the harmonic model of the photovoltaic power station is established.

As a preferred solution of the photovoltaic power station harmonic analysis and treatment method under the new energy grid in the present invention, wherein: the filtering includes,

After obtaining the harmonics of the evaluation points, filter the harmonics exceeding the standard when configuring with the SVG method, and then calculate the harmonic content of the evaluation points after configuring the SVG;

If there is still a harmonic exceeding the standard, and it is below the third harmonic, change the SVG configuration filter parameters and placement position, and send out reactive power that can offset the first, second and third harmonics until the harmonic content rate is qualified;

If there are still harmonics exceeding the standard, and it is more than the third harmonic, then change the SVG configuration filter parameters and placement position, send out reactive power that can offset the first, second and third harmonics, and absorb reactive power above the third harmonic Power until the harmonic content rate is qualified.

As a preferred scheme of the photovoltaic power station harmonic analysis and treatment method under the new energy grid in the present invention, wherein: a photovoltaic power station harmonic analysis and treatment system under the new energy grid is characterized in that it includes a grid model Establishment module, harmonic model establishment module, calculation module and filter module,

A power grid model building module, the power grid model building module builds a model of the photovoltaic power station and the upper-level regional power grid according to the size, line, structure, power and harmonic data of the photovoltaic power station;

A harmonic model building module, the harmonic model building module obtains the background harmonics of the upper-level regional power grid busbar and the inverter of the photovoltaic power station, and establishes a photovoltaic power station harmonic model according to the background harmonics;

A calculation module, the calculation module calculates the content rate of the harmonic output of the photovoltaic power plant harmonics in the photovoltaic power plant and the upper-level regional power grid bus harmonic evaluation point according to the photovoltaic power plant harmonic model;

The filtering module, the background harmonics of the upper-level regional grid bus harmonic evaluation points of the filtering module are superimposed on the output harmonics of the photovoltaic power station to obtain the final harmonic content of the evaluation points, and the harmonics of the evaluation points are filtered to obtain Harmonic content rate after treatment of photovoltaic power plants and evaluation points of superior regional power grids.

A computer device includes a memory and a processor, the memory stores a computer program, wherein the processor implements the steps of the above-mentioned method when executing the computer program.

A computer-readable storage medium, on which a computer program is stored, is characterized in that, when the computer program is executed by a processor, the steps of the above method are implemented.

Beneficial effects of the present invention: the present invention proposes a photovoltaic power station harmonic analysis and control method and system under a new energy grid, in order to analyze the harmonic interaction between the new energy grid and the photovoltaic power station, and realize the photovoltaic power station under the new energy grid For the effective control of harmonics, the present invention firstly analyzes the change law of the characteristic harmonics of the photovoltaic power station inverter, and establishes the whole station model of the photovoltaic power station, analyzes the harmonic distribution of the whole station of the photovoltaic power station and the impact of the harmonic output of the photovoltaic power station on the upper power grid The impact of the harmonic control method is given to effectively realize the harmonic analysis and control of photovoltaic power plants.

Description of drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the accompanying drawings that need to be used in the description of the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For Those of ordinary skill in the art can also obtain other drawings based on these drawings without any creative effort. in:

Fig. 1 is a method flow chart of a photovoltaic power station harmonic analysis and control method and system under a new energy grid provided by an embodiment of the present invention;

Fig. 2 is a photovoltaic power station model diagram of a photovoltaic power station harmonic analysis and treatment method and system under a new energy grid provided by an embodiment of the present invention;

Fig. 3 is an internal structure diagram of a method for analyzing and controlling harmonics of a photovoltaic power station under a new energy grid and a computer device of the system provided by an embodiment of the present invention.

detailed description

In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation modes of the present invention will be described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of them. Example. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in the art without creative efforts shall fall within the protection scope of the present invention.

In the following description, a lot of specific details are set forth in order to fully understand the present invention, but the present invention can also be implemented in other ways different from those described here, and those skilled in the art can do it without departing from the meaning of the present invention. By analogy, the present invention is therefore not limited to the specific examples disclosed below.

Second, "one embodiment" or "an embodiment" referred to herein refers to a specific feature, structure or characteristic that may be included in at least one implementation of the present invention. "In one embodiment" appearing in different places in this specification does not all refer to the same embodiment, nor is it a separate or selective embodiment that is mutually exclusive with other embodiments.

The present invention is described in detail in conjunction with schematic diagrams. When describing the embodiments of the present invention in detail, for the convenience of explanation, the cross-sectional view showing the device structure will not be partially enlarged according to the general scale, and the schematic diagram is only an example, which should not limit the present invention. scope of protection. In addition, the three-dimensional space dimensions of length, width and depth should be included in actual production.

At the same time, in the description of the present invention, it should be noted that the orientation or positional relationship indicated by "upper, lower, inner and outer" in the terms is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention. The invention and the simplified description do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and thus should not be construed as limiting the present invention. In addition, the terms "first, second or third" are used for descriptive purposes only, and should not be construed as indicating or implying relative importance.

Unless otherwise specified and limited in the present invention, the term "installation, connection, connection" should be understood in a broad sense, for example: it can be a fixed connection, a detachable connection or an integrated connection; it can also be a mechanical connection, an electrical connection or a direct connection. A connection can also be an indirect connection through an intermediary, or it can be an internal communication between two elements. Those of ordinary skill in the art can understand the specific meanings of the above terms in the present invention in specific situations.

Example 1

Referring to Figures 1-3, it is the first embodiment of the present invention, which provides a method and system for harmonic analysis and control of photovoltaic power plants under a new energy grid, including:

Step 102, according to the equipment, lines, structure and harmonic data of the photovoltaic power station and the data of the upper-level power grid, establish a model of the photovoltaic power station and the upper-level regional power grid;

Among them, the DIGSILENT model of the photovoltaic power station and the upper-level regional power grid is divided into a power model and a harmonic model, and the power model and the harmonic model are shown in Figure 3.

Specifically, the power model of the photovoltaic power station and the upper-level regional power grid is established. The power equivalent model of the photovoltaic power station includes two parts: the photovoltaic system and the step-up grid-connected system. The photovoltaic system is composed of solar photovoltaic modules connected to inverters;

Furthermore, the photovoltaic system model is modeled with the general photovoltaic system model in DIGSILENT. The grid-connected control strategy of the inverter has a variety of control strategies to achieve grid-connected. The inverter of the photovoltaic power station generally adopts the constant power factor control method under MPPT Grid-connected, the photovoltaic power factor is 1.0, and the remaining photovoltaic cell parameters and inverter control parameters are consistent with the actual photovoltaic power station. The step-up grid-connected system is the same as the traditional substation. In DIGSILENT, the transformer is used for modeling, and the transformer participates in the step-up of the photovoltaic power station. The parameters of the substation transformers are consistent, and the upper-level regional power grid model is modeled according to the grid structure in which photovoltaic power plants are integrated into the regional power grid. The upper-level regional power grid includes power plants and substations in the region.

Step 104, obtaining the background harmonics of the upper-level regional power grid busbar and the inverter of the photovoltaic power station, and establishing a photovoltaic power station harmonic model according to the background harmonics;

Among them, the busbar background harmonics that need to be evaluated in power plants and substations refer to the harmonic voltages obtained from the harmonic test of substations and power plants at the access points of photovoltaic power plants before the photovoltaic power plant is connected. The test harmonics do not include photovoltaic power plants. output harmonics.

Specifically, the background harmonics of the bus bar of the upper-level regional power grid and the inverter of the photovoltaic power station include, when the photovoltaic power station is not connected, the harmonic voltage obtained from the harmonic test of the substation and power plant at the access point of the photovoltaic power station, The measured harmonic voltage is used as the bus background harmonic;

Furthermore, when the photovoltaic power station is not connected, the measured harmonic voltage is the harmonic output by the photovoltaic power station, and the inverter harmonic is the harmonic current contained in the photovoltaic inverter under 100% operation. The harmonic source model of the harmonic current content rate under the 100% output of the photovoltaic inverter is superimposed on each inverter to establish the harmonic model of the photovoltaic power station.

Step 106, according to the harmonic model of the photovoltaic power station, calculate the content rate of the harmonic output of the photovoltaic power station in the harmonic evaluation point of the photovoltaic power station and the upper-level regional power grid busbar;

Wherein, the model of the photovoltaic power station and the upper-level regional power grid includes a power model and a harmonic model.

Specifically, the power model includes a power equivalent model of a photovoltaic power station, and the equivalent power model of a photovoltaic power station includes two parts: a photovoltaic system and a step-up grid-connected system, and the photovoltaic system is composed of solar photovoltaic modules connected to inverters, wherein The battery parameters and control parameters are determined by the actual photovoltaic power plant values;

Further, the step-up grid-connection system implements classified grid-connection according to the inverter grid-connection control strategy, wherein the parameters of the transformer are consistent with those of the transformer of the step-up station of the photovoltaic power station.

Step 108: Superimpose the background harmonics of the busbar harmonic evaluation point of the upper-level regional power grid with the output harmonics of the photovoltaic power station to obtain the final harmonic content of the evaluation point, filter the harmonics of the evaluation point, and obtain the treated photovoltaic power station and the upper-level Harmonic content rate of regional power grid evaluation points after treatment.

Wherein, the final harmonic content rate of the evaluation points includes the background harmonics of the evaluation points of the superior power grid and the same order harmonics of the output harmonics of the photovoltaic power station are superimposed as follows:

Among them, I _h1 is the hth harmonic current of harmonic source 1, I _h2 is the hth harmonic current of harmonic source 2, θ is the difference between the hth harmonic current of harmonic source 1 and harmonic source 2 the phase angle.

The final harmonic content rate of the evaluation points also includes,

Furthermore, when the phase angle is uncertain, the final harmonic content rate is:

Among them, K is the coefficient corresponding to different harmonic orders.

It should be noted that the coefficients corresponding to the different harmonic orders include,

When the harmonic order is three times, the coefficient K corresponding to different harmonic orders is 1.62;

When the harmonic order is fifth, the coefficient K corresponding to different harmonic orders is 1.28;

When the harmonic order is the seventh order, the coefficient K corresponding to different harmonic orders is 0.72;

When the harmonic order is eleventh, the coefficient K corresponding to different harmonic orders is 0.18;

When the harmonic order is thirteenth, the coefficient K corresponding to different harmonic orders is 0.08;

When the harmonic order is ninth or even, the coefficient K corresponding to different harmonic orders is 0.

It should be noted that the filtering includes, after obtaining the harmonics of the evaluation points, filtering the harmonics exceeding the standard when configuring with the SVG method, and then calculating the harmonic content of the evaluation points after configuring the SVG;

Furthermore, if there are still harmonics that exceed the standard and are below the third harmonic, change the SVG configuration filter parameters and placement position, and send out reactive power that can offset the first, second and third harmonics until the harmonic content rate qualified;

Furthermore, if there are still harmonics exceeding the standard, and it is more than the third harmonic, then change the SVG configuration filter parameters and placement position, send out reactive power that can offset the first, second and third harmonics, and absorb the third harmonic Above reactive power, until the harmonic content rate is qualified.

A photovoltaic power station harmonic analysis and control system under a new energy grid, characterized in that it includes a grid model building module, a harmonic model building module, a calculation module and a filtering module,

A power grid model building module, the power grid model building module builds a model of the photovoltaic power station and the upper-level regional power grid according to the size, line, structure, power and harmonic data of the photovoltaic power station;

A harmonic model building module, the harmonic model building module obtains the background harmonics of the upper-level regional power grid busbar and the inverter of the photovoltaic power station, and establishes a photovoltaic power station harmonic model according to the background harmonics;

A calculation module, the calculation module calculates the content rate of the harmonic output of the photovoltaic power plant harmonics in the photovoltaic power plant and the upper-level regional power grid bus harmonic evaluation point according to the photovoltaic power plant harmonic model;

The filtering module, the background harmonics of the upper-level regional grid bus harmonic evaluation points of the filtering module are superimposed on the output harmonics of the photovoltaic power station to obtain the final harmonic content of the evaluation points, and the harmonics of the evaluation points are filtered to obtain Harmonic content rate after treatment of photovoltaic power plants and evaluation points of superior regional power grids. The above-mentioned unit modules can be embedded in or independent of the processor in the computer device in the form of hardware, and can also be stored in the memory of the computer device in the form of software, so that the processor can call and execute the corresponding operations of the above modules.

In one embodiment, a computer device is provided. The computer device may be a terminal, and its internal structure may be as shown in FIG. 3 . The computer device includes a processor, a memory, a communication interface, a display screen and an input device connected through a system bus. Wherein, the processor of the computer device is used to provide calculation and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage medium. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be realized through WIFI, an operator network, NFC (Near Field Communication) or other technologies. When the computer program is executed by a processor, a harmonic analysis and control method of a photovoltaic power station under a new energy grid is realized. The display screen of the computer device may be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device may be a touch layer covered on the display screen, or a button, a trackball or a touch pad provided on the casing of the computer device , and can also be an external keyboard, touchpad, or mouse.

In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored, and when the computer program is executed by a processor, the following steps are implemented:

According to the equipment, lines, structure and harmonic data of the photovoltaic power station and the data of the upper-level power grid, establish the model of the photovoltaic power station and the upper-level regional power grid;

Obtain the background harmonics of the upper-level regional power grid busbar and the inverter of the photovoltaic power station, and establish a harmonic model of the photovoltaic power station according to the background harmonics;

According to the harmonic model of the photovoltaic power station, calculate the harmonic content of the harmonic output of the photovoltaic power station in the photovoltaic power station and the upper-level regional grid bus harmonic evaluation point;

Superimpose the background harmonics of the busbar harmonic evaluation point of the superior regional power grid with the output harmonics of the photovoltaic power station to obtain the final harmonic content of the evaluation point, filter the harmonics of the evaluation point, and obtain the evaluation of the photovoltaic power station and the superior regional power grid after governance Harmonic content rate after point treatment.

Example 2

Referring to Figures 1-3, an embodiment of the present invention provides a photovoltaic power plant harmonic analysis and control method and system under a new energy grid. In order to verify the beneficial effects of the present invention, a scientific demonstration is carried out through comparative experiments.

Table 1 Distinguishing features between traditional technical means and the application of the present invention

It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention without limitation, although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be carried out Modifications or equivalent replacements without departing from the spirit and scope of the technical solution of the present invention shall be covered by the claims of the present invention.

Those skilled in the art should understand that the embodiments of the present application may be provided as methods, systems, or computer program products. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) having computer-usable program code embodied therein. The solutions in the embodiments of the present application can be realized by using various computer languages, for example, the object-oriented programming language Java and the literal translation scripting language JavaScript.

The present application is described with reference to flowcharts and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the present application. It should be understood that each procedure and/or block in the flowchart and/or block diagram, and a combination of procedures and/or blocks in the flowchart and/or block diagram can be realized by computer program instructions. These computer program instructions may be provided to a general purpose computer, special purpose computer, embedded processor, or processor of other programmable data processing equipment to produce a machine such that the instructions executed by the processor of the computer or other programmable data processing equipment produce a An apparatus for realizing the functions specified in one or more procedures of the flowchart and/or one or more blocks of the block diagram.

These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing apparatus to operate in a specific manner, such that the instructions stored in the computer-readable memory produce an article of manufacture comprising instruction means, the instructions The device realizes the function specified in one or more procedures of the flowchart and/or one or more blocks of the block diagram.

These computer program instructions can also be loaded onto a computer or other programmable data processing device, causing a series of operational steps to be performed on the computer or other programmable device to produce a computer-implemented process, thereby The instructions provide steps for implementing the functions specified in the flow diagram procedure or procedures and/or block diagram procedures or blocks.

While preferred embodiments of the present application have been described, additional changes and modifications to these embodiments can be made by those skilled in the art once the basic inventive concept is appreciated. Therefore, the appended claims are intended to be construed to cover the preferred embodiment and all changes and modifications which fall within the scope of the application.

Obviously, those skilled in the art can make various changes and modifications to the application without departing from the spirit and scope of the application. In this way, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalent technologies, the present application is also intended to include these modifications and variations.

Claims (10)

1. A photovoltaic power station harmonic analysis and treatment method under a new energy grid, characterized in that: comprising, According to the equipment, lines, structure and harmonic data of the photovoltaic power station and the data of the upper-level power grid, establish the model of the photovoltaic power station and the upper-level regional power grid; Obtain the background harmonics of the upper-level regional power grid busbar and the inverter of the photovoltaic power station, and establish a harmonic model of the photovoltaic power station according to the background harmonics; According to the harmonic model of the photovoltaic power station, calculate the harmonic content of the harmonic output of the photovoltaic power station in the photovoltaic power station and the upper-level regional grid bus harmonic evaluation point; Superimpose the background harmonics of the busbar harmonic evaluation point of the superior regional power grid with the output harmonics of the photovoltaic power station to obtain the final harmonic content of the evaluation point, filter the harmonics of the evaluation point, and obtain the evaluation of the photovoltaic power station and the superior regional power grid after governance Harmonic content rate after point treatment. 2. The harmonic analysis and treatment method of photovoltaic power plants under the new energy grid as claimed in claim 1, characterized in that: the final harmonic content of the evaluation points includes, The background harmonics of the evaluation points of the superior power grid and the same sub-harmonics of the output harmonics of the photovoltaic power station are superimposed as follows:

Among them, I _h1 is the hth harmonic current of harmonic source 1, I _h2 is the hth harmonic current of harmonic source 2, θ is the difference between the hth harmonic current of harmonic source 1 and harmonic source 2 the phase angle. 3. The harmonic analysis and treatment method of photovoltaic power plants under the new energy grid as claimed in claim 2, characterized in that: the final harmonic content of the evaluation points also includes, When the phase angle is uncertain, the final harmonic content rate is:

Among them, K is the coefficient corresponding to different harmonic orders. 4. The photovoltaic power plant harmonic analysis and treatment method under the new energy grid as claimed in claim 3, characterized in that: the coefficients corresponding to the different harmonic orders include, When the harmonic order is three times, the coefficient K corresponding to different harmonic orders is 1.62; When the harmonic order is fifth, the coefficient K corresponding to different harmonic orders is 1.28; When the harmonic order is the seventh order, the coefficient K corresponding to different harmonic orders is 0.72; When the harmonic order is eleventh, the coefficient K corresponding to different harmonic orders is 0.18; When the harmonic order is thirteenth, the coefficient K corresponding to different harmonic orders is 0.08; When the harmonic order is ninth or even, the coefficient K corresponding to different harmonic orders is 0. 5. The photovoltaic power station harmonic analysis and treatment method under the new energy grid as claimed in claim 4, characterized in that: the photovoltaic power station and the upper-level regional power grid model include a power model and a harmonic model, The power model includes a photovoltaic power station power equivalent model, and the photovoltaic power station power equivalent model includes two parts: a photovoltaic system and a step-up grid-connected system. The photovoltaic system is composed of solar photovoltaic modules connected to inverters, where battery parameters and The control parameters are determined by the actual photovoltaic power station values; The step-up grid-connection system implements classified grid-connection according to the inverter grid-connection control strategy, wherein the parameters of the transformer are consistent with the transformer parameters of the step-up station of the photovoltaic power station. 6. The photovoltaic power station harmonic analysis and treatment method under the new energy grid as claimed in claim 5, characterized in that: the background harmonics of the upper-level regional power grid busbar and the photovoltaic power station inverter include, Before the photovoltaic power station is connected, the harmonic voltage obtained by carrying out the harmonic test on the substation and the power plant at the access point of the photovoltaic power station is used as the background harmonic of the bus bar; When the photovoltaic power station is not connected, the measured harmonic voltage is the harmonic output by the photovoltaic power station, and the inverter harmonic is the harmonic current content of the photovoltaic inverter under 100% operation. The harmonic source model of the harmonic current content rate under the 100% output of the photovoltaic inverter is superimposed on each inverter, and the harmonic model of the photovoltaic power station is established. 7. The photovoltaic power plant harmonic analysis and treatment method under the new energy grid as claimed in claim 6, characterized in that: the filtering includes, After obtaining the harmonics of the evaluation points, filter the harmonics exceeding the standard when configuring with the SVG method, and then calculate the harmonic content of the evaluation points after configuring the SVG; If there is still a harmonic exceeding the standard, and it is below the third harmonic, change the SVG configuration filter parameters and placement position, and send out reactive power that can offset the first, second and third harmonics until the harmonic content rate is qualified; If there are still harmonics exceeding the standard, and it is more than the third harmonic, then change the SVG configuration filter parameters and placement position, send out reactive power that can offset the first, second and third harmonics, and absorb reactive power above the third harmonic Power until the harmonic content rate is qualified. 8. A photovoltaic power plant harmonic analysis and control system under a new energy grid, characterized in that: it includes a power grid model building module, a harmonic model building module, a calculation module and a filtering module, A power grid model building module, the power grid model building module builds a photovoltaic power station and a superior regional power grid model according to the power and harmonic data of the photovoltaic power station; A harmonic model building module, the harmonic model building module obtains the background harmonics of the upper-level regional power grid busbar and the inverter of the photovoltaic power station, and establishes a photovoltaic power station harmonic model according to the background harmonics; A calculation module, the calculation module calculates the content rate of the harmonic output of the photovoltaic power plant harmonics in the photovoltaic power plant and the upper-level regional power grid bus harmonic evaluation point according to the photovoltaic power plant harmonic model; The filtering module, the background harmonics of the upper-level regional grid bus harmonic evaluation points of the filtering module are superimposed on the output harmonics of the photovoltaic power station to obtain the final harmonic content of the evaluation points, and the harmonics of the evaluation points are filtered to obtain Harmonic content rate after treatment of photovoltaic power plants and evaluation points of superior regional power grids. 9. A computer device, comprising a memory and a processor, the memory stores a computer program, wherein the processor implements the method according to any one of claims 1 to 7 when executing the computer program step. 10. A computer-readable storage medium, on which a computer program is stored, characterized in that, when the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

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