Overvoltage treatment method and system for photovoltaic transformer area based on floating neutral wire voltage

Abstract

Disclosed in the present invention are an overvoltage treatment method and system for a photovoltaic transformer area based on a floating neutral wire voltage. The method comprises: a controller collecting a voltage U of a photovoltaic transformer area and a voltage U0 of a neutral point of a transformer; comparing the collected voltage data with a set threshold; on the basis of the comparison result, generating a control instruction for cancellation and compensation; and a neutral wire voltage regulator receiving the instruction, and performing voltage control. A floating neutral wire is introduced between a photovoltaic power supply and a neutral point of a grid-connected transformer, and a neutral wire voltage regulator is arranged at the floating neutral wire. The direction and the amplitude of the neutral wire voltage regulator are adjusted, so that the neutral wire voltage regulator adapts to the voltage problem of a transformer area in different states. Moreover, by adjusting the voltage of the neutral point side of the grid-connected transformer, the voltage of the neutral point of the grid-connected transformer is zero.

Description

Photovoltaic area overvoltage control method and system based on floating neutral voltage Technical Field

[0001] The present invention relates to the technical field of overvoltage control, and in particular to a method and system for overvoltage control in a photovoltaic area based on a floating neutral voltage. Background Art

[0002] The "dual carbon" strategy has provided a new direction for energy development. By limiting carbon emissions from traditional fossil fuels and increasing the proportion of renewable energy generation, photovoltaic power generation has gained widespread adoption in recent years. PV energy, with its wide coverage and convenient installation locations, has become a key driver in achieving the "dual carbon" goals. However, to further increase the proportion of PV power generation in the power grid and ensure electricity security in PV-powered areas, in-depth research and resolution of the current challenges and difficulties facing the PV sector are essential.

[0003] Key issues include voltage fluctuations, limited reactive power control of photovoltaic inverters, and insufficient grid capacity during low-load periods. When photovoltaic power output is excessive, reverse power flows into the substation, causing overvoltage. At night, when photovoltaic power output is insufficient, low voltage conditions occur, further exacerbating voltage fluctuations in the photovoltaic grid. However, low-voltage distribution networks often require inductive reactance to be significantly greater than resistive reactance, rendering traditional decoupling control inapplicable. Reactive power control using photovoltaic inverters, due to its limited capabilities, is unable to effectively offset the voltage rise caused by reverse active power. To maintain grid stability and mitigate voltage fluctuations, current methods primarily regulate the output power of photovoltaic systems through active power control. However, active power control poses a significant constraint, as it can impact the economic benefits of photovoltaic power generation.

[0004] Furthermore, the grounding lead of the distribution transformer may be severely corroded or in poor contact with the grounding conductor, resulting in a high grounding resistance at the transformer's neutral point. Consequently, a ground fault on the low-voltage phase of the photovoltaic station can cause the neutral point's potential to rise relative to ground, leading to a live neutral line. This can endanger the safety of residents and maintenance personnel, and may even cause serious accidents such as fires and electric shocks.

[0005] To address these issues, the present invention proposes a method for overvoltage control in photovoltaic substations based on a floating neutral voltage. This method introduces a floating neutral voltage between the photovoltaic power source and the neutral point of the grid-connected transformer and places a neutral voltage regulator on the floating neutral voltage. By adjusting its direction and magnitude, it can adapt to different substation voltage conditions. Furthermore, by adjusting the neutral voltage of the grid-connected transformer, the neutral voltage of the grid-connected transformer is kept at zero. Summary of the Invention

[0006] In view of the above-mentioned problems, the present invention is proposed.

[0007] Therefore, the technical problem solved by the present invention is that the existing overvoltage control methods have problems such as large power consumption and high cost.

[0008] To solve the above technical problems, the present invention provides the following technical solution: a method for overvoltage control in a photovoltaic area based on floating neutral voltage, comprising:

[0009] The controller collects the voltage U of the photovoltaic area and the voltage U0 of the neutral point of the transformer;

[0010] Compare the collected voltage data with the set threshold;

[0011] Generate control instructions for offset and compensation based on the comparison results;

[0012] The neutral voltage regulator receives the command and performs voltage control.

[0013] As a preferred solution of the photovoltaic area overvoltage control method based on floating neutral line voltage described in the present invention, the overvoltage control device includes a floating neutral line, one end of which is connected to the photovoltaic power source and the other end is connected to the neutral point of the grid-connected transformer;

[0014] A zero line voltage regulator is connected to the neutral point side of the grid-connected transformer of the floating zero line;

[0015] The controller is connected to the neutral voltage regulator and can collect the voltage of the photovoltaic area and the voltage of the neutral point of the transformer, calculate the direction and amplitude of the output voltage of the neutral voltage regulator, and send it to the neutral voltage regulator.

[0016] As a preferred embodiment of the photovoltaic power station overvoltage control method based on a floating neutral line voltage according to the present invention, the overvoltage control device further comprises: the floating neutral line can form a closed loop between the neutral point of the transformer on both sides of the neutral line and the photovoltaic power source, so that the voltage on the neutral line changes with the output of the neutral line voltage regulator, thereby effectively compensating or offsetting the voltage in the power station;

[0017] When the photovoltaic area voltage collected by the controller exceeds the highest threshold or is less than the lowest threshold, the neutral line voltage regulator is controlled to apply a voltage opposite to or the same as that of the photovoltaic power source to the neutral line to achieve voltage offset or compensation for the area.

[0018] As a preferred solution of the photovoltaic area overvoltage control method based on floating neutral voltage according to the present invention, the controller controls the neutral voltage regulator to solve the photovoltaic area overvoltage problem, including the following steps:

[0019] The controller collects the voltage U of the photovoltaic area and compares it with the set maximum threshold U max and the minimum threshold Umin Make comparisons;

[0020] If the voltage U min ≤U≤U max , then return to the step of collecting the photovoltaic area voltage U. If the voltage U is not within the threshold range, proceed to the next step of judgment;

[0021] When the overvoltage in the photovoltaic area is U>U max When , the neutral line voltage regulator is controlled to apply a voltage opposite to the direction of the photovoltaic power supply to the neutral line, and the magnitude is When the low voltage in the photovoltaic area U<U min When the neutral line voltage regulator is controlled, a voltage with the same direction as the photovoltaic power source is applied to the neutral line, and the magnitude is

[0022] As a preferred solution of the photovoltaic area overvoltage control method based on floating neutral line voltage described in the present invention, when the neutral line voltage regulator starts to apply voltage, the controller simultaneously adopts voltage control to offset or compensate for the voltage fluctuation on the floating neutral line.

[0023] As a preferred solution of the photovoltaic area overvoltage control method based on floating neutral line voltage described in the present invention, the neutral line voltage regulator is used to solve the problem of excessively high transformer neutral point voltage and charged neutral line when a grounding fault occurs to a certain low-voltage relative ground on the photovoltaic area side.

[0024] As a preferred solution of the photovoltaic substation overvoltage control method based on floating neutral line voltage described in the present invention, the solution to the problem of excessively high neutral point voltage of the transformer and charged neutral line includes: when the controller detects that the neutral point voltage U0 of the transformer on the substation side is elevated, it immediately sends an instruction to the neutral line voltage regulator to adjust the direction and amplitude of the output voltage;

[0025] When U0>0, the neutral point carries a positive voltage to offset; when U0>0, the neutral point carries a negative voltage to compensate;

[0026] The neutral point voltage is controlled to always be 0, thereby preventing the neutral point potential from rising and avoiding the neutral line from being charged.

[0027] A photovoltaic area overvoltage control system based on floating neutral voltage using the method of the present invention is characterized by:

[0028] The data acquisition unit and controller collect the voltage U of the photovoltaic area and the voltage U0 of the neutral point of the transformer;

[0029] The control unit compares the collected voltage data with the set threshold value; generates control instructions for offset and compensation based on the comparison result; the neutral line voltage regulator receives the instructions and performs voltage control.

[0030] A computer device comprises: a memory and a processor; the memory stores a computer program, wherein the processor implements the steps of any one of the methods of the present invention when executing the computer program.

[0031] A computer-readable storage medium stores a computer program thereon, wherein the computer program, when executed by a processor, implements the steps of any one of the methods of the present invention.

[0032] The present invention provides a method for overvoltage control in photovoltaic substations based on a floating neutral voltage. This method introduces a floating neutral line between the photovoltaic power source and the neutral point of the grid-connected transformer, and installs a neutral line voltage regulator on the floating neutral line. By adjusting its direction and magnitude, it can adapt to different substation voltage conditions. Furthermore, by adjusting the neutral point voltage of the grid-connected transformer, the neutral point voltage of the grid-connected transformer is kept at zero. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] To more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive effort. Among them:

[0034] FIG1 is an overall flow chart of a photovoltaic area overvoltage control method based on floating neutral voltage provided by a first embodiment of the present invention;

[0035] FIG2 is a schematic diagram of a photovoltaic area structure with a floating neutral voltage in a photovoltaic area overvoltage control method based on a floating neutral voltage provided by a first embodiment of the present invention;

[0036] 3 is a schematic diagram of a photovoltaic area circuit with a floating neutral voltage according to a photovoltaic area overvoltage control method based on a floating neutral voltage provided by a first embodiment of the present invention;

[0037] FIG4 is a floating neutral line voltage regulation voltage vector diagram of a photovoltaic area overvoltage control method based on a floating neutral line voltage provided by a second embodiment of the present invention;

[0038] 5 is a flowchart of the neutral line voltage regulator operation of the photovoltaic area overvoltage control method based on floating neutral line voltage provided by the second embodiment of the present invention;

[0039] 6 is a schematic diagram of grounding on the outgoing line side of a phase line in a photovoltaic area according to a method for overvoltage control in a photovoltaic area based on a floating neutral voltage provided by a third embodiment of the present invention;

[0040] FIG7 is a flow chart of transformer neutral point voltage control in a photovoltaic area overvoltage control method based on floating neutral line voltage according to a third embodiment of the present invention. DETAILED DESCRIPTION

[0041] To make the above-mentioned objects, features, and advantages of the present invention more clearly understood, the following detailed description of the specific embodiments of the present invention is given in conjunction with the accompanying drawings. It is obvious that the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in this field without creative work should fall within the scope of protection of the present invention.

[0042] Example 1

[0043] 1 to 3 , an embodiment of the present invention provides a photovoltaic area overvoltage control device based on a floating neutral voltage, including:

[0044] Specifically, as shown in Figures 2 and 3, the photovoltaic area structure and circuit diagram of the floating neutral voltage. The photovoltaic area overvoltage control based on the floating neutral voltage includes the following three additional devices:

[0045] The floating neutral line has one end connected to the photovoltaic power source and the other end connected to the neutral point of the grid-connected transformer.

[0046] A zero line voltage regulator is connected to the neutral point side of the grid-connected transformer of the floating zero line.

[0047] The controller is connected to the neutral voltage regulator and can collect the voltage of the photovoltaic area and the voltage of the neutral point of the transformer, calculate the direction and amplitude of the output voltage of the neutral voltage regulator, and send it to the neutral voltage regulator.

[0048] Furthermore, the characteristics of the floating neutral voltage are used to actively control overvoltage (or undervoltage) issues in the photovoltaic power station. The floating neutral voltage characteristic forms a closed loop between the neutral point of the transformer and the photovoltaic power source on both sides of the neutral line, so that the voltage on the neutral line changes with the output of the neutral line voltage regulator, thereby effectively compensating or offsetting the voltage in the power station. When the photovoltaic power station voltage collected by the controller exceeds the maximum threshold or is less than the minimum threshold, the neutral line voltage regulator is controlled to apply a voltage to the neutral line that is opposite to or the same as that of the photovoltaic power source to offset or compensate the voltage in the power station.

[0049] Example 2

[0050] 4 and 5 , an embodiment of the present invention provides a method for overvoltage control in a photovoltaic area based on a floating neutral voltage, including:

[0051] The controller controls the neutral voltage regulator to solve the overvoltage problem in the photovoltaic area:

[0052] S1: The controller collects the voltage U of the photovoltaic area and compares it with the set maximum threshold U max and the minimum threshold U min Make a comparison.

[0053] S2: If the voltage U of the photovoltaic area is within the threshold range (U min ≤U≤U max ), then return to S1, if the voltage U is not within the threshold range, proceed to the next step S3.

[0054] S3: When the photovoltaic area overvoltage U>U max When , the neutral line voltage regulator is controlled to apply a voltage opposite to the direction of the photovoltaic power supply to the neutral line, and the magnitude is When the low voltage in the photovoltaic area U<U min When the neutral line voltage regulator is controlled, a voltage with the same direction as the photovoltaic power source is applied to the neutral line, and the magnitude is

[0055] Further, the floating neutral line voltage vector diagram, where U A '、U B '、U C ' is the voltage regulation voltage of floating neutral line, when the three-phase voltage U A 、U B 、U C When fluctuation occurs, the U A '、U B '、U C The magnitude and direction of the voltage regulator can be adjusted to suppress overvoltage in the photovoltaic area and compensate for undervoltage in the photovoltaic area, as shown in Figure 4. The steps of controlling the neutral voltage regulator to solve the overvoltage (lowvoltage) problem in the photovoltaic area are shown in Figure 5.

[0056] Example 3

[0057] 6 and 7 , an embodiment of the present invention provides a method for overvoltage control in a photovoltaic area based on a floating neutral voltage, including:

[0058] Specifically, as shown in FIG7 , the transformer neutral point voltage control flow chart. The controller controls the neutral line voltage regulator to solve the neutral line live problem, including the following steps:

[0059] S1: The controller collects the voltage U0 of the neutral point of the transformer and compares it with the set zero voltage threshold.

[0060] S2: When the controller determines that the voltage at the neutral point of the transformer is zero or within the threshold range, it returns to S1; if the voltage at the neutral point of the transformer is not zero or within the threshold range, it proceeds to S3.

[0061] S3: The controller calculates the voltage of the neutral voltage regulator required to offset or compensate for the transformer neutral point voltage being zero, and adjusts its output voltage to ensure that the transformer neutral point voltage is zero.

[0062] Furthermore, when the controller detects that the neutral point voltage U0 of the transformer on the substation side is raised, it immediately sends an instruction to the neutral line voltage regulator to adjust the direction and amplitude of the output voltage; when U0>0, the neutral point carries a positive voltage for offset; when U0>0, the neutral point carries a negative voltage for compensation; the neutral point voltage is controlled to always be 0, thereby preventing the neutral point potential from rising and avoiding the neutral line from being energized.

[0063] It should be noted that when the controller controls the neutral line voltage regulator to solve the problem of neutral line being charged, the method of voltage offset and compensation is similar to the steps for solving the overvoltage problem in the photovoltaic area.

[0064] When the neutral point voltage U0 of the transformer is positive, the zero line voltage regulator is controlled to apply a voltage opposite to the neutral point voltage of the transformer to the zero line to offset it, and the magnitude is ΔU 01 =|U0|. When the low voltage U0 in the photovoltaic area is negative, the zero line voltage regulator is controlled to apply a voltage in the same direction as the neutral point of the transformer to the zero line for compensation, and the magnitude is ΔU 01 =|U0|; here, because it is negatively charged, |ΔU 01 |A positive value and input in the same direction can ensure that the neutral point is not energized.

[0065] It is also important to note that the controller controls the neutral voltage regulator to solve the problem of excessively high neutral voltage and live neutral voltage of the transformer when a ground fault occurs on the low-voltage phase of the photovoltaic station side, thus avoiding the impact on the power grid. As shown in Figure 6, it is a schematic diagram of the grounding side of a phase line in the station. If a ground fault occurs on phase a of the station side, the fault current I a The phase line, the earth and the grounding resistance form a loop. Due to the grounding resistance R f Equivalent resistance to earth R s Not zero, fault current I a The grounding resistance R f and the equivalent resistance R s The voltage drop will cause the neutral point to increase its potential to the ground, which will cause the neutral line to be charged. The voltage on the neutral line is: U0=I a ·R s

[0066] Where U0 is the voltage between the neutral line and the ground.

[0067] Because the floating neutral is connected to the transformer's neutral point, the issue of neutral-line liveness can be addressed using a floating neutral voltage regulator. Once the controller detects a rise in the transformer's neutral-point voltage, it immediately sends a command to the neutral voltage regulator to adjust the direction and amplitude of its output voltage. This offsets or compensates for the transformer's neutral-point voltage rise caused by the fault, preventing a rise in neutral-point potential and thus avoiding neutral-line liveness.

[0068] On the other hand, this embodiment also provides a photovoltaic area overvoltage control system based on floating neutral voltage, which includes:

[0069] The data acquisition unit (DCU) and the controller collect the PV grid voltage (U) and the transformer neutral point voltage (U0). The control unit compares the collected voltage data with the set thresholds and, based on the comparison results, generates control instructions for offset and compensation. The neutral voltage regulator receives these instructions and performs voltage control.

[0070] If the above functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0071] The logic and / or steps represented in the flowcharts or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing the logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (e.g., a computer-based system, a system including a processor, or other system that can fetch and execute instructions from an instruction execution system, apparatus, or device). For purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by, or in conjunction with, an instruction execution system, apparatus, or device.

[0072] More specific examples (a non-exhaustive list) of computer-readable media include the following: an electrical connection with one or more wires (electronic devices), a portable computer disk cartridge (magnetic devices), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), a fiber optic device, and a portable compact disc read-only memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, deciphering, or processing in another suitable manner as necessary, and then stored in a computer memory.

[0073] It should be understood that various parts of the present invention can be implemented using hardware, software, firmware, or a combination thereof. In the above-described embodiments, multiple steps or methods can be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented using hardware, as in another embodiment, any one of the following technologies known in the art or a combination thereof can be used: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application-specific integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0074] Example 4

[0075] The following is an embodiment of the present invention, which provides a method for overvoltage control in a photovoltaic area based on a floating neutral voltage. In order to verify the beneficial effects of the present invention, scientific demonstration is carried out through economic benefit calculation and simulation experiments.

[0076] By comparing 100 experiments before and after the present invention, several parameters are obtained as shown in Table 1.

[0077] Table 1 Data comparison table

[0078] The present invention reduces the number of overvoltage events per day from 10 to 2. This demonstrates a significant improvement in the system's efficiency in overvoltage management, which is of great significance to the stable operation of equipment and the power grid. After adopting the present invention, the highest voltage peak in the system was reduced from 260V to 240V. This reduction helps prevent overload and damage to electrical equipment, extend equipment life, and reduce maintenance costs. The present invention reduces voltage fluctuations at the transformer neutral point from ±5% to ±1%, significantly improving voltage stability. This is crucial for maintaining the overall stability and safe operation of the power grid. The present invention can respond to power grid faults within 100 milliseconds, significantly reducing the response time of 500 milliseconds when not adopting the present invention. This rapid response capability is crucial for preventing or mitigating the impact of power grid faults. Through more effective voltage management, the present invention reduces the annual equipment damage rate from 5% to 1%, which means reduced repair and replacement costs, thereby improving economic benefits. By improving voltage management, the present invention improves system energy efficiency by 3%, reduces energy waste, and improves overall energy efficiency. In summary, this invention, through its innovative voltage management method, improves system energy efficiency, reduces operating costs, and enhances responsiveness to grid faults while ensuring voltage stability in the photovoltaic area. These advantages make this invention valuable for applications in power systems and photovoltaic power generation.

[0079] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A photovoltaic area overvoltage control method based on floating neutral voltage, characterized in that: include: The controller collects the voltage U of the photovoltaic area and the voltage U0 of the neutral point of the transformer; Compare the collected voltage data with the set threshold value; Generate control instructions for offset and compensation according to the comparison results; The neutral voltage regulator receives the command and performs voltage control.

2. The photovoltaic area overvoltage control method based on floating neutral voltage as claimed in claim 1 is characterized in that: The overvoltage control device includes a floating neutral line, one end of which is connected to the photovoltaic power source and the other end is connected to the neutral point of the grid-connected transformer; A zero line voltage regulator connected to the neutral point side of the grid-connected transformer of the floating zero line; The controller is connected to the neutral line voltage regulator, and can collect the voltage of the photovoltaic area and the voltage of the neutral point of the transformer, calculate the direction and amplitude of the output voltage of the neutral line voltage regulator, and send it to the neutral line voltage regulator.

3. The photovoltaic area overvoltage control method based on floating neutral voltage as claimed in claim 2 is characterized by: The overvoltage control device also includes that the floating neutral line can form a closed loop between the neutral point of the transformer and the photovoltaic power source on both sides of the neutral line, so that the voltage on the neutral line changes with the output of the neutral line voltage regulator, thereby effectively compensating or offsetting the voltage of the station area; When the photovoltaic area voltage collected by the controller exceeds the highest threshold or is less than the lowest threshold, the neutral line voltage regulator is controlled to apply a voltage opposite to or the same as that of the photovoltaic power source to the neutral line to achieve voltage offset or compensation for the area.

4. The photovoltaic area overvoltage control method based on floating neutral voltage as claimed in claim 3 is characterized by: The controller controls the neutral voltage regulator to solve the overvoltage problem in the photovoltaic area, including: The controller collects the voltage U of the photovoltaic area and compares it with the set maximum threshold U max and the minimum threshold U min Make comparisons; If the voltage U min ≤U≤U max , then return to the step of collecting the photovoltaic area voltage U. If the voltage U does not meet the threshold range, proceed to the next step of judgment; When the photovoltaic area overvoltage U>U max When , the neutral line voltage regulator is controlled to apply a voltage opposite to the photovoltaic power source to the neutral line, and the magnitude is When the low voltage in the photovoltaic area U<U min When , the neutral line voltage regulator is controlled to apply a voltage in the same direction as the photovoltaic power source to the neutral line, and the magnitude is 5. The photovoltaic area overvoltage control method based on floating neutral voltage as claimed in claim 4 is characterized in that: When the neutral line voltage regulator starts to apply voltage, the controller simultaneously takes voltage control to offset or compensate for voltage fluctuations on the floating neutral line.

6. The photovoltaic area overvoltage control method based on floating neutral voltage as claimed in claim 5, characterized in that: The neutral line voltage regulator can solve the problem of excessively high voltage at the neutral point of the transformer and energized neutral line when a grounding fault occurs to a certain low-voltage relative ground on the photovoltaic station side.

7. The photovoltaic area overvoltage control method based on floating neutral voltage as claimed in claim 6 is characterized by: The solution to the problem of excessively high neutral point voltage of the transformer and energized neutral line includes: when the controller detects that the neutral point voltage U0 of the transformer on the substation side is raised, it immediately sends a command to the neutral line voltage regulator to adjust the direction and amplitude of the output voltage; When U0>0, the neutral point carries positive voltage for offset; when U0>0, the neutral point carries negative voltage for compensation; The neutral point voltage is controlled to be always 0, thereby preventing the neutral point potential from rising and avoiding the neutral line from being charged.

8. A photovoltaic area overvoltage control system based on floating neutral voltage using the method according to any one of claims 1 to 7, characterized in that: The data acquisition unit and the controller collect the voltage U of the photovoltaic area and the voltage U0 of the neutral point of the transformer; A control unit compares the collected voltage data with a set threshold value; According to the comparison result, control instructions for offset and compensation are generated; the neutral line voltage regulator receives the instructions and performs voltage control.

9. A computer device comprising: Memory and processor; The memory stores a computer program, characterized in that: when the processor executes the computer program, the steps of the photovoltaic area overvoltage control method based on floating neutral line voltage are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of a method for overvoltage control in a photovoltaic area based on a floating neutral voltage are implemented.

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