Photovoltaic power station anti-islanding protection method, device and equipment and storage medium

Abstract

The invention provides a photovoltaic power station anti-islanding protection method, device and equipment and a storage medium, and relates to the technical field of power system protection. The method comprises the following steps: controlling an inverter of a photovoltaic power station to continuously inject a disturbance signal into a photovoltaic grid-connected system, and monitoring power measurement data of a grid-connected point after the disturbance signal is injected; when the electric power measurement data exceed a preset threshold range, determining that the electric power measurement data is abnormal; determining an abnormal duration in combination with historical power measurement data; and if the abnormal duration is greater than the abnormal duration threshold, the grid-connected switch is controlled to be switched off, and anti-islanding protection of the photovoltaic power station is realized. According to the method, the disturbance signal is actively injected, the detection sensitivity is remarkably improved, the abnormal duration is analyzed in combination with historical data, the islanding effect and instantaneous fluctuation are effectively distinguished, misjudgment is reduced, the islanding detection precision is remarkably improved, it is ensured that the islanding effect can be recognized and processed timely and accurately, and the islanding detection efficiency is improved. And the safety and the reliability of the operation of the photovoltaic power station are further enhanced.

Description

Technical Field

[0001] The present application relates to the technical field of power system protection, and in particular to a photovoltaic power station anti-islanding protection method, device, equipment and storage medium. Background Art

[0002] In recent years, with the continuous growth of global demand for renewable energy, the photovoltaic power generation industry has developed rapidly. In photovoltaic power generation systems, the safety and stability of grid-connected photovoltaic power stations are particularly important. However, in the event of a grid failure or abnormality, an islanding effect may occur, that is, when the grid stops supplying power due to a failure or power outage, the photovoltaic power station or other distributed power sources continue to supply power to the local grid. The islanding effect may not only cause the voltage and frequency of the grid to become unstable, affecting the power supply quality, but also pose a serious safety threat to the maintenance personnel of the power system. Therefore, how to effectively carry out anti-islanding protection of photovoltaic power stations has become a core issue that needs to be solved urgently.

[0003] In the related art, whether the islanding effect occurs is usually detected by monitoring the change of the grid voltage or frequency, but there is a problem of low detection accuracy. Summary of the invention

[0004] The present application provides a photovoltaic power station anti-islanding protection method, device, equipment and storage medium, which are used to improve the problem of low detection accuracy of the islanding effect.

[0005] In a first aspect, the present application provides a photovoltaic power station anti-islanding protection method, comprising:

[0006] Control the inverter of the photovoltaic power station to continuously inject disturbance signals into the photovoltaic grid-connected system;

[0007] After the disturbance signal is injected, the power measurement data of the grid connection point in the photovoltaic grid-connected system is monitored;

[0008] When the power measurement data exceeds a preset threshold range, determining that the power measurement data is abnormal;

[0009] Determine the duration of abnormality in the power measurement data based on historical power measurement data within a recent preset time period;

[0010] When the duration of the abnormality is greater than the abnormality duration threshold, the grid-connected switch in the photovoltaic grid-connected system is controlled to be disconnected to perform anti-islanding protection on the photovoltaic power station.

[0011] In a possible implementation, the power measurement data includes voltage and frequency, the threshold range includes a voltage threshold range and a frequency threshold range, and when the power measurement data exceeds a preset threshold range, it is determined that the power measurement data is abnormal, including: if the voltage exceeds the voltage threshold range, and / or the frequency exceeds the frequency threshold range, it is determined that the power measurement data is abnormal.

[0012] In a possible implementation, when the duration of the abnormality is greater than the abnormality duration threshold, the grid-connected switch in the photovoltaic grid-connected system is controlled to be disconnected, including: if the duration of the first abnormality corresponding to the voltage is greater than the first abnormality duration threshold, and / or the duration of the second abnormality corresponding to the frequency is greater than the second abnormality duration threshold, then the grid-connected switch in the photovoltaic grid-connected system is controlled to be disconnected.

[0013] In a possible implementation, the photovoltaic power station anti-islanding protection method further includes: when the power measurement data meets a preset threshold range, determining that the power measurement data is normal; determining the abnormality-free duration of the power measurement data based on historical power measurement data within a recent preset time period; when the abnormality-free duration is greater than a normal time threshold, controlling the grid-connected switch in the photovoltaic grid-connected system to close, so as to achieve automatic grid connection of the photovoltaic power station.

[0014] In a possible implementation, when the duration without abnormality is greater than the normal duration threshold, the grid-connected switch in the photovoltaic grid-connected system is controlled to close, including: when the duration without abnormality is greater than the normal duration threshold, obtaining the bus voltage on the grid side of the photovoltaic grid-connected system; comparing the voltage of the grid-connected point with the bus voltage; if the voltage of the grid-connected point is consistent with the bus voltage, controlling the grid-connected switch in the photovoltaic grid-connected system to close.

[0015] In a possible implementation, the photovoltaic power station anti-islanding protection method also includes at least one of the following: reporting power measurement data to a power management system; when the duration of an abnormality is greater than an abnormal duration threshold, reporting fault alarm information to the power management system, the fault alarm information including the occurrence time of the islanding effect and the disconnection time of the grid-connected switch; when the duration of no abnormality is greater than a normal duration threshold, reporting fault relief information to the power management system, the fault relief information including the relief time of the islanding effect and the closing time of the grid-connected switch.

[0016] In a possible implementation, the photovoltaic power station anti-islanding protection method further includes: storing protection action data when the grid-connected switch in the photovoltaic grid-connected system is triggered to disconnect or close, the protection action data is used for retrospective analysis of the islanding effect and evaluation of the protection effect of the photovoltaic grid-connected system, and the protection action data includes the moment when the grid-connected switch is triggered to disconnect or close, the power measurement data at that moment, and the historical power measurement data within a preset time period before the trigger.

[0017] In a second aspect, the present application provides a photovoltaic power station anti-islanding protection device, comprising:

[0018] The control and protection module is used to control the inverter of the photovoltaic power station to continuously inject disturbance signals into the photovoltaic grid-connected system;

[0019] A data acquisition module, used to monitor the power measurement data of the grid connection point in the photovoltaic grid-connected system after the disturbance signal is injected;

[0020] The data processing module is used to determine that the power measurement data is abnormal when the power measurement data exceeds a preset threshold range; and determine the duration of the abnormality of the power measurement data based on the historical power measurement data within a recent preset time period;

[0021] The control and protection module is also used to control the grid-connected switch in the photovoltaic grid-connected system to disconnect when the abnormality lasts longer than the abnormality duration threshold, so as to provide anti-islanding protection for the photovoltaic power station.

[0022] In a possible implementation, the photovoltaic power station anti-islanding protection device further includes: a data storage and fault analysis module and a communication module, wherein:

[0023] The data storage and fault analysis module is used to store the protection action data when the grid-connected switch in the photovoltaic grid-connected system is triggered to disconnect or close. The protection action data is used for retrospective analysis of the islanding effect and evaluation of the protection effect of the photovoltaic grid-connected system. The protection action data includes the time when the grid-connected switch is triggered to disconnect or close, the power measurement data at that time, and the historical power measurement data within the most recent preset time before the trigger.

[0024] A communication module, used for at least one of the following: reporting power measurement data to a power management system; reporting fault alarm information to the power management system when the duration of an abnormality is greater than an abnormal duration threshold, the fault alarm information includes the occurrence time of the islanding effect and the disconnection time of the grid-connected switch; reporting fault relief information to the power management system when the duration of no abnormality is greater than a normal duration threshold, the fault relief information includes the relief time of the islanding effect and the closing time of the grid-connected switch.

[0025] In a third aspect, the present application provides an electronic device, comprising: a processor, and a memory communicatively connected to the processor;

[0026] Memory for storing computer-executable instructions;

[0027] A processor is used to execute computer-executable instructions stored in the memory to implement the method described in any one of the first aspects.

[0028] In a fourth aspect, the present application provides a computer-readable storage medium, in which computer-executable instructions are stored. When the computer-executable instructions are executed, they are used to implement any method described in the first aspect.

[0029] In a fifth aspect, the present application provides a computer program product, including a computer program, which implements the method described in any one of the first aspects when executed.

[0030] The anti-islanding protection method, device, equipment and storage medium provided by this application, wherein the method includes: controlling the inverter of the photovoltaic power station to continuously inject disturbance signals into the photovoltaic grid-connected system, and after injecting the disturbance signals, monitoring the power measurement data of the grid connection point in the photovoltaic grid-connected system; when the power measurement data exceeds the preset threshold range, determining that the power measurement data is abnormal; determining the abnormal duration of the power measurement data according to the historical power measurement data within the most recent preset duration; when the abnormal duration is greater than the abnormal duration threshold, controlling the grid connection switch in the photovoltaic grid-connected system to disconnect, so as to perform anti-islanding protection on the photovoltaic power station. During this process, by actively injecting disturbance signals into the grid-connected system, it breaks through the dependence of traditional passive detection methods on the natural fluctuations of voltage and frequency, and significantly improves the detection sensitivity; by real-time monitoring the power measurement data of the grid connection point and comparing it with the preset threshold range, abnormal situations can be quickly identified, effectively reducing the occurrence of misjudgment or missed judgment; at the same time, by combining the historical power measurement data to determine the abnormal duration and judging whether it is an islanding effect based on the abnormal duration, the detection accuracy is further improved, reducing the misjudgment caused by instantaneous fluctuations, thereby significantly improving the accuracy of islanding detection and ensuring that the islanding effect can be detected in time; in addition, after determining the existence of the islanding effect, the grid connection switch is automatically controlled to disconnect, ensuring that the islanding effect can be processed in time, and on the premise of ensuring the safety of the photovoltaic grid-connected system, reducing the number of trips caused by misjudgment as much as possible, significantly improving the safety and stability of the photovoltaic power station, and at the same time reducing the damage risk of the islanding effect to the power grid and equipment. Description of the Drawings

[0031] The drawings here are incorporated into the specification and form a part of this specification, showing the embodiments in line with this application, and are used together with the specification to explain the principles of this application.

[0032] Figure 1 It is a schematic flowchart of the anti-islanding protection method for a photovoltaic power station provided by an exemplary embodiment of this application;

[0033] Figure 2 It is another schematic flowchart of the anti-islanding protection method for a photovoltaic power station provided by an exemplary embodiment of this application;

[0034] Figure 3 It is a schematic structural diagram of the anti-islanding protection device for a photovoltaic power station provided by an exemplary embodiment of this application;

[0035] Figure 4 It is another schematic structural diagram of the anti-islanding protection device for a photovoltaic power station provided by an exemplary embodiment of this application;

[0036] Figure 5 It is a schematic architecture diagram of the anti-islanding protection device for a photovoltaic power station provided by an exemplary embodiment of this application;

[0037] Figure 6 Schematic diagram of the structure of the electronic device provided for the exemplary embodiment of the present application.

[0038] Through the above-mentioned drawings, specific embodiments of the present application have been shown, and there will be more detailed descriptions hereinafter. These drawings and textual descriptions are not intended to limit the scope of the concept of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. Detailed implementation manners

[0039] Here, the exemplary embodiments will be described in detail, and the examples are shown in the drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementation manners described in the following exemplary embodiments do not represent all implementation manners consistent with the present application. On the contrary, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0040] The terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects and do not necessarily have to be used to describe a specific order or sequence. It should be understood that such used data can be interchanged under appropriate circumstances so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, system, product, or device that includes a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, products, or devices.

[0041] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data for analysis, stored data, displayed data, etc.) involved in the present application are all information and data authorized by the user or fully authorized by all parties, and the collection, use, and processing of relevant data need to comply with relevant laws, regulations, and standards, and corresponding operation entrances are provided for the user to select authorization or rejection.

[0042] In the prior art, there are obvious limitations in detecting whether an islanding effect occurs by monitoring the changes in the grid voltage or frequency, especially in terms of detection accuracy. Since this method relies on the natural fluctuations of voltage or frequency, when the power of the grid and the photovoltaic power station is close to balance, it is difficult to accurately judge the islanding effect only by monitoring the changes in the grid voltage or frequency, and there is a risk of misjudgment or missed judgment, usually resulting in a lag in response, making the islanding duration too long and affecting the power supply quality and power supply safety.

[0043] To solve the above problems, the embodiments of the present application provide a method for anti-islanding protection of a photovoltaic power station. By adopting an active detection method and using frequency disturbance and voltage disturbance technologies, a disturbance signal is continuously injected into the photovoltaic grid-connected system to slightly disturb the frequency and voltage of the system. By monitoring the power measurement data at the grid connection point in the photovoltaic grid-connected system after the disturbance and combining the historical power measurement data, the abnormal duration of the power measurement data is determined to identify the islanding effect. This not only improves the accuracy of islanding effect detection, reduces false positives and false negatives, but also significantly improves the response speed, enabling timely response within a very short time after the occurrence of the islanding effect. On the premise of ensuring the safety of the photovoltaic grid-connected system, the number of trips caused by false positives is minimized as much as possible, significantly enhancing the safety and stability of the photovoltaic power station, and at the same time reducing the risk of damage to the power grid and equipment caused by the islanding effect.

[0044] The following uses specific embodiments to elaborate in detail on the technical solutions of the present application and how the technical solutions of the present application solve the above technical problems. These several specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0045] Figure 1 It is a schematic flowchart of a method for anti-islanding protection of a photovoltaic power station provided by an exemplary embodiment of the present application. As Figure 1 shown, the method for anti-islanding protection of the photovoltaic power station includes the following steps:

[0046] S101. Control the inverter of the photovoltaic power station to continuously inject a disturbance signal into the photovoltaic grid-connected system.

[0047] Among them, a photovoltaic power station is a power generation system that converts solar energy into electrical energy using the photovoltaic effect, usually consisting of photovoltaic modules, inverters, support systems, combiner boxes, transformers, and monitoring systems, etc.; an inverter refers to a device that converts the direct current generated by photovoltaic modules into alternating current and is the core component for the photovoltaic power station to be grid-connected; a disturbance signal refers to a small frequency or voltage change signal injected for detecting the grid state.

[0048] Exemplarily, an active detection method is adopted to control the inverter of the photovoltaic power station to generate a disturbance signal and superimpose it on the normal output voltage or frequency. Specifically, based on the rated frequency (such as 50 Hz), a small frequency jitter of ±0.1 Hz to ±0.5 Hz is injected. For example, the output frequency is adjusted from 50.0 Hz to 50.2 Hz and then restored to 50.0 Hz after a period of time; or, based on the rated voltage, a small voltage adjustment of ±0.5% to ±1% is injected. For example, the output voltage is adjusted from 220 V to 222 V and then restored to 220 V after a period of time. Among them, the injection of the disturbance signal is periodic, for example, injected once every 5 seconds to ensure continuous monitoring of the state of the photovoltaic grid-connected system.

[0049] S102. After injecting the disturbance signal, monitor the power measurement data at the grid connection point of the photovoltaic grid-connected system.

[0050] Exemplarily, after injecting the disturbance signal, the power measurement data at the grid connection point is monitored in real time through a transformer installed at the grid connection point, such as a potential transformer (PT) or a current transformer (CT).

[0051] S103. When the power measurement data exceeds the preset threshold range, it is determined that the power measurement data is abnormal.

[0052] Among them, the preset threshold range can be determined comprehensively based on relevant grid standards, equipment characteristics (such as the tolerance of the inverter or transformer of the photovoltaic power station), safety margins, and actual operation experience, etc., to ensure the reliability and applicability of the detection. Therefore, the setting of the preset threshold range is not limited here.

[0053] Correspondingly, considering that usually, the power grid, as a strong grid, has a strong anti-disturbance ability and can effectively suppress the small adjustments (such as frequency or voltage disturbances) injected by the inverter. Therefore, the power measurement data at the grid connection point of the photovoltaic grid-connected system is usually not affected. However, when the islanding effect occurs, that is, after the external power grid is disconnected, only the local load and the inverter are running. Due to the lack of the suppression effect of the power grid, the disturbance signal injected by the inverter will cause significant changes in the power measurement data at the grid connection point. This response characteristic is a typical manifestation of the islanding effect. Based on this, by monitoring the power measurement data in real time and judging whether it exceeds the preset threshold range, if the data exceeds the threshold range, it can be determined that the power measurement data is abnormal.

[0054] S104. Determine the abnormal duration of the power measurement data according to the historical power measurement data within the recently preset duration.

[0055] Exemplarily, the power measurement data of the grid connection point is stored in real time, and the acquisition time of the power measurement data is recorded; correspondingly, when it is determined that the current power measurement data is abnormal, the historical power measurement data within the most recent preset duration, such as 5 minutes, stored locally is obtained, and the duration of the abnormal state is calculated in combination with the historical power measurement data. For example, if the power measurement data exceeds the preset threshold range for 1 minute within 5 minutes, the abnormal duration is 1 minute; if the power measurement data exceeds the preset threshold range for 30 seconds within 5 minutes, the abnormal duration is 30 seconds.

[0056] S105. When the abnormal duration is greater than the abnormal duration threshold, control the grid connection switch in the photovoltaic grid connection system to disconnect, so as to perform anti-islanding protection on the photovoltaic power station.

[0057] Exemplarily, when the abnormal duration exceeds the preset abnormal duration threshold, such as 1 minute, it is determined that an islanding effect has occurred, and the grid connection switch in the photovoltaic grid connection system is immediately controlled to disconnect. By timely cutting off the output of the photovoltaic power station under the islanding effect, anti-islanding protection of the photovoltaic power station is realized, ensuring safe isolation and preventing the spread of the islanding effect.

[0058] The anti-islanding protection method for a photovoltaic power station provided by the embodiments of the present application breaks through the dependence on the natural fluctuations of voltage and frequency of traditional passive detection methods by actively injecting disturbance signals into the grid connection system, significantly improving the detection sensitivity; by real-time monitoring the power measurement data of the grid connection point and comparing it with the preset threshold range, abnormal conditions can be quickly identified, effectively reducing the occurrence of misjudgment or missed judgment; at the same time, the abnormal duration is determined in combination with the historical power measurement data, and whether it is an islanding effect is judged based on the abnormal duration, further improving the detection accuracy and reducing misjudgment caused by instantaneous fluctuations, thereby significantly improving the accuracy of island detection and ensuring that the islanding effect can be detected in time; in addition, after determining the existence of the islanding effect, the grid connection switch is automatically controlled to disconnect, ensuring that the islanding effect can be processed in time, and on the premise of ensuring the safety of the photovoltaic grid connection system, reducing the number of trips caused by misjudgment as much as possible, significantly improving the safety and stability of the photovoltaic power station, and at the same time reducing the damage risk of the islanding effect to the power grid and equipment.

[0059] In some embodiments, the power measurement data includes voltage and frequency, the threshold range includes a voltage threshold range and a frequency threshold range, and when the power measurement data exceeds the preset threshold range, determining that the power measurement data is abnormal includes: if the voltage exceeds the voltage threshold range, and / or the frequency exceeds the frequency threshold range, it is determined that the power measurement data is abnormal.

[0060] Exemplarily, it is assumed that the voltage threshold range is 210V - 230V and the frequency threshold range is 49.5Hz - 50.5Hz.

[0061] Correspondingly, in one implementation, if the voltage is lower than 210V or exceeds 230V, it is determined that the power measurement data is abnormal.

[0062] In another implementation, if the frequency is lower than 49.5Hz or exceeds 50.5Hz, it is determined that the power measurement data is abnormal.

[0063] In yet another implementation, if the voltage is lower than 210V or exceeds 230V, and the frequency is lower than 49.5Hz or exceeds 50.5Hz, it is determined that the power measurement data is abnormal.

[0064] In some embodiments, when the abnormal duration is greater than the abnormal duration threshold, the grid-connected switch in the photovoltaic grid-connected system is controlled to disconnect, including: if the first abnormal duration corresponding to the voltage is greater than the first abnormal duration threshold, and / or, the second abnormal duration corresponding to the frequency is greater than the second abnormal duration threshold, then the grid-connected switch in the photovoltaic grid-connected system is controlled to disconnect.

[0065] Exemplarily, it is assumed that the first abnormal duration threshold is 1 minute and the second abnormal duration threshold is 30 seconds.

[0066] Correspondingly, in one implementation, if the first abnormal duration corresponding to the voltage is greater than 1 minute, it is determined that islanding occurs, and a tripping instruction is immediately sent to the grid-connected switch in the photovoltaic grid-connected system, and this tripping instruction is used to control the grid-connected switch in the photovoltaic grid-connected system to disconnect.

[0067] In another implementation, if the second abnormal duration corresponding to the frequency is greater than 30 seconds, it is determined that islanding occurs, and a tripping instruction is immediately sent to the grid-connected switch in the photovoltaic grid-connected system, and this tripping instruction is used to control the grid-connected switch in the photovoltaic grid-connected system to disconnect.

[0068] In yet another implementation, if the first abnormal duration corresponding to the voltage is greater than 1 minute, and the second abnormal duration corresponding to the frequency is greater than 30 seconds, it is determined that islanding occurs, and a tripping instruction is immediately sent to the grid-connected switch in the photovoltaic grid-connected system, and this tripping instruction is used to control the grid-connected switch in the photovoltaic grid-connected system to disconnect.

[0069] It can be understood that the above voltage threshold range of 210V - 230V, frequency threshold range of 49.5Hz - 50.5Hz, first abnormal duration threshold of 1 minute, and second abnormal duration threshold of 30 seconds are only one example. In actual applications, they can be flexibly adjusted according to actual needs to adapt to different grid environments and operating conditions. Therefore, the voltage threshold range, frequency threshold range, first abnormal duration threshold, second abnormal duration threshold, etc. are not limited here.

[0070] In the embodiments of the present application, by combining the dual judgments of voltage and frequency, it is possible to accurately determine whether there is an abnormality in the power measurement data, and by combining the duration of the abnormality, it is possible to accurately determine whether there is an islanding effect, significantly reducing misjudgments caused by instantaneous fluctuations or interference, which helps to further improve the detection accuracy of the islanding effect.

[0071] Considering that in the related art, after the power grid resumes power supply, the process of the photovoltaic power station connecting to the grid requires manual intervention. It can only be reconnected to the grid by relying on manual inspection and manual operation. This operation method is not only complex and inefficient, but also requires a large amount of time and labor costs, increasing the operation and maintenance burden. Moreover, the delay of manual operation may lead to too long grid connection recovery time, affecting the power generation efficiency of the photovoltaic power station and the stability of the power grid. Therefore, in some embodiments, the anti-islanding protection method of the photovoltaic power station further includes: when the power measurement data meets the preset threshold range, determining that the power measurement data is normal; according to the historical power measurement data within the most recent preset duration, determining the duration of the power measurement data being normal; when the duration of being normal is greater than the normal duration threshold, controlling the closing of the grid connection switch in the photovoltaic grid connection system to achieve the automatic grid connection of the photovoltaic power station.

[0072] Exemplarily, when the power measurement data meets the preset threshold range, for example, when the voltage is within the voltage threshold range of 210V - 230V, the frequency is within the frequency threshold range of 49.5Hz - 50.5Hz, or the voltage is within the voltage threshold range and the frequency is within the frequency threshold range, it is determined that the power measurement data is normal; according to the historical power measurement data within the most recent preset duration, such as within 5 minutes, the duration of the power measurement data being normal is determined. For example, within 5 minutes, if the voltage and frequency continuously remain stable within the threshold range, the duration of being normal is 5 minutes; when the duration of being normal is greater than the normal duration threshold, such as 3 minutes, a closing instruction is sent to the grid connection switch in the photovoltaic grid connection system, and this closing instruction is used to control the closing of the grid connection switch to achieve the automatic grid connection of the photovoltaic power station; when the duration of being normal is less than or equal to the normal duration threshold, such as 3 minutes, the closing of the grid connection switch in the photovoltaic grid connection system is not triggered, reducing misclosing caused by instantaneous fluctuations.

[0073] In the embodiments of the present application, by automatically detecting the power measurement data and the duration of being normal, and automatically closing the switch when the duration of being normal exceeds the normal duration threshold, the automatic grid connection function of the photovoltaic power station is realized, effectively shortening the grid connection recovery time, reducing the time delay of manual inspection and operation, and significantly improving the efficiency and reliability of grid connection recovery; in addition, the automatic grid connection function reduces the dependence on manual intervention, reduces the time and labor costs of operation and maintenance, and at the same time reduces misclosing or delayed closing caused by manual operation errors. This not only provides strong support for the efficient operation and intelligent management of the photovoltaic power station, but also further improves the power generation efficiency of the photovoltaic power station and the reliability of the overall system.

[0074] Based on the above embodiments, in some embodiments, when the duration of no anomaly is greater than the normal duration threshold, controlling the closing of the grid-connected switch in the photovoltaic grid-connected system includes: when the duration of no anomaly is greater than the normal duration threshold, obtaining the bus voltage on the grid side in the photovoltaic grid-connected system; comparing the voltage at the grid connection point and the bus voltage; if the voltage at the grid connection point is the same as the bus voltage, then controlling the closing of the grid-connected switch in the photovoltaic grid-connected system.

[0075] Exemplarily, when the duration of no anomaly exceeds the normal duration threshold, for example, 5 minutes, it is determined that the grid has returned to stability and initially meets the grid connection conditions; further, the bus voltage on the grid side is obtained through a voltage transformer. For example, the bus voltage is 220V; the current voltage data at the grid connection point is obtained through a voltage transformer and compared with the bus voltage; for example, the grid connection point voltage is 220V and the bus voltage is 220V, it is determined that the two are the same, then the grid-connected switch in the photovoltaic grid-connected system is controlled to close; if the grid connection point voltage is 215V and the bus voltage is 220V, it is determined that the two are inconsistent, then the grid-connected switch in the photovoltaic grid-connected system is not triggered to close.

[0076] In the embodiments of the present application, by further comparing the voltage at the grid connection point and the bus voltage when the duration of no anomaly exceeds the normal duration threshold, and automatically closing the switch after ensuring that the grid connection conditions are fully met, the dual verification mechanism effectively reduces equipment failures or grid fluctuations caused by inconsistent voltages, significantly improves the reliability and safety of grid connection restoration, and has a positive significance for ensuring the safe operation of photovoltaic power stations and the grid.

[0077] In some embodiments, the anti-islanding protection method for a photovoltaic power station further includes at least one of the following: reporting power measurement data to a power management system; when the duration of an anomaly is greater than the anomaly duration threshold, reporting a fault alarm message to the power management system, where the fault alarm message includes the occurrence time of the islanding effect and the disconnection time of the grid-connected switch; when the duration of no anomaly is greater than the normal duration threshold, reporting a fault clearance message to the power management system, where the fault clearance message includes the clearance time of the islanding effect and the closing time of the grid-connected switch.

[0078] Exemplarily, in the first implementation manner, power measurement data at the grid connection point, including voltage, current, and frequency, etc., is reported to the power management system in real time. For example, voltage, current, and frequency data are reported once every 5 seconds.

[0079] In the second implementation manner, when the duration of an anomaly exceeds the anomaly duration threshold, for example, 1 minute, it is determined that an islanding effect has occurred, the protection action is triggered to disconnect the grid-connected switch, and at the same time, a fault alarm message is reported to the power management system, including: the occurrence time of the islanding effect, for example, is 10:00:00 on October 1, 2023, and the disconnection time of the grid-connected switch, for example, is 10:00:05 on October 1, 2023.

[0080] In the third implementation method, when the duration of no anomaly exceeds the normal duration threshold, such as 5 minutes, the system determines that the power grid has returned to stability and automatically closes the switch to connect to the grid. At the same time, it reports the information of fault elimination to the power management system, including: the elimination time of the islanding effect, such as 10:05:00 on October 1, 2023, and the closing time of the grid connection switch, such as 10:10:00 on October 1, 2023.

[0081] In the fourth implementation method, it reports the power measurement data of the grid connection point to the power management system in real time, including voltage, current, frequency, etc.; and when the duration of anomaly exceeds the anomaly duration threshold, such as 1 minute, it determines that the islanding effect occurs, triggers the protection action to disconnect the grid connection switch, and at the same time reports the fault alarm information to the power management system; and when the duration of no anomaly exceeds the normal duration threshold, such as 5 minutes, the system determines that the power grid has returned to stability, automatically closes the switch to connect to the grid, and at the same time reports the information of fault elimination to the power management system

[0082] It should be noted that the above several implementation methods are only examples. In actual applications, the implementation methods include but are not limited to the above examples. Optionally, one of the implementation methods can be adopted, or several implementation methods can be combined. Specific limitations are not made here.

[0083] In the embodiments of the present application, by transmitting the real-time power measurement data, fault alarm information, and fault elimination information to the upper-layer management system, the relevant operation and maintenance personnel of the power grid monitoring center and the photovoltaic power station can remotely obtain the grid connection status, detection results, and fault information of the photovoltaic power station, which provides convenience for remote monitoring and fault alarm, not only provides data support for remote maintenance and optimization, but also provides a strong guarantee for the safe operation and efficient management of the photovoltaic grid-connected system.

[0084] In some embodiments, the anti-islanding protection method for a photovoltaic power station further includes: storing the protection action data when the grid connection switch in the photovoltaic grid-connected system is disconnected or closed. The protection action data is used for retrospective analysis of the islanding effect and evaluation of the protection effect of the photovoltaic grid-connected system. The protection action data includes the moment when the grid connection switch is triggered to be disconnected or closed, the power measurement data at that moment, and the historical power measurement data within the most recent preset duration before the trigger.

[0085] Exemplarily, when the grid-connected switch is disconnected, record the moment of triggering the disconnection, such as 10:00:05 on October 1, 2023, and store the power measurement data at this moment (such as voltage 190V, frequency 50.2Hz), as well as the historical power measurement data within 5 minutes before the trigger (such as the voltage gradually decreasing from 220V to 190V, and the frequency gradually increasing from 50.0Hz to 50.2Hz); when the grid-connected switch is closed, record the moment of triggering the closing, such as 10:10:00 on October 1, 2023, and store the power measurement data at this moment (such as voltage 220V, frequency 50.0Hz), as well as the historical power measurement data within 5 minutes before the trigger (such as the voltage gradually increasing from 198V to 220V, and the frequency gradually recovering from 49.8Hz to 50.0Hz).

[0086] In the embodiments of the present application, by storing the protection action data when the grid-connected switch is disconnected or closed, it is convenient to analyze the occurrence reasons and development process of the islanding effect, provide reliable data support for subsequent fault troubleshooting and system optimization, and can help the operation and maintenance personnel quickly locate the root cause of the problem; by retrospectively analyzing the occurrence frequency and reasons of the islanding effect and combining with the protection effect evaluation, potential problems can be discovered and solved in time, avoiding the further expansion of faults, and at the same time, it is helpful to optimize the protection strategy, thereby reducing the damage of the islanding effect to the power grid and equipment; in addition, the long-term accumulated protection action data also provides a scientific basis for optimizing the detection algorithm, thereby further improving the accuracy of the islanding effect detection and providing data support for the operation and management of the photovoltaic power station and the power grid, facilitating the formulation of more reasonable operation and maintenance plans and equipment upgrade strategies.

[0087] Figure 2 Another flow schematic diagram of the anti-islanding protection method for a photovoltaic power station provided by an exemplary embodiment of the present application. As Figure 2 shown, the anti-islanding protection method for the photovoltaic power station includes the following steps:

[0088] S201. Control the inverter of the photovoltaic power station to continuously inject a disturbance signal into the photovoltaic grid-connected system.

[0089] Exemplarily, an active detection method is adopted. For example, based on the active islanding detection algorithm, control the inverter of the photovoltaic power station to generate a disturbance signal and superimpose it on the normal output voltage or frequency. Among them, the injection of the disturbance signal is periodic, for example, injected once every 5 seconds to ensure continuous monitoring of the state of the photovoltaic grid-connected system. Among them, the active islanding detection algorithm includes, but is not limited to, the Active Frequency Drift (AFD), Slip-Mode Frequency Shift (SMS), voltage harmonic injection method, impedance measurement method, and power disturbance-based detection method, etc.

[0090] S202. After injecting the disturbance signal, monitor the power measurement data at the grid connection point of the photovoltaic grid-connected system.

[0091] Exemplarily, after injecting the disturbance signal, the power measurement data at the grid connection point is monitored in real time through a mutual inductor installed at the grid connection point, such as a voltage transformer.

[0092] S203. Determine whether the power measurement data exceeds the preset threshold range.

[0093] Exemplarily, assume that the voltage threshold range is 210V - 230V and the frequency threshold range is 49.5Hz - 50.5Hz. Correspondingly, in one implementation, if the voltage is lower than 210V or exceeds 230V, it is determined that the power measurement data is abnormal; in another implementation, if the frequency is lower than 49.5Hz or exceeds 50.5Hz, it is determined that the power measurement data is abnormal; in yet another implementation, if the voltage is lower than 210V or exceeds 230V, and the frequency is lower than 49.5Hz or exceeds 50.5Hz, it is determined that the power measurement data is abnormal.

[0094] If so, execute S204;

[0095] If not, execute S202.

[0096] S204. Determine that the power measurement data is abnormal, and determine the abnormal duration of the power measurement data according to the historical power measurement data within the most recent preset duration.

[0097] Exemplarily, when it is determined that the current power measurement data is abnormal, obtain the historical power measurement data within the most recent preset duration, such as 5 minutes, stored locally. Combine the historical power measurement data to calculate the duration of the abnormal state. For example, if the power measurement data exceeds the preset threshold range for 1 minute within 5 minutes, the abnormal duration is 1 minute; if the power measurement data exceeds the preset threshold range for 30 seconds within 5 minutes, the abnormal duration is 30 seconds.

[0098] S205. Determine whether the abnormal duration is greater than the abnormal duration threshold.

[0099] If so, execute S206;

[0100] If not, execute S202.

[0101] S206. Control the grid connection switch in the photovoltaic grid-connected system to disconnect to perform anti-islanding protection on the photovoltaic power station.

[0102] For example, when the abnormal duration exceeds a preset abnormal duration threshold, such as 1 minute, it is determined that an islanding effect has occurred, and the grid-connected switch in the photovoltaic grid-connected system is immediately controlled to disconnect. By promptly cutting off the output of the photovoltaic power station under the islanding effect, anti-islanding protection of the photovoltaic power station is achieved, ensuring safe isolation and preventing the spread of the islanding effect.

[0103] Furthermore, after injecting the disturbance signal, continue to monitor the power measurement data at the grid connection point in the photovoltaic grid-connected system; when the power measurement data meets the preset threshold range, determine that the power measurement data is normal; determine the abnormal continuous duration of the power measurement data according to the historical power measurement data within the most recent preset duration; when the abnormal continuous duration is greater than the normal duration threshold, obtain the bus voltage on the grid side in the photovoltaic grid-connected system; compare the voltage at the grid connection point with the bus voltage; if the voltage at the grid connection point is the same as the bus voltage, control the grid-connected switch in the photovoltaic grid-connected system to close.

[0104] In summary, the present application has at least the following advantages:

[0105] First, by actively injecting a disturbance signal into the grid-connected system, the dependence on the natural fluctuations of voltage and frequency in the traditional passive detection method is broken through, significantly improving the detection sensitivity; by real-time monitoring the power measurement data at the grid connection point and comparing it with the preset threshold range, abnormal situations can be quickly identified, effectively reducing the occurrence of false positives or false negatives; at the same time, by combining the historical power measurement data to determine the abnormal continuous duration and judging whether it is an islanding effect based on the abnormal continuous duration, the detection accuracy is further improved, reducing false positives caused by instantaneous fluctuations, thus significantly improving the accuracy of islanding detection and ensuring that the islanding effect can be detected in a timely manner; in addition, after determining the existence of the islanding effect, the grid-connected switch is automatically controlled to disconnect, ensuring that the islanding effect can be processed in a timely manner, and on the premise of ensuring the safety of the photovoltaic grid-connected system, reducing the number of trips caused by false positives as much as possible, significantly improving the safety and stability of the photovoltaic power station, and at the same time reducing the risk of damage to the power grid and equipment caused by the islanding effect.

[0106] Second, by combining the dual judgments of voltage and frequency, it is possible to accurately judge whether there is an abnormality in the power measurement data, and by combining the abnormal continuous duration, it is possible to accurately judge whether there is an islanding effect, significantly reducing false positives caused by instantaneous fluctuations or interference, which helps to further improve the detection accuracy of the islanding effect.

[0107] III. By automatically detecting the power measurement data and the duration of no anomaly, and automatically closing the switch when the duration of no anomaly exceeds the normal duration threshold, the automatic grid connection function of the photovoltaic power station is realized, effectively shortening the grid connection recovery time, reducing the time delay of manual inspection and operation, and significantly improving the efficiency and reliability of grid connection recovery. In addition, the automatic grid connection function reduces the dependence on manual intervention, reduces the time and labor costs of operation and maintenance, and at the same time reduces the misclosing or delayed closing caused by manual operation errors. This not only provides strong support for the efficient operation and intelligent management of the photovoltaic power station, but also further improves the power generation efficiency of the photovoltaic power station and the reliability of the overall system.

[0108] IV. When the duration of no anomaly exceeds the normal duration threshold, by further comparing the grid connection point voltage with the bus voltage and automatically closing the switch after ensuring that the grid connection conditions are fully met, the dual verification mechanism effectively reduces the equipment failures or grid fluctuations caused by voltage inconsistency, significantly improving the reliability and safety of grid connection recovery, which has a positive significance for ensuring the safe operation of the photovoltaic power station and the power grid.

[0109] The following is an embodiment of the device of the present application, which can be used to execute the method embodiment of the present application. For the details not disclosed in the embodiment of the device of the present application, please refer to the method embodiment of the present application.

[0110] Figure 3 FIG. is a schematic structural diagram of an anti-islanding protection device for a photovoltaic power station provided by an exemplary embodiment of the present application. The anti-islanding protection device 30 for a photovoltaic power station provided by the embodiment of the present application includes a control and protection module 31, a data acquisition module 32, and a data processing module 33, wherein:

[0111] The control and protection module 31 is used to control the inverter of the photovoltaic power station to continuously inject disturbance signals into the photovoltaic grid connection system;

[0112] The data acquisition module 32 is used to monitor the power measurement data of the grid connection point in the photovoltaic grid connection system after injecting the disturbance signal;

[0113] The data processing module 33 is used to determine that the power measurement data is abnormal when the power measurement data exceeds the preset threshold range; and determine the abnormal duration of the power measurement data according to the historical power measurement data within the most recent preset duration;

[0114] The control and protection module 31 is further used to control the grid connection switch in the photovoltaic grid connection system to disconnect when the abnormal duration is greater than the abnormal duration threshold, so as to perform anti-islanding protection on the photovoltaic power station.

[0115] In a possible implementation, the power measurement data includes voltage and frequency, the threshold range includes a voltage threshold range and a frequency threshold range, and the data processing module 33 can be specifically used to: when the voltage exceeds the voltage threshold range and / or the frequency exceeds the frequency threshold range, determine that there is an abnormality in the power measurement data.

[0116] In a possible implementation, the control and protection module 31 may be specifically used to control the grid-connected switch in the photovoltaic grid-connected system to disconnect when the duration of the first abnormality corresponding to the voltage is greater than the first abnormality duration threshold, and / or when the duration of the second abnormality corresponding to the frequency is greater than the second abnormality duration threshold.

[0117] In a possible implementation, the data processing module 33 is also used to: determine that the power measurement data is normal when the power measurement data meets a preset threshold range; determine the duration of the power measurement data being normal based on historical power measurement data within a recent preset time period; and control the grid-connected switch in the photovoltaic grid-connected system to close when the duration of the normal time period is greater than a normal time threshold, so as to realize automatic grid connection of the photovoltaic power station.

[0118] In a possible implementation, the control and protection module 31 is also used to: obtain the bus voltage on the grid side of the photovoltaic grid-connected system when the duration without abnormality is greater than the normal duration threshold; compare the voltage of the grid-connected point with the bus voltage; if the voltage of the grid-connected point is consistent with the bus voltage, control the grid-connected switch in the photovoltaic grid-connected system to close.

[0119] Figure 4 Another structural schematic diagram of the photovoltaic power station anti-islanding protection device provided by the exemplary embodiment of the present application. The photovoltaic power station anti-islanding protection device 30 provided by the embodiment of the present application also includes: a data storage and fault analysis module 34 and a communication module 35, wherein:

[0120] The data storage and fault analysis module 34 is used to store the protection action data when the grid-connected switch in the photovoltaic grid-connected system is triggered to disconnect or close. The protection action data is used for retrospective analysis of the islanding effect and evaluation of the protection effect of the photovoltaic grid-connected system. The protection action data includes the time when the grid-connected switch is triggered to disconnect or close, the power measurement data at that time, and the historical power measurement data within the most recent preset time before the trigger.

[0121] The communication module 35 is used for at least one of the following: reporting power measurement data to the power management system; reporting fault alarm information to the power management system when the duration of the abnormality is greater than the abnormal duration threshold, the fault alarm information includes the occurrence time of the islanding effect and the disconnection time of the grid-connected switch; reporting fault relief information to the power management system when the duration of no abnormality is greater than the normal duration threshold, the fault relief information includes the relief time of the islanding effect and the closing time of the grid-connected switch.

[0122] Exemplarily, Figure 5 is a schematic structural diagram of an anti-islanding protection device for a photovoltaic power station provided by an exemplary embodiment of the present application. As Figure 5As shown, each module is tightly integrated in the anti-islanding protection device of the photovoltaic power station. Among them, current transformers such as current transformers and voltage transformers are integrated in the data acquisition module, which is used to monitor the power measurement data of the grid connection point in the photovoltaic grid-connected system. The power measurement data will be used as the key input for islanding effect detection. The data processing module internally integrates a high-speed digital signal processor (Digital Signal Processor, DSP for short) or a microcontroller unit (Microcontroller Unit, MCU for short), which is used to calculate the changes in power measurement data such as voltage and frequency, and when the power measurement data exceeds the preset threshold range, it is determined that the power measurement data is abnormal. In addition, based on the historical power measurement data within the recently preset time period, the abnormal duration of the power measurement data is determined. Correspondingly, the control and protection module is used to control the inverter of the photovoltaic power station to continuously inject disturbance signals into the photovoltaic grid-connected system, and when the abnormal duration is greater than the abnormal duration threshold, it is determined that an islanding effect has occurred, or when a grid anomaly is detected, a tripping command is immediately issued to quickly disconnect the connection between the photovoltaic power station and the grid. This function adopts a combination of hardware and software, and realizes precise disconnection operation through the control loop, minimizing the impact of the photovoltaic power station on the grid stability. Further, when the grid resumes normal power supply and reaches the allowable voltage threshold range and frequency threshold range, the automatic closing function will judge whether the grid has returned to stability by detecting the consistency of the bus voltage on the grid side and the grid connection point voltage. If they are consistent, an automatic reclosing command will be issued to restore the grid connection of the photovoltaic power station, effectively shortening the grid connection recovery time, reducing the time delay of manual inspection and operation, and significantly improving the efficiency, reliability and automation of grid connection recovery. In addition, the automatic grid connection function reduces the dependence on manual intervention, reduces the time and labor costs of operation and maintenance, and at the same time reduces misclosing or delayed closing caused by manual operation errors, which not only provides strong support for the efficient operation and intelligent management of the photovoltaic power station, but also further improves the power generation efficiency of the photovoltaic power station and the reliability of the overall system. In addition, the data storage and fault analysis module is used to record the key data of each islanding effect detection and protection action, such as voltage value, frequency value, protection trigger time and detection result, etc. This module helps to analyze the cause of the fault and the operation and maintenance of the equipment, provides reliable data support for the operation management of the photovoltaic power station and the grid, and at the same time, through the long-term accumulation and analysis of data, it can also help to optimize the detection algorithm and protection strategy, and improve the intelligent level of the equipment. Further, the communication module transmits the real-time acquisition data and fault alarm information to the upper management system such as the power management system, enabling relevant operation and maintenance personnel of the grid monitoring center and the photovoltaic power station to remotely obtain the grid connection status, detection results and fault information of the photovoltaic power station, providing convenience for remote monitoring and fault alarm, not only providing data support for remote maintenance and optimization, but also providing strong guarantee for the safe operation and efficient management of the photovoltaic grid-connected system.

[0123] The anti-islanding protection device for a photovoltaic power station provided by an embodiment of the present application is not only applicable to the anti-islanding protection of photovoltaic power generation, but also compatible with the low-voltage grid connection protection of other types of distributed power sources, and has broad application prospects.

[0124] The anti-islanding protection device for a photovoltaic power station provided by an embodiment of the present application can implement the technical solutions shown in the above embodiments of the anti-islanding protection method for a photovoltaic power station. The implementation principle and beneficial effects are similar, and will not be elaborated here.

[0125] It should be noted that it should be understood that the division of each module of the above device is only a division of logical functions. In actual implementation, it can be fully or partially integrated into a physical entity, or physically separated. And these modules can all be implemented in the form of software called by a processing element; they can also all be implemented in the form of hardware; or some modules can be implemented in the form of software called by a processing element, and some modules can be implemented in the form of hardware. For example, the control and protection module can be a separately established processing element, or can be integrated in a certain chip of the above device. In addition, it can also be stored in the memory of the above device in the form of program code, and called and executed by a certain processing element of the above device to perform the functions of the above control and protection module. The implementation of other modules is similar. In addition, all or part of these modules can be integrated together or can be independently implemented. Here, the processing element can be an integrated circuit with signal processing capabilities. In the implementation process, each step of the above method or each of the above modules can be completed by the integrated logic circuit in the processor element or the instruction in the form of software.

[0126] For example, the above modules can be one or more integrated circuits configured to implement the above method, such as: one or more application specific integrated circuits (ASICs), or, one or more digital signal processors (DSPs), or, one or more field programmable gate arrays (FPGAs), etc. Again, when a certain module above is implemented in the form of a processing element scheduling program code, the processing element can be a general-purpose processor, such as a central processing unit (CPU) or other processors that can call program code. Again, these modules can be integrated together to be implemented in the form of a system-on-a-chip (SOC).

[0127] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer instructions are loaded and executed on a computer, the processes or functions according to the embodiments of the present application are generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from a website, computer, server, or data center to another website, computer, server, or data center in a wired manner (such as coaxial cable, optical fiber, Digital Subscriber Line (DSL)) or a wireless manner (such as infrared, wireless, microwave, etc.). The computer-readable storage medium can be any available medium that the computer can access or a data storage device such as a server or data center that includes one or more integrated available media. The available medium can be a magnetic medium (such as a floppy disk, hard disk, magnetic tape), an optical medium (such as a Digital Video Disc (DVD)), or a semiconductor medium (such as a solid state disk (SSD)).

[0128] Figure 6 The structural schematic diagram of the electronic device provided for the exemplary embodiment of the present application. As Figure 6 shown, the electronic device 60 in this embodiment includes:

[0129] At least one processor 61; and a memory 62 communicatively connected to the at least one processor;

[0130] Wherein, the memory 62 stores instructions executable by the at least one processor 61, and the instructions are executed by the at least one processor 61 to cause the electronic device to execute the method described in any of the above embodiments.

[0131] Optionally, the memory 62 can be either independent or integrated with the processor 61.

[0132] The memory 62 may include a high-speed random access memory (Random Access Memory, RAM) and may also include non-volatile memory, such as at least one disk memory.

[0133] The processor 61 may be a Central Processing Unit (CPU), or an Application Specific Integrated Circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of the present application. Specifically, when implementing the anti-islanding protection method for a photovoltaic power station described in the foregoing method embodiments, the electronic device may be, for example, an electronic device with processing capabilities such as a server.

[0134] Optionally, the electronic device may further include a communication interface 63. In a specific implementation, if the communication interface 63, the memory 62, and the processor 61 are implemented independently, the communication interface 63, the memory 62, and the processor 61 may be interconnected through a bus and communicate with each other. The bus may be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. The bus may be divided into an address bus, a data bus, a control bus, etc., but it does not mean that there is only one bus or one type of bus.

[0135] Optionally, in a specific implementation, if the communication interface 63, the memory 62, and the processor 61 are implemented integrated on a chip, the communication interface 63, the memory 62, and the processor 61 may communicate through an internal interface.

[0136] The implementation principle and technical effects of the electronic device provided in this embodiment may be referred to the foregoing embodiments, and will not be elaborated here.

[0137] The embodiments of the present application further provide a computer-readable storage medium, in which computer-executable instructions are stored. When the computer-executable instructions are executed, they are used to implement the method steps in the method embodiments as described above. The specific implementation manners and technical effects are similar and will not be elaborated here.

[0138] The above-mentioned computer-readable storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as Static Random Access Memory (SRAM), Electrically Erasable Programmable Read Only Memory (EEPROM), Erasable Programmable Read Only Memory (EPROM), Programmable Read Only Memory (PROM), Read Only Memory (ROM), magnetic memory, flash memory, magnetic disk or optical disc. The readable storage medium can be any available medium accessible by a general-purpose or special-purpose computer.

[0139] An exemplary readable storage medium is coupled to the processor, enabling the processor to read information from and write information to the readable storage medium. Of course, the readable storage medium can also be a component of the processor. The processor and the readable storage medium can be located in an application-specific integrated circuit. Of course, the processor and the readable storage medium can also exist as discrete components in the anti-islanding protection device of a photovoltaic power station.

[0140] The embodiments of the present application further provide a computer program product, including a computer program which, when executed, implements the method steps in the above-mentioned method embodiments. The specific implementation manners and technical effects are similar and will not be elaborated here.

[0141] In the above embodiments, the descriptions of the various embodiments have their own emphases. For parts not detailed in a certain embodiment, reference can be made to the relevant descriptions of other embodiments. The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as within the scope described in this specification.

[0142] Those of ordinary skill in the art can understand that all or part of the steps of implementing the above method embodiments can be completed by hardware related to program instructions. The foregoing program can be stored in a computer-readable storage medium. When the program is executed, it performs the steps including the above method embodiments; and the foregoing storage medium includes various media such as ROM, RAM, magnetic disk or optical disc that can store program codes.

[0143] Finally, it should be noted that those skilled in the art will readily conceive of other embodiments of the present invention after considering the specification and practicing the invention disclosed herein. The present invention is intended to cover any variations, uses, or adaptations of the present invention, which follow the general principles of the present invention and include known common knowledge or conventional technical means in the technical field not disclosed in the present invention. It is not limited to the exact structures described above and shown in the drawings, and various modifications and changes can be made without departing from its scope. The scope of the present invention is only limited by the appended claims.

Claims

1. A method for anti-islanding protection of a photovoltaic power station, characterized in that, include: Controlling the inverter of the photovoltaic power station to continuously inject a disturbance signal into the photovoltaic grid-connected system; After injecting the disturbance signal, monitoring the power measurement data of the grid-connected point in the photovoltaic grid-connected system; When the power measurement data exceeds a preset threshold range, determining that the power measurement data is abnormal; Determine the duration of abnormality in the power measurement data based on historical power measurement data within a recent preset time period; When the duration of the abnormality is greater than the abnormality duration threshold, the grid-connected switch in the photovoltaic grid-connected system is controlled to be disconnected to perform anti-islanding protection on the photovoltaic power station.

2. The method for anti-islanding protection of a photovoltaic power station according to claim 1, wherein The power measurement data includes voltage and frequency, the threshold range includes a voltage threshold range and a frequency threshold range, and when the power measurement data exceeds a preset threshold range, determining that the power measurement data is abnormal includes: If the voltage exceeds the voltage threshold range, and / or the frequency exceeds the frequency threshold range, it is determined that an abnormality exists in the power measurement data.

3. The anti-islanding protection method for a photovoltaic power station according to claim 2, characterized in that, When the duration of the abnormality is greater than the abnormality duration threshold, controlling the grid-connected switch in the photovoltaic grid-connected system to disconnect includes: If the duration of the first abnormality corresponding to the voltage is greater than the first abnormality duration threshold, and / or the duration of the second abnormality corresponding to the frequency is greater than the second abnormality duration threshold, the grid-connected switch in the photovoltaic grid-connected system is controlled to be disconnected.

4. The anti-islanding protection method for a photovoltaic power station according to any one of claims 1 to 3, characterized in that, Also includes: When the power measurement data meets a preset threshold range, determining that the power measurement data has no abnormality; Determine the duration of no abnormality in the power measurement data based on the historical power measurement data within a recent preset time period; When the duration without abnormality is longer than the normal duration threshold, the grid-connected switch in the photovoltaic grid-connected system is controlled to close, so as to realize automatic grid connection of the photovoltaic power station.

5. The anti-islanding protection method for a photovoltaic power station according to claim 4, characterized in that, When the duration of the absence of abnormality is greater than the normal duration threshold, controlling the grid-connected switch in the photovoltaic grid-connected system to close includes: When the duration without abnormality is longer than a normal duration threshold, obtaining a bus voltage on the grid side of the photovoltaic grid-connected system; Comparing the voltage of the grid connection point with the bus voltage; If the voltage of the grid-connected point is consistent with the bus voltage, the grid-connected switch in the photovoltaic grid-connected system is controlled to close.

6. The anti-islanding protection method for a photovoltaic power station according to claim 5, wherein, Also includes at least one of the following: Reporting the power measurement data to a power management system; When the duration of the abnormality is greater than the abnormality duration threshold, reporting fault alarm information to the power management system, the fault alarm information including the occurrence time of the islanding effect and the disconnection time of the grid-connected switch; When the duration without abnormality is longer than the normal duration threshold, fault relief information is reported to the power management system, where the fault relief information includes the relief time of the islanding effect and the closing time of the grid-connected switch.

7. The anti-islanding protection method for a photovoltaic power station according to any one of claims 1 to 3, characterized in that, Also includes: The protection action data when the grid-connected switch in the photovoltaic grid-connected system is triggered to be disconnected or closed is stored. The protection action data is used for retrospective analysis of the islanding effect and protection effect evaluation of the photovoltaic grid-connected system. The protection action data includes the moment when the grid-connected switch is triggered to be disconnected or closed, the power measurement data at the moment, and the historical power measurement data within the most recent preset time period before the triggering.

8. A photovoltaic power station anti-islanding protection device, characterized in that, Comprising: A control and protection module, configured to control an inverter of the photovoltaic power station to continuously inject a disturbance signal into the photovoltaic grid-connected system; A data acquisition module, configured to monitor power measurement data at a grid connection point in the photovoltaic grid-connected system after the disturbance signal is injected; A data processing module, configured to determine that the power measurement data is abnormal when the power measurement data exceeds a preset threshold range; and determine the abnormal duration of the power measurement data according to historical power measurement data within a recently preset duration; The control and protection module is further configured to control a grid connection switch in the photovoltaic grid-connected system to disconnect when the abnormal duration is greater than an abnormal duration threshold, so as to perform anti-islanding protection on the photovoltaic power station.

9. An electronic device, characterized in that, Comprising: A processor and a memory communicatively connected to the processor; The memory is configured to store computer execution instructions; The processor is configured to execute the computer execution instructions to implement the method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, Computer execution instructions are stored in the computer-readable storage medium, and when the computer execution instructions are executed, they are used to implement the method according to any one of claims 1 to 7.

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