Power grid system detection method and device, electronic equipment, medium and product

Abstract

The invention provides a power grid system detection method and device, electronic equipment, a medium and a product. The power grid system comprises an inverter and a sampling device which are connected to a power grid; wherein the sampling device is used for collecting electrical parameters of a power grid, and the sampling device does not pass through a load before being connected to the power grid; the method comprises the following steps: acquiring first reactive power emitted by an inverter in a grid-connected state; obtaining a first increment of the reactive power emitted by the power grid before and after the inverter emits the first reactive power according to the electrical parameters collected by the sampling device before and after the inverter emits the first reactive power; and if the difference between the first reactive power and the first increment does not exceed the preset range, determining that the connection of the sampling device is correct. According to the scheme, the accuracy of power grid system detection can be improved.

Description

Technical Field

[0001] The present application relates to the field of photovoltaic power generation and energy storage technology, and in particular to a detection method, device, electronic equipment, medium and product for a power grid system. Background Art

[0002] The global demand for renewable energy is growing, and photovoltaic power generation, as a clean and renewable energy source, is becoming more and more widely used. Photovoltaic energy storage systems usually include photovoltaic arrays, inverters, batteries and other equipment. Among them, the inverter is one of the key equipment, which is responsible for converting the DC power generated by the photovoltaic array into AC power and connecting it to the power grid or supplying it to households. However, there are many different power distribution schemes for grid-connected energy storage inverters. In some countries and regions, due to the tight power grid, the power supply bureau will have certain restrictions on the inverter to draw power from the grid or generate power. Generally, it is necessary to connect a sampling device to the inverter grid-connected port to sample the grid for power control; therefore, it is necessary to detect whether the sampling device is working properly to ensure the accuracy of power control.

[0003] At present, some detection schemes for power grid systems all determine whether the sampling devices in the power grid are working normally by calculating the actual power of different ports in the power grid. However, due to the volatility in the power grid system, the actual power calculation is inaccurate. Furthermore, due to the inaccurate detection results of the power grid system, it is impossible to accurately determine whether the working status of the sampling devices is normal. Summary of the invention

[0004] The power grid system detection method, device, electronic equipment, medium and product of the present application are used to improve the accuracy of power grid system detection.

[0005] In a first aspect, the present application provides a detection method for a power grid system, wherein the power grid system includes an inverter connected to the power grid and a sampling device; wherein the sampling device is used to collect electrical parameters of the power grid, and the sampling device does not pass through a load before being connected to the power grid; the method includes: obtaining a first reactive power emitted by the inverter in a grid-connected state; obtaining a first increment of reactive power emitted by the power grid before and after the inverter emits the first reactive power based on the electrical parameters collected by the sampling device before and after the inverter emits the first reactive power; if the difference between the first reactive power and the first increment does not exceed a preset range, determining that the connection of the sampling device is correct.

[0006] In a possible implementation, the method further includes: comparing the magnitude and direction of the first reactive power and the first increment; if the magnitude difference between the first reactive power and the first increment does not exceed a preset range, and the direction of the reactive power is consistent with that of the first increment, then determining that the difference between the first reactive power and the first increment does not exceed a preset range.

[0007] In a possible implementation, the method also includes: if the difference between the first reactive power and the first increment exceeds a preset range, controlling the inverter to emit a second reactive power; the second reactive power is the same in magnitude but opposite in direction to the first reactive power; based on the electrical parameters collected by the sampling device before and after the inverter emits the second reactive power, obtaining a second increment of the reactive power emitted by the power grid before and after the inverter emits the second reactive power; if the difference between the second reactive power and the second increment does not exceed the preset range, determining that the connection of the sampling device is correct; otherwise, determining that the connection of the sampling device is incorrect.

[0008] In a possible implementation, the method further includes: if a connection error of the sampling device is detected, controlling the inverter to exit the grid-connected state and issuing an alarm signal.

[0009] In a possible implementation, obtaining a first reactive power generated by the inverter in a grid-connected state includes: obtaining reactive power outputted by the inverter in a grid-connected state according to a preset power limit condition as the first reactive power.

[0010] In a possible implementation manner, obtaining a first reactive power generated by an inverter in a grid-connected state includes: controlling the inverter to generate reactive power of a predetermined magnitude and direction, and using the reactive power as the first reactive power.

[0011] In one possible implementation, obtaining a first increment of reactive power emitted by a power grid before and after an inverter emits a first reactive power includes: calculating a current reactive power based on current voltage effective values ​​and current effective values ​​of the power grid before and after the inverter emits the first reactive power, respectively, to obtain the reactive power of the power grid before and after the inverter emits the first reactive power; and obtaining the first increment by difference calculation based on the reactive power of the power grid before and after the inverter emits the first reactive power.

[0012] In one possible implementation, the current reactive power is calculated based on the current effective value of the voltage and the effective value of the current of the power grid, including: constructing the current power grid voltage function and the current function of the power grid; calculating the current effective value of the voltage and the effective value of the current of the power grid based on the power grid voltage function and the power grid current function; multiplying the current effective value of the voltage and the effective value of the current of the power grid to obtain the current reactive power.

[0013] In one possible implementation, constructing the current grid voltage function and grid current function of the grid includes: obtaining the grid voltage, grid current, voltage zero crossing point, frequency, and current zero crossing point of the grid; constructing the grid voltage function according to the grid voltage and frequency; calculating the phase angle difference between the voltage and the current according to the voltage zero crossing point and the current zero crossing point; and constructing the grid current function according to the phase angle difference between the voltage and the current and the grid current.

[0014] In a possible implementation, the phase difference between voltage and current is calculated based on the voltage zero crossing point and the current zero crossing point, including: respectively obtaining the time of the voltage zero crossing point and the current zero crossing point time; and calculating the phase difference between voltage and current based on the time difference between the voltage zero crossing point time and the current zero crossing point time.

[0015] In a second aspect, the present application provides a detection device for a power grid system, wherein the power grid system includes an inverter and a sampling device connected to the power grid; wherein the sampling device is used to collect electrical parameters of the power grid, and the sampling device does not pass through a load before being connected to the power grid; the device includes: an acquisition module, used to obtain a first reactive power emitted by the inverter in a grid-connected state; the acquisition module is also used to obtain a first increment of reactive power emitted by the power grid before and after the inverter emits the first reactive power based on the electrical parameters collected by the sampling device before and after the inverter emits the first reactive power; a comparison module, used to determine that the connection of the sampling device is correct if the difference between the first reactive power and the first increment does not exceed a preset range.

[0016] In a third aspect, the present application provides an electronic device, including: a memory, a processor;

[0017] The memory stores computer-executable instructions;

[0018] The processor executes the computer-executable instructions stored in the memory, so that the processor executes the above first aspect and / or various possible implementations of the first aspect.

[0019] 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 by a processor, they are used to implement the above first aspect and / or various possible implementations of the first aspect.

[0020] In a fifth aspect, an embodiment of the present application provides a computer program product, including a computer program, which, when executed by a processor, implements the above first aspect and / or various possible implementation methods of the first aspect.

[0021] In the detection method, device, electronic device, medium and product of the power grid system provided by the present application, the power grid system includes an inverter connected to the power grid and a sampling device for collecting electrical parameters of the power grid, and the sampling device does not pass through a load before connecting to the power grid; by obtaining a preset first reactive power emitted by the inverter in a grid-connected state, and according to the electrical parameters collected by the sampling device before and after the inverter emits the first reactive power, a first increment is obtained, and the first increment represents the difference in reactive power in the power grid after the reactive power is emitted and before the reactive power is emitted; the first reactive power is compared with the first increment, and if the difference between the preset first reactive power emitted and the first increment does not exceed the preset range, it is determined that the connection of the sampling device is correct. The scheme of the present application improves the accuracy of the detection results of the power grid system by comparing the reactive power emitted by the inverter with the increment generated in the power grid due to the emitted reactive power. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0023] Figure 1 A schematic diagram of a detection method for a power grid system is shown as an example;

[0024] Figure 2 This is a schematic diagram of a power grid detection system according to an example of the present application;

[0025] Figure 3 A schematic diagram of a detection method for a power grid system is shown as an example;

[0026] Figure 4 A schematic diagram of a detection method for a power grid system is shown as an example;

[0027] Figure 5 A schematic diagram of a flow chart of a detection method for a power grid system of the present application;

[0028] Figure 6 A schematic structural diagram of a detection device for a power grid system is exemplarily shown;

[0029] Figure 7 A structural schematic diagram of an electronic device is exemplarily shown in FIG.

[0030] The above drawings have shown clear embodiments of the present application, which will be described in more detail later. These drawings and text descriptions are not intended to limit the scope 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 DESCRIPTION

[0031] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application. Instead, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0032] It should be noted that the brief description of the terms in this application is only for the convenience of understanding the implementation methods described below, and is not intended to limit the implementation methods of this application. Unless otherwise specified, these terms should be understood according to their common and usual meanings. The terms "first", "second", etc. in the specification and claims and the above-mentioned drawings in this application are used to distinguish similar or similar objects or entities, and do not necessarily mean to limit a specific order or sequence, unless otherwise indicated. It should be understood that the terms used in this way can be interchangeable where appropriate, for example, they can be implemented in an order other than those given in the diagram or description of the embodiment of this application. The terms "including" and "having" in the specification and claims and the above-mentioned drawings in this application and any of their variations are intended to cover but not exclusively include, for example, a product or device containing a series of components is not necessarily limited to those components clearly listed, but may include other components that are not clearly listed or inherent to these products or devices. The term "module" used in this application refers to any known or later developed hardware, software, firmware, artificial intelligence, fuzzy logic or a combination of hardware or / and software code that can perform functions related to the element.

[0033] The global demand for renewable energy is growing, and photovoltaic power generation, as a clean and renewable energy source, is increasingly being used. Photovoltaic energy storage systems usually include photovoltaic arrays, inverters, batteries and other equipment, among which the inverter is one of the key equipment, which is responsible for converting the DC power generated by the photovoltaic array into AC power and connecting it to the grid or supplying it to households. However, there are many different distribution schemes for grid-connected energy storage inverters. In some countries and regions, due to the tight power grid, the power supply bureau will have certain restrictions on the inverter's power supply or power generation from the grid. Generally, it is necessary to connect a sampling device to the inverter's grid-connected port to sample the grid for power control; when the sampling device is connected to the household main grid port, it may be far away from the inverter, and because the sampling device itself has access direction problems, once disconnected or reversed, it will affect the inverter's control of grid-connected power, which may violate the signed power agreement and cause unnecessary economic losses to customers; therefore, it is necessary to detect whether the sampling device is working properly to ensure the accuracy of power control.

[0034] At present, some detection schemes for power grid systems all determine whether the sampling devices in the power grid are working normally by calculating the actual power of different ports in the power grid. However, due to the volatility in the power grid system, the actual power calculation is inaccurate. Furthermore, due to the inaccurate detection results of the power grid system, it is impossible to accurately determine whether the working status of the sampling devices is normal.

[0035] The technical content provided by the present application is intended to solve the above technical problems of the prior art. In the detection method, device, electronic device, medium and product of the power grid system provided by the present application, the power grid system includes an inverter connected to the power grid and a sampling device for collecting electrical parameters of the power grid, and the sampling device does not pass through the load before connecting to the power grid; by obtaining the preset first reactive power emitted by the inverter in the grid-connected state, and according to the electrical parameters before and after the inverter emits the first reactive power collected by the sampling device, a first increment is obtained, and the first increment represents the difference in reactive power in the power grid after the reactive power is emitted and before the reactive power is emitted; the first reactive power is compared with the first increment, and if the difference between the preset first reactive power emitted and the first increment does not exceed the preset range, it is determined that the connection of the sampling device is correct. The scheme of the present application improves the accuracy of the detection results of the power grid system by comparing the reactive power emitted by the inverter with the increment generated in the power grid due to the emitted reactive power.

[0036] The technical solution of the present application and how the technical solution of the present application solves the above-mentioned technical problems are described in detail below with specific embodiments. The following 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.

[0037] Embodiment 1

[0038] Figure 1 A schematic diagram of a detection method for a power grid system is shown as an example. Figure 1 As shown, the power grid system includes an inverter connected to the power grid and a sampling device; wherein the sampling device is used to collect electrical parameters of the power grid, and the sampling device does not pass through a load before being connected to the power grid; the method includes:

[0039] Step 101, obtaining a first reactive power generated by the inverter in a grid-connected state;

[0040] Step 102: obtaining a first increment of reactive power emitted by the power grid before and after the inverter emits the first reactive power based on electrical parameters collected by the sampling device before and after the inverter emits the first reactive power;

[0041] Step 103: If the difference between the first reactive power and the first increment does not exceed a preset range, it is determined that the connection of the sampling device is correct.

[0042] Specifically, Figure 2 This is a schematic diagram of an example power grid detection system of the present application, such as Figure 2 As shown, the power grid detection system includes: an inverter connected to the power grid and a sampling device, the inverter sends a preset reactive power to the power grid, the sampling device collects electrical parameters in the power grid and transmits the electrical parameters to the inverter, the inverter calculates the increment of reactive power in the power grid due to the reactive power sent by the inverter according to the electrical parameters of the power grid, and compares it with the reactive power sent by the inverter, so as to determine whether the connection of the sampling device is correct. This example does not limit the specific type of the sampling device, for example, the sampling device can be a current transformer, an electric meter, etc.; in actual applications, the current transformer mainly collects the current in the power grid; the current transformer can convert the large current on the primary side into a small current on the secondary side for related measurements; the electric meter collects the voltage, current, frequency and other related information in the circuit. It should be noted that when using the electric meter to sample the power grid, the time of the preset reactive power sent by the inverter must be equal to 10 times the reading cycle of the electric meter, otherwise there will be false alarms and other situations, which will affect the subsequent detection results. In actual applications, inverters are used to convert DC power sources such as batteries and solar panels into AC power for use by AC loads, such as household appliances and industrial equipment. At the same time, inverters are an indispensable component of renewable energy systems such as solar photovoltaic power generation and wind power generation. Through inverters, the DC power generated by these renewable energy sources can be converted into AC power, which can then be injected into the public power grid or used directly. For renewable energy sources such as solar energy and wind energy, inverters help maintain the stability and power balance of the entire power grid system and ensure the reliable operation of the power grid by regulating its output power and fluctuations. In this example, when performing a test on the power grid system, the inverter is used to detect whether the sampling device in the power grid is connected correctly to ensure that the sampling device can accurately control the power of the power grid and the normal operation of the power grid system. The solution of the present application is applicable to situations where the sampling device is directly connected to the grid port without passing through any load.

[0043] Specifically, when the inverter is in the grid-connected state, the first reactive power emitted by the inverter is obtained; in practical applications, when the AC power output by the inverter meets the requirements of the public power grid, it will automatically switch to the grid-connected state and connect the electric energy to the public power grid. Reactive power is generated in the AC circuit due to the phase difference between voltage and current. It will not be consumed, but will flow back and forth in the power grid. When the inverter emits the preset first reactive power, it will flow into the power grid. At this time, the first increment is calculated according to the electrical parameters collected by the sampling device; specifically, the sampling device will collect the electrical parameters before the inverter emits the first reactive power, and the electrical parameters after being affected by the emitted first reactive power, and calculate the difference in reactive power in the power grid according to the difference between the electrical parameters before and after the changes, and obtain the corresponding first increment; then, compare the first reactive power with the first increment; if the difference between the two is within the preset difference range, then it is considered that the connection of the power grid sampling device is correct and the sampling device is working normally. In this example, by comparing the preset reactive power emitted by the inverter with the increment in the power grid caused by the reactive power emitted by the inverter, it is determined whether the sampling device is connected correctly and works normally based on the comparison result, thereby improving the accuracy of power grid system detection.

[0044] Furthermore, when comparing the reactive power generated by the inverter with the first increment, it is necessary to compare the magnitude and direction of the reactive power at the same time; accordingly, as an example, the method further includes:

[0045] comparing the magnitude and direction of the first reactive power and the first increment;

[0046] If the difference between the first reactive power and the first increment does not exceed the preset range, and the reactive power is in the same direction as the first increment, it is determined that the difference between the first reactive power and the first increment does not exceed the preset range.

[0047] Specifically, before the inverter sends out the preset reactive power, the sampling device will collect the electrical parameters in the current power grid, such as voltage, current, frequency and other related parameters; after the inverter sends out the preset first reactive power, the preset reactive power will be transmitted to the power grid, and the sampling device will collect the voltage, current, frequency and other electrical parameters in the power grid at this time; the inverter calculates the increment of reactive power in the power grid according to the electrical parameters before and after sending out the preset first reactive power; if the difference between the first reactive power and the first increment is within the preset error range, and the direction of the first reactive power is consistent with that of the first increment, it is determined that the sampling device is correctly connected and is in a normal working state. In practical applications, since there will be certain fluctuations in the power grid during the working process, it is sufficient to determine that the error between the first reactive power and the first increment is within the preset error range. In this example, by comparing the size and direction of the preset reactive power sent by the inverter, the accuracy of the detection result of the power grid system is further improved. At the same time, by comparing the direction, the reverse connection of the sampling device can be accurately detected.

[0048] Furthermore, when the difference between the preset reactive power emitted by the inverter and the first increment exceeds the preset range, further detection is required; accordingly, as an example, Figure 3 A schematic flow chart of a detection method for a power grid system is exemplarily shown; based on any example, the method further includes:

[0049] Step 201: If the difference between the first reactive power and the first increment exceeds a preset range, the inverter is controlled to generate a second reactive power; the second reactive power is the same in magnitude and opposite in direction to the first reactive power;

[0050] Step 202: obtaining a second increment of reactive power emitted by the power grid before and after the inverter emits the second reactive power based on electrical parameters collected by the sampling device before and after the inverter emits the second reactive power;

[0051] Step 203: If the difference between the second reactive power and the second increment does not exceed a preset range, it is determined that the connection of the sampling device is correct; otherwise, it is determined that the connection of the sampling device is incorrect.

[0052] Specifically, when the difference between the first reactive power and the first increment exceeds a preset range, considering that the user's load may have reactive power fluctuations, the inverter is controlled to emit a second reactive power of the same magnitude and opposite direction as the first reactive power; in practical applications, when the load in the power grid system changes, such as the start and stop of the motor, the input and removal of the transformer, etc., reactive power fluctuations will occur. The structure and parameters of the power grid will also affect the distribution and stability of reactive power; for example, the reactive loss of components such as transmission lines and transformers in the power grid, and the switching of reactive compensation equipment such as parallel reactors and capacitors will cause reactive power fluctuations. Similarly, according to the electrical parameters collected by the sampling device before and after the inverter emits the second reactive power, the second increment of the reactive power emitted by the inverter before and after the second reactive power is emitted is obtained; specifically, before the inverter is controlled to emit the second reactive power, the sampling device collects the electrical parameters in the power grid; after the inverter emits the second reactive power, the sampling device collects the electrical parameters in the power grid at this time, and the inverter calculates the second increment of reactive power in the power grid according to the electrical parameters that change before and after the second reactive power is emitted. Afterwards, the difference between the second reactive power and the second increment is compared. If the difference between the second reactive power and the second increment is within the preset range, the sampling device is determined to be correctly connected; otherwise, the sampling device is determined to be incorrectly connected. In this example, taking into account possible load fluctuations in the power grid, when the difference between the preset reactive power emitted for the first time and the reactive power added in the power grid exceeds the preset range, the inverter is controlled to emit a reactive power of the same magnitude and opposite direction as the first time, and then the difference between the reactive power at this time and the increment of the reactive power in the power grid is compared to determine whether the sampling device is correctly connected, thereby further improving the accuracy of power grid system detection.

[0053] Further, when it is detected that the difference between the second reactive power emitted by the inverter and the second increment is still beyond the preset range, it is determined that the sampling device is connected incorrectly; accordingly, as an example, the method further includes:

[0054] If a connection error of the sampling device is detected, the inverter is controlled to exit the grid-connected state and an alarm signal is issued.

[0055] Specifically, when the inverter emits reactive power of the same magnitude and opposite direction as the first time, the difference between the increment of reactive power in the power grid and the reactive power emitted by the inverter still exceeds the preset range; at this time, it is determined that the sampling device is connected incorrectly and cannot work normally; the inverter exits the grid-connected state and issues a corresponding alarm signal, waiting for maintenance. Specifically, when it is determined that the sampling device is damaged, the inverter will automatically exit the grid-connected mode to avoid causing greater impact on the power grid; after the inverter exits the grid-connected mode, it will immediately issue an alarm signal to notify the operation and maintenance personnel to inspect and repair. At the same time, the inverter will enter the standby state, waiting for the maintenance to be completed and recalibrated before resuming grid-connected operation. In this example, when it is determined that the sampling device is connected incorrectly, the inverter exits the grid-connected state and issues an alarm to wait for maintenance, which ensures the normal operation of the power grid system and reduces the impact of the damage to the sampling device on the power grid system.

[0056] Furthermore, the present application needs to obtain the reactive power generated by the inverter, so as to detect the power grid system according to the comparison between the reactive power generated by the inverter and the increment of the reactive power in the power grid. Accordingly, as an example, obtaining the first reactive power generated by the inverter in the grid-connected state includes:

[0057] The reactive power outputted by the inverter in a grid-connected state according to a preset power limit condition is obtained as the first reactive power.

[0058] Specifically, the reactive power emitted by the inverter will be subject to restrictions in different regions. When the region has strict requirements on the grid-connected power feeding of the inverter, the detection interval can be accelerated to speed up the interval for emitting the preset reactive power to avoid failure of the sampling device; when the region has loose requirements on the grid-connected power feeding of the inverter, the detection interval can be appropriately reduced to reduce the interval for emitting the preset reactive power to avoid excessive reactive power emission causing grid voltage fluctuations. Therefore, the reactive power emitted by the inverter under the corresponding preset power limit conditions can be obtained as the first reactive power of this application. In this example, the reactive power emitted by the inverter at regular intervals under the preset power limit conditions is obtained, which improves the detection efficiency of the power grid system.

[0059] Furthermore, obtaining the first reactive power generated by the inverter in the grid-connected state includes:

[0060] The inverter is controlled to emit reactive power of a predetermined magnitude and direction, and the reactive power is used as the first reactive power.

[0061] Specifically, the inverter can also be controlled to emit reactive power of preset magnitude and direction, and the reactive power of preset magnitude and direction can be used as the first reactive power of the present application. In this example, by controlling the inverter to emit reactive power of preset magnitude and direction as the first reactive power, the efficiency of obtaining reactive power is improved, and while ensuring the accuracy of the detection results of the power grid system, the detection efficiency of the power grid system is further improved.

[0062] Specifically, the inverter needs to compare the difference between the increment of reactive power in the power grid and the first reactive power before and after the first reactive power is emitted; accordingly, as an example, Figure 4 A schematic flow chart of a detection method for a power grid system is exemplarily shown; based on any example, obtaining a first increment of reactive power emitted by the power grid before and after the inverter emits a first reactive power includes:

[0063] Step 301: before and after the inverter emits the first reactive power, respectively calculate the current reactive power according to the current effective value of the voltage and the effective value of the current of the power grid to obtain the reactive power of the power grid before and after the inverter emits the first reactive power;

[0064] Step 302: Obtain a first increment by difference calculation based on the reactive power of the power grid before and after the inverter generates the first reactive power.

[0065] Specifically, before the inverter emits the first reactive power, the effective value of the voltage and the effective value of the current of the power grid are obtained; the reactive power in the power grid at this time is calculated according to the effective value of the voltage and the effective value of the current at this time, that is, the reactive power in the power grid before the inverter emits the first reactive power. Similarly, after the inverter emits the first reactive power, the effective value of the voltage and the effective value of the current of the power grid are obtained; the reactive power in the power grid at this time is calculated according to the effective value of the voltage and the effective value of the current at this time, that is, the reactive power in the power grid after the inverter emits the first reactive power. The reactive power in the power grid after the first reactive power is emitted is subtracted from the reactive power in the power grid before the first reactive power is emitted to obtain the first increment; the first increment represents the increased reactive power generated in the power grid due to the inverter emitting the preset reactive power. In this example, the increment of the reactive power in the power grid is calculated according to the effective value of the voltage and the effective value of the current of the power grid before and after the inverter in the power grid emits the preset reactive power, thereby improving the accuracy of reactive power detection in the power grid.

[0066] Furthermore, the current reactive power is calculated based on the current voltage and current effective values ​​of the power grid, including:

[0067] Construct the current grid voltage function and grid current function of the grid;

[0068] According to the grid voltage function and the grid current function, the current voltage effective value and current effective value of the grid are calculated;

[0069] Multiply the current effective value of the voltage and the effective value of the current of the power grid to obtain the current reactive power.

[0070] Specifically, when the current reactive power needs to be calculated based on the current voltage RMS value and current RMS value of the power grid, first, the current power grid voltage function and power grid current function need to be constructed; specifically, the corresponding power grid voltage function and power grid current function need to be constructed based on the electrical parameters in the power grid collected by the sampling device. Then, the voltage RMS value is obtained based on the constructed power grid voltage function, and the current RMS value is obtained based on the constructed power grid current function; the current reactive power can be obtained by multiplying the current voltage RMS value and current RMS value of the power grid. In practical applications, the voltage RMS value and current RMS value in the power grid respectively describe the average effect or equivalent DC value of the voltage and current in the power grid. The voltage RMS value refers to the equivalent DC voltage value generated by the AC voltage in one cycle, and the thermal effect it generates is the same as the thermal effect generated by the corresponding AC voltage in one cycle. The current RMS value represents the equivalent DC current value generated by the AC current in one cycle, and the thermal effect generated by the DC current is the same as the thermal effect generated by the AC current in one cycle. In this example, the reactive power in the power grid is obtained by collecting and calculating the voltage RMS value and voltage RMS value in the power grid, thereby improving the accuracy of obtaining the reactive power in the power grid.

[0071] Furthermore, it is necessary to construct corresponding grid voltage function and grid current function according to the electrical parameters in the grid. Accordingly, as an example, the current grid voltage function and grid current function of the grid are constructed, including:

[0072] Obtain the grid voltage, grid current, voltage zero-crossing point, frequency, and current zero-crossing point of the grid;

[0073] According to the grid voltage and frequency, the grid voltage function is constructed; according to the voltage zero crossing point and the current zero crossing point, the phase angle difference between the voltage and the current is calculated;

[0074] A grid current function is constructed according to the phase angle difference between voltage and current and the grid current.

[0075] Specifically, the sampling device collects electrical parameters in the power grid, and obtains the grid voltage, current voltage, voltage zero crossing point, current zero crossing point and grid frequency; according to the voltage and frequency of the grid, a grid voltage function is constructed, and the grid voltage function is expressed as:

[0076] U ac =U pk *sin(ω*t)

[0077] ω=2πf

[0078] Among them, U ac Indicates the effective value of the voltage of the power grid, U pk represents the maximum voltage of the power grid, ω represents the angular frequency, t represents the time; f represents the frequency of the power grid.

[0079] Next, the phase angle difference between voltage and current is calculated based on the voltage zero-crossing point of the power grid and the current zero-crossing point of the power grid, which is recorded as φ1;

[0080] Then, according to the phase angle difference and the grid current in the grid, a grid current function is constructed; it is expressed as:

[0081] I ac =I pk *sin(ω*t+φ1)

[0082] Among them, I ac Indicates the effective value of the current in the power grid, I pk Indicates the maximum current of the power grid, ω indicates the angular frequency, the calculation formula is consistent with the above, t indicates time, and φ1 indicates the phase angle difference between the voltage and current of the power grid. In this example, the voltage function of the power grid and the current function of the power grid are constructed according to the electrical parameters in the power grid, which improves the accuracy of the voltage function and current function of the power grid.

[0083] Furthermore, the phase angle difference between the voltage and the current is calculated based on the voltage zero crossing point and the current zero crossing point, including:

[0084] Get the time of voltage zero crossing and the time of current zero crossing respectively;

[0085] The phase angle difference between voltage and current is calculated based on the time difference between the voltage zero crossing time and the current zero crossing time.

[0086] The sampling device collects the time corresponding to the voltage zero crossing point and the current zero crossing point in the power grid; then calculates the time difference between the voltage zero crossing point and the current zero crossing point; further, the phase angle difference between the voltage and current phases is calculated based on the time difference; the calculation formula can be expressed as:

[0087] φ1=ω×(t i -t v )

[0088] Among them, φ1 represents the phase difference, ω represents the angular frequency, and t i Indicates the time when the current passes through zero, t v Indicates the time when the voltage crosses zero. In this example, the phase difference between the voltage and current in the power grid is obtained based on the time when the voltage crosses zero and the time when the current crosses zero, which improves the accuracy of calculating the reactive power in the power grid.

[0089] As an example, Figure 5 Schematic diagram of the process of the detection method of the power grid system of this application; Figure 5 As shown, when the inverter is in the grid-connected state, the inverter emits reactive power to the grid; next, the reactive power added by the grid collected by the sampling device is compared with the reactive power emitted by the inverter to see if they are the same in size and direction. If they are the same, it is determined that the sampling device is connected normally, and the inverter exits the detection of the sampling device; if the reactive power added in the grid is inconsistent with the reactive power emitted by the inverter in size and direction, the inverter emits a reactive power of the same size and opposite direction as the first time; next, the reactive power added in the grid is compared again with the reactive power emitted by the inverter at this time to see if they are the same in size and direction. If they are the same, it is determined that the sampling device is connected correctly, and the inverter exits the detection of the sampling device. If they are not the same, the inverter exits the grid-connected state and sends an alarm signal.

[0090] In the detection method of the power grid system provided in this embodiment, the power grid system includes an inverter connected to the power grid and a sampling device for collecting electrical parameters of the power grid, and the sampling device does not pass through a load before connecting to the power grid; by obtaining a preset first reactive power emitted by the inverter in a grid-connected state, and according to the electrical parameters collected by the sampling device before and after the inverter emits the first reactive power, a first increment is obtained, and the first increment represents the difference in reactive power in the power grid after the reactive power is emitted and before the reactive power is emitted; the first reactive power is compared with the first increment, and if the difference between the preset first reactive power emitted and the first increment does not exceed the preset range, it is determined that the connection of the sampling device is correct. The scheme of the present application improves the accuracy of the detection results of the power grid system by comparing the reactive power emitted by the inverter with the increment generated in the power grid due to the emitted reactive power.

[0091] Embodiment 2

[0092] Figure 6 The schematic diagram of the structure of a detection device of a power grid system is exemplarily shown; the power grid system includes an inverter connected to the power grid and a sampling device; wherein the sampling device is used to collect electrical parameters of the power grid, and the sampling device does not pass through a load before being connected to the power grid; Figure 7 As shown, the device comprises:

[0093] An acquisition module 21 is used to acquire a first reactive power generated by the inverter in a grid-connected state;

[0094] The acquisition module 21 is further used to obtain a first increment of reactive power emitted by the power grid before and after the inverter emits the first reactive power according to the electrical parameters collected by the sampling device before and after the inverter emits the first reactive power;

[0095] The comparison module 22 is used to compare and determine that the connection of the sampling device is correct if the difference between the first reactive power and the first increment does not exceed a preset range.

[0096] Specifically, this example does not limit the specific type of sampling device, for example, the sampling device can be a current transformer, an electric meter, etc.; in practical applications, the current transformer mainly collects the current in the power grid; the current transformer can convert the large current on the primary side into a small current on the secondary side for relevant measurements; the electric meter collects the voltage, current, frequency and other related information in the circuit. It should be noted that when the electric meter is used to sample the power grid, the preset reactive power time issued by the inverter must be equal to 10 times the reading cycle of the electric meter, otherwise there will be false alarms and other situations, which will affect the subsequent detection results. In practical applications, the inverter is used to convert DC power sources such as batteries and solar panels into AC power for use by AC loads, such as household appliances and industrial equipment; at the same time, the inverter is an indispensable component of renewable energy systems such as solar photovoltaic power generation and wind power generation; through the inverter, the DC power generated by these renewable energy sources can be converted into AC power, and then injected into the public power grid or used directly. For renewable energy sources such as solar energy and wind energy, the inverter helps to maintain the stability and power balance of the entire power grid system and ensure the reliable operation of the power grid by regulating its output power and fluctuations. In this example, when performing a detection of the power grid system, the inverter is used to detect whether the sampling device in the power grid is connected correctly to ensure that the sampling device can accurately perform power control of the power grid and the normal operation of the power grid system. The solution of this application is applicable to the case where the sampling device is directly connected to the power grid port without passing through any load.

[0097] Specifically, when the inverter is in the grid-connected state, the first reactive power emitted by the inverter is obtained; in practical applications, when the AC power output by the inverter meets the requirements of the public power grid, it will automatically switch to the grid-connected state and connect the electric energy to the public power grid. Reactive power is generated in the AC circuit due to the phase difference between voltage and current. It will not be consumed, but will flow back and forth in the power grid. When the inverter emits the preset first reactive power, it will flow into the power grid. At this time, the first increment is calculated according to the electrical parameters collected by the sampling device; specifically, the sampling device will collect the electrical parameters before the inverter emits the first reactive power, and the electrical parameters after being affected by the emitted first reactive power, and calculate the difference in reactive power in the power grid according to the difference between the electrical parameters before and after the changes, and obtain the corresponding first increment; then, compare the first reactive power with the first increment; if the difference between the two is within the preset difference range, then it is considered that the connection of the power grid sampling device is correct and the sampling device is working normally. In this example, by comparing the preset reactive power emitted by the inverter with the increment in the power grid caused by the reactive power emitted by the inverter, it is determined whether the sampling device is connected correctly and works normally based on the comparison result, thereby improving the accuracy of power grid system detection.

[0098] Further, when comparing the reactive power generated by the inverter with the first increment, it is necessary to compare the magnitude and direction of the reactive power at the same time; accordingly, as an example, the comparison module 22 is also used for:

[0099] comparing the magnitude and direction of the first reactive power and the first increment;

[0100] If the difference between the first reactive power and the first increment does not exceed the preset range, and the reactive power is in the same direction as the first increment, it is determined that the difference between the first reactive power and the first increment does not exceed the preset range.

[0101] Specifically, before the inverter sends out the preset reactive power, the sampling device will collect the electrical parameters in the current power grid, such as voltage, current, frequency and other related parameters; after the inverter sends out the preset first reactive power, the preset reactive power will be transmitted to the power grid, and the sampling device will collect the voltage, current, frequency and other electrical parameters in the power grid at this time; the inverter calculates the increment of reactive power in the power grid according to the electrical parameters before and after sending out the preset first reactive power; if the difference between the first reactive power and the first increment is within the preset error range, and the direction of the first reactive power is consistent with that of the first increment, it is determined that the sampling device is correctly connected and is in a normal working state. In practical applications, since there will be certain fluctuations in the power grid during the working process, it is sufficient to determine that the error between the first reactive power and the first increment is within the preset error range. In this example, by comparing the size and direction of the preset reactive power sent by the inverter, the accuracy of the detection result of the power grid system is further improved. At the same time, by comparing the direction, the reverse connection of the sampling device can be accurately detected.

[0102] Further, when the difference between the preset reactive power emitted by the inverter and the first increment exceeds the preset range, further detection is required; accordingly, as an example, the comparison module 22 is also used for:

[0103] If the difference between the first reactive power and the first increment exceeds a preset range, the inverter is controlled to generate a second reactive power; the second reactive power is the same in magnitude and opposite in direction to the first reactive power;

[0104] Obtaining a second increment of reactive power emitted by the power grid before and after the inverter emits the second reactive power according to electrical parameters collected by the sampling device before and after the inverter emits the second reactive power;

[0105] If the difference between the second reactive power and the second increment does not exceed the preset range, it is determined that the connection of the sampling device is correct; otherwise, it is determined that the connection of the sampling device is incorrect.

[0106] Specifically, when the difference between the first reactive power and the first increment exceeds a preset range, considering that the user's load may have reactive power fluctuations, the inverter is controlled to emit a second reactive power of the same magnitude and opposite direction as the first reactive power; in practical applications, when the load in the power grid system changes, such as the start and stop of the motor, the input and removal of the transformer, etc., reactive power fluctuations will occur. The structure and parameters of the power grid will also affect the distribution and stability of reactive power; for example, the reactive loss of components such as transmission lines and transformers in the power grid, and the switching of reactive compensation equipment such as parallel reactors and capacitors will cause reactive power fluctuations. Similarly, according to the electrical parameters collected by the sampling device before and after the inverter emits the second reactive power, the second increment of the reactive power emitted by the inverter before and after the second reactive power is emitted is obtained; specifically, before the inverter is controlled to emit the second reactive power, the sampling device collects the electrical parameters in the power grid; after the inverter emits the second reactive power, the sampling device collects the electrical parameters in the power grid at this time, and the inverter calculates the second increment of reactive power in the power grid according to the electrical parameters that change before and after the second reactive power is emitted. Afterwards, the difference between the second reactive power and the second increment is compared. If the difference between the second reactive power and the second increment is within the preset range, the sampling device is determined to be correctly connected; otherwise, the sampling device is determined to be incorrectly connected. In this example, taking into account possible load fluctuations in the power grid, when the difference between the preset reactive power emitted for the first time and the reactive power added in the power grid exceeds the preset range, the inverter is controlled to emit a reactive power of the same magnitude and opposite direction as the first time, and then the difference between the reactive power at this time and the increment of the reactive power in the power grid is compared to determine whether the sampling device is correctly connected, thereby further improving the accuracy of power grid system detection.

[0107] Further, when it is detected that the difference between the second reactive power emitted by the inverter and the second increment is still beyond the preset range, it is determined that the sampling device is connected incorrectly; accordingly, as an example, the device further includes: an alarm module 23, which is used to:

[0108] If a connection error of the sampling device is detected, the inverter is controlled to exit the grid-connected state and an alarm signal is issued.

[0109] Specifically, when the inverter emits reactive power of the same magnitude and opposite direction as the first time, the difference between the increment of reactive power in the power grid and the reactive power emitted by the inverter still exceeds the preset range; at this time, it is determined that the sampling device is connected incorrectly and cannot work normally; the inverter exits the grid-connected state and issues a corresponding alarm signal, waiting for maintenance. Specifically, when it is determined that the sampling device is damaged, the inverter will automatically exit the grid-connected mode to avoid causing greater impact on the power grid; after the inverter exits the grid-connected mode, it will immediately issue an alarm signal to notify the operation and maintenance personnel to inspect and repair. At the same time, the inverter will enter the standby state, waiting for the maintenance to be completed and recalibrated before resuming grid-connected operation. In this example, when it is determined that the sampling device is connected incorrectly, the inverter exits the grid-connected state and issues an alarm to wait for maintenance, which ensures the normal operation of the power grid system and reduces the impact of the damage to the sampling device on the power grid system.

[0110] Furthermore, the present application needs to obtain the reactive power generated by the inverter, so as to detect the power grid system according to the comparison between the reactive power generated by the inverter and the increment of the reactive power in the power grid. Accordingly, as an example, the acquisition module 21 is used for:

[0111] The reactive power outputted by the inverter in a grid-connected state according to a preset power limit condition is obtained as the first reactive power.

[0112] Specifically, the reactive power emitted by the inverter will be subject to restrictions in different regions. When the region has strict requirements on the grid-connected power feeding of the inverter, the detection interval can be accelerated to speed up the interval for emitting the preset reactive power to avoid failure of the sampling device; when the region has loose requirements on the grid-connected power feeding of the inverter, the detection interval can be appropriately reduced to reduce the interval for emitting the preset reactive power to avoid excessive reactive power emission causing grid voltage fluctuations. Therefore, the reactive power emitted by the inverter under the corresponding preset power limit conditions can be obtained as the first reactive power of this application. In this example, the reactive power emitted by the inverter at regular intervals under the preset power limit conditions is obtained, which improves the detection efficiency of the power grid system.

[0113] Furthermore, the acquisition module 21 is also used for:

[0114] The inverter is controlled to emit reactive power of a predetermined magnitude and direction, and the reactive power is used as the first reactive power.

[0115] Specifically, the inverter can also be controlled to emit reactive power of preset magnitude and direction, and the reactive power of preset magnitude and direction can be used as the first reactive power of the present application. In this example, by controlling the inverter to emit reactive power of preset magnitude and direction as the first reactive power, the efficiency of obtaining reactive power is improved, and while ensuring the accuracy of the detection results of the power grid system, the detection efficiency of the power grid system is further improved.

[0116] Specifically, the inverter needs to compare the difference between the increment of reactive power in the power grid and the first reactive power before and after the first reactive power is emitted; accordingly, as an example, the acquisition module 21 is also used for:

[0117] Before and after the inverter emits the first reactive power, the current reactive power is calculated according to the current effective value of the voltage and the effective value of the current of the power grid, so as to obtain the reactive power of the power grid before and after the inverter emits the first reactive power;

[0118] The first increment is obtained by difference calculation according to the reactive power of the power grid before and after the inverter generates the first reactive power.

[0119] Specifically, before the inverter emits the first reactive power, the effective value of the voltage and the effective value of the current of the power grid are obtained; the reactive power in the power grid at this time is calculated according to the effective value of the voltage and the effective value of the current at this time, that is, the reactive power in the power grid before the inverter emits the first reactive power. Similarly, after the inverter emits the first reactive power, the effective value of the voltage and the effective value of the current of the power grid are obtained; the reactive power in the power grid at this time is calculated according to the effective value of the voltage and the effective value of the current at this time, that is, the reactive power in the power grid after the inverter emits the first reactive power. The reactive power in the power grid after the first reactive power is emitted is subtracted from the reactive power in the power grid before the first reactive power is emitted to obtain the first increment; the first increment represents the increased reactive power generated in the power grid due to the inverter emitting the preset reactive power. In this example, the increment of the reactive power in the power grid is calculated according to the effective value of the voltage and the effective value of the current of the power grid before and after the inverter in the power grid emits the preset reactive power, thereby improving the accuracy of reactive power detection in the power grid.

[0120] Furthermore, the current reactive power is calculated based on the current voltage and current effective values ​​of the power grid, including:

[0121] Construct the current grid voltage function and grid current function of the grid;

[0122] According to the grid voltage function and the grid current function, the current voltage effective value and current effective value of the grid are calculated;

[0123] Multiply the current effective value of the voltage and the effective value of the current of the power grid to obtain the current reactive power.

[0124] Specifically, when the current reactive power needs to be calculated based on the current voltage RMS value and current RMS value of the power grid, first, the current power grid voltage function and power grid current function need to be constructed; specifically, the corresponding power grid voltage function and power grid current function need to be constructed based on the electrical parameters in the power grid collected by the sampling device. Then, the voltage RMS value is obtained based on the constructed power grid voltage function, and the current RMS value is obtained based on the constructed power grid current function; the current reactive power can be obtained by multiplying the current voltage RMS value and current RMS value of the power grid. In practical applications, the voltage RMS value and current RMS value in the power grid respectively describe the average effect or equivalent DC value of the voltage and current in the power grid. The voltage RMS value refers to the equivalent DC voltage value generated by the AC voltage in one cycle, and the thermal effect it generates is the same as the thermal effect generated by the corresponding AC voltage in one cycle. The current RMS value represents the equivalent DC current value generated by the AC current in one cycle, and the thermal effect generated by the DC current is the same as the thermal effect generated by the AC current in one cycle. In this example, the reactive power in the power grid is obtained by collecting and calculating the voltage RMS value and voltage RMS value in the power grid, thereby improving the accuracy of obtaining the reactive power in the power grid.

[0125] Furthermore, it is necessary to construct corresponding grid voltage function and grid current function according to the electrical parameters in the grid. Accordingly, as an example, the current grid voltage function and grid current function of the grid are constructed, including:

[0126] Obtain the grid voltage, grid current, voltage zero-crossing point, frequency, and current zero-crossing point of the grid;

[0127] According to the grid voltage and frequency, the grid voltage function is constructed; according to the voltage zero crossing point and the current zero crossing point, the phase angle difference between the voltage and the current is calculated;

[0128] A grid current function is constructed according to the phase angle difference between voltage and current and the grid current.

[0129] Specifically, the sampling device collects electrical parameters in the power grid, and obtains the grid voltage, current voltage, voltage zero crossing point, current zero crossing point and grid frequency; according to the voltage and frequency of the grid, a grid voltage function is constructed, and the grid voltage function is expressed as:

[0130] U ac =U pk *sin(ω*t)

[0131] ω=2πf

[0132] Among them, U ac Indicates the effective value of the voltage of the power grid, U pk represents the maximum voltage of the power grid, ω represents the angular frequency, t represents the time; f represents the frequency of the power grid.

[0133] Next, the phase angle difference between voltage and current is calculated based on the voltage zero-crossing point of the power grid and the current zero-crossing point of the power grid, which is recorded as φ1;

[0134] Then, according to the phase angle difference and the grid current in the grid, a grid current function is constructed; it is expressed as:

[0135] I ac =I pk *sin(ω*t+φ1)

[0136] Among them, I ac Indicates the effective value of the current in the power grid, I pk Indicates the maximum current of the power grid, ω indicates the angular frequency, the calculation formula is consistent with the above, t indicates time, and φ1 indicates the phase angle difference between the voltage and current of the power grid. In this example, the voltage function of the power grid and the current function of the power grid are constructed according to the electrical parameters in the power grid, which improves the accuracy of the voltage function and current function of the power grid.

[0137] Furthermore, the phase angle difference between the voltage and the current is calculated based on the voltage zero crossing point and the current zero crossing point, including:

[0138] Get the time of voltage zero crossing and the time of current zero crossing respectively;

[0139] The phase angle difference between voltage and current is calculated based on the time difference between the voltage zero crossing time and the current zero crossing time.

[0140] The sampling device collects the time corresponding to the voltage zero crossing point and the current zero crossing point in the power grid; then calculates the time difference between the voltage zero crossing point and the current zero crossing point; further, the phase angle difference between the voltage and current phases is calculated based on the time difference; the calculation formula can be expressed as:

[0141] φ1=ω×(t i -t v )

[0142] Among them, φ1 represents the phase difference, ω represents the angular frequency, and t i Indicates the time when the current passes through zero, t v Indicates the time when the voltage crosses zero. In this example, the phase difference between the voltage and current in the power grid is obtained based on the time when the voltage crosses zero and the time when the current crosses zero, which improves the accuracy of calculating the reactive power in the power grid.

[0143] The detection device of the power grid system provided in this embodiment, the power grid system includes an inverter connected to the power grid and a sampling device for collecting electrical parameters of the power grid, and the sampling device does not pass through a load before connecting to the power grid; by obtaining a preset first reactive power emitted by the inverter in the grid-connected state, and according to the electrical parameters before and after the inverter emits the first reactive power collected by the sampling device, a first increment is obtained, and the first increment represents the difference in reactive power in the power grid after the reactive power is emitted and before the reactive power is emitted; the first reactive power is compared with the first increment, and if the difference between the preset first reactive power emitted and the first increment does not exceed the preset range, it is determined that the connection of the sampling device is correct. The scheme of the present application improves the accuracy of the detection results of the power grid system by comparing the reactive power emitted by the inverter with the increment generated in the power grid due to the emitted reactive power.

[0144] Embodiment 3

[0145] Figure 7 exemplarily shows a structural schematic diagram of an electronic device, the device comprising:

[0146] The device includes a processor 291 and a memory 292; it may also include a communication interface 293 and a bus 294. The processor 291, the memory 292, and the communication interface 293 may communicate with each other through the bus 294. The communication interface 293 may be used for information transmission. The processor 291 may call the logic instructions in the memory 292 to execute the above-mentioned example method.

[0147] In addition, the logic instructions in the above-mentioned memory 292 can be implemented in the form of software functional units and can be stored in a computer-readable storage medium when sold or used as an independent product.

[0148] The memory 292 is a computer-readable storage medium that can be used to store software programs and computer executable programs, such as program instructions / modules corresponding to the methods in the embodiments of the present application. The processor 291 executes functional applications and data processing by running the software programs, instructions, and modules stored in the memory 292, that is, implementing the methods in the above method examples.

[0149] The memory 292 may include a program storage area and a data storage area, wherein the program storage area may store an operating system and an application required for at least one function; the data storage area may store data created according to the use of the terminal device, etc. In addition, the memory 292 may include a high-speed random access memory and may also include a non-volatile memory.

[0150] In the above embodiments, it should be understood that the processor may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), etc. A general-purpose processor may be a microprocessor or any conventional processor. The steps of the method disclosed in the invention may be directly implemented as being executed by a hardware processor, or may be executed by a combination of hardware and software modules in the processor.

[0151] The memory may include a high-speed memory (Random Access Memory, RAM), and may also include a non-volatile memory (Non-volatile Memory, NVM), such as at least one disk memory.

[0152] 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. For ease of representation, the bus in the drawings of the present application is not limited to only one bus or one type of bus.

[0153] The present application also provides a computer program product, including a computer program, which implements the above method when executed by a processor.

[0154] The present application also provides a computer-readable storage medium, in which computer-executable instructions are stored. When a processor executes the computer-executable instructions, the above method is implemented.

[0155] The above-mentioned 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 disk. The readable storage medium can be any available medium that can be accessed by a general or special-purpose computer.

[0156] An exemplary readable storage medium is coupled to a processor so that the processor can read information from the readable storage medium 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 (Application Specific Integrated Circuits, referred to as: ASIC). Of course, the processor and the readable storage medium can also exist in the device as discrete components.

[0157] The division of units is only a logical function division, and there may be other divisions in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interface, device or unit, which can be electrical, mechanical or other forms.

[0158] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0159] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0160] If the function is implemented in the form of a software functional unit and sold or used as an independent product, it 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, including several instructions for a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the methods of each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc. Various media that can store program codes.

[0161] Those skilled in the art can understand that all or part of the steps of implementing the above-mentioned method embodiments can be completed by hardware related to program instructions. The aforementioned program can be stored in a computer-readable storage medium. When the program is executed, the steps of the above-mentioned method embodiments are executed; and the aforementioned storage medium includes: ROM, RAM, disk or optical disk and other media that can store program codes.

[0162] 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 common knowledge or customary technical means in the art not disclosed by the present invention, are not limited to the precise structure described above and shown in the drawings, and may be modified and changed in various ways without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

Claims

1. A detection method for a power grid system, characterized in that: The power grid system includes an inverter and a sampling device connected to the power grid; wherein the sampling device is used to collect electrical parameters of the power grid, and the sampling device does not pass through a load before being connected to the power grid; the method includes: Acquire a first reactive power generated by the inverter in a grid-connected state; Obtaining, according to the electrical parameters collected by the sampling device before and after the inverter emits the first reactive power, a first increment of reactive power emitted by the power grid before and after the inverter emits the first reactive power; If the difference between the first reactive power and the first increment does not exceed a preset range, it is determined that the connection of the sampling device is correct.

2. The method according to claim 1, characterized in that The method further comprises: comparing the magnitude and direction of the first reactive power and the first increment; If the difference between the first reactive power and the first increment does not exceed a preset range, and the reactive power is in the same direction as the first increment, it is determined that the difference between the first reactive power and the first increment does not exceed a preset range.

3. The method according to claim 1, characterized in that The method further comprises: If the difference between the first reactive power and the first increment exceeds a preset range, the inverter is controlled to emit a second reactive power; the second reactive power is the same in magnitude and opposite in direction to the first reactive power; Obtaining, according to the electrical parameters collected by the sampling device before and after the inverter emits the second reactive power, a second increment of reactive power emitted by the power grid before and after the inverter emits the second reactive power; If the difference between the second reactive power and the second increment does not exceed a preset range, it is determined that the connection of the sampling device is correct; otherwise, it is determined that the connection of the sampling device is incorrect.

4. The method according to claim 3, characterized in that The method further comprises: If a connection error of the sampling device is detected, the inverter is controlled to exit the grid-connected state and send out an alarm signal.

5. The method according to claim 1, characterized in that The obtaining of the first reactive power generated by the inverter in a grid-connected state comprises: The reactive power outputted by the inverter in a grid-connected state according to a preset power limitation condition is obtained as the first reactive power.

6. The method according to claim 1, characterized in that The obtaining of the first reactive power generated by the inverter in a grid-connected state comprises: The inverter is controlled to emit reactive power of a predetermined magnitude and direction, and the reactive power is used as the first reactive power.

7. The method according to any one of claims 1 to 6, characterized in that: The obtaining of a first increment of reactive power emitted by the power grid before and after the inverter emits the first reactive power comprises: Before and after the inverter emits the first reactive power, respectively, calculate the current reactive power according to the current effective value of the voltage and the effective value of the current of the power grid, so as to obtain the reactive power of the power grid before and after the inverter emits the first reactive power; The first increment is obtained by difference calculation according to the reactive power of the power grid before and after the inverter emits the first reactive power.

8. The method according to claim 7, characterized in that The calculating the current reactive power according to the current voltage effective value and current effective value of the power grid comprises: Constructing a current grid voltage function and a grid current function of the grid; Calculating the current voltage and current of the power grid according to the power grid voltage function and the power grid current function; The current reactive power is obtained by multiplying the current effective value of the voltage and the current of the power grid.

9. The method according to claim 8, characterized in that The constructing of the current grid voltage function and grid current function of the grid includes: Obtain the grid voltage, grid current, voltage zero-crossing point, frequency, and current zero-crossing point of the grid; According to the grid voltage and the frequency, construct the grid voltage function; according to the voltage zero-crossing point and the current zero-crossing point, calculate the phase angle difference between the voltage and the current; The grid current function is constructed according to the phase angle difference between the voltage and the current and the grid current.

10. The method according to claim 9, characterized in that The step of calculating the phase angle difference between the voltage and the current according to the voltage zero crossing point and the current zero crossing point comprises: Get the time of voltage zero crossing and the time of current zero crossing respectively; The phase angle difference between the voltage and the current is calculated based on the time difference between the voltage zero-crossing time and the current zero-crossing time.

11. A detection device for a power grid system, characterized in that: The power grid system includes an inverter and a sampling device connected to the power grid; wherein the sampling device is used to collect electrical parameters of the power grid, and the sampling device does not pass through a load before being connected to the power grid; the device includes: An acquisition module, used for acquiring a first reactive power generated by the inverter in a grid-connected state; The acquisition module is further used to obtain a first increment of reactive power emitted by the power grid before and after the inverter emits the first reactive power based on the electrical parameters collected by the sampling device before and after the inverter emits the first reactive power; The comparison module is configured to determine that the connection of the sampling device is correct if the difference between the first reactive power and the first increment does not exceed a preset range.

12. An electronic device, characterized in that: include: A processor, and a memory communicatively connected to the processor; The memory stores computer-executable instructions; The processor executes the computer-executable instructions stored in the memory to implement the method according to any one of claims 1 to 10.

13. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer-executable instructions, which are used to implement the method according to any one of claims 1 to 10 when executed by a processor.

14. A computer program product, characterized in that The invention comprises a computer program, which implements the method according to any one of claims 1 to 10 when being executed by a processor.

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