Impedance scanning test method and device for energy storage system based on grid-connected characteristics

Abstract

The invention discloses an energy storage system impedance scanning test method and device based on grid connection characteristics, and relates to the technical field of electric energy storage systems. Firstly, the energy storage system is accessed to a power grid through the power electronic grid-connected converter, the access process is continuously analyzed, then grid-connected modulation is carried out on the power electronic grid-connected converter, the adjustment capability and response speed of the energy storage system in the power grid are enhanced, then fluctuation detection is carried out on the modulated grid-connected energy storage system, and the fluctuation of the energy storage system is detected. The performance of the grid-connected energy storage system can be optimized by further configuring the grid-connected energy storage system and processing to obtain the impedance scanning test execution parameters, and finally, the impedance scanning test is performed on the configured grid-connected energy storage system in combination with the impedance scanning test execution parameters, and the power stability control is performed on the grid-connected energy storage system. The electrical characteristics of the energy storage system can be comprehensively evaluated, and the stability and safety of the energy storage system in a power grid are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of electric energy storage systems, and in particular to an impedance scanning test method and device for an energy storage system based on grid-connected characteristics. Background Art

[0002] In the field of energy storage system detection technology, as the power system's demand for efficient, stable and sustainable energy supply continues to increase, energy storage technology plays an increasingly important role in power dispatching, load balancing and system stability. In the grid-connected system, the status and performance of energy storage equipment directly affect the safety and reliability of the power grid. The damping characteristics of the energy storage system have an important impact on its grid-connected process and stability. By accurately measuring the impedance response of the energy storage system at different frequencies, the electrical characteristics, performance degradation and potential faults of the energy storage equipment can be effectively identified, thereby improving the power grid's management and monitoring of energy storage equipment.

[0003] The prior art, such as the invention patent announcement with announcement number: CN112467799B, discloses a method and device for grid-connected control of a battery energy storage system. The method includes: in response to the acquired active power and reactive power, performing difference compensation on the active power and reactive power; inputting the active current reference value output by the current controller and the reactive current reference value output by the current controller into the current limit controller based on the charge and discharge control strategy; performing Park transformation on the port current to obtain the real-time value of the active current and the real-time value of the reactive current; inputting the active current difference and the reactive current difference into the PI controller, and obtaining the three-phase voltage reference value based on the Park inverse transformation; comparing the three-phase voltage reference value with the modulation voltage to obtain the modulation wave. The controller is compensated and controlled based on the error value, and the three-phase voltage reference value is compared with the modulation voltage to obtain the modulation wave, thereby controlling the switching device of the power converter.

[0004] Prior art, such as the invention patent announcement with announcement number: CN115986797B, discloses a method, device and system for detecting the grid-connected performance of an electrochemical energy storage system for a new energy station based on multi-point synchronous testing. The method, device and system belong to the field of new energy stations and are used to solve the problem that blindly performing grid-connected operations without analyzing the compatibility of the energy storage system and the distribution network reduces the success rate of grid-connected operations. The method comprises an energy storage determination module, a power quality analysis module, an intelligent grid-connected module and a simulation analysis module. The power quality analysis module is used to analyze the energy storage quality of the electrochemical energy storage system, the energy storage determination module is used to determine the energy storage quality of the electrochemical energy storage system, the simulation analysis module is used to simulate and analyze the working state of the electrochemical energy storage system after grid-connection, and the intelligent grid-connected module is used to intelligently connect the electrochemical energy storage system to the distribution network.

[0005] Combined with the above scheme, it is found that in the current field of energy storage system grid-connected technology, usually only power compensation and grid-connected adaptability are analyzed. However, there will be problems with grid instability when the energy storage system is connected to the grid, which will cause the data collection during the impedance scanning test of the energy storage system to be disturbed by grid fluctuations. At the same time, the interference of the grid also leads to the grid-connected energy storage system. There are requirements for the level and accuracy of the actual impedance scanning test. The current technology only analyzes power compensation and grid-connected adaptability, which not only affects the accuracy and stability of the test results, but also fails to truly reflect the dynamic response characteristics of the energy storage system. It may also lead to problems such as increased grid power fluctuations and harmonic distortion, affecting the safety and reliability of the entire power system. Summary of the invention

[0006] In view of the deficiencies in the prior art, the present invention provides an impedance scanning test method and device for an energy storage system based on grid-connected characteristics, which can effectively solve the problems involved in the above-mentioned background technology.

[0007] To achieve the above objectives, the first aspect of the present invention is implemented through the following technical solutions: an impedance scanning test method for an energy storage system based on grid-connected characteristics, including connecting the energy storage system to the power grid through a power electronic grid-connected converter, obtaining the grid-connected characteristic parameters of the energy storage system by continuously analyzing the connection process, and then grid-connected modulation of the power electronic grid-connected converter.

[0008] The modulated grid-connected energy storage system is subjected to fluctuation detection, and then the grid fluctuation result of the grid-connected energy storage system is obtained by analysis. The grid-connected energy storage system is configured according to the grid fluctuation result of the grid-connected energy storage system, and the impedance scanning test execution parameters are obtained by processing, and the impedance scanning test start signal is sent at the same time.

[0009] The central controller receives the impedance scanning test start signal, performs an impedance scanning test on the configured grid-connected energy storage system in combination with the impedance scanning test execution parameters, obtains the damping characteristic information of the grid-connected energy storage system, and sends the damping characteristic information of the grid-connected energy storage system to the central control platform.

[0010] The central control platform receives the damping characteristic information of the grid-connected energy storage system, performs power stability control on the grid-connected energy storage system, and sends the control results to the mobile terminal for display.

[0011] Furthermore, the grid-connected modulation of the power electronic grid-connected converter is specifically carried out as follows: the grid-connected characteristic parameters of the energy storage system include the frequency fluctuation coefficient of the power grid within a preset monitoring period, the number of current harmonic distortions of the power grid, the electromagnetic interference coefficient of the energy storage system and the average charging and discharging efficiency of the energy storage system.

[0012] The grid-connected characteristic value of the energy storage system is obtained based on the grid-connected characteristic parameter processing of the energy storage system. The grid-connected characteristic value of the energy storage system is used to quantify the stability of the process of the energy storage system being connected to the power grid.

[0013] The output power adjustment value of the power electronic grid-connected converter is obtained by matching the grid-connected characteristic value of the energy storage system, the output power of the current power electronic grid-connected converter is added to the output power adjustment value of the power electronic grid-connected converter to obtain the output power target execution value of the power electronic grid-connected converter, and the power electronic grid-connected converter is grid-connected modulated according to the output power target execution value of the power electronic grid-connected converter.

[0014] Furthermore, the fluctuation detection is performed on the modulated grid-connected energy storage system, and the specific process is: the fluctuation detection is performed on the modulated grid-connected energy storage system to obtain the fluctuation detection data of the grid-connected energy storage system, and the fluctuation detection data of the grid-connected energy storage system includes the voltage fluctuation coefficient, frequency fluctuation coefficient, phase shift coefficient and current peak value of the grid-connected energy storage system within a preset fluctuation monitoring period.

[0015] A comprehensive analysis is performed on the fluctuation detection data of the grid-connected energy storage system to obtain a fluctuation detection evaluation value of the grid-connected energy storage system, and the fluctuation detection evaluation value of the grid-connected energy storage system is used to comprehensively quantify the fluctuation degree of the grid-connected energy storage system.

[0016] Furthermore, the analysis obtains the grid fluctuation result of the grid-connected energy storage system, and the specific process is: the grid fluctuation result of the grid-connected energy storage system includes abnormal grid fluctuation and normal grid fluctuation.

[0017] The fluctuation detection assessment threshold of the grid-connected energy storage system stored in the impedance scanning test database is extracted, and the fluctuation detection assessment value of the grid-connected energy storage system is compared with the fluctuation detection assessment threshold of the grid-connected energy storage system. If the fluctuation detection assessment value of the grid-connected energy storage system is higher than the fluctuation detection assessment threshold of the grid-connected energy storage system, the grid fluctuation result of the grid-connected energy storage system is marked as abnormal grid fluctuation; otherwise, the grid fluctuation result of the grid-connected energy storage system is marked as normal grid fluctuation.

[0018] Furthermore, the grid-connected energy storage system is configured according to the grid fluctuation result of the grid-connected energy storage system. The specific process is: extracting the grid fluctuation result of the grid-connected energy storage system, if the grid fluctuation result of the grid-connected energy storage system is that the grid fluctuation is normal, then continuing to configure the grid-connected energy storage system with the current phase-locked loop integral gain of the grid-connected energy storage system.

[0019] If the grid fluctuation result of the grid-connected energy storage system is abnormal grid fluctuation, the current phase-locked loop integral gain of the grid-connected energy storage system is added to the set phase-locked loop integral gain supplement value of the grid-connected energy storage system to obtain the phase-locked loop integral gain target achievement value of the grid-connected energy storage system, and the current phase-locked loop integral gain of the grid-connected energy storage system is increased to the phase-locked loop integral gain target achievement value of the grid-connected energy storage system for configuration.

[0020] Furthermore, the processing obtains the impedance scanning test execution parameters and sends the impedance scanning test start signal at the same time. The specific process is: extracting the grid fluctuation result of the grid-connected energy storage system, if the grid fluctuation result of the grid-connected energy storage system is that the grid fluctuation is normal, then setting the impedance scanning test standard parameters as the impedance scanning test execution parameters.

[0021] If the grid fluctuation result of the grid-connected energy storage system is abnormal grid fluctuation, the difference between the fluctuation detection evaluation value of the grid-connected energy storage system and the fluctuation detection evaluation threshold of the grid-connected energy storage system is recorded as the impedance scanning test control value, and the impedance scanning test execution parameters are obtained according to the impedance scanning test control value matching.

[0022] The impedance scanning test execution parameters include the scanning frequency of the impedance scanning test, the injection signal amplitude of the impedance scanning test and the sampling frequency of the impedance scanning test.

[0023] Furthermore, the impedance scanning test is performed on the configured grid-connected energy storage system in combination with the impedance scanning test execution parameters. The specific process is as follows: the central controller adjusts the impedance scanning test parameters of the energy storage system impedance scanning test device to the impedance scanning test execution parameters, and the impedance scanning test is performed on the configured grid-connected energy storage system by the energy storage system impedance scanning test device to obtain the impedance scanning test parameters of the grid-connected energy storage system. The impedance scanning test parameters of the grid-connected energy storage system include the actual injection signal amplitude of the impedance scanning test within a preset scanning monitoring period, the environmental deviation coefficient of the impedance scanning test, the impedance amplitude fluctuation coefficient of the grid-connected energy storage system, and the voltage fluctuation coefficient of the grid-connected energy storage system.

[0024] Based on the impedance scanning test parameter processing of the grid-connected energy storage system, a damping characteristic analysis index value of the grid-connected energy storage system is obtained, and the damping characteristic analysis index value of the grid-connected energy storage system is used to quantify the ability of the grid-connected energy storage system to suppress grid oscillation.

[0025] Furthermore, the damping characteristic information of the grid-connected energy storage system is obtained by specifically importing the damping characteristic analysis index value of the grid-connected energy storage system into the damping characteristic analysis model to obtain the damping characteristic information of the grid-connected energy storage system.

[0026] The damping characteristic analysis index value of the grid-connected energy storage system is marked as .

[0027] The damping characteristic analysis first threshold and the damping characteristic analysis second threshold in the statistical damping characteristic analysis model are respectively marked as , .

[0028] After the damping characteristic analysis model is processed, if , the damping characteristic information of the grid-connected energy storage system is marked as normal damping characteristics.

[0029] like , the damping characteristic information of the grid-connected energy storage system is marked as abnormal damping characteristics.

[0030] like , the damping characteristic information of the grid-connected energy storage system is marked as a damping characteristic fault.

[0031] Furthermore, the power stability control of the grid-connected energy storage system is specifically carried out as follows: extracting damping characteristic information of the grid-connected energy storage system; if the damping characteristic information of the grid-connected energy storage system indicates that the damping characteristic is normal, continuing to perform power stability control with the current operation mode of the grid-connected energy storage system; if the damping characteristic information of the grid-connected energy storage system indicates that the damping characteristic is abnormal, adjusting the current operation mode of the grid-connected energy storage system to the frequency regulation mode; if the damping characteristic information of the grid-connected energy storage system indicates that the damping characteristic is faulty, adjusting the current operation mode of the grid-connected energy storage system to the frequency and voltage regulation mode.

[0032] The second aspect of the present invention provides an apparatus for an impedance scanning test method for an energy storage system based on grid-connected characteristics, further comprising: a processor, and a memory and a network interface connected to the processor; the network interface is connected to a non-volatile memory in a server; when the processor is running, it retrieves a computer program from the non-volatile memory through the network interface, and runs the computer program through the memory to execute the above-mentioned impedance scanning test method for an energy storage system based on grid-connected characteristics.

[0033] The present invention has the following beneficial effects:

[0034] (1) The present invention provides an impedance scanning test method for an energy storage system based on grid-connected characteristics. First, the process of connecting the energy storage system to the grid is continuously analyzed, and then the power electronic grid-connected converter is modulated for grid connection, which helps to improve the stability of the system connection process. Then, the grid-connected energy storage system is subjected to fluctuation detection and configured for the grid-connected energy storage system, which helps to improve the overall performance and response speed of the energy storage system. Finally, the grid-connected energy storage system is subjected to power stability control, which can enhance the reliability of the energy storage system in the grid.

[0035] (2) The present invention can optimize the control method of the grid-connected energy storage system by processing the impedance scanning test execution parameters, reduce the power fluctuation and harmonic distortion caused by the grid fluctuation, and improve the safety and reliability of the power system. According to the grid fluctuation results of the grid-connected energy storage system, the impedance scanning test execution parameters are analyzed and obtained, which can improve the level and accuracy of the actual impedance scanning test and reduce the influence of the grid fluctuation interference on the data acquisition in the impedance scanning test process of the energy storage system.

[0036] (3) The present invention can ensure that the energy storage system adjusts its output power according to the real-time status of the power grid when it is connected to the power grid by performing grid-connected modulation on the power electronic grid-connected converter, thereby improving the compatibility and response speed of the system, reducing the impact of grid fluctuations on the energy storage system, and effectively suppressing the negative impact caused by grid fluctuations or changes in the state of the energy storage system, thereby ensuring the stability and reliability of power output and reducing the occurrence of grid failures.

[0037] (4) The present invention configures the grid-connected energy storage system according to the grid fluctuation results of the grid-connected energy storage system, thereby realizing real-time monitoring and dynamic adjustment of grid fluctuations, facilitating rapid response to grid anomalies, and reducing the impact of grid fluctuations on the impedance scanning test process of the energy storage system. When abnormal grid fluctuations are detected, the energy storage system will automatically adjust the phase-locked loop integral gain to enhance the adaptability of the system and effectively reduce the negative impact of fluctuations on the grid.

[0038] (5) The present invention performs power stability control on the grid-connected energy storage system by receiving the damping characteristic information of the grid-connected energy storage system, thereby ensuring that the system can still operate stably under various circumstances. This can not only improve the response capability of the grid-connected energy storage system to load fluctuations or emergencies, but also reduce power supply interruptions caused by abnormalities of the grid-connected energy storage system. By timely adjusting the operation mode of the energy storage system, accurate and stable control of the power system can be achieved, which helps to improve the overall anti-interference capability of the grid-connected energy storage system.

[0039] Of course, any product implementing the present invention does not necessarily need to achieve all of the advantages described above at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a schematic diagram of the method flow of the present invention. DETAILED DESCRIPTION

[0041] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] See also Figure 1 As shown, the first aspect of an embodiment of the present invention provides a technical solution: an impedance scanning test method for an energy storage system based on grid-connected characteristics, comprising connecting the energy storage system to the power grid through a power electronic grid-connected converter, obtaining grid-connected characteristic parameters of the energy storage system by continuously analyzing the connection process, and then performing grid-connected modulation on the power electronic grid-connected converter.

[0043] The modulated grid-connected energy storage system is subjected to fluctuation detection, and then the grid fluctuation result of the grid-connected energy storage system is obtained by analysis. The grid-connected energy storage system is configured according to the grid fluctuation result of the grid-connected energy storage system, and the impedance scanning test execution parameters are obtained by processing, and the impedance scanning test start signal is sent at the same time.

[0044] It needs to be explained that the energy storage system refers to an independent system before being connected to the power grid, and the grid-connected energy storage system refers to the system after the energy storage system is connected to the power grid through a power electronic grid-connected converter, which can carry out bidirectional flow of energy according to the dispatch of the power grid.

[0045] The central controller receives the impedance scanning test start signal, performs an impedance scanning test on the configured grid-connected energy storage system in combination with the impedance scanning test execution parameters, obtains the damping characteristic information of the grid-connected energy storage system, and sends the damping characteristic information of the grid-connected energy storage system to the central control platform.

[0046] The central control platform receives the damping characteristic information of the grid-connected energy storage system, performs power stability control on the grid-connected energy storage system, and sends the control results to the mobile terminal for display.

[0047] Specifically, the power electronic grid-connected converter is grid-connected modulated, and the specific process is: the grid-connected characteristic parameters of the energy storage system include the frequency fluctuation coefficient of the power grid within a preset monitoring period, the number of current harmonic distortions of the power grid, the electromagnetic interference coefficient of the energy storage system, and the average charging and discharging efficiency of the energy storage system.

[0048] It should be noted that the frequency fluctuation coefficient of the power grid reflects the stability of the power grid frequency within the preset monitoring period. The power quality analyzer is used to measure the power grid frequency at multiple times within the preset monitoring period, and then the standard deviation and average value of the power grid frequency within the preset monitoring period are obtained. The ratio of the standard deviation and the average value of the power grid frequency within the preset monitoring period is used as the frequency fluctuation coefficient of the power grid. The harmonic distortion number of the power grid current reflects the degree of deviation between the current waveform in the power grid and the ideal sinusoidal waveform. The power quality analyzer can be used to measure the harmonic distortion number of the power grid current. The electromagnetic interference coefficient of the energy storage system reflects the electromagnetic interference intensity generated by the energy storage system during operation. The electromagnetic interference signal power generated by the energy storage system can be measured by an electromagnetic interference test receiver. The ratio of the electromagnetic interference signal power to the set reference signal power is used as the electromagnetic interference coefficient of the energy storage system. The average charge and discharge efficiency of the energy storage system reflects the average energy conversion efficiency of the energy storage system during charge and discharge operations within the preset monitoring period. The charge and discharge efficiency of the energy storage system at multiple times within the preset monitoring period can be measured by a data acquisition system, and the average charge and discharge efficiency of the energy storage system can be obtained by taking the average value.

[0049] The grid-connected characteristic value of the energy storage system is obtained based on the grid-connected characteristic parameter processing of the energy storage system. The grid-connected characteristic value of the energy storage system is used to quantify the stability of the process of the energy storage system being connected to the power grid.

[0050] In this embodiment, the grid-connected characteristic value of the energy storage system can be obtained by the following analysis method, and the specific analysis conditions are as follows:

[0051] ;

[0052] In the formula, represents the grid-connected characteristic value of the energy storage system, represents the frequency fluctuation coefficient of the power grid, Indicates the grid-connected characteristic correction factor corresponding to the set frequency fluctuation coefficient, Indicates the number of current harmonic distortions in the power grid. Indicates the set limit current harmonic distortion order, Indicates the grid-connected characteristic correction factor corresponding to the set current harmonic distortion order. represents the electromagnetic interference coefficient of the energy storage system, Indicates the grid-connected characteristic correction factor corresponding to the set electromagnetic interference coefficient, Represents the average charging and discharging efficiency of the energy storage system, It represents the grid-connected characteristic correction factor corresponding to the set unit charge and discharge efficiency, and e represents a natural constant.

[0053] It should be added that, in this embodiment, the grid-connected characteristic correction factor corresponding to the preset frequency fluctuation coefficient, the grid-connected characteristic correction factor corresponding to the current harmonic distortion order, the grid-connected characteristic correction factor corresponding to the electromagnetic interference coefficient and the grid-connected characteristic correction factor corresponding to the unit charge and discharge efficiency are obtained from the impedance scanning test database.

[0054] It should be explained that the grid-connected characteristic correction factors corresponding to the frequency fluctuation coefficient, the number of current harmonic distortion, the electromagnetic interference coefficient and the unit charge and discharge efficiency are respectively used to adjust the importance of the frequency fluctuation coefficient of the power grid, the number of current harmonic distortion of the power grid, the electromagnetic interference coefficient of the energy storage system and the average charge and discharge efficiency of the energy storage system in the process of analyzing and obtaining the grid-connected characteristic values ​​of the energy storage system. For example, there is a pre-set mapping relationship between the grid-connected characteristic parameters of the energy storage system and the corresponding grid-connected characteristic correction factors in the impedance scanning test database. The pre-set mapping relationship can be used to match the real-time grid-connected characteristic correction factors corresponding to the grid-connected characteristic parameters of the energy storage system. The frequency fluctuation coefficient of the power grid, the number of current harmonic distortion of the power grid, the electromagnetic interference coefficient of the energy storage system and the average charge and discharge efficiency of the energy storage system are matched with the pre-set mapping relationship respectively to obtain the grid-connected characteristic correction factors corresponding to the frequency fluctuation coefficient, the number of current harmonic distortion, the electromagnetic interference coefficient and the unit charge and discharge efficiency.

[0055] In this implementation scheme, there is a correlation between the frequency fluctuation coefficient of the power grid, the number of current harmonic distortions of the power grid, the electromagnetic interference coefficient of the energy storage system and the average charging and discharging efficiency of the energy storage system, and they do not exist independently. For example, frequency fluctuations will affect the operating state of the power grid. An increase in the frequency fluctuation coefficient may be accompanied by an increase in the number of current harmonic distortions. The frequency fluctuation of the power grid may affect the working mode of the energy storage system. When the frequency fluctuation coefficient is large, the energy storage system may be frequently adjusted to maintain the stability of the power grid, which will aggravate the electromagnetic interference in the energy storage system and increase the electromagnetic interference coefficient of the energy storage system. An excessively high electromagnetic interference coefficient may increase equipment losses, thereby reducing the charging and discharging efficiency of the system. The low charging and discharging efficiency of the energy storage system may increase the generation of current harmonics and the number of current harmonic distortions. A comprehensive analysis is performed to obtain the grid-connected characteristic value of the energy storage system, which can improve the grid-connected regulation capability of the energy storage system.

[0056] The output power adjustment value of the power electronic grid-connected converter is obtained by matching the grid-connected characteristic value of the energy storage system, the output power of the current power electronic grid-connected converter is added to the output power adjustment value of the power electronic grid-connected converter to obtain the output power target execution value of the power electronic grid-connected converter, and the power electronic grid-connected converter is grid-connected modulated according to the output power target execution value of the power electronic grid-connected converter.

[0057] It should be noted that the output power regulation value of the power electronic grid-connected converter is obtained according to the matching of the grid-connected characteristic value of the energy storage system. The specific process is to match the grid-connected characteristic value of the energy storage system with the output power regulation value of the power electronic grid-connected converter corresponding to the grid-connected characteristic value interval of each energy storage system stored in the impedance scanning test database, and count the output power regulation value of the power electronic grid-connected converter corresponding to the interval where the grid-connected characteristic value of the energy storage system is located, which is recorded as the output power regulation value of the power electronic grid-connected converter.

[0058] It needs to be explained that the analysis of the grid-connected characteristic parameters of the energy storage system can reflect the stability of the energy storage system in the process of connecting to the grid. If the stability of the energy storage system in the process of connecting to the grid is poor, subsequent connection with the original default output power of the power electronic grid-connected converter may affect the normal operation of the grid and the performance of electrical equipment. Therefore, it is necessary to modulate the power electronic grid-connected converter in combination with the grid-connected characteristic value of the energy storage system. The larger the grid-connected characteristic value of the energy storage system, the better the stability of the energy storage system in the process of connecting to the grid, and the smaller the output power adjustment value of the matched power electronic grid-connected converter. The output power target execution value of the power electronic grid-connected converter refers to the adjustment target value of the output power of the power electronic grid-connected converter.

[0059] Specifically, fluctuation detection is performed on the modulated grid-connected energy storage system, and the specific process is: fluctuation detection is performed on the modulated grid-connected energy storage system to obtain fluctuation detection data of the grid-connected energy storage system, and the fluctuation detection data of the grid-connected energy storage system includes the voltage fluctuation coefficient, frequency fluctuation coefficient, phase shift coefficient and current peak value of the grid-connected energy storage system within a preset fluctuation monitoring period.

[0060] It should be noted that the voltage fluctuation coefficient of the grid-connected energy storage system reflects the degree of voltage fluctuation in the grid-connected energy storage system. A voltage sensor can be used to measure the voltage of the grid-connected energy storage system at multiple times within a preset fluctuation monitoring period, and then the ratio of the standard deviation and the average value of the voltage of the grid-connected energy storage system is obtained as the voltage fluctuation coefficient of the grid-connected energy storage system. The frequency fluctuation coefficient of the grid-connected energy storage system reflects the impact of the grid-connected energy storage system on the stability of the grid frequency during the charging and discharging process. A power quality analyzer can be used to measure the frequency of the grid-connected energy storage system at multiple times within a preset fluctuation monitoring period, and then the standard deviation and the average value of the frequency of the grid-connected energy storage system within the preset fluctuation monitoring period are obtained. The ratio of the standard deviation to the average value is used as the frequency fluctuation coefficient of the grid-connected energy storage system. The phase shift coefficient of the grid-connected energy storage system reflects the degree of change in the current phase of the energy storage system during the process of being connected to the grid. The phase angle of the output current of the energy storage system and the phase angle of the grid current can be measured by a phase meter. The absolute value of the difference between the phase angle of the output current of the energy storage system and the phase angle of the grid current is de-united and obtained as the phase shift coefficient of the grid-connected energy storage system. The current peak value of the grid-connected energy storage system reflects the maximum current value generated by the energy storage system during the grid-connected process. A current sensor can be used to measure the current waveform of the grid-connected energy storage system within a preset fluctuation monitoring period, and the current value at the peak point of the current waveform is found as the current peak value.

[0061] A comprehensive analysis is performed on the fluctuation detection data of the grid-connected energy storage system to obtain a fluctuation detection evaluation value of the grid-connected energy storage system, and the fluctuation detection evaluation value of the grid-connected energy storage system is used to comprehensively quantify the fluctuation degree of the grid-connected energy storage system.

[0062] In this embodiment, the fluctuation detection evaluation value of the grid-connected energy storage system can be obtained by the following analysis method, and the specific analysis conditions are as follows:

[0063] ;

[0064] In the formula, represents the fluctuation detection evaluation value of the grid-connected energy storage system, Represents the voltage fluctuation coefficient of the grid-connected energy storage system, Indicates the fluctuation detection evaluation factor corresponding to the set voltage fluctuation coefficient, Represents the frequency fluctuation coefficient of the grid-connected energy storage system, Indicates the fluctuation detection evaluation factor corresponding to the set frequency fluctuation coefficient, Represents the phase shift coefficient of the grid-connected energy storage system, Indicates the fluctuation detection evaluation factor corresponding to the set phase shift coefficient, Indicates the peak current of the grid-connected energy storage system. Indicates the set reference current peak value, Indicates the fluctuation detection evaluation factor corresponding to the set unit current.

[0065] It should be noted that using the hyperbolic tangent function to compress the input voltage fluctuation coefficient helps to avoid extreme situations where the input is too large or too small. The exponential function helps to highlight the importance of larger values ​​of the frequency fluctuation coefficient. The inverse hyperbolic cosine operation is performed on the addition result of the voltage fluctuation coefficient and the frequency fluctuation coefficient after nonlinear processing, which can be used to compress the value range and convert the input value into a smoother result. Through this function nesting method, the fluctuation detection evaluation value can be gradually affected, and each factor can be processed according to importance and complexity to avoid excessive influence of a single factor, thereby achieving accurate evaluation of the fluctuation of the grid-connected energy storage system.

[0066] It should be added that, in this embodiment, the fluctuation detection evaluation factor corresponding to the preset voltage fluctuation coefficient, the fluctuation detection evaluation factor corresponding to the frequency fluctuation coefficient, the fluctuation detection evaluation factor corresponding to the phase shift coefficient and the fluctuation detection evaluation factor corresponding to the unit current are obtained from the impedance scanning test database.

[0067] It needs to be explained that the voltage fluctuation coefficient, frequency fluctuation coefficient, phase shift coefficient and fluctuation detection evaluation factor corresponding to the unit current are respectively used to adjust the importance of the voltage fluctuation coefficient, frequency fluctuation coefficient, phase shift coefficient and current peak value of the grid-connected energy storage system in the process of analyzing and obtaining the fluctuation detection evaluation value of the grid-connected energy storage system. For example, there is a pre-set mapping relationship between the fluctuation detection data of the grid-connected energy storage system and the corresponding fluctuation detection evaluation factor in the impedance scanning test database. The fluctuation detection evaluation factor corresponding to the real-time fluctuation detection data of the grid-connected energy storage system can be matched through the pre-set mapping relationship. The voltage fluctuation coefficient, frequency fluctuation coefficient, phase shift coefficient and current peak value of the grid-connected energy storage system are matched with the pre-set mapping relationship respectively to obtain the voltage fluctuation coefficient, frequency fluctuation coefficient, phase shift coefficient and fluctuation detection evaluation factor corresponding to the unit current.

[0068] In this implementation scheme, the voltage fluctuation coefficient, frequency fluctuation coefficient, phase shift coefficient and current peak of the grid-connected energy storage system are correlated and do not exist independently. For example, the voltage fluctuation coefficient will be affected by the phase difference between the energy storage system and the power grid. If the phase shift coefficient is large, it may cause more severe voltage fluctuations and increase the voltage fluctuation coefficient, affecting the stability of the power grid. Frequency fluctuations usually reflect the instability of the power grid load, and the appearance of current peaks may aggravate frequency fluctuations. The increase in current peaks may affect voltage fluctuations. Comprehensive analysis can be used to obtain the fluctuation detection evaluation value of the grid-connected energy storage system, which can understand the impact of the energy storage system on the stability of the power grid, and provide data support for the improvement of the grid-connected energy storage system.

[0069] Specifically, the power grid fluctuation result of the grid-connected energy storage system is analyzed and obtained, and the specific process is: the power grid fluctuation result of the grid-connected energy storage system includes abnormal power grid fluctuation and normal power grid fluctuation.

[0070] The fluctuation detection assessment threshold of the grid-connected energy storage system stored in the impedance scanning test database is extracted, and the fluctuation detection assessment value of the grid-connected energy storage system is compared with the fluctuation detection assessment threshold of the grid-connected energy storage system. If the fluctuation detection assessment value of the grid-connected energy storage system is higher than the fluctuation detection assessment threshold of the grid-connected energy storage system, the grid fluctuation result of the grid-connected energy storage system is marked as abnormal grid fluctuation; otherwise, the grid fluctuation result of the grid-connected energy storage system is marked as normal grid fluctuation.

[0071] Specifically, the grid-connected energy storage system is configured according to the grid fluctuation result of the grid-connected energy storage system. The specific process is: extract the grid fluctuation result of the grid-connected energy storage system, if the grid fluctuation result of the grid-connected energy storage system is that the grid fluctuation is normal, then continue to configure the grid-connected energy storage system with the current phase-locked loop integral gain of the grid-connected energy storage system.

[0072] If the grid fluctuation result of the grid-connected energy storage system is abnormal grid fluctuation, the current phase-locked loop integral gain of the grid-connected energy storage system is added to the set phase-locked loop integral gain supplement value of the grid-connected energy storage system to obtain the phase-locked loop integral gain target achievement value of the grid-connected energy storage system, and the current phase-locked loop integral gain of the grid-connected energy storage system is increased to the phase-locked loop integral gain target achievement value of the grid-connected energy storage system for configuration.

[0073] It needs to be explained that the phase-locked loop integral gain is used to reduce steady-state errors and improve the phase accuracy of the phase-locked loop. By increasing the phase-locked loop integral gain of the grid-connected energy storage system, the grid frequency and phase can be better tracked, reducing system instability caused by grid fluctuations. At the same time, the system's response speed to grid fluctuations can be improved.

[0074] It should be noted that, in this embodiment, after the grid-connected energy storage system is configured, the fluctuation detection data of the grid-connected energy storage system will be continuously analyzed, and then continuously configured until the grid fluctuation result of the grid-connected energy storage system obtained by analysis is that the grid fluctuation is normal.

[0075] Specifically, the impedance scanning test execution parameters are processed and the impedance scanning test start signal is sent at the same time. The specific process is: extracting the grid fluctuation result of the grid-connected energy storage system. If the grid fluctuation result of the grid-connected energy storage system is normal, the impedance scanning test standard parameters are set as the impedance scanning test execution parameters.

[0076] If the grid fluctuation result of the grid-connected energy storage system is abnormal grid fluctuation, the difference between the fluctuation detection evaluation value of the grid-connected energy storage system and the fluctuation detection evaluation threshold of the grid-connected energy storage system is recorded as the impedance scanning test control value, and the impedance scanning test execution parameters are obtained according to the impedance scanning test control value matching.

[0077] It should be noted that the impedance scanning test execution parameters are obtained according to the impedance scanning test control value matching. The specific process is to match the impedance scanning test control value with the impedance scanning test execution parameters corresponding to each impedance scanning test control value interval stored in the impedance scanning test database, and count the impedance scanning test execution parameters corresponding to the interval in which the impedance scanning test control value is located, which are recorded as the impedance scanning test execution parameters.

[0078] It needs to be explained that the analysis of the fluctuation detection data of the grid-connected energy storage system can reflect the degree of fluctuation of the grid-connected energy storage system. If the fluctuation of the grid-connected energy storage system is large, subsequent testing with the original default impedance scanning test execution parameters may lead to inaccurate impedance scanning test results. Therefore, it is necessary to modulate the impedance scanning test execution parameters in combination with the fluctuation detection evaluation value of the grid-connected energy storage system. The larger the impedance scanning test control value, the worse the stability of the grid-connected energy storage system. The scanning frequency needs to be reduced to avoid introducing more interference when the system fluctuates greatly. The amplitude of the injected signal needs to be reduced to prevent excessive impact on the system. At the same time, the sampling frequency needs to be increased to more accurately capture the dynamic changes of the system. Therefore, the smaller the scanning frequency and injection signal amplitude of the matched impedance scanning test, the larger the sampling frequency.

[0079] The impedance scanning test execution parameters include the scanning frequency of the impedance scanning test, the injection signal amplitude of the impedance scanning test and the sampling frequency of the impedance scanning test.

[0080] It should be added that adjusting the scanning frequency of the impedance scanning test can improve the accuracy of the test results, optimize the test time, and reduce the possibility of resonance points. Adjusting the injection signal amplitude of the impedance scanning test can prevent system overload, protect equipment and improve safety. Different test stages may require different signal amplitudes. Adjusting the injection signal amplitude can better meet the test requirements. Adjusting the sampling frequency of the impedance scanning test can increase the resolution of the data, better capture signal changes, improve the adaptability of the test, and make the test results more accurate.

[0081] It should be explained that the scanning frequency of the impedance scanning test refers to the frequency of the test signal injected into the system when performing the impedance scanning test, and the sampling frequency of the impedance scanning test refers to the frequency used to collect the system response signal when performing the impedance scanning test.

[0082] Specifically, an impedance scanning test is performed on the configured grid-connected energy storage system in combination with the impedance scanning test execution parameters. The specific process is: the central controller adjusts the impedance scanning test parameters of the energy storage system impedance scanning test device to the impedance scanning test execution parameters, and the impedance scanning test is performed on the configured grid-connected energy storage system by the energy storage system impedance scanning test device to obtain the impedance scanning test parameters of the grid-connected energy storage system. The impedance scanning test parameters of the grid-connected energy storage system include the actual injection signal amplitude of the impedance scanning test within a preset scanning monitoring period, the environmental deviation coefficient of the impedance scanning test, the impedance amplitude fluctuation coefficient of the grid-connected energy storage system, and the voltage fluctuation coefficient of the grid-connected energy storage system.

[0083] It should be noted that the actual injection signal amplitude of the impedance scanning test reflects the signal amplitude applied to the system during the test. The actual injection signal amplitude of the impedance scanning test can be measured by a signal generator. The environmental deviation coefficient of the impedance scanning test reflects the degree of influence of environmental factors (such as temperature, humidity and pressure) on the test results during the impedance scanning test. Environmental monitoring equipment (such as thermometers, hygrometers and manometers) are used to measure environmental parameters (such as temperature, humidity and pressure). The absolute value of the difference between the measured environmental parameters and the set environmental parameter standard value is de-united to obtain the environmental parameter deviation value. The value obtained by averaging the environmental parameter deviation value is used as the environmental deviation coefficient of the impedance scanning test. For example, the temperature deviation value is obtained based on the temperature and the set temperature standard value, and the humidity and the set The humidity standard value is obtained to obtain the humidity deviation value. The temperature deviation value is summed with the humidity standard value and then averaged to obtain the environmental deviation coefficient of the impedance scanning test. The impedance amplitude fluctuation coefficient of the grid-connected energy storage system reflects the fluctuation of the impedance amplitude of the energy storage system during the grid-connected process. An impedance analyzer is used to measure the impedance amplitude of the grid-connected energy storage system at multiple times within a preset scanning monitoring period, and then the standard deviation and average value of the impedance amplitude are obtained. The ratio of the standard deviation and the average value of the impedance amplitude is used as the impedance amplitude fluctuation coefficient of the grid-connected energy storage system. The voltage fluctuation coefficient of the grid-connected energy storage system reflects the degree of voltage fluctuation in the grid-connected energy storage system. A voltage sensor can be used to measure the voltage of the grid-connected energy storage system at multiple times within a preset scanning monitoring period, and then the ratio of the standard deviation and the average value of the voltage of the grid-connected energy storage system is obtained as the voltage fluctuation coefficient of the grid-connected energy storage system.

[0084] Based on the impedance scanning test parameter processing of the grid-connected energy storage system, a damping characteristic analysis index value of the grid-connected energy storage system is obtained, and the damping characteristic analysis index value of the grid-connected energy storage system is used to quantify the ability of the grid-connected energy storage system to suppress grid oscillation.

[0085] In this embodiment, the damping characteristic analysis index value of the grid-connected energy storage system can be obtained by the following analysis method, and the specific analysis conditions are as follows:

[0086] ;

[0087] In the formula, Represents the damping characteristic analysis index value of the grid-connected energy storage system, Indicates the actual injection signal amplitude of the impedance sweep test, Indicates the injection signal amplitude of the impedance sweep test, It represents the damping characteristic analysis weight factor corresponding to the set injection signal amplitude, Indicates the environmental deviation coefficient of the impedance scan test, Indicates the damping characteristic analysis weight factor corresponding to the set environmental deviation coefficient, Represents the impedance amplitude fluctuation coefficient of the grid-connected energy storage system, Indicates the damping characteristic analysis weight factor corresponding to the set impedance amplitude fluctuation coefficient, Represents the voltage fluctuation coefficient of the grid-connected energy storage system, It represents the damping characteristic analysis weight factor corresponding to the set voltage fluctuation coefficient, and e represents a natural constant.

[0088] It should be added that, in this embodiment, the damping characteristic analysis weight factor corresponding to the preset injection signal amplitude, the damping characteristic analysis weight factor corresponding to the environmental deviation coefficient, the damping characteristic analysis weight factor corresponding to the impedance amplitude fluctuation coefficient and the damping characteristic analysis weight factor corresponding to the voltage fluctuation coefficient are obtained from the impedance scanning test database.

[0089] It should be explained that the damping characteristic analysis weight factors corresponding to the injection signal amplitude, environmental deviation coefficient, impedance amplitude fluctuation coefficient and voltage fluctuation coefficient are respectively used to adjust the importance of the actual injection signal amplitude of the impedance scanning test, the environmental deviation coefficient of the impedance scanning test, the impedance amplitude fluctuation coefficient of the grid-connected energy storage system and the voltage fluctuation coefficient of the grid-connected energy storage system in the process of analyzing the damping characteristic analysis index value of the grid-connected energy storage system. For example, there is a pre-set mapping relationship between the impedance scanning test parameters of the grid-connected energy storage system and the corresponding damping characteristic analysis weight factors in the impedance scanning test database. The real-time damping characteristic analysis weight factors corresponding to the impedance scanning test parameters of the grid-connected energy storage system can be matched through the pre-set mapping relationship. The actual injection signal amplitude of the impedance scanning test, the environmental deviation coefficient of the impedance scanning test, the impedance amplitude fluctuation coefficient of the grid-connected energy storage system and the voltage fluctuation coefficient of the grid-connected energy storage system are matched with the pre-set mapping relationship respectively to obtain the damping characteristic analysis weight factors corresponding to the injection signal amplitude, the environmental deviation coefficient, the impedance amplitude fluctuation coefficient and the voltage fluctuation coefficient.

[0090] In this implementation scheme, the actual injection signal amplitude of the impedance scanning test, the environmental deviation coefficient of the impedance scanning test, the impedance amplitude fluctuation coefficient of the grid-connected energy storage system and the voltage fluctuation coefficient of the grid-connected energy storage system are correlated and do not exist independently. For example, since changes in amplitude may cause measurement errors, the actual injection signal amplitude will affect the impedance value obtained during the test. The environmental deviation coefficient may cause voltage fluctuations in the grid-connected energy storage system, thereby affecting the voltage fluctuation coefficient of the grid-connected energy storage system. Changes in environmental factors may cause fluctuations in the impedance amplitude of the grid-connected energy storage system, thereby affecting the voltage fluctuation of the energy storage system. Comprehensive analysis to obtain the damping characteristic analysis index value of the grid-connected energy storage system can more accurately evaluate the stability of the system under different conditions and provide data support for the design optimization of the grid-connected energy storage system.

[0091] Specifically, the damping characteristic information of the grid-connected energy storage system is obtained, and the specific process is: importing the damping characteristic analysis index value of the grid-connected energy storage system into the damping characteristic analysis model to obtain the damping characteristic information of the grid-connected energy storage system.

[0092] It should be noted that the mathematical formula of the damping characteristic analysis model is:

[0093] ;

[0094] In the formula, Indicates the damping characteristics of the grid-connected energy storage system. Indicates that the damping characteristics are normal. Indicates that the damping characteristics are abnormal. Indicates a damping characteristic failure. Represents the damping characteristic analysis index value of the grid-connected energy storage system, represents the first threshold of damping characteristic analysis, Indicates the second threshold for damping characteristic analysis.

[0095] The damping characteristic analysis index value of the grid-connected energy storage system is marked as .

[0096] The damping characteristic analysis first threshold and the damping characteristic analysis second threshold in the statistical damping characteristic analysis model are respectively marked as , .

[0097] After the damping characteristic analysis model is processed, if , the damping characteristic information of the grid-connected energy storage system is marked as normal damping characteristics.

[0098] like , the damping characteristic information of the grid-connected energy storage system is marked as abnormal damping characteristics.

[0099] like , the damping characteristic information of the grid-connected energy storage system is marked as a damping characteristic fault.

[0100] Specifically, the power stability control of the grid-connected energy storage system is carried out, and the specific process is: extracting the damping characteristic information of the grid-connected energy storage system; if the damping characteristic information of the grid-connected energy storage system indicates that the damping characteristic is normal, then continuing to carry out power stability control with the current operation mode of the grid-connected energy storage system; if the damping characteristic information of the grid-connected energy storage system indicates that the damping characteristic is abnormal, then adjusting the current operation mode of the grid-connected energy storage system to the frequency regulation mode; if the damping characteristic information of the grid-connected energy storage system indicates that the damping characteristic is faulty, then adjusting the current operation mode of the grid-connected energy storage system to the frequency and voltage regulation mode.

[0101] It needs to be explained that the frequency modulation mode controls the frequency of the power grid within a preset frequency range, which can maintain the frequency stability of the grid-connected energy storage system and ensure the reliable operation of the power system. The frequency and voltage modulation mode controls the frequency and voltage of the power grid within a preset range at the same time, which can ensure the dual stability of the power system. When the damping characteristic information is an abnormal damping characteristic, it indicates that the damping capacity of the system has decreased and may not be able to effectively suppress the frequency fluctuations of the power grid. Adjusting the operation mode to the frequency modulation mode can focus on improving the frequency response capability of the system, and compensate for the frequency fluctuations by adjusting the active power, thereby improving the damping effect of the system and ensuring the stability of the power grid frequency. When the damping characteristic information is a damping characteristic failure, it means that the damping capacity of the system is seriously insufficient, and it is impossible to effectively suppress frequency fluctuations or ensure voltage stability. It is necessary to adjust the active and reactive power at the same time to cope with the compound fluctuations of the power grid, thereby more effectively coping with the frequency and voltage fluctuations of the power grid and ensuring the stable operation of the power grid.

[0102] It should be noted that the impedance scanning test method for the energy storage system based on the grid-connected characteristics also includes an impedance scanning test database for storing the first parameter set, the second parameter set and the third parameter set obtained by analyzing the historical data.

[0103] The first parameter set includes defining the current harmonic distortion order, the grid-connected characteristic correction factor corresponding to the frequency fluctuation coefficient, the grid-connected characteristic correction factor corresponding to the current harmonic distortion order, the grid-connected characteristic correction factor corresponding to the electromagnetic interference coefficient, the grid-connected characteristic correction factor corresponding to the unit charge and discharge efficiency, and the output power adjustment value of the power electronic grid-connected converter corresponding to the grid-connected characteristic value interval of each energy storage system.

[0104] The second parameter set includes the reference current peak value, the fluctuation detection assessment factor corresponding to the voltage fluctuation coefficient, the fluctuation detection assessment factor corresponding to the frequency fluctuation coefficient, the fluctuation detection assessment factor corresponding to the phase shift coefficient, the fluctuation detection assessment factor corresponding to the unit current, the fluctuation detection assessment threshold of the grid-connected energy storage system, the phase-locked loop integral gain supplementary value of the grid-connected energy storage system, and the impedance scanning test execution parameters corresponding to each impedance scanning test control value interval.

[0105] The third parameter set includes the damping characteristic analysis weight factor corresponding to the injection signal amplitude, the damping characteristic analysis weight factor corresponding to the environmental deviation coefficient, the damping characteristic analysis weight factor corresponding to the impedance amplitude fluctuation coefficient and the damping characteristic analysis weight factor corresponding to the voltage fluctuation coefficient.

[0106] The second aspect of the present invention provides an apparatus for an impedance scanning test method for an energy storage system based on grid-connected characteristics, further comprising: a processor, and a memory and a network interface connected to the processor; the network interface is connected to a non-volatile memory in a server; when the processor is running, it retrieves a computer program from the non-volatile memory through the network interface, and runs the computer program through the memory to execute the above-mentioned impedance scanning test method for an energy storage system based on grid-connected characteristics.

[0107] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0108] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well.

Claims

1. An impedance scanning test method for an energy storage system based on grid-connected characteristics, characterized in that: include: The energy storage system is connected to the grid through a power electronic grid-connected converter. By continuously analyzing the connection process, the grid-connected characteristic parameters of the energy storage system are obtained, and then the power electronic grid-connected converter is modulated for grid connection. Perform fluctuation detection on the modulated grid-connected energy storage system, and then analyze and obtain the grid fluctuation result of the grid-connected energy storage system, configure the grid-connected energy storage system according to the grid fluctuation result of the grid-connected energy storage system, and process to obtain the impedance scanning test execution parameters, and send the impedance scanning test start signal at the same time; The central controller receives the impedance scanning test start signal, performs an impedance scanning test on the configured grid-connected energy storage system in combination with the impedance scanning test execution parameters, obtains the damping characteristic information of the grid-connected energy storage system, and sends the damping characteristic information of the grid-connected energy storage system to the central control platform; The central control platform receives the damping characteristic information of the grid-connected energy storage system, performs power stability control on the grid-connected energy storage system, and sends the control results to the mobile terminal for display.

2. The energy storage system impedance scanning test method based on grid-connected characteristics according to claim 1 is characterized in that: The specific process of performing grid-connected modulation on the power electronic grid-connected converter is as follows: The grid-connected characteristic parameters of the energy storage system include the frequency fluctuation coefficient of the power grid within a preset monitoring period, the number of current harmonic distortions of the power grid, the electromagnetic interference coefficient of the energy storage system, and the average charge and discharge efficiency of the energy storage system; Based on the energy storage system grid-connected characteristic parameters, the energy storage system grid-connected characteristic values ​​are obtained, and the energy storage system grid-connected characteristic values ​​are used to quantify the stability of the energy storage system in the process of connecting to the power grid; The output power adjustment value of the power electronic grid-connected converter is obtained by matching the grid-connected characteristic value of the energy storage system, the output power of the current power electronic grid-connected converter is added to the output power adjustment value of the power electronic grid-connected converter to obtain the output power target execution value of the power electronic grid-connected converter, and the power electronic grid-connected converter is grid-connected modulated according to the output power target execution value of the power electronic grid-connected converter.

3. The impedance scanning test method for energy storage system based on grid-connected characteristics according to claim 1 is characterized in that: The specific process of performing fluctuation detection on the modulated grid-connected energy storage system is as follows: Performing fluctuation detection on the modulated grid-connected energy storage system to obtain fluctuation detection data of the grid-connected energy storage system, wherein the fluctuation detection data of the grid-connected energy storage system includes a voltage fluctuation coefficient, a frequency fluctuation coefficient, a phase shift coefficient and a current peak value of the grid-connected energy storage system within a preset fluctuation monitoring period; A comprehensive analysis is performed on the fluctuation detection data of the grid-connected energy storage system to obtain a fluctuation detection evaluation value of the grid-connected energy storage system, and the fluctuation detection evaluation value of the grid-connected energy storage system is used to comprehensively quantify the fluctuation degree of the grid-connected energy storage system.

4. The impedance scanning test method for energy storage system based on grid-connected characteristics according to claim 3 is characterized in that: The analysis obtains the grid fluctuation results of the grid-connected energy storage system. The specific process is as follows: The grid fluctuation results of the grid-connected energy storage system include abnormal grid fluctuation and normal grid fluctuation; The fluctuation detection assessment threshold of the grid-connected energy storage system stored in the impedance scanning test database is extracted, and the fluctuation detection assessment value of the grid-connected energy storage system is compared with the fluctuation detection assessment threshold of the grid-connected energy storage system. If the fluctuation detection assessment value of the grid-connected energy storage system is higher than the fluctuation detection assessment threshold of the grid-connected energy storage system, the grid fluctuation result of the grid-connected energy storage system is marked as abnormal grid fluctuation; otherwise, the grid fluctuation result of the grid-connected energy storage system is marked as normal grid fluctuation.

5. The impedance scanning test method for energy storage system based on grid-connected characteristics according to claim 4 is characterized in that: The specific process of configuring the grid-connected energy storage system according to the grid fluctuation result of the grid-connected energy storage system is as follows: Extract the grid fluctuation result of the grid-connected energy storage system. If the grid fluctuation result of the grid-connected energy storage system is that the grid fluctuation is normal, continue to configure the grid-connected energy storage system with the current phase-locked loop integral gain of the grid-connected energy storage system. If the grid fluctuation result of the grid-connected energy storage system is abnormal grid fluctuation, the current phase-locked loop integral gain of the grid-connected energy storage system is added to the set phase-locked loop integral gain supplement value of the grid-connected energy storage system to obtain the phase-locked loop integral gain target achievement value of the grid-connected energy storage system, and the current phase-locked loop integral gain of the grid-connected energy storage system is increased to the phase-locked loop integral gain target achievement value of the grid-connected energy storage system for configuration.

6. The impedance scanning test method for energy storage system based on grid-connected characteristics according to claim 5 is characterized in that: The processing obtains the impedance scanning test execution parameters and sends the impedance scanning test start signal at the same time. The specific process is as follows: Extracting the grid fluctuation result of the grid-connected energy storage system, if the grid fluctuation result of the grid-connected energy storage system is that the grid fluctuation is normal, setting the impedance scanning test standard parameter as the impedance scanning test execution parameter; If the grid fluctuation result of the grid-connected energy storage system is abnormal grid fluctuation, the difference between the fluctuation detection evaluation value of the grid-connected energy storage system and the fluctuation detection evaluation threshold of the grid-connected energy storage system is recorded as the impedance scanning test control value, and the impedance scanning test execution parameters are obtained according to the impedance scanning test control value matching; The impedance scanning test execution parameters include the scanning frequency of the impedance scanning test, the injection signal amplitude of the impedance scanning test and the sampling frequency of the impedance scanning test.

7. The impedance scanning test method for energy storage system based on grid-connected characteristics according to claim 6 is characterized in that: The impedance scanning test execution parameters are combined to perform an impedance scanning test on the configured grid-connected energy storage system. The specific process is as follows: The central controller adjusts the impedance scanning test parameters of the energy storage system impedance scanning test device to the impedance scanning test execution parameters, and performs an impedance scanning test on the configured grid-connected energy storage system through the energy storage system impedance scanning test device to obtain the impedance scanning test parameters of the grid-connected energy storage system, wherein the impedance scanning test parameters of the grid-connected energy storage system include the actual injection signal amplitude of the impedance scanning test within a preset scanning monitoring period, the environmental deviation coefficient of the impedance scanning test, the impedance amplitude fluctuation coefficient of the grid-connected energy storage system, and the voltage fluctuation coefficient of the grid-connected energy storage system; Based on the impedance scanning test parameter processing of the grid-connected energy storage system, a damping characteristic analysis index value of the grid-connected energy storage system is obtained, and the damping characteristic analysis index value of the grid-connected energy storage system is used to quantify the ability of the grid-connected energy storage system to suppress grid oscillation.

8. The impedance scanning test method for energy storage system based on grid-connected characteristics according to claim 7 is characterized in that: The specific process of obtaining the damping characteristic information of the grid-connected energy storage system is as follows: Importing the damping characteristic analysis index value of the grid-connected energy storage system into the damping characteristic analysis model to obtain the damping characteristic information of the grid-connected energy storage system; The damping characteristic analysis index value of the grid-connected energy storage system is marked as ; The damping characteristic analysis first threshold and the damping characteristic analysis second threshold in the statistical damping characteristic analysis model are respectively marked as , ; After the damping characteristic analysis model is processed, if , then the damping characteristic information of the grid-connected energy storage system is marked as normal damping characteristics; like , then the damping characteristic information of the grid-connected energy storage system is marked as abnormal damping characteristics; like , the damping characteristic information of the grid-connected energy storage system is marked as a damping characteristic fault.

9. The method for impedance scanning test of energy storage system based on grid-connected characteristics according to claim 8, characterized in that: The specific process of performing power stability control on the grid-connected energy storage system is as follows: The damping characteristic information of the grid-connected energy storage system is extracted. If the damping characteristic information of the grid-connected energy storage system indicates that the damping characteristic is normal, the power stability control is continued with the current operation mode of the grid-connected energy storage system. If the damping characteristic information of the grid-connected energy storage system indicates that the damping characteristic is abnormal, the current operation mode of the grid-connected energy storage system is adjusted to the frequency regulation mode. If the damping characteristic information of the grid-connected energy storage system indicates that the damping characteristic is faulty, the current operation mode of the grid-connected energy storage system is adjusted to the frequency and voltage regulation mode.

10. An energy storage system impedance scanning test device based on grid-connected characteristics, characterized in that: It includes: a processor, and a memory and a network interface connected to the processor; the network interface is connected to a non-volatile memory in a server; when the processor is running, it calls a computer program from the non-volatile memory through the network interface, and runs the computer program through the memory to execute the method described in any one of claims 1 to 9.

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