Performance evaluation method of energy storage system

Abstract

The invention discloses a performance evaluation method of an energy storage system, which is applied to an electronic device, and the electronic device is connected with the energy storage system. The energy storage system at least comprises an energy storage converter, a non-homologous signal generation device and a signal switching device. The method comprises the following steps: determining a voltage analog signal output by the non-homologous signal generation device according to a preset performance evaluation type; sending the voltage analog signal to the energy storage converter based on the signal switching equipment; acquiring a response parameter output by the energy storage converter when the energy storage converter receives the voltage analog signal; and evaluating the performance of the energy storage system based on the response parameter and an evaluation strategy corresponding to the performance evaluation type. And the accuracy in the performance evaluation process of the energy storage system is improved.

Description

Technical Field

[0001] The present application relates to the technical field of energy storage devices, and in particular to a performance evaluation method for an energy storage system. Background Art

[0002] In recent years, clean energy power generation technologies, such as wind power generation and photovoltaic power generation, have rapidly emerged and become an important part of electricity production. However, the inherent instability of these renewable energy power generation methods - susceptible to natural conditions such as sunlight and wind speed, resulting in large fluctuations in their output power - poses unprecedented challenges to traditional power grids. In order to smoothly integrate a high proportion of renewable energy while ensuring the safety and reliability of the power grid, relevant standards in the power industry require the configuration of electrochemical energy storage systems on the clean energy power generation side. These energy storage systems play a key role in regulating the balance of power supply and demand, stabilizing the frequency of the power grid, and improving the flexibility of the power system.

[0003] Nevertheless, as the scale of electrochemical energy storage systems continues to expand, from early small-capacity systems to today's 25MW / 100MWh or even larger capacities, the capacity limitations of existing grid-connected test equipment have become increasingly prominent and cannot meet the testing needs of large-capacity energy storage systems.

[0004] At present, the method is to use a homologous fault simulation device to collect real-time data from the user-side voltage transformer, and then output a simulated fault voltage signal through an adjustment device. However, the output signal of this method is often difficult to achieve precise control, especially it is difficult to simulate the response of the energy storage system under extremely low or extremely high voltage, resulting in limited comprehensiveness and accuracy of the test.

[0005] Therefore, how to accurately evaluate the performance of energy storage systems has become an urgent problem to be solved. Under the premise of accurate simulation of various power grid faults, the adaptability and responsiveness of large-capacity energy storage systems in grid-connected operation can be comprehensively evaluated. This method can not only ensure the accuracy of the test results, but also be applied in larger-scale energy storage systems, providing more reliable technical guarantees for the stable operation of the power grid. Summary of the invention

[0006] The embodiment of the present application provides a performance evaluation method for an energy storage system, so as to at least solve the problem of low accuracy of performance evaluation of the energy storage system in the related art.

[0007] According to one embodiment of the embodiments of the present application, a performance evaluation method for an energy storage system is provided, which is applied to an electronic device, wherein the electronic device is connected to an energy storage system; the energy storage system includes at least an energy storage inverter, a non-homologous signal generating device, and a signal switching device, including: determining a voltage simulation signal output by the non-homologous signal generating device according to a preset performance evaluation type; sending the voltage simulation signal to the energy storage inverter based on the signal switching device; obtaining a response parameter output by the energy storage inverter when receiving the voltage simulation signal; and evaluating the performance of the energy storage system based on the response parameter and an evaluation strategy corresponding to the performance evaluation type.

[0008] In an exemplary embodiment, the performance evaluation type includes a first fault voltage test; the determination of the voltage simulation signal output by the non-homologous signal generating device according to a preset performance evaluation type includes: when the performance evaluation type includes a first fault voltage test, determining a low voltage simulation signal output by the non-homologous signal generating device based on the first fault voltage test, wherein a voltage value of the low voltage simulation signal is lower than a first preset proportion of a rated voltage.

[0009] In an exemplary embodiment, the performance evaluation type includes a second fault voltage test; the determination of the voltage simulation signal output by the non-homologous signal generating device according to a preset performance evaluation type includes: when the performance evaluation type includes a second fault voltage test, determining a high voltage simulation signal output by the non-homologous signal generating device based on the second fault voltage test, wherein the voltage value of the high voltage simulation signal is higher than a second preset proportion of the rated voltage.

[0010] In an exemplary embodiment, the performance evaluation type includes a frequency adaptability test; the determining of the voltage simulation signal output by the non-homologous signal generating device according to a preset performance evaluation type includes: when the performance evaluation type includes a frequency adaptability test, determining voltage simulation signals of multiple frequencies output by the non-homologous signal generating device based on the frequency adaptability test.

[0011] In an exemplary embodiment, the response parameters include state parameters of the energy storage inverter; the performance evaluation type includes a frequency adaptability test; the performance of the energy storage system is evaluated based on the response parameters and an evaluation strategy corresponding to the performance evaluation type, including: determining the charge and discharge state of the energy storage inverter based on the state parameters; and evaluating the performance of the energy storage system based on the frequency range of the frequency of the voltage simulation signal and the charge and discharge state of the energy storage inverter.

[0012] In an exemplary embodiment, the response parameters include a first current parameter and a first action time parameter of the energy storage inverter; the performance evaluation type includes a first fault voltage test; the performance of the energy storage system is evaluated based on the response parameters and the evaluation strategy corresponding to the performance evaluation type, including: determining a first reactive current and a first dynamic reactive current increment of the energy storage inverter based on the first current parameter; determining a first action response time of the energy storage inverter based on the first time parameter; comparing the sum of the first reactive current and the first dynamic reactive current increment with the rated current of the energy storage inverter to obtain a first current comparison result; and comparing the first action response time with a set first time threshold to obtain a first time comparison result; based on the first current comparison result and the first time comparison result, the performance of the energy storage system is evaluated.

[0013] In an exemplary embodiment, the response parameter includes a second current parameter and a second action time parameter of the energy storage converter; the performance evaluation type includes a second fault voltage test;

[0014] The performance of the energy storage system is evaluated based on the response parameter and the evaluation strategy corresponding to the performance evaluation type, including: determining the second reactive current and the second dynamic reactive current increment of the energy storage inverter based on the second current parameter; determining the second action response time of the energy storage inverter based on the second time parameter; comparing the sum of the second reactive current and the second dynamic reactive current increment with the rated current of the energy storage inverter to obtain a second current comparison result; and comparing the second action response time with a set second time threshold to obtain a second time comparison result; based on the second current comparison result and the second time comparison result, the performance of the energy storage system is evaluated.

[0015] According to another embodiment of the embodiments of the present application, a performance evaluation device for an energy storage system is also provided, including: a determination module, used to determine the voltage simulation signal output by the non-homologous signal generating device according to a preset performance evaluation type; a sending module, used to send the voltage simulation signal to the energy storage inverter based on the signal switching device; an acquisition module, used to obtain the response parameters output by the energy storage inverter when receiving the voltage simulation signal; an evaluation module, used to evaluate the performance of the energy storage system based on the response parameters and an evaluation strategy corresponding to the performance evaluation type.

[0016] According to another aspect of the embodiments of the present application, a computer-readable storage medium is provided, in which a computer program is stored, wherein the computer program is configured to execute the above method when running.

[0017] According to another aspect of the embodiments of the present application, an electronic device is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the method through the computer program.

[0018] According to another aspect of the embodiments of the present application, a computer program product is provided, including a computer program, and when the computer program is executed by a processor, the steps in any of the above method embodiments are implemented.

[0019] In an embodiment of the present application, on the one hand, the non-homologous signal generating device can output a voltage simulation signal according to a preset performance evaluation type. Since the voltage simulation signal is different from the source of the fault signal in the actual power grid, various faults can be simulated more independently and accurately, avoiding the problem of inaccurate testing caused by the performance limitations of the signal source in the prior art. Then, based on the rated response parameters output by the energy storage inverter when receiving the voltage simulation signal, and the evaluation strategy corresponding to the performance evaluation type, the performance of the energy storage system is evaluated, so that the response capability test of the energy storage inverter is more comprehensive and the results are more reliable. On the other hand, the output end of the non-homologous signal generating device is fully controllable. This controllability ensures that each test can accurately simulate the predetermined fault conditions, thereby improving the consistency and repeatability of the test results. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0021] Figure 1 It is a hardware structure block diagram of a computer terminal of a performance evaluation method of an energy storage system according to an embodiment of the present application;

[0022] Figure 2 is a flow chart of a performance evaluation method for an energy storage system according to an embodiment of the present application;

[0023] Figure 3 is a structural block diagram of an energy storage system according to an embodiment of the present application;

[0024] Figure 4 is a structural block diagram of a terminal block in an embodiment of the present application;

[0025] Figure 5 It is a structural block diagram of a performance evaluation device for an energy storage system according to an embodiment of the present application. DETAILED DESCRIPTION

[0026] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0027] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products, or devices; "plurality" means two or more.

[0028] The method embodiments provided in the embodiments of the present application can be executed in a computer terminal or similar computing device or cloud platform or independent physical server or software platform, wherein the above software platform is run through one or more servers. Taking running on a computer terminal as an example, Figure 1 is a hardware structure block diagram of a performance evaluation method for an energy storage system according to an embodiment of the present application. Figure 1 As shown, the computer terminal may include one or more ( Figure 1 Only one is shown in the figure) processor 102 and a memory 104 for storing data. In an exemplary embodiment, the above-mentioned computer terminal may also include a transmission device 106 for communication functions and an input and output device 108, wherein the processor 102 may include but is not limited to a processing device such as a microprocessor MCU or a programmable logic device FPGA.

[0029] It can be understood by those skilled in the art that Figure 1 The structure shown is only for illustration and does not limit the structure of the above-mentioned computer terminal. Figure 1 More or fewer components as shown, or with Figure 1 Equivalent functions or comparisons shown Figure 1 A different configuration with more features is shown.

[0030] The memory 104 can be used to store computer programs, for example, software programs and modules of application software, such as computer programs corresponding to the methods in the embodiments of the present application. The processor 102 executes various functional applications and data processing by running the computer programs stored in the memory 104, that is, the above-mentioned methods are implemented. The memory 104 may include a high-speed random access memory, and may also include a non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memory. In some examples, the memory 104 may further include a memory remotely arranged relative to the processor 102, and these remote memories may be connected to the computer terminal via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0031] The transmission device 106 is used to receive or send data via a network. The specific example of the above network may include a wireless network provided by a communication provider of a computer terminal. In one example, the transmission device 106 includes a network adapter (Network Interface Controller, referred to as NIC), which can be connected to other network devices through a base station so as to communicate with the Internet. In one example, the transmission device 106 can be a radio frequency (RF) module, which is used to communicate with the Internet wirelessly.

[0032] In this embodiment, a performance evaluation method for an energy storage system is provided, which is applied to the above-mentioned computer device. Figure 2 : is a flow chart of a method for evaluating the performance of an energy storage system according to an embodiment of the present application, the process comprising the following steps:

[0033] Step S202, determining a voltage analog signal output by the non-homologous signal generating device according to a preset performance evaluation type;

[0034] Step S204, sending the voltage simulation signal to the energy storage converter based on the signal switching device;

[0035] Step S206, obtaining a response parameter output by the energy storage converter when receiving the voltage simulation signal;

[0036] Step S208: evaluating the performance of the energy storage system based on the response parameter and an evaluation strategy corresponding to the performance evaluation type.

[0037] In an embodiment of the present application, on the one hand, the non-homologous signal generating device can output a voltage simulation signal according to a preset performance evaluation type. Since the voltage simulation signal is different from the source of the fault signal in the actual power grid, various faults can be simulated more independently and accurately, avoiding the problem of inaccurate testing caused by the performance limitations of the signal source in the prior art. Then, based on the rated response parameters output by the energy storage inverter when receiving the voltage simulation signal, and the evaluation strategy corresponding to the performance evaluation type, the performance of the energy storage system is evaluated, so that the response capability test of the energy storage inverter is more comprehensive and the results are more reliable. On the other hand, the output end of the non-homologous signal generating device is fully controllable. This controllability ensures that each test can accurately simulate the predetermined fault conditions, thereby improving the consistency and repeatability of the test results.

[0038] In an exemplary embodiment, the performance evaluation type includes a first fault voltage test; the determination of the voltage simulation signal output by the non-homologous signal generating device according to a preset performance evaluation type includes: when the performance evaluation type includes a first fault voltage test, determining a low voltage simulation signal output by the non-homologous signal generating device based on the first fault voltage test, wherein a voltage value of the low voltage simulation signal is lower than a first preset proportion of a rated voltage.

[0039] It should be noted that the first fault voltage test refers to the low voltage ride-through test (LVRT). When a voltage drop fault occurs in the power grid, this test is designed to verify whether the energy storage system can maintain grid connection and adjust its output to support the grid voltage until the grid returns to normal.

[0040] It is understandable that after determining that the performance evaluation type is low voltage ride-through, the non-homologous signal generating device will output a low voltage analog signal based on this performance evaluation type. The voltage value of the analog signal is set to be lower than the rated voltage of a first preset ratio, and the first preset ratio is usually determined according to relevant industry specifications. For example, the setting of the low voltage analog signal can be less than 90% of the rated voltage, or even lower to 20%-30% of the rated voltage value.

[0041] The low-voltage analog signal generated by the non-homologous signal generating device is transferred to the input end of the energy storage inverter through the signal transfer device. This step ensures that the analog signal can be accurately identified by the energy storage inverter, thereby triggering the corresponding fault response mechanism.

[0042] In the above embodiment, the low voltage conditions common in power grid faults can be directly simulated without interfering with or relying on the signals of the actual power grid. This method allows the energy storage system to be accurately tested under the actual rated conditions, ensuring the accuracy and reliability of the test results. In addition, since the output signal of the non-homologous signal generating device is fully controllable, various voltage drop levels can be simulated, from slight drops to severe drops, making the test more comprehensive and able to cover all voltage abnormal conditions that the energy storage system may encounter.

[0043] In an exemplary embodiment, the performance evaluation type includes a second fault voltage test; the determination of the voltage simulation signal output by the non-homologous signal generating device according to a preset performance evaluation type includes: when the performance evaluation type includes a second fault voltage test, determining a high voltage simulation signal output by the non-homologous signal generating device based on the second fault voltage test, wherein the voltage value of the high voltage simulation signal is higher than a second preset proportion of the rated voltage.

[0044] Among them, the second fault voltage test is the High Voltage Ride-Through (HVRT) test, which aims to verify the response capability and processing mechanism of the energy storage converter when the grid voltage rises abnormally, to ensure that it can operate stably and take appropriate protection measures to avoid system damage.

[0045] It should be noted that the non-homologous signal generating device sets the output to a high voltage analog signal according to the preset second fault voltage test type. The voltage value of the analog signal will be higher than the rated voltage of the second preset ratio, and this preset ratio is also determined according to relevant industry specifications. For example, the voltage value of the high voltage ride-through test can be between 110% and 130% of the rated voltage to test the adaptability of the energy storage system under voltage increase conditions.

[0046] Through the signal switching device, the high voltage analog signal is transmitted from the non-homologous signal generating device to the energy storage inverter, triggering the system's response mechanism to the high voltage fault.

[0047] In the above embodiment, the output signal of the non-homologous signal generating device has high precision and can accurately simulate the abnormal increase of the grid voltage, thereby ensuring the accuracy and credibility of the test process.

[0048] In an exemplary embodiment, the performance evaluation type includes a frequency adaptability test; the determining of the voltage simulation signal output by the non-homologous signal generating device according to a preset performance evaluation type includes: when the performance evaluation type includes a frequency adaptability test, determining voltage simulation signals of multiple frequencies output by the non-homologous signal generating device based on the frequency adaptability test.

[0049] Among them, the frequency adaptability test is a key test to evaluate the responsiveness and continuous operation capability of the energy storage system under grid frequency fluctuations. The stability of grid frequency is the basis for the normal operation of the power system.

[0050] When the performance evaluation type is determined to be a frequency adaptability test, the focus of the test will shift to evaluating the response behavior of the energy storage system under different frequency fluctuations. The non-homologous signal generating device will output a series of voltage simulation signals of preset frequencies according to the requirements of the frequency adaptability test. These frequencies may cover various situations below the rated frequency (such as below 46.5Hz), fluctuating around the rated frequency (such as between 46.5Hz and 51.5Hz), and above the rated frequency (such as above 51.5Hz). In this way, the fluctuations of the grid frequency in different ranges can be simulated to test the operating characteristics of the energy storage system under various frequency anomalies.

[0051] In the above embodiment, the non-homologous signal generating device can simulate accurate frequency fluctuations, including various situations below, equal to, and above the rated frequency, which helps to comprehensively evaluate the frequency adaptability of the energy storage system. Due to the use of non-homologous devices, the test is no longer limited to the frequency range of the actual power grid, and the frequency fluctuation scenario can be freely set, making the test more flexible and able to cover a wider range of frequency abnormalities.

[0052] In an exemplary embodiment, the response parameters include state parameters of the energy storage inverter; the performance evaluation type includes a frequency adaptability test; the performance of the energy storage system is evaluated based on the response parameters and an evaluation strategy corresponding to the performance evaluation type, including: determining the charge and discharge state of the energy storage inverter based on the state parameters; and evaluating the performance of the energy storage system based on the frequency range of the frequency of the voltage simulation signal and the charge and discharge state of the energy storage inverter.

[0053] It should be noted that in the frequency adaptability test, the voltage signal simulated by the non-homologous signal generating device not only contains voltage information, but also contains the characteristics of frequency fluctuation. By comparing the changes in the state parameters of the energy storage converter before and after receiving the frequency fluctuation simulation signal, the response capability of the energy storage system to frequency anomalies can be evaluated.

[0054] Among them, the response parameters may include the state parameters of the energy storage inverter, such as the charging and discharging state, output power (active power P and reactive power Q), and the response time of the energy storage system (the time from detecting the frequency anomaly to taking corresponding actions) and adjustment time (the time required for the system to enter a stable state from the start of response).

[0055] During the test, the real-time operating data of the energy storage converter can be monitored to determine its charging and discharging status. For example, if the detected active power P value is positive and quickly changes from positive to negative after receiving the low-frequency signal, this indicates that the energy storage system changes from the charging state to the discharging state in response to the frequency drop. Conversely, if the energy storage system quickly recovers from the discharging state to the charging state after receiving the high-frequency analog signal, it indicates that it has good adaptability to the frequency increase.

[0056] Frequency adaptability testing usually divides the frequency range into different intervals, such as below 46.5Hz, between 46.5Hz and 51.5Hz, and above 51.5Hz, to simulate various frequency anomalies that may occur in the power system.

[0057] When the frequency is lower than 46.5Hz, if the energy storage system is in a charging state, it is determined that the energy storage system does not meet the requirements; when the fault voltage frequency is between 46.5Hz and 48.5Hz, if the energy storage system in a charging state fails to switch to a discharging state within 0.2s, it is determined that the energy storage system does not meet the requirements; when the fault voltage frequency is between 50.5Hz and 51.5Hz, if the energy storage system in a discharging state fails to switch to a charging state within 0.2s, it is determined that the energy storage system does not meet the requirements; when the fault voltage frequency is higher than 51.5Hz, if the energy storage system is in a discharging state, it is determined that the energy storage system does not meet the requirements; when the fault voltage frequency is between 48.5Hz and 50.5Hz, under the frequency adaptability test, if the energy storage system fails to maintain normal charging and discharging operation, it is determined that the energy storage system does not meet the requirements.

[0058] In the above embodiment, the above evaluation strategy can be used to comprehensively check the response capability of the energy storage system under low frequency, high frequency and frequency fluctuations near the rated frequency, ensuring that it can operate stably under various frequency abnormal conditions.

[0059] In an exemplary embodiment, the response parameters include a first current parameter and a first action time parameter of the energy storage inverter; the performance evaluation type includes a first fault voltage test; the performance of the energy storage system is evaluated based on the response parameters and the evaluation strategy corresponding to the performance evaluation type, including: determining a first reactive current and a first dynamic reactive current increment of the energy storage inverter based on the first current parameter; determining a first action response time of the energy storage inverter based on the first time parameter; comparing the sum of the first reactive current and the first dynamic reactive current increment with the rated current of the energy storage inverter to obtain a first current comparison result; and comparing the first action response time with a set first time threshold to obtain a first time comparison result; based on the first current comparison result and the first time comparison result, the performance of the energy storage system is evaluated.

[0060] Among them, the first current parameter refers to the actual current parameter output by the energy storage converter when the energy storage system receives the simulated low voltage signal, mainly including the first reactive current (that is, the reactive current output by the converter to support the grid voltage when the voltage drops) and the first dynamic reactive current increment (that is, the additional reactive current increment output by the energy storage converter at the moment of voltage drop, which is used to quickly respond to the voltage drop and support the grid voltage).

[0061] The first action time parameter refers to the time from when the energy storage system detects a voltage drop to when it starts to output the first dynamic reactive current increment, i.e. the first action response time. This time parameter directly reflects the system's reaction speed to the voltage drop.

[0062] The sum of the first reactive current and the first dynamic reactive current increment is compared with the rated current of the energy storage converter. If during the voltage drop, this sum is lower than 1.05 times the rated current of the energy storage converter, it means that the maximum output capacity of reactive current under the fault voltage meets the requirements; otherwise, it means that the reactive current output capacity of the system is insufficient and needs to be optimized.

[0063] The first action response time is compared with the set first time threshold (such as the response time specified in the relevant standards, usually not exceeding 30ms). If the first action response time is within the first time threshold, it means that it can respond to the voltage drop in time; if the response time is too long, it means that the system response speed does not meet the requirements, which may affect the stability of the power grid.

[0064] In the above embodiment, by quantitatively analyzing the first reactive current, the first dynamic reactive current increment and the first action response time, the low voltage ride-through capability of the energy storage system can be accurately evaluated to ensure that its response capability during voltage drop meets the requirements for safe and stable operation of the power grid.

[0065] In an exemplary embodiment, the response parameters include a second current parameter and a second action time parameter of the energy storage inverter; the performance evaluation type includes a second fault voltage test; the performance of the energy storage system is evaluated based on the response parameters and the evaluation strategy corresponding to the performance evaluation type, including: determining the second reactive current and the second dynamic reactive current increment of the energy storage inverter based on the second current parameter; determining the second action response time of the energy storage inverter based on the second time parameter; comparing the sum of the second reactive current and the second dynamic reactive current increment with the rated current of the energy storage inverter to obtain a second current comparison result; and comparing the second action response time with a set second time threshold to obtain a second time comparison result; based on the second current comparison result and the second time comparison result, the performance of the energy storage system is evaluated.

[0066] The second current parameter includes the second reactive current and the second dynamic reactive current increment output by the energy storage converter. The second time parameter is the time from when the non-homologous signal generating device outputs a high voltage analog signal, the energy storage system detects a voltage anomaly, to when the converter starts to adjust the output (i.e., the second dynamic reactive current increment takes effect), i.e., the second action response time.

[0067] When the positive sequence component of the fault voltage is between 110% and 130% of the rated voltage, whether the dynamic reactive current increment of the energy storage converter meets the requirements of a specific proportional coefficient. The sum of the second reactive current and the second dynamic reactive current increment is compared with the rated current of the energy storage converter to obtain a second current comparison result. If this sum is lower than 1.05 times the rated current during the voltage rise period, it means that the reactive current output capacity of the energy storage system is insufficient and needs to be optimized. Compare the second action response time with the set second time threshold to obtain a second time comparison result. If the response time exceeds the threshold, such as greater than 30ms, it indicates that the energy storage system responds slowly, which may affect the rapid recovery of the grid voltage.

[0068] Through comprehensive analysis of the second current comparison results and the second time comparison results, the performance of the energy storage system in the high voltage ride-through test can be comprehensively evaluated. If the energy storage system can quickly adjust the output when the voltage rises, the output reactive current increment meets the requirements, and the response time is within the specified threshold, then the system's performance in the high voltage ride-through test is qualified, indicating that it can maintain stable operation of the system when the grid voltage rises abnormally. Conversely, if the system performs poorly in either reactive current output capacity or response time, it means that the system needs to be adjusted or optimized to ensure that it can operate stably in the actual grid and support rapid voltage recovery.

[0069] In order to better understand the process of the performance evaluation method of the above energy storage system, the performance evaluation method of the above energy storage system is described below in combination with an optional embodiment, but it is not used to limit the technical solution of the embodiment of the present application.

[0070] The energy storage system provided in this application adopts a non-homologous simulated fault signal generator, that is, a non-homologous signal generating device, which directly outputs the required voltage (amplitude, frequency) as the instruction for the energy storage system to respond. First, the energy storage system can be operated under rated conditions to carry out grid-connected test projects. Secondly, the output end of the fault simulation generating device is fully controllable, and the output is accurate, which can achieve the expected test effect.

[0071] The present application specifically relates to a method for conducting grid-connected testing on the secondary side of a direct-mounted large-capacity energy storage system. The present application aims to solve the problem of grid-connected testing on the secondary side of a direct-mounted large-capacity energy storage system, so as to overcome the problems of capacity limitation and insufficient test accuracy of existing test devices. The technical solution is as follows:

[0072] refer to Figure 3 As shown, it is a schematic diagram of the structure of the energy storage system, which mainly includes: A1-AN, B1-BN, C1-CN are different power units, which constitute the energy storage converter, as well as voltage transformers PT1, CT, voltage transformer PT2, PCS controller, sampling filter board, terminal block, recorder and simulated fault signal generator. Specifically, PT1 is the voltage transformer on the high-voltage bus side, which collects the three-phase voltages Ua1, Ub1 and Uc1 on the bus side; CT is the current transformer on the energy storage side, which collects the three-phase currents Ia, Ib and Ic on the energy storage side; PT2 is the voltage transformer for energy storage measurement, which collects the three-phase voltages Ua2, Ub2 and Uc2 on the energy storage side; L is the grid-connected reactor at the output port of the energy storage system; the terminal block is the transfer terminal for the sampling signal, and its internal schematic diagram is shown as follows Figure 4 The sampling filter board is used to pre-process the analog signals collected by PT1, PT2, and CT; the PCS controller is used to control the operation mode of the energy storage system under normal and fault conditions; the simulated fault signal generator is driven by 220V AC mains to provide simulated fault voltages Ua1', Ub1', and Uc1' at the AC output port of the energy storage system; the recorder is used to record the three-phase voltage and current signals at the output port of the energy storage system, as well as the simulated fault signals during the grid-connected test.

[0073] In the case of grid-connected testing, the three-phase voltage signal of PT2 is used to ensure that the energy storage system operates in grid-connected mode; refer to Figure 4 As shown, the sliders of the Ua1, Ub1, and Uc1 signals on the terminal block are moved to disconnect the PT1 signal, and the signals Ua1', Ub1', and Uc1' of the non-homologous analog fault signal generator are respectively connected to the 1', 2', and 3' interfaces of the terminal block, and then connected to the filter board, i.e., the sampling filter board. The controller determines the theoretical action of the energy storage system through these three analog fault signals.

[0074] When conducting low and high voltage fault ride-through tests, the energy storage system's continuous operation capability is tested at multiple voltage values, including:

[0075] The energy storage system receives the fault voltage secondary signal U generated by the non-homologous simulated fault signal generator. a1' , U b1' , U c1The recorder records and calculates the action of the active power P and reactive power Q of the energy storage system and the corresponding action time t; when the recorded P, Q and t meet the operation requirements of the energy storage system under voltage fault, the signal of the fault signal generator is reset to end the test.

[0076] Abnormal fault voltage amplitude conditions include:

[0077] When the positive sequence component of the fault voltage is lower than 90% of the rated voltage, the dynamic reactive current increment of the energy storage converter should satisfy the formula:

[0078] ΔI t =K1×(0.9-U t )×I N (0≤U t ≤0.9)

[0079] Among them, ΔI t U is the dynamic reactive current increment of the energy storage converter output; K1 is the dynamic reactive current proportional coefficient of the energy storage converter output, which is not less than 1.5 and not more than 3; t I is the ratio of the actual voltage at the AC port of the energy storage converter to the rated voltage; N is the rated output current value of the AC port of the energy storage converter;

[0080] During the AC port voltage drop, the output reactive current I0 and the dynamic reactive current increment ΔI during normal operation before the voltage drop t When the sum is lower than 1.05 times of the rated current of the energy storage converter, it is determined that the maximum output capacity of reactive current of the energy storage system does not meet the requirements;

[0081] Since the AC port voltage is abnormal (U t ≤0.9), when the response time of the dynamic reactive current of the energy storage converter is greater than 30ms or the adjustment time is greater than 60ms, it is determined that the action time of the energy storage system under voltage fault does not meet the requirements; when the positive sequence component of the fault voltage is between 110% and 130% of the rated voltage, the dynamic reactive current increment of the energy storage converter should meet the formula:

[0082] ΔI t =K3×(U t -1.1)×I N (1.1≤U t ≤1.3)

[0083] Among them, K3 is the proportional coefficient of the dynamic reactive current output by the energy storage converter, which is not less than 1.5;

[0084] During the period when the AC port voltage increases, the output reactive current I0 and the dynamic reactive current increment ΔI during normal operation before the voltage increases tWhen the difference is less than 1.05 times of the rated current of the energy storage converter, it is determined that the maximum output capacity of reactive current of the energy storage system does not meet the requirements;

[0085] Since the AC port voltage is abnormal (U t ≥1.1) When the response time of the dynamic reactive current of the energy storage converter is greater than 30ms or the adjustment time is greater than 60ms, it is determined that the action time of the energy storage system under voltage fault does not meet the requirements;

[0086] Fault voltage frequency abnormalities include:

[0087] When the fault voltage frequency is lower than 46.5 Hz, if the energy storage system is in a charging state, it is determined that the energy storage system does not meet the requirements;

[0088] When the fault voltage frequency is between 46.5Hz and 48.5Hz, if the energy storage system in the charging state fails to switch to the discharging state within 0.2s, it is determined that the energy storage system does not meet the requirements;

[0089] When the fault voltage frequency is between 50.5Hz and 51.5Hz, if the energy storage system in the discharging state fails to switch to the charging state within 0.2s, it is determined that the energy storage system does not meet the requirements;

[0090] When the fault voltage frequency is higher than 51.5 Hz, if the energy storage system is in a discharging state, it is determined that the energy storage system does not meet the requirements;

[0091] When the fault voltage frequency is between 48.5Hz and 50.5Hz, under the frequency adaptability test, if the energy storage system fails to maintain normal charging and discharging operation, it is determined that the energy storage system does not meet the requirements;

[0092] When the fault voltage frequency is between 48.5Hz and 50.5Hz, under the inertia response test, the energy storage system provides inertia response under the condition that the formula is satisfied, and the active power control satisfies the formula:

[0093]

[0094] Wherein, Δf is the deviation between the AC port frequency of the energy storage system and the rated frequency of the system, f is the frequency detected by the AC port of the energy storage system, ΔP is the change in active power of the energy storage system, T j is the inertia time constant (4-14s), f n is the system rated frequency, P n is the system rated power;

[0095] When participating in inertia response control, if the response time of the energy storage system is greater than 100ms and the adjustment time is greater than 300ms, it is determined that the energy storage system does not meet the requirements.

[0096] The present application provides a method for performing grid adaptability, inertia response and fault voltage ride-through tests on the secondary side of power electronic equipment. By serially inserting a simulated fault signal generator into the voltage sampling point of the energy storage system, the ability of the energy storage system to continuously operate under different working conditions of the electrochemical energy storage system required by the national standard is tested to ensure the safe and stable operation of the power system under high-penetration new energy.

[0097] The present application achieves precise testing under rated conditions of the energy storage system by simulating grid faults on the secondary side, thereby improving the accuracy and practicality of the test; at the same time, the method is not limited by the capacity of existing test equipment and can adapt to the testing of energy storage systems with larger capacities, thus expanding the scope of application and creating conditions for the widespread application of energy storage technology and the expansion of the market scale; in addition, the use of non-homologous simulated fault signal generators ensures the precise controllability of the output signal and achieves the expected test effect; the present invention also provides comprehensive testing capabilities to ensure the safe and stable operation of the energy storage system in a high-penetration new energy power system; finally, the present application simplifies the test process, improves test efficiency and accuracy, reduces the comprehensive cost of grid-connected testing of energy storage systems, and promotes the improvement of the return on investment and sustainable development of new energy power systems.

[0098] Through the description of the above implementation methods, those skilled in the art can clearly understand that the method according to the above embodiment can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present application, or the part that contributes to the prior art, can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk), and includes a number of instructions for a terminal device (which can be a mobile phone, computer, server, or network device, etc.) to execute the methods of each embodiment of the present application.

[0099] The present application also provides a structural block diagram of a performance evaluation device for an energy storage system. Figure 5 is a structural block diagram of a performance evaluation device for an energy storage system according to an embodiment of the present application; Figure 5 As shown, including:

[0100] A determination module 52, configured to determine a voltage analog signal output by the non-homologous signal generating device according to a preset performance evaluation type;

[0101] A sending module 54, configured to send the voltage simulation signal to the energy storage converter based on the signal switching device;

[0102] An acquisition module 56, used to acquire a response parameter output by the energy storage converter when receiving the voltage simulation signal;

[0103] The evaluation module 58 is used to evaluate the performance of the energy storage system based on the response parameter and an evaluation strategy corresponding to the performance evaluation type.

[0104] Through the above-mentioned device, on the one hand, the non-homologous signal generating device can output a voltage simulation signal according to a preset performance evaluation type. Since the voltage simulation signal is different from the source of the fault signal in the actual power grid, various faults can be simulated more independently and accurately, avoiding the problem of inaccurate testing caused by the performance limitation of the signal source in the prior art. Then, based on the rated response parameters output by the energy storage inverter when receiving the voltage simulation signal, and the evaluation strategy corresponding to the performance evaluation type, the performance of the energy storage system is evaluated, so that the response capability test of the energy storage inverter is more comprehensive and the results are more reliable. On the other hand, the output end of the non-homologous signal generating device is fully controllable. This controllability ensures that each test can accurately simulate the predetermined fault conditions, thereby improving the consistency and repeatability of the test results.

[0105] In an exemplary embodiment, the performance evaluation type includes a first fault voltage test; the determination module 52 is also used to determine, when the performance evaluation type includes a first fault voltage test, a low voltage analog signal output by the non-homologous signal generating device based on the first fault voltage test, wherein the voltage value of the low voltage analog signal is lower than a first preset proportion of the rated voltage.

[0106] In an exemplary embodiment, the performance evaluation type includes a second fault voltage test; the determination module 52 is also used to determine the high voltage analog signal output by the non-homologous signal generating device based on the second fault voltage test when the performance evaluation type includes the second fault voltage test, wherein the voltage value of the high voltage analog signal is higher than the rated voltage of a second preset proportion.

[0107] In an exemplary embodiment, the performance evaluation type includes a frequency adaptability test; the determination module 52 is further used to determine the voltage simulation signals of multiple frequencies output by the non-homologous signal generating device based on the frequency adaptability test when the performance evaluation type includes the frequency adaptability test.

[0108] In an exemplary embodiment, the response parameters include state parameters of the energy storage inverter; the performance evaluation type includes a frequency adaptability test; the evaluation module 58 is further used to determine the charge and discharge state of the energy storage inverter based on the state parameters; and to evaluate the performance of the energy storage system based on the frequency range of the frequency of the voltage simulation signal and the charge and discharge state of the energy storage inverter.

[0109] In an exemplary embodiment, the response parameters include a first current parameter and a first action time parameter of the energy storage inverter; the performance evaluation type includes a first fault voltage test; the evaluation module 58 is also used to determine the first reactive current and the first dynamic reactive current increment of the energy storage inverter based on the first current parameter; determine the first action response time of the energy storage inverter based on the first time parameter; compare the sum of the first reactive current and the first dynamic reactive current increment with the rated current of the energy storage inverter to obtain a first current comparison result; and compare the first action response time with a set first time threshold to obtain a first time comparison result; based on the first current comparison result and the first time comparison result, evaluate the performance of the energy storage system.

[0110] In an exemplary embodiment, the response parameters include a second current parameter and a second action time parameter of the energy storage inverter; the performance evaluation type includes a second fault voltage test; the evaluation module 58 is also used to determine the second reactive current and the second dynamic reactive current increment of the energy storage inverter based on the second current parameter; determine the second action response time of the energy storage inverter based on the second time parameter; compare the sum of the second reactive current and the second dynamic reactive current increment with the rated current of the energy storage inverter to obtain a second current comparison result; and compare the second action response time with a set second time threshold to obtain a second time comparison result; based on the second current comparison result and the second time comparison result, evaluate the performance of the energy storage system.

[0111] An embodiment of the present application further provides a storage medium, which includes a stored program, wherein the program executes any of the above methods when it is run.

[0112] Optionally, in this embodiment, the storage medium may be configured to store program codes for executing the following steps:

[0113] S1, determining a voltage analog signal output by the non-homologous signal generating device according to a preset performance evaluation type;

[0114] S2, sending the voltage simulation signal to the energy storage converter based on the signal switching device;

[0115] S3, obtaining a response parameter output by the energy storage converter when receiving the voltage simulation signal;

[0116] S4: Evaluate the performance of the energy storage system based on the response parameter and an evaluation strategy corresponding to the performance evaluation type.

[0117] An embodiment of the present application further provides an electronic device, including a memory and a processor, wherein a computer program is stored in the memory, and the processor is configured to run the computer program to execute the steps in any one of the above method embodiments.

[0118] Optionally, the electronic device may further include a transmission device and an input / output device, wherein the transmission device is connected to the processor, and the input / output device is connected to the processor.

[0119] Optionally, in this embodiment, the processor may be configured to perform the following steps through a computer program:

[0120] S1, determining a voltage analog signal output by the non-homologous signal generating device according to a preset performance evaluation type;

[0121] S2, sending the voltage simulation signal to the energy storage converter based on the signal switching device;

[0122] S3, obtaining a response parameter output by the energy storage converter when receiving the voltage simulation signal;

[0123] S4: Evaluate the performance of the energy storage system based on the response parameter and an evaluation strategy corresponding to the performance evaluation type.

[0124] Optionally, in this embodiment, the above-mentioned storage medium may include but is not limited to: a USB flash drive, a read-only memory (ROM), a random access memory (RAM), a mobile hard disk, a magnetic disk or an optical disk, and other media that can store program codes.

[0125] An embodiment of the present application further provides a computer program product, which includes a computer program. When the computer program is executed by a processor, the steps in any one of the above method embodiments are implemented.

[0126] An embodiment of the present application further provides another computer program product, including a non-volatile computer-readable storage medium, wherein the non-volatile computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps in any of the above method embodiments are implemented.

[0127] An embodiment of the present application also provides a computer program, which includes computer instructions stored in a computer-readable storage medium; a processor of a computer device reads the computer instructions from the computer-readable storage medium, and the processor executes the computer instructions, so that the computer device performs the steps in any one of the above method embodiments.

[0128] Optionally, the specific examples in this embodiment may refer to the examples described in the above embodiments and optional implementation modes, and this embodiment will not be described in detail here.

[0129] Obviously, those skilled in the art should understand that the above modules or steps of the present application can be implemented by a general computing device, they can be concentrated on a single computing device, or distributed on a network composed of multiple computing devices, and optionally, they can be implemented by a program code executable by a computing device, so that they can be stored in a storage device and executed by the computing device, and in some cases, the steps shown or described can be executed in a different order from that herein, or they can be made into individual integrated circuit modules, or multiple modules or steps therein can be made into a single integrated circuit module for implementation. Thus, the present application is not limited to any specific combination of hardware and software.

[0130] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the principles of the present application shall be included in the protection scope of the present application.

Claims

1. A performance evaluation method for an energy storage system, applied to an electronic device, wherein the electronic device is connected to the energy storage system; the energy storage system at least includes an energy storage converter, a non-homologous signal generating device, and a signal switching device, characterized in that: include: Determining a voltage analog signal output by the non-homologous signal generating device according to a preset performance evaluation type; Sending the voltage simulation signal to the energy storage converter based on the signal switching device; Acquiring a response parameter output by the energy storage converter when receiving the voltage simulation signal; The performance of the energy storage system is evaluated based on the response parameter and an evaluation strategy corresponding to the performance evaluation type.

2. The method according to claim 1, characterized in that The performance evaluation type includes a first fault voltage test; The step of determining the voltage simulation signal output by the non-homologous signal generating device according to a preset performance evaluation type includes: In the case where the performance evaluation type includes a first fault voltage test, a low voltage analog signal output by the non-homologous signal generating device based on the first fault voltage test is determined, wherein a voltage value of the low voltage analog signal is lower than a first preset proportion of a rated voltage.

3. The method according to claim 1, characterized in that: The performance evaluation type includes a second fault voltage test; The step of determining the voltage simulation signal output by the non-homologous signal generating device according to a preset performance evaluation type includes: In the case where the performance evaluation type includes a second fault voltage test, a high voltage analog signal output by the non-homologous signal generating device based on the second fault voltage test is determined, wherein a voltage value of the high voltage analog signal is higher than a second preset proportion of a rated voltage.

4. The method according to claim 1, characterized in that The types of performance evaluation include frequency adaptability testing; The step of determining the voltage simulation signal output by the non-homologous signal generating device according to a preset performance evaluation type includes: In the case where the performance evaluation type includes a frequency adaptability test, voltage analog signals of multiple frequencies output by the non-homologous signal generating device based on the frequency adaptability test are determined.

5. The method according to claim 1, characterized in that: The response parameter includes the state parameter of the energy storage converter; the performance evaluation type includes a frequency adaptability test; The step of evaluating the performance of the energy storage system based on the response parameter and an evaluation strategy corresponding to the performance evaluation type includes: Based on the state parameter, determining the charge and discharge state of the energy storage converter; The performance of the energy storage system is evaluated based on the frequency interval of the voltage simulation signal and the charge and discharge state of the energy storage converter.

6. The method according to claim 1, characterized in that The response parameter includes a first current parameter and a first action time parameter of the energy storage converter; the performance evaluation type includes a first fault voltage test; The step of evaluating the performance of the energy storage system based on the response parameter and an evaluation strategy corresponding to the performance evaluation type includes: Based on the first current parameter, determining a first reactive current and a first dynamic reactive current increment of the energy storage converter; Based on the first time parameter, determining a first action response time of the energy storage converter; Compare the sum of the first reactive current and the first dynamic reactive current increment with the rated current of the energy storage converter to obtain a first current comparison result; and compare the first action response time with a set first time threshold to obtain a first time comparison result; The performance of the energy storage system is evaluated based on the first current comparison result and the first time comparison result.

7. The method according to claim 1, characterized in that The response parameter includes a second current parameter and a second action time parameter of the energy storage converter; the performance evaluation type includes a second fault voltage test; The step of evaluating the performance of the energy storage system based on the response parameter and an evaluation strategy corresponding to the performance evaluation type includes: Based on the second current parameter, determining a second reactive current and a second dynamic reactive current increment of the energy storage converter; Based on the second time parameter, determining a second action response time of the energy storage converter; Compare the sum of the second reactive current and the second dynamic reactive current increment with the rated current of the energy storage converter to obtain a second current comparison result; and compare the second action response time with a set second time threshold to obtain a second time comparison result; Based on the second current comparison result and the second time comparison result, the performance of the energy storage system is evaluated.

8. A performance evaluation device for an energy storage system, characterized in that: include: A determination module, used to determine the voltage analog signal output by the non-homologous signal generating device according to a preset performance evaluation type; A sending module, used for sending the voltage simulation signal to the energy storage converter based on the signal switching device; An acquisition module, used for acquiring a response parameter output by the energy storage converter when receiving the voltage simulation signal; An evaluation module is used to evaluate the performance of the energy storage system based on the response parameter and an evaluation strategy corresponding to the performance evaluation type.

9. A computer-readable storage medium, characterized in that: The computer-readable storage medium includes a stored program, wherein the program executes the method described in any one of claims 1 to 7 when executed.

10. An electronic device comprising a memory and a processor, characterized in that: A computer program is stored in the memory, and the processor is configured to execute the method according to any one of claims 1 to 7 through the computer program.

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