Checking method and system for stability of network construction type energy storage improving system, storage medium and processor

Abstract

The invention relates to the technical field of power systems, in particular to a checking method and system for stability of a network construction type energy storage improving system, a storage medium and a processor. The method comprises the following steps: checking an electromechanical transient simulation model for constructing the network type energy storage; checking the voltage and frequency support capability of the network-forming energy storage; and checking the capacity of the networking type energy storage. According to the method, the accuracy of the parameters of the network construction type energy storage model and the accuracy of the simulation result of the stability of the power system can be well improved, and the actual requirement of power system planning for simulation is met. According to the method, three scenes are constructed, corresponding simulation is carried out, and whether obvious errors exist in the parameters of the network construction type energy storage model provided by a manufacturer or not can be effectively judged according to whether the simulation result deviation exceeds a threshold value or not, so that the situation that a wrong conclusion is obtained by a subsequent check result is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of power systems, and in particular to a verification method, system, storage medium and processor for improving the stability of a grid-type energy storage system. Background Art

[0002] With the rapid development of new power systems based on new energy, the number of new energy stations is increasing, and the rapid transformation of the energy structure poses a major challenge to the safe operation of the power system.

[0003] Grid-type energy storage uses the energy storage system as a voltage source, which can set voltage parameters internally and output voltage and frequency. Therefore, grid-type energy storage can be operated in both grid-connected and isolated grids, and has strong support for the grid. It can also improve the problems of short-circuit capacity and lack of rotational inertia of new power systems. As a flexible resource adjustment and active support means, grid-type energy storage technology has become one of the keys for new power systems to cope with grid security challenges.

[0004] Evaluation and verification of the effect of grid-connected energy storage on the stability of the power system has an important impact on the planning and construction of grid-connected energy storage. If the grid-connected energy storage simulation model provided by the manufacturer is not accurate enough or the evaluation and verification methods are not perfect enough, it may lead to deviations in the evaluation results, which in turn will cause the grid-connected energy storage to fail to actually meet the needs of improving the stability of the power system after construction and operation. Summary of the invention

[0005] In view of the problems in the prior art, the present invention provides a verification method, system, storage medium and processor for improving the stability of a grid-type energy storage system. The specific technical solutions are as follows:

[0006] A method for verifying the stability of a grid-connected energy storage system includes the following steps:

[0007] Verify the electromechanical transient simulation model of the grid-type energy storage, build multiple operating scenarios and perform corresponding simulations, record the simulation results of several electrical quantity deviations of the grid-type energy storage, and determine whether there are errors in the grid-type energy storage model parameters provided by the manufacturer based on whether the several electrical quantity deviations exceed the corresponding deviation thresholds;

[0008] Verify the voltage support capability of grid-type energy storage, calculate the voltage support capability index of grid-type energy storage, and evaluate the voltage support capability of grid-type energy storage;

[0009] Verify the frequency support capability of grid-type energy storage, calculate the frequency support capability index of grid-type energy storage, and evaluate the frequency support capability of grid-type energy storage;

[0010] Verify the capacity of the grid-type energy storage to determine whether the planned capacity of the grid-type energy storage is appropriate.

[0011] Preferably, the construction of the operating scenario and the corresponding simulation specifically include the following:

[0012] (1) Build a single-machine infinite system of grid-connected energy storage and perform fault-free simulation and line tripping fault simulation;

[0013] (2) Build a single-machine load system with grid-connected energy storage to simulate line tripping faults and load shedding small disturbance faults;

[0014] (3) Build a system that connects grid-connected energy storage to the actual power grid to simulate line tripping faults, DC system bipolar blocking faults, and low voltage ride-through faults.

[0015] Preferably, the simulation results of recording several electrical quantity deviations of the grid-type energy storage are used to determine whether the grid-type energy storage model parameters provided by the manufacturer are wrong according to whether the several electrical quantity deviations exceed the corresponding deviation thresholds. The electrical quantity deviation calculation formula is as follows:

[0016]

[0017] where d i is the ith simulation data of the electrical quantity D, s i is the i-th corresponding reasonable data of the electrical quantity D; the electrical quantity D is the voltage, active power, reactive power and frequency of the grid-type energy storage, and the electrical quantity deviation ΔD includes the voltage deviation, active power deviation, reactive power deviation and frequency deviation of the grid-type energy storage;

[0018] The judgment formula of whether the electrical quantity deviation exceeds the corresponding deviation threshold is: ΔD<δ D , where δ D is the deviation threshold; if all the electrical quantity deviations are less than the corresponding deviation threshold in all operating scenarios, proceed to the next step; if at least one electrical quantity deviation is greater than the corresponding deviation threshold in at least one operating scenario, do not proceed to the next step, first perform model parameter correction by the manufacturer or by itself, and then perform the electromechanical transient simulation model of the grid-type energy storage again, until all the electrical quantity deviations are less than the corresponding deviation threshold in all operating scenarios, and then proceed to the next step.

[0019] Preferably, the checking of the voltage support capability of the grid-type energy storage, calculating the voltage support capability index of the grid-type energy storage, and evaluating the voltage support capability of the grid-type energy storage specifically include the following steps:

[0020] Construct a system for connecting a grid-type energy storage to the planned power grid, and use the shortest path method to search for the shortest path l from the grid-type energy storage node to the i-th new energy station node. i and the shortest electrical distance d i , i=1,2,…,N, where l i is the shortest path from the i-th new energy station to the grid-connected energy storage, d i is the reactance value corresponding to the shortest path, and N is the number of new energy stations whose electrical distance around the grid-type energy storage is less than the given value L;

[0021] The shortest path l from the grid-type energy storage node to the i-th new energy station node i The single-phase instantaneous fault simulation is performed on the ith new energy station node to obtain the voltage difference Δu after and during the fault. i ;

[0022] Replace the grid-connected energy storage with the grid-following energy storage, and repeat the above simulation to obtain the voltage difference between the i-th new energy station node after and during the fault:

[0023] Calculate the voltage support capability index U of grid-connected energy storage s :

[0024]

[0025] U s The larger it is, the stronger the voltage support capability of the grid-type energy storage is.

[0026] Preferably, the checking of the frequency support capability of the grid-forming energy storage, calculating the frequency support capability index of the grid-forming energy storage, and evaluating the frequency support capability of the grid-forming energy storage specifically include the following steps:

[0027] Using the cut set method in graph theory, we search for nodes with electrical distances around them that are less than a given value D. s The key section k j ={a1,a2,…,a m}, j = 1, 2, ..., M, where a m It belongs to the key section k j A circuit, m is a key section k j The number of lines, D s is the maximum allowable value of the electrical distance from the line belonging to the critical section to the grid-forming energy storage node, and M is the number of critical sections around the grid-forming energy storage node;

[0028] For the key section k j Perform line fault tripping simulation, that is, disconnect the critical section k j All lines {a1,a2,…,am}, and obtain the frequency difference Δf of the grid-type energy storage node after the fault j ;

[0029] Calculate the frequency support capability index F of grid-connected energy storage s :

[0030]

[0031] F s The larger the value, the stronger the frequency support capability of the grid-type energy storage.

[0032] Preferably, the checking of the capacity of the grid-type energy storage to determine whether the planned capacity of the grid-type energy storage is appropriate specifically comprises the following steps:

[0033] Increase the rated capacity of the grid-type energy storage, calculate the voltage support capability index of the grid-type energy storage again, repeat the above steps until the voltage support capability index of the grid-type energy storage is greater than the given value, and record the corresponding grid-type energy storage capacity value S Z ;

[0034] Increase the rated capacity of the grid-type energy storage, calculate the frequency support capability index of the grid-type energy storage again, repeat the above steps until the frequency support capability index of the grid-type energy storage is greater than the given value, and record the corresponding grid-type energy storage capacity value S F ;

[0035] The planned capacity of grid-type energy storage S p With capacity value S Z and S F contrast:

[0036] If S p >150%×S Z , and S p >150%×S F , indicating that the planned capacity value of grid-type energy storage is too large;

[0037] If 150%×S Z >S p >90%×S Z , and 150%×S F >S p >90%×S F , indicating that the planned capacity value of grid-type energy storage is appropriate;

[0038] If S p <90%×S z , and S p <90%×S z , indicating that the planned capacity value of grid-type energy storage is relatively small.

[0039] A verification system for improving the stability of a grid-type energy storage system, applied to the method described, comprising:

[0040] The model verification module is used to verify the electromechanical transient simulation model of the grid-type energy storage, construct multiple operating scenarios and perform corresponding simulations, record the simulation results of several electrical quantity deviations of the grid-type energy storage, and determine whether there are errors in the grid-type energy storage model parameters provided by the manufacturer based on whether the several electrical quantity deviations exceed the corresponding deviation thresholds;

[0041] The voltage support capability verification module is used to verify the voltage support capability of the grid-type energy storage, calculate the voltage support capability index of the grid-type energy storage, and evaluate the voltage support capability of the grid-type energy storage;

[0042] The frequency support capability verification module is used to verify the frequency support capability of the grid-type energy storage, calculate the frequency support capability index of the grid-type energy storage, and evaluate the frequency support capability of the grid-type energy storage;

[0043] The capacity verification module verifies the capacity of the grid-type energy storage and determines whether the planned capacity of the grid-type energy storage is appropriate.

[0044] A computer-readable storage medium includes a stored program, wherein when the program is run, the device where the computer-readable storage medium is located is controlled to execute the verification method for improving the stability of the grid-type energy storage system.

[0045] A processor is used to run a program, wherein when the program is running, the method for verifying the stability of a grid-type energy storage system is executed.

[0046] Compared with the prior art, the present invention has the following beneficial effects:

[0047] The method of the present invention comprises the following steps: checking the electromechanical transient simulation model of the grid-type energy storage; checking the voltage and frequency support capability of the grid-type energy storage; and checking the capacity of the grid-type energy storage.

[0048] The present invention can improve the accuracy of the parameters of the grid-connected energy storage model and the accuracy of the simulation results of the power system stability, thus meeting the actual needs of power system planning for simulation.

[0049] Among them, by constructing three scenarios and conducting corresponding simulations, and then judging whether the deviation of the simulation results exceeds the threshold, it is possible to effectively determine whether the parameters of the grid-type energy storage model provided by the manufacturer have obvious errors, so as to avoid incorrect conclusions from subsequent verification results. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for the specific embodiments or the description of the prior art. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn according to the actual scale.

[0051] Figure 1 It is a schematic diagram of the process of the present invention;

[0052] Figure 2 It is a system principle diagram of the present invention. DETAILED DESCRIPTION

[0053] 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 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.

[0054] It should be understood that when used in this specification and the appended claims, the terms "include" and "comprises" indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0055] It should also be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0056] It should be further understood that the term "and / or" used in the present description and the appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0057] Embodiment 1:

[0058] like Figure 1 As shown, this embodiment provides a method for checking the stability of a grid-connected energy storage system, comprising the following steps:

[0059] Step S1, verifying the electromechanical transient simulation model of the grid-type energy storage, constructing multiple operating scenarios and performing corresponding simulations, recording the simulation results of several electrical quantity deviations of the grid-type energy storage, and judging whether the parameters of the grid-type energy storage model provided by the manufacturer are wrong according to whether the several electrical quantity deviations exceed the corresponding deviation thresholds. The grid-type energy storage electromechanical transient simulation model is used to simulate and analyze the transient behavior of the grid-type energy storage in operation.

[0060] The simulation results of several electrical quantity deviations of the grid-type energy storage are recorded. According to whether the several electrical quantity deviations exceed the corresponding deviation thresholds, it is judged whether there are errors in the grid-type energy storage model parameters provided by the manufacturer. The details are as follows:

[0061] The calculation formula of electrical quantity deviation is:

[0062]

[0063] where d i is the ith simulation data of the electrical quantity D, s i It is the i-th corresponding reasonable data of the electrical quantity D; the corresponding reasonable data refers to the data obtained by other means other than simulation that can be used to verify the rationality of the simulation results. The electrical quantity D is the voltage, active power, reactive power, and frequency of the grid-type energy storage. The electrical quantity deviation ΔD includes the voltage deviation, active power deviation, reactive power deviation, and frequency deviation of the grid-type energy storage.

[0064] The judgment formula of whether the electrical quantity deviation exceeds the corresponding deviation threshold is: ΔD<δ D , where δ D is the deviation threshold.

[0065] In this embodiment, constructing a working scenario and performing corresponding simulation specifically includes the following:

[0066] (1) Build a single-machine infinite system with grid-connected energy storage and perform fault-free simulation and line tripping fault simulation.

[0067] The single-machine infinite system means that the grid-type energy storage constitutes a node, the infinite power source constitutes a node, and the two are connected by a circuit. The node voltage of the grid-type energy storage is set to be equal to its rated voltage, and the active power and reactive power are both equal to 0.

[0068] When performing a fault-free simulation, the simulation results of the voltage, active power, reactive power and frequency of the grid-connected energy storage are recorded.

[0069] Model calibration method:

[0070] Calculate the voltage simulation result curve deviation: Among them Ui is the ith simulation data, U e is the rated voltage of the grid-type energy storage, and n is the total number of simulation data. Similarly, the deviations of the simulation results of active power, reactive power and frequency are obtained: ΔP, ΔQ, ΔF.

[0071] If ΔU<δ u , and ΔP<δ p , and ΔQ<δ q , and ΔF<δ f , then the model provided by the manufacturer is judged to be fault-free and the simulation is normal, otherwise it is judged to be abnormal. u is the voltage deviation threshold, δ p is the active power deviation threshold, δ q is the reactive power deviation threshold, δ f is the frequency deviation threshold.

[0072] When simulating a line tripping fault, add a line between the grid-forming energy storage node and the infinite power source node, and then simulate the fault tripping of the line. Record the simulation results of the voltage, active power, reactive power and frequency of the grid-forming energy storage. According to the above model verification method, determine whether the fault simulation of the model provided by the manufacturer is normal.

[0073] (2) Construct a single-machine load system with grid-connected energy storage to simulate line tripping faults and load shedding small disturbance faults.

[0074] The single-machine load system means that the grid-type energy storage constitutes a node, the load constitutes a node, and the two are connected by a circuit. The node voltage of the grid-type energy storage is set to be equal to its rated voltage, and the active power and reactive power are both equal to 0.

[0075] When performing fault simulation, add a line between the grid-forming energy storage node and the infinite power source node, and then perform fault tripping simulation on the line. Record the simulation results of the voltage, active power, reactive power and frequency of the grid-forming energy storage. Use the above model verification method to determine whether the fault simulation of the model provided by the manufacturer is normal.

[0076] When simulating a small disturbance fault with load shedding, part of the load is removed at the load node, and the load shedding amount accounts for 5-30% of the total load. Record the simulation results of the voltage, active power, reactive power and frequency of the grid-type energy storage. According to the above model verification method, determine whether the fault simulation of the model provided by the manufacturer is normal.

[0077] (3) Build a system that connects grid-connected energy storage to the actual power grid to simulate line tripping faults, DC system bipolar blocking faults, and low voltage ride-through faults.

[0078] The actual power grid simulation system refers to: an electromechanical transient simulation system in which the grid-forming energy storage is actually connected to the power grid. The node voltage of the grid-forming energy storage is set equal to its rated voltage, and the active power and reactive power are both equal to 0.

[0079] When performing fault simulation, select a line near the location where the grid-forming energy storage is connected to the power grid, and then perform fault tripping simulation on the line. Record the simulation results of the voltage, active power, reactive power and frequency of the grid-forming energy storage. Use the above model verification method to determine whether the fault simulation of the model provided by the manufacturer is normal.

[0080] When simulating a bipolar blocking fault in a DC system, select a DC near the grid-connected energy storage and perform a bipolar blocking fault simulation in the DC system. Record the simulation results of the voltage, active power, reactive power and frequency of the grid-connected energy storage. Use the above model verification method to determine whether the fault simulation of the model provided by the manufacturer is normal.

[0081] When conducting low voltage ride-through fault simulation, select a new energy plant near the grid-connected energy storage to conduct repeated low voltage ride-through fault simulation. Record the simulation results of the voltage, active power, reactive power and frequency of the grid-connected energy storage. Use the above model verification method to determine whether the fault simulation of the model provided by the manufacturer is normal.

[0082] If all the electrical quantity deviations are less than the corresponding deviation threshold in all operating scenarios, proceed to the next step; if at least one electrical quantity deviation is greater than the corresponding deviation threshold in at least one operating scenario, do not proceed to the next step, first perform model parameter correction by the manufacturer or by itself, and then perform the electromechanical transient simulation model calibration of the grid-type energy storage again, until all the electrical quantity deviations are less than the corresponding deviation threshold in all operating scenarios, and then proceed to the next step.

[0083] By constructing three scenarios and performing corresponding simulations, and then judging whether the deviation of the simulation results exceeds the threshold, it is possible to effectively determine whether there are obvious errors in the parameters of the grid-connected energy storage model provided by the manufacturer, so as to avoid incorrect conclusions from subsequent verification results.

[0084] Step S2, verifying the voltage support capability of the grid-type energy storage, calculating the voltage support capability index of the grid-type energy storage, and evaluating the voltage support capability of the grid-type energy storage. Specifically, the following steps are included:

[0085] Construct a system for connecting a grid-building energy storage to a planned power grid, where the planned power grid refers to the power grid that the grid-building energy storage will connect to at a planned time in the future. Set the node voltage of the grid-building energy storage to its rated voltage, and the active power and reactive power to 0.

[0086] For the planned power grid, the shortest path method is used to search for the shortest path l from the grid-type energy storage node to the i-th new energy station node i and the shortest electrical distance d i , i=1,2,…,N, where l i is the shortest path from the i-th new energy station to the grid-connected energy storage, and the shortest electrical distance d i Expressed in terms of reactance value, N is the number of new energy stations whose electrical distance around the grid-type energy storage is less than a given value L;

[0087] The shortest path l from the grid-type energy storage node to the i-th new energy station node i A single-phase instantaneous fault simulation is performed on the ith new energy station node to obtain the voltage after the fault. and the voltage during the fault Get the voltage difference

[0088] Replace the grid-connected energy storage with the grid-following energy storage and repeat the above simulation to obtain the voltage after the failure of the i-th new energy station node. and the voltage during the fault Get the voltage difference Calculate the voltage support capability index U of grid-connected energy storage s :

[0089]

[0090] U s The larger it is, the stronger the voltage support capability of the grid-type energy storage is.

[0091] Step S3, verifying the frequency support capability of the grid-type energy storage, calculating the frequency support capability index of the grid-type energy storage, and evaluating the frequency support capability of the grid-type energy storage. Specifically, the following steps are included:

[0092] For the planned power grid, the cut set method in graph theory is used to search for the electrical distance around the grid-forming energy storage node that is less than a given value D s The key section k j ={a1,a2,…,a m}, j = 1, 2, ..., M, where a m It belongs to the key section k j A circuit, m is a key section k j The number of lines, D s is the maximum allowable value of the electrical distance from the line belonging to the critical section to the grid-forming energy storage node, and M is the number of critical sections around the grid-forming energy storage node;

[0093] For the key section k jPerform line fault tripping simulation, that is, disconnect the critical section k j All lines {a1,a2,…,a m}, and obtain the pre-fault frequency of the grid-connected energy storage node and post-fault frequency And the frequency difference

[0094] Calculate the frequency support capability index F of grid-connected energy storage s :

[0095]

[0096] F s The larger the value, the stronger the frequency support capability of the grid-type energy storage.

[0097] Step S4, checking the capacity of the grid-type energy storage to determine whether the planned capacity of the grid-type energy storage is appropriate.

[0098] The specific steps include:

[0099] Increase the active power of all new energy stations in the planned power grid to their respective rated values, then increase the rated capacity of the grid-forming energy storage in the planned power grid, and then perform the single-phase instantaneous fault simulation to obtain the voltage difference between each new energy station node after and during the fault, and calculate the voltage support capability index of the grid-forming energy storage.

[0100] Repeat the above steps until the voltage support capability index of the grid-type energy storage is greater than the given value, and record the corresponding grid-type energy storage capacity value S Z .

[0101] Increase the active power of all new energy stations in the planned power grid to their respective rated values, then increase the rated capacity of the grid-forming energy storage in the planned power grid, and then perform a critical section line fault tripping simulation to obtain the frequency difference of the nodes of the grid-forming energy storage after the fault, and calculate the frequency support capability index of the grid-forming energy storage.

[0102] Repeat the above steps until the frequency support capability index of the grid-type energy storage is greater than the given value, and record the corresponding grid-type energy storage capacity value S F .

[0103] The planned capacity of grid-type energy storage S p With capacity value S z and S F contrast:

[0104] If S p >150%×S Z , and S p >150%×SF , indicating that the planned capacity value of grid-type energy storage is too large;

[0105] If 150%×S Z >S p >90%×S Z , and 150%×S F >S p >90%×S F , indicating that the planned capacity value of grid-type energy storage is appropriate;

[0106] If S p <90%×S Z , and S p <90%×S Z , indicating that the planned capacity value of grid-type energy storage is relatively small.

[0107] If the rated capacity of the grid-type energy storage is S p If the rated capacity S of the grid-type energy storage is too large, it means that the grid-type energy storage has an excellent effect in improving the stability of the system. p Suitable, indicating that the grid-type energy storage has a good effect in improving system stability. If the rated capacity of the grid-type energy storage is S p It is relatively small, indicating that the effect of the grid-type energy storage in improving system stability is average.

[0108] Embodiment 2:

[0109] like Figure 2 As shown, based on the same inventive concept as that of Example 1, this embodiment provides a verification system for improving the stability of a grid-connected energy storage system, which is applied to the method described, and includes:

[0110] The model verification module is used to verify the electromechanical transient simulation model of the grid-type energy storage, construct multiple operating scenarios and perform corresponding simulations, record the simulation results of several electrical quantity deviations of the grid-type energy storage, and determine whether there are errors in the grid-type energy storage model parameters provided by the manufacturer based on whether the several electrical quantity deviations exceed the corresponding deviation thresholds;

[0111] The voltage support capability verification module is used to verify the voltage support capability of the grid-type energy storage, calculate the voltage support capability index of the grid-type energy storage, and evaluate the voltage support capability of the grid-type energy storage;

[0112] The frequency support capability verification module is used to verify the frequency support capability of the grid-type energy storage, calculate the frequency support capability index of the grid-type energy storage, and evaluate the frequency support capability of the grid-type energy storage;

[0113] The capacity verification module verifies the capacity of the grid-type energy storage and determines whether the planned capacity of the grid-type energy storage is appropriate.

[0114] Embodiment 3:

[0115] Based on the same inventive concept as Example 1, this embodiment provides a computer-readable storage medium, which includes a stored program, wherein when the program is running, the device where the computer-readable storage medium is located is controlled to execute the method for verifying the stability of the grid-type energy storage system.

[0116] Embodiment 4:

[0117] Based on the same inventive concept as that of Example 1, this embodiment provides a processor, which is used to run a program, wherein when the program is running, the method for verifying the stability of the grid-connected energy storage system is executed.

[0118] Those of ordinary skill in the art will appreciate that the modules of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition of each example has been generally described in terms of function in the above description. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0119] In the embodiments provided by the present invention, it should be understood that the division of modules is only a logical function division, and there may be other division methods in actual implementation, for example, multiple modules can be combined into one module, one module can be split into multiple modules, or some features can be ignored, etc.

[0120] In addition, each functional module in each embodiment of the present invention may be integrated into one processing module, or each module may exist physically separately, or two or more modules may be integrated into one module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of software functional modules.

[0121] If the integrated module is implemented in the form of a software function module and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a server or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, read-only memory (ROM, Read-0nlyMemory), random access memory (RAM, RandomAccessMemory), mobile hard disk, magnetic disk or optical disk, etc., various media that can store program codes.

[0122] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and specification of the present invention.

Claims

1. A method for checking the stability of a grid-type energy storage system, characterized in that: The following steps are involved: Verify the electromechanical transient simulation model of the grid-type energy storage, build multiple operating scenarios and perform corresponding simulations, record the simulation results of several electrical quantity deviations of the grid-type energy storage, and determine whether there are errors in the grid-type energy storage model parameters provided by the manufacturer based on whether the several electrical quantity deviations exceed the corresponding deviation thresholds; Verify the voltage support capability of grid-type energy storage, calculate the voltage support capability index of grid-type energy storage, and evaluate the voltage support capability of grid-type energy storage; Verify the frequency support capability of grid-type energy storage, calculate the frequency support capability index of grid-type energy storage, and evaluate the frequency support capability of grid-type energy storage; Verify the capacity of the grid-type energy storage to determine whether the planned capacity of the grid-type energy storage is appropriate.

2. A method for checking the stability of a grid-type energy storage system according to claim 1, characterized in that: The construction of the working condition scenario and the corresponding simulation specifically include the following: (1) Build a single-machine infinite system of grid-connected energy storage and perform fault-free simulation and line tripping fault simulation; (2) Build a single-machine load system with grid-connected energy storage to simulate line tripping faults and load shedding small disturbance faults; (3) Build a system that connects grid-connected energy storage to the actual power grid to simulate line tripping faults, DC system bipolar blocking faults, and low voltage ride-through faults.

3. A method for checking the stability of a grid-type energy storage system according to claim 1, characterized in that: The simulation results of recording several electrical quantity deviations of the grid-type energy storage and judging whether the grid-type energy storage model parameters provided by the manufacturer are wrong are specifically as follows: The calculation formula of electrical quantity deviation is: where d i is the ith simulation data of the electrical quantity D, s i is the i-th corresponding reasonable data of the electrical quantity D; The electrical quantity D is the voltage, active power, reactive power and frequency of the grid-type energy storage, and the electrical quantity deviation ΔD includes the voltage deviation, active power deviation, reactive power deviation and frequency deviation of the grid-type energy storage; The judgment formula of whether the electrical quantity deviation exceeds the corresponding deviation threshold is: ΔD<δ D , where δ D is the deviation threshold; if all the electrical quantity deviations are less than the corresponding deviation threshold in all operating scenarios, proceed to the next step; if at least one electrical quantity deviation is greater than the corresponding deviation threshold in at least one operating scenario, do not proceed to the next step, first perform model parameter correction by the manufacturer or by itself, and then perform the electromechanical transient simulation model of the grid-type energy storage again, until all the electrical quantity deviations are less than the corresponding deviation threshold in all operating scenarios, and then proceed to the next step.

4. A method for checking the stability of a grid-type energy storage system according to claim 1, characterized in that: The checking of the voltage support capability of the grid-type energy storage, calculating the voltage support capability index of the grid-type energy storage, and evaluating the voltage support capability of the grid-type energy storage specifically include the following steps: Construct a system for connecting a grid-type energy storage to the planned power grid, and use the shortest path method to search for the shortest path l from the grid-type energy storage node to the i-th new energy station node. i and the shortest electrical distance d i , i=1,2,…,N, where l i is the shortest path from the i-th new energy station to the grid-connected energy storage, d i is the reactance value corresponding to the shortest path, and N is the number of new energy stations whose electrical distance around the grid-type energy storage is less than the given value L; The shortest path l from the grid-type energy storage node to the i-th new energy station node i The single-phase instantaneous fault simulation is performed on the ith new energy station node to obtain the voltage difference Δu after and during the fault. i ; Replace the grid-connected energy storage with the grid-following energy storage, and repeat the above simulation to obtain the voltage difference between the i-th new energy station node after and during the fault: Calculate the voltage support capability index U of grid-connected energy storage s : U s The larger it is, the stronger the voltage support capability of the grid-type energy storage is.

5. A method for checking the stability of a grid-type energy storage system according to claim 4, characterized in that: The checking of the frequency support capability of the grid-type energy storage, calculating the frequency support capability index of the grid-type energy storage, and evaluating the frequency support capability of the grid-type energy storage specifically include the following steps: Using the cut set method in graph theory, we search for nodes with electrical distances around them that are less than a given value D. s The key section k j ={a1,a2,…,a m }, j = 1, 2, ..., M, where a m It belongs to the key section k j A circuit, m is a key section k j The number of lines, D s is the maximum allowable value of the electrical distance from the line belonging to the critical section to the grid-forming energy storage node, and M is the number of critical sections around the grid-forming energy storage node; For the key section k j Perform line fault tripping simulation, that is, disconnect the critical section k j All lines {a1,a2,…,a m }, and obtain the frequency difference Δf of the grid-type energy storage node after the fault j ; Calculate the frequency support capability index F of grid-connected energy storage s : F s The larger the value, the stronger the frequency support capability of the grid-type energy storage.

6. A method for checking the stability of a grid-type energy storage system according to claim 1, characterized in that: The checking of the capacity of the grid-type energy storage to determine whether the planned capacity of the grid-type energy storage is appropriate specifically includes the following steps: Increase the rated capacity of the grid-type energy storage, calculate the voltage support capability index of the grid-type energy storage again, repeat the above steps until the voltage support capability index of the grid-type energy storage is greater than the given value, and record the corresponding grid-type energy storage capacity value S Z ; Increase the rated capacity of the grid-type energy storage, calculate the frequency support capability index of the grid-type energy storage again, repeat the above steps until the frequency support capability index of the grid-type energy storage is greater than the given value, and record the corresponding grid-type energy storage capacity value S F ; The planned capacity of grid-type energy storage S p With capacity value S Z and S F contrast: If S p >150%×S Z , and S p >150%×S F , indicating that the planned capacity value of grid-type energy storage is too large; If 150%×S Z >S p >90%×S Z , and 150%×S F >S p >90%×S F , indicating that the planned capacity value of grid-type energy storage is appropriate; If S p <90%×S Z , and S p <90%×S Z , indicating that the planned capacity value of grid-type energy storage is relatively small.

7. A verification system for improving the stability of a grid-type energy storage system, characterized in that: The method applied to any one of claims 1 to 6 comprises: The model verification module is used to verify the electromechanical transient simulation model of the grid-type energy storage, construct multiple operating scenarios and perform corresponding simulations, record the simulation results of several electrical quantity deviations of the grid-type energy storage, and determine whether there are errors in the grid-type energy storage model parameters provided by the manufacturer based on whether the several electrical quantity deviations exceed the corresponding deviation thresholds; The voltage support capability verification module is used to verify the voltage support capability of the grid-type energy storage, calculate the voltage support capability index of the grid-type energy storage, and evaluate the voltage support capability of the grid-type energy storage; The frequency support capability verification module is used to verify the frequency support capability of the grid-type energy storage, calculate the frequency support capability index of the grid-type energy storage, and evaluate the frequency support capability of the grid-type energy storage; The capacity verification module verifies the capacity of the grid-type energy storage and determines whether the planned capacity of the grid-type energy storage is appropriate.

8. A computer-readable storage medium, characterized in that: The computer-readable storage medium includes a stored program, wherein when the program is executed, the device where the computer-readable storage medium is located is controlled to execute the method for verifying the stability of a grid-type energy storage system according to any one of claims 1 to 6.

9. A processor, characterized in that: The processor is used to run a program, wherein when the program is running, the method for verifying the stability of a grid-connected energy storage system as described in any one of claims 1 to 6 is executed.

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