Method, device and equipment for enhancing transient stability of constructed network type energy storage and medium

Abstract

The invention discloses a method, a device, equipment and a medium for enhancing transient stability of networking type energy storage, and relates to the field of power electronic stability, and the method comprises the steps: carrying out the improvement of an active power control structure of initial networking type energy storage based on power deviation feedback and angular frequency deviation feedback, so as to obtain an improved control structure; determining a feedback compensation coefficient in the improved control structure according to the rated angular frequency of the power grid and the steady-state power angle of the network-building type energy storage before fault ride-through; and determining the transient power angle deviation of the network construction type energy storage during the fault ride-through period based on a nonlinear perturbation theory, and controlling the transient power angle deviation to be zero by using the feedback compensation coefficient and a preset constraint condition so as to enhance the transient stability of the network construction type energy storage. Therefore, the power angle fluctuation and the frequency fluctuation of the network construction type energy storage during the fault ride-through period can be greatly reduced, and the transient stability and the frequency stability of the network construction type energy storage are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of power electronic stability, and in particular to a network-constructed energy storage transient stability enhancement method, device, equipment and medium. BACKGROUND

[0002] The power electronic energy storage converter with network-constructed control has the functions of power support, inertia support, and wide frequency oscillation suppression, and thus is favored in new power systems and has been widely applied. However, due to the inherent characteristics of power electronic equipment, the network-constructed energy storage will face problems such as transient instability and current overload during power grid fault, which is not conducive to the safe and stable operation of power electronic equipment. Therefore, in order to enable the network-constructed energy storage to provide sufficient power support and inertia support during power grid fault, research on transient stability enhancement methods thereof needs to be carried out.

[0003] The existing network-constructed energy storage transient stability enhancement methods mainly have two ideas: 1) increasing the equivalent damping of the network-constructed energy storage control system to accelerate the transient attenuation process of the system, thereby enhancing the transient stability of the system without changing the original equilibrium point, but this method is not applicable to faults where the equilibrium point does not exist; 2) reducing the equivalent active power reference in the active power control loop to reduce the active power output of the network-constructed energy storage, which can not only reduce the fault current output of the network-constructed energy storage during fault ride-through, but also enhance its transient stability, which can be used for faults where the equilibrium point exists and for faults where the equilibrium point does not exist. However, the existing control methods can still be improved and perfected in the following aspects: 1) the control principle is complex, and frequent modification of control structure or control parameters is required under different power grid conditions or different fault conditions; 2) poor universality, making it difficult to achieve ideal control effect under different fault conditions; 3) no current limiting capability, or difficult to ensure the transient stability of the network-constructed energy storage in the current limiting mode; 4) the parameter design process is not rigorous, guided by small signal theory for nonlinear parameter design; 5) unable to balance transient stability and frequency stability. SUMMARY

[0004] Therefore, the purpose of the present application is to provide a network-constructed energy storage transient stability enhancement method, device, equipment and medium, which can make the power angle and frequency fluctuation of the network-constructed energy storage during fault ride-through almost zero, greatly improving the transient stability and frequency stability of the network-constructed energy storage, and having strong universality and simple control structure. The specific scheme is as follows:

[0005] In a first aspect, the present application discloses a network-constructed energy storage transient stability enhancement method, comprising:

[0006] The active power control structure of the initial grid-type energy storage is improved based on power deviation feedback and angular frequency deviation feedback to obtain the improved control structure.

[0007] The feedback compensation coefficient in the improved control structure is determined based on the grid's rated angular frequency and the steady-state power angle of the grid-type energy storage before fault crossing.

[0008] The transient power angle deviation of grid-type energy storage during fault ride is determined based on nonlinear perturbation theory. The transient power angle deviation is controlled to zero by the feedback compensation coefficient and preset constraints to enhance the transient stability of grid-type energy storage.

[0009] Optionally, before improving the active power control structure of the initial grid-type energy storage based on power deviation feedback and angular frequency deviation feedback, the method further includes:

[0010] After a grid fault, the grid connection point voltage of the grid-connected energy storage is detected, and the operation of improving the active power control structure of the initial grid-connected energy storage based on the degree of voltage drop at the grid connection point is determined according to the degree of voltage drop.

[0011] Alternatively, after a grid fault, determine whether the current limiting protection inside the grid-type energy storage device is activated, and determine whether to trigger the operation of improving the active power control structure of the initial grid-type energy storage based on power deviation feedback and angular frequency deviation feedback, according to the corresponding judgment result.

[0012] Optionally, the step of determining whether to trigger the improvement of the active power control structure of the initial grid-type energy storage based on the voltage drop at the grid connection point includes:

[0013] If the voltage drop at the grid connection point is less than or equal to a preset per-unit value, then the operation of improving the active power control structure of the initial grid-type energy storage based on power deviation feedback and angular frequency deviation feedback is prohibited.

[0014] If the voltage drop at the grid connection point is greater than the preset per-unit value, the operation of improving the active power control structure of the initial grid-type energy storage based on power deviation feedback and angular frequency deviation feedback is triggered.

[0015] Optionally, the step of determining whether to trigger the operation of improving the active power control structure of the initial grid-type energy storage based on power deviation feedback and angular frequency deviation feedback according to the corresponding judgment result includes:

[0016] If the current limiting protection inside the grid-type energy storage device is activated, it will trigger the operation of improving the active power control structure of the initial grid-type energy storage based on power deviation feedback and angular frequency deviation feedback.

[0017] Otherwise, the operation of improving the active power control structure of the initial grid-type energy storage based on power deviation feedback and angular frequency deviation feedback is prohibited.

[0018] Optionally, determining the feedback compensation coefficient in the improved control structure based on the grid's rated angular frequency and the steady-state power angle of the grid-type energy storage before fault crossing includes:

[0019] Determine the target product between the rated angular frequency of the power grid and the steady-state power angle of the grid-type energy storage before fault crossing;

[0020] The reciprocal of the target product is determined as the feedback compensation coefficient in the improved control structure.

[0021] Optionally, the determination of the transient power angle deviation of grid-type energy storage during fault ride-through based on nonlinear perturbation theory includes:

[0022] The transient power angle deviation during fault ride-through of grid-type energy storage is determined based on nonlinear perturbation theory using a transient power angle deviation determination formula. The transient power angle deviation determination formula is as follows:

[0023] ;

[0024] in, The transient power angle deviation is denoted by ; D is the damping coefficient of the grid-type energy storage; J is the virtual inertia of the grid-type energy storage. , , Let be the active power and the work angle deviation function respectively. The constant term, first-order Taylor coefficient, and second-order Taylor coefficient; As an intermediate variable; t is the rated angular frequency of the power grid; t is time. The first undetermined coefficient in the process of solving differential equations; These are the second undetermined coefficients in the process of solving differential equations; It is the natural vibration frequency; This refers to the rated power of the grid-type energy storage.

[0025] Optionally, before controlling the transient power angle deviation to zero using the feedback compensation coefficient and preset constraints, the method further includes:

[0026] Determine the difference between the rated power of the grid-type energy storage and the constant term of the active power-power angle deviation function, and determine the ratio between the difference and the first-order Taylor coefficient;

[0027] The ratio of 0 and the first undetermined coefficient of 0 in the process of solving the differential equation are determined as the preset constraint conditions.

[0028] Secondly, this application discloses a grid-type energy storage transient stability enhancement device, comprising:

[0029] The structural improvement module is used to improve the active power control structure of the initial grid-type energy storage based on power deviation feedback and angular frequency deviation feedback, so as to obtain the improved control structure.

[0030] The feedback compensation coefficient determination module is used to determine the feedback compensation coefficient in the improved control structure based on the grid rated angular frequency and the steady-state power angle of the grid-type energy storage before fault crossing.

[0031] The transient power angle deviation control module is used to determine the transient power angle deviation of grid-type energy storage during fault ride-through based on nonlinear perturbation theory, and to control the transient power angle deviation to zero using the feedback compensation coefficient and preset constraints, so as to enhance the transient stability of grid-type energy storage.

[0032] Thirdly, this application discloses an electronic device, including:

[0033] Memory, used to store computer programs;

[0034] A processor is used to execute computer programs to implement the steps of the aforementioned method for enhancing the transient stability of grid-type energy storage.

[0035] Fourthly, this application discloses a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the aforementioned method for enhancing the transient stability of grid-type energy storage.

[0036] This application improves the active power control structure of the initial grid-type energy storage based on power deviation feedback and angular frequency deviation feedback to obtain an improved control structure. The feedback compensation coefficient in the improved control structure is determined based on the grid's rated angular frequency and the steady-state power angle of the grid-type energy storage before fault ride-through. The transient power angle deviation of the grid-type energy storage during fault ride-through is determined based on nonlinear perturbation theory, and the transient power angle deviation is controlled to zero using the feedback compensation coefficient and preset constraints to enhance the transient stability of the grid-type energy storage. Therefore, this application proposes a feedback compensation control structure based on power and angular frequency deviations from the perspective of active power control loop reconfiguration, and provides a corresponding control parameter design scheme based on nonlinear perturbation theory. In this way, this application can significantly reduce the power angle and frequency fluctuations of grid-type energy storage during fault ride-through, making the power angle and frequency fluctuations of grid-type energy storage almost zero during fault ride-through. This greatly improves the transient stability and frequency stability of grid-type energy storage. Moreover, it has strong versatility and a simple control structure, and does not require adjustment of control parameters according to different fault conditions or control modes, which is conducive to engineering applications and provides guidance for the research and development of grid-type energy storage devices. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0038] Figure 1 This is a flowchart of a method for enhancing the transient stability of grid-type energy storage disclosed in this application;

[0039] Figure 2 This is a topology diagram of the active power control loop of a grid-type energy storage system disclosed in this application;

[0040] Figure 3 This is a schematic diagram illustrating the influence of a feedback compensation coefficient disclosed in this application on the transient power angle deviation and transient frequency deviation of grid-type energy storage;

[0041] Figure 4 This is a schematic diagram of a grid-type energy storage transient stability enhancement device disclosed in this application;

[0042] Figure 5 This is a structural diagram of an electronic device disclosed in this application. Detailed Implementation

[0043] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0044] Existing control methods can still be improved and perfected based on the following aspects: 1) The control principle is complex, requiring frequent correction of the control structure or control parameters under different grid operating conditions or different fault conditions; 2) The versatility is poor, making it difficult to achieve ideal control effects under different fault conditions; 3) It lacks current limiting capability, or it is difficult to guarantee the transient stability of grid-type energy storage under current limiting mode; 4) The parameter design process is not rigorous enough, relying on small-signal theory to guide the design of nonlinear parameters; 5) It fails to take into account both transient stability and frequency stability. To solve the above technical problems, this application discloses a method, device, equipment, and medium for enhancing the transient stability of grid-type energy storage, which enables the power angle and frequency fluctuations of grid-type energy storage to be almost zero during fault ride-through, greatly improving the transient stability and frequency stability of grid-type energy storage, and it has strong versatility and a simple control structure.

[0045] See Figure 1 As shown, this embodiment of the invention discloses a method for enhancing the transient stability of grid-type energy storage, including:

[0046] Step S11: Based on power deviation feedback and angular frequency deviation feedback, the active power control structure of the initial grid-type energy storage is improved to obtain the improved control structure.

[0047] In this embodiment, in actual engineering, it is necessary to determine whether to activate the transient stability enhancement method for grid-type energy storage based on power and angular frequency deviation feedback compensation control of the present invention, according to the actual fault conditions of the power grid. That is, to clarify the triggering conditions of the transient stability enhancement method in actual use: after a power grid fault, the grid connection point voltage of the grid-type energy storage is detected, and the degree of voltage drop at the grid connection point is used to determine whether to trigger the operation of improving the active power control structure of the initial grid-type energy storage based on power deviation feedback and angular frequency deviation feedback; or, after a power grid fault, it is determined whether the current limiting protection inside the grid-type energy storage device is activated, and the corresponding determination result is used to determine whether to trigger the operation of improving the active power control structure of the initial grid-type energy storage based on power deviation feedback and angular frequency deviation feedback. Specifically, if the voltage drop at the grid connection point is less than or equal to a preset per-unit value, the operation to improve the active power control structure of the initial grid-type energy storage based on power deviation feedback and angular frequency deviation feedback is prohibited. If the voltage drop at the grid connection point is greater than the preset per-unit value, the operation to improve the active power control structure of the initial grid-type energy storage based on power deviation feedback and angular frequency deviation feedback is triggered. If the current limiting protection inside the grid-type energy storage device is activated, the operation to improve the active power control structure of the initial grid-type energy storage based on power deviation feedback and angular frequency deviation feedback is triggered; otherwise, the operation to improve the active power control structure of the initial grid-type energy storage based on power deviation feedback and angular frequency deviation feedback is prohibited. In one specific embodiment, after a grid fault, the grid connection point voltage of the grid-connected energy storage is detected. If the voltage drop at the grid connection point is less than or equal to 0.2 Pu, the transient stability enhancement method of the present invention is not activated. After a grid fault, the grid connection point voltage of the grid-connected energy storage is detected. If the voltage drop at the grid connection point is greater than 0.2 Pu, the transient stability enhancement method of the present invention is activated. After a grid fault, if the current limiting protection inside the grid-connected energy storage device is triggered and the device is in current limiting operation mode, the transient stability enhancement method of the present invention is activated.

[0048] Next, the active power control loop of the grid-type energy storage is reconstructed. Based on power deviation feedback and angular frequency deviation feedback, the initial active power control structure of the grid-type energy storage is improved to obtain the improved control structure, as detailed below. Figure 2 The diagram shows a control structure based on power and angular frequency deviation feedback compensation. Here, s is the frequency domain Laplace operator; J is the virtual inertia of the grid-type energy storage; and D is the damping coefficient of the grid-type energy storage. ω is the rated angular frequency of the power grid; P is the output active power of the grid-type energy storage. The rated active power of grid-type energy storage; This is the feedback compensation coefficient.

[0049] Step S12: Determine the feedback compensation coefficient in the improved control structure based on the grid rated angular frequency and the steady-state power angle of the grid-type energy storage before fault crossing.

[0050] In this embodiment, a target product is determined between the rated angular frequency of the power grid and the steady-state power angle of the grid-type energy storage before fault crossing; the reciprocal of the target product is determined as the feedback compensation coefficient in the improved control structure. Specifically, in this application, the feedback compensation coefficient... The possible values ​​are as follows:

[0051] ;

[0052] in, This is the feedback compensation coefficient; The rated angular frequency of the power grid; The steady-state power angle of the grid-type energy storage before fault crossing.

[0053] Step S13: Determine the transient power angle deviation of grid-type energy storage during fault ride-through based on nonlinear perturbation theory, and control the transient power angle deviation to zero using the feedback compensation coefficient and preset constraints to enhance the transient stability of grid-type energy storage.

[0054] In this embodiment, the transient power angle deviation of the grid-type energy storage during fault ride-through is determined based on the nonlinear perturbation theory using a transient power angle deviation determination formula; the transient power angle deviation determination formula is as follows:

[0055] ;

[0056] in, The transient power angle deviation is denoted by ; D is the damping coefficient of the grid-type energy storage; J is the virtual inertia of the grid-type energy storage. , , Let be the active power and the work angle deviation function respectively. The constant term, first-order Taylor coefficient, and second-order Taylor coefficient; It has no explicit physical meaning; it is merely an intermediate variable in mathematical analysis, and its value is... ,in, , , These are the active power and work angle deviation functions, respectively. The constant term, first-order Taylor coefficient, and second-order Taylor coefficient of the Taylor expansion; t is the rated angular frequency of the power grid; t is time. The first undetermined coefficient in the process of solving differential equations; These are the second undetermined coefficients in the process of solving differential equations; It is the natural vibration frequency; This refers to the rated power of the grid-type energy storage.

[0057] In the transient work angle trajectory obtained above, the undetermined coefficients , The possible values ​​are as follows:

[0058] ;

[0059] in, It is the natural vibration frequency; , , These are the active power and work angle deviation functions, respectively. The constant term, first-order Taylor coefficient, and second-order Taylor coefficient; D is the damping coefficient of the grid-type energy storage; J is the virtual inertia of the grid-type energy storage. The rated power of grid-type energy storage; This is the rated angular frequency of the power grid.

[0060] From the expression for transient power angle deviation, it can be derived that, except for the last term... Each of the remaining vibration terms contains undetermined coefficients. Therefore, in order to make the power angle deviation and frequency deviation of the grid-type energy storage zero (substituting the constraints into the expression for transient power angle deviation shows that the power angle deviation is always zero, and the angular frequency deviation is the derivative of the power angle deviation, so its value is also zero), the following constraints need to be satisfied:

[0061] ;

[0062] in, The rated power of grid-type energy storage; , These are the active power and work angle deviation functions, respectively. The constant term and the first-order Taylor coefficient; These are the undetermined coefficients in the process of solving differential equations; The steady-state power angle deviation of the grid-type energy storage before fault crossing is 0.

[0063] It should be noted that, There are many expressions for the active power-power angle deviation function, mainly depending on the fault conditions of the power grid, such as symmetrical faults, asymmetrical faults, and converter current limiting. Only by clearly defining the fault type of the power grid can the accurate expression be known. For the method proposed in this application, it is not necessary to know the exact expression of the active power-power angle deviation function; it is only necessary to assume a function and then perform a Taylor expansion to obtain... , , That's it; in subsequent mathematical calculations, because it's set... =0, thus directly eliminating the influence of the difference in the active power-power angle deviation function, which also means that the method proposed in this application is applicable to a variety of fault types.

[0064] This involves determining the difference between the rated power of the grid-type energy storage and the constant term of the active power-power angle deviation function, and determining the ratio between this difference and the first-order Taylor coefficient. Setting this ratio to 0 and the first undetermined coefficient in the differential equation solution process to 0 are defined as the preset constraint conditions. Then, the feedback compensation coefficient and the preset constraint conditions can be used to control the transient power angle deviation to zero, thereby enhancing the transient stability of the grid-type energy storage.

[0065] As can be seen, this application proposes a feedback compensation control structure based on power and angular frequency deviations from the perspective of active power control loop reconfiguration, and provides a corresponding control parameter design scheme based on nonlinear perturbation theory. In this way, this application can significantly reduce the power angle and frequency fluctuations of grid-type energy storage during fault ride-through, making the power angle and frequency fluctuations of grid-type energy storage almost zero during fault ride-through. This greatly improves the transient stability and frequency stability of grid-type energy storage, and its versatility and simple control structure eliminate the need to adjust control parameters according to different fault conditions or control modes, facilitating engineering applications and providing guidance for the research and development of grid-type energy storage devices.

[0066] As described in the previous embodiment, this application discloses a method for enhancing the transient stability of grid-type energy storage, which can greatly improve the transient stability and frequency stability of grid-type energy storage. The implementation process of the specific method for enhancing the transient stability of grid-type energy storage will be explained in detail below.

[0067] This application first reconstructs the active power control loop of grid-type energy storage, and introduces... Figure 2 The diagram shows a control structure based on power and angular frequency deviation feedback compensation. Here, s is the frequency domain Laplace operator; J is the virtual inertia of the grid-type energy storage; and D is the damping coefficient of the grid-type energy storage. ω is the rated angular frequency of the power grid; P is the output active power of the grid-type energy storage. The rated active power of grid-type energy storage; The feedback compensation coefficient is used. Based on nonlinear perturbation theory, the transient power angle deviation of grid-type energy storage during fault ride-through is characterized as follows:

[0068] ;

[0069] in, The transient power angle deviation is denoted by ; D is the damping coefficient of the grid-type energy storage; J is the virtual inertia of the grid-type energy storage. , , Let be the active power and the work angle deviation function respectively. The constant term, first-order Taylor coefficient, and second-order Taylor coefficient; It has no explicit physical meaning; it is merely an intermediate variable in mathematical analysis, and its value is... ; t is the rated angular frequency of the power grid; t is time. The first undetermined coefficient in the process of solving differential equations; These are the second undetermined coefficients in the process of solving differential equations; It is the natural vibration frequency; This refers to the rated power of the grid-type energy storage.

[0070] In the transient work angle trajectory obtained in the previous step, the undetermined coefficients , The possible values ​​are as follows:

[0071] ;

[0072] in, It is the natural vibration frequency; , , These are the active power and work angle deviation functions, respectively. The constant term, first-order Taylor coefficient, and second-order Taylor coefficient; D is the damping coefficient of the grid-type energy storage; J is the virtual inertia of the grid-type energy storage. The rated power of grid-type energy storage; This is the rated angular frequency of the power grid.

[0073] Introduction Figure 2 The active power-power angle deviation function after compensation feedback control is shown. The specific expression is subject to the feedback compensation coefficient. The impact, through reasonable correction The value can be changed , , The value of is used to reshape the power angle deviation trajectory of grid-type energy storage. Among them... Figure 3 Different feedback compensation coefficients were shown. To address the impact of power angle and frequency deviations during transient processes in grid-type energy storage, optimal transient and frequency stability requires appropriate settings. The value of makes the power angle deviation and frequency deviation zero. From the expression for transient power angle deviation, we can derive that, except for the last term... Each of the remaining vibration terms contains undetermined coefficients. Therefore, the following constraints must be met to ensure that the power angle deviation and frequency deviation of the grid-type energy storage are zero:

[0074] ;

[0075] in, The rated power of grid-type energy storage; , These are the active power and work angle deviation functions, respectively. The constant term and the first-order Taylor coefficient; These are the undetermined coefficients in the process of solving differential equations; The steady-state power angle deviation of the grid-type energy storage before fault crossing is 0.

[0076] Based on the constraints in the previous step, the feedback compensation coefficient can be obtained. The possible values ​​are as follows:

[0077] ;

[0078] in, This is the feedback compensation coefficient; The rated angular frequency of the power grid; The steady-state power angle of the grid-type energy storage before fault crossing.

[0079] Finally, the transient power angle deviation is controlled to zero by using the feedback compensation coefficient and preset constraints to enhance the transient stability of grid-type energy storage.

[0080] As can be seen, this application optimizes and reconstructs the active power control loop of grid-type energy storage, develops a feedback compensation control structure based on power and angular frequency deviations, and then, based on nonlinear perturbation theory, presents a method for designing control parameters with the goal of minimizing power angle fluctuations and frequency fluctuations (while considering the transient stability and frequency stability of grid-type energy storage during fault ride-through). This method for enhancing the transient stability of grid-type energy storage has the following three advantages over existing methods: 1) The control structure is simple, and when the compensation coefficient... Once the value is determined, it no longer needs to be adjusted in real time according to different fault conditions or control modes, and has good versatility and is easy to implement in engineering; 2) It can achieve ideal control effect under different fault conditions or equipment operation modes (such as symmetrical faults, asymmetrical faults, current limiting mode, etc.); 3) It can significantly reduce the power angle fluctuation and frequency fluctuation of grid-type energy storage during fault ride-through, and has extremely strong transient stability and frequency stability.

[0081] See Figure 4 As shown, an embodiment of the present invention discloses a grid-type energy storage transient stability enhancement device, comprising:

[0082] The structural improvement module 11 is used to improve the active power control structure of the initial grid-type energy storage based on power deviation feedback and angular frequency deviation feedback, so as to obtain the improved control structure.

[0083] The feedback compensation coefficient determination module 12 is used to determine the feedback compensation coefficient in the improved control structure based on the grid rated angular frequency and the steady-state power angle of the grid-type energy storage before fault crossing.

[0084] The transient power angle deviation control module 13 is used to determine the transient power angle deviation of grid-type energy storage during fault ride-through based on nonlinear perturbation theory, and to control the transient power angle deviation to zero using the feedback compensation coefficient and preset constraints, so as to enhance the transient stability of grid-type energy storage.

[0085] As can be seen, this application proposes a feedback compensation control structure based on power and angular frequency deviations from the perspective of active power control loop reconfiguration, and provides a corresponding control parameter design scheme based on nonlinear perturbation theory. In this way, this application can significantly reduce the power angle and frequency fluctuations of grid-type energy storage during fault ride-through, making the power angle and frequency fluctuations of grid-type energy storage almost zero during fault ride-through. This greatly improves the transient stability and frequency stability of grid-type energy storage, and its versatility and simple control structure eliminate the need to adjust control parameters according to different fault conditions or control modes, facilitating engineering applications and providing guidance for the research and development of grid-type energy storage devices.

[0086] In some specific embodiments, the device can also be used to detect the grid connection point voltage of the grid-connected energy storage after a grid fault, and determine whether to trigger the operation of improving the active power control structure of the initial grid-connected energy storage based on the degree of voltage drop at the grid connection point; or, after a grid fault, determine whether the current limiting protection inside the grid-connected energy storage device is activated, and determine whether to trigger the operation of improving the active power control structure of the initial grid-connected energy storage based on the corresponding judgment result.

[0087] In some specific embodiments, the structure improvement module 11 can be used to prevent the operation of improving the active power control structure of the initial grid-type energy storage based on power deviation feedback and angular frequency deviation feedback from being triggered if the voltage drop at the grid connection point is less than or equal to a preset per-unit value; and to trigger the operation of improving the active power control structure of the initial grid-type energy storage based on power deviation feedback and angular frequency deviation feedback if the voltage drop at the grid connection point is greater than the preset per-unit value.

[0088] In some specific embodiments, the structure improvement module 11 can be used to trigger the operation of improving the active power control structure of the initial grid-type energy storage based on power deviation feedback and angular frequency deviation feedback if the current limiting protection inside the grid-type energy storage device is activated; otherwise, the operation of improving the active power control structure of the initial grid-type energy storage based on power deviation feedback and angular frequency deviation feedback is prohibited.

[0089] In some specific embodiments, the feedback compensation coefficient determination module 12 can be used to determine the target product between the grid rated angular frequency and the steady-state power angle of the grid-type energy storage before fault crossing; and the reciprocal of the target product is determined as the feedback compensation coefficient in the improved control structure.

[0090] In some specific embodiments, the transient power angle deviation control module 13 can be used to determine the transient power angle deviation of grid-type energy storage during fault ride-through based on nonlinear perturbation theory using a transient power angle deviation determination formula; the transient power angle deviation determination formula is:

[0091] ;

[0092] in, The transient power angle deviation is denoted by ; D is the damping coefficient of the grid-type energy storage; J is the virtual inertia of the grid-type energy storage. , , Let be the active power and the work angle deviation function respectively. The constant term, first-order Taylor coefficient, and second-order Taylor coefficient; As an intermediate variable; t is the rated angular frequency of the power grid; t is time. The first undetermined coefficient in the process of solving differential equations; These are the second undetermined coefficients in the process of solving differential equations; It is the natural vibration frequency; This refers to the rated power of the grid-type energy storage.

[0093] In some specific embodiments, the device can also be used to determine the difference between the rated power of the grid-type energy storage and the constant term of the active power-power angle deviation function, and to determine the ratio between the difference and the first-order Taylor coefficient; the ratio being 0 and the first undetermined coefficient being 0 in the process of solving the differential equation are determined as the preset constraint conditions.

[0094] Furthermore, embodiments of this application also disclose an electronic device, Figure 5 This is a structural diagram of an electronic device 20 according to an exemplary embodiment. The content of the diagram should not be construed as limiting the scope of this application.

[0095] Figure 5 This is a schematic diagram of the structure of an electronic device 20 provided in an embodiment of this application. Specifically, the electronic device 20 may include: at least one processor 21, at least one memory 22, a power supply 23, a communication interface 24, an input / output interface 25, and a communication bus 26. The memory 22 stores a computer program, which is loaded and executed by the processor 21 to implement the relevant steps in the network-type energy storage transient stability enhancement method disclosed in any of the foregoing embodiments. Alternatively, the electronic device 20 in this embodiment may specifically be an electronic computer.

[0096] In this embodiment, the power supply 23 is used to provide operating voltage for each hardware device on the electronic device 20; the communication interface 24 can create a data transmission channel between the electronic device 20 and external devices, and the communication protocol it follows can be any communication protocol applicable to the technical solution of this application, and is not specifically limited here; the input / output interface 25 is used to acquire external input data or output data to the outside world, and its specific interface type can be selected according to specific application needs, and is not specifically limited here.

[0097] In addition, the memory 22, as a carrier for resource storage, can be a read-only memory, random access memory, disk or optical disk, etc. The resources stored thereon can include operating system 221, computer program 222, etc., and the storage method can be temporary storage or permanent storage.

[0098] The operating system 221 is used to manage and control the various hardware devices on the electronic device 20 and the computer program 222, which may be Windows Server, Netware, Unix, Linux, etc. In addition to including a computer program capable of performing the network-type energy storage transient stability enhancement method executed by the electronic device 20 as disclosed in any of the foregoing embodiments, the computer program 222 may further include a computer program capable of performing other specific tasks.

[0099] Furthermore, this application also discloses a computer-readable storage medium for storing a computer program; wherein, when the computer program is executed by a processor, it implements the aforementioned method for enhancing the transient stability of grid-type energy storage. Specific steps of this method can be found in the corresponding content disclosed in the foregoing embodiments, and will not be repeated here.

[0100] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to in the method section.

[0101] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0102] The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein can be implemented directly by hardware, a software module executed by a processor, or a combination of both. The software module can be located in random access memory (RAM), main memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art.

[0103] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0104] The technical solutions provided in this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A method for enhancing the transient stability of grid-type energy storage, characterized in that, include: The active power control structure of the initial grid-type energy storage is improved based on power deviation feedback and angular frequency deviation feedback to obtain the improved control structure. The feedback compensation coefficient in the improved control structure is determined based on the grid's rated angular frequency and the steady-state power angle of the grid-type energy storage before fault crossing. The transient power angle deviation of grid-type energy storage during fault ride is determined based on nonlinear perturbation theory. The transient power angle deviation is controlled to zero by the feedback compensation coefficient and preset constraints to enhance the transient stability of grid-type energy storage.

2. The method for enhancing the transient stability of grid-type energy storage according to claim 1, characterized in that, Before improving the active power control structure of the initial grid-type energy storage based on power deviation feedback and angular frequency deviation feedback, it also includes: After a grid fault, the grid connection point voltage of the grid-connected energy storage is detected, and the operation of improving the active power control structure of the initial grid-connected energy storage based on the degree of voltage drop at the grid connection point is determined according to the degree of voltage drop. Alternatively, after a grid fault, determine whether the current limiting protection inside the grid-type energy storage device is activated, and determine whether to trigger the operation of improving the active power control structure of the initial grid-type energy storage based on power deviation feedback and angular frequency deviation feedback, according to the corresponding judgment result.

3. The method for enhancing the transient stability of grid-type energy storage according to claim 2, characterized in that, The operation of determining whether to trigger the improvement of the active power control structure of the initial grid-type energy storage based on the voltage drop at the grid connection point includes: If the voltage drop at the grid connection point is less than or equal to a preset per-unit value, then the operation of improving the active power control structure of the initial grid-type energy storage based on power deviation feedback and angular frequency deviation feedback is prohibited. If the voltage drop at the grid connection point is greater than the preset per-unit value, the operation of improving the active power control structure of the initial grid-type energy storage based on power deviation feedback and angular frequency deviation feedback is triggered.

4. The method for enhancing the transient stability of grid-type energy storage according to claim 2, characterized in that, The operation of determining whether to trigger the improvement of the active power control structure of the initial grid-type energy storage based on power deviation feedback and angular frequency deviation feedback according to the corresponding judgment result includes: If the current limiting protection inside the grid-type energy storage device is activated, it will trigger the operation of improving the active power control structure of the initial grid-type energy storage based on power deviation feedback and angular frequency deviation feedback. Otherwise, the operation of improving the active power control structure of the initial grid-type energy storage based on power deviation feedback and angular frequency deviation feedback is prohibited.

5. The method for enhancing the transient stability of grid-type energy storage according to claim 1, characterized in that, The determination of the feedback compensation coefficient in the improved control structure based on the grid's rated angular frequency and the steady-state power angle of the grid-type energy storage before fault crossing includes: Determine the target product between the rated angular frequency of the power grid and the steady-state power angle of the grid-type energy storage before fault crossing; The reciprocal of the target product is determined as the feedback compensation coefficient in the improved control structure.

6. The method for enhancing the transient stability of grid-type energy storage according to any one of claims 1 to 5, characterized in that, The determination of transient power angle deviation during fault ride-through of grid-type energy storage based on nonlinear perturbation theory includes: The transient power angle deviation during fault ride-through of grid-type energy storage is determined based on nonlinear perturbation theory using a transient power angle deviation determination formula. The transient power angle deviation determination formula is as follows: ； in, The transient power angle deviation is denoted by ; D is the damping coefficient of the grid-type energy storage; J is the virtual inertia of the grid-type energy storage. , , Let be the active power and the work angle deviation function respectively. The constant term, first-order Taylor coefficient, and second-order Taylor coefficient; As an intermediate variable; t is the rated angular frequency of the power grid; t is time. The first undetermined coefficient in the process of solving differential equations; These are the second undetermined coefficients in the process of solving differential equations; It is the natural vibration frequency; This refers to the rated power of the grid-type energy storage.

7. The method for enhancing the transient stability of grid-type energy storage according to claim 6, characterized in that, Before controlling the transient power angle deviation to zero using the feedback compensation coefficient and preset constraints, the method further includes: Determine the difference between the rated power of the grid-type energy storage and the constant term of the active power-power angle deviation function, and determine the ratio between the difference and the first-order Taylor coefficient; The ratio of 0 and the first undetermined coefficient of 0 in the process of solving the differential equation are determined as the preset constraint conditions.

8. A grid-type energy storage transient stability enhancement device, characterized in that, include: The structural improvement module is used to improve the active power control structure of the initial grid-type energy storage based on power deviation feedback and angular frequency deviation feedback, so as to obtain the improved control structure. The feedback compensation coefficient determination module is used to determine the feedback compensation coefficient in the improved control structure based on the grid rated angular frequency and the steady-state power angle of the grid-type energy storage before fault crossing. The transient power angle deviation control module is used to determine the transient power angle deviation of grid-type energy storage during fault ride-through based on nonlinear perturbation theory, and to control the transient power angle deviation to zero using the feedback compensation coefficient and preset constraints, so as to enhance the transient stability of grid-type energy storage.

9. An electronic device, characterized in that, include: Memory, used to store computer programs; A processor for executing a computer program to implement the steps of the method for enhancing the transient stability of grid-type energy storage as described in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, A computer program is stored on a computer-readable storage medium, and when executed by a processor, the computer program implements the steps of the method for enhancing the transient stability of grid-type energy storage as described in any one of claims 1 to 7.

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