Active power determination method, device and equipment under fault of new energy access receiving end power grid, and medium

Abstract

The invention discloses an active power determination method, device, equipment and medium under a new energy access receiving end power grid fault, and relates to the technical field of new energy power generation, and the method comprises the steps: obtaining an equivalent circuit diagram of a grid-side converter when a new energy system is connected to a receiving end of an extra-high voltage DC power transmission system, and determining a target parameter based on the equivalent circuit diagram; determining a first voltage component of the grid-side converter and a first current component output to a receiving-end power grid in a steady state before the fault occurs, and determining a second voltage component of the grid-side converter and a second current component output to the receiving-end power grid after the power grid fault occurs based on the target parameters; determining a third current component output to the receiving-end power grid by the grid-side converter according to the target parameter; and determining the active power output to the receiving end power grid by the new energy system through the first voltage component, the first current component, the second voltage component, the second current component and the third current component. The method can accurately calculate the active power output to the power grid by the new energy unit under the power grid fault condition.

Description

Technical Field

[0001] This invention relates to the field of new energy power generation technology, and in particular to a method, apparatus, equipment and medium for determining active power under fault conditions when new energy is connected to the receiving-end grid. Background Technology

[0002] Ultra-high voltage (UHV) power transmission technology, with its advantages of environmental friendliness, high efficiency, large capacity, and long-distance transmission, plays a crucial role in promoting the West-to-East Power Transmission Project and building interconnected power grids. UHVDC transmission not only overcomes the limitations of synchronous operation stability but also boasts significant advantages such as low line loss, large transmission capacity, and rapid power regulation, demonstrating extremely broad application prospects. However, the large-scale integration of renewable energy units into the UHVDC receiving-end system also brings many adverse effects to the safe and stable operation of the receiving-end system. Common DC transmission faults can cause voltage fault characteristics in the receiving-end grid with large-scale renewable energy integration, exhibiting a high-voltage surge followed by a low-voltage surge. To better understand the characteristics of the receiving-end grid under fault conditions, it is necessary to accurately obtain the transient active power response characteristics of renewable energy units under fault conditions. Existing methods are often only applicable to analyzing the transient characteristics of renewable energy units after integration under step faults in the grid, and cannot be applied to the transient operation characteristics analysis of renewable energy units in the receiving-end grid under non-step faults such as commutation failures in UHVDC. Summary of the Invention

[0003] In view of this, the purpose of this invention is to provide a method, apparatus, equipment, and medium for determining the active power of new energy units under grid fault conditions, applicable to different grid voltage fault states and considering different converter control parameters, thereby calculating the active power output of new energy units to the grid under grid fault conditions. The specific solution is as follows:

[0004] In a first aspect, this application discloses a method for determining active power under grid fault conditions when new energy sources are connected to the receiving end of the grid, including:

[0005] Obtain the equivalent circuit diagram of the grid-side converter when the new energy system is connected to the UHVDC transmission system at the receiving end, and determine the target parameters based on the equivalent circuit diagram. The target parameters include the phase voltage amplitude of the receiving-end grid, the phase current amplitude output to the receiving-end grid, the current component of the grid-side converter input to the receiving-end grid on the dq axis, the current component of the grid-side converter output to the resistor-capacitor filter branch on the dq axis, the current component of the grid-side converter output to the receiving-end grid on the q axis under steady state before the fault occurs, the rotational angular velocity corresponding to the grid voltage frequency, and the filter inductance.

[0006] The first voltage component of the grid-side converter and the first current component output to the receiving-end grid under steady state before the fault occurs are determined, and the second voltage component of the grid-side converter and the second current component output to the receiving-end grid are determined based on the target parameters after the grid fault occurs.

[0007] The third current component output from the grid-side converter to the receiving-end grid is determined based on the target parameters.

[0008] The active power output from the new energy system to the receiving-end grid is determined by the first voltage component, the first current component, the second voltage component, the second current component, and the third current component.

[0009] Optionally, determining the first voltage component of the grid-side converter and the first current component output to the receiving-end grid under steady-state conditions before the fault occurs includes:

[0010] The phase voltage amplitude of the receiving-end power grid is determined as the first voltage component of the grid-side converter under steady-state conditions before the fault occurs.

[0011] The amplitude of the phase current output to the receiving-end grid is determined as the first current component output by the grid-side converter to the receiving-end grid under steady-state conditions before the fault occurs.

[0012] Optionally, determining the second voltage component of the grid-side converter and the second current component output to the receiving-end grid after a grid fault occurs based on the target parameters includes:

[0013] The fitting function of the receiving-end grid voltage is determined as the second voltage component of the grid-side converter after a grid fault occurs;

[0014] Determine the first difference between the current component input from the grid-side converter to the receiving-end grid on the d-axis and the current component output from the grid-side converter to the resistor-capacitor filter branch on the d-axis;

[0015] The first difference is determined as the second current component output by the grid-side converter to the receiving-end grid after a grid fault occurs.

[0016] Optionally, before determining the third current component output from the grid-side converter to the receiving-end grid based on the target parameters, the method further includes:

[0017] Determine a second difference between the current component input from the grid-side converter to the receiving-end grid on the q-axis and the current component output from the grid-side converter to the resistor-capacitor filter branch on the q-axis;

[0018] The second difference is determined as the current component output by the grid-side converter to the receiving-end grid after a grid fault occurs.

[0019] Optionally, determining the third current component output from the grid-side converter to the receiving-end grid based on the target parameters includes:

[0020] The target current is determined based on the target parameters using a preset target current determination formula; the preset target current determination formula is:

[0021] ;

[0022] in, The target current in the complex frequency domain; This is the transfer function of the d-axis current loop controller; This is the d-axis current command value; The current component output from the grid-side converter to the receiving-end grid on the q-axis under steady-state conditions before the fault occurs; This is the second current component in the complex frequency domain; The rotational angular velocity corresponding to the grid voltage frequency; For filtering inductors; is the current component output from the grid-side converter to the receiving-end grid on the q-axis after a grid fault occurs in the complex frequency domain; s is a complex variable in the complex frequency domain;

[0023] The third current component output by the grid-side converter to the receiving-end grid is determined based on the target current.

[0024] Optionally, determining the third current component output from the grid-side converter to the receiving-end grid based on the target current includes:

[0025] The target current is subjected to an inverse Laplace transform to obtain the third current component output by the grid-side converter to the receiving-end grid.

[0026] Optionally, determining the active power output from the renewable energy system to the receiving-end grid using the first voltage component, the first current component, the second voltage component, the second current component, and the third current component includes:

[0027] The active power output from the new energy system to the receiving-end power grid is determined by a preset active power determination formula; the preset active power determination formula is as follows:

[0028] ;

[0029] ;

[0030] in, The active power; The grid voltage component on the d-axis; The current component output from the grid-side converter to the receiving-end grid on the d-axis; This refers to the first voltage component; This refers to the first current component; This is the second voltage component; This is the second current component; This refers to the third current component.

[0031] Secondly, this application discloses a device for determining active power under grid fault conditions when new energy sources are connected to the receiving end of the grid, comprising:

[0032] The parameter determination module is used to obtain the equivalent circuit diagram of the grid-side converter when the new energy system is connected to the UHVDC transmission system at the receiving end, and to determine the target parameters based on the equivalent circuit diagram. The target parameters include the phase voltage amplitude of the receiving-end grid, the phase current amplitude output to the receiving-end grid, the current component of the grid-side converter input to the receiving-end grid on the dq axis, the current component of the grid-side converter output to the resistor-capacitor filter branch on the dq axis, the current component of the grid-side converter output to the receiving-end grid on the q axis under steady state before the fault occurs, the rotational angular velocity corresponding to the grid voltage frequency, and the filter inductance.

[0033] The first component determination module is used to determine the first voltage component of the grid-side converter and the first current component output to the receiving-end grid under steady-state conditions before the fault occurs.

[0034] The second component determination module is used to determine the second voltage component of the grid-side converter and the second current component output to the receiving-end grid after a grid fault occurs, based on the target parameters.

[0035] The third component determination module is used to determine the third current component output from the grid-side converter to the receiving-end grid based on the target parameters.

[0036] The active power determination module is used to determine the active power output from the new energy system to the receiving-end grid through the first voltage component, the first current component, the second voltage component, the second current component, and the third current component.

[0037] Thirdly, this application discloses an electronic device, including:

[0038] Memory, used to store computer programs;

[0039] The processor is used to execute computer programs to implement the method for determining active power under grid fault conditions at the receiving end of the new energy access, as described above.

[0040] Fourthly, this application discloses a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the aforementioned method for determining active power under grid faults at the receiving end of new energy access.

[0041] This application first obtains the equivalent circuit diagram of the grid-side converter when the new energy system is connected to the UHVDC transmission system at the receiving end, and determines the target parameters based on the equivalent circuit diagram. The target parameters include the phase voltage amplitude of the receiving-end grid, the phase current amplitude output to the receiving-end grid, the current component input from the grid-side converter to the receiving-end grid on the dq axis, the current component output from the grid-side converter to the resistor-capacitor filter branch on the dq axis, the current component output from the grid-side converter to the receiving-end grid on the q axis under steady-state conditions before the fault, and the rotational angular velocity corresponding to the grid voltage frequency. The process involves: determining the first voltage component of the grid-side converter and the first current component output to the receiving-end grid under steady-state conditions before a fault occurs; determining the second voltage component of the grid-side converter and the second current component output to the receiving-end grid after a grid fault occurs based on the target parameters; determining the third current component output by the grid-side converter to the receiving-end grid according to the target parameters; and finally determining the active power output of the renewable energy system to the receiving-end grid using the first voltage component, the first current component, the second voltage component, the second current component, and the third current component. This application employs the superposition theorem to divide the transient active power response calculation under receiving-end grid faults into three states: steady-state before a fault occurs, the state of grid voltage change after a fault occurs, and the state of grid-side converter output voltage change after a fault occurs. The active power is ultimately determined based on these three state components. This method can be applied to different grid voltage fault states and considers different converter control parameters to accurately calculate the active power output of the UHVDC receiving-end renewable energy system to the grid after common DC transmission faults. Attached Figure Description

[0042] 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.

[0043] Figure 1 This application discloses a flowchart of a method for determining active power under grid fault conditions when new energy sources are connected to the receiving end of the grid.

[0044] Figure 2 This application discloses an equivalent circuit diagram of a new energy system connected to an ultra-high voltage direct current receiving-end grid converter.

[0045] Figure 3 This is a schematic diagram comparing the simulation model and mathematical model of the active power output of a new energy system under fault conditions disclosed in this application;

[0046] Figure 4This is a schematic diagram comparing the simulation model and mathematical model of the d-axis voltage under fault conditions disclosed in this application.

[0047] Figure 5 This is a schematic diagram comparing the simulation model and mathematical model of the d-axis current under fault conditions disclosed in this application.

[0048] Figure 6 This is a schematic diagram of the active power determination device under grid fault conditions at the receiving end of a new energy source, as disclosed in this application.

[0049] Figure 7 This is a structural diagram of an electronic device disclosed in this application. Detailed Implementation

[0050] 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.

[0051] Common DC transmission faults can cause voltage fault characteristics in the receiving-end grid of large-scale renewable energy grid integration, characterized by a high-voltage surge followed by a low-voltage surge. To better understand the characteristics of the receiving-end grid under fault conditions, it is necessary to accurately obtain the transient active power response characteristics of renewable energy units under these conditions. Existing methods are often only applicable to analyzing the transient characteristics of renewable energy units after grid connection under step faults, and cannot be applied to the transient operation characteristics analysis of renewable energy units in the receiving-end grid under non-step faults such as commutation failures in UHVDC transmission. To solve the above technical problems, this application discloses a method, device, equipment, and medium for determining the active power under faults in renewable energy grid connection at the receiving end. This method can be applied to the active power of renewable energy units under different grid voltage fault states and considering different converter control parameters, thereby calculating the active power output of renewable energy units to the grid under grid fault conditions.

[0052] See Figure 1 As shown in the figure, this invention discloses a method for determining active power under grid fault conditions when new energy sources are connected to the receiving end of the grid, including:

[0053] Step S11: Obtain the equivalent circuit diagram of the grid-side converter when the new energy system is connected to the UHVDC transmission system at the receiving end, and determine the target parameters based on the equivalent circuit diagram. The target parameters include the phase voltage amplitude of the receiving end grid, the phase current amplitude output to the receiving end grid, the current component input from the grid-side converter to the receiving end grid on the dq axis, the current component output from the grid-side converter to the resistor-capacitor filter branch on the dq axis, the current component output from the grid-side converter to the receiving end grid on the q axis under steady state before the fault occurs, the rotational angular velocity corresponding to the grid voltage frequency, and the filter inductance.

[0054] In this embodiment, firstly, the equivalent circuit diagram of the grid-side converter of the new energy system connected to the UHVDC receiving end is obtained, such as... Figure 2 As shown, the target parameters can be determined based on the equivalent circuit diagram. These target parameters include the phase voltage amplitude of the receiving-end grid, the phase current amplitude output to the receiving-end grid, the current component input from the grid-side converter to the receiving-end grid on the dq axis, the current component output from the grid-side converter to the resistor-capacitor filter branch on the dq axis, the current component output from the grid-side converter to the receiving-end grid on the q axis under steady-state conditions before the fault occurs, the rotational angular velocity corresponding to the grid voltage frequency, and the filter inductance.

[0055] Step S12: Determine the first voltage component of the grid-side converter and the first current component output to the receiving-end grid under steady state before the fault occurs, and determine the second voltage component of the grid-side converter and the second current component output to the receiving-end grid after the grid fault occurs based on the target parameters.

[0056] In this embodiment, based on the superposition theorem of power sources, the transient response calculation of the new energy system under fault conditions is divided into three state components: the state before the fault, the state of grid voltage change, and the state of grid-side converter output voltage change. Therefore, the first voltage component of the grid-side converter and the first current component output to the receiving-end grid under steady-state conditions before the fault are first determined. In this process, the phase voltage amplitude of the receiving-end grid is determined as the first voltage component of the grid-side converter under steady-state conditions before the fault; the phase current amplitude output to the receiving-end grid is determined as the first current component output from the grid-side converter to the receiving-end grid under steady-state conditions before the fault. Specifically, the steady-state grid-side converter voltage and current before the fault can be expressed as:

[0057] ;

[0058] ;

[0059] in, For filtering inductors, For filtering capacitors, For filtering resistors; and These represent the grid voltage component and the current component output to the grid on the dq axis, respectively. , , and These represent the voltage component of the GSC (Grid Side Converter) and the current component of the GSC output on the dq axis, respectively. and These are the current components output on the dq axis to the RC (Resistor-Capacitor) filter branch; This refers to the phase voltage amplitude of the power grid. The amplitude of the phase current output to the power grid; The rotational angular velocity corresponds to the grid voltage frequency; the subscript 0 indicates that it is the voltage and current components in steady state before the commutation failure. Furthermore, the above formulas demonstrate the model's systematicity and scalability, facilitating the addition of more influencing factors in the future.

[0060] Furthermore, after a grid fault occurs, considering only the voltage change of the receiving-end grid, the fitted function of the receiving-end grid voltage is determined as the second voltage component of the grid-side converter after the grid fault. A first difference is determined between the current component input from the grid-side converter to the receiving-end grid on the d-axis and the current component output from the grid-side converter to the resistor-capacitor filter branch on the d-axis. This first difference is determined as the second current component output from the grid-side converter to the receiving-end grid after the grid fault. Specifically, the current input to the grid can be expressed as (subscript 1 indicates the voltage and current components input to the grid considering only the voltage change of the receiving-end grid):

[0061] ;

[0062] Under grid voltage-oriented vector control, the grid voltage can be expressed as:

[0063] ;

[0064] This indicates that the grid voltage is a time function with arbitrary amplitude variation (a fitted function of the receiving-end grid voltage). Uppercase symbols (e.g., U, I) in the formula represent: steady-state value, rated value, amplitude, or DC component. Lowercase symbols (e.g., u, i) represent: instantaneous value or a quantity that changes with time. and These represent the grid voltage component and the current component output to the grid on the dq axis, respectively. and These are the GSC voltage component and the GSC output current component on the dq axis, respectively. and These are the current components output to the RC filter branch on the dq axis, respectively.

[0065] To simplify the calculation, the relationship between voltage and current is transformed into the complex frequency domain. The relationship between the GSC output current and the grid voltage can be expressed as:

[0066] ;

[0067] The mathematical model of the GSC filter can be expressed as:

[0068] ;

[0069] in, , Capacitor voltages The d-axis and q-axis voltage components.

[0070] Therefore, we can conclude that:

[0071] ;

[0072] Among them, intermediate variables It can be represented as:

[0073] ;

[0074] Therefore, considering only the voltage variation at the receiving end of the grid, the current input to the grid can be obtained as:

[0075] .

[0076] Step S13: Determine the third current component output by the grid-side converter to the receiving-end grid based on the target parameters.

[0077] In this embodiment, before determining the third current component output by the grid-side converter to the receiving-end grid based on the target parameters, a second difference is first determined between the current component input by the grid-side converter to the receiving-end grid on the q-axis and the current component output by the grid-side converter to the resistor-capacitor filter branch on the q-axis. This second difference is determined as the current component output by the grid-side converter to the receiving-end grid after a grid fault occurs. Then, the target current is determined based on the target parameters using a preset target current determination formula. The preset target current determination formula is:

[0078] ;

[0079] in, The target current in the complex frequency domain; This is the transfer function of the d-axis current loop controller; This is the d-axis current command value; The current component output from the grid-side converter to the receiving-end grid on the q-axis under steady-state conditions before the fault occurs; This is the second current component in the complex frequency domain; The rotational angular velocity corresponding to the grid voltage frequency; For filtering inductors; s is the current component output from the grid-side converter to the receiving-end grid on the q-axis after a grid fault occurs in the complex frequency domain; s is a complex variable in the complex frequency domain; finally, the target current is subjected to an inverse Laplace transform to obtain the third current component output from the grid-side converter to the receiving-end grid.

[0080] Specifically, considering only the output voltage change of the grid-side converter, the voltage and current changes at the grid-side converter output can be expressed as follows (subscript 2 indicates the voltage and current changes at the grid-side converter output when only the output voltage change is considered):

[0081] ;

[0082] The output current of the GSC under the current state can be expressed as:

[0083] ;

[0084] Filter Inductor The relationship between voltage and current is:

[0085] ;

[0086] In the above formula, This represents the slip angular frequency (the difference between the frequency of the rotating magnetic field generated by the stator and the actual rotational frequency of the rotor in an asynchronous motor). The GSC output voltage is simultaneously affected by the parameters of the current loop proportional-integral regulator and the compensation circuit. Combined with the control method of direct-drive wind power, the GSC output voltage can be expressed as:

[0087] ;

[0088] In the formula, These are the proportional and integral coefficients of the d-axis current loop, respectively. These are the proportional and integral coefficients of the q-axis current loop, respectively.

[0089] According to the superposition theorem of sources These represent the tracking error of the d-axis (active) current, the tracking error of the q-axis (reactive) current, the sum of the d-axis transient currents used for decoupling calculations, and the sum of the q-axis transient currents used for decoupling calculations, respectively. They can be expressed as:

[0090] ;

[0091] In the formula: This is the d-axis current command value; This is the q-axis current command value.

[0092] Transforming to the complex frequency domain, the GSC output voltage can be expressed as:

[0093] ;

[0094] Therefore, the current in the current state can be expressed as:

[0095] ;

[0096] In the formula, the transfer function of the d-axis current loop controller is... .

[0097] Finally, for By performing the inverse Laplace transform, we can obtain the current-time domain solution in the current state. .

[0098] Step S14: Determine the active power output of the new energy system to the receiving-end grid through the first voltage component, the first current component, the second voltage component, the second current component, and the third current component.

[0099] In this embodiment, after calculating the first voltage component, the first current component, the second voltage component, the second current component, and the third current component, the active power output from the new energy system to the receiving-end grid is determined by a preset active power determination formula; the preset active power determination formula is:

[0100] ;

[0101] ;

[0102] in, The active power; The grid voltage component on the d-axis; The current component output from the grid-side converter to the receiving-end grid on the d-axis; This refers to the first voltage component; This refers to the first current component; This is the second voltage component; This is the second current component; This refers to the third current component.

[0103] Specifically, using the superposition theorem, the transient active power output to the grid from a direct-drive wind power system can be expressed as ( The grid voltage component on the q-axis is very small and can be ignored; therefore, in the formula, we can... The value is considered to be 0):

[0104] ;

[0105] Comparison of simulation and mathematical models of active power output of new energy systems under fault conditions, for example Figure 3 As shown.

[0106] in:

[0107] .

[0108] Simulation and mathematical models of d-axis voltage and d-axis current under fault conditions, for example... Figure 4 and Figure 5 As shown.

[0109] By dividing the transient response calculation of the renewable energy system under grid faults into three state components, a transient active power response model for renewable energy units considering different real-time grid voltage states and converter control parameters is established. This model can accurately calculate the transient active power response characteristics of the UHVDC receiving-end renewable energy system after common DC transmission faults. It can be used to analyze the characteristics of the receiving-end grid after common DC transmission faults, providing an effective solution to the new challenges posed by the increasing number and capacity of current HVDC transmission projects and the increasing grid connection of HVDC receiving-end renewable energy systems, which alters the steady-state and transient operating characteristics of the power system. This has significant theoretical and practical implications.

[0110] In summary, this application first obtains the equivalent circuit diagram of the grid-side converter when the new energy system is connected to the UHVDC transmission system at the receiving end, and determines the target parameters based on the equivalent circuit diagram. The target parameters include the phase voltage amplitude of the receiving-end grid, the phase current amplitude output to the receiving-end grid, the current component of the grid-side converter input to the receiving-end grid on the dq axis, the current component of the grid-side converter output to the resistor-capacitor filter branch on the dq axis, the current component of the grid-side converter output to the receiving-end grid on the q axis under steady state before the fault occurs, and the rotational angular velocity corresponding to the grid voltage frequency. The method involves determining the first voltage component of the grid-side converter and the first current component output to the receiving-end grid under steady-state conditions before the fault occurs, and determining the second voltage component of the grid-side converter and the second current component output to the receiving-end grid after the grid fault occurs based on the target parameters. The method also determines the third current component output by the grid-side converter to the receiving-end grid according to the target parameters. Finally, the active power output by the new energy system to the receiving-end grid is determined using the first voltage component, the first current component, the second voltage component, the second current component, and the third current component. This application employs the superposition theorem to divide the transient active power response calculation under receiving-end grid faults into three states: steady-state before the fault occurs, the state of grid voltage change after the fault occurs, and the state of grid-side converter output voltage change after the fault occurs. The active power is ultimately determined based on these three state components. This method can be applied to different grid voltage fault states and considers different converter control parameters to accurately calculate the active power output by the UHVDC receiving-end new energy system to the grid after common DC transmission faults.

[0111] See Figure 6 As shown in the figure, an embodiment of the present invention discloses a device for determining active power under fault conditions in the receiving-end grid of new energy access, comprising:

[0112] The parameter determination module 11 is used to obtain the equivalent circuit diagram of the grid-side converter when the new energy system is connected to the UHVDC transmission system at the receiving end, and to determine the target parameters based on the equivalent circuit diagram. The target parameters include the phase voltage amplitude of the receiving end grid, the phase current amplitude output to the receiving end grid, the current component of the grid-side converter input to the receiving end grid on the dq axis, the current component of the grid-side converter output to the resistor-capacitor filter branch on the dq axis, the current component of the grid-side converter output to the receiving end grid on the q axis under steady state before the fault occurs, the rotational angular velocity corresponding to the grid voltage frequency, and the filter inductance.

[0113] The first component determination module 12 is used to determine the first voltage component of the grid-side converter and the first current component output to the receiving-end grid under steady state before the fault occurs.

[0114] The second component determination module 13 is used to determine the second voltage component of the grid-side converter and the second current component output to the receiving-end grid after a grid fault occurs, based on the target parameters.

[0115] The third component determination module 14 is used to determine the third current component output from the grid-side converter to the receiving-end grid based on the target parameters.

[0116] The active power determination module 15 is used to determine the active power output from the new energy system to the receiving-end grid through the first voltage component, the first current component, the second voltage component, the second current component, and the third current component.

[0117] In some specific embodiments, the first component determination module 12 may specifically include:

[0118] The first voltage component determination unit is used to determine the phase voltage amplitude of the receiving-end power grid as the first voltage component of the grid-side converter under steady state before the fault occurs.

[0119] The first current component determination unit is used to determine the phase current amplitude output to the receiving-end grid as the first current component output by the grid-side converter to the receiving-end grid under steady-state conditions before the fault occurs.

[0120] In some specific embodiments, the second component determination module 13 may specifically include:

[0121] The second voltage component determination unit is used to determine the fitting function of the receiving-end grid voltage as the second voltage component of the grid-side converter after a grid fault occurs.

[0122] The first difference determination unit is used to determine the first difference between the current component input from the grid-side converter to the receiving-end grid on the d-axis and the current component output from the grid-side converter to the resistor-capacitor filter branch on the d-axis.

[0123] The second current component determination unit is used to determine the first difference as the second current component output by the grid-side converter to the receiving-end grid after a grid fault occurs.

[0124] In some specific embodiments, the apparatus may further include:

[0125] The second difference determination module is used to determine the second difference between the current component input from the grid-side converter to the receiving-end grid on the q-axis and the current component output from the grid-side converter to the resistor-capacitor filter branch on the q-axis.

[0126] The current component determination module is used to determine the second difference as the current component output by the grid-side converter to the receiving-end grid after a grid fault occurs.

[0127] In some specific embodiments, the third component determination module 14 may specifically include:

[0128] The target current determination unit is used to determine the target current based on the target parameters using a preset target current determination formula; the preset target current determination formula is:

[0129] ;

[0130] in, The target current in the complex frequency domain; This is the transfer function of the d-axis current loop controller; This is the d-axis current command value; The current component output from the grid-side converter to the receiving-end grid on the q-axis under steady-state conditions before the fault occurs; This is the second current component in the complex frequency domain; The rotational angular velocity corresponding to the grid voltage frequency; For filtering inductors; is the current component output from the grid-side converter to the receiving-end grid on the q-axis after a grid fault occurs in the complex frequency domain; s is a complex variable in the complex frequency domain;

[0131] The third current component determination unit is used to determine the third current component output from the grid-side converter to the receiving-end grid based on the target current.

[0132] In some specific embodiments, the third current component determination unit may specifically include:

[0133] The third current component determination subunit is used to perform an inverse Laplace transform on the target current to obtain the third current component output by the grid-side converter to the receiving-end grid.

[0134] In some specific embodiments, the active power determination module 15 may specifically include:

[0135] The active power determination unit is used to determine the active power output from the renewable energy system to the receiving-end power grid through a preset active power determination formula; the preset active power determination formula is:

[0136] ;

[0137] ;

[0138] in, The active power; The grid voltage component on the d-axis; The current component output from the grid-side converter to the receiving-end grid on the d-axis; This refers to the first voltage component; This refers to the first current component; This is the second voltage component; This is the second current component; This refers to the third current component.

[0139] Furthermore, embodiments of this application also disclose an electronic device, Figure 7 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.

[0140] Figure 7 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 method for determining active power under grid fault conditions for new energy access disclosed in any of the foregoing embodiments. Furthermore, the electronic device 20 in this embodiment may specifically be a computer.

[0141] 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.

[0142] 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.

[0143] 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 active power determination method under grid fault conditions for new energy access disclosed in any of the foregoing embodiments, the computer program 222 may further include computer programs capable of performing other specific tasks.

[0144] 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 determining active power under grid faults at the receiving end of renewable energy access. Specific steps of this method can be found in the corresponding content disclosed in the foregoing embodiments, and will not be repeated here.

[0145] 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.

[0146] 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.

[0147] 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.

[0148] 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.

[0149] 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 determining active power under grid fault conditions when new energy sources are connected to the receiving end of the grid, characterized in that, include: Obtain the equivalent circuit diagram of the grid-side converter when the new energy system is connected to the ultra-high voltage direct current transmission system at the receiving end, and determine the target parameters based on the equivalent circuit diagram; The target parameters include the phase voltage amplitude of the receiving-end grid, the phase current amplitude output to the receiving-end grid, the current component input from the grid-side converter to the receiving-end grid on the dq axis, the current component output from the grid-side converter to the resistor-capacitor filter branch on the dq axis, the current component output from the grid-side converter to the receiving-end grid on the q axis under steady state before the fault occurs, the rotational angular velocity corresponding to the grid voltage frequency, and the filter inductance. The first voltage component of the grid-side converter and the first current component output to the receiving-end grid under steady state before the fault occurs are determined, and the second voltage component of the grid-side converter and the second current component output to the receiving-end grid are determined based on the target parameters after the grid fault occurs. The third current component output from the grid-side converter to the receiving-end grid is determined based on the target parameters. The active power output from the new energy system to the receiving-end grid is determined by the first voltage component, the first current component, the second voltage component, the second current component, and the third current component.

2. The method for determining active power under grid fault conditions at the receiving end of new energy access according to claim 1, characterized in that, The determination of the first voltage component of the grid-side converter and the first current component output to the receiving-end grid under steady-state conditions before the fault occurs includes: The phase voltage amplitude of the receiving-end power grid is determined as the first voltage component of the grid-side converter under steady-state conditions before the fault occurs. The amplitude of the phase current output to the receiving-end grid is determined as the first current component output by the grid-side converter to the receiving-end grid under steady-state conditions before the fault occurs.

3. The method for determining active power under grid fault conditions at the receiving end of new energy access according to claim 1, characterized in that, The determination of the second voltage component of the grid-side converter and the second current component output to the receiving-end grid after a grid fault, based on the target parameters, includes: The fitting function of the receiving-end grid voltage is determined as the second voltage component of the grid-side converter after a grid fault occurs; Determine the first difference between the current component input from the grid-side converter to the receiving-end grid on the d-axis and the current component output from the grid-side converter to the resistor-capacitor filter branch on the d-axis; The first difference is determined as the second current component output by the grid-side converter to the receiving-end grid after a grid fault occurs.

4. The method for determining active power under grid fault conditions at the receiving end of new energy access according to claim 1, characterized in that, Before determining the third current component output from the grid-side converter to the receiving-end grid based on the target parameters, the method further includes: Determine a second difference between the current component input from the grid-side converter to the receiving-end grid on the q-axis and the current component output from the grid-side converter to the resistor-capacitor filter branch on the q-axis; The second difference is determined as the current component output by the grid-side converter to the receiving-end grid after a grid fault occurs.

5. The method for determining active power under grid fault conditions at the receiving end of new energy access according to claim 4, characterized in that, The step of determining the third current component output from the grid-side converter to the receiving-end grid based on the target parameters includes: The target current is determined based on the target parameters using a preset target current determination formula; the preset target current determination formula is: ； in, The target current in the complex frequency domain; This is the transfer function of the d-axis current loop controller; This is the d-axis current command value; The current component output from the grid-side converter to the receiving-end grid on the q-axis under steady-state conditions before the fault occurs; This is the second current component in the complex frequency domain; The rotational angular velocity corresponding to the grid voltage frequency; For filtering inductors; is the current component output from the grid-side converter to the receiving-end grid on the q-axis after a grid fault occurs in the complex frequency domain; s is a complex variable in the complex frequency domain; The third current component output by the grid-side converter to the receiving-end grid is determined based on the target current.

6. The method for determining active power under grid fault conditions at the receiving end of new energy access according to claim 5, characterized in that, The determination of the third current component output from the grid-side converter to the receiving-end grid based on the target current includes: The target current is subjected to an inverse Laplace transform to obtain the third current component output by the grid-side converter to the receiving-end grid.

7. The method for determining active power under grid fault conditions at the receiving end of a new energy source as described in any one of claims 1 to 6, characterized in that, The determination of the active power output from the renewable energy system to the receiving-end grid using the first voltage component, the first current component, the second voltage component, the second current component, and the third current component includes: The active power output from the new energy system to the receiving-end power grid is determined by a preset active power determination formula; the preset active power determination formula is as follows: ； ； in, The active power; The grid voltage component on the d-axis; The current component output from the grid-side converter to the receiving-end grid on the d-axis; This refers to the first voltage component; This refers to the first current component; This is the second voltage component; This is the second current component; This refers to the third current component.

8. A device for determining active power under grid fault conditions when new energy sources are connected to the receiving end of the grid, characterized in that, include: The parameter determination module is used to obtain the equivalent circuit diagram of the grid-side converter when the new energy system is connected to the receiving end of the UHVDC transmission system, and to determine the target parameters based on the equivalent circuit diagram. The target parameters include the phase voltage amplitude of the receiving-end grid, the phase current amplitude output to the receiving-end grid, the current component input from the grid-side converter to the receiving-end grid on the dq axis, the current component output from the grid-side converter to the resistor-capacitor filter branch on the dq axis, the current component output from the grid-side converter to the receiving-end grid on the q axis under steady state before the fault occurs, the rotational angular velocity corresponding to the grid voltage frequency, and the filter inductance. The first component determination module is used to determine the first voltage component of the grid-side converter and the first current component output to the receiving-end grid under steady-state conditions before the fault occurs. The second component determination module is used to determine the second voltage component of the grid-side converter and the second current component output to the receiving-end grid after a grid fault occurs, based on the target parameters. The third component determination module is used to determine the third current component output from the grid-side converter to the receiving-end grid based on the target parameters. The active power determination module is used to determine the active power output from the new energy system to the receiving-end grid through the first voltage component, the first current component, the second voltage component, the second current component, and the third current component.

9. An electronic device, characterized in that, include: Memory, used to store computer programs; A processor for executing a computer program to implement the method for determining active power under grid fault conditions for new energy access 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 method for determining active power under grid faults at the receiving end of new energy access as described in any one of claims 1 to 7.

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