Method and device for deducing influence of low-voltage penetration process of new energy equipment on voltage and medium

Abstract

The invention discloses a method for deducing the influence of a low-voltage penetration process of new energy equipment, equipment and a medium, and relates to the field of power systems. The method comprises the following steps: fitting frequency domain impedance in an s domain based on a pole fitting technology, and determining an expression of the frequency domain impedance in the s domain; calculating an injection current curve according to the new energy low-voltage crossing parameters based on a new energy low-voltage crossing current formula; calculating a current port voltage phasor curve according to the expression of the frequency domain impedance in the s domain and the injection current curve; and calculating a voltage deviation between the historical port voltage phasor curve and the current port voltage phasor curve based on a two-norm, and taking the current port voltage phasor curve as a voltage influence deduction result when the voltage deviation is smaller than a preset deviation threshold. Therefore, according to the electromagnetic transient and frequency characteristics of the net rack, the order of the system is reduced in a mechanism model extraction mode, the prediction efficiency is greatly improved, the accuracy and the efficiency are both considered, and the method is suitable for rapid scene stability analysis.

Description

Technical Field

[0001] The present invention relates to the field of power systems, and in particular, to a method, device, and medium for deducing the impact of the low voltage ride-through process of new energy equipment on voltage. Background Art

[0002] When analyzing the dynamic process of the power grid by electromechanical transient simulation, since the grid models such as transmission lines and transformers do not consider the electro-magnetic conversion process, there are problems with the accuracy and correctness of the voltage fluctuation results obtained by the simulation, which may lead to untrustworthy results and further affect the smooth progress of the transient security and stability analysis of the power grid.

[0003] At present, however, electromagnetic transient simulation has the problem of long time consumption when analyzing the dynamic process of large power grids. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to overcome the deficiencies in the prior art, and provide a method, device, and medium for deducing the impact of the low voltage ride-through process of new energy equipment on voltage, which is used to combine the electromagnetic transient and frequency characteristics of the grid framework, and at the same time reduce the order of the system by extracting the mechanism model. By extracting the poles and residues of the power grid network, a mechanism model is generated, and further, a rapid deduction of the impact of the low voltage ride-through process of energy equipment on voltage is realized.

[0005] The present invention provides the following technical solutions:

[0006] In a first aspect, the present invention proposes a method for deducing the impact of the low voltage ride-through process of new energy equipment on voltage, including:

[0007] Fitting the frequency domain impedance in the s domain based on the pole fitting technique to determine the expression of the frequency domain impedance in the s domain;

[0008] Based on the new energy low voltage ride-through current formula, calculate the injected current curve according to the new energy low voltage ride-through parameters;

[0009] Based on time domain convolution, calculate the current port voltage phasor curve according to the expression of the frequency domain impedance in the s domain and the injected current curve;

[0010] Calculate the voltage deviation between the historical port voltage phasor curve and the current port voltage phasor curve based on the two-norm. When the voltage deviation is less than the preset deviation threshold, use the current port voltage phasor curve as the voltage impact deduction result.

[0011] In an embodiment, the fitting the frequency domain impedance in the s domain based on the pole fitting technique to determine the expression of the frequency domain impedance in the s domain includes:

[0012] Construct a transfer function according to the frequency domain impedance corresponding to each sweep frequency sampling point in the s domain;

[0013] Solve the transfer function based on the least squares method to obtain multiple target poles and target residues;

[0014] Determine the expression of the frequency-domain impedance in the s-domain according to each of the target poles and each of the target residues.

[0015] In one embodiment, the expression of the frequency-domain impedance in the s-domain is formula (1):

[0016] In the formula, Z(s) is the frequency-domain impedance, N p is the number of the target poles, Z 0k is the residue, p k is the target pole, and d is a constant term.

[0017] In one embodiment, the solving of the transfer function based on the least squares method to obtain multiple target poles includes:

[0018] Solve the transfer function based on the least squares method to obtain multiple original poles;

[0019] Translate each of the original poles by a preset unit to obtain each of the target poles; the preset unit is -100πj.

[0020] In one embodiment, the new energy low-ride-through parameters include the d-axis low-ride-through parameter, the q-axis low-ride-through parameter, the low-ride-through recovery coefficient, and the voltage phase-locked loop measurement delay. Calculating the injected current curve according to the new energy low-ride-through current formula includes:

[0021] Calculate the d-axis current and q-axis current during the low-ride-through process and the recovery process according to the low-ride-through recovery coefficient, the d-axis low-ride-through parameter, and the q-axis low-ride-through parameter;

[0022] Calculate the injected current curve according to the voltage phase-locked loop measurement delay, the d-axis current and q-axis current during the low-ride-through process and the recovery process.

[0023] In one embodiment, the calculating of the injected current curve according to the voltage phase-locked loop measurement delay, the d-axis current and q-axis current during the low-ride-through process and the recovery process includes:

[0024] Calculate the injected current curve according to formula (2);

[0025] Formula (2):

[0026] In the formula, is the injected current curve, I dis the d-axis current, I q is the q-axis current, T θ is the measurement delay of the voltage phase-locked loop, θ V is the angle of the auxiliary frequency-domain voltage curve.

[0027] In one embodiment, the calculating the current port voltage phasor curve based on time-domain convolution according to the expression of the frequency-domain impedance in the s domain and the injected current curve includes:

[0028] Calculating the current port voltage phasor curve according to formula (3);

[0029] Formula (3):

[0030] In the formula, is the current port voltage phasor curve, and t is the current time.

[0031] In one embodiment, the calculating the voltage deviation between the historical port voltage phasor curve and the current port voltage phasor curve based on the second norm includes:

[0032] Calculating the voltage deviation according to formula (4); where formula (4): In the formula, ε is the voltage deviation, V old (t) is the historical port voltage phasor curve, V new (t) is the current port voltage phasor curve;

[0033] The method further includes:

[0034] If the voltage deviation is greater than or equal to the preset deviation threshold, then re-execute the step of calculating the injected current curve according to the new energy low-through current formula based on the new energy low-through parameters.

[0035] In a second aspect, the present invention provides a computer device, including a memory and a processor, where the memory stores a computer program, and when the computer program is executed by the processor, it implements the deduction method for the impact of the new energy device low-through process on voltage as described in the first aspect.

[0036] In a third aspect, the present invention provides a computer-readable storage medium, which stores a computer program, and when the computer program is executed by a processor, it implements the deduction method for the impact of the new energy device low-through process on voltage as described in the first aspect.

[0037] The deduction method, device and medium for the influence of the low voltage ride-through process of new energy equipment on voltage disclosed in the present invention fit the frequency domain impedance in the s domain based on the pole fitting technology to determine the expression of the frequency domain impedance in the s domain; calculate the injected current curve according to the new energy low voltage ride-through parameters based on the new energy low voltage ride-through current formula; calculate the current port voltage phasor curve based on the time domain convolution according to the expression of the frequency domain impedance in the s domain and the injected current curve; calculate the voltage deviation between the historical port voltage phasor curve and the current port voltage phasor curve based on the second norm, and when the voltage deviation is less than the preset deviation threshold, use the current port voltage phasor curve as the deduction result of the voltage influence. In this way, the electromagnetic transient and frequency characteristics of the grid are considered, and the order of the system is reduced by using the method of extracting the mechanism model, which greatly improves the prediction efficiency, thus taking into account both accuracy and efficiency and being applicable to fast scenario stability analysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions of the present invention, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as limiting the protection scope of the present invention. In each drawing, similar components are numbered similarly.

[0039] Figure 1 FIG. shows a schematic flowchart of the deduction method for the influence of the low voltage ride-through process of new energy equipment on voltage proposed in this embodiment;

[0040] Figure 2 FIG. shows another schematic flowchart of the deduction method for the influence of the low voltage ride-through process of new energy equipment on voltage proposed in this embodiment;

[0041] Figure 3 FIG. shows still another schematic flowchart of the deduction method for the influence of the low voltage ride-through process of new energy equipment on voltage proposed in this embodiment;

[0042] Figure 4 FIG. shows the first result schematic diagram of the fast deduction proposed in this embodiment;

[0043] Figure 5 FIG. shows the second result schematic diagram of the fast deduction proposed in this embodiment;

[0044] Figure 6 FIG. shows the first result schematic diagram of the electromagnetic transient simulation proposed in this embodiment;

[0045] Figure 7 FIG. shows the first result schematic diagram of the electromagnetic transient simulation proposed in this embodiment;

[0046] Figure 8Shows a schematic structural diagram of a deduction device for the impact of the low voltage ride-through process of new energy equipment proposed in this embodiment.

[0047] Explanation of the attached drawing reference numerals:

[0048] 800 - Deduction device for the impact of the low voltage ride-through process of new energy equipment; 801 - Fitting module; 802 - Calculation module; 803 - Convolution module; 804 - Determination module. Detailed implementation manners

[0049] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0050] Generally, the components of the embodiments of the present invention described and illustrated in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed present invention, but merely represents the selected embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0051] Hereinafter, the terms "including", "having" and their cognates that can be used in various embodiments of the present invention are only intended to represent specific features, numbers, steps, operations, elements, components or combinations of the foregoing items, and should not be construed as first excluding the existence of one or more other features, numbers, steps, operations, elements, components or combinations of the foregoing items or increasing the possibility of one or more features, numbers, steps, operations, elements, components or combinations of the foregoing items.

[0052] In addition, the terms "first", "second", "third", etc. are only used for distinguishing descriptions and cannot be understood as indicating or implying relative importance.

[0053] Unless otherwise defined, all terms (including technical terms and scientific terms) used here have the same meaning as those commonly understood by those of ordinary skill in the art to which various embodiments of the present invention belong. The terms (such as those defined in a commonly used dictionary) will be interpreted as having the same meaning as the contextual meaning in the relevant technical field and will not be interpreted as having an idealized meaning or being too formal, unless clearly defined in various embodiments of the present invention.

[0054] Embodiment 1

[0055] At present, the new energy equipment connected to the DC external transmission system is a common form in the sending-end power grid. However, when voltage fluctuations occur due to reasons such as commutation failures, it may trigger a large area of new energy to enter the low-ride-through state, thereby causing further voltage fluctuations in the power grid and even leading to a series of problems such as a large amount of new energy tripping off the grid. To address these problems, the existing main method is simulation calculation, lacking a "link" that connects the mechanisms and phenomena on the source, grid, and load sides.

[0056] The embodiment of the present disclosure provides a deduction method for the impact of the low-ride-through process of new energy equipment on voltage, which is used to combine the electromagnetic transient and frequency characteristics of the power grid framework, and at the same time adopts the method of extracting the mechanism model to reduce the order of the system. By extracting the poles and residues of the power grid network, a mechanism model is generated, and further rapid deduction of the impact of the low-ride-through process of energy equipment on voltage is realized.

[0057] Please refer to Figure 1 , a deduction method for the impact of the low-ride-through process of new energy equipment on voltage includes steps S101 to S104, and the following is a detailed description of each step.

[0058] Step S101: Fit the frequency-domain impedance in the s-domain based on the pole fitting technique to determine the expression of the frequency-domain impedance in the s-domain.

[0059] In this embodiment, by fitting the frequency-domain impedance in the s-domain based on the pole fitting technique, N p poles p k and residues Z 0k can be obtained, thereby forming the expression Z(s) of the frequency-domain impedance in the s-domain. That is, the expression of the frequency-domain impedance in the s-domain is formula (1): In the formula, d is a constant term. Among them, the frequency-domain impedance is a known condition.

[0060] This expression converts the impedance relationship in the time domain to the frequency domain through Laplace transform, so that the behavior of the circuit and system at different frequencies can be analyzed more conveniently.

[0061] Please refer to Figure 2 , in a specific embodiment, step S101 includes steps S1011 to S1013, and the following is a detailed description of each step.

[0062] Step S1011: Construct a transfer function according to the frequency-domain impedance corresponding to each swept-frequency sampling point in the s-domain.

[0063] In this embodiment, a transfer function is constructed according to the frequency-domain impedance corresponding to each swept-frequency sampling point in the s-domain. For example, In the formula, f(s) is Z(s), the number of sampling points M for swept frequency is greater than the number of residues N + 2, and generally the number of residues N is set to 20.

[0064] Step S1012, solve the transfer function based on the least squares method to obtain multiple target poles and target residues.

[0065] In this embodiment, the transfer function is solved based on the least squares method to obtain multiple target poles and target residues.

[0066] Specifically, introduce an additional function σ(s). Assume that the zero point of the σ(s) function is the pole a of f(s) n * , that is, the a for the next iteration n value, and the pole of σ(s) is the assumed initial pole a n .

[0067] Use the iterative method of pole fitting to solve the poles. During the iteration process, update a each time n .

[0068] Based on the pole characteristics of σ(s), write the σ(s) function as:

[0069] Based on the zero point characteristics of σ(s), the pole of σf(s) obtained by multiplying with f(s) is the initial pole a n , which can be written as:

[0070] Combining the two equations, calculate the undetermined coefficients using the least squares method. For this purpose, write the above equation as:

[0071] Thus, determine the parameter target poles through the least squares method. Where n = 1, 2,..., N. During the iteration process, the new can be obtained as the a for the next round of calculation n .

[0072] Furthermore, for the part of solving the target residues, the formula can be obtained:

[0073] Thus, obtain the target residues and constant terms based on the least squares method, that is, c1, c2, c3,..., c N , d, h.

[0074] It should be noted that after calculating the target poles, it is necessary to perform a convergence judgment on them. If the convergence condition is not met, re-execute the process of solving the target poles using the least squares method.

[0075] In a specific embodiment, step S1012 includes: solving the transfer function based on the least squares method to obtain a plurality of original poles; translating each of the original poles by a preset unit to obtain each target pole; the preset unit is -100πj.

[0076] In this embodiment, after solving for each pole through the least squares method, all current poles are original poles; further, each of the original poles is translated by a preset unit to obtain the corresponding target poles, thereby improving numerical stability. Among them, the preset unit can be -100πj.

[0077] Step S1013, determining the expression of the frequency-domain impedance in the s-domain according to each of the target poles and each of the target residues.

[0078] In this embodiment, determining the expression of the frequency-domain impedance in the s-domain according to each target pole and each target residue, that is

[0079] Step S102, based on the new energy low-ride-through current formula, calculating the injected current curve according to the new energy low-ride-through parameters.

[0080] In this embodiment, obtaining the new energy low-ride-through parameters, including reactive power, active power parameters, etc., and further calculating the injected current curve according to the new energy low-ride-through current formula, which is used to describe the trajectory of the active current and reactive current output by the new energy device over time during the grid voltage dip.

[0081] Please refer to Figure 3 , in a specific embodiment, the new energy low-ride-through parameters include d-axis low-ride-through parameters, q-axis low-ride-through parameters, low-ride-through recovery coefficient, and voltage phase-locked loop measurement delay. Step S102 includes steps S1021 to S1022, and the following details each step.

[0082] Step S1021, calculating the d-axis current and q-axis current during the low-ride-through process and the recovery process according to the low-ride-through recovery coefficient, the d-axis low-ride-through parameters, and the q-axis low-ride-through parameters.

[0083] In this embodiment, calculating the d-axis current and q-axis current during the low-ride-through process and the recovery process according to the low-ride-through recovery coefficient, the d-axis low-ride-through parameters, and the q-axis low-ride-through parameters.

[0084] The d-axis low-ride-through parameters include the d-axis current coefficient K d , the d-axis voltage coefficient K dv , the d-axis low-ride-through current constant I dset , and the q-axis low-ride-through parameters include the q-axis current coefficient K q , the q-axis voltage coefficient K qv , the q-axis low-ride-through current constant I qset .

[0085] Specifically, for the low-through process, according to the d-axis current coefficient K d , the d-axis voltage coefficient K dv , the d-axis low-through current constant I dset , the steady-state voltage amplitude V0, and the voltage value V at the current time, calculate the d-axis current, that is, the d-axis current I d = I dset + K d I d0 + K dv (V0 - V); According to the q-axis current coefficient K q , the q-axis voltage coefficient K qv , the q-axis low-through current constant I qset , the steady-state voltage amplitude V0, and the voltage value V at the current time, calculate the d-axis current, that is, the q-axis current I q = I qset + K q I q0 + Kqv(V 0 - V).

[0086] For the recovery process, according to the d-axis initial current I d0 , the low-through recovery coefficient c, the d-axis current coefficient K d , the d-axis voltage coefficient K dv , the d-axis low-through current constant I dset , the low-through end time t1 and the current time t, calculate the d-axis current, that is, the d-axis current I d = I dset + K d I d0 + cI d0 (t - t1); According to the q-axis initial current I q0 , the low-through recovery coefficient c, the q-axis current coefficient K q , the q-axis voltage coefficient K qv , the q-axis low-through current constant I qset , the low-through end time t1 and the current time t, calculate the q-axis current, that is, the q-axis current I q = I qset + K q I q0 + cI q0 (t - t1).

[0087] Among them, the low-through end time t1 is generally set to 0.1 s.

[0088] Step S1022, calculate the injection current curve according to the voltage phase-locked loop measurement delay, the d-axis current and the q-axis current in the low-through process and the recovery process.

[0089] In this embodiment, according to the voltage phase-locked loop to measure the delay time, the d-axis current and q-axis current during the low-ride-through process and the recovery process are used to calculate the injected current curve. Combining the dq-axis current with the PLL dynamic delay compensation, the injected current curve in the auxiliary frequency domain that meets the grid synchronization requirements is accurately generated.

[0090] Specifically, the injected current curve is calculated according to formula (2) Formula (2): In the formula, θ V is the phase angle curve of the auxiliary frequency domain voltage.

[0091] Step S103, based on time-domain convolution, calculate the current port voltage phasor curve according to the expression of the frequency-domain impedance in the s domain and the injected current curve.

[0092] In this embodiment, the injected current curve and the expression Z(s) of the frequency-domain impedance in the s domain are used to solve the current port voltage phasor curve through time-domain convolution Solving the port voltage through the time-domain convolution of the injected current curve and the frequency-domain impedance can accurately predict the voltage behavior of the power grid under dynamic current disturbances.

[0093] Specifically, the current port voltage phasor curve is calculated according to formula (3) Formula (3): Where, * represents convolution.

[0094] Step S104, calculate the voltage deviation between the historical port voltage phasor curve and the current port voltage phasor curve based on the second norm. When the voltage deviation is less than the preset deviation threshold, use the current port voltage phasor curve as the voltage impact deduction result.

[0095] In this embodiment, calculating the voltage deviation between the historical port voltage phasor curve and the current port voltage phasor curve based on the second norm can effectively quantify the difference between the two curves. The voltage deviation ε calculation formula is: V old (t) is the historical port voltage phasor curve, and ||·||2 represents the second norm.

[0096] Compare the calculated voltage deviation with the preset deviation threshold. If the voltage deviation is less than the preset deviation threshold, use the current port voltage phasor curve as the voltage impact deduction result. The preset deviation threshold is generally 1%.

[0097] In a specific embodiment, the method further includes: if the voltage deviation is greater than or equal to the preset deviation threshold, re-execute the step of calculating the injected current curve according to the new energy low-ride-through current formula and the new energy low-ride-through parameters.

[0098] In this embodiment, if the voltage deviation is greater than or equal to the preset deviation threshold, it can be known that the deviation is large at this time, and step S102 is re-executed.

[0099] Exemplarily, please refer to Figure 4 , Figure 5 , Figure 6 , Figure 7 , it can be known that Figure 4 the active power processing curve estimate-P of the new energy port deduced by the method of this embodiment is consistent with the trend of the active power processing curve P:0 of the new energy port in the electromagnetic transient simulation in Figure 6 , Figure 4 the reactive power processing curve estimate-Q of the new energy port deduced by the method of this embodiment is consistent with the trend of the reactive power processing curve Q:0 of the new energy port in the electromagnetic transient simulation in Figure 6 , and Figure 5 the voltage magnitude orientation trend of bus-G1, bus-22, bus-81, and bus-61 on an entire circuit deduced by the method of this embodiment is consistent with the voltage magnitude orientation trend of bus-G1, bus-22, bus-81, and bus-61 on an entire circuit in the electromagnetic transient simulation in Figure 7 . Therefore, the deduction method for the impact of the new energy equipment low voltage ride-through process on voltage proposed in this embodiment can effectively analyze the impact of the new energy equipment low voltage ride-through process on voltage.

[0100] The deduction method, device, and medium for the impact of the new energy equipment low voltage ride-through process on voltage proposed in this embodiment fit the frequency domain impedance in the s domain based on the pole fitting technology to determine the expression of the frequency domain impedance in the s domain; calculate the injected current curve according to the new energy low voltage ride-through parameters based on the new energy low voltage ride-through current formula; calculate the current port voltage phasor curve based on the time domain convolution according to the expression of the frequency domain impedance in the s domain and the injected current curve; calculate the voltage deviation between the historical port voltage phasor curve and the current port voltage phasor curve based on the second norm, and when the voltage deviation is less than the preset deviation threshold, use the current port voltage phasor curve as the voltage impact deduction result. In this way, the electromagnetic transient and frequency characteristics of the grid are considered, and at the same time, the system order is reduced by extracting the mechanism model, greatly accelerating the prediction efficiency, so as to balance accuracy and efficiency and be applicable to fast scenario stability analysis.

[0101] Embodiment 2

[0102] In addition, an embodiment of the present disclosure provides a deduction device 800 for the impact of the new energy equipment low voltage ride-through process on voltage. Please refer to Figure 8 , including:

[0103] ​​The fitting module 801 is used to fit the frequency-domain impedance in the s-domain based on the pole fitting technique and determine the expression of the frequency-domain impedance in the s-domain.

[0104] The calculation module 802 is used to calculate the injected current curve based on the new energy low-ride-through current formula and the new energy low-ride-through parameters.

[0105] The convolution module 803 is used to calculate the current port voltage phasor curve based on time-domain convolution according to the expression of the frequency-domain impedance in the s-domain and the injected current curve.

[0106] The determination module 804 is used to calculate the voltage deviation between the historical port voltage phasor curve and the current port voltage phasor curve based on the two-norm. When the voltage deviation is less than the preset deviation threshold, the current port voltage phasor curve is used as the voltage influence deduction result.

[0107] Optionally, the fitting module 801 is further used to construct a transfer function according to the frequency-domain impedance corresponding to each sweep frequency sampling point in the s-domain; solve the transfer function based on the least squares method to obtain multiple target poles and target residues; determine the expression of the frequency-domain impedance in the s-domain according to each target pole and each target residue.

[0108] Optionally, the expression of the frequency-domain impedance in the s-domain is formula (1): In the formula, Z(s) is the frequency-domain impedance, N p is the number of the target poles, Z 0k is the residue, p k is the target pole, and d is the constant term.

[0109] Optionally, the fitting module 801 is further used to solve the transfer function based on the least squares method to obtain multiple original poles; translate each original pole by a preset unit to obtain each target pole; the preset unit is -100πj.

[0110] Optionally, the new energy low-ride-through parameters include the d-axis low-ride-through parameter, the q-axis low-ride-through parameter, the low-ride-through recovery coefficient, and the voltage phase-locked loop measurement delay. The calculation module 802 is further used to calculate the d-axis current and q-axis current during the low-ride-through process and the recovery process according to the low-ride-through recovery coefficient, the d-axis low-ride-through parameter, and the q-axis low-ride-through parameter; calculate the injected current curve according to the voltage phase-locked loop measurement delay, the d-axis current and q-axis current during the low-ride-through process and the recovery process.

[0111] Optionally, the calculation module 802 is further used to calculate the injected current curve according to formula (2); formula (2): In the formula, is the injected current curve, Id is the d-axis current, I q is the q-axis current, T θ is the measurement delay of the voltage phase-locked loop, θ x is the angle of the auxiliary frequency-domain voltage curve.

[0112] Optionally, the convolution module 803 is further configured to calculate the current port voltage phasor curve according to formula (3); formula (3): In the formula, is the current port voltage phasor curve, and t is the current time.

[0113] Optionally, the determination module 804 is further configured to calculate the voltage deviation according to formula (4); wherein, formula (4): In the formula, ε is the voltage deviation, V old (t) is the historical port voltage phasor curve, V new (t) is the current port voltage phasor curve;

[0114] The device further includes a processing module, configured to re-execute the step of calculating the injection current curve according to the new energy low-through current formula based on the new energy low-through parameters if the voltage deviation is greater than or equal to the preset deviation threshold.

[0115] The device provided by the embodiments of the present disclosure can execute the steps of the deduction method for the influence of the new energy equipment low-through process on the voltage provided in Embodiment 1. To avoid repetition, it will not be elaborated here.

[0116] The deduction device for the influence of the new energy equipment low-through process on the voltage proposed in this embodiment fits the frequency-domain impedance in the s domain based on the pole fitting technology to determine the expression of the frequency-domain impedance in the s domain; calculates the injection current curve according to the new energy low-through current formula based on the new energy low-through parameters; calculates the current port voltage phasor curve based on time-domain convolution according to the expression of the frequency-domain impedance in the s domain and the injection current curve; calculates the voltage deviation between the historical port voltage phasor curve and the current port voltage phasor curve based on the second norm, and when the voltage deviation is less than the preset deviation threshold, uses the current port voltage phasor curve as the deduction result of the voltage influence. In this way, the electromagnetic transient and frequency characteristics of the power grid are considered, and at the same time, the order of the system is reduced by extracting the mechanism model, which greatly improves the prediction efficiency, thus taking into account both accuracy and efficiency and being applicable to fast scenario stability analysis.

[0117] Embodiment 3

[0118] In addition, an embodiment of the present disclosure provides a computer device, including a memory and a processor. The memory stores a computer program, and when the computer program is executed by the processor, it implements the method for deducing the influence of the low voltage ride-through process of the new energy device on voltage described in Embodiment 1.

[0119] The device provided by the embodiment of the present disclosure can execute the steps of the method for deducing the influence of the low voltage ride-through process of the new energy device on voltage provided in Embodiment 1. To avoid repetition, details are not described herein again.

[0120] Embodiment 4

[0121] An embodiment of the present disclosure provides a computer-readable storage medium, which stores a computer program, and when the computer program is executed by a processor, it implements the method for deducing the influence of the low voltage ride-through process of the new energy device on voltage described in Embodiment 1 of the present disclosure.

[0122] In this embodiment, the computer-readable storage medium can be a read-only memory (ROM), a random access memory (RAM), a magnetic disk, an optical disk, or the like.

[0123] The computer-readable storage medium provided by this embodiment can implement the method for deducing the influence of the low voltage ride-through process of the new energy device on voltage provided in Embodiment 1. To avoid repetition, details are not described herein again.

[0124] In all the examples shown and described here, any specific value should be construed as merely exemplary, not as a limitation. Therefore, other examples of the exemplary embodiments may have different values.

[0125] It should be noted that like reference numerals and letters denote like items in the following figures. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0126] The above-described embodiments merely represent several implementation manners of the present invention. The description thereof is relatively specific and detailed, but it should not be construed as a limitation to the scope of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can be made, and these all belong to the protection scope of the present invention.

Claims

1. A deduction method for the influence of a low voltage ride-through process of a new energy device on voltage, characterized in that Including: Fitting the frequency-domain impedance in the s-domain based on the pole-fitting technique to determine the expression of the frequency-domain impedance in the s-domain; Calculating the injected current curve based on the new energy low-ride-through current formula and the new energy low-ride-through parameters; Calculating the current port voltage phasor curve based on time-domain convolution according to the expression of the frequency-domain impedance in the s-domain and the injected current curve; Calculating the voltage deviation between the historical port voltage phasor curve and the current port voltage phasor curve based on the second norm. When the voltage deviation is less than the preset deviation threshold, taking the current port voltage phasor curve as the voltage influence deduction result.

2. The deduction method for the influence of the low voltage ride-through process of new energy equipment on voltage according to claim 1, characterized in that, The step of fitting the frequency-domain impedance in the s-domain based on the pole-fitting technique to determine the expression of the frequency-domain impedance in the s-domain includes: Constructing a transfer function according to the frequency-domain impedance corresponding to each swept-frequency sampling point in the s-domain; Solving the transfer function based on the least squares method to obtain multiple target poles and target residues; Determining the expression of the frequency-domain impedance in the s-domain according to each of the target poles and each of the target residues.

3. The deduction method for the influence of the low voltage ride-through process of new energy equipment on voltage according to claim 2, characterized in that, The expression of the frequency-domain impedance in the s-domain is given by Equation (1): wherein, Z(s) is the frequency-domain impedance, N p is the number of the target poles, Z 0k is the residue, p k is the target pole, and d is a constant term.

4. The deduction method for the influence of the low voltage ride-through process of new energy equipment on voltage according to claim 2, characterized in that The step of solving the transfer function based on the least squares method to obtain multiple target poles includes: Solving the transfer function based on the least squares method to obtain multiple original poles; Translating each of the original poles by a preset unit to obtain each of the target poles; the preset unit is -100πj.

5. The deduction method for the influence of the low voltage ride-through process of new energy equipment on voltage according to claim 1, characterized in that, The new energy low-ride-through parameters include the d-axis low-ride-through parameter, the q-axis low-ride-through parameter, the low-ride-through recovery coefficient, and the voltage phase-locked loop measurement delay. The step of calculating the injected current curve based on the new energy low-ride-through current formula and the new energy low-ride-through parameters includes: Calculating the d-axis current and q-axis current during the low-ride-through process and the recovery process according to the low-ride-through recovery coefficient, the d-axis low-ride-through parameter, and the q-axis low-ride-through parameter; Calculating the injected current curve according to the voltage phase-locked loop measurement delay, the d-axis current and q-axis current during the low-ride-through process and the recovery process.

6. The deduction method for the influence of the low voltage ride-through process of new energy equipment on voltage according to claim 5, characterized in that, The step of calculating the injected current curve according to the voltage phase-locked loop measurement delay, the d-axis current and q-axis current during the low-ride-through process and the recovery process includes: Calculating the injected current curve according to formula (2); Formula (2): In the formula, is the injection current curve, I d is the d-axis current, I q is the q-axis current, T θ is the measurement delay of the voltage phase-locked loop, θ V is the angle of the auxiliary frequency-domain voltage curve.

7. The deduction method for the influence of the low voltage ride-through process of new energy equipment on voltage according to claim 3, characterized in that, The step of calculating the current port voltage phasor curve based on time-domain convolution according to the expression of the frequency-domain impedance in the s-domain and the injected current curve includes: Calculating the current port voltage phasor curve according to formula (3); Formula (3): In the formula, is the phasor curve of the current port voltage, and t is the current time.

8. The method for deducing the influence of the low voltage ride-through process of a new energy device on voltage according to claim 1, characterized in that The step of calculating the voltage deviation between the historical port voltage phasor curve and the current port voltage phasor curve based on the second norm includes: Calculate the voltage deviation according to formula (4); wherein, formula (4): In the formula, ε is the voltage deviation, V old (t) is the historical port voltage phasor curve, V new (t) is the current port voltage phasor curve; The method further includes: If the voltage deviation is greater than or equal to the preset deviation threshold, re-executing the step of calculating the injected current curve based on the new energy low-ride-through current formula and the new energy low-ride-through parameters.

9. A computer device, characterized in that, Including a memory and a processor, the memory stores a computer program, and when the computer program is executed by the processor, it implements the method for deducing the influence of the new energy device's low-ride-through process on voltage as described in any one of claims 1 to 8.

10. A computer-readable storage medium, characterized in that, It stores a computer program which, when executed by a processor, implements the deduction method for the impact of the low voltage ride-through process of the new energy device on voltage as described in any one of claims 1 to 8.

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