CN109818346A - Method and device for transient calculation of closed loop current based on frequency domain analysis - Google Patents

Abstract

The invention discloses a kind of Alloy White Iron Method for Transient Calculation and device based on frequency-domain analysis, wherein method includes: to obtain N²One group of identical initial public pole in a element；Vector fitting is carried out one by one to each element of FDNE matrix according to initial public pole, pole and its number to guarantee each element are identical；If pole is not converged, one group of newly public pole is obtained after vector fitting；Vector fitting is re-started using new public pole as initial public pole, until the difference of initial public pole and new public pole in predetermined threshold level, obtains the FDNE matrix with public pole；Solve cyclization transient current.This method can realize Alloy White Iron Transient calculation by the rapid vector fitting process based on frequency-domain analysis, improve and calculate accuracy and speed, and further increase power supply reliability, ensure the normal production and living of user.

Description

Method and device for transient calculation of closed loop current based on frequency domain analysis

technical field

The invention relates to the technical field of closed loop current transient calculation in a power system, in particular to a closed loop current transient calculation method and device based on frequency domain analysis.

Background technique

The loop closure transient current is the main factor for the success of the loop closure. Therefore, accurate and fast calculation of the loop closure transient current is related to the success of the loop closure, and is of great significance to ensure the normal production and life of users and improve the reliability of power supply.

In related technologies, some models use a simplified Thevenin equivalent circuit to calculate the closed loop current, but the actuarial accuracy is insufficient; although the closed loop current is calculated through the electromagnetic transient of the whole network, although the accuracy is satisfactory, it cannot be realized due to the large amount of calculation; according to experience To judge whether the loop can be closed, it can only be aimed at a specific network, which is not universal and representative, and needs to be solved urgently.

SUMMARY OF THE INVENTION

The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

Therefore, an object of the present invention is to propose a closed loop current transient calculation method based on frequency domain analysis, which can improve the accuracy and speed of calculation, further improve the reliability of power supply, and ensure the normal production and life of users.

Another object of the present invention is to provide a closed loop current transient calculation device based on frequency domain analysis.

In order to achieve the above object, an embodiment of the present invention proposes a closed loop current transient calculation method based on frequency domain analysis, including the following steps: obtaining a set of identical initial common poles in N ² elements; The common poles perform vector fitting on each element of the FDNE matrix one by one to ensure that the poles and the number of each element are the same; if the poles do not converge, a new set of common poles will be obtained after the vector fitting; The new common pole is used as the initial common pole to perform vector fitting again until the difference between the initial common pole and the new common pole is within a preset threshold value, and an FDNE matrix with a common pole is obtained; transient current.

The method for transient calculation of closed loop current based on frequency domain analysis according to the embodiment of the present invention and the method for transient calculation of closed loop current based on frequency domain analysis proposed in the embodiment of the present invention can be implemented by a fast vector fitting method based on frequency domain analysis. The closed-loop current transient calculation overcomes the shortcomings that the accuracy and speed cannot be fully satisfied in the closed-loop current transient calculation, effectively improves the calculation accuracy and speed, and further improves the reliability of power supply to ensure the normal production and life of users.

In addition, the closed loop current transient calculation method based on frequency domain analysis according to the above-mentioned embodiment of the present invention may also have the following additional technical features:

Further, in an embodiment of the present invention, the obtaining a set of identical initial common poles in the N ² elements further includes: if the number of sampling points is N ₀ , obtaining N N×N-dimensional sampling values matrix; add N ² element values in each sample value matrix in the N N×N-dimensional sample value matrices in turn to obtain N ₀ × 1 sample value vectors; perform vectorization on the sample value vectors Fitting to obtain a rational function; obtaining the pole of the rational function to obtain the initial common pole.

Further, in an embodiment of the present invention, each element of the FDNE matrix with a common pole is a frequency domain function:

Among them, the pole a _i and the residue c _i are real numbers or complex conjugate pairs, d and h are real numbers, n is the number of poles, and s is the complex frequency.

Further, in an embodiment of the present invention, the solution for the closed loop transient current further includes:

Establish FDNE (Frequency Dependent Network Equivalent, based on the equivalent model of frequency domain analysis technology to solve the closed loop transient current, where the relationship between the voltage and current of the transmission network can be expressed as:

Among them, I _B is the current of the boundary bus, I _E is the current of the other buses except the boundary bus, U _E is the voltage of the other buses except the boundary bus, U _B is the voltage of the boundary bus, f is the frequency, the subscript B is the boundary bus, the lower Mark E is other busbars in the transmission network;

To get the FDNE matrix and Norton equivalent current after shrinking to the boundary, and the Norton equivalent current is:

Among them, f ₀ is the fundamental frequency.

Further, in an embodiment of the present invention, the method further includes: converting the Norton-equivalent current into a three-phase current source; and performing differential on the three-phase current source through an implicit trapezoidal method.

In order to achieve the above object, another embodiment of the present invention provides a closed loop current transient calculation device based on frequency domain analysis, including: an acquisition module for acquiring a set of identical initial common poles in N ² elements; The first fitting module is used to perform vector fitting on each element of the FDNE matrix one by one according to the initial common pole, so as to ensure that the pole and the number of each element are the same; the judgment module is used if the pole is not Convergence, then a set of new common poles are obtained after the vector fitting is over; the second fitting module is used to re-fit the vector using the new common poles as the initial common poles until the initial common poles are the same as the all Assuming that the difference between the new common poles is within the preset threshold value, an FDNE matrix with common poles is obtained; the calculation module solves the closed loop transient current.

The closed loop current transient calculation device based on frequency domain analysis according to the embodiment of the present invention, and the closed loop current transient calculation method based on frequency domain analysis proposed in the embodiment of the present invention, can be realized by the fast vector fitting method based on frequency domain analysis The closed-loop current transient calculation overcomes the shortcomings that the accuracy and speed cannot be fully satisfied in the closed-loop current transient calculation, effectively improves the calculation accuracy and speed, and further improves the reliability of power supply to ensure the normal production and life of users.

In addition, the closed loop current transient calculation device based on frequency domain analysis according to the above-mentioned embodiment of the present invention may also have the following additional technical features:

Further, in an embodiment of the present invention, the obtaining module further includes: a first obtaining unit, configured to obtain N N×N-dimensional sampling value matrices if the number of sampling points is N ₀ ; a calculating unit , which is used to sequentially add N ² element values in each sampling value matrix in the N N×N-dimensional sampling value matrices to obtain an N ₀ × 1 sampling value vector; the fitting unit is used for pairing The sampling value vector is subjected to vector fitting to obtain a rational function; the second obtaining unit is used to obtain the pole of the rational function to obtain the initial common pole.

Further, in an embodiment of the present invention, each element of the FDNE matrix with a common pole is a frequency domain function:

Among them, the pole a _i and the residue c _i are real numbers or complex conjugate pairs, d and h are real numbers, n is the number of poles, and s is the complex frequency.

Further, in an embodiment of the present invention, the calculation module further includes: a establishing unit for establishing an FDNE equivalent model to solve the closed loop transient current, wherein the relationship between the voltage and current of the transmission network can be expressed as :

Among them, I _B is the current of the boundary bus, I _E is the current of the other buses except the boundary bus, U _E is the voltage of the other buses except the boundary bus, U _B is the voltage of the boundary bus, f is the frequency, the subscript B is the boundary bus, the lower Mark E is other busbars in the transmission network;

To get the FDNE matrix and Norton equivalent current after shrinking to the boundary, and the Norton equivalent current is:

Among them, f ₀ is the fundamental frequency.

Further, in an embodiment of the present invention, the method further includes: converting the Norton-equivalent current into a three-phase current source; and performing differential on the three-phase current source through an implicit trapezoidal method.

Additional aspects and advantages of the present invention will be set forth, in part, from the following description, and in part will be apparent from the following description, or may be learned by practice of the invention.

Description of drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of embodiments taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a flowchart of a method for transient calculation of closed loop current based on frequency domain analysis according to an embodiment of the present invention;

2 is a flowchart of a method for transient calculation of closed loop current based on frequency domain analysis according to an embodiment of the present invention;

3 is a schematic diagram of an equivalent model based on FDNE according to an embodiment of the present invention;

FIG. 4 is a schematic structural diagram of a closed loop current transient calculation device based on frequency domain analysis according to an embodiment of the present invention.

Detailed ways

The following describes in detail the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary, and are intended to explain the present invention and should not be construed as limiting the present invention.

The method and device for calculating the closed loop current transient based on frequency domain analysis proposed according to the embodiments of the present invention will be described below with reference to the accompanying drawings. calculation method.

FIG. 1 is a flowchart of a method for transient calculation of closed loop current based on frequency domain analysis according to an embodiment of the present invention.

As shown in Figure 1, the closed loop current transient calculation method based on frequency domain analysis includes the following steps:

In step S101, a set of identical initial common poles in N ² elements is obtained.

Further, in an embodiment of the present invention, obtaining a set of identical initial common poles in N ² elements further includes: if the number of sampling points is N ₀ , obtaining N N×N-dimensional sampling value matrices; Add the ^N2 element values in each sampled value matrix of N N×N-dimensional sampled value matrices in turn to obtain an _N0 ×1 sampled value vector; perform vector fitting on the sampled value vector to obtain a rational function ; Get the poles of the rational function and get the initial common pole.

It can be understood that, with reference to FIG. 1 and FIG. 2 , in this embodiment of the present invention, a set of the same initial common poles may be obtained for the N ² elements first. If the number of sampling points is N ₀ , N N×N-dimensional sampling value matrices can be obtained, and the N ² element values in each sampling value matrix can be added in turn. For N ₀ sampling value matrices, an N A "sampled value vector" of ₀ × 1, and by performing vector fitting on this "sampled value vector", a rational function can be obtained, and the pole of this rational function is set as the initial common pole of the original FDNE matrix.

In step S102, vector fitting is performed on each element of the FDNE matrix one by one according to the initial common pole, so as to ensure that the poles and the number of each element are the same.

It can be understood that, with reference to FIG. 1 and FIG. 2, based on the initial common pole in step S101, vector fitting is performed on each element in the FDNE matrix one by one to ensure that the poles and the number of each element of the FDNE matrix are the same.

In step S103, if the poles do not converge, a new set of common poles are obtained after the vector fitting is completed.

In step S104, the new common pole is used as the initial common pole to perform vector fitting again until the difference between the initial common pole and the new common pole is within a preset threshold value, and an FDNE matrix with common poles is obtained.

It can be understood that, with reference to Fig. 1 and Fig. 2, it can be seen from the vector fitting method that when the poles are not converged, a new set of poles can be obtained after the vector fitting method is completed, and the new set of poles can be re-used as the parameters in step S102. Initial common pole, and re-fit the vector until the difference between the initial common node and the new pole after the algorithm ends is within a certain threshold. Generally, iterate 3-4 times to converge and obtain the FDNE with the common pole. matrix.

It can be understood that, in the process of vector fitting in this embodiment of the present invention, the following practical processing methods can be adopted:

First, in the actual calculation process, h can generally be set to 0. For the actual network, at an infinite frequency, the node admittance of the actual network cannot be infinite.

Therefore, in order to ensure that the fitted rational function exhibits accurate frequency characteristics at both the fundamental frequency and the broadband frequency, relatively large weights are generally set to the sampled values at the fundamental frequency and the broadband frequency during fitting.

The fast vector fitting method can ensure that the poles of each element of Y(s) are the same, so only the residue term and the constant term are different, then the N×N-dimensional FDNE matrix Y(s) can be expressed as:

Write the above matrix in the form of a transfer function:

Y(s)=C(sE-A) ^-1 B+D,

where E is the identity matrix, and its dimension is the same as that of matrix A.

A=diag(A ₁ . . . A _k . . A _N ),

B=diag(B ₁ ... B _k ... B _N ),

B _k = [(1 1 … 1) _(1×n) ] ^T ,

k,m=1,2,...,N.

In step S105, the closed loop transient current is solved.

Further, in an embodiment of the present invention, solving the closed loop transient current further includes: establishing an FDNE equivalent model to solve the closed loop transient current, wherein the relationship between the voltage and current of the transmission network can be expressed as:

Among them, I _B is the current of the boundary bus, I _E is the current of the other buses except the boundary bus, U _E is the voltage of the other buses except the boundary bus, U _B is the voltage of the boundary bus, f is the frequency, the subscript B is the boundary bus, the lower Mark E is other busbars in the transmission network;

To get the FDNE matrix and Norton equivalent current after shrinking to the boundary, and the Norton equivalent current is:

Among them, f ₀ is the fundamental frequency.

It can be understood that the FDNE equivalent model is shown in FIG. 3 , and the embodiment of the present invention can use the fast vector fitting method to solve the closed loop transient current. In the embodiment of the present invention, FDNE is considered, so the relationship between the voltage and current of the transmission network can be expressed as:

Among them, the subscript B refers to the boundary bus, and the subscript E refers to the other bus in the transmission network. Gaussian elimination is performed on the formula and UE is eliminated to obtain the _FDNE matrix and Norton's equivalent current after shrinking to the boundary. Due to the long distance between the clutch and loop points of the transmission network with the voltage level of 220kV, the Norton equivalent current can only consider the fundamental frequency component, so the Norton equivalent formula is:

where f ₀ is the fundamental frequency.

Further, in an embodiment of the present invention, the method of the embodiment of the present invention further includes: converting the Norton equivalent current into a three-phase current source; and performing differential on the three-phase current source through an implicit trapezoidal method.

It should be noted that, in order to make the above Norton equivalent results applicable to the closed loop current transient calculation, two steps are required: first, the Norton equivalent current is converted into a three-phase current source; second, the implicit trapezoidal method is used to differentiate. Since the poles and the number of each element in the FDNE matrix in the embodiment of the present invention are the same, the difference can be unified. And according to the simulation results, the closed loop transient current peak value and transient characteristics are calculated.

Further, in an embodiment of the present invention, each element of the FDNE matrix with a common pole is a frequency domain function:

Among them, the pole a _i and the residue c _i are real numbers or complex conjugate pairs, d and h are real numbers, n is the number of poles, and s is the complex frequency.

It can be understood that the essence of FDNE is a nodal admittance matrix which is a function of frequency, which can represent the nodal admittance matrix in the case of frequency variation. Therefore, an N×N-dimensional FDNE can be expressed as a frequency-domain matrix:

The vector fitting method fits the sampled values of each element of the FDNE matrix at a series of frequencies into a continuous rational function, and each element in the FDNE matrix obtained by the vector fitting method can be expressed as a frequency domain function :

Among them, the pole a _i and the residue c _i are real numbers or appear as complex conjugate pairs respectively; d and h are real numbers; n is the number of poles, and a _i , c _i , d and h of different elements in the FDNE matrix are different identical.

It can be understood that when the poles of the N ² rational functions are different, applying the N ² elements in the FDNE matrix to the time-domain simulation one by one, the calculation amount will increase sharply, and the time-domain implementation is inconvenient, and the fast vector The fitting method can effectively reduce the amount of calculation.

According to the method for transient calculation of closed loop current based on frequency domain analysis proposed in the embodiment of the present invention, the transient calculation of closed loop current can be realized through the fast vector fitting method based on frequency domain analysis, which overcomes the accuracy and speed of transient calculation of closed loop current. The shortcomings that cannot be fully satisfied can effectively improve the accuracy and speed of calculation, and further improve the reliability of power supply to ensure the normal production and life of users.

Next, a closed loop current transient calculation device based on frequency domain analysis proposed according to an embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 4 is a schematic structural diagram of a closed loop current transient calculation device based on frequency domain analysis according to an embodiment of the present invention.

As shown in FIG. 4 , the closed loop current transient calculation device 10 based on frequency domain analysis includes: an acquisition module 100 , a first fitting module 200 , a judgment module 300 , a second fitting module 400 and a calculation module 500 .

Wherein, the acquisition modulo 100 is used to acquire a set of identical initial common poles in the N ² elements. The first fitting module 200 is configured to perform vector fitting on each element of the FDNE matrix one by one according to the initial common pole, so as to ensure that the poles and the number of each element are the same. The judging module 300 is used to obtain a new set of common poles after the vector fitting ends if the poles are not converged. The second fitting module 400 is configured to perform vector fitting again using the new common pole as the initial common pole, until the difference between the initial common pole and the new common pole is within a preset threshold, and obtain an FDNE matrix with common poles. The calculation module 500 solves the closed loop transient current. The device 10 in the embodiment of the present invention can realize the closed loop current transient calculation through the fast vector fitting method based on frequency domain analysis, improve the calculation accuracy and speed, further improve the reliability of power supply, and ensure the normal production and life of users.

Further, in an embodiment of the present invention, the obtaining module 100 further includes: a first obtaining unit, a calculating unit, a fitting unit and a second obtaining unit.

Wherein, the first obtaining unit is configured to obtain N N×N-dimensional sampling value matrices if the number of sampling points is N ₀ . The computing unit is configured to sequentially add N ² element values in each sample value matrix in the N N×N-dimensional sample value matrices, so as to obtain an N ₀ ×1 sample value vector. The fitting unit is used to perform vector fitting on a vector of sampled values to obtain a rational function. The second obtaining unit is used to obtain the poles of the rational function to obtain the initial common pole.

Further, in an embodiment of the present invention, each element of the FDNE matrix with a common pole is a frequency domain function:

Among them, the pole a _i and the residue c _i are real numbers or complex conjugate pairs, d and h are real numbers, n is the number of poles, and s is the complex frequency.

Further, in an embodiment of the present invention, the computing module 500 further includes: a establishing unit. Among them, the establishment unit is used to establish the FDNE equivalent model to solve the closed loop transient current, where the relationship between the voltage and current of the transmission network can be expressed as:

Among them, I _B is the current of the boundary bus, I _E is the current of the other buses except the boundary bus, U _E is the voltage of the other buses except the boundary bus, U _B is the voltage of the boundary bus, f is the frequency, the subscript B is the boundary bus, the lower Mark E is other busbars in the transmission network;

To get the FDNE matrix and Norton equivalent current after shrinking to the boundary, and the Norton equivalent current is:

Among them, f ₀ is the fundamental frequency.

Further, in an embodiment of the present invention, the apparatus 10 of the embodiment of the present invention further includes: converting the Norton equivalent current into a three-phase current source; and performing differential on the three-phase current source through an implicit trapezoidal method.

It should be noted that the foregoing explanation of the embodiment of the closed loop current transient calculation method based on frequency domain analysis is also applicable to the closed loop current transient calculation device based on frequency domain analysis in this embodiment, and will not be repeated here.

According to the closed loop current transient calculation device based on the frequency domain analysis proposed in the embodiment of the present invention, the closed loop current transient calculation can be realized through the fast vector fitting method based on the frequency domain analysis, which overcomes the accuracy and speed of the closed loop current transient calculation. The shortcomings that cannot be fully satisfied can effectively improve the accuracy and speed of calculation, and further improve the reliability of power supply to ensure the normal production and life of users.

In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", " Rear, Left, Right, Vertical, Horizontal, Top, Bottom, Inner, Outer, Clockwise, Counterclockwise, Axial, The orientations or positional relationships indicated by "radial direction", "circumferential direction", etc. are based on the orientations or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying the indicated devices or elements. It must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be construed as a limitation of the present invention.

In addition, the terms "first" and "second" are only used for descriptive purposes, and should not be construed as indicating or implying relative importance or implying the number of indicated technical features. Thus, a feature delimited with "first", "second" may expressly or implicitly include at least one of that feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise expressly and specifically defined.

In the present invention, unless otherwise expressly specified and limited, the terms "installed", "connected", "connected", "fixed" and other terms should be understood in a broad sense, for example, it may be a fixed connection or a detachable connection , or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between the two elements, unless otherwise specified limit. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

In the present invention, unless otherwise expressly specified and limited, a first feature "on" or "under" a second feature may be in direct contact between the first and second features, or the first and second features indirectly through an intermediary touch. Also, the first feature being "above", "over" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is level higher than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature has a lower level than the second feature.

In the description of this specification, description with reference to the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples", etc., mean specific features described in connection with the embodiment or example , structure, material or feature is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, those skilled in the art may combine and combine the different embodiments or examples described in this specification, as well as the features of the different embodiments or examples, without conflicting each other.

Although the embodiments of the present invention have been shown and described above, it should be understood that the above-mentioned embodiments are exemplary and should not be construed as limiting the present invention. Embodiments are subject to variations, modifications, substitutions and variations.

Claims (10)

1. a kind of Alloy White Iron Method for Transient Calculation based on frequency-domain analysis, which comprises the following steps:

Obtain N²One group of identical initial public pole in a element；

Vector fitting is carried out to each element of FDNE matrix according to the initial public pole, one by one to guarantee each member The pole and its number of element are identical；

If pole is not converged, one group of newly public pole is obtained after vector fitting；

Vector fitting is re-started using the new public pole as the initial public pole, until the initial public pole Difference with the new public pole obtains the FDNE matrix with public pole in predetermined threshold level；And

Solve cyclization transient current.

2. the Alloy White Iron Method for Transient Calculation according to claim 1 based on frequency-domain analysis, which is characterized in that described to obtain Take N²One group of identical initial public pole in a element further comprises:

If sampling number is N₀, then the sampling value matrix of N number of N × N-dimensional is sought；

By N in sampling value matrix each in the sampling value matrix of N number of N × N-dimensional²A element value is successively added, to obtain N₀× 1 sampled value vector；

Vector fitting is carried out to the sampled value vector, obtains rational function；

The pole for obtaining the rational function obtains the initial public pole.

3. the Alloy White Iron Method for Transient Calculation according to claim 1 based on frequency-domain analysis, which is characterized in that the tool The each element for having the FDNE matrix of public pole is a frequency-domain function:

Wherein, pole a_iWith residual c_iIt for real number or is complex conjugate pair, d and h are real number, and n is pole number, and s is complex frequency.

4. the Alloy White Iron Method for Transient Calculation according to claim 1 based on frequency-domain analysis, which is characterized in that described to ask Cyclization transient current is solved, further comprises:

FDNE Equivalent Model is established, to solve cyclization transient current, wherein power transmission network voltage and current relationship can indicate Are as follows:

Wherein, I_BFor boundary bus current, I_EFor other bus currents, U in addition to the bus of boundary_EFor other mothers in addition to the bus of boundary Line voltage, U_BFor boundary busbar voltage, f is frequency, and subscript B is boundary bus, and subscript E is other buses in power transmission network；

To obtain being retracted to FDNE matrix and Nuo Dun equal currents behind boundary, and the promise equal currents are as follows:

Wherein, f₀For fundamental frequency.

5. the Alloy White Iron Method for Transient Calculation according to claim 4 based on frequency-domain analysis, which is characterized in that also wrap It includes:

Three-phase current source is converted by the promise equal currents；

Difference is carried out to the three-phase current source by implicit trapezoid method.

6. a kind of Alloy White Iron Transient calculation device based on frequency-domain analysis characterized by comprising

Module is obtained, for obtaining N²One group of identical initial public pole in a element；

First fitting module, it is quasi- for carrying out vector one by one to each element of FDNE matrix according to the initial public pole It closes, pole and its number to guarantee each element are identical；

If judgment module obtains one group of newly public pole not converged for pole after vector fitting；

Second fitting module, for re-starting vector fitting for the new public pole as the initial public pole, directly To the difference of the initial public pole and the new public pole in predetermined threshold level, the FDNE with public pole is obtained Matrix；And

Computing module solves cyclization transient current.

7. the Alloy White Iron Transient calculation device according to claim 6 based on frequency-domain analysis, which is characterized in that described to obtain Modulus block further comprises:

First acquisition unit, if being N for sampling number₀, then the sampling value matrix of N number of N × N-dimensional is sought；

Computing unit is used for N in sampling value matrix each in the sampling value matrix of N number of N × N-dimensional²A element value successively phase Add, to obtain N₀× 1 sampled value vector；

Fitting unit obtains rational function for carrying out vector fitting to the sampled value vector；

Second acquisition unit obtains the initial public pole for obtaining the pole of the rational function.

8. the Alloy White Iron Transient calculation device according to claim 6 based on frequency-domain analysis, which is characterized in that the tool The each element for having the FDNE matrix of public pole is a frequency-domain function:

Wherein, pole a_iWith residual c_iIt for real number or is complex conjugate pair, d and h are real number, and n is pole number, and s is complex frequency.

9. the Alloy White Iron Transient calculation device according to claim 6 based on frequency-domain analysis, which is characterized in that the meter Module is calculated, further comprises:

Unit is established, for establishing FDNE Equivalent Model, to solve cyclization transient current, wherein power transmission network voltage and current Relationship can indicate are as follows:

Wherein, I_BFor boundary bus current, I_EFor other bus currents, U in addition to the bus of boundary_EFor other mothers in addition to the bus of boundary Line voltage, U_BFor boundary busbar voltage, f is frequency, and subscript B is boundary bus, and subscript E is other buses in power transmission network；

To obtain being retracted to FDNE matrix and Nuo Dun equal currents behind boundary, and the promise equal currents are as follows:

Wherein, f₀For fundamental frequency.

10. the Alloy White Iron Method for Transient Calculation according to claim 9 based on frequency-domain analysis, which is characterized in that also wrap It includes:

Three-phase current source is converted by the promise equal currents；

Difference is carried out to the three-phase current source by implicit trapezoid method.