Optimal parameter acquisition method and system for short-circuit current operation curve of synchronous motor, computer equipment and storage medium

Abstract

The invention provides an optimal parameter acquisition method and system for drawing a short-circuit current operation curve of a synchronous motor, computer equipment and a storage medium, and belongs to the field of short-circuit current calculation in the power industry. Preparing electromagnetic parameters of a plurality of synchronous motor samples; solving an arithmetic mean value of the electromagnetic parameters as an initial value; setting and calculating different external reactance of the short-circuit current and calculating time; constructing an objective function by using a least square method to solve deviation values of the initial value and the electromagnetic parameters of the motor sample at different external reactance and different calculation moments; increasing or decreasing the initial values one by one to obtain a group of electromagnetic parameters again, and solving the deviation value again; and changing the change direction of the electromagnetic parameters or reducing the tentative step length until the obtained deviation value is no longer reduced compared with the deviation value of the last time, and determining the group of electromagnetic parameters as the found optimal parameters. According to the method, the operation curve drawn based on the optimal parameters can be provided, and the obtained short-circuit current value can meet the engineering use precision requirement.

Description

Technical Field

[0001] This invention relates to the field of short-circuit current calculation in the power industry, and in particular to a method, system, computer equipment, and storage medium for obtaining the optimal parameters of the short-circuit current calculation curve of a synchronous motor. Background Technology

[0002] In power industry short-circuit current calculations, when determining the three-phase short-circuit current at the terminals of a synchronous motor, the periodic and aperiodic components of the three-phase short-circuit current decay with different time constants due to the influence of the synchronous motor's electromagnetic characteristics. Furthermore, since the electromagnetic parameters of each synchronous motor are different, the rate of decay of its short-circuit current varies. Accurately calculating the three-phase short-circuit current at the terminals of each synchronous motor requires separate calculations using the individual electromagnetic parameters of each motor. The calculation process, as described below, is quite complex and inconvenient in daily engineering design.

[0003] The following mathematical expression for the short-circuit current can be obtained from the general equations of a synchronous machine: d-axis short-circuit current: (1) In the formula: ; ; Second; The increase in no-load potential caused by forced excitation.

[0004] ; The maximum value multiple of forced excitation is generally taken as... 1.80.

[0005] q-axis short-circuit current: (2)

[0006] The excitation system of a self-excited generator (motor) is powered by the terminal voltage of the motor. The no-load electromotive force of the motor can be obtained from the normal operating mode of the motor. Its terminal voltage The relationship.

[0007] : hour, ; (3) You can take (4) (5) From equations (1), (2), and (5), we obtain the analytical formula for calculating the self-excited motor:

[0008]

[0009] (6)

[0010] ,but ; The short-circuit current of the self-excited motor can be directly calculated from equation (6).

[0011] As can be seen from the above, directly calculating the short-circuit current of a synchronous motor using electromagnetic parameters is quite complex. It would be much more convenient if the short-circuit current of a synchronous motor could be easily obtained by consulting scientifically plotted curves or tables, with an accuracy sufficient for engineering design requirements.

[0012] The computational curve method in practical calculations can easily determine the short-circuit current of synchronous motors, greatly reducing the computational burden on engineers while still meeting the accuracy requirements of engineering design. This method requires plotting a set of curves that can represent the short-circuit current decay patterns of the vast majority of synchronous motors in the industry.

[0013] Use any synchronous motor with 11 electromagnetic parameters ( The saturation value of the d-axis subtransient reactance; The unsaturated value of the d-axis subtransient reactance; The saturation value of the d-axis transient reactance; The unsaturated value of the d-axis transient reactance; d-axis synchronous reactance; :q-axis subtransient reactance; : q-axis synchronous reactance; Rated power factor of the motor; d-axis open-circuit subtransient time constant; d-axis open-circuit transient time constant; The operation curve of a synchronous motor, i.e., the operation function, can be obtained by using the above formula (6) (q-axis open-circuit subtransient time constant):

[0014] To plot a set of transport curves that represent the short-circuit current of most synchronous motors in the industry, with calculation errors within an acceptable range for engineering design, the first step is to find a set of optimized parameters that can represent these synchronous motors.

[0015] Currently, the electromagnetic optimization parameters used in plotting the calculation curves are obtained by collecting the electromagnetic parameters of most synchronous motors in the industry at that time and calculating their arithmetic average. Therefore, the short-circuit current value obtained using this set of curves has a certain error compared with the actual short-circuit current value of the synchronous motor. Although the error is acceptable for engineering applications, finding a more scientific and reasonable standard parameter would be very meaningful for improving the calculation accuracy. Summary of the Invention

[0016] To address the technical problems existing in the prior art, this invention provides a method, system, computer equipment, and storage medium for obtaining the optimal parameters of the short-circuit current calculation curve of a synchronous motor, employing the following technical solution.

[0017] This invention provides a method for obtaining the optimal parameters of the short-circuit current calculation curve of a synchronous motor, comprising the following steps: S1, collect electromagnetic parameters related to the calculation curve from multiple sets of salient-pole synchronous motor samples in the industry, wherein the number of multiple sets is greater than a preset number; S2, setting multiple external reactors for synchronous motors When calculating multiple short-circuit currents, the number of external reactors connected to the synchronous motor is greater than the first preset number, and the number of short-circuit current calculation times is greater than the second preset number. S3, calculate the arithmetic mean of the electromagnetic parameters in multiple sets of motor samples as the initial value of the electromagnetic parameters; S4, Calculate the initial values ​​of the electromagnetic parameters and the electromagnetic parameters of multiple sets of motor samples in the external reactance of multiple synchronous motors. The first deviation value at different short-circuit current calculation times; S5, gradually increase or decrease the initial value of the electromagnetic parameter by trial step. A new set of electromagnetic parameters is obtained, and the results are calculated again using this set of electromagnetic parameters and multiple sets of sample parameters in the external reactance of multiple synchronous motors. The second deviation value at different short-circuit current calculation times; S6. Compare the first deviation value and the second deviation value. If the second deviation value shows an increasing trend, change the direction of change of the electromagnetic parameters or reduce the trial step size to obtain a new set of electromagnetic parameters. If the second deviation value shows a decreasing trend, maintain the direction of change of the electromagnetic parameters or increase the trial step size to obtain a new set of electromagnetic parameters. S7. Repeat step S6 until the obtained electromagnetic parameters change without the deviation value decreasing compared to the previous deviation value. Then, this set of electromagnetic parameters is the optimal parameter found.

[0018] Preferably, step S1 specifically includes the following steps: the electromagnetic parameters related to the calculation curve include: The saturation value of the d-axis subtransient reactance; The unsaturated value of the d-axis subtransient reactance; The saturation value of the d-axis transient reactance; The unsaturated value of the d-axis transient reactance; d-axis synchronous reactance; :q-axis subtransient reactance; : q-axis synchronous reactance; Rated power factor of the motor; d-axis open-circuit subtransient time constant; d-axis open-circuit transient time constant; :q-axis open-circuit subtransient time constant.

[0019] Preferably, the circuit for plotting the operation curve includes an automatic excitation regulator, one end of which is connected to the rotor winding of the synchronous motor, and the other end is connected to the output of the synchronous motor. The output of the synchronous motor is connected to the variable reactance. Connection, where Represents the saturation value of the subtransient synchronous reactance of the synchronous motor. The sum of the per-unit reactance values ​​of the equipment connected to the synchronous motor, during the plotting of the calculation curve. The value is increased as a function variable until the short-circuit current no longer changes.

[0020] Preferably, , , and The vector diagram of the synchronous motor under its rated operating mode is obtained using the following method: exist , hour:

[0021]

[0022]

[0023]

[0024]

[0025]

[0026]

[0027] ; in, Power factor; The power factor angle; For the angle of attack; It is the complementary angle of the sum of the power factor angle and the power angle; Stator current Components along the direct d-axis; Stator current The components along the q-axis; Stator voltage The components along the q-axis; Stator voltage Components along the direct d-axis; This is the per-unit value of the stator voltage; This is the per-unit value of the stator current; This represents the q-axis subtransient potential in the vector diagram. This represents the transient potential along the q-axis in the vector diagram. The q-axis represents the no-load potential in the vector diagram; This represents the d-axis subtransient potential in the vector diagram.

[0028] Preferably, in step S6, for any electromagnetic parameter The optimal electromagnetic parameters are obtained using the following method: S600, input the initial value of any electromagnetic parameter. The initial values ​​of the allowable error ε, the trial step size Δ, and the step size extending along the valley line. α The initial values ​​are given, where the step size α extending along the valley line is larger than the trial step size Δ; let the initial electromagnetic parameters be the starting point for the current optimal electromagnetic parameters. ,Right now Electromagnetic parameters for calculating short-circuit current of synchronous motors; S601, recording the initial design starting point. , that is to say ; S602, The electromagnetic parameters are composed of starting points in the positive, negative, and zero directions, multiplied by the direction vector. To calculate the increase or decrease of the objective function value, from the first parameter i=1 to the last parameter i=11, the following process is executed until the last parameter: If the objective function decreases when the trial step size Δ is increased in the positive direction, then the optimal point found is recorded. If the objective function does not decrease, then increase the trial step size Δ in the negative direction; if the objective function decreases, then record the best point found. Otherwise, record the best point found. ; Define the found optimal point as the new starting point, that is, let ; S603, record the new starting point as the comparison point. , Right now ; S604, Judgment from a new starting point After testing, can we find a position where the objective function continues to decrease? If not found, proceed to step S605; if found successfully, proceed to step S606. S605, reduce the trial step size Δ by half. If the trial step size has reached the allowable error ε, then Comparison points Starting with records , that is to say Proceed to step S602 and begin a new iteration; S606, Following the success of step S604, find the direction from which the objective function continues to decrease, i.e., the valley line. Direction, using the valley line step length α as the step size to enter the next point. To find the optimal parameters, such as If the objective function of a point decreases, the valley step size α is increased to continue searching for optimal parameters; otherwise, points are compared. Starting with records , that is to say Proceed to step S602 to explore new optimal directions.

[0029] Preferably, in step S6, the objective function for:

[0030] In the formula: k =1- n , n Number of samples; t =0-4.0s; =0.16-3.4; The optimal parameters to be found At different calculation times for the 11 parameters set in step S2 t , The short-circuit current obtained from 0.16 to 3.40; For use of the first k Actual parameters of the sample motor At different calculation times set in step S2, different The obtained short-circuit current.

[0031] Preferably, the synchronous motor is connected to an external reactor. The incremental growth is 0.02.

[0032] Preferably, the short-circuit current calculation time includes 0.0s, 0.01s, 0.06s, 0.1s, 0.2s, 0.4s, 0.5s, 0.6s, 1.0s, 2.0s, and 4.0s.

[0033] The present invention also provides a system for obtaining the short-circuit current of a synchronous motor, including a processor, the processor being able to execute a computer program, the computer program being able to implement the above-mentioned method for obtaining the optimal parameters of the short-circuit current calculation curve of a synchronous motor.

[0034] The present invention also provides a computer device, including a processor, the processor being capable of executing a computer program, the computer program being capable of implementing the above-described method for obtaining the optimal parameters of the synchronous motor short-circuit current calculation curve.

[0035] The present invention also provides a storage medium storing a computer program, which, when executed, can implement the above-described method for obtaining the optimal parameters of the synchronous motor short-circuit current calculation curve.

[0036] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The present invention obtains the initial values ​​of the electromagnetic parameters and the electromagnetic parameters of multiple sets of motor samples in the external reactance of multiple synchronous motors. Using the first deviation value at different short-circuit current calculation times, the initial values ​​of the electromagnetic parameters are increased or decreased step by step to obtain a new set of electromagnetic parameters. This new set of electromagnetic parameters is then compared with multiple sets of sample parameters in the external reactance of multiple synchronous motors. The first deviation value is compared with the second deviation value at different short-circuit current calculation times. If the second deviation value shows an increasing trend, the direction of electromagnetic parameter change or the trial step size is reduced to obtain a new set of electromagnetic parameters. If the second deviation value shows a decreasing trend, the direction of electromagnetic parameter change or the trial step size is maintained to obtain a new set of electromagnetic parameters. The search for optimal electromagnetic parameters is repeated until the obtained electromagnetic parameters, regardless of how they change, no longer decrease in deviation value compared to the previous deviation value. Then, this set of electromagnetic parameters is the optimal parameter found. The calculation curve plotted using this set of optimal parameters will be the most accurate calculation curve. This invention can improve the calculation accuracy of the calculation curve method, provide a more accurate design basis for engineering design, and thus create economic value.

[0037] (2) The present invention uses the error analysis method in statistics to analyze the error between the short-circuit current obtained by the calculation curve drawn by the method of the present invention and the actual short-circuit current of all sample synchronous motors. When the expected error of the short-circuit current calculated by the calculation curve drawn by the optimal parameters obtained by this method and all original sample parameters is 1.4203%, the proportion reaches 73%. Attached Figure Description

[0038] 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 some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0039] Figure 1 A flowchart illustrating a method for obtaining optimal parameters of a synchronous motor short-circuit current calculation curve according to an embodiment of the present invention; Figure 2 This is a flowchart illustrating the search for optimal electromagnetic parameters according to the present invention. Figure 3 This is a circuit diagram for plotting the computation curve according to the present invention.

[0040] Figure 4 This is a vector diagram of the rated operating mode of the motor G in this invention. Detailed Implementation

[0041] The specific embodiments of the present invention will be described in detail below.

[0042] like Figures 1-4 As shown, this invention provides a method for obtaining the optimal parameters of the short-circuit current calculation curve of a synchronous motor, comprising the following steps: S1, collect electromagnetic parameters related to the calculation curve from multiple sets of salient-pole synchronous motor samples in the industry, wherein the number of multiple sets is greater than a preset number; S2, setting multiple external reactors for synchronous motors When calculating multiple short-circuit currents, the number of external reactors connected to the synchronous motor is greater than the first preset number, and the number of short-circuit current calculation times is greater than the second preset number. S3, calculate the arithmetic mean of the electromagnetic parameters in multiple sets of motor samples as the initial value of the electromagnetic parameters; S4, Calculate the initial values ​​of the electromagnetic parameters and the electromagnetic parameters of multiple sets of motor samples in the external reactance of multiple synchronous motors. The first deviation value at different short-circuit current calculation times; S5, gradually increase or decrease the initial value of the electromagnetic parameter by trial step. A new set of electromagnetic parameters is obtained, and the results are calculated again using this set of electromagnetic parameters and multiple sets of sample parameters in the external reactance of multiple synchronous motors. The second deviation value at different short-circuit current calculation times; S6. Compare the first deviation value and the second deviation value. If the second deviation value shows an increasing trend, change the direction of change of the electromagnetic parameters or reduce the trial step size to obtain a new set of electromagnetic parameters. If the second deviation value shows a decreasing trend, maintain the direction of change of the electromagnetic parameters or increase the trial step size to obtain a new set of electromagnetic parameters. S7. Repeat step S6 until the obtained electromagnetic parameters change without the deviation value decreasing compared to the previous deviation value. Then, this set of electromagnetic parameters is the optimal parameter found.

[0043] According to a specific embodiment of the present invention, step S1 specifically includes the following steps: the electromagnetic parameters related to the calculation curve include: The saturation value of the d-axis subtransient reactance; The unsaturated value of the d-axis subtransient reactance; The saturation value of the d-axis transient reactance; The unsaturated value of the d-axis transient reactance; d-axis synchronous reactance; :q-axis subtransient reactance; : q-axis synchronous reactance; Rated power factor of the motor; d-axis open-circuit subtransient time constant; d-axis open-circuit transient time constant; :q-axis open-circuit subtransient time constant.

[0044] According to a specific embodiment of the present invention, the circuit for plotting the operation curve includes an automatic excitation regulator, one end of which is connected to the rotor winding of the synchronous motor, and the other end is connected to the output of the synchronous motor. The output of the synchronous motor is connected to a variable reactance. Connection, where Represents the saturation value of the subtransient synchronous reactance of the synchronous motor. The sum of the per-unit reactance values ​​of the equipment connected to the synchronous motor, during the plotting of the calculation curve. The value is increased as a function variable until the short-circuit current no longer changes.

[0045] According to a specific embodiment of the present invention, , , and The vector diagram of the synchronous motor under its rated operating mode is obtained using the following method: exist , hour:

[0046]

[0047]

[0048]

[0049]

[0050]

[0051]

[0052] ; in, Power factor; The power factor angle; For the angle of attack; It is the complementary angle of the sum of the power factor angle and the power angle; Stator current Components along the direct d-axis; Stator current The components along the q-axis; Stator voltage The components along the q-axis; Stator voltage Components along the direct d-axis; This is the per-unit value of the stator voltage; This is the per-unit value of the stator current; This represents the q-axis subtransient potential in the vector diagram. This represents the transient potential along the q-axis in the vector diagram. The q-axis represents the no-load potential in the vector diagram; This represents the d-axis subtransient potential in the vector diagram.

[0053] According to a specific embodiment of the present invention, in step S6, for any electromagnetic parameter The optimal electromagnetic parameters are obtained using the following method: S600, input the initial value of any electromagnetic parameter. The initial values ​​of the allowable error ε, the trial step size Δ, and the step size extending along the valley line. α The initial values ​​are given, where the step size α extending along the valley line is larger than the trial step size Δ; let the initial electromagnetic parameters be the starting point for the current optimal electromagnetic parameters. ,Right now Electromagnetic parameters for calculating short-circuit current of synchronous motors; S601, recording the initial design starting point. , that is to say ; S602, The electromagnetic parameters are composed of starting points in the positive, negative, and zero directions, multiplied by the direction vector. To calculate the increase or decrease of the objective function value, from the first parameter i=1 to the last parameter i=11, the following process is executed until the last parameter: If the objective function decreases when the trial step size Δ is increased in the positive direction, then the optimal point found is recorded. If the objective function does not decrease, then increase the trial step size Δ in the negative direction; if the objective function decreases, then record the best point found. Otherwise, record the best point found. ; Define the found optimal point as the new starting point, that is, let ; S603, record the new starting point as the comparison point. , Right now ; S604, Judgment from a new starting point After testing, can we find a position where the objective function continues to decrease? If not found, proceed to step S605; if found successfully, proceed to step S606. S605, reduce the trial step size Δ by half. If the trial step size has reached the allowable error ε, then Comparison points Starting with records , that is to say Proceed to step S602 and begin a new iteration; S606, Following the success of step S604, find the direction from which the objective function continues to decrease, i.e., the valley line. Direction, using the valley line step length α as the step size to enter the next point. To find the optimal parameters, such as If the objective function of a point decreases, the valley step size α is increased to continue searching for optimal parameters; otherwise, points are compared. Starting with records , that is to say Proceed to step S602 to explore new optimal directions.

[0054] According to a specific embodiment of the present invention, in step S6, the objective function for:

[0055] In the formula: k =1- n , n Number of samples; t =0-4.0s; =0.16-3.4; The optimal parameters to be found At different calculation times for the 11 parameters set in step S2 t , The short-circuit current obtained from 0.16 to 3.40; For use of the first k Actual parameters of the sample motor At different calculation times set in step S2, different The obtained short-circuit current.

[0056] The objective function is the squared difference between the short-circuit currents (Xjs) obtained at different times and corresponding times of other sample parameters, obtained by each step change of the electromagnetic parameters. The objective function reflects the closeness of two short-circuit currents. When the objective function no longer decreases, it is considered that the short-circuit current obtained from the optimal electromagnetic parameters is closest to the short-circuit current obtained from other sample motors; therefore, the optimal parameters at this point are the desired set of optimal parameters.

[0057] According to a specific embodiment of the present invention, the synchronous motor is connected to an external reactor. The incremental growth is 0.02.

[0058] According to a specific embodiment of the present invention, the short-circuit current calculation time includes 0.0s, 0.01s, 0.06s, 0.1s, 0.2s, 0.4s, 0.5s, 0.6s, 1.0s, 2.0s and 4.0s.

[0059] The present invention also provides a system for obtaining the short-circuit current of a synchronous motor, including a processor, the processor being able to execute a computer program, the computer program being able to implement the above-mentioned method for obtaining the optimal parameters of the short-circuit current calculation curve of a synchronous motor.

[0060] The present invention also provides a computer device, including a processor, the processor being capable of executing a computer program, the computer program being capable of implementing the above-described method for obtaining the optimal parameters of the synchronous motor short-circuit current calculation curve.

[0061] The present invention also provides a storage medium storing a computer program, which, when executed, can implement the above-described method for obtaining the optimal parameters of the synchronous motor short-circuit current calculation curve.

[0062] Example 1 This invention provides a method for obtaining the optimal parameters of the short-circuit current calculation curve of a synchronous motor, comprising the following steps: S1, collect electromagnetic parameters related to the calculation curve from multiple sets of salient-pole synchronous motor samples in the industry, wherein the number of multiple sets is greater than a preset number; S2, setting multiple external reactors for synchronous motors When calculating multiple short-circuit currents, the number of external reactors connected to the synchronous motor is greater than the first preset number, and the number of short-circuit current calculation times is greater than the second preset number. S3, calculate the arithmetic mean of the electromagnetic parameters in multiple sets of motor samples as the initial value of the electromagnetic parameters; S4, Calculate the initial values ​​of the electromagnetic parameters and the electromagnetic parameters of multiple sets of motor samples in the external reactance of multiple synchronous motors. The first deviation value at different short-circuit current calculation times; S5, gradually increase or decrease the initial value of the electromagnetic parameter by trial step. A new set of electromagnetic parameters is obtained, and the results are calculated again using this set of electromagnetic parameters and multiple sets of sample parameters in the external reactance of multiple synchronous motors. The second deviation value at different short-circuit current calculation times; S6. Compare the first deviation value and the second deviation value. If the second deviation value shows an increasing trend, change the direction of change of the electromagnetic parameters or reduce the trial step size to obtain a new set of electromagnetic parameters. If the second deviation value shows a decreasing trend, maintain the direction of change of the electromagnetic parameters or increase the trial step size to obtain a new set of electromagnetic parameters. S7. Repeat step S6 until the obtained electromagnetic parameters change without the deviation value decreasing compared to the previous deviation value. Then, this set of electromagnetic parameters is the optimal parameter found.

[0063] Example 2 Unlike Example 1, in step S6, for any electromagnetic parameter The optimal electromagnetic parameters are obtained using the following method: S600, input the initial value of any electromagnetic parameter. The initial values ​​of the allowable error ε, the trial step size Δ, and the step size extending along the valley line. α The initial values ​​are given, where the step size α extending along the valley line is larger than the trial step size Δ; let the initial electromagnetic parameters be the starting point for the current optimal electromagnetic parameters. ,Right now Electromagnetic parameters for calculating short-circuit current of synchronous motors; S601, recording the initial design starting point. , that is to say ; S602, the starting point composed of electromagnetic parameters is divided into positive direction, negative direction, and zero direction by multiplying by the direction vector. To calculate the increase or decrease of the objective function value, from the first parameter i=1 to the last parameter i=11, the following process is executed until the last parameter: If the objective function decreases when the trial step size Δ is increased in the positive direction, then the optimal point found is recorded. If the objective function does not decrease, then increase the trial step size Δ in the negative direction; if the objective function decreases, then record the best point found. Otherwise, record the best point found. ; Define the found optimal point as the new starting point, that is, let ; S603, record the new starting point as the comparison point. , Right now ; S604, Judgment from a new starting point After testing, can we find a position where the objective function continues to decrease? If not found, proceed to step S605; if found successfully, proceed to step S606. S605, reduce the trial step size Δ by half. If the trial step size has reached the allowable error ε, then Comparison points Starting with records , that is to say Proceed to step S602 and begin a new iteration; S606, Following the success of step S604, find the direction from which the objective function continues to decrease, i.e., the valley line. Direction, using the valley line step length α as the step size to enter the next point. To find the optimal parameters, such as If the objective function of a point decreases, the valley step size α is increased to continue searching for optimal parameters; otherwise, points are compared. Starting with records , that is to say Proceed to step S602 to explore new optimal directions.

[0064] Furthermore, in step S6, the objective function for:

[0065] In the formula: k =1- n , n Number of samples; t =0-4.0s; =0.16-3.4; The optimal parameters to be found At different calculation times for the 11 parameters set in step S2 t , The short-circuit current obtained from 0.16 to 3.40; For use of the first k Actual parameters of the sample motor At different calculation times set in step S2, different The obtained short-circuit current.

[0066] Furthermore, the external reactor of the synchronous motor The incremental growth is 0.02.

[0067] Furthermore, the short-circuit current calculation times include 0.0s, 0.01s, 0.06s, 0.1s, 0.2s, 0.4s, 0.5s, 0.6s, 1.0s, 2.0s, and 4.0s.

[0068] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of protection of the present invention.

Claims

1. A method for obtaining optimal parameters of a short-circuit current operating curve of a synchronous machine, characterized in that, The method comprises the following steps: S1, collecting electromagnetic parameters related to the operation curve in a plurality of groups of salient-pole synchronous motor samples in the industry, the plurality of groups being greater than a preset group number; S2, setting a plurality of synchronous motor external reactance and the number of short-circuit current calculation moments is greater than a preset second number. S3, obtaining the arithmetic mean of the electromagnetic parameters in the plurality of motor samples as the initial value of the electromagnetic parameters ; S4, obtaining the first deviation value between the initial value of the electromagnetic parameter and the electromagnetic parameter of the plurality of synchronous motor samples in the outer reactance of the plurality of synchronous motors and different short-circuit current calculation moments; S5, increasing or decreasing the initial value of the electromagnetic parameter by a trial step length one by one , obtaining a new set of electromagnetic parameters, and calculating the second deviation value of the new set of electromagnetic parameters and the plurality of sets of sample parameters at the plurality of synchronous motor outer reactance and different short-circuit current calculation time S6, comparing the first deviation value and the second deviation value, if the second deviation value has an increasing trend, changing the electromagnetic parameter change direction or reducing the trial step, and re-obtaining a group of electromagnetic parameters; if the second deviation value has a decreasing trend, keeping the electromagnetic parameter change direction or increasing the trial step, and re-obtaining a group of electromagnetic parameters; S7, repeating step S6 until the obtained electromagnetic parameters change in any way, and the obtained deviation value is no longer reduced compared with the last deviation value, and then the group of electromagnetic parameters is the optimal parameters found.

2. The method of claim 1, wherein The step S1 specifically comprises the following steps: the electromagnetic parameters related to the operation curve comprise: : saturated value of d-axis sub-transient reactance; : unsaturated value of d-axis sub-transient reactance; : saturated value of d-axis transient reactance; : unsaturated value of d-axis transient reactance; : d-axis synchronous reactance; : q-axis sub-transient reactance; : q-axis synchronous reactance; : rated power factor of the motor; : d-axis open-circuit sub-transient time constant; : d-axis open-circuit transient time constant; : q-axis open-circuit sub-transient time constant.

3. The method of claim 2, wherein The circuit for drawing the operating curve comprises an automatic excitation regulator, one end of which is connected to the rotor winding of the synchronous machine and the other end is connected to the outlet of the synchronous machine, the outlet of the synchronous machine being connected with the variable reactance , wherein represents the sum of the reactance per unit of the synchronous machine and the equipment connected to the synchronous machine, and during the drawing of the operating curve is increased as a function variable until the short-circuit current no longer changes.

4. The method of claim 2, wherein , , and The vector diagram according to the rated mode of operation of the synchronous machine is obtained in the following way: At , time: ； Wherein, Power factor; cos φ is the power factor angle; is the power angle; the sum of the power factor angle and the power angle; for the stator current component in the direct axis d-axis; for the stator current in the quadrature axis q for the stator voltage in the quadrature axis q for the stator voltage component in the direct axis d-axis; Vn is the nominal value of the stator voltage; is the stator current norm; q-axis sub-transient potential in the vector diagram; q-axis transient potential in the vector diagram; Vq is the open circuit potential for the q-axis in the vector diagram; is the d-axis sub-transient potential in the vector diagram.

5. The method of claim 1, wherein In step S6, for any electromagnetic parameter The optimal electromagnetic parameters are obtained by using the following method: S600, input initial value of any electromagnetic parameter , initial value of error ε, initial value of trial step Δ and step along valley line α α , initial value of error ε, initial value of trial step Δ and step along valley line α, wherein step along valley line α is larger than trial step Δ; let initial electromagnetic parameter be starting point of current optimal electromagnetic parameter , i.e. ; electromagnetic parameter for calculating short-circuit current of synchronous motor S601, record the initial departure point i.e. ; S602, the starting point composed of electromagnetic parameters in the positive direction, negative direction, 0 direction, through the multiplication of direction vector , calculate the increase and decrease of the objective function value, from the first parameter i=1 to the last parameter i=11, execute the following process until the last parameter: If the objective function decreases, record the best point found If the objective function does not decrease, increase the step size Δ in the negative direction, and if the objective function decreases, record the best point found Otherwise, record the best point found ; Define the best point found as the new starting point, i.e., let ; S603, record the new departure point as a comparison point , i.e. ; S604, judging whether a new starting point is found whether a position is found to make the objective function continue to decline, and If not, go to step S605, and if yes, go to step S606. S605, the trial step Δ is reduced by half, if the trial step has reached the allowed error ε, the calculation is terminated, otherwise the comparison point Recorded as the departure point That is, let Go to step S602, start a new iteration; S606, along the direction of the successful finding of step S604, i.e. the valley line, to continue to descend the objective function direction, to the next point with a valley line step size α , find the optimal parameters, such as the objective function of the point is reduced, and the valley line step size α is enlarged to continue to find the optimal parameters, otherwise the point is recorded as the starting point , i.e. , go to step S602 to explore a new best direction again.

6. The method of claim 5, wherein In step S6, the objective function is: In the formula: k =1- n , n is the number of samples; t =0-4.0s; =0.16-3.4; for the optimal parameters to be sought ) at different calculation instants of 11 parameters set at step S2 t , short-circuit current from 0.16 to 3.40 obtained The actual parameters of the first k sample motor At different calculation instants set in step S2, different short-circuit currents are obtained.

7. The method of claim 6, wherein the optimal parameters of the short-circuit current operating curve of the synchronous machine are obtained by: External reactance of synchronous machine The step size is 0.

02.

8. The method of claim 6, wherein the optimal parameters of the short-circuit current operating curve of the synchronous machine are obtained by, The short-circuit current calculation time points include 0.0s, 0.01s, 0.06s, 0.1s, 0.2s, 0.4s, 0.5s, 0.6s, 1.0s, 2.0s and 4.0s.

9. A synchronous machine short circuit current determination system, characterized by The processor can execute a computer program, and the computer program can implement the optimal parameter acquisition method of the synchronous motor short-circuit current operation curve according to any one of claims 1-8.

10. A computer device, comprising: The processor can execute a computer program, and the computer program can implement the optimal parameter acquisition method of the synchronous motor short-circuit current operation curve according to any one of claims 1-8.

11. A storage medium, characterized by The computer program is stored and executed to implement the optimal parameter acquisition method of the synchronous motor short-circuit current operation curve according to any one of claims 1-8.

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