Method and apparatus for modeling electromechanical transient sixth order mathematical model of a distributed phase modifier

Abstract

The application discloses a modeling method and device for an electromechanical transient six-order mathematical model of a distributed phase modifier, and comprises the following steps: obtaining a q-axis rotor winding voltage equation and q-axis excitation winding current and damping winding current according to a Park equation of a two-axis excitation generator, a d-axis transient electromotive force and a sub-transient electromotive force; obtaining a differential equation of a q-axis rotor winding according to a traditional generator model and the q-axis rotor winding voltage equation; substituting q-axis transient reactance and sub-transient reactance into the differential equation of the q-axis rotor winding to obtain a first equation of q-axis state variables; obtaining a q-axis damping winding voltage equation and a q-axis winding resistance; obtaining a differential equation of a q-axis damping winding according to the q-axis damping winding resistance and the q-axis damping winding voltage equation; and obtaining a second equation of q-axis state variables according to basic assumptions in the traditional generator model and the differential equation of the q-axis damping winding. The application solves the problem of the demand for an electromechanical transient practical model in simulation analysis.

Description

Technical Field

[0001] This application relates to the field of mathematical modeling technology for motors and electrical appliances, specifically to a modeling method and apparatus for a sixth-order mathematical model of electromechanical transients for distributed synchronous condensers. Background Technology

[0002] The national clean energy strategy has provided a broad market prospect for the vigorous development of new energy. However, due to the fact that the voltage regulation, frequency regulation and high and low voltage ride-through capabilities of new energy units are far inferior to those of conventional units, the voltage support capability and frequency stability level of the power grid have declined significantly.

[0003] Currently, ultra-high voltage direct current (UHVDC) has become the main mode of renewable energy transmission. In UHVDC sending-end systems, with the gradual increase in the proportion of renewable energy, conventional generating units face severe challenges in maintaining stable system operation. First, conventional generators are limited by their own static stability limits, and with the significant increase in the proportion of renewable energy, the overall system's rotational inertia is insufficient, making it difficult for the system to maintain transient stability during severe fault impacts. Second, conventional generators are constrained by the minimum excitation current, limiting their phase-advancing capability and their ability to suppress transient and steady-state overvoltages during DC faults and recovery. Third, the dynamic stability problems caused by insufficient system damping are difficult to solve through PSS optimization of a small number of conventional units.

[0004] Meanwhile, in ultra-high voltage direct current (UHVDC) receiving-end systems, the large-scale DC inflow and the booming development of distributed energy have led to a gradual decrease in the number of local conventional generating units, resulting in a decline in the system's dynamic reactive power reserve and rotational inertia. This exacerbates the risks to system transient stability and voltage stability, placing higher demands on the voltage support capability and transient stability maintenance ability of individual generating units. For example, the generator's voltage regulation capability and ability to provide short-circuit current should be further improved to suppress transient overvoltages or transient undervoltages; frequency regulation capability should be more outstanding to compensate for the deficiencies caused by the reduction in system inertia and the decrease in frequency-regulating generating units; and it should have better stability to absorb a large amount of fault impact power and prevent power from being transferred to weak AC channels, causing the AC grid to lose stability.

[0005] Therefore, a dual-shaft excitation generator with superior stability has become a research hotspot in recent years. The unique feature of a dual-shaft excitation generator is that it has an excitation winding on each of the d and q axes. By adjusting the magnitude and direction of the excitation current on the d and q axes, the direction of the excitation magnetomotive force can be arbitrarily changed, ensuring that the generator's power angle remains within a reasonable range during transient processes, preventing it from losing synchronization due to static stability limits. Simultaneously, through coordinated control of the d and q axes, a synthetic magnetic field rotating relative to the rotor can be obtained, enabling asynchronous operation. During transient processes, it absorbs active power surges from the grid and converts them into rotor kinetic energy, significantly improving the system's shock resistance. Furthermore, the dual-shaft excitation generator can achieve independent control of active and reactive power. The d-axis excitation winding can be reversed to provide more than twice the rated power of the leading reactive power, while the q-axis excitation winding controls the generator to output the required active power, maintaining synchronous operation. This greatly improves the system's transient dynamic stability, voltage stability, and frequency stability. However, a practical electromechanical transient model for dual-shaft excitation distributed synchronous condensers suitable for large power grid simulation analysis has not yet been established. Summary of the Invention

[0006] To address the aforementioned problems and to study the dynamic characteristics of dual-axis excitation distributed synchronous condensers in large power grids and their impact on power systems, this application provides a modeling method for a sixth-order electromechanical transient mathematical model of distributed synchronous condensers, including:

[0007] Obtain the q-axis transient reactance, q-axis secondary reactance, d-axis transient electromotive force, and d-axis secondary transient electromotive force of the dual-axis exciter;

[0008] Based on the Park equation, d-axis transient electromotive force and d-axis subtransient electromotive force of the dual-axis excitation generator, the voltage equation of the q-axis rotor winding, the current of the q-axis excitation winding and the current of the q-axis damping winding are obtained.

[0009] Based on the traditional generator model and the voltage equation of the q-axis rotor winding, the differential equation of the q-axis rotor winding is obtained;

[0010] Substituting the q-axis transient reactance and the q-axis secondary reactance into the differential equation of the q-axis rotor winding, the first equation of the q-axis state variables of the dual-axis excitation generator is obtained.

[0011] Obtain the voltage equation and resistance of the q-axis damping winding; based on the resistance of the q-axis damping winding and the voltage equation of the q-axis damping winding, obtain the differential equation of the q-axis damping winding;

[0012] Based on the fundamental assumptions in the traditional generator model and the differential equation of the q-axis damping winding, the second equation for the q-axis state variables of the dual-axis excitation generator is obtained.

[0013] Furthermore, the q-axis transient reactance and q-axis sub-state reactance of the dual-axis excitation generator are obtained based on the Park equation and the q-axis operational reactance of the dual-axis excitation generator, specifically including:

[0014] By transforming the Park equations for the dual-shaft excitation generator and substituting them into the q-axis operational reactance, the q-axis transient reactance X′ of the dual-shaft excitation generator can be obtained according to the initial value theorem. q and q-axis secondary electric state reactance X″ q .

[0015] Furthermore, based on the Park equations, d-axis transient electromotive force, and d-axis subtransient electromotive force of the dual-shaft excitation generator, the q-axis rotor winding voltage equation, q-axis excitation winding current, and q-axis damping winding current are obtained, including:

[0016] Based on the induced electromotive force in the traditional generator model, determine the d-axis transient electromotive force E′. d and the d-axis subtransient electromotive force E″ d ;

[0017] The q-axis rotor winding voltage equation, q-axis excitation winding current, and q-axis damping winding current are obtained based on the Park equation.

[0018] Using the d-axis transient electromotive force E′ d and the d-axis subtransient electromotive force E″ d Replace the q-axis excitation winding flux and q-axis damping winding flux in the q-axis excitation winding current and the q-axis damping winding current to obtain the flux through E′ d and E″ d The currents represent the q-axis excitation winding current and the q-axis damping winding current.

[0019] Furthermore, based on the traditional generator model and the voltage equation of the q-axis rotor winding, the differential equation of the q-axis rotor winding is obtained, including:

[0020] By substituting the basic assumptions of the traditional generator model and the q-axis excitation winding current into the q-axis rotor winding voltage equation, the differential equation of the q-axis rotor winding is obtained.

[0021] Furthermore, based on the equations for the resistance and voltage of the q-axis damping winding, the differential equations for the q-axis damping winding are obtained, including:

[0022] Based on the Park equation, the voltage equation for the q-axis damping winding is obtained;

[0023] Based on the q-axis no-load open-circuit transient time constant T′ q0 and the q-axis no-load open-circuit subtransient time constant T″ q0 To obtain the resistance of the q-axis damping winding;

[0024] Substituting the resistance of the q-axis damping winding into the voltage equation of the q-axis damping winding, we obtain the differential equation of the q-axis damping winding.

[0025] Furthermore, based on the fundamental assumptions in the traditional generator model and the differential equation of the q-axis damping winding, the second equation for the q-axis state variables of the dual-shaft excitation generator is obtained, including:

[0026] Substituting the basic assumptions of the traditional generator model into the differential equation of the q-axis damping winding, we obtain the second equation for obtaining the q-axis state variables of the dual-axis excitation generator.

[0027] Furthermore, it also includes:

[0028] The first equation and the second equation are combined to generate the q-axis state variable equation of the dual-axis excitation generator.

[0029] This invention also provides a modeling apparatus for a sixth-order mathematical model of electromechanical transients in a distributed synchronous condenser, comprising:

[0030] The parameter acquisition unit is used to acquire the q-axis transient reactance, q-axis secondary reactance, d-axis transient electromotive force, and d-axis secondary transient electromotive force of the dual-axis excitation generator.

[0031] The q-axis rotor winding voltage equation acquisition unit is used to obtain the q-axis rotor winding voltage equation, q-axis excitation winding current, and q-axis damping winding current based on the Park equation, d-axis transient electromotive force, and d-axis subtransient electromotive force of the dual-axis excitation generator.

[0032] The first differential equation acquisition unit is used to obtain the differential equation of the q-axis rotor winding based on the traditional generator model and the voltage equation of the q-axis rotor winding.

[0033] The first equation acquisition unit is used to substitute the q-axis transient reactance and the q-axis secondary reactance into the differential equation of the q-axis rotor winding to obtain the first equation of the q-axis state variables of the dual-axis excitation generator.

[0034] The second differential equation acquisition unit is used to acquire the voltage equation of the q-axis damping winding and the resistance of the q-axis damping winding; based on the resistance of the q-axis damping winding and the voltage equation of the q-axis damping winding, the differential equation of the q-axis damping winding is obtained.

[0035] The second equation acquisition unit is used to obtain the second equation of the q-axis state variables of the dual-axis excitation generator based on the basic assumptions in the traditional generator model and the differential equation of the q-axis damping winding.

[0036] Furthermore, the rotor winding voltage equation acquisition unit includes:

[0037] The electromotive force determination sub-unit is used to determine the d-axis transient electromotive force E′ based on the induced electromotive force in a traditional generator model.d and the d-axis subtransient electromotive force E″ d ;

[0038] The voltage equation acquisition subunit is used to obtain the rotor winding voltage equation, q-axis excitation winding current and q-axis damping winding current according to the Park equation.

[0039] The winding current acquisition sub-unit is used to obtain the d-axis transient electromotive force E′. d and the d-axis subtransient electromotive force E″ d Replace the q-axis excitation winding flux and q-axis damping winding flux in the q-axis excitation winding current and the q-axis damping winding current to obtain the flux through E′ d and E″ d The currents represent the q-axis excitation winding current and the q-axis damping winding current.

[0040] Furthermore, it also includes:

[0041] The variable equation generation unit is used to combine the first equation and the second equation to generate the q-axis state variable equation of the dual-axis excitation generator.

[0042] The present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of any of the methods described above.

[0043] The present invention also provides a readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of the method described in any of the above-mentioned embodiments.

[0044] The present invention provides a modeling method and apparatus for a sixth-order mathematical model of electromechanical transients for distributed synchronous condensers, which solves the current problem of the need for practical models of electromechanical transients in simulation analysis. Attached Figure Description

[0045] Figure 1 This is a flowchart illustrating a modeling method for a sixth-order mathematical model of electromechanical transients for distributed synchronous condensers, provided in an embodiment of the present invention.

[0046] Figure 2 This is a schematic diagram of the electrical quantity reference direction of a dual-shaft excitation generator according to an embodiment of the present invention;

[0047] Figure 3 This is an equivalent circuit diagram of the q-axis no-load open-circuit transient time constant involved in the embodiments of the present invention;

[0048] Figure 4 This is an equivalent circuit diagram of the q-axis no-load open-circuit subtransient time constant involved in the embodiments of the present invention;

[0049] Figure 5 This is a schematic diagram of the structure of a modeling device for a sixth-order mathematical model of electromechanical transients for distributed synchronous condensers, provided in an embodiment of the present invention. Detailed Implementation

[0050] Many specific details are set forth in the following description to provide a full understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of this application; therefore, this application is not limited to the specific embodiments disclosed below.

[0051] Figure 1 This is a flowchart illustrating a modeling method for a sixth-order mathematical model of electromechanical transients for distributed synchronous condensers, provided by an embodiment of the present invention. The following is a detailed explanation in conjunction with... Figure 1 The method provided in the embodiments of the present invention will be described in detail.

[0052] First, a brief description of the original Park model of the generator is given. The original Park model involves 18 primitive parameters, which are very difficult to obtain. Therefore, power system analysis typically uses a practically simplified model. Depending on the simplification method, the practical model contains 11 or 12 practical parameters. The difference between a dual-shaft excitation generator and a traditional generator lies only in replacing one damping winding with one q-axis excitation winding. The reference directions of various electrical quantities are as follows... Figure 2 As shown.

[0053] Where f: d-axis excitation winding;

[0054] g: q-axis excitation winding;

[0055] D: d-axis damping winding;

[0056] Q: q-axis damping winding;

[0057] d, q, 0: The coordinate system of the three phases a, b, and c of the stator after Park transformation;

[0058] ψ f d-axis excitation winding flux linkage;

[0059] ψ g : q-axis excitation winding flux linkage;

[0060] ψ D d-axis damping winding flux linkage;

[0061] ψ Q : q-axis damping winding flux linkage;

[0062] ψ d : Stator winding d-axis flux linkage;

[0063] ψq : Stator winding q-axis flux linkage

[0064] ψ a、b、c : Stator phase a, b, c winding flux linkage;

[0065] u fd d-axis excitation winding voltage

[0066] u fq : q-axis excitation winding voltage

[0067] u a、b、c Stator phases a, b, and c voltages;

[0068] i a、b、c Stator phases a, b, and c currents;

[0069] i D d-axis damping winding current;

[0070] i Q :q-axis damping winding current;

[0071] exist Figure 2 The reference directions of all electrical quantities in the system meet the following requirements:

[0072] (1) The magnetic flux generated by the positive current in the stator winding of the synchronous condenser is opposite to the positive direction of the magnetic flux (i.e., the positive current generates a negative magnetic flux); the magnetic flux generated by the positive current in each winding of the rotor is in the same direction as the positive magnetic flux (the positive current generates a positive magnetic flux).

[0073] (2) The stator windings follow the generator conventions; the rotor windings follow the motor conventions.

[0074] (3) The q-axis leads the d-axis by 90 degrees.

[0075] (4) The positive direction of the stator winding flux linkage of the generator and the current flowing out of the generator (from the end XYZ to the beginning ABC) conform to the right-hand screw rule.

[0076] Step S101: Obtain the q-axis transient reactance, q-axis secondary reactance, d-axis transient electromotive force, and d-axis secondary transient electromotive force of the dual-axis excitation generator.

[0077] Substituting the q-axis operational reactance into the Park equations of the dual-axis excitation generator, and applying the initial value theorem, the q-axis transient reactance X′ of the dual-axis excitation generator is obtained. q and q-axis secondary electric state reactance X″ q .

[0078] The Parker equation model for a dual-shaft excitation generator is as follows:

[0079]

[0080]

[0081] Among them, X d Equivalent d-inductive reactance of stator winding;

[0082] X q Equivalent q-inductive reactance of stator winding;

[0083] X f d-axis excitation winding inductive reactance;

[0084] X g : q-axis excitation winding inductive reactance;

[0085] X D d-axis damping winding inductive reactance;

[0086] X Q : q-axis damping winding inductive reactance;

[0087] X af Mutual inductance between stator winding and d-axis excitation winding;

[0088] X ag Mutual reactance between stator winding and q-axis excitation winding;

[0089] X aD Mutual inductance between stator winding and d-axis damping winding;

[0090] X aQ Mutual inductance between stator winding and q-axis damping winding;

[0091] X fD Mutual inductance between the d-axis excitation winding and the d-axis damping winding;

[0092] X gQ Mutual inductance between the q-axis excitation winding and the q-axis damping winding;

[0093] U d : Stator winding d-axis voltage;

[0094] i d : Stator winding d-axis current;

[0095] r a Stator winding resistance;

[0096] U q : Stator winding q-axis voltage;

[0097] i q : Stator winding q-axis current;

[0098] r q : Stator winding q-axis resistance;

[0099] i f d-axis excitation winding current;

[0100] r f d-axis excitation winding resistance;

[0101] i g : q-axis excitation winding current;

[0102] r g : Resistance of the q-axis excitation winding;

[0103] U D d-axis damping winding voltage;

[0104] r D d-axis damping winding resistance;

[0105] U Q : q-axis damping winding voltage;

[0106] r Q : q-axis damping winding resistance.

[0107] ω: angular velocity.

[0108] In the expression, d, f, and D represent the d-axis winding, and q, g, and Q represent the q-axis winding. The d-axis state equation of the dual-axis excitation generator is exactly the same as that of a conventional generator. This invention derives the q-axis state equation.

[0109] Due to ωψ q and ωψ d Much greater than pψ d and pψ q Therefore, in the derivation of the practical generator model, the transformer electromotive force of the stator winding was neglected, that is, pψ was assumed to be... d =pψ q =0.

[0110] The Q-axis operational reactance can be defined as follows:

[0111]

[0112] From the last two equations of equation (1), we can obtain

[0113]

[0114] Where p: differential operator

[0115] When the voltage U of the q-axis excitation winding fq =0, when, according to equation (2), we can obtain

[0116]

[0117] Combining (4) and (5), we can obtain

[0118]

[0119] According to equation (1), we can obtain

[0120] ψ q =-X q i q +X ag i g +X aQ i Q (7)

[0121] Substituting (6) and (7) into (3) yields:

[0122]

[0123] From the initial value theorem, we can obtain

[0124]

[0125] When the Q winding is not considered, r Q =∞, substituting into equation (8) yields

[0126]

[0127] From the initial value theorem, we can obtain

[0128]

[0129] Step S102: Based on the Park equation, d-axis transient electromotive force and d-axis subtransient electromotive force, obtain the rotor winding voltage equation, q-axis excitation winding current and q-axis damping winding current.

[0130] Based on the induced electromotive force in the traditional generator model, determine the d-axis transient electromotive force E′. d and the d-axis subtransient electromotive force E″ d The rotor winding voltage equation, q-axis excitation winding current, and q-axis damping winding current are obtained based on the Park equation; the d-axis transient electromotive force E′ is used. d and the d-axis subtransient electromotive force E″ d Replace the q-axis excitation winding flux and q-axis damping winding flux in the q-axis excitation winding current and the q-axis damping winding current to obtain the flux through E′ d and E″ d The currents represent the q-axis excitation winding current and the q-axis damping winding current.

[0131] To incorporate rotor variables to the stator side for analysis and measurement, the following practical variables are introduced.

[0132] T′ q0 and T″ q0 Definition and equivalent circuit, such as Figure 3 , 4As shown.

[0133] Figure 3 In the middle, X g1 For the leakage reactance of the q-axis excitation winding, r g Resistance of the q-axis excitation winding

[0134] Figure 4 In the middle, X Q1 For the leakage reactance of the q-axis damping winding, r Q This is the resistance of the q-axis damping winding.

[0135]

[0136] in:

[0137] T′ q0 : q-axis no-load open-circuit transient time constant;

[0138] T″ q0 : q-axis no-load open-circuit subtransient time constant.

[0139] Referring to the definition of induced electromotive force in the traditional generator model of PSD-BPA, the following practical variables are defined:

[0140]

[0141] in:

[0142] E fq : q-axis excitation winding electromotive force;

[0143] E d d-axis induced electromotive force;

[0144] E′ d d-axis transient induced electromotive force;

[0145] E″ d :d-axis transient induced electromotive force.

[0146] According to equation (1), the rotor winding voltage equation can be obtained as follows:

[0147] pψ g =u fq -r g i (14)

[0148] Multiply both sides of equation (14) by achievable

[0149] T′ q0 pE′ d =E fq +X ag i g (15)

[0150] From the last two equations of equation (1), we can obtain

[0151]

[0152] Right now

[0153]

[0154] To eliminate the flux linkage variable in the equation, the flux linkage ψ can be... g and ψ Q Use E′ d and E″ d It can be expressed as follows. According to equation (13), we can obtain...

[0155]

[0156] Substituting (18) into (17) yields

[0157]

[0158] Step S103: Based on the traditional generator model and the voltage equation of the q-axis rotor winding, obtain the differential equation of the q-axis rotor winding.

[0159] By substituting the basic assumptions of the traditional generator model into the voltage equation of the q-axis rotor winding, the differential equation of the q-axis rotor winding is obtained.

[0160] Referencing the basic assumptions of the traditional generator model in PSD-BPA

[0161]

[0162] Substituting the first equation in (19) and (20) into (15), we can obtain the equation concerning E′. d The differential equation is the differential equation of the q-axis rotor winding.

[0163]

[0164] Step S104: Substitute the q-axis transient reactance and the q-axis secondary reactance into the differential equation of the q-axis rotor winding to obtain the first equation of the q-axis state variables of the dual-axis excitation generator.

[0165] Substituting (9) and (11) into (21) yields

[0166]

[0167] The above equation is the first equation for the q-axis state variables of a dual-shaft excitation generator.

[0168] Step S105: Obtain the voltage equation and resistance of the q-axis damping winding; based on the resistance of the q-axis damping winding and the voltage equation of the q-axis damping winding, obtain the differential equation of the q-axis damping winding.

[0169] Based on the Park equation, the voltage equation for the q-axis damping winding is obtained; based on the q-axis no-load open-circuit transient time constant T′... q0 and the q-axis no-load open-circuit subtransient time constant T″ q0 The resistance of the q-axis damping winding is obtained; substituting the resistance of the q-axis damping winding into the voltage equation of the q-axis damping winding, the differential equation of the q-axis damping winding is obtained. According to equation (1), the voltage equation of the q-axis damping winding can also be obtained as follows.

[0170] pψ Q =-r Q i Q (twenty three)

[0171] From equation (12), we can obtain

[0172]

[0173] Substitute equation (24) into equation (23) and multiply both sides of the equation by . achievable

[0174]

[0175] Substituting the second equation in (20) into (25) yields the equation regarding E″. d The differential equation.

[0176]

[0177] Substituting the second equation in (19) into (26), we get

[0178]

[0179] Step S106: Based on the basic assumptions in the traditional generator model and the differential equation of the q-axis damping winding, obtain the second equation of the q-axis state variables of the dual-axis excitation generator.

[0180] From (20), we can obtain Substituting it into (27) yields

[0181]

[0182] The above equation is the second equation for the q-axis state variables of a dual-shaft excitation generator.

[0183] The first equation and the second equation are combined to generate the q-axis state variable equation of the dual-axis excitation generator.

[0184] Equations (22) and (28) are the state variable equations of the q-axis of the dual-axis excitation generator; the state equations of the d-axis and the rotor motion equations of the dual-axis excitation generator are the same as those of the traditional generator and will not be derived further.

[0185] Specific application examples are as follows:

[0186] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0187] To simplify calculations, simplified assumptions were made regarding the mutual inductance between the d-axis and q-axis windings in both PSD-BPA and PSASP.

[0188] Basic Assumption A: PSD-BPA Assumption

[0189]

[0190] Meanwhile, the definitions of each electrical quantity in PSD-BPA are as follows:

[0191]

[0192]

[0193] Basic Assumption B: PSASP Assumption

[0194]

[0195] Meanwhile, the definitions of each electrical quantity in PSASP are as follows:

[0196]

[0197]

[0198] Example 1:

[0199] The sixth-order practical model of the PSD-BPA dual-axis excitation phase-regulator / generator based on assumption A is as follows:

[0200]

[0201] Example 2:

[0202] The sixth-order practical model of the PSASP dual-axis excitation synchronous condenser / generator based on assumption B is as follows:

[0203]

[0204] In the above formula, X1 is the stator leakage reactance.

[0205] Based on the same inventive concept, this invention also provides a modeling device 500 for a sixth-order mathematical model of electromechanical transients for distributed synchronous condensers, such as... Figure 5 As shown, it includes:

[0206] The parameter acquisition unit 510 is used to acquire the q-axis transient reactance, q-axis secondary reactance, d-axis transient electromotive force, and d-axis secondary transient electromotive force of the dual-axis excitation generator;

[0207] The q-axis rotor winding voltage equation acquisition unit 520 is used to obtain the q-axis rotor winding voltage equation, q-axis excitation winding current, and q-axis damping winding current based on the Park equation, d-axis transient electromotive force, and d-axis subtransient electromotive force of the dual-axis excitation generator.

[0208] The first differential equation acquisition unit 530 is used to obtain the differential equation of the q-axis rotor winding based on the traditional generator model and the voltage equation of the q-axis rotor winding.

[0209] The first equation acquisition unit 540 is used to substitute the q-axis transient reactance and the q-axis secondary reactance into the differential equation of the q-axis rotor winding to obtain the first equation of the q-axis state variables of the dual-axis excitation generator.

[0210] The second differential equation acquisition unit 550 is used to acquire the voltage equation of the q-axis damping winding and the resistance of the q-axis damping winding; based on the resistance of the q-axis damping winding and the voltage equation of the q-axis damping winding, the differential equation of the q-axis damping winding is obtained.

[0211] The second equation acquisition unit 560 is used to obtain the second equation of the q-axis state variables of the dual-axis excitation generator based on the basic assumptions in the traditional generator model and the differential equation of the q-axis damping winding.

[0212] Furthermore, the rotor winding voltage equation acquisition unit includes:

[0213] The electromotive force determination sub-unit is used to determine the d-axis transient electromotive force E′ based on the induced electromotive force in a traditional generator model. d and the d-axis subtransient electromotive force E″ d ;

[0214] The voltage equation acquisition subunit is used to obtain the q-axis rotor winding voltage equation, q-axis excitation winding current, and q-axis damping winding current based on the Park equation.

[0215] The winding current acquisition sub-unit is used to obtain the d-axis transient electromotive force E′. d and the d-axis subtransient electromotive force E″ d Replace the q-axis excitation winding flux and q-axis damping winding flux in the q-axis excitation winding current and the q-axis damping winding current to obtain the flux through E′ d and E″ d The currents represent the q-axis excitation winding current and the q-axis damping winding current.

[0216] Furthermore, it also includes:

[0217] The variable equation generation unit is used to combine the first equation and the second equation to generate the q-axis state variable equation of the dual-axis excitation generator.

[0218] Compared with existing technologies, the modeling method of the present invention based on the sixth-order electromechanical transient practical model of generator / synchronous condenser / motor with dual-axis excitation takes into account the influence of q-axis excitation voltage on the model. It can be directly adopted by large power grid simulation software such as PSD-BPA and PSASP, solving the current problem of the need for practical electromechanical transient models of dual-axis excitation distributed synchronous condensers in simulation analysis.

[0219] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0220] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0221] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0222] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0223] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of the claims of the present invention.

Claims

1. A modeling method for a sixth-order mathematical model of electromechanical transients for distributed synchronous condensers, characterized in that, include: Obtain the q-axis transient reactance, q-axis subtransient reactance, d-axis transient electromotive force, and d-axis subtransient electromotive force of the dual-axis exciter; Based on the Park equation, d-axis transient electromotive force and d-axis subtransient electromotive force of the dual-axis excitation generator, the voltage equation of the q-axis rotor winding, the current of the q-axis excitation winding and the current of the q-axis damping winding are obtained. Based on the traditional generator model and the voltage equation of the q-axis rotor winding, the differential equation of the q-axis rotor winding is obtained; Substituting the q-axis transient reactance and the q-axis subtransient reactance into the differential equation of the q-axis rotor winding, the first equation of the q-axis state variables of the dual-axis excitation generator is obtained; Obtain the voltage equation and resistance of the q-axis damping winding; based on the resistance of the q-axis damping winding and the voltage equation of the q-axis damping winding, obtain the differential equation of the q-axis damping winding; Based on the fundamental assumptions in the traditional generator model and the differential equation of the q-axis damping winding, the second equation for the q-axis state variables of the dual-axis excitation generator is obtained.

2. The method according to claim 1, characterized in that, The q-axis transient reactance and q-axis subtransient reactance of the dual-axis excitation generator are obtained based on the Park equation and the q-axis operational reactance of the dual-axis excitation generator, specifically including: By transforming the Park equations for the dual-shaft excitation generator and substituting them into the q-axis operational reactance, the q-axis transient reactance of the dual-shaft excitation generator can be obtained according to the initial value theorem. and q-axis subtransient reactance .

3. The method according to claim 1, characterized in that, Based on the Park equations, d-axis transient electromotive force, and d-axis subtransient electromotive force of the dual-shaft excitation generator, the voltage equations for the q-axis rotor windings, as well as the currents for the q-axis excitation windings and damping windings, are obtained, including: Determine the d-axis transient electromotive force based on the induced electromotive force in the traditional generator model. and d-axis subtransient electromotive force ; The q-axis rotor winding voltage equation, q-axis excitation winding current, and q-axis damping winding current are obtained based on the Park equation. Using the d-axis transient electromotive force and d-axis subtransient electromotive force Replacing the q-axis excitation winding flux and q-axis damping winding flux in the q-axis excitation winding current and the q-axis damping winding current, obtains... and The currents represent the q-axis excitation winding current and the q-axis damping winding current.

4. The method according to claim 1, characterized in that, Based on the traditional generator model and the voltage equation of the q-axis rotor winding, the differential equation of the q-axis rotor winding is obtained, including: By substituting the basic assumptions of the traditional generator model and the q-axis excitation winding current into the q-axis rotor winding voltage equation, the differential equation of the q-axis rotor winding is obtained.

5. The method according to claim 1, characterized in that, Based on the resistance and voltage equations of the q-axis damping winding, the differential equations of the q-axis damping winding are obtained, including: Based on the Park equation, the voltage equation for the q-axis damping winding is obtained; Based on the q-axis no-load open-circuit transient time constant and q-axis no-load open-circuit subtransient time constant To obtain the resistance of the q-axis damping winding; Substituting the resistance of the q-axis damping winding into the voltage equation of the q-axis damping winding, we obtain the differential equation of the q-axis damping winding.

6. The method according to claim 1, characterized in that, Based on the fundamental assumptions of the traditional generator model and the differential equation of the q-axis damping winding, the second equation for the q-axis state variables of the dual-axis excitation generator is obtained, including: Substituting the basic assumptions of the traditional generator model into the differential equation of the q-axis damping winding, we obtain the second equation for obtaining the q-axis state variables of the dual-axis excitation generator.

7. The method according to claim 1, characterized in that, Also includes: The first equation and the second equation are combined to generate the q-axis state variable equation of the dual-axis excitation generator.

8. A modeling device for a sixth-order mathematical model of electromechanical transients for distributed synchronous condensers, characterized in that, include: The parameter acquisition unit is used to acquire the q-axis transient reactance, q-axis subtransient reactance, d-axis transient electromotive force, and d-axis subtransient electromotive force of the dual-axis excitation generator. The q-axis rotor winding voltage equation acquisition unit is used to obtain the q-axis rotor winding voltage equation, q-axis excitation winding current, and q-axis damping winding current based on the Park equation, d-axis transient electromotive force, and d-axis subtransient electromotive force of the dual-axis excitation generator. The first differential equation acquisition unit is used to obtain the differential equation of the q-axis rotor winding based on the traditional generator model and the voltage equation of the q-axis rotor winding. The first equation acquisition unit is used to substitute the q-axis transient reactance and the q-axis subtransient reactance into the differential equation of the q-axis rotor winding to obtain the first equation of the q-axis state variables of the dual-axis excitation generator. The second differential equation acquisition unit is used to acquire the voltage equation of the q-axis damping winding and the resistance of the q-axis damping winding; based on the resistance of the q-axis damping winding and the voltage equation of the q-axis damping winding, the differential equation of the q-axis damping winding is obtained. The second equation acquisition unit is used to obtain the second equation of the q-axis state variables of the dual-axis excitation generator based on the basic assumptions in the traditional generator model and the differential equation of the q-axis damping winding.

9. The apparatus according to claim 8, characterized in that, The rotor winding voltage equation acquisition unit includes: The electromotive force determination sub-unit is used to determine the d-axis transient electromotive force based on the induced electromotive force in a traditional generator model. and d-axis subtransient electromotive force ; The voltage equation acquisition subunit is used to obtain the rotor winding voltage equation, q-axis excitation winding current and q-axis damping winding current according to the Park equation. The winding current acquisition sub-unit is used to obtain the d-axis transient electromotive force. and d-axis subtransient electromotive force Replacing the q-axis excitation winding flux and q-axis damping winding flux in the q-axis excitation winding current and the q-axis damping winding current, obtains... and The currents represent the q-axis excitation winding current and the q-axis damping winding current.

10. The apparatus according to claim 8, characterized in that, Also includes: The variable equation generation unit is used to combine the first equation and the second equation to generate the q-axis state variable equation of the dual-axis excitation generator.

11. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 7.

12. A readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 7.

Images