Harmonic impedance determination method, determination apparatus and electronic device

Abstract

The application provides a harmonic impedance determination method, a determination device and electronic equipment. The method comprises the following steps: obtaining initial operation parameters of a synchronous generator set; obtaining excitation system parameters in the synchronous generator set, generating an excitation voltage model according to the initial operation parameters and the excitation system parameters, and determining an excitation voltage through the excitation voltage model; obtaining shafting parameters in the synchronous generator set, generating an electromagnetic torque model according to the shafting parameters, and determining an electromagnetic torque through the electromagnetic torque model; obtaining synchronous motor parameters in the synchronous generator set, generating a harmonic impedance model according to the excitation voltage, the electromagnetic torque and the synchronous motor parameters, and determining a harmonic impedance through the harmonic impedance model, so as to perform harmonic flow and harmonic stability analysis on a power system in which the synchronous generator set is located. Through the application, the problem of inaccurate harmonic impedance calculation in the prior art is solved.

Description

Technical Field

[0001] This application relates to the field of synchronous motors, and more specifically, to a method, apparatus, computer-readable storage medium, and electronic device for determining harmonic impedance. Background Technology

[0002] With the increasing electrification of power sources, grids, and loads in power systems, the number of power electronic devices (such as new energy generating units and FACTS devices) is growing. Due to the interaction between the multi-timescale controllers of these power electronic devices and the shaft systems, windings, and control dynamics of synchronous generators, the shaft systems, windings, and control dynamics of synchronous generators may have a significant impact on the harmonic power flow and harmonic resonance of power systems with a high proportion of power electronic components. However, in traditional power system harmonic power flow and harmonic resonance calculation software, the harmonic impedance characteristics of synchronous generators are generally approximated by their negative-sequence reactance, without considering the influence of the shaft systems, windings, and control dynamics of the synchronous generators.

[0003] Therefore, determining the harmonic impedance characteristics of a high-proportion power system while considering the influence of synchronous generator shafts, windings, and their control dynamics is a problem that urgently needs to be solved. Summary of the Invention

[0004] The main objective of this application is to provide a method, apparatus, computer-readable storage medium, and electronic device for determining harmonic impedance, so as to at least solve the problem of inaccurate harmonic impedance calculation in the prior art.

[0005] To achieve the above objectives, according to one aspect of this application, a method for determining harmonic impedance is provided, comprising: obtaining initial operating parameters of a synchronous generator set, wherein the synchronous generator set includes at least a synchronous motor, an excitation system, a shaft system, and a prime mover speed control system, and the initial operating parameters include at least the power angle of the synchronous motor; obtaining excitation system parameters in the synchronous generator set, generating an excitation voltage model based on the initial operating parameters and the excitation system parameters, and determining the excitation voltage through the excitation voltage model; obtaining shaft system parameters in the synchronous generator set, generating an electromagnetic torque model based on the shaft system parameters, and determining the electromagnetic torque through the electromagnetic torque model; obtaining synchronous motor parameters in the synchronous generator set, generating a harmonic impedance model based on the excitation voltage, the electromagnetic torque, and the synchronous motor parameters, and determining the harmonic impedance through the harmonic impedance model, so as to perform harmonic power flow and harmonic stability analysis on the power system in which the synchronous generator set is located.

[0006] Optionally, generating an excitation voltage model based on the initial operating parameters and the excitation system parameters includes: generating a first transfer function based on the excitation system parameters. The excitation system is controlled by negative feedback control, G v (f) represents the first transfer function, f represents the harmonic frequency, and T R K represents the time constant of the filter, and K represents the gain of the voltage regulator. V This represents the proportional-integral adjustment factor, T1, T2, T3, and T4 are the time constants of the voltage regulator, and K is the proportional-integral adjustment factor. A T is the gain of the voltage regulator. A K represents the time constant of the amplifier in the voltage regulator. F T is the steady-state loop gain of the voltage regulator. F The steady-state loop time constant of the voltage regulator is defined; the filter and the voltage regulator are included in the excitation system; the amplifier is included in the voltage regulator; a second transfer function is generated based on the first transfer function and the initial operating parameters. in, The second transfer function is represented by δ0, where δ0 represents the initial power angle of the synchronous generator set, V0 is the initial voltage amplitude of the synchronous motor, and u d0 u represents the initial component of the direct-axis voltage of the synchronous motor. q0 The initial component of the quadrature-axis voltage of the synchronous motor is represented; the excitation voltage model is generated based on the second transfer function. Among them, E f (f) represents the excitation voltage, u d u represents the direct-axis voltage component of the synchronous motor. q This represents the quadrature-axis voltage component of the synchronous motor.

[0007] Optionally, generating an electromagnetic torque model based on the shaft system parameters includes: generating an initial electromagnetic torque model based on the shaft system parameters; and generating the electromagnetic torque model-T based on the initial electromagnetic torque model. e (f)=J eq (f)ω(f), where J eq (f) represents the initial electromagnetic torque model, ω(f) represents the rotational speed of the synchronous motor, and f represents the harmonic frequency.

[0008] Optionally, an initial electromagnetic torque model is generated. in,

[0009] T J1 T represents the inertial time constant of the mass in a high-pressure cylinder. J2 T represents the inertial time constant of mass A in the low-pressure cylinder. J3 T represents the inertial time constant of mass B in the low-pressure cylinder. J4K represents the inertial time constant of the generator mass. 12 K represents the stiffness coefficient of the axial segment between the high-pressure cylinder block and the low-pressure cylinder block A. 23 K represents the stiffness coefficient of the axial segment between the low-pressure cylinder A block and the low-pressure cylinder B block. 34 D1 represents the stiffness coefficient of the shaft segment between the low-pressure cylinder B mass block and the synchronous motor mass block; D2 represents the mechanical damping coefficient of the high-pressure cylinder A mass block; D3 represents the mechanical damping coefficient of the low-pressure cylinder B mass block; D4 represents the mechanical damping coefficient of the mass block; and the mass block represents a component module with mass in the shaft system. b This indicates the rated frequency of the synchronous generator set. Indicates taking the matrix The third element, ω B Indicates the rated angular frequency.

[0010] Optionally, generating a harmonic impedance model based on the excitation voltage, the electromagnetic torque, and the synchronous motor parameters includes: generating an initial harmonic impedance model based on the excitation voltage, the electromagnetic torque, and the synchronous motor parameters; and generating the harmonic impedance model based on the initial harmonic impedance model. in, Let f represent the initial harmonic impedance model, and f represent the harmonic frequency. b This indicates the rated frequency of the synchronous motor.

[0011] Optionally, generating an initial harmonic impedance model based on the excitation voltage, the electromagnetic torque, and the synchronous motor parameters includes: generating an initial harmonic impedance model based on the excitation voltage, the electromagnetic torque, and the synchronous motor parameters.

[0012] in,

[0013] S b U represents the rated apparent power of the synchronous motor. b The rated line voltage r of the synchronous motor is indicated. a x represents the stator resistance of the synchronous motor. l x represents the stator leakage reactance of the synchronous motor. d x' represents the direct-axis synchronous reactance of the synchronous motor. d x″ represents the direct-axis transient reactance of the synchronous motor. dx represents the direct-axis subtransient reactance of the synchronous motor. q x' represents the quadrature-axis synchronous reactance of the synchronous motor. q x″ represents the quadrature-axis transient reactance of the synchronous motor. q T' represents the quadrature-axis subtransient reactance of the synchronous motor. d0 T″ represents the direct-axis transient open-circuit time constant of the synchronous motor. d0 T' represents the direct-axis subtransient open-circuit time constant of the synchronous motor. q0 T″ represents the quadrature-axis transient open-circuit time constant of the synchronous motor. q0 This represents the quadrature-axis subtransient open-circuit time constant of the synchronous motor.

[0014] Optionally, determining the harmonic impedance using the harmonic impedance model includes: when the absolute value of the harmonic frequency is less than a preset frequency, the harmonic impedance is a two-dimensional matrix. Where Z(f) represents the one-dimensional or two-dimensional harmonic impedance; when the absolute value of the harmonic frequency is greater than a preset frequency, the harmonic impedance is a one-dimensional complex number. in, This represents the elements in the first row and first column of the harmonic impedance model.

[0015] According to another aspect of this application, a device for determining harmonic impedance is provided, comprising: an acquisition unit for acquiring initial operating parameters of a synchronous generator set, wherein the synchronous generator set includes at least a synchronous motor, an excitation system, a shaft system, and a prime mover speed control system, and the initial operating parameters include at least the power angle of the synchronous motor; a first determination unit for acquiring excitation system parameters in the synchronous generator set, generating an excitation voltage model based on the initial operating parameters and the excitation system parameters, and determining the excitation voltage through the excitation voltage model; a second determination unit for acquiring shaft system parameters in the synchronous generator set, generating an electromagnetic torque model based on the shaft system parameters, and determining the electromagnetic torque through the electromagnetic torque model; and a third determination unit for acquiring synchronous motor parameters in the synchronous generator set, generating a harmonic impedance model based on the excitation voltage, the electromagnetic torque, and the synchronous motor parameters, and determining the harmonic impedance through the harmonic impedance model, so as to perform harmonic power flow and harmonic stability analysis on the power system in which the synchronous generator set is located.

[0016] According to another aspect of this application, a computer-readable storage medium is provided, the computer-readable storage medium including a stored program, wherein, when the program is executed, it controls the device where the computer-readable storage medium is located to perform any of the determination methods described above.

[0017] According to another aspect of this application, an electronic device is provided, comprising: one or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the one or more programs including methods for performing any of the aforementioned determining methods.

[0018] By applying the technical solution of this application, the initial operating parameters and excitation system parameters of the synchronous generator set are obtained, an excitation voltage model is generated, an electromagnetic torque model is generated based on the shaft system parameters, and a harmonic impedance model is generated based on the excitation voltage, the electromagnetic torque, and the synchronous generator parameters. The harmonic impedance is then determined using the harmonic impedance model. Compared with existing technologies that fail to consider the influence of the synchronous generator set's shaft system, windings, and control dynamics when determining harmonic impedance, leading to inaccurate harmonic impedance calculations, this application can obtain more accurate harmonic impedance based on the synchronous generator set's shaft system and winding parameters. This allows for precise analysis of power system harmonic flow and harmonic stability. Therefore, it solves the problem of inaccurate power system harmonic flow and harmonic stability calculations caused by inaccurate harmonic impedance calculations in existing technologies, achieving accurate determination of harmonic impedance and thus enabling more precise analysis of power system harmonic flow and harmonic stability characteristics. Attached Figure Description

[0019] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0020] Figure 1 A hardware structure block diagram of a mobile terminal for performing a method for determining harmonic impedance according to an embodiment of this application is shown.

[0021] Figure 2 A schematic flowchart illustrating a method for determining harmonic impedance provided in an embodiment of this application is shown.

[0022] Figure 3 A schematic diagram of the structure of a synchronous generator set in a specific method for determining harmonic impedance provided in an embodiment of this application is shown.

[0023] Figure 4 The diagram shows a negative feedback control flowchart of the excitation system in a specific method for determining harmonic impedance provided in an embodiment of this application.

[0024] Figure 5 A schematic diagram of the shaft system structure in a specific method for determining harmonic impedance provided in an embodiment of this application is shown;

[0025] Figure 6A structural block diagram of a harmonic impedance determination device provided by an embodiment of this application is shown.

[0026] The above figures include the following reference numerals:

[0027] 102. Processor; 104. Memory; 106. Transmission device; 108. Input / output device. Detailed Implementation

[0028] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0029] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0030] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this application described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0031] For ease of description, the following explains some of the nouns or terms used in the embodiments of this application:

[0032] Harmonics: Harmonics refer to the components of a periodic non-sinusoidal alternating current quantity that are integer multiples of the fundamental frequency, obtained by Fourier series decomposition. These are usually called higher harmonics, while the fundamental frequency refers to the component whose frequency is the same as the power frequency (50Hz). Interference from higher harmonics is a major "public nuisance" affecting power quality in current power systems.

[0033] Impedance: In a circuit with inductance, capacitance and resistance, the resistance that impedes the flow of current in the circuit is called impedance.

[0034] As described in the background section, the prior art does not consider the influence of parameters such as the shaft system and windings of the synchronous generator when calculating harmonic impedance, resulting in inaccurate harmonic impedance calculation. To solve the problem of inaccurate harmonic impedance calculation, the embodiments of this application provide a method, apparatus, computer-readable storage medium, and electronic device for determining harmonic impedance.

[0035] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0036] The methods and embodiments provided in this application can be executed on a mobile terminal, computer terminal, or similar computing device. Taking running on a mobile terminal as an example, Figure 1 This is a hardware structure block diagram of a mobile terminal for a method of determining harmonic impedance according to an embodiment of the present invention. Figure 1 As shown, a mobile terminal may include one or more ( Figure 1 Only one is shown in the diagram. A processor 102 (which may include, but is not limited to, a microprocessor MCU or a programmable logic device FPGA, etc.) and a memory 104 for storing data are also shown. The mobile terminal may further include a transmission device 106 for communication functions and an input / output device 108. Those skilled in the art will understand that... Figure 1 The structure shown is for illustrative purposes only and does not limit the structure of the mobile terminal described above. For example, the mobile terminal may also include components that are more... Figure 1 The more or fewer components shown, or having the same Figure 1 The different configurations shown.

[0037] The memory 104 can be used to store computer programs, such as application software programs and modules, like the computer program corresponding to the method for determining harmonic impedance in this embodiment of the invention. The processor 102 executes various functional applications and data processing by running the computer program stored in the memory 104, thereby implementing the above-described method. The memory 104 may include high-speed random access memory and may also include non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memory. In some instances, the memory 104 may further include memory remotely located relative to the processor 102, and these remote memories can be connected to the mobile terminal via a network. Examples of the aforementioned networks include, but are not limited to, the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof. The transmission device 106 is used to receive or send data via a network. Specific examples of the aforementioned networks may include wireless networks provided by the mobile terminal's communication provider. In one example, the transmission device 106 includes a network interface controller (NIC), which can be connected to other network devices via a base station to communicate with the Internet. In one example, the transmission device 106 may be a radio frequency (RF) module, which is used to communicate with the Internet wirelessly.

[0038] This embodiment provides a method for determining the harmonic impedance of a mobile terminal, computer terminal, or similar computing device. It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. Although a logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in a different order than that shown here.

[0039] Figure 2 This is a flowchart of a method for determining harmonic impedance according to an embodiment of this application. Figure 2 As shown, the method includes the following steps:

[0040] Step S201: Obtain the initial operating parameters of the synchronous generator set, wherein the synchronous generator set includes at least a synchronous motor, an excitation system, a shaft system and a prime mover speed control system, and the initial operating parameters include at least the power angle of the synchronous motor;

[0041] Specifically, this application establishes a calculation model for harmonic impedance considering the influence of shaft system parameters of the synchronous generator set. It mainly considers the synchronous motor, excitation system, shaft system, and prime mover speed control system within the synchronous generator set. First, initial operating parameters are obtained, including the power angle δ0 of the synchronous generator set, the voltage amplitude V0 of the synchronous motor, and the direct-axis component u of the synchronous motor voltage. d0The quadrature axis component u of the synchronous motor voltage q0 The direct-axis component i of the synchronous motor current d0 The quadrature axis component i of the synchronous motor current q0 The direct-axis component of the subtransient electromotive force E″ d0 The quadrature component of the subtransient electromotive force E″ q0 .

[0042] Step S202: Obtain the excitation system parameters in the synchronous generator set, generate an excitation voltage model based on the initial operating parameters and excitation system parameters, and determine the excitation voltage through the excitation voltage model;

[0043] Specifically, after obtaining the initial operating parameters, the excitation system parameters are obtained, including: the time constant of the filter, the gain of the voltage regulator, the proportional-integral adjustment factor, the time constant of the voltage regulator, the gain of the voltage regulator, the time constant of the amplifier in the voltage regulator, the gain of the steady loop of the voltage regulator, the time constant of the steady loop of the voltage regulator, etc. Based on the initial operating parameters and the excitation system parameters, the excitation voltage model can be established and the excitation voltage can be determined.

[0044] Step S203: Obtain the shaft system parameters in the synchronous generator set, generate an electromagnetic torque model based on the shaft system parameters, and determine the electromagnetic torque through the electromagnetic torque model;

[0045] Specifically, the shaft system parameters are obtained, including: the inertia time constant of the high-pressure cylinder mass, the inertia time constant of the low-pressure cylinder A mass, the inertia time constant of the low-pressure cylinder B mass, the inertia time constant of the generator mass, the stiffness coefficient of the shaft segment between the high-pressure cylinder mass and the low-pressure cylinder A mass, and the rated frequency, etc. An electromagnetic torque model is established based on the shaft system parameters and the electromagnetic torque is calculated.

[0046] Step S204: Obtain the synchronous motor parameters in the synchronous generator set, generate a harmonic impedance model based on the excitation voltage, electromagnetic torque and synchronous motor parameters, determine the harmonic impedance through the harmonic impedance model, and perform harmonic power flow and harmonic stability analysis on the power system where the synchronous generator set is located.

[0047] Specifically, synchronous motor parameters are obtained, and a harmonic impedance model is generated based on the excitation voltage, electromagnetic torque, and synchronous motor parameters. The harmonic impedance is then determined, and the harmonic impedance characteristics of the synchronous unit are accurately simulated while considering the influence of shaft system, windings, etc. This allows for a more precise analysis of the harmonic power flow and harmonic stability characteristics of the power system, and better guidance for the safe and stable operation of the power system.

[0048] This embodiment obtains the initial operating parameters and excitation system parameters of the synchronous generator set, generates an excitation voltage model, generates an electromagnetic torque model based on the shaft system parameters, and generates a harmonic impedance model based on the excitation voltage, electromagnetic torque, and synchronous generator parameters. The harmonic impedance is then determined using this model. Compared to existing technologies that fail to consider the influence of the synchronous generator set's shaft system, windings, and control dynamics when determining harmonic impedance, leading to inaccurate harmonic impedance calculations, this application can obtain more accurate harmonic impedance based on the synchronous generator set's shaft system and winding parameters. This allows for precise analysis of the harmonic power flow and harmonic stability characteristics of the power system, better guiding the safe and stable operation of the power system. Therefore, it solves the problem of inaccurate harmonic impedance calculations in existing technologies, leading to inaccurate calculations of power system harmonic power flow and harmonic stability. This achieves accurate determination of harmonic impedance, thereby enabling precise analysis of the power system's harmonic power flow and harmonic stability characteristics, and better guiding the safe and stable operation of the power system.

[0049] In specific implementation, step S202 above can be achieved through the following steps: generating a first transfer function based on the excitation system parameters. The excitation system is controlled by negative feedback control, G v (f) represents the first transfer function, f represents the harmonic frequency, and T R K represents the time constant of the filter, and K represents the gain of the voltage regulator. V This represents the proportional-integral (PI) adjustment factor, where T1, T2, T3, and T4 are the time constants of the voltage regulator, and K is the input voltage regulator ... A T is the gain of the voltage regulator. A K represents the time constant of the amplifier in the voltage regulator. F T is the gain of the steady-state loop of the voltage regulator. F The steady-state loop time constant of the voltage regulator is defined; the filter and voltage regulator are included in the excitation system, and the amplifier is included in the voltage regulator; a second transfer function is generated based on the first transfer function and the initial operating parameters. in, This represents the second transfer function, δ0 represents the initial power angle of the synchronous generator set, V0 is the initial voltage amplitude of the synchronous motor, and u d0 u represents the initial component of the direct-axis voltage of the synchronous motor. q0 Represents the initial component of the quadrature-axis voltage of the synchronous motor; generates the excitation voltage model based on the second transfer function. Among them, u d u represents the direct-axis voltage component of a synchronous motor. q This represents the quadrature-axis voltage component of the synchronous motor. This method calculates the transfer function of the excitation system, allowing the generation of a computational model for the excitation voltage based on the transfer function.

[0050] Specifically, there are various models for the excitation system of synchronous generator units. The commonly used model is the FV-type excitation system model, where the ratio of generator terminal voltage to generator frequency (V / F) is within a certain operating range during normal generator operation. The excitation system uses negative feedback control; therefore, the excitation system can be represented using a negative feedback control block diagram from automatic control principles. Then, the transfer function of the excitation system is calculated based on the negative feedback control system. Therefore, the excitation system parameters are first obtained, including: the time constant of the filter, the gain of the voltage regulator, the proportional-integral adjustment factor, the time constant of the voltage regulator, the gain of the voltage regulator, the time constant of the amplifier in the voltage regulator, the gain of the voltage regulator's steady-state loop, and the time constant of the voltage regulator's steady-state loop. The harmonic frequencies also need to be obtained. A first transfer function is generated based on these parameters. The first transfer function is multiplied by the initial operating parameters to obtain a second transfer function. The second transfer function is then multiplied by the direct-axis and quadrature-axis components of the synchronous generator voltage to obtain the final excitation system voltage model, and the excitation voltage is calculated.

[0051] To accurately calculate the electromagnetic torque, step S203 of this application can be achieved through the following steps: generating an initial electromagnetic torque model based on the shaft system parameters; generating an electromagnetic torque model-T based on the initial electromagnetic torque model. e (f)=J eq (f)ω(f), where J eq (f) represents the initial electromagnetic torque model, ω(f) represents the speed of the synchronous motor, and f represents the harmonic frequency.

[0052] Specifically, the shaft system refers to the transmission system in a propulsion device, consisting mainly of drive shafts, from the main engine output shaft flange to the propeller. Therefore, the shaft system exhibits electromagnetic torque, which is a crucial parameter of synchronous generator sets. The process begins by obtaining the shaft system parameters, generating an electromagnetic torque calculation model based on these parameters, and then calculating the electromagnetic torque.

[0053] Step S203 above also includes the following step: generating an initial electromagnetic torque model. in,

[0054] T J1 T represents the inertial time constant of the mass in a high-pressure cylinder. J2 T represents the inertial time constant of mass A in the low-pressure cylinder. J3 T represents the inertial time constant of mass B in the low-pressure cylinder. J4 K represents the inertial time constant of the generator mass. 12 K represents the stiffness coefficient of the shaft segment between the high-pressure cylinder mass block and the low-pressure cylinder mass block A. 23 K represents the stiffness coefficient of the shaft segment between low-pressure cylinder block A and low-pressure cylinder block B.34 D1 represents the stiffness coefficient of the shaft segment between the low-pressure cylinder B mass and the synchronous motor mass; D2 represents the mechanical damping coefficient of the high-pressure cylinder mass; D3 represents the mechanical damping coefficient of the low-pressure cylinder A mass; D4 represents the mechanical damping coefficient of the synchronous motor mass; and a mass represents a component module with mass in the shaft system. b Indicates the rated frequency of the synchronous generator set. Indicates taking the matrix The third element, ω B Indicates the rated angular frequency.

[0055] Specifically, the shaft system includes the high-pressure cylinder mass block, the low-pressure cylinder A mass block, the low-pressure cylinder B mass block, and the generator mass block. The shaft system parameters include: the inertia time constant of the high-pressure cylinder mass block, the inertia time constant of the low-pressure cylinder A mass block, the inertia time constant of the low-pressure cylinder B mass block, the inertia time constant of the generator mass block, the stiffness coefficient of the shaft segment between the high-pressure cylinder mass block and the low-pressure cylinder A mass block, the stiffness coefficient of the shaft segment between the low-pressure cylinder A mass block and the low-pressure cylinder B mass block, the stiffness coefficient of the shaft segment between the low-pressure cylinder B mass block and the synchronous motor mass block, the mechanical damping coefficient of the high-pressure cylinder mass block, the mechanical damping coefficient of the low-pressure cylinder A mass block, the mechanical damping coefficient of the low-pressure cylinder B mass block, and the mechanical damping coefficient of the synchronous motor mass block. It is also necessary to obtain the rated frequency and rated angular frequency of the synchronous generator set, and then generate an initial electromagnetic torque model based on the above parameters.

[0056] In some embodiments, step S203 can be specifically implemented through the following steps: generating an initial harmonic impedance model based on the excitation voltage, electromagnetic torque, and synchronous motor parameters; generating a harmonic impedance model based on the initial harmonic impedance model. in, This represents the initial harmonic impedance model. This method generates an initial harmonic impedance calculation model based on the excitation voltage and electromagnetic torque, which can accurately calculate the harmonic impedance.

[0057] Specifically, after calculating the excitation voltage and electromagnetic torque as described above, an initial harmonic impedance calculation model is generated based on the relationship between the excitation voltage and electromagnetic torque and the harmonic impedance, so as to ensure that the harmonic impedance is accurately calculated in the subsequent process.

[0058] To further accurately calculate the harmonic impedance, in some embodiments, step S203 above can be specifically implemented through the following steps: generating an initial harmonic impedance model based on the excitation voltage, electromagnetic torque, and synchronous motor parameters. in,

[0059] S b U represents the rated apparent power of the synchronous motor. b f represents the rated line voltage of the synchronous motor. b The rated frequency of the synchronous motor is represented by r. a x represents the stator resistance of a synchronous motor. l The stator leakage reactance of a synchronous motor, x d x' represents the direct-axis synchronous reactance of a synchronous motor. d x″ represents the direct-axis transient reactance of a synchronous motor. d x represents the direct-axis subtransient reactance of a synchronous motor. q x' represents the quadrature-axis synchronous reactance of a synchronous motor. q x″ represents the quadrature-axis transient reactance of a synchronous motor. q T′ represents the quadrature-axis subtransient reactance of a synchronous motor. d0 T″ represents the direct-axis transient open-circuit time constant of a synchronous motor. d0 T′ represents the direct-axis subtransient open-circuit time constant of a synchronous motor. q0 T″ represents the quadrature-axis transient open-circuit time constant of a synchronous motor. q0 This represents the quadrature-axis subtransient open-circuit time constant of a synchronous motor.

[0060] Specifically, the synchronous motor parameters include: the rated apparent power of the synchronous motor, the rated line voltage of the synchronous motor, the rated frequency of the synchronous motor, the stator resistance of the synchronous motor, the stator leakage reactance of the synchronous motor, the direct-axis synchronous reactance of the synchronous motor, the direct-axis transient reactance of the synchronous motor, the direct-axis subtransient reactance of the synchronous motor, the quadrature-axis synchronous reactance of the synchronous motor, the quadrature-axis transient reactance of the synchronous motor, the quadrature-axis subtransient reactance of the synchronous motor, the direct-axis transient open-circuit time constant of the synchronous motor, the direct-axis subtransient open-circuit time constant of the synchronous motor, the quadrature-axis transient open-circuit time constant of the synchronous motor, and the quadrature-axis subtransient open-circuit time constant of the synchronous motor. Based on the above synchronous motor parameters, excitation voltage, and electromagnetic torque, a harmonic impedance calculation model is generated, and the harmonic impedance is calculated.

[0061] To determine the harmonic impedance at different operating frequencies, in some embodiments, step S203 can be specifically implemented through the following steps: when the absolute value of the harmonic frequency is less than a preset frequency, the harmonic impedance is a two-dimensional matrix. Where f represents the harmonic frequency; when the absolute value of the harmonic frequency is greater than the preset frequency, the harmonic impedance is a one-dimensional complex number.

[0062] Specifically, the harmonic impedance characteristics of the synchronous generator set at the operating frequency f are simulated in the power system harmonic power flow or harmonic resonance calculation software based on the magnitude of the operating frequency f. A preset frequency of 100Hz is selected. When the absolute value of the selected operating frequency f is less than 100Hz, the harmonic impedance characteristic Z(f) of the synchronous generator set is simulated as a 2*2 matrix in the power system harmonic power flow or harmonic resonance calculation software. When the absolute value of the selected operating frequency f is greater than 100Hz, the harmonic impedance characteristic Z(f) of the synchronous generator set is simulated as a one-dimensional complex number in the power system harmonic power flow or harmonic resonance calculation software.

[0063] To enable those skilled in the art to better understand the technical solution of this application, the implementation process of the method for determining harmonic impedance of this application will be described in detail below with reference to specific embodiments.

[0064] This embodiment relates to a specific method for determining harmonic impedance, such as... Figures 3 to 5 As shown, it includes the following steps:

[0065] Step S1: The structural schematic diagram of the synchronous generator set of this application is shown below. Figure 3 As shown, it includes an excitation system, shaft system, synchronous motor and prime mover, and speed control system. The synchronous motor and excitation system are connected to a step-up transformer, which is connected to the power grid. abc i represents the three-phase voltage of the synchronous motor. abc V represents the three-phase current of the synchronous motor, and E represents the voltage amplitude of the synchronous motor. f Indicates the excitation voltage, i f T represents the excitation current. e T represents electromagnetic torque. m P represents mechanical torque. e ω represents electromagnetic power, and ω represents the rotor speed of the synchronous motor;

[0066] Step S2: Obtain the initial operating parameters of the synchronous generator set through numerical simulation or measurement, including the power angle δ0 of the synchronous generator set, the electromechanical voltage amplitude V0, and the direct-axis component u of the terminal voltage. d0 The quadrature axis component u of the terminal voltage q0 The direct-axis component i of the terminal current d0 The quadrature axis component i of the terminal current q0 The direct-axis component of the subtransient electromotive force E″ d0 The quadrature component of the subtransient electromotive force E″ q0 ;

[0067] Step S3: Obtain excitation system parameters, and based on these parameters, generate the excitation voltage E at frequency f in the power system harmonic flow or harmonic resonance calculation software. fThe direct-axis voltage component u of the synchronous motor d The quadrature axis component of the voltage of a synchronous motor, u q The calculation relationship, and the flowchart of the negative feedback control of the excitation system are as follows: Figure 4 As shown, the transfer function is as follows: G v As shown in (f):

[0068]

[0069]

[0070]

[0071] in, This represents the second transfer function. Figure 4 In this context, s is a complex frequency domain variable, and its relationship with frequency domain f is s = j2πf, i.e. Figure 4 The other formulas are similar, where δ0 represents the initial power angle of the synchronous generator set, V0 is the initial voltage amplitude of the synchronous motor, and u d0 u represents the initial component of the direct-axis voltage of the synchronous motor. q0 E represents the initial component of the quadrature-axis voltage of a synchronous motor. f (f) represents the excitation voltage, u d u represents the direct-axis voltage component of a synchronous motor. q G represents the quadrature-axis voltage component of a synchronous motor. v (f) represents the first transfer function, f represents the harmonic frequency, and T R K represents the time constant of the filter, and K represents the gain of the voltage regulator. V This represents the proportional-integral (PI) adjustment factor, where T1, T2, T3, and T4 are the time constants of the voltage regulator, and K is the input voltage regulator ... A T is the gain of the voltage regulator. A K represents the time constant of the amplifier in the voltage regulator. F T is the gain of the steady-state loop of the voltage regulator. F The steady-state loop time constant of the voltage regulator is defined. The filter and voltage regulator are included in the excitation system, and the amplifier is included in the voltage regulator.

[0072] Step S4: Obtain shaft system parameters, the shaft system includes the high and medium pressure cylinder mass T m1 Low-pressure cylinder A mass T m2 Low-pressure cylinder B mass T m3 and generator mass T e ,like Figure 5 As shown, the electromagnetic torque T at frequency f is generated in power system harmonic power flow or harmonic resonance calculation software based on shaft parameters. e The relationship between the synchronous generator speed ω and the calculation of the synchronous generator speed:

[0073] -T e (f)=J eq (f)ω(f)

[0074]

[0075]

[0076] Among them, T e (f) represents the electromagnetic torque, J eq (f) represents the initial electromagnetic torque model, ω(f) represents the synchronous motor speed, f represents the harmonic frequency, and J eq (f) represents the electromagnetic torque, T J1 T represents the inertial time constant of the mass in a high-pressure cylinder. J2 T represents the inertial time constant of mass A in the low-pressure cylinder. J3 T represents the inertial time constant of mass B in the low-pressure cylinder. J4 K represents the inertial time constant of the generator mass. 12 K represents the stiffness coefficient of the shaft segment between the high-pressure cylinder mass block and the low-pressure cylinder mass block A. 23 K represents the stiffness coefficient of the shaft segment between low-pressure cylinder block A and low-pressure cylinder block B. 34 D1 represents the stiffness coefficient of the shaft segment between the low-pressure cylinder B mass and the synchronous motor mass; D2 represents the mechanical damping coefficient of the high-pressure cylinder mass; D3 represents the mechanical damping coefficient of the low-pressure cylinder A mass; D4 represents the mechanical damping coefficient of the synchronous motor mass; and a mass represents a component module with mass in the shaft system. b Indicates the rated frequency of the synchronous generator set. Indicates taking the matrix The third element, f, represents the harmonic frequency, ω B Indicates the rated angular frequency. Indicates taking the matrix The third element;

[0077] Step S5: Obtain the synchronous motor parameters. Based on the synchronous motor parameters and the above calculation formulas, generate the resonant impedance formula at frequency f in the power system harmonic power flow or harmonic resonance calculation software.

[0078]

[0079]

[0080]

[0081]

[0082]

[0083]

[0084]

[0085]

[0086]

[0087]

[0088] in, Represents the harmonic impedance model. This represents the initial harmonic impedance model, where f represents the harmonic frequency. b The rated frequency of the synchronous motor is represented by S. b U represents the rated apparent power of the synchronous motor. b f represents the rated line voltage of the synchronous motor. b The rated frequency of the synchronous motor is represented by r. a x represents the stator resistance of a synchronous motor. l The stator leakage reactance of a synchronous motor, x d x' represents the direct-axis synchronous reactance of a synchronous motor. d x″ represents the direct-axis transient reactance of a synchronous motor. d x represents the direct-axis subtransient reactance of a synchronous motor. q x' represents the quadrature-axis synchronous reactance of a synchronous motor. q x″ represents the quadrature-axis transient reactance of a synchronous motor. q T' represents the quadrature-axis subtransient reactance of a synchronous motor. d0 T″ represents the direct-axis transient open-circuit time constant of a synchronous motor. d0 T' represents the direct-axis subtransient open-circuit time constant of a synchronous motor. q0 T″ represents the quadrature-axis transient open-circuit time constant of a synchronous motor. q0 This represents the quadrature-axis subtransient open-circuit time constant of a synchronous motor.

[0089] Step S6: Based on the selected operating frequency f, determine how to simulate the harmonic impedance characteristics of the synchronous generator at frequency f in the power system harmonic flow or harmonic resonance calculation software. When the absolute value of the selected operating frequency f is less than 100Hz, the harmonic impedance characteristic Z(f) of the synchronous generator is simulated as a 2*2 matrix in the power system harmonic flow or harmonic resonance calculation software; when the absolute value of the selected operating frequency f is greater than 100Hz, the harmonic impedance characteristic Z(f) of the synchronous generator is simulated as a one-dimensional complex number in the power system harmonic flow or harmonic resonance calculation software. The mathematical representation is as follows:

[0090]

[0091] Where f represents the harmonic frequency, Let Z(f) represent the harmonic impedance model, where Z(f) represents the one-dimensional or two-dimensional harmonic impedance. Indicates taking the matrix The element in the first row and first column.

[0092] This application also provides a device for determining harmonic impedance. It should be noted that the device for determining harmonic impedance in this application can be used to execute the method for determining harmonic impedance provided in this application. This device is used to implement the above embodiments and preferred embodiments; details already described will not be repeated. As used below, the term "module" can refer to a combination of software and / or hardware that performs a predetermined function. Although the device described in the following embodiments is preferably implemented in software, hardware implementation, or a combination of software and hardware, is also possible and contemplated.

[0093] The following describes the harmonic impedance determination device provided in the embodiments of this application.

[0094] Figure 6 This is a schematic diagram of a harmonic impedance determination device according to an embodiment of this application. Figure 6 As shown, the device includes:

[0095] The acquisition unit 10 is used to acquire the initial operating parameters of the synchronous generator set, wherein the synchronous generator set includes at least a synchronous motor, an excitation system, a shaft system and a prime mover speed control system, and the initial operating parameters include at least the power angle of the synchronous motor.

[0096] Specifically, this application establishes a calculation model for harmonic impedance considering the influence of shaft system parameters of the synchronous generator set. It mainly considers the synchronous motor, excitation system, shaft system, and prime mover speed control system within the synchronous generator set. First, initial operating parameters are obtained, including the power angle δ0 of the synchronous generator set, the voltage amplitude V0 of the synchronous motor, and the direct-axis component u of the synchronous motor voltage. d0 The quadrature axis component u of the synchronous motor voltage q0 The direct-axis component i of the synchronous motor current d0 The quadrature axis component i of the synchronous motor current q0 The direct-axis component of the subtransient electromotive force E″ d0 The quadrature component of the subtransient electromotive force E″ q0 .

[0097] The first determining unit 20 is used to acquire the excitation system parameters in the synchronous generator set, generate an excitation voltage model based on the initial operating parameters and the excitation system parameters, and determine the excitation voltage through the excitation voltage model.

[0098] Specifically, after obtaining the initial operating parameters, the excitation system parameters are obtained, including: the time constant of the filter, the gain of the voltage regulator, the proportional-integral adjustment factor, the time constant of the voltage regulator, the gain of the voltage regulator, the time constant of the amplifier in the voltage regulator, the gain of the steady loop of the voltage regulator, the time constant of the steady loop of the voltage regulator, etc. Based on the initial operating parameters and the excitation system parameters, the excitation voltage model can be established and the excitation voltage can be determined.

[0099] The second determining unit 30 is used to obtain the shaft system parameters in the synchronous generator set, generate an electromagnetic torque model based on the shaft system parameters, and determine the electromagnetic torque through the electromagnetic torque model.

[0100] Specifically, the shaft system parameters are obtained, including: the inertia time constant of the high-pressure cylinder mass, the inertia time constant of the low-pressure cylinder A mass, the inertia time constant of the low-pressure cylinder B mass, the inertia time constant of the generator mass, the stiffness coefficient of the shaft segment between the high-pressure cylinder mass and the low-pressure cylinder A mass, and the rated frequency, etc. An electromagnetic torque model is established based on the shaft system parameters and the electromagnetic torque is calculated.

[0101] The third determining unit 40 is used to obtain the synchronous motor parameters in the synchronous generator set, generate a harmonic impedance model based on the excitation voltage, electromagnetic torque and synchronous motor parameters, and determine the harmonic impedance through the harmonic impedance model in order to perform harmonic power flow and harmonic stability analysis on the power system where the synchronous generator set is located.

[0102] Specifically, synchronous motor parameters are obtained, and a harmonic impedance model is generated based on the excitation voltage, electromagnetic torque, and synchronous motor parameters. The harmonic impedance is then determined, and the harmonic impedance characteristics of the synchronous unit are accurately simulated while considering the influence of shaft system, windings, etc. This allows for a more precise analysis of the harmonic power flow and harmonic stability characteristics of the power system, and better guidance for the safe and stable operation of the power system.

[0103] This embodiment obtains the initial operating parameters and excitation system parameters of the synchronous generator set, generates an excitation voltage model, generates an electromagnetic torque model based on the shaft system parameters, and generates a harmonic impedance model based on the excitation voltage, electromagnetic torque, and synchronous generator parameters. The harmonic impedance is then determined using this model. Compared to existing technologies that fail to consider the influence of the synchronous generator set's shaft system, windings, and control dynamics when determining harmonic impedance, leading to inaccurate harmonic impedance calculations, this application can obtain more accurate harmonic impedance based on the synchronous generator set's shaft system and winding parameters. This allows for precise analysis of the harmonic power flow and harmonic stability characteristics of the power system, better guiding the safe and stable operation of the power system. Therefore, it solves the problem of inaccurate harmonic impedance calculations in existing technologies, leading to inaccurate calculations of power system harmonic power flow and harmonic stability. This achieves accurate determination of harmonic impedance, thereby enabling precise analysis of the power system's harmonic power flow and harmonic stability characteristics, and better guiding the safe and stable operation of the power system.

[0104] As an optional solution, the first determining unit includes a first generation module, a second generation module, and a third generation module, wherein the first generation module is used to generate a first transfer function based on the excitation system parameters. The excitation system is controlled by negative feedback control, G v (f) represents the first transfer function, f represents the harmonic frequency, and T R K represents the time constant of the filter, and K represents the gain of the voltage regulator. V This represents the proportional-integral (PI) adjustment factor, where T1, T2, T3, and T4 are the time constants of the voltage regulator, and K is the input voltage regulator ... A T is the gain of the voltage regulator. A K represents the time constant of the amplifier in the voltage regulator. F T is the gain of the steady-state loop of the voltage regulator. F The steady-state loop time constant of the voltage regulator is defined; the filter and voltage regulator are included in the excitation system, and the amplifier is included in the voltage regulator; the second generation module is used to generate a second transfer function based on the first transfer function and the initial operating parameters. in, This represents the second transfer function, δ0 represents the initial power angle of the synchronous generator set, V0 is the initial voltage amplitude of the synchronous motor, and u d0 u represents the initial component of the direct-axis voltage of the synchronous motor. q0 The third generation module represents the initial component of the quadrature-axis voltage of the synchronous motor; it is used to generate the excitation voltage model based on the second transfer function. Among them, u d u represents the direct-axis voltage component of a synchronous motor. qThis represents the quadrature-axis voltage component of the synchronous motor. This device calculates the transfer function of the excitation system, thus generating a calculation model for the excitation voltage based on the transfer function.

[0105] Specifically, there are various models for the excitation system of synchronous generator units. The commonly used model is the FV-type excitation system model, where the ratio of generator terminal voltage to generator frequency (V / F) is within a certain operating range during normal generator operation. The excitation system uses negative feedback control; therefore, the excitation system can be represented using a negative feedback control block diagram from automatic control principles. Then, the transfer function of the excitation system is calculated based on the negative feedback control system. Therefore, the excitation system parameters are first obtained, including: the time constant of the filter, the gain of the voltage regulator, the proportional-integral adjustment factor, the time constant of the voltage regulator, the gain of the voltage regulator, the time constant of the amplifier in the voltage regulator, the gain of the voltage regulator's steady-state loop, and the time constant of the voltage regulator's steady-state loop. The harmonic frequencies also need to be obtained. A first transfer function is generated based on these parameters. The first transfer function is multiplied by the initial operating parameters to obtain a second transfer function. The second transfer function is then multiplied by the direct-axis and quadrature-axis components of the synchronous generator voltage to obtain the final excitation system voltage model, and the excitation voltage is calculated.

[0106] To accurately calculate the electromagnetic torque, the second determining unit includes a fourth generation module and a fifth generation module. The fourth generation module generates an initial electromagnetic torque model based on the shaft system parameters; the fifth generation module generates an electromagnetic torque model-T based on the initial electromagnetic torque model. e (f)=J eq (f)ω(f), where J eq (f) represents the initial electromagnetic torque model, ω(f) represents the speed of the synchronous motor, and f represents the harmonic frequency.

[0107] Specifically, the shaft system refers to the transmission system in a propulsion device, consisting mainly of drive shafts, from the main engine output shaft flange to the propeller. Therefore, the shaft system exhibits electromagnetic torque, which is a crucial parameter of synchronous generator sets. The process begins by obtaining the shaft system parameters, generating an electromagnetic torque calculation model based on these parameters, and then calculating the electromagnetic torque.

[0108] The fourth generation module mentioned above includes a first generation submodule, used to generate the initial electromagnetic torque model. in, , T J1 T represents the inertial time constant of the mass in a high-pressure cylinder. J2 T represents the inertial time constant of mass A in the low-pressure cylinder. J3 T represents the inertial time constant of mass B in the low-pressure cylinder. J4 K represents the inertial time constant of the generator mass.12 K represents the stiffness coefficient of the shaft segment between the high-pressure cylinder mass block and the low-pressure cylinder mass block A. 23 K represents the stiffness coefficient of the shaft segment between low-pressure cylinder block A and low-pressure cylinder block B. 34 D1 represents the stiffness coefficient of the shaft segment between the low-pressure cylinder B mass and the synchronous motor mass; D2 represents the mechanical damping coefficient of the high-pressure cylinder mass; D3 represents the mechanical damping coefficient of the low-pressure cylinder A mass; D4 represents the mechanical damping coefficient of the synchronous motor mass; and a mass represents a component module with mass in the shaft system. b Indicates the rated frequency of the synchronous generator set. Indicates taking the matrix The third element, ω B Indicates the rated angular frequency.

[0109] Specifically, the shaft system includes the high-pressure cylinder mass block, the low-pressure cylinder A mass block, the low-pressure cylinder B mass block, and the generator mass block. The shaft system parameters include: the inertia time constant of the high-pressure cylinder mass block, the inertia time constant of the low-pressure cylinder A mass block, the inertia time constant of the low-pressure cylinder B mass block, the inertia time constant of the generator mass block, the stiffness coefficient of the shaft segment between the high-pressure cylinder mass block and the low-pressure cylinder A mass block, the stiffness coefficient of the shaft segment between the low-pressure cylinder A mass block and the low-pressure cylinder B mass block, the stiffness coefficient of the shaft segment between the low-pressure cylinder B mass block and the synchronous motor mass block, the mechanical damping coefficient of the high-pressure cylinder mass block, the mechanical damping coefficient of the low-pressure cylinder A mass block, the mechanical damping coefficient of the low-pressure cylinder B mass block, and the mechanical damping coefficient of the synchronous motor mass block. It is also necessary to obtain the rated frequency and rated angular frequency of the synchronous generator set, and then generate an initial electromagnetic torque model based on the above parameters.

[0110] In some embodiments, the third determining unit includes a sixth generation module and a seventh generation module, wherein the sixth generation module is used to generate an initial harmonic impedance model based on the excitation voltage, electromagnetic torque, and synchronous motor parameters; and the seventh generation module is used to generate a harmonic impedance model based on the initial harmonic impedance model. in, This represents the initial harmonic impedance model. The device generates an initial harmonic impedance calculation model based on the excitation voltage and electromagnetic torque, which allows for accurate calculation of harmonic impedance.

[0111] Specifically, after calculating the excitation voltage and electromagnetic torque as described above, an initial harmonic impedance calculation model is generated based on the relationship between the excitation voltage and electromagnetic torque and the harmonic impedance, so as to ensure that the harmonic impedance is accurately calculated in the subsequent process.

[0112] To further accurately calculate the harmonic impedance, in some embodiments, the sixth generation module includes a second generation submodule for generating an initial harmonic impedance model based on the excitation voltage, electromagnetic torque, and synchronous motor parameters.

[0113] in,

[0114] S b U represents the rated apparent power of the synchronous motor. b f represents the rated line voltage of the synchronous motor. b The rated frequency of the synchronous motor is represented by r. a x represents the stator resistance of a synchronous motor. l The stator leakage reactance of a synchronous motor, x d x' represents the direct-axis synchronous reactance of a synchronous motor. d x″ represents the direct-axis transient reactance of a synchronous motor. d x represents the direct-axis subtransient reactance of a synchronous motor. q x' represents the quadrature-axis synchronous reactance of a synchronous motor. q x″ represents the quadrature-axis transient reactance of a synchronous motor. q T′ represents the quadrature-axis subtransient reactance of a synchronous motor. d0 T″ represents the direct-axis transient open-circuit time constant of a synchronous motor. d0 T' represents the direct-axis subtransient open-circuit time constant of a synchronous motor. q0 T″ represents the quadrature-axis transient open-circuit time constant of a synchronous motor. q0 This represents the quadrature-axis subtransient open-circuit time constant of a synchronous motor.

[0115] Specifically, the synchronous motor parameters include: the rated apparent power of the synchronous motor, the rated line voltage of the synchronous motor, the rated frequency of the synchronous motor, the stator resistance of the synchronous motor, the stator leakage reactance of the synchronous motor, the direct-axis synchronous reactance of the synchronous motor, the direct-axis transient reactance of the synchronous motor, the direct-axis subtransient reactance of the synchronous motor, the quadrature-axis synchronous reactance of the synchronous motor, the quadrature-axis transient reactance of the synchronous motor, the quadrature-axis subtransient reactance of the synchronous motor, the direct-axis transient open-circuit time constant of the synchronous motor, the direct-axis subtransient open-circuit time constant of the synchronous motor, the quadrature-axis transient open-circuit time constant of the synchronous motor, and the quadrature-axis subtransient open-circuit time constant of the synchronous motor. Based on the above synchronous motor parameters, excitation voltage, and electromagnetic torque, a harmonic impedance calculation model is generated, and the harmonic impedance is calculated.

[0116] To determine the harmonic impedance at different operating frequencies, in some embodiments, the third determining unit includes a first determining submodule and a second determining submodule. The first determining submodule is used when the absolute value of the harmonic frequency is less than a preset frequency, and the harmonic impedance is a two-dimensional matrix. Where f represents the harmonic frequency; the second determining submodule is used to determine the harmonic impedance as a one-dimensional complex number when the absolute value of the harmonic frequency is greater than the preset frequency.

[0117] Specifically, the harmonic impedance characteristics of the synchronous generator set at harmonic frequency f are simulated in the power system harmonic power flow or harmonic resonance calculation software based on the magnitude of the harmonic frequency f. A preset frequency of 100Hz is selected. When the absolute value of the selected harmonic frequency f is less than 100Hz, the harmonic impedance characteristic Z(f) of the synchronous generator set is simulated as a 2*2 matrix in the power system harmonic power flow or harmonic resonance calculation software. When the absolute value of the selected harmonic frequency f is greater than 100Hz, the harmonic impedance characteristic Z(f) of the synchronous generator set is simulated as a one-dimensional complex number in the power system harmonic power flow or harmonic resonance calculation software.

[0118] The device for determining harmonic impedance includes a processor and a memory. The aforementioned acquisition unit, first determination unit, second determination unit, and third determination unit are all stored as program units in the memory. The processor executes the aforementioned program units stored in the memory to achieve the corresponding functions. All of the above modules are located in the same processor; alternatively, the above modules may be located in different processors in any combination.

[0119] The processor contains a kernel, which retrieves the corresponding program units from memory. One or more kernels can be configured, and adjusting kernel parameters can address the problem of inaccurate harmonic impedance calculations in existing technologies.

[0120] The memory may include non-permanent memory in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM, and the memory includes at least one memory chip.

[0121] It is obvious to those skilled in the art that the modules or steps of the present invention described above can be implemented using general-purpose computing devices. They can be centralized on a single computing device or distributed across a network of multiple computing devices. They can be implemented using computer-executable program code, and thus can be stored in a storage device for execution by a computing device. In some cases, the steps shown or described can be performed in a different order than those described herein, or they can be fabricated as separate integrated circuit modules, or multiple modules or steps can be fabricated as a single integrated circuit module. Thus, the present invention is not limited to any particular combination of hardware and software.

[0122] 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.

[0123] 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.

[0124] 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.

[0125] 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.

[0126] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0127] Memory may include non-persistent memory in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM. Memory is an example of computer-readable media.

[0128] Computer-readable media includes both permanent and non-permanent, removable and non-removable media that can store information using any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic magnetic disk storage or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable media does not include transient computer-readable media, such as modulated data signals and carrier waves.

[0129] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0130] As can be seen from the above description, the embodiments of this application achieve the following technical effects:

[0131] 1) In the method for determining harmonic impedance of this application, the initial operating parameters and excitation system parameters of the synchronous generator set are obtained, an excitation voltage model is generated, an electromagnetic torque model is generated based on the shaft system parameters, and a harmonic impedance model is generated based on the excitation voltage, electromagnetic torque, and synchronous generator parameters. The harmonic impedance is then determined through the harmonic impedance model. Compared with the prior art, which fails to consider the influence of the synchronous generator set's shaft system, windings, and control dynamics when determining harmonic impedance, leading to inaccurate harmonic impedance calculations, this application can obtain more accurate harmonic impedance based on the synchronous generator set's shaft system and winding parameters. This allows for precise analysis of power system harmonic flow and harmonic stability. Therefore, it solves the problem of inaccurate power system harmonic flow and harmonic stability calculations caused by inaccurate harmonic impedance calculations in the prior art, achieving the effect of accurately determining harmonic impedance and thus more accurately analyzing the harmonic flow and harmonic stability characteristics of the power system.

[0132] 2) The harmonic impedance determination device of this application acquires the initial operating parameters and excitation system parameters of the synchronous generator set, generates an excitation voltage model, generates an electromagnetic torque model based on the shaft system parameters, and generates a harmonic impedance model based on the excitation voltage, electromagnetic torque, and synchronous generator parameters. The harmonic impedance is then determined using this model. Compared to existing technologies that fail to consider the influence of the synchronous generator set's shaft system, windings, and control dynamics when determining harmonic impedance, leading to inaccurate harmonic impedance calculations, this application can obtain more accurate harmonic impedance based on the synchronous generator set's shaft system and winding parameters. This allows for precise analysis of power system harmonic flow and harmonic stability. Therefore, it solves the problem of inaccurate power system harmonic flow and harmonic stability calculations caused by inaccurate harmonic impedance calculations in existing technologies, achieving accurate determination of harmonic impedance and thus enabling more precise analysis of power system harmonic flow and harmonic stability characteristics.

[0133] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for determining harmonic impedance, characterized in that, include: The initial operating parameters of the synchronous generator set are obtained, wherein the synchronous generator set includes at least a synchronous motor, an excitation system, a shaft system and a prime mover speed control system, and the initial operating parameters include at least the power angle of the synchronous motor; Obtain the excitation system parameters in the synchronous generator set, generate an excitation voltage model based on the initial operating parameters and the excitation system parameters, and determine the excitation voltage through the excitation voltage model; Obtain the shaft system parameters in the synchronous generator set, generate an electromagnetic torque model based on the shaft system parameters, and determine the electromagnetic torque through the electromagnetic torque model; The synchronous motor parameters in the synchronous generator set are obtained. A harmonic impedance model is generated based on the excitation voltage, the electromagnetic torque, and the synchronous motor parameters. The harmonic impedance is determined using the harmonic impedance model to perform harmonic power flow and harmonic stability analysis on the power system in which the synchronous generator set is located. Generating a harmonic impedance model based on the excitation voltage, the electromagnetic torque, and the synchronous motor parameters includes: generating an initial harmonic impedance model based on the excitation voltage, the electromagnetic torque, and the synchronous motor parameters; and generating the harmonic impedance model based on the initial harmonic impedance model. ,in, , This represents the harmonic impedance model. This represents the initial harmonic impedance model. f Indicates harmonic frequency, f b This indicates the rated frequency of the synchronous motor. Generating an initial harmonic impedance model based on the excitation voltage, the electromagnetic torque, and the synchronous motor parameters includes: generating an initial harmonic impedance model based on the excitation voltage, the electromagnetic torque, and the synchronous motor parameters. , in, , , ， ， ， ， ， ， ， S b This indicates the rated apparent power of the synchronous motor. U b This indicates the rated line voltage of the synchronous motor. r a This represents the stator resistance of the synchronous motor. x l This indicates the stator leakage reactance of the synchronous motor. x d This indicates the direct-axis synchronous reactance of the synchronous motor. This represents the direct-axis transient reactance of the synchronous motor. This represents the direct-axis subtransient reactance of the synchronous motor. x q This represents the quadrature-axis synchronous reactance of the synchronous motor. This represents the quadrature-axis transient reactance of the synchronous motor. This represents the quadrature-axis subtransient reactance of the synchronous motor. This represents the direct-axis transient open-circuit time constant of the synchronous motor. This represents the direct-axis subtransient open-circuit time constant of the synchronous motor. This represents the quadrature-axis transient open-circuit time constant of the synchronous motor. This represents the quadrature-axis subtransient open-circuit time constant of the synchronous motor.

2. The determination method according to claim 1, characterized in that, Generate an excitation voltage model based on the initial operating parameters and the excitation system parameters, including: A first transfer function is generated based on the excitation system parameters. ， The excitation system is controlled by negative feedback control, G v (f) represents the first transfer function. f Indicates harmonic frequency, T R This represents the time constant of the filter. K Indicates the gain of the voltage regulator. K V This represents the proportional-integral adjustment factor. T 1. T 2. T 3 and T 4 represents the time constant of the voltage regulator. K A The gain of the voltage regulator. T A This represents the time constant of the amplifier in the voltage regulator. K F The gain of the stable circuit of the voltage regulator. T F The steady-state loop time constant of the voltage regulator is defined here; the filter and the voltage regulator are included in the excitation system; and the amplifier is included in the voltage regulator. Generate a second transfer function based on the first transfer function and the initial operating parameters. ,in, This represents the second transfer function. δ 0 represents the initial power angle of the synchronous generator set. V 0 represents the initial voltage amplitude of the synchronous motor. u d0 This represents the initial component of the direct-axis voltage of the synchronous motor. u q0 This represents the initial component of the quadrature-axis voltage of the synchronous motor; The excitation voltage model is generated based on the second transfer function. ,in, E f (f) The excitation voltage, u d u represents the direct-axis voltage component of the synchronous motor. q This represents the quadrature-axis voltage component of the synchronous motor.

3. The determination method according to claim 1, characterized in that, Generate an electromagnetic torque model based on the shaft system parameters, including: An initial electromagnetic torque model is generated based on the shaft system parameters; The electromagnetic torque model is generated based on the initial electromagnetic torque model. , among which, T e (f) represents the electromagnetic torque, J eq (f) represents the initial electromagnetic torque model, and w(f) represents the rotational speed of the synchronous motor. f Indicates the harmonic frequency.

4. The determination method according to claim 3, characterized in that, Generate an initial electromagnetic torque model based on the shaft system parameters, including: Generate the initial electromagnetic torque model ,in, , T J1 This represents the inertial time constant of the high-pressure cylinder mass. T J2 This represents the inertial time constant of mass A in the low-pressure cylinder. T J3 This represents the inertial time constant of mass B in the low-pressure cylinder. T J4 The inertial time constant of the generator mass is represented. K 12 This represents the stiffness coefficient of the shaft segment between the high-pressure cylinder block and the low-pressure cylinder A block. K 23 This represents the stiffness coefficient of the shaft segment between the low-pressure cylinder A block and the low-pressure cylinder B block. K 34 This represents the stiffness coefficient of the shaft segment between the low-pressure cylinder B mass and the synchronous motor mass. D 1 represents the mechanical damping coefficient of the high-pressure cylinder mass. D 2 represents the mechanical damping coefficient of the low-pressure cylinder A mass block. D 3 represents the mechanical damping coefficient of the low-pressure cylinder B mass. D 4 represents the mechanical damping coefficient of the mass, where the mass represents a component module with mass in the shaft system, f b This indicates the rated frequency of the synchronous generator set. Indicates taking the matrix The third element, w B Indicates the rated angular frequency.

5. The determination method according to claim 1, characterized in that, Determining harmonic impedance using the aforementioned harmonic impedance model includes: When the absolute value of the harmonic frequency is less than a preset frequency, the harmonic impedance is a two-dimensional matrix. , where Z( f) The harmonic impedance is represented in one or two dimensions; When the absolute value of the harmonic frequency is greater than a preset frequency, the harmonic impedance is a one-dimensional complex number. ,in, This represents the elements in the first row and first column of the harmonic impedance model.

6. A device for determining harmonic impedance, characterized in that, include: An acquisition unit is used to acquire the initial operating parameters of a synchronous generator set, wherein the synchronous generator set includes at least a synchronous motor, an excitation system, a shaft system, and a prime mover speed control system, and the initial operating parameters include at least the power angle of the synchronous motor; The first determining unit is used to acquire the excitation system parameters in the synchronous generator set, generate an excitation voltage model based on the initial operating parameters and the excitation system parameters, and determine the excitation voltage through the excitation voltage model. The second determining unit is used to obtain the shaft system parameters in the synchronous generator set, generate an electromagnetic torque model based on the shaft system parameters, and determine the electromagnetic torque through the electromagnetic torque model. The third determining unit is used to acquire the synchronous motor parameters in the synchronous generator set, generate a harmonic impedance model based on the excitation voltage, the electromagnetic torque, and the synchronous motor parameters, and determine the harmonic impedance through the harmonic impedance model in order to perform harmonic power flow and harmonic stability analysis on the power system in which the synchronous generator set is located. The third determining unit includes a sixth generation module and a seventh generation module, wherein the sixth generation module is used to generate an initial harmonic impedance model based on the excitation voltage, the electromagnetic torque, and the synchronous motor parameters; and the seventh generation module is used to generate the harmonic impedance model based on the initial harmonic impedance model. ,in, , This represents the harmonic impedance model. This represents the initial harmonic impedance model. f Indicates harmonic frequency, f b This indicates the rated frequency of the synchronous motor. The sixth generation module includes a second generation submodule, used to generate an initial harmonic impedance model based on the excitation voltage, the electromagnetic torque, and the synchronous motor parameters. in, , , , , , , , , , S b This indicates the rated apparent power of the synchronous motor. U b This indicates the rated line voltage of the synchronous motor. r a This represents the stator resistance of the synchronous motor. x l This indicates the stator leakage reactance of the synchronous motor. x d This indicates the direct-axis synchronous reactance of the synchronous motor. This represents the direct-axis transient reactance of the synchronous motor. This represents the direct-axis subtransient reactance of the synchronous motor. x q This represents the quadrature-axis synchronous reactance of the synchronous motor. This represents the quadrature-axis transient reactance of the synchronous motor. This represents the quadrature-axis subtransient reactance of the synchronous motor. This represents the direct-axis transient open-circuit time constant of the synchronous motor. This represents the direct-axis subtransient open-circuit time constant of the synchronous motor. This represents the quadrature-axis transient open-circuit time constant of the synchronous motor. This represents the quadrature-axis subtransient open-circuit time constant of the synchronous motor.

7. A computer-readable storage medium, characterized in that, The computer-readable storage medium includes a stored program, wherein, when the program is executed, it controls the device on which the computer-readable storage medium is located to perform the determination method according to any one of claims 1 to 5.

8. An electronic device, characterized in that, include: One or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the one or more programs including methods for performing the determination method according to any one of claims 1 to 5.

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