Method, system and device for calculating minimum reactive power compensation capacity of asynchronous machine load and medium

Abstract

This invention belongs to the field of asynchronous motor load voltage control technology. It discloses a method, system, equipment, and medium for calculating the minimum reactive power compensation capacity of asynchronous motor loads. This addresses the problem that existing technologies cannot accurately quantify the minimum reactive power demand of asynchronous motors under transient voltage stability critical states, leading to insufficient compensation causing instability or excessive compensation resulting in waste. The method includes: deriving analytical expressions for electromagnetic torque, active power, and reactive power based on the steady-state equivalent circuit of the asynchronous motor; obtaining a given electromagnetic torque and substituting it into the analytical expression for electromagnetic torque to solve for the slip rate; substituting the slip rate into the analytical expressions for active and reactive power, gradually reducing the voltage step-by-step from a preset voltage, calculating the active and reactive power corresponding to each voltage point-by-point, plotting voltage-active power characteristic curves and voltage-reactive power characteristic curves, and determining the critical minimum voltage and the reactive power value corresponding to that voltage as the minimum reactive power compensation capacity.

Description

Technical Field

[0001] This invention belongs to the field of asynchronous machine load voltage control technology, specifically relating to the calculation method, system, equipment, and medium for the minimum reactive power compensation capacity of asynchronous machine loads. Background Technology

[0002] Asynchronous motors are the most widely used power loads in industrial production and power distribution networks, and their operating characteristics have a significant impact on the voltage stability of the regional power grid. When voltage dips occur in the power grid, asynchronous motors are prone to speed loss and a sharp increase in reactive power consumption, which can lead to voltage instability or even load disconnection.

[0003] Currently, in engineering practice, reactive power compensation capacity configuration for asynchronous motor loads often relies on empirical estimation methods or simplified engineering calculation formulas. Empirical estimation methods typically determine the compensation capacity roughly based on a certain proportion of the motor capacity, without considering the actual operating conditions of the motor, load characteristics, and the range of grid voltage fluctuations, resulting in low compensation accuracy. Simplified estimation methods often ignore the influence of parameters such as stator resistance and excitation reactance on reactive power, using approximate equivalent circuits for derivation, which makes it difficult to accurately reflect the nonlinear reactive power response characteristics of asynchronous motors during voltage dips.

[0004] In summary, existing technologies cannot accurately quantify the minimum reactive power requirement of asynchronous machines under transient voltage stability critical conditions. This leads to either insufficient compensation in practical engineering, resulting in the asynchronous machine still having the risk of instability after voltage disturbances, or excessive compensation, causing waste of reactive power compensation device capacity and reduced economic efficiency. Summary of the Invention

[0005] Based on the aforementioned shortcomings and deficiencies in the prior art, one of the objectives of this invention is to at least solve one or more of the aforementioned problems in the prior art. In other words, one of the objectives of this invention is to provide a method, system, device, and medium for calculating the minimum reactive power compensation capacity of asynchronous machine loads that meets one or more of the aforementioned requirements, so as to accurately quantify the minimum reactive power compensation capacity of the asynchronous machine under the critical state of transient voltage stability, and avoid instability caused by insufficient compensation or waste caused by excessive compensation.

[0006] To achieve the above-mentioned objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a method for calculating the minimum reactive power compensation capacity of an asynchronous machine load, comprising the following steps: S1. Derive analytical expressions for electromagnetic torque, active power, and reactive power based on the steady-state equivalent circuit model of an asynchronous motor. S2. Obtain the given electromagnetic torque and substitute it into the analytical expression of electromagnetic torque derived in step S1 to solve for the corresponding slip rate. S3. Substitute the slip obtained in step S2 into the analytical expressions of active power and reactive power derived in step S1. Starting from the preset voltage, gradually reduce the voltage with a preset step size, calculate the active power and reactive power corresponding to each voltage value point by point, and draw the voltage-active power characteristic curve and voltage-reactive power characteristic curve based on the calculation results. S4. Determine the critical minimum voltage for transient voltage stability of the asynchronous motor based on the voltage-active power characteristic curve plotted in step S3. S5. From the voltage-reactive power characteristic curve drawn in step S3, extract the reactive power value corresponding to the critical minimum voltage determined in step S4, and use the reactive power value as the minimum reactive power compensation capacity required to maintain the stable operation of the asynchronous machine.

[0007] As a preferred option: The rotor-side parameters of the steady-state equivalent circuit model have been converted to the stator-side parameters; The parameters of the steady-state equivalent circuit model include stator resistance, stator reactance, rotor equivalent resistance, rotor equivalent reactance, magnetizing reactance, and slip.

[0008] As a preferred approach, the analytical expression for the electromagnetic torque derived in step S1 is: , In the formula, Electromagnetic power, Stator-side phase voltage, The rotor equivalent resistance, For stator resistance, For stator reactance, For rotor equivalent reactance, For slippage, To synchronize mechanical angular velocity.

[0009] As a preferred option: In step S1, when deriving the analytical expressions for active power and reactive power, the steady-state equivalent circuit is subjected to Thevenin equivalence to obtain the Thevenin equivalent circuit model. Based on the Thevenin equivalent circuit model, analytical expressions for the active power and reactive power are derived.

[0010] As a preferred embodiment, the analytical expressions for the active power and reactive power are as follows: , , In the formula, Stator-side phase voltage, The active equivalent resistance is the resistance of the rotor circuit and the excitation branch connected in parallel. For stator resistance, This is the reactive equivalent reactance after the excitation reactance and rotor leakage reactance are connected in parallel. This refers to the stator reactance.

[0011] As a preferred option, in step S3: The preset voltage is 1.05 times the per-unit value of the rated voltage; The preset step size is 0.01 times the per-unit value of the rated voltage.

[0012] As a preferred embodiment, the critical minimum voltage in step S4 is determined as follows: In the voltage-active power characteristic curve, the voltage value corresponding to the lowest point of the curve is taken as the critical minimum voltage for transient voltage stability of the asynchronous machine.

[0013] Secondly, the present invention provides a minimum reactive power compensation capacity calculation system for asynchronous machine loads, used to implement the minimum reactive power compensation capacity calculation method as described in the first aspect.

[0014] Thirdly, the present invention provides an electronic device, the computer device including a memory, a processor and a computer program, wherein when the computer program is executed by the processor, it implements the minimum reactive power compensation capacity calculation method as described in the first aspect.

[0015] Fourthly, the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the minimum reactive power compensation capacity calculation method as described in the first aspect.

[0016] Compared with the prior art, the present invention has the following beneficial effects: This invention, based on the steady-state equivalent circuit of an asynchronous motor, derives analytical expressions for electromagnetic torque, active power, and reactive power. By plotting voltage-active power characteristic curves and voltage-reactive power characteristic curves, it determines the critical minimum voltage for transient voltage stability of the asynchronous motor and extracts the corresponding reactive power value as the minimum reactive power compensation capacity. This method changes the traditional approach of relying on empirical estimation or simplified formula calculations, achieving precise quantification of the minimum reactive power compensation capacity and avoiding the risk of voltage instability due to insufficient compensation and the waste of resources caused by excessive compensation.

[0017] This invention directly determines the critical minimum voltage by identifying the lowest point in the voltage-active power characteristic curve. This voltage has a clear physical meaning—the minimum voltage threshold required for the asynchronous motor to maintain stable operation. Based on this, the corresponding reactive power value is extracted from the voltage-reactive power characteristic curve; this value represents the minimum reactive power compensation capacity required under critical steady-state conditions. The entire calculation process is conceptually clear, facilitating understanding and application by engineers, and can be widely applied to reactive power compensation configuration in distribution networks or industrial power systems containing asynchronous motor loads.

[0018] This invention uses a given electromagnetic torque as input and adapts to different load conditions by solving for the slip rate. Regardless of whether the asynchronous machine is under light load, rated load, or heavy load, the minimum reactive power compensation capacity under the corresponding operating condition can be calculated by adjusting the given electromagnetic torque parameters, demonstrating good adaptability and universality.

[0019] This invention provides a quantitative method that combines analytical derivation with graphical analysis. It can not only calculate the minimum reactive power compensation capacity, but also intuitively analyze the voltage stability boundary of asynchronous machines through voltage-active power characteristic curves and voltage-reactive power characteristic curves. This provides accurate and practical technical support for voltage stability assessment, reactive power compensation device selection and capacity configuration of systems with asynchronous machine loads.

[0020] Further or more detailed beneficial effects will be described in conjunction with specific embodiments in the detailed implementation. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a flowchart illustrating the minimum reactive power compensation capacity calculation method described in Embodiment 1 of the present invention.

[0023] Figure 2 This is a schematic diagram of the steady-state equivalent circuit model of the asynchronous motor described in Embodiment 1 of the present invention.

[0024] Figure 3 This is a schematic diagram of the Thevenin equivalent circuit model described in Embodiment 1 of the present invention.

[0025] Figure 4 This is a schematic diagram of the voltage-active power characteristic curve described in Embodiment 1 of the present invention.

[0026] Figure 5This is a schematic diagram of the voltage-reactive power characteristic curve described in Embodiment 1 of the present invention.

[0027] Figure 6 This is a schematic diagram of the voltage-active power characteristic curve when the electromagnetic torque is 0.8 as described in Embodiment 1 of the present invention.

[0028] Figure 7 This is a schematic diagram of the voltage-reactive power characteristic curve when the electromagnetic torque is 0.8 as described in Embodiment 1 of the present invention.

[0029] Figure 8 This is a structural diagram of the electronic device described in Embodiment 3 of the present invention.

[0030] Icon labels: 800. Electronic equipment; 801. Processor; 802. Communication bus; 803. User interface; 804. Network interface; 805. Memory. Detailed Implementation

[0031] 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.

[0032] In the following description, several embodiments of the present invention are provided. Different embodiments can be substituted or combined. Therefore, the present invention can also be considered to include all possible combinations of the same and / or different embodiments described. Thus, if one embodiment includes features A, B, and C, and another embodiment includes features B and D, then the present invention should also be considered to include embodiments containing one or more other possible combinations of A, B, C, and D, even if such embodiments are not explicitly described in the following text.

[0033] The following description provides examples and does not limit the scope, applicability, or examples set forth in the claims. Changes may be made to the function and arrangement of the described elements without departing from the scope of the invention. Various processes or components may be appropriately omitted, substituted, or added to the various examples. For example, the described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. Furthermore, features described with respect to some examples may be combined into other examples.

[0034] To facilitate a better understanding of the embodiments of the present invention, its application scenarios will be explained before providing a detailed explanation of the specific implementation methods.

[0035] The minimum reactive power compensation capacity calculation method described in the embodiments of this specification is applied to distribution networks or industrial power systems containing asynchronous machine loads. In these scenarios, the application of the minimum reactive power compensation capacity calculation method aims to accurately quantify the minimum reactive power compensation required to maintain the transient voltage stability of the asynchronous machine when the grid experiences voltage drop disturbances. This provides a basis for the capacity configuration of reactive power compensation devices and avoids voltage instability due to insufficient compensation or resource waste due to excessive compensation.

[0036] The following is a brief explanation of the asynchronous machine, minimum reactive power compensation capacity, steady-state equivalent circuit model, and electromagnetic torque involved in several embodiments of this specification: Asynchronous motors, also known as induction motors, are the most widely used power loads in industrial production and power distribution networks. When operating, asynchronous motors need to absorb active power from the power grid to drive the mechanical load, and simultaneously absorb reactive power to establish a rotating magnetic field. When the grid voltage drops, the reactive power consumption of the asynchronous motor increases sharply, which is one of the main factors causing voltage instability. In this manual, "asynchronous motor" and "asynchronous machine" have the same meaning.

[0037] The minimum reactive power compensation capacity refers to the minimum reactive power value required to maintain the stable operation of an asynchronous motor under the critical state of transient voltage stability. This value is the critical reactive power requirement calculated using the method described in this invention under a given electromagnetic torque condition. In practical engineering, configuring a reactive power compensation device with a capacity not less than this value can ensure that the asynchronous motor can still operate stably when the voltage drops to the critical value; if the compensation capacity is lower than this value, the asynchronous motor is at risk of voltage instability; if it is significantly higher than this value, it results in wasted device capacity.

[0038] The steady-state equivalent circuit model is an equivalent circuit that describes the electrical characteristics of an asynchronous motor during steady-state operation. This model is the basis for deriving the analytical expressions for electromagnetic torque, active power, and reactive power in this invention.

[0039] Electromagnetic torque refers to the driving torque transmitted from the stator side of an asynchronous motor to the rotor through electromagnetic induction, and is measured in per-unit values ​​or physical units. The magnitude of electromagnetic torque depends on the stator-side phase voltage, slip, and the motor's own parameters. In this invention, electromagnetic torque is used as a given input condition to inversely deduce the slip of the asynchronous motor under specific load conditions, and then calculate the corresponding active and reactive power.

[0040] Example 1: This embodiment provides a method for calculating the minimum reactive power compensation capacity of an asynchronous motor load. Taking an asynchronous motor on a certain load line as an example, it specifically explains how to calculate the minimum reactive power compensation capacity required to maintain the stable operation of the asynchronous motor using the method of this invention.

[0041] like Figure 1As shown, the method for calculating the minimum reactive power compensation capacity includes the following steps: Step S1: Derive analytical expressions for electromagnetic torque, active power, and reactive power based on the steady-state equivalent circuit model of the asynchronous motor.

[0042] First, construct the steady-state equivalent circuit model of the asynchronous motor, such as... Figure 2 As shown, the equivalent circuit includes stator-side parameters and rotor-side equivalent parameters, wherein... For stator resistance, Here, is the stator reactance, and is the rotor equivalent resistance. For rotor equivalent reactance, For the magnetizing reactance, This refers to the slip ratio. It should be noted that the rotor-side parameters have been converted to the stator-side parameters.

[0043] Based on the equivalent circuit described above, the analytical expression for the electromagnetic torque is derived. First, the electromagnetic power is calculated. Its expression is: (1), In equation (1), This refers to the rotor-side current after being referred to the stator side; eliminate Then, the stator-side phase voltage is obtained. Electromagnetic power Calculation formula: (2), Finally, electromagnetic torque is utilized. With electromagnetic power Synchronous mechanical angular velocity The correlation between the two is used to derive the electromagnetic torque. The parsing expression is: (3).

[0044] To facilitate the derivation of analytical expressions for active and reactive power, the following will be used: Figure 2 The steady-state equivalent circuit shown is subjected to Thevenin equivalence, resulting in the following: Figure 3 The Thevenin equivalent circuit model is shown.

[0045] According to Ohm's law for single-phase AC circuits, the effective value I of the stator-side input current is the ratio of the effective value of the voltage to the magnitude of the total impedance: (4), in, This is the total impedance of the equivalent circuit.

[0046] The active power absorbed by the stator side of the asynchronous motor is entirely consumed by the active resistive component of the circuit (including the stator resistance). Equivalent resistance of rotor This conforms to the basic formula for active power in AC circuits: (5), (6), Substituting the stator current I in equation (4) into the active power formula, we obtain the analytical expression for active power: (7), The reactive power absorbed by the stator side of the asynchronous motor is entirely consumed by the inductive components of the circuit (including stator leakage reactance). Equivalent leakage reactance of rotor This conforms to the basic formula for reactive power in AC circuits: (8), Substituting the stator current I in equation (4) into the reactive power formula, we obtain the analytical expression for reactive power: (9).

[0047] Step S2: Obtain the given electromagnetic torque and substitute it into the analytical expression for electromagnetic torque derived in step S1 to solve for the corresponding slip rate.

[0048] Specifically, the given electromagnetic torque Substituting into the electromagnetic torque expression of equation (3), we obtain the relationship with slip rate. The nonlinear equation is obtained by solving it numerically (e.g., the Newton-Raphson method), yielding a result consistent with the given equation. Corresponding unique slip This ensures the accuracy and convergence of the solution results.

[0049] Step S3: Substitute the slip obtained in step S2 into the analytical expressions for active power and reactive power derived in step S1. Starting from the preset voltage, gradually decrease the voltage at the preset step size, calculate the active power and reactive power corresponding to each voltage value point by point, and draw the voltage-active power characteristic curve and the voltage-reactive power characteristic curve based on the calculation results.

[0050] In this embodiment, the preset voltage is 1.05 times the per-unit value of the rated voltage, and the preset step size is 0.01 per-unit value. Starting with 1.05 times the per-unit value of the rated voltage, the voltage is gradually reduced in steps of 0.01 per-unit value until the voltage drops to the critical range where the asynchronous motor may become unstable.

[0051] Substitute the slip obtained from step S2 into the analytical expressions for active and reactive power shown in equations (7) and (9), calculate the active and reactive power corresponding to each voltage value point by point, and record all voltage-power data pairs.

[0052] With voltage (Per unit value) is the horizontal axis, with active power as the main component. reactive power Using the recorded voltage-power data pairs as the ordinate, plot the voltage-active power characteristic curve. Characteristic curves) and voltage-reactive power characteristic curves ( Characteristic curves), respectively as follows Figure 4 and Figure 5 As shown.

[0053] Step S4: Determine the critical minimum voltage for transient voltage stability of the asynchronous machine based on the voltage-active power characteristic curve plotted in step S3.

[0054] analyze Figure 4 The voltage-active power characteristic curve shown uses the voltage value corresponding to the lowest point A as the critical minimum voltage for transient voltage stability of the asynchronous motor. In this curve, the region to the left of point A is the stable operating region, and the region to the right of point A is the unstable operating region. When the system operating point crosses the stall point A, the voltage will enter an unstable state, and the system will be at risk of instability. This voltage is the minimum voltage threshold for the asynchronous motor to maintain stable operation; when the actual voltage is lower than this value, the asynchronous motor will experience speed stall and voltage instability.

[0055] Step S5: Extract the reactive power value corresponding to the critical minimum voltage determined in step S4 from the voltage-reactive power characteristic curve drawn in step S3, and use the reactive power value as the minimum reactive power compensation capacity required to maintain the stable operation of the asynchronous machine.

[0056] exist Figure 5 From the voltage-reactive power characteristic curves shown, find the reactive power value corresponding to the critical minimum voltage, and take this value as the minimum reactive power compensation capacity required to maintain the stable operation of the asynchronous machine. Figure 5 As can be seen, the slope of the curve is positive when the voltage V increases, indicating that the increased magnetization impedance loss is greater than the decreased leakage reactance loss; especially when approaching the stall point, reactive power consumption will increase significantly. This value is the minimum reactive power compensation capacity required to maintain the asynchronous motor in the critical state of transient voltage stability. By configuring a reactive power compensation device with this capacity, it can be ensured that the asynchronous motor can still operate stably when the voltage drops to the critical value, avoiding voltage instability and load disconnection.

[0057] This embodiment takes an asynchronous motor on a load line as the object, and provides a given electromagnetic torque. The value is 0.8. Following steps S1 to S5 above, the voltage-active power characteristic curve is plotted as follows: Figure 6 As shown, the voltage-reactive power characteristic curve is as follows: Figure 7 As shown.

[0058] exist Figure 6 In the voltage-active power characteristic curve shown, the voltage value corresponding to the lowest point A of the curve is the critical minimum voltage for transient voltage stability of the asynchronous motor. Figure 7 In the voltage-reactive power characteristic curve shown, the reactive power value corresponding to the critical minimum voltage is the minimum reactive power compensation capacity required to maintain the stable operation of the asynchronous machine.

[0059] In summary, this embodiment, based on the derivation of the equivalent circuit of the asynchronous machine and the analysis of the voltage-active power characteristic curve and the voltage-reactive power characteristic curve, accurately quantifies the minimum reactive power compensation capacity required for the critical stability of the asynchronous machine load, thus verifying the effectiveness and practicality of the method of the present invention.

[0060] Example 2: This embodiment provides a minimum reactive power compensation capacity calculation system for asynchronous machine loads, used to implement the minimum reactive power compensation capacity calculation method as described in Embodiment 1.

[0061] Example 3: like Figure 8 As shown, this embodiment provides an electronic device, which may include: at least one processor, at least one network interface, a user interface, a memory, and at least one communication bus.

[0062] The communication bus can be used to enable communication between the various components mentioned above.

[0063] The user interface may include buttons, and optional user interfaces may also include standard wired interfaces and wireless interfaces.

[0064] The network interface may include, but is not limited to, Bluetooth modules, NFC modules, Wi-Fi modules, etc.

[0065] The processor may include one or more processing cores. It connects various parts of the electronic device via various interfaces and lines, executing instructions, programs, code sets, or instruction sets stored in memory, and accessing data stored in memory to perform various functions and process data. Optionally, the processor can be implemented using at least one hardware form of DSP, FPGA, or PLA. The processor may integrate one or more of the following: CPU, GPU, and modem. The CPU primarily handles the operating system, user interface, and applications; the GPU is responsible for rendering and drawing the content required for display; and the modem handles wireless communication. It is understood that the modem may also be implemented as a separate chip without being integrated into the processor.

[0066] The memory may include RAM or ROM. Optionally, the memory may include a non-transitory computer-readable medium. The memory can be used to store instructions, programs, code, code sets, or instruction sets. The memory may include a program storage area and a data storage area, wherein the program storage area may store instructions for implementing an operating system, instructions for at least one function (such as touch function, sound playback function, image playback function, etc.), instructions for implementing the above-described method embodiments, etc.; the data storage area may store data involved in the above-described method embodiments, etc. Optionally, the memory may also be at least one storage device located remotely from the aforementioned processor. The memory, as a computer storage medium, may include an operating system, a network communication module, a user interface module, and computing applications. The processor can be used to call the computing applications stored in the memory and execute the steps of the minimum reactive power compensation capacity calculation method mentioned in the foregoing embodiments.

[0067] Example 4: This embodiment provides a computer-readable storage medium storing instructions that, when executed on a computer or processor, cause the computer or processor to perform the above-described instructions. Figure 1 One or more steps in the illustrated embodiment. If the constituent modules of the above-described electronic device are implemented as software functional units and sold or used as independent products, they can be stored in the computer-readable storage medium.

[0068] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented in software, it can be implemented, in whole or in part, as a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this specification are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in or transmitted through a computer-readable storage medium. The computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, Digital Subscriber Line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium accessible to a computer or a data storage device such as a server or data center that integrates one or more available media. The available media may be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., Digital Versatile Discs (DVDs)), or semiconductor media (e.g., Solid State Disks (SSDs)).

[0069] Those skilled in the art will understand that all or part of the processes in the method of Embodiment 1 described above can be implemented by a computer program instructing related hardware. This program can be stored in a computer-readable storage medium, and when executed, it can include the processes of the embodiments of the methods described above. The aforementioned storage medium includes various media capable of storing program code, such as ROM, RAM, magnetic disks, or optical disks. Unless otherwise specified, the technical features of this embodiment and the implementation scheme can be combined arbitrarily.

[0070] It should be noted that, for the sake of simplicity, the foregoing method embodiments are all described as a series of actions. However, those skilled in the art should understand that the present invention is not limited to the described order of actions, because according to the present invention, some steps can be performed in other orders or simultaneously. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to the present invention.

[0071] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0072] The above description is merely an exemplary embodiment of the present invention and should not be construed as limiting the scope of the invention. Any equivalent changes and modifications made in accordance with the teachings of this invention are still within the scope of this invention. Those skilled in the art will readily conceive of embodiments of the invention upon considering the specification and practicing the disclosure herein. This invention is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not described herein. The specification and embodiments are to be considered exemplary only, and the scope and spirit of the invention are defined by the claims.

Claims

1. A method for calculating the minimum reactive power compensation capacity of an asynchronous machine load, characterized in that, Including the following steps: S1. Derive analytical expressions for electromagnetic torque, active power, and reactive power based on the steady-state equivalent circuit model of an asynchronous motor. S2. Obtain the given electromagnetic torque and substitute it into the analytical expression of electromagnetic torque derived in step S1 to solve for the corresponding slip rate. S3. Substitute the slip obtained in step S2 into the analytical expressions of active power and reactive power derived in step S1. Starting from the preset voltage, gradually reduce the voltage with a preset step size, calculate the active power and reactive power corresponding to each voltage value point by point, and draw the voltage-active power characteristic curve and voltage-reactive power characteristic curve based on the calculation results. S4. Determine the critical minimum voltage for transient voltage stability of the asynchronous motor based on the voltage-active power characteristic curve plotted in step S3. S5. From the voltage-reactive power characteristic curve drawn in step S3, extract the reactive power value corresponding to the critical minimum voltage determined in step S4, and use the reactive power value as the minimum reactive power compensation capacity required to maintain the stable operation of the asynchronous machine.

2. The method for calculating the minimum reactive power compensation capacity of an asynchronous machine load according to claim 1, characterized in that: The rotor-side parameters of the steady-state equivalent circuit model have been converted to the stator-side parameters; The parameters of the steady-state equivalent circuit model include stator resistance, stator reactance, rotor equivalent resistance, rotor equivalent reactance, magnetizing reactance, and slip.

3. The method for calculating the minimum reactive power compensation capacity of an asynchronous machine load according to claim 1, characterized in that, The analytical expression for electromagnetic torque derived in step S1 is as follows: ， In the formula, Electromagnetic power, Stator-side phase voltage, The rotor equivalent resistance, For stator resistance, For stator reactance, For rotor equivalent reactance, For slippage, To synchronize mechanical angular velocity.

4. The method for calculating the minimum reactive power compensation capacity of an asynchronous machine load according to claim 1, characterized in that: In step S1, when deriving the analytical expressions for active power and reactive power, the steady-state equivalent circuit is subjected to Thevenin equivalence to obtain the Thevenin equivalent circuit model. Based on the Thevenin equivalent circuit model, analytical expressions for the active power and reactive power are derived.

5. The method for calculating the minimum reactive power compensation capacity of an asynchronous machine load according to claim 4, characterized in that, The analytical expressions for the active power and reactive power are as follows: ， ， In the formula, Stator-side phase voltage, The active equivalent resistance is the resistance of the rotor circuit and the excitation branch connected in parallel. For stator resistance, This is the reactive equivalent reactance after the excitation reactance and rotor leakage reactance are connected in parallel. This refers to the stator reactance.

6. The method for calculating the minimum reactive power compensation capacity of an asynchronous machine load according to claim 1, characterized in that, In step S3: The preset voltage is 1.05 times the per-unit value of the rated voltage; The preset step size is 0.01 times the per-unit value of the rated voltage.

7. The method for calculating the minimum reactive power compensation capacity of an asynchronous machine load according to claim 1, characterized in that, The method for determining the critical minimum voltage in step S4 is as follows: In the voltage-active power characteristic curve, the voltage value corresponding to the lowest point of the curve is taken as the critical minimum voltage for transient voltage stability of the asynchronous machine.

8. A system for calculating the minimum reactive power compensation capacity of an asynchronous machine load, characterized in that, This is used to implement the minimum reactive power compensation capacity calculation method as described in any one of claims 1 to 7.

9. A computer device, the computer device comprising a memory, a processor, and a computer program, characterized in that, When the computer program is executed by the processor, it implements the minimum reactive power compensation capacity calculation method as described in any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the minimum reactive power compensation capacity calculation method as described in any one of claims 1 to 7.

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