Analysis method and system for transient voltage instability of induction motor load considering large disturbance

Abstract

The present invention discloses a method and system for analyzing transient voltage instability of an induction motor load considering large disturbances, and relates to the technical field of power grid safety control. The key points of the technical solution are: analyzing the influence of electromagnetic transient processes on the speed drop of the induction motor under large disturbance impact, and estimating the speed drop caused by the electromagnetic transient process; calculating the slip rate of the induction motor at the time of fault clearing according to the duration of the short-circuit fault; analyzing the influence of the induction motor on the transient voltage level during the system recovery process according to the sensitivity relationship between the transient voltage after the system fault and the slip rate of the induction motor, and obtaining the voltage drop of each node; analyzing the influence of the induction motor load recovery process on the system transient voltage recovery time based on the voltage drop of each node, and obtaining the transient voltage recovery time. The present invention can make a relatively accurate estimate of the influence of the induction motor on the impact of a large disturbance fault of a large power grid without performing large-scale electromagnetic transient analysis and calculation.

Description

Technical Field

[0001] The present invention relates to the technical field of power grid safety control, and more specifically, to a method and system for analyzing transient voltage instability of an induction motor load considering large disturbances. Background Art

[0002] In the context of "dual carbon", as the proportion of clean energy increases, the electrical distance between the clean energy grid connection point and the load center is long, and the conventional power supply of the load center is growing slowly, showing the characteristics of "power hollowing out". One of the direct consequences of "power hollowing out" is that transient voltage instability dominated by the dynamics of induction motor loads has become a key factor restricting the power supply capacity of the power grid.

[0003] After research, it was found that under large disturbance impacts, the electromagnetic transient processes of the power network and the stator and rotor of the induction motor have a significant impact on the transient voltage stability level. However, the electromechanical transient model or steady-state model used in traditional large power grid analysis cannot take into account the electromagnetic transient processes of the power network and the stator of the induction motor, which often leads to significant errors in the voltage instability analysis dominated by the dynamics of the induction motor, resulting in insufficient conservatism in the boundary verification of the power grid operation, which brings great safety risks to the power grid.

[0004] Therefore, how to study and design an induction motor load transient voltage instability analysis method and system that can overcome the above-mentioned defects and take large disturbances into consideration is a problem that we urgently need to solve. Summary of the invention

[0005] In order to address the deficiencies in the prior art, the purpose of the present invention is to provide a method and system for analyzing transient voltage instability of induction motor loads taking large disturbances into account, which can make a relatively accurate estimate of the impact of large disturbance faults on induction motors without performing large-scale electromagnetic transient analysis calculations, and play a guiding role in the transient voltage stability analysis in power grids with a high proportion of clean energy.

[0006] The above technical objectives of the present invention are achieved through the following technical solutions:

[0007] In a first aspect, a method for analyzing transient voltage instability of an induction motor load considering large disturbances is provided, comprising the following steps:

[0008] Analyze the impact of electromagnetic transient process on the speed drop of induction motor under large disturbance impact, and estimate the speed drop caused by electromagnetic transient process;

[0009] The induction motor slip rate at the moment of fault clearing is calculated by combining the speed drop caused by the electromagnetic transient process and the short-circuit fault duration;

[0010] According to the sensitivity relationship between the transient voltage after the system fault and the slip rate of the induction motor, the influence of the induction motor on the transient voltage level during the system recovery process is analyzed, and the voltage drop of each node is obtained;

[0011] Based on the voltage drop conditions at each node, the influence of the induction motor load recovery process on the system transient voltage recovery time is analyzed to obtain the transient voltage recovery time.

[0012] Furthermore, the speed drop calculation formula caused by the electromagnetic transient process is specifically as follows:

[0013]

[0014] Where, Δs e It indicates the slip change caused by electromagnetic transient process, and the speed drop is reflected by the slip change; ω0 indicates the rated angular frequency of the power frequency; Im(·) indicates the complex imaginary part operator; (·) * represents the conjugate operator of complex numbers; T j Indicates the rotor inertia time constant; L 10 Indicates the stator winding leakage reactance value; L 20 Indicates the rotor winding leakage reactance value; Ψ 10 Represents the initial value of stator flux; Ψ 20 represents the initial value of the rotor flux; r1 represents the stator winding resistance of the induction motor; r2 represents the initial value of the rotor winding resistance.

[0015] Furthermore, the calculation formula of the induction motor slip rate at the time of fault clearing is specifically:

[0016]

[0017] Among them, s mi Indicates the slip rate of the induction motor when the fault is cleared; T flt Indicates the short circuit fault duration.

[0018] Furthermore, the analysis and acquisition process of the node voltage drop condition is specifically as follows:

[0019] Solve the electrical network power flow equation in the initial state to obtain the initial voltage, initial phase angle, initial current and initial power factor angle of each power source;

[0020] Calculate the internal potential and internal potential phase angle of the power supply according to the initial voltage, initial phase angle, initial current, initial power factor angle and the magnitude of the power supply subtransient reactance;

[0021] Calculate the equivalent impedance based on the slip drop of the induction motor;

[0022] Calculate the node voltage drop based on the equivalent impedance.

[0023] Furthermore, the analysis and acquisition process of the transient voltage recovery time is specifically as follows:

[0024] Calculate the system Thevenin equivalent reactance and open circuit voltage of the induction motor access point based on the voltage drop at each node;

[0025] Calculate the electromagnetic torque of an induction motor;

[0026] Determine whether the induction motor reaches the stability limit based on the electromagnetic torque and mechanical torque of the induction motor;

[0027] If the stability limit is not reached, the transient voltage recovery time is calculated by calculus based on the electromagnetic torque and mechanical torque of the induction motor.

[0028] Furthermore, the electromagnetic torque calculation formula of the induction motor is specifically as follows:

[0029]

[0030] Among them, T ei (s i ) represents the induction motor i at slip rate s i Electromagnetic torque under X 1i Represents the equivalent reactance of the induction motor on the stator side, r 1i Represents the equivalent resistance of the stator winding; X mi represents the excitation reactance; X 2i represents the rotor equivalent reactance; r 2i Represents the rotor equivalent resistance; Z si represents the Thevenin equivalent reactance; E si represents the Thevenin equivalent internal potential; s mi Indicates the induction motor slip rate when the fault is cleared.

[0031] Furthermore, the calculation formula of the transient voltage recovery time is specifically:

[0032]

[0033] Among them, t ri Indicates transient voltage recovery time; s ri Indicates the minimum recoverable slip rate of induction motor i, which is determined by the system low-voltage load reduction setting; s mi Indicates the slip rate of the induction motor when the fault is cleared; T mi represents the mechanical torque of induction motor i; T ei (s i ) represents the induction motor i at slip rate s i The electromagnetic torque under T j Represents the rotor inertia time constant.

[0034] Secondly, a transient voltage instability analysis system for induction motor load considering large disturbances is provided, including:

[0035] The speed analysis module is used to analyze the impact of electromagnetic transient processes on the speed drop of the induction motor under large disturbance impacts, and estimate the speed drop caused by the electromagnetic transient process;

[0036] The slip analysis module is used to calculate the slip rate of the induction motor at the moment of fault clearing by combining the speed drop caused by the electromagnetic transient process and the short-circuit fault duration;

[0037] The voltage analysis module is used to analyze the impact of the induction motor on the transient voltage level during system recovery based on the sensitivity relationship between the transient voltage after the system failure and the induction motor slip rate, and obtain the voltage drop of each node;

[0038] The recovery analysis module is used to analyze the impact of the induction motor load recovery process on the system transient voltage recovery time based on the voltage drop situation of each node, and obtain the transient voltage recovery time.

[0039] In a third aspect, a computer terminal is provided, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the method for analyzing transient voltage instability of an induction motor load taking into account large disturbances as described in any one of the first aspects is implemented.

[0040] In a fourth aspect, a computer-readable medium is provided, on which a computer program is stored, and the computer program is executed by a processor to implement the method for analyzing transient voltage instability of an induction motor load considering large disturbances as described in any one of the first aspects.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] The present invention provides an induction motor load transient voltage instability analysis method considering large disturbances. Since there is a large time scale difference between the electromagnetic transient process and the mechanical transient process, the speed variable can be approximately considered to be approximately unchanged during the electromagnetic transient process, thereby making the induction motor degenerate into a linear model. The contribution of the rotor electromagnetic transient and the stator electromagnetic transient to the speed change can be calculated respectively. Without performing large-scale electromagnetic transient analysis calculations, a relatively accurate estimate can be made of the impact of large disturbance faults on the induction motor. This has a guiding role in the transient voltage stability analysis in power grids with a high proportion of clean energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings:

[0044] Figure 1 It is the flowchart in Embodiment 1 of the present invention;

[0045] Figure 2 It is a system block diagram of Embodiment 2 of the present invention. DETAILED DESCRIPTION

[0046] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0047] Example 1: Analysis method of transient voltage instability of induction motor load considering large disturbances, such as Figure 1 As shown, it is specifically implemented by the following steps.

[0048] Step 1: Analyze the impact of the electromagnetic transient process on the speed drop of the induction motor under large disturbance impact, and estimate the speed drop caused by the electromagnetic transient process.

[0049] 1. Obtain the working point of the induction motor before the fault, and measure the following physical quantities of the induction motor: steady-state active power P0; steady-state reactive power Q0; steady-state voltage amplitude U0.

[0050] 2. According to the initial operating state of the induction motor, analyze and calculate the initial values ​​of the state variables of the induction motor, and calculate the initial primary and secondary side flux and slip rate of the induction motor.

[0051] (1) Calculate the initial value of stator current:

[0052]

[0053] Among them, I 10 represents the initial current value of the induction motor stator, and j represents an imaginary unit.

[0054] (2) Calculate the initial value of the stator flux of the induction motor:

[0055] Ψ 10 =-jU0+jr1I 10

[0056] Among them, 10 It represents the initial value of stator flux, and r1 represents the stator winding resistance of the induction motor.

[0057] (3) Calculate the initial value of the induction motor rotor current:

[0058]

[0059] Among them, I 20represents the initial value of the rotor current, M represents the excitation reactance value of the induction motor, L 10 Indicates the stator winding leakage reactance value.

[0060] (4) Calculate the initial value of the induction motor rotor flux:

[0061] Ψ 20 =MI 10 +(M+L 20 )I 20

[0062] Ψ 20 is the initial value of the rotor flux, L 20 is the rotor winding leakage reactance value.

[0063] (5) Calculate the initial value of the slip rate:

[0064]

[0065] Among them, s0 represents the initial value of the slip rate, and r2 represents the initial value of the rotor winding resistance.

[0066] 3. Calculate the impact of electromagnetic transient process on the speed drop of induction motor. The speed drop caused by electromagnetic transient process can be estimated according to the following formula:

[0067]

[0068] Among them, Δs e It indicates the slip change caused by electromagnetic transient process, and the speed drop is reflected by the slip change; ω0 indicates the rated angular frequency of the power frequency; Im(·) indicates the complex imaginary part operator; (·) * represents the conjugate operator of complex numbers; T j Indicates the rotor inertia time constant; L 10 Indicates the stator winding leakage reactance value; L 20 Indicates the rotor winding leakage reactance value; Ψ 10 Represents the initial value of stator flux; Ψ 20 represents the initial value of the rotor flux; r1 represents the stator winding resistance of the induction motor; r2 represents the initial value of the rotor winding resistance.

[0069] Step 2: Calculate the induction motor slip rate at the moment of fault clearing by combining the speed drop caused by the electromagnetic transient process and the short-circuit fault duration.

[0070] In order to distinguish the slip change caused by electromagnetic transients from that caused by mechanical processes, the slip rate of the induction motor at the time of fault clearing is calculated according to the duration of the short-circuit fault. The calculation formula of the slip rate of the induction motor at the time of fault clearing is as follows:

[0071]

[0072] Among them, s mi Indicates the slip rate of the induction motor when the fault is cleared; T flt Indicates the short circuit fault duration.

[0073] Step 3: According to the sensitivity relationship between the transient voltage after the system failure and the induction motor slip rate, the influence of the induction motor on the transient voltage level during the system recovery process is analyzed to obtain the voltage drop of each node.

[0074] 1. Solve the electrical network power flow equation in the initial state and obtain the initial voltage U of each power supply i , initial phase angle θ i , initial current I i , initial power factor angle φ i .

[0075] 2. According to the power supply subtransient reactance X″ di Calculate the potential E″ in the power supply di and the internal potential phase angle δ i , the calculation method is:

[0076]

[0077] Where j is the imaginary unit, is the internal potential phasor,

[0078] 3. Calculate the equivalent impedance based on the slip drop of the induction motor:

[0079]

[0080] Among them, X 1i is the equivalent reactance of the induction motor on the stator side, r 1i is the stator winding equivalent resistance, X mi is the magnetizing reactance, X 2i is the rotor equivalent reactance, r 2i is the rotor equivalent resistance.

[0081] Z loadi =Z statici +Z mi

[0082] Among them, the load equivalent impedance Z loadi is the static impedance Z of load point i statici Add the equivalent impedance Z of the induction motor mi .

[0083] 4. Calculate the node voltage drop:

[0084]

[0085] Where: Y grid is the node admittance matrix of the power grid, are the voltage and current phasors of the nodes.

[0086] Substituting the power supply and load characteristics, by solving the linear equations, we can solve

[0087] Step 4: Analyze the impact of the induction motor load recovery process on the system transient voltage recovery time based on the voltage drop conditions at each node, and obtain the transient voltage recovery time.

[0088] 1. Calculate the system Thevenin equivalent reactance and open circuit voltage at the induction motor i access point:

[0089] In the network admittance matrix Y grid The equivalent impedance to ground of the remaining loads j (j≠i) is added by the branch addition method, according to Z in step 3. loadj (j≠i) Consider, we get Y gridi , and based on Y gridi , Calculate the Thevenin equivalent reactance Z at the load connection point si and the equivalent internal potential E si .

[0090] 2. Obtain the electromagnetic torque T of the induction motor i ei (s i ) is the analytical expression:

[0091]

[0092] Among them, s i is the independent variable, and is the slip rate of induction motor i.

[0093] 3. Determine whether the induction motor can be recovered (whether it has reached the stability limit), the criteria are:

[0094] T ei (s mi )>T mi

[0095] Among them, T mi is the mechanical torque of motor i.

[0096] 4. If the stability limit is reached, the voltage can be determined to be unstable; if the stability limit is not reached, the transient voltage recovery time t can be calculated ri The calculation method is as follows: i The definite integral of :

[0097]

[0098] Among them, sri is the minimum recoverable slip rate of motor i, which is determined by the system low-voltage load reduction setting.

[0099] Take the squirrel cage induction motor as an example, its parameters are: r1 = 0.02pu, L 10 =0.18pu, r2=0.02pu, L 20 =0.12pu, M=3.499pu.

[0100] Rotor inertia time constant T j =2s, P0=0.945pu, Q0=0.58pu, U0=1p.u.

[0101] Machine-side fault duration T flt =0.2s.

[0102] 1. Calculate the initial state of the induction motor:

[0103]

[0104] Ψ 10 =-j+jr1I 10 =0.0116-j0.9811 pu

[0105]

[0106] Ψ 20 =MI 10 +(M+L 20 )I 20 =-0.2773-j0.8372 pu

[0107]

[0108] (2) Calculate the impact of electromagnetic transient process on slip rate:

[0109]

[0110]

[0111] The comparison results are shown in Table 1:

[0112] Table 1 Comparison results of slip rate changes

[0113]

[0114] It can be seen from Table 1 that the difference value calculated by the method proposed in the present invention is very close to the electromagnetic transient analysis result, which fully demonstrates the correctness of the analysis conclusion.

[0115] Embodiment 2: A system for analyzing transient voltage instability of an induction motor load considering large disturbances, the system is used to implement the method for analyzing transient voltage instability of an induction motor load considering large disturbances recorded in Embodiment 1, such as Figure 2 As shown, it includes a speed analysis module, a slip analysis module, a voltage analysis module and a recovery analysis module.

[0116] Among them, the speed analysis module is used to analyze the impact of the electromagnetic transient process on the speed drop of the induction motor under large disturbance impact, and to estimate the speed drop caused by the electromagnetic transient process; the slip analysis module is used to calculate the slip rate of the induction motor at the moment of fault clearing by combining the speed drop caused by the electromagnetic transient process and the short-circuit fault duration; the voltage analysis module is used to analyze the impact of the induction motor on the transient voltage level during the system recovery process based on the sensitivity relationship between the transient voltage after the system fault and the induction motor slip rate, and obtain the voltage drop situation of each node; the recovery analysis module is used to analyze the impact of the induction motor load recovery process on the system transient voltage recovery time based on the voltage drop situation of each node, and obtain the transient voltage recovery time.

[0117] Working principle: The method for analyzing transient voltage instability of induction motor load considering large disturbances provided by the present invention is based on the large time scale difference between electromagnetic transient process and mechanical transient process. Therefore, the speed variable can be approximately considered to be approximately unchanged during the electromagnetic transient process, thereby making the induction motor degenerate into a linear model. The contribution of rotor electromagnetic transient and stator electromagnetic transient to the speed change can be calculated respectively. Without performing large-scale electromagnetic transient analysis and calculation, a relatively accurate estimate can be made of the impact of large disturbance faults on the induction motor in the large power grid, which has a guiding role in the transient voltage stability analysis in power grids with a high proportion of clean energy.

[0118] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0119] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0120] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0121] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process in the computer or other programmable device. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0122] The above specific implementation methods further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above are only specific implementation methods of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. The method for analyzing transient voltage instability of induction motor load considering large disturbances is characterized by: The following steps are involved: Analyze the impact of electromagnetic transient process on the speed drop of induction motor under large disturbance impact, and estimate the speed drop caused by electromagnetic transient process; The induction motor slip rate at the moment of fault clearing is calculated by combining the speed drop caused by the electromagnetic transient process and the short-circuit fault duration; According to the sensitivity relationship between the transient voltage after the system fault and the slip rate of the induction motor, the influence of the induction motor on the transient voltage level during the system recovery process is analyzed, and the voltage drop of each node is obtained; Based on the voltage drop of each node, the influence of the induction motor load recovery process on the system transient voltage recovery time is analyzed to obtain the transient voltage recovery time; The analysis and acquisition process of the node voltage drop condition is specifically as follows: Solve the electrical network power flow equation in the initial state to obtain the initial voltage, initial phase angle, initial current and initial power factor angle of each power source; Calculate the internal potential and internal potential phase angle of the power supply according to the initial voltage, initial phase angle, initial current, initial power factor angle and the magnitude of the power supply subtransient reactance; Calculate the equivalent impedance based on the slip drop of the induction motor; Calculate the node voltage drop based on equivalent impedance; The specific calculation formula for the speed drop caused by the electromagnetic transient process is: Among them, Δs e It indicates the slip change caused by electromagnetic transient process, and the speed drop is reflected by the slip change; ω0 indicates the rated angular frequency of the power frequency; Im(·) indicates the complex imaginary part operator; (·) * represents the conjugate operator of complex numbers; T j Indicates the rotor inertia time constant; L 10 Indicates the stator winding leakage reactance value; L 20 Indicates the rotor winding leakage reactance value; Ψ 10 Represents the initial value of stator flux; Ψ 20 represents the initial value of the rotor flux; r1 represents the stator winding resistance of the induction motor; r2 represents the initial value of the rotor winding resistance; The calculation formula of the induction motor slip rate at the fault clearing moment is specifically: Among them, s mi Indicates the slip rate of the induction motor when the fault is cleared; T flt Indicates the short circuit fault duration.

2. The method for analyzing transient voltage instability of an induction motor load considering large disturbances according to claim 1 is characterized in that: The analysis and acquisition process of the transient voltage recovery time is specifically as follows: Calculate the system Thevenin equivalent reactance and open circuit voltage of the induction motor access point based on the voltage drop at each node; Calculate the electromagnetic torque of an induction motor; Determine whether the induction motor reaches the stability limit based on the electromagnetic torque and mechanical torque of the induction motor; If the stability limit is not reached, the transient voltage recovery time is calculated by calculus based on the electromagnetic torque and mechanical torque of the induction motor.

3. The method for analyzing transient voltage instability of an induction motor load considering large disturbances according to claim 2 is characterized in that: The electromagnetic torque calculation formula of the induction motor is specifically: Among them, T ei (s i ) represents the induction motor i at slip rate s i Electromagnetic torque under X 1i Represents the equivalent reactance of the induction motor on the stator side, r 1i Represents the equivalent resistance of the stator winding; X mi represents the excitation reactance; X 2i represents the rotor equivalent reactance; r 2i Represents the rotor equivalent resistance; Z si represents the Thevenin equivalent reactance; E si represents the Thevenin equivalent internal potential; s mi Indicates the induction motor slip rate when the fault is cleared.

4. The method for analyzing transient voltage instability of an induction motor load considering large disturbances according to claim 2 is characterized in that: The calculation formula of the transient voltage recovery time is specifically: Among them, t ri Indicates transient voltage recovery time; s ri Indicates the minimum recoverable slip rate of induction motor i, which is determined by the system low-voltage load reduction setting; s mi Indicates the slip rate of the induction motor when the fault is cleared; T mi represents the mechanical torque of induction motor i; T ei (s i ) represents the induction motor i at slip rate s i Electromagnetic torque under j Represents the rotor inertia time constant.

5. The transient voltage instability analysis system of induction motor load considering large disturbance is characterized by: The system is used to implement the method for analyzing transient voltage instability of an induction motor load considering large disturbances as described in any one of claims 1 to 4, comprising: The speed analysis module is used to analyze the impact of electromagnetic transient processes on the speed drop of the induction motor under large disturbance impacts, and estimate the speed drop caused by the electromagnetic transient process; The slip analysis module is used to calculate the slip rate of the induction motor at the moment of fault clearing by combining the speed drop caused by the electromagnetic transient process and the short-circuit fault duration; The voltage analysis module is used to analyze the impact of the induction motor on the transient voltage level during system recovery based on the sensitivity relationship between the transient voltage after the system failure and the induction motor slip rate, and obtain the voltage drop of each node; The recovery analysis module is used to analyze the impact of the induction motor load recovery process on the system transient voltage recovery time based on the voltage drop situation of each node, and obtain the transient voltage recovery time.

6. A computer terminal comprising a memory, a processor and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the program, the method for analyzing transient voltage instability of an induction motor load considering large disturbances as described in any one of claims 1 to 4 is implemented.

7. A computer readable medium having a computer program stored thereon, characterized in that: The computer program is executed by a processor to implement the method for analyzing transient voltage instability of an induction motor load considering large disturbances as described in any one of claims 1 to 4.

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