Torsional vibration response analysis method and system of steam turbine generator shaft system, storage medium and electronic equipment

Abstract

The invention relates to a torsional vibration response analysis method and system for a steam turbine generator shaft system, a storage medium and electronic equipment. The torsional vibration response analysis method comprises the following steps that different torsional vibration working conditions of the steam turbine generator shaft system are determined; the torsional vibration response of the steam turbine generator shaft system is calculated based on different torsional vibration working conditions, and torsional vibration response data of the steam turbine generator shaft system are obtained; calculating the electromagnetic torque of the steam turbine generator; the steam moment of the steam turbine generator is calculated; and comprehensively analyzing the torsional vibration response of the steam turbine generator shaft system according to the torsional vibration data, the electromagnetic torque and the steam torque under different working conditions. The torsional vibration response of the shaft system of the steam turbine generator unit can be analyzed and calculated, and a basis is provided for analyzing the influence of power grid fluctuation on shaft vibration of a steam turbine generator of a nuclear power plant.

Description

Technical Field

[0001] The present invention relates to the technical field of steam turbine generator vibration analysis, and more specifically, to a method, system, storage medium and electronic equipment for analyzing the torsional vibration response of a steam turbine generator shaft system. Background Art

[0002] During operation, the steam turbine generator set may be subject to various electrical disturbances from outside the unit, such as power grid fluctuations, short circuit faults, abnormal operating conditions such as loss of excitation of the unit, and operations such as missynchronization and line reclosing. Among them, the most typical is the power grid fluctuations near the power plant or at the generator end. During the duration of the fluctuation, a relatively severe transient torque impact will be generated on the shaft system of the unit. The main shaft may not break directly, but it will cause fatigue life operation, shorten the effective service life, and seriously affect the safe and stable operation of the unit.

[0003] The generator units of a certain generator manufacturer generally have the problem of sudden vibration of the generator during power grid fluctuations or start-up and shutdown, which is a common technical problem. When the power grid is disturbed, the vibration of the generator often exceeds the limit for a short time, seriously affecting the status monitoring of the unit, and it is common. The torsional vibration analysis of the shaft system of the steam turbine generator set is an important part of the safety assessment of the steam turbine. Therefore, it is necessary to analyze the torsional vibration response of the shaft system of the steam turbine generator set when facing external disturbances such as power grid fluctuations. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a method, system, storage medium and electronic equipment for analyzing the torsional vibration response of a turbine generator shaft system in view of the problems existing in the prior art.

[0005] The technical solution adopted by the present invention to solve the technical problem is to construct a torsional vibration response analysis method of a steam turbine generator shaft system, comprising the following steps:

[0006] Determine different torsional vibration conditions of the turbine generator shaft system;

[0007] Calculating the torsional vibration response of the steam turbine generator shaft system based on the different torsional vibration working conditions to obtain torsional vibration response data of the steam turbine generator shaft system;

[0008] Calculate the electromagnetic torque of the steam turbine generator;

[0009] calculating the steam torque of the steam turbine generator;

[0010] The torsional vibration response of the turbine generator shaft system is comprehensively analyzed based on the torsional vibration data under the different working conditions, the electromagnetic torque and the steam torque.

[0011] In the torsional vibration response analysis method of the turbine generator shaft system described in the present invention, the different torsional vibration conditions include: any one of a low-order torsional vibration condition, a torsional vibration condition with multiple frequency components in a low-frequency band, a high-order vibration condition, and a nonlinear vibration condition;

[0012] If the torsional vibration condition of the steam turbine generator shaft system is a low-order torsional vibration condition or a torsional vibration condition with multiple frequency components in a low-frequency band, then the torsional vibration response of the steam turbine generator shaft system is calculated based on the different torsional vibration conditions to obtain the torsional vibration response data of the steam turbine generator shaft system, including:

[0013] The torsional vibration response of the turbine generator shaft system is calculated by using a modal superposition method to obtain torsional vibration response data under the low-order torsional vibration condition or multi-frequency components in a low-frequency band;

[0014] If the torsional vibration condition of the steam turbine generator shaft system is a high-order vibration condition or a nonlinear vibration condition, then the torsional vibration response of the steam turbine generator shaft system is calculated based on the different torsional vibration conditions to obtain the torsional vibration response data of the steam turbine generator shaft system, including:

[0015] The torsional vibration response of the turbine generator shaft system is calculated by using the Newmark step-by-step integration method to obtain the torsional vibration response data under the high-order vibration condition or nonlinear vibration condition.

[0016] In the method for analyzing the torsional vibration response of the shaft system of a steam turbine generator according to the present invention, the torsional vibration response of the shaft system of the steam turbine generator is calculated by using the modal superposition method to obtain the torsional vibration response data under the low-order torsional vibration condition or the low-frequency band multi-frequency components, which includes:

[0017] Decouple the equations of the torsional vibration system to obtain multiple independent second-order equations;

[0018] The multiple independent second-order equations are solved to obtain the steam turbine generator shaft system and each-order response; the each-order response of the steam turbine generator shaft system is the torsional vibration response data under the low-order torsional vibration condition or the low-frequency band multi-frequency components.

[0019] In the method for analyzing the torsional vibration response of the shaft system of a steam turbine generator according to the present invention, the torsional vibration response of the shaft system of the steam turbine generator is calculated by using the Newmark stepwise integration method to obtain the torsional vibration response data under the high-order vibration condition or nonlinear vibration condition, which includes:

[0020] Determine expressions for angular acceleration and angular velocity;

[0021] Determine initial conditions;

[0022] Perform calculation based on the expression of the angular acceleration, the expression of the angular velocity and the initial condition to obtain an effective stiffness matrix;

[0023] Calculating based on the effective stiffness matrix to obtain response data per unit time; the response data per unit time includes: effective load per unit time increment, angular displacement per unit time increment, angular velocity per unit time increment, and angular acceleration per unit time increment;

[0024] The response data per unit time is torsional vibration response data under the high-order vibration condition or nonlinear vibration condition.

[0025] In the method for analyzing the torsional vibration response of a steam turbine generator shaft system of the present invention, the calculation of the electromagnetic torque of the steam turbine generator includes:

[0026] Obtaining a preliminary expression for the transient electromagnetic torque of the steam turbine generator;

[0027] Transforming the preliminary expression of transient electromagnetic torque to obtain expressions of rotor shaft current and winding axis angle;

[0028] According to the condition that the voltage at the damping winding terminal is zero, the transient voltage expression is obtained;

[0029] The transient voltage expression is substituted into the rotor shaft current and winding axis angle expressions to obtain the electromagnetic torque of the steam turbine generator.

[0030] In the torsional vibration response analysis method of the turbine generator shaft system of the present invention, the preliminary expression for obtaining the transient electromagnetic torque of the turbine generator includes:

[0031] The Parker equation is used to describe the model of the steam turbine generator, and a preliminary expression of the transient electromagnetic torque of the steam turbine generator is obtained.

[0032] In the torsional vibration response analysis method of the steam turbine generator shaft system of the present invention, the calculation of the steam torque of the steam turbine generator includes:

[0033] The preliminary expression of steam torque in steady state is obtained by deducing the balance between steam torque and electromagnetic torque in steady-state operation of steam turbine generator;

[0034] Determine different types of steam flow rate variations and isentropic energy equations for steam nozzle cascades;

[0035] Substituting the different types of steam flow rate variation equations and the steam nozzle cascade isentropic energy equation into a steady-state mechanical power expression to obtain a steady-state mechanical power output equation;

[0036] Substituting the mechanical power output formula into the preliminary expression of steam torque to obtain steady-state steam torque;

[0037] The steady-state steam torque is multiplied by the torque ratio of each cylinder to obtain the power torque of each cylinder; the power torque of each cylinder is the steam torque of the steam turbine generator.

[0038] The present invention also provides a torsional vibration response analysis system for a turbine generator shaft system, comprising:

[0039] A working condition determination unit, used to determine different torsional vibration working conditions of the turbine generator shaft system;

[0040] a torsional vibration response calculation unit, used to calculate the torsional vibration response of the steam turbine generator shaft system based on the different torsional vibration working conditions, and obtain torsional vibration response data of the steam turbine generator shaft system;

[0041] An electromagnetic torque calculation unit, used to calculate the electromagnetic torque of the steam turbine generator;

[0042] A steam torque calculation unit, used for calculating the steam torque of the steam turbine generator;

[0043] The torsional vibration response analysis unit is used to comprehensively analyze the torsional vibration response of the turbine generator shaft system according to the torsional vibration data under the different working conditions, the electromagnetic torque and the steam torque.

[0044] The present invention also provides a storage medium storing a computer program, wherein the computer program is suitable for being loaded by a processor to execute the steps of the method for analyzing the torsional vibration response of a turbine generator shaft system as described above.

[0045] The present invention also provides an electronic device, comprising a memory and a processor, wherein the memory stores a computer program, and the processor executes the steps of the above-mentioned method for analyzing the torsional vibration response of a steam turbine generator shaft system by calling the computer program stored in the memory.

[0046] The torsional vibration response analysis method, system, storage medium and electronic device of the steam turbine generator shaft system of the present invention have the following beneficial effects: including the following steps: determining different torsional vibration working conditions of the steam turbine generator shaft system; calculating the torsional vibration response of the steam turbine generator shaft system based on different torsional vibration working conditions to obtain torsional vibration response data of the steam turbine generator shaft system; calculating the electromagnetic torque of the steam turbine generator; calculating the steam torque of the steam turbine generator; comprehensively analyzing the torsional vibration response of the steam turbine generator shaft system according to the torsional vibration data, electromagnetic torque and steam torque under different working conditions. The present invention can analyze and calculate the torsional vibration response of the shaft system of the steam turbine generator set, providing a basis for analyzing the influence of power grid fluctuations on the shaft vibration of the steam turbine generator in nuclear power plants. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0048] Figure 1 It is a flow chart of the torsional vibration response analysis method of the turbine generator shaft system provided by the present invention;

[0049] Figure 2 It is the overall logic diagram of the torsional vibration response analysis method of the steam turbine generator shaft system provided by the present invention;

[0050] Figure 3 It is a logic diagram of electromagnetic torque calculation provided by the present invention;

[0051] Figure 4 It is a logic diagram of steam torque calculation provided by the present invention;

[0052] Figure 5 It is a simulation diagram of the calculation of the instantaneous electromagnetic torque of a steam turbine generator when a power grid of a certain power plant is disturbed, provided by the present invention;

[0053] Figure 6 It is a principle block diagram of the torsional vibration response analysis system of the steam turbine generator shaft system provided by the present invention. DETAILED DESCRIPTION

[0054] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0055] refer to Figure 1 , Figure 1 The present invention provides a flow chart of the method for analyzing the torsional vibration response of a turbine generator shaft system.

[0056] Specifically, Figure 1 As shown, the torsional vibration response analysis method of the turbine generator shaft system includes the following steps:

[0057] Step S101: Determine different torsional vibration conditions of the turbine generator shaft system.

[0058] In the embodiment of the present invention, different torsional vibration conditions include: any one of a low-order torsional vibration condition, a torsional vibration condition with multiple frequency components in a low-frequency band, a high-order vibration condition, and a nonlinear vibration condition.

[0059] Step S102: Calculate the torsional vibration response of the steam turbine generator shaft system based on different torsional vibration working conditions to obtain torsional vibration response data of the steam turbine generator shaft system.

[0060] In an embodiment of the present invention, if the torsional vibration condition of the steam turbine generator shaft system is a low-order torsional vibration condition or a torsional vibration condition with multiple frequency components in a low frequency band, the torsional vibration response of the steam turbine generator shaft system is calculated based on different torsional vibration conditions, and obtaining the torsional vibration response data of the steam turbine generator shaft system includes: calculating the torsional vibration response of the steam turbine generator shaft system using a modal superposition method to obtain the torsional vibration response data under low-order torsional vibration conditions or multiple frequency components in a low frequency band.

[0061] If the torsional vibration condition of the steam turbine generator shaft system is a high-order vibration condition or a nonlinear vibration condition, the torsional vibration response of the steam turbine generator shaft system is calculated based on different torsional vibration conditions, and the torsional vibration response data of the steam turbine generator shaft system is obtained, including: using the Newmark step-by-step integration method to calculate the torsional vibration response of the steam turbine generator shaft system, and obtaining the torsional vibration response data under the high-order vibration condition or the nonlinear vibration condition.

[0062] In the embodiment of the present invention, for different torsional vibration conditions, different methods need to be used to calculate the torsional vibration response of the turbine generator shaft system. Among them, the modal superposition method can be used to calculate the torsional vibration response for low-order torsional vibration conditions and torsional vibration conditions with multiple frequency components in the low frequency band, and the Newmark step-by-step integration method can be used to calculate the torsional vibration response for high-order vibration conditions and nonlinear vibration conditions.

[0063] Optionally, in an embodiment of the present invention, the modal superposition method is used to calculate the torsional vibration response of the steam turbine generator shaft system to obtain torsional vibration response data under low-order torsional vibration conditions or multi-frequency components in a low-frequency band, including: decoupling the equations of the torsional vibration system to obtain multiple independent second-order equations; solving the multiple independent second-order equations to obtain the steam turbine generator shaft system and each order response; the each order response of the steam turbine generator shaft system is the torsional vibration response data under low-order torsional vibration conditions or multi-frequency components in a low-frequency band.

[0064] Optionally, in an embodiment of the present invention, the Newmark step-by-step integration method is used to calculate the torsional vibration response of the turbine generator shaft system, and obtaining the torsional vibration response data under high-order vibration conditions or nonlinear vibration conditions includes: determining the expression of angular acceleration and the expression of angular velocity; determining the initial conditions; calculating based on the expression of angular acceleration, the expression of angular velocity and the initial conditions to obtain the effective stiffness matrix; calculating based on the effective stiffness matrix to obtain the response data per unit time; the response data per unit time includes: the effective load per unit time increment, the angular displacement per unit time increment, the angular velocity per unit time increment and the angular acceleration per unit time increment. Among them, the response data per unit time is the torsional vibration response data under high-order vibration conditions or nonlinear vibration conditions.

[0065] Step S103: Calculate the electromagnetic torque of the steam turbine generator.

[0066] In an embodiment of the present invention, calculating the electromagnetic torque of the steam turbine generator includes: obtaining a preliminary expression of the transient electromagnetic torque of the steam turbine generator; transforming the preliminary expression of the transient electromagnetic torque to obtain the expression of the rotor shaft current and the winding axis angle; obtaining the transient voltage expression according to the condition that the voltage at the damping winding terminal is zero; substituting the transient voltage expression into the expression of the rotor shaft current and the winding axis angle to obtain the electromagnetic torque of the steam turbine generator. Among them, obtaining the preliminary expression of the transient electromagnetic torque of the steam turbine generator includes: using the Park equation to describe the model of the steam turbine generator to obtain the preliminary expression of the transient electromagnetic torque of the steam turbine generator.

[0067] Step S104: Calculate the steam torque of the steam turbine generator.

[0068] In an embodiment of the present invention, calculating the steam torque of a steam turbine generator includes: deducing the steam torque and electromagnetic torque balance when the steam turbine generator is in steady-state operation to obtain a preliminary expression of the steam torque in steady state; determining different types of steam flow variation formulas and steam nozzle blade isentropic energy equations; substituting different types of steam flow variation formulas and steam nozzle blade isentropic energy equations into the mechanical power expression in steady state to obtain the mechanical power output formula in steady state; substituting the mechanical power output formula into the preliminary expression of steam torque to obtain the steady-state steam torque. Among them, the steady-state steam torque is multiplied by the torque ratio of each cylinder to obtain the power torque of each cylinder; the power torque of each cylinder is the steam torque of the steam turbine generator. Among them, different types of steam flow variation formulas include: high-pressure cylinder steam flow variation formula and low-pressure cylinder steam flow variation formula. Among them, the high-pressure cylinder steam flow variation formula can be expressed according to the Frugel formula, and the high-pressure cylinder steam flow variation formula can be calculated after ignoring the condenser pressure.

[0069] Step S105: Comprehensively analyzing the torsional vibration response of the turbine generator shaft system according to the torsional vibration data, electromagnetic torque and steam torque under different working conditions.

[0070] It should be noted that, in the embodiment of the present invention, the torsional vibration response data under different torsional vibration conditions, the electromagnetic torque of the steam turbine generator, and the steam torque of the steam turbine generator are three parameters for the torsional vibration response analysis of the steam turbine generator shaft torsional vibration system. The three are calculated independently without any order requirement.

[0071] Specifically, Figure 2 As shown, the torsional vibration response analysis of the shaft system of the steam turbine generator set includes the response calculation of the shaft vibration under different working conditions, the calculation of the electromagnetic torque and the calculation of the steam torque.

[0072] The shaft system of the steam turbine generator (i.e., the shaft system of the steam turbine generator set) runs in a closed state inside the cylinder. If its torsional vibration is measured directly, the measurement means are extremely limited. The rotating shaft system of the steam turbine generator shaft system is essentially a torsional vibration system with low damping characteristics. When the shaft system encounters a torque surge or impact, it will exhibit torsional vibration as a whole. Due to the weak damping of the system, its energy dissipation capacity is poor, resulting in the vibration caused by the known excitation lasting for a long time. Therefore, in order to grasp and analyze the torsional vibration of the shaft system in real time, it is usually necessary to rely on the actual measured disturbance data, i.e., the electromagnetic torque and steam torque, and then analyze and evaluate the torsional vibration response of each section of the shaft system. This process can also be called torsional vibration response analysis. Specifically, the situation in which the torsional vibration system of the steam turbine generator shaft system is disturbed by the outside world can be summarized as follows:

[0073]

[0074] (1) In the formula, J represents the moment of inertia obtained by modeling, C t represents the torsional damping obtained by modeling, K t represents the torsional stiffness matrix, F t represents the disturbance torque.

[0075] The non-diagonal inertia matrix of the turbine generator shaft system has dynamic coupling, and the non-diagonal stiffness matrix has static coupling. Therefore, before using the modal superposition method to calculate the torsional vibration response of the system, it is necessary to decouple the equations of torsional vibration to form multiple (such as n) single-degree-of-freedom independent vibration equations. Among them, the turbine generator shaft system belongs to weak torsional damping, and the decoupled system damping can be approximated as proportional damping, that is:

[0076] C t =aJ+bK t (2).

[0077] (2)In the formula, a and b are constants greater than zero.

[0078] It can be seen from equation (2) that after the damping term in the torsional vibration equation is equivalent to proportional damping, the vibration system can be decoupled according to the undamped case. The system decoupling can be achieved by using the coordinate transformation of the main vibration matrix, and the decoupling equation can be expressed as:

[0079]

[0080] (3) where ψ is the main vibration mode matrix, is the principal coordinate transformation, Q t (t) = ψF t (t) is the generalized force.

[0081] After the system is decoupled, the inertia matrix, damping matrix, and stiffness matrix are all diagonal matrices, and the original vibration system is decoupled into n independent second-order equations, namely:

[0082]

[0083] In equation (4), is the proportional damping coefficient of the i-th order torsional vibration mode, are the responses of each order.

[0084] By solving the principal coordinate equation, the responses of each order of the decoupled equation are obtained Then the response of the system can be obtained by superposition of the principal vibration modes, namely:

[0085]

[0086] In equation (5), represents the torsional vibration angle component at the i-th moment.

[0087] It should be noted that in practical engineering applications, the system accuracy can be improved by refining the modeling, and at the same time, the degrees of freedom of the system can also be increased. Among them, for a linear system, in the case of simple harmonic excitation or a composite excitation composed of simple frequencies, the excitation frequency and the response frequency are basically the same. Due to the corresponding relationship between the excitation and the response in terms of frequency parameters, for the case of simple excitation, the weight of the high-order modes in the calculation of torsional vibration response is relatively low. At this time, there is no obvious difference in the accuracy of the calculated system response whether using full-mode superposition or superposition after truncating some modes. Therefore, by selecting the first r (r < n) order modes for superposition operation, the calculation efficiency can be improved while meeting the accuracy requirements of response calculation. Perform modal reduction on the decoupled equation, and use the first r order modes φ (i) (i = 1, 2,.., r) to form an n×r order truncated modal matrix to calculate the system response, namely:

[0088]

[0089] In the embodiments of the present invention, for high-order vibration conditions or non-linear vibration conditions, the step-by-step integration method is usually used for response analysis. Optionally, the Newmark step-by-step integration method can be selected to calculate the torsional vibration response of the shafting. By selecting appropriate integration parameters, this method is unconditionally stable, and therefore, it can be widely applied to the response analysis of vibration systems.

[0090] First, determine the expressions of angular velocity and angular acceleration.

[0091] Specifically, the angular velocity and angular acceleration of the node at time t+Δt can be expressed as:

[0092]

[0093] (7) In the formula, α and β are integral adjustment parameters, which mainly affect the accuracy and convergence. and When , the Newmark step-by-step integration method is a constant average acceleration method and converges unconditionally; the torsional angular displacement, angular velocity, and angular acceleration of the node at time t are θ t (t)

[0094] Next, give the initial conditions. Set the integration step size Δt, integration parameters α and β; substitute the model's stiffness matrix K t , moment of inertia matrix J and damping matrix C t , calculate the effective stiffness matrix Right now:

[0095]

[0096] Calculate the effective load for a time increment of Δt:

[0097]

[0098] Then calculate the angular displacement at time t+Δt:

[0099]

[0100] Calculate the angular velocity and angular acceleration at time t+Δt:

[0101]

[0102] The Newmark step-by-step integration method is an unconditionally convergent implicit integration. The time step mainly affects the solution accuracy and does not affect the calculation stability. Therefore, this method can be used for online response analysis of impact-type torsional vibration faults or uncertain disturbance forms.

[0103] During the operation of the turbine generator shaft system, it is mainly subjected to steam torque and electromagnetic torque. When the unit is in steady-state operation, the dynamic torque and resistance torque remain stable and balanced, and the torsional deformation of the shaft system is relatively constant. The above-mentioned balance condition of adding stable torque is because in some cases, the dynamic torque and resistance torque are both dynamic torques. Although they meet the balance conditions of equal magnitude and opposite direction, the shaft system is still affected by the dynamic torque and will produce dynamic torsional deformation. The characteristics of electromagnetic torque and steam torque are different, and their action mechanisms and positions on the shaft system are different. During the online monitoring and analysis of torsional vibration, it is necessary to calculate the electromagnetic torque and steam torque online based on the measured information, and then perform response analysis on the shaft system. In actual application, the synchronous generator model is used to numerically calculate the electromagnetic torque, and then the steam torque is calculated using the steady-state torque balance condition.

[0104] In the embodiment of the present invention, the electromagnetic torque of the steam turbine generator is calculated as follows:

[0105] Specifically, Figure 3 As shown:

[0106] First, the synchronous generator model is represented by the fifth-order differential equation described by Parker's equation, using X ad Base value system, then the instantaneous value of the electromagnetic torque of the synchronous motor is T e It can be expressed as:

[0107] T e =ψ d i q -ψ q i d =(-x d i d +x qf I f +x aD I D )i q -(-x q i q +x aQ I Q )i d (9).

[0108] (9) In the formula, x d is the d-axis self-inductance coefficient of the stator winding; x q is the q-axis self-inductance coefficient of the stator winding; x aD is the d-axis mutual inductance; x aQ is the q-axis mutual inductance coefficient; I f is the excitation current; i d 、i q ,I D ,I Q are the currents of the stator winding and damper winding on the vertical and horizontal axes, respectively, and x af =x aD =x ad , x aq =x aQ ; For steam turbine generator, there is x d =x Q .

[0109] The windings of large synchronous generators are all connected in star connection, with zero-axis current i0=0. The basic equation of Parker transformation is as follows:

[0110]

[0111] (10) In the formula, t = nΔt, Δt is the calculation step length, I a ,I b ,Ic is the three-phase current sampling value; θ G It is the angle between the motor rotor d axis and the stator a phase winding axis.

[0112] Assuming that the generator shaft segment torsion angle is θ1, the corresponding electrical angle will change Pθ1. Then, under torsional vibration disturbance, the angle between the motor rotor d axis and the stator a phase winding axis can be expressed as:

[0113]

[0114] (11) Where I m is the phase current amplitude, U m is the phase current amplitude, R a is the internal resistance of the stator winding, is the power factor angle, which can be calculated from the measured a-phase voltage and current sampling values.

[0115] The damping winding current can be ignored in the steady-state operation of the generator, that is, I 1d ,I 1q The initial value is zero. Since the terminal voltage of the damping winding is always zero, the voltage of the transient process can be expressed as:

[0116]

[0117] (12) In the formula, x dd =x d -x1,x 1fd =x ad , x aq =x q -x1, These are the basic parameters of synchronous motors.

[0118] make We can get:

[0119]

[0120] Substitute i d 、i q , let I D ,I Q The initial value is zero, and I can be calculated step by step at time t+Δt. D ,I Q Substituting the above calculation results into formula (9) can calculate the instantaneous value of electromagnetic torque T e .

[0121] When the torsional vibration mode node displaces the generator shaft section, even if the frequency of the disturbing electromagnetic torque is equal to or close to the frequency of a certain order torsional vibration mode, the shaft system will not show obvious resonance or severe torsional vibration response. This is because the generator shaft section can be regarded as a uniform section, and the low-order torsional mode nodes will be distributed in the variable section section or stress concentration section of the shaft system. In fact, the torsional vibration failure of the shaft system is mainly concentrated in the low-order torsional vibration mode, such as the torsional mode included in the subsynchronous frequency band. From this perspective, there are no nodes in the vibration mode of the generator shaft section in the torsional vibration modes of each order in the subsynchronous frequency band of the shaft system, and the vibration mode is relatively straight, which indicates that the torsional angle increment angle of the generator shaft section of the shaft system in the torsional resonance state is small, and the torsional stress of the cross section of the shaft section is also small.

[0122] In order to improve the accuracy, the empirical calculation formula of the electromagnetic torque can be modified, that is, by modifying formula (9), the final expression of the transient electromagnetic torque of the turbine generator shaft system can be obtained as follows:

[0123]

[0124] In the embodiment of the present invention, the calculation of the steam torque of the steam turbine generator is as follows:

[0125] Specifically, Figure 4 As shown in the figure, the steam torque and electromagnetic torque are balanced when the steam turbine generator set is in steady state operation. The steam torque can be derived from the electromagnetic torque:

[0126]

[0127] (13) In the formula, r is the armature resistance, ω e is the steady-state electrical angular velocity, u a0 ,u b0 ,u c0 ,i a0 ,i b0 ,i c0 This is the actual measurement of the three-phase voltage and three-phase current at the generator end before the generator is subjected to torque disturbance.

[0128] T m Multiplying by the torque ratio of each cylinder can get the power torque input to each cylinder. When the steam turbine generator set is in a variable operating state, if the unit operating condition does not change much, its mechanical power output is:

[0129]

[0130] (14) Where N e is the rated power of the unit, ΔH1, ΔH tl It is divided into the ideal enthalpy drop under the rated working condition and the actual working condition of the unit. D is the rated steam flow of the unit, and D l is the actual steam flow rate; ηoe is the rated internal efficiency of the unit, η oel is the actual internal efficiency.

[0131] When the flow area of ​​the steam turbine unit is constant, according to the Flugel formula, the change of steam flow rate in the high-pressure cylinder can be expressed as:

[0132]

[0133] (15) In the formula, P H0 is the rated steam inlet pressure of the corresponding cylinder, P H01 is the measured steam inlet pressure of the corresponding cylinder; P H2 is the rated exhaust pressure of the corresponding cylinder, P H21 is the measured exhaust pressure of the corresponding cylinder, T H0 is the rated steam inlet temperature of the corresponding cylinder, T H01 is the measured steam inlet temperature of the corresponding cylinder.

[0134] For the low-pressure cylinder, due to the lower condenser pressure, P H2 and P H21 The pressure can be ignored, and the steam flow rate of the low-pressure cylinder changes to:

[0135]

[0136] (16) Where D L1 is the actual steam flow rate of the low pressure cylinder, P L01 is the measured intake pressure of the low-pressure cylinder, P L0 is the rated intake pressure of the low-pressure cylinder, T L0 is the rated intake temperature of the low pressure cylinder, T L01 is the measured intake temperature of the low-pressure cylinder.

[0137] When the flow in the steam nozzle cascade is an isentropic process, the energy equation gives:

[0138]

[0139] (17) In the formula, P0 and T0 are the rated pressure and temperature of the corresponding cylinder, respectively. 01 、T 01 are the measured steam pressure and temperature respectively; R s is the adiabatic index of steam, which can be approximated as a constant under steady-state conditions.

[0140] The steam torque of the turbine generator can be expressed as follows through the mechanical output power of the unit:

[0141]

[0142] After obtaining the steam torque of the steam turbine generator through formula (18), the torque exerted by the steam on each stage of the blade (i.e., the power torque of each stage of the cylinder) can be calculated according to the output distribution of the blades of each stage of the steam turbine cylinder (i.e., the torque ratio of each cylinder).

[0143] In the actual torsional vibration monitoring process, the real-time measurement values ​​of the actual measuring points of the unit can be substituted into the calculation.

[0144] Based on the present invention, the electromagnetic torque of the steam turbine generator of a power plant is simulated and analyzed when the power grid is disturbed. The transient electromagnetic torque simulation diagram obtained is as follows: Figure 5 As shown by Figure 5 It can be seen that the analysis effect of the present invention can meet the requirements. Therefore, the present invention can provide a basis for analyzing the influence of power grid fluctuations on the shaft vibration of steam turbine generators, which is of great significance for the safety assessment and unit protection control of steam turbine generators.

[0145] refer to Figure 6 , Figure 6 The present invention provides a schematic diagram of the torsional vibration response analysis system for the turbine generator shaft system.

[0146] like Figure 6 As shown, the torsional vibration response analysis system of the steam turbine generator shaft system includes:

[0147] The operating condition determination unit 601 is used to determine different torsional vibration operating conditions of the turbine generator shaft system.

[0148] The torsional vibration response calculation unit 602 is used to calculate the torsional vibration response of the steam turbine generator shaft system based on different torsional vibration working conditions to obtain the torsional vibration response data of the steam turbine generator shaft system.

[0149] The electromagnetic torque calculation unit 603 is used to calculate the electromagnetic torque of the steam turbine generator.

[0150] The steam torque calculation unit 604 is used to calculate the steam torque of the steam turbine generator.

[0151] The torsional vibration response analysis unit 605 is used to comprehensively analyze the torsional vibration response of the turbine generator shaft system according to the torsional vibration data, electromagnetic torque and steam torque under different working conditions.

[0152] Specifically, the specific coordination operation process between the various units in the torsional vibration response analysis system of the steam turbine generator shaft system here can refer to the above-mentioned torsional vibration response analysis method of the steam turbine generator shaft system, which will not be repeated here.

[0153] In addition, an electronic device of the present invention includes a memory and a processor; the memory is used to store a computer program; the processor is used to execute the computer program to implement the torsional vibration response analysis method of the turbine generator shaft system as any one of the above items. Specifically, according to an embodiment of the present invention, the process described in the above reference flowchart can be implemented as a computer software program. For example, an embodiment of the present invention includes a computer program product, which includes a computer program carried on a computer-readable medium, and the computer program contains a program code for executing the method shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed by an electronic device and when executed, it executes the above functions defined in the method of the embodiment of the present invention. The electronic device in the present invention can be a terminal such as a notebook, a desktop, a tablet computer, a smart phone, or a server.

[0154] In addition, a storage medium of the present invention stores a computer program, and when the computer program is executed by a processor, it implements any of the above methods for analyzing the torsional vibration response of a turbine generator shaft system. Specifically, it should be noted that the above storage medium of the present invention can be a computer-readable signal medium or a computer-readable storage medium or any combination of the above two. The computer-readable storage medium can be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or device, or any combination of the above. More specific examples of computer-readable storage media can include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In the present invention, a computer-readable storage medium can be any tangible medium containing or storing a program, which can be used by or in combination with an instruction execution system, device or device. In the present invention, a computer-readable signal medium can include a data signal propagated in a baseband or as part of a carrier wave, which carries a computer-readable program code. Such propagated data signals may take a variety of forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. Computer readable signal media may also be any computer readable medium other than computer readable storage media, which may send, propagate, or transmit programs for use by or in conjunction with an instruction execution system, apparatus, or device. The program code contained on the computer readable medium may be transmitted using any suitable medium, including but not limited to: wires, optical cables, RF (radio frequency), etc., or any suitable combination of the above.

[0155] The computer-readable medium may be included in the electronic device, or may exist independently without being incorporated into the electronic device.

[0156] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0157] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in the above description according to function. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0158] The steps of the method or algorithm described in conjunction with the embodiments disclosed herein may be implemented directly using hardware, a software module executed by a processor, or a combination of the two. The software module may be placed in a random access memory (RAM), a memory, a read-only memory (ROM), an electrically programmable ROM, an electrically erasable programmable ROM, a register, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

[0159] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot limit the scope of protection of the present invention. All equivalent changes and modifications made to the scope of the claims of the present invention should fall within the scope of the claims of the present invention.

Claims

1. A method for analyzing the torsional vibration response of a turbine generator shaft system, characterized in that: The following steps are involved: Determine different torsional vibration conditions of the turbine generator shaft system; Calculating the torsional vibration response of the steam turbine generator shaft system based on the different torsional vibration working conditions to obtain torsional vibration response data of the steam turbine generator shaft system; Calculate the electromagnetic torque of the steam turbine generator; calculating the steam torque of the steam turbine generator; The torsional vibration response of the turbine generator shaft system is comprehensively analyzed based on the torsional vibration data under the different working conditions, the electromagnetic torque and the steam torque.

2. The method for analyzing torsional vibration response of a turbine generator shaft system according to claim 1, characterized in that: The different torsional vibration conditions include: any one of a low-order torsional vibration condition, a torsional vibration condition with multiple frequency components in a low-frequency band, a high-order vibration condition, and a nonlinear vibration condition; If the torsional vibration condition of the steam turbine generator shaft system is a low-order torsional vibration condition or a torsional vibration condition with multiple frequency components in a low-frequency band, then the torsional vibration response of the steam turbine generator shaft system is calculated based on the different torsional vibration conditions to obtain the torsional vibration response data of the steam turbine generator shaft system, including: The torsional vibration response of the turbine generator shaft system is calculated by using a modal superposition method to obtain torsional vibration response data under the low-order torsional vibration condition or multi-frequency components in a low-frequency band; If the torsional vibration condition of the steam turbine generator shaft system is a high-order vibration condition or a nonlinear vibration condition, then the torsional vibration response of the steam turbine generator shaft system is calculated based on the different torsional vibration conditions to obtain the torsional vibration response data of the steam turbine generator shaft system, including: The torsional vibration response of the turbine generator shaft system is calculated by using the Newmark step-by-step integration method to obtain the torsional vibration response data under the high-order vibration condition or nonlinear vibration condition.

3. The method for analyzing torsional vibration response of a turbine generator shaft system according to claim 2, characterized in that: The method of calculating the torsional vibration response of the turbine generator shaft system by using the modal superposition method to obtain the torsional vibration response data under the low-order torsional vibration condition or the low-frequency band multi-frequency components includes: Decouple the equations of the torsional vibration system to obtain multiple independent second-order equations; The multiple independent second-order equations are solved to obtain the steam turbine generator shaft system and each-order response; the each-order response of the steam turbine generator shaft system is the torsional vibration response data under the low-order torsional vibration condition or the low-frequency band multi-frequency components.

4. The method for analyzing torsional vibration response of a turbine generator shaft system according to claim 2, characterized in that: The method of calculating the torsional vibration response of the turbine generator shaft system by using the Newmark step-by-step integration method to obtain the torsional vibration response data under the high-order vibration condition or the nonlinear vibration condition includes: Determine expressions for angular acceleration and angular velocity; Determine initial conditions; Perform calculation based on the expression of the angular acceleration, the expression of the angular velocity and the initial condition to obtain an effective stiffness matrix; Calculating based on the effective stiffness matrix to obtain response data per unit time; the response data per unit time includes: effective load per unit time increment, angular displacement per unit time increment, angular velocity per unit time increment, and angular acceleration per unit time increment; The response data per unit time is torsional vibration response data under the high-order vibration condition or nonlinear vibration condition.

5. The method for analyzing torsional vibration response of a turbine generator shaft system according to claim 1, characterized in that: The calculation of the electromagnetic torque of the steam turbine generator comprises: Obtaining a preliminary expression for the transient electromagnetic torque of the steam turbine generator; Transforming the preliminary expression of transient electromagnetic torque to obtain expressions of rotor shaft current and winding axis angle; According to the condition that the voltage at the damping winding terminal is zero, the transient voltage expression is obtained; The transient voltage expression is substituted into the rotor shaft current and winding axis angle expressions to obtain the electromagnetic torque of the steam turbine generator.

6. The method for analyzing torsional vibration response of a turbine generator shaft system according to claim 5, characterized in that: The preliminary expression for obtaining the transient electromagnetic torque of the steam turbine generator includes: The Parker equation is used to describe the model of the steam turbine generator, and a preliminary expression of the transient electromagnetic torque of the steam turbine generator is obtained.

7. The method for analyzing torsional vibration response of a turbine generator shaft system according to claim 1, characterized in that: The calculating of the steam torque of the steam turbine generator comprises: The preliminary expression of steam torque in steady state is obtained by deducing the balance between steam torque and electromagnetic torque in steady-state operation of steam turbine generator; Determine different types of steam flow rate variations and isentropic energy equations for steam nozzle cascades; Substituting the different types of steam flow rate variation equations and the steam nozzle cascade isentropic energy equation into a steady-state mechanical power expression to obtain a steady-state mechanical power output equation; Substituting the mechanical power output formula into the preliminary expression of steam torque to obtain steady-state steam torque; The steady-state steam torque is multiplied by the torque ratio of each cylinder to obtain the power torque of each cylinder; the power torque of each cylinder is the steam torque of the steam turbine generator.

8. A torsional vibration response analysis system for a turbine generator shaft system, characterized in that: include: A working condition determination unit, used to determine different torsional vibration working conditions of the turbine generator shaft system; a torsional vibration response calculation unit, used to calculate the torsional vibration response of the steam turbine generator shaft system based on the different torsional vibration working conditions, and obtain torsional vibration response data of the steam turbine generator shaft system; An electromagnetic torque calculation unit, used to calculate the electromagnetic torque of the steam turbine generator; A steam torque calculation unit, used for calculating the steam torque of the steam turbine generator; The torsional vibration response analysis unit is used to comprehensively analyze the torsional vibration response of the turbine generator shaft system according to the torsional vibration data under the different working conditions, the electromagnetic torque and the steam torque.

9. A storage medium, characterized in that: The storage medium stores a computer program, and the computer program is suitable for being loaded by a processor to execute the steps of the method for analyzing the torsional vibration response of a turbine generator shaft system as described in any one of claims 1 to 7.

10. An electronic device, characterized in that: It comprises a memory and a processor, wherein the memory stores a computer program, and the processor executes the steps of the method for analyzing the torsional vibration response of a steam turbine generator shaft system as claimed in any one of claims 1 to 7 by calling the computer program stored in the memory.

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