Correction calculation method for rigid water hammer turbine model coefficient

Abstract

According to the correction calculation method for the rigid water hammer turbine model coefficient, the flow coefficient of the water turbine is defined by rated working condition parameters according to the concept of a water head of the water turbine, the flow is rewritten into a function of the guide vane opening degree and the water head of the water turbine, and the problem that the flow measurement difficulty of a hydropower station is large is solved; establishing a water turbine linearization model by adopting a water turbine output equation recommended by IEEE Working Group, and constructing an increment linearization model from the guide vane opening to the water turbine output in combination with a water turbine flow linearization equation; the influence of pipeline hydraulic loss is introduced into a rigid water attack transfer function, a water turbine output transfer function model under the pipeline rigid water attack is established, the model has the same form as a PSD-BPA water turbine model of the China University of Electricity, and a model correction coefficient can be directly calculated, so that the parameter calculation of the model is simplified, and the application is convenient.

Description

Technical Field

[0001] The invention relates to the technical field of turbine parameter calculation, and in particular to a correction calculation method for rigid water hammer turbine model coefficients. Background Art

[0002] The calculation of power system flow requires the calculation of the electromechanical transient process of the hydro-generator set. To avoid the dimensional disaster, the hydraulic system and turbine model usually adopts a first-order transfer function model from the guide vane opening to the turbine power, which only considers the rigid water hammer of the pipeline. However, it is found in the application that this model is closely related to the initial operating conditions. Since the model was originally defined based on the initial operating condition head and flow as the base value, the relevant parameters, including the only parameter in the model, the water flow inertia time coefficient, are not suitable for the calculation of power system flow flow. It is also defined by the initial operating parameters. The turbine power linearization model is based on = Derived based on QH, assuming power coefficient when normalizing It is a constant. The stable operation area of ​​traditional turbines is generally above 60% of rated power, and the area of ​​transient analysis calculation is mostly around 80% of rated power. The error caused by approximating Kp as a constant is not large. In power system analysis, the parameters of 80%-90% rated power are directly used to define the linear model parameters. In this case, the per-unit processing based on the initial operating head and flow as the base value has certain errors and has not attracted enough attention. Although the corresponding correction coefficient is given in the PSD-BPA of the China Electric Power Research Institute, most of the actual applications are simplified to the ideal turbine model.

[0003] With the construction of new power systems, hydropower units serve as large-capacity regulating power sources, and wide-load operation and regulation have become their new missions. When operating in medium and low power areas that are far from the rated power, large errors will occur when using the ideal turbine model to calculate the turbine power, which will lead to relatively large errors when more finely analyzing the governor performance and primary frequency regulation characteristics. For this reason, some engineering researchers have conducted research on the correction of the PSD-BPA turbine linearization model. The current research mainly starts from the measured data and analyzes and gives the corresponding correction method. Due to the influence of factors such as the operation site of the hydropower station and the changes in upstream and downstream water levels, this correction method based on measured data has a large workload and has certain limitations in terms of universality for complex operating conditions of the unit. Summary of the Invention

[0004] In view of this, the present invention proposes a correction calculation method for the rigid water hammer turbine model coefficient to solve the problem described in the background technology.

[0005] The technical solution of the present invention is achieved as follows: A method for calculating the correction of a rigid water hammer turbine model coefficient comprises the following steps: Step S1: Based on the definition of turbine head, the turbine discharge coefficient is obtained using rated operating parameters, and the discharge coefficient is rewritten as a function of the guide vane opening and the turbine head; Step S2: linearize the function of the guide vane opening and the turbine head at a given operating point, and obtain a transfer function model from the guide vane opening to the volute end head in combination with the pipeline hydraulic transient; Step S3: obtaining the steady-state power of the turbine of the nonlinear turbine model and performing linearization processing, and deriving an incremental linearization model of the guide vane opening to the turbine power in combination with the pipeline hydraulic transient; Step S4: introducing pipeline hydraulic loss into the pipeline rigid water hammer model, and deriving a modified turbine power calculation model and an analytical calculation expression of the correction coefficient; Step S5: Calculate the rated head no-load operating parameters, turbine gain coefficient, flow coefficient, and pipeline hydraulic loss function.

[0006] Preferably, the specific steps of step S1 include: Step S11: Simplify the turbine flow section into equivalent flow elements, and establish the Bernoulli equation for the turbine inlet and outlet sections: = ; in 、 are the elevations of the measuring points at the turbine inlet and outlet sections, 、 are the water pressure at the turbine inlet and outlet sections, 、 are the cross-sectional areas of the turbine inlet and outlet, respectively. 、 are the turbine inlet and outlet correction coefficients, is the acceleration due to gravity, For traffic, is the guide vane opening, is the hydraulic loss coefficient of the flow section of the turbine; Step S12: Define turbine head is the unit energy difference of the turbine inlet and outlet sections, and the flow rate is obtained The expression: ; in is the flow coefficient, which is expressed as ; Step S13: The expression is rewritten into relative value form to obtain the function of guide vane opening and turbine head: ; in , 、 as well as Flow , flow coefficient , Rated guide vane opening and turbine head The relative value form.

[0007] Preferably, the turbine head The expression is: = .

[0008] Preferably, the specific steps of step S2 include: Step S21: Perform Taylor expansion on the function of the guide vane opening and the turbine head at the initial operating point, ignoring the second-order and higher-order terms, to obtain the first linearized form equation: ; in They are and The corresponding values ​​under the initial working conditions are: is the relative value of the guide vane opening under the initial working condition, is the guide vane opening increment; Step S22: Obtain the transfer function of the head increment and flow increment in the pipeline hydraulic transient state : ; in is the head increment, is the transfer function, is the flow increment; Step S23: multiply both sides of the first linearized form equation by the transfer function The transfer function model from the guide vane opening to the water head at the end of the volute is obtained: .

[0009] Preferably, the specific steps of step S3 include: Step S31: Obtain the steady-state power of the nonlinear turbine model: ; in is the steady-state power of the turbine, is the turbine gain coefficient, It is the relative value of no-load flow; Step S32: Perform Taylor expansion on the calculation formula of the turbine steady-state power at the initial operating point, and ignore the second-order and higher-order terms to obtain the second linearized form equation: ; is the flow rate under initial conditions The relative value of Step S33: Substitute the first linearized equation into the second linearized equation, and use the transfer function model from the guide vane opening to the volute end head to eliminate the flow variable that is difficult to measure, thereby obtaining the incremental linearized model from the guide vane opening to the turbine power: .

[0010] Preferably, the specific steps of step S4 include: Step S41: In the transfer function Adding the friction loss head, the rigid water hammer model taking into account the hydraulic loss of the pipeline is obtained as follows: ; in is the water flow inertia time constant defined under rated operating conditions, is the Laplace operator, is the pipeline friction loss coefficient in relative terms; Step S42, take = , and rewrite the incremental linearization model from guide vane opening to turbine power: ; in .

[0011] Preferably, the expression of the water flow inertia time constant is: ; in is the acceleration due to gravity, is the pipe length, and They are the rated flow and rated head respectively.

[0012] Preferably, the specific steps of calculating the rated head no-load operating condition parameters in step S5 are: The rated power output of any water head is near the high efficiency area. Assuming that the efficiency is approximately equal, there is ≈ , , rewriting the function of guide vane opening and turbine head to obtain: ; Assume that the water flow energy required to drive the unit to reach the no-load rated speed under any water head and rated water head is equal, that is , the no-load flow is small and the hydraulic loss is small, approximately is the no-load running head under rated head, is the no-load running head under any head, and the function of the guide vane opening and turbine head can be obtained as follows: ; No-load point parameters under rated head It is a constant that does not change with the operating conditions. Two points near the rated output are selected from the measured data. Assume that the coefficient Approximately equal, obtain The expression is: .

[0013] Preferably, the specific steps of calculating the turbine gain coefficient and the flow coefficient in step S5 are: Incorporating power generation efficiency into the coefficient In the turbine gain coefficient, for: ; The function of guide vane opening and turbine head, turbine gain coefficient Substituting this into the steady-state power of the nonlinear turbine model, we obtain: ; Transform the above formula to get: .

[0014] Preferably, the specific steps of calculating the pipeline hydraulic loss function in step S5 are: Get an alternative definition of the head at the end of a pipe: ; Transient head under steady-state conditions , select two points of measured data near the rated output, and calculate the pipeline hydraulic loss function based on the following formula: .

[0015] Compared with the prior art, the present invention has the following beneficial effects: The application is a correction calculation method of rigid water hammer hydraulic turbine model coefficient, and belongs to the technical field of stability analysis and speed control of hydraulic turbine. According to the concept of water head of hydraulic turbine, the flow coefficient of hydraulic turbine is defined by the rated working condition parameters, and is rewritten as a function of guide vane opening and water head of hydraulic turbine, so as to avoid the problem of difficult flow measurement of hydropower station. Then, under the linearization of given working condition point, the transfer function model of guide vane opening to the water head at the end of the spiral case is obtained by combining the pipe hydraulic transient, the uncertainty caused by the change of initial working condition is reduced, the incremental linearization model of hydraulic turbine is obtained by using the hydraulic turbine model recommended by IEEE Working Group, and the influence of the change of power coefficient with working condition is eliminated. Finally, the influence of pipe hydraulic loss is introduced into the rigid water hammer transfer function, so as to obtain higher calculation accuracy, so as to establish the output transfer function model of hydraulic turbine under the pipe rigid water hammer. The model has the same form as the PSD-BPA hydraulic turbine model of China Electric Power Research Institute, the model correction coefficient can be directly obtained, so as to solve the difficulty of obtaining accurate correction coefficient under the complex working condition of hydropower unit operation. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only preferred embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor.

[0017] Figure 1 The flow chart of the correction calculation method of rigid water hammer hydraulic turbine model coefficient of the application is shown in the figure. Figure 2 The PSD-BPA mixed flow hydraulic turbine model (TV) is shown in the figure. Figure 3 The measured data of hydropower station unit is shown in the figure. Figure 4 The coefficient The curve graph of the change of guide vane opening. Figure 5 The measured guide vane opening change curve is shown in the figure. Figure 6 The output active power comparison graph is shown in the figure. DETAILED DESCRIPTION

[0018] The technical solution of the present invention is further elaborated in detail below in conjunction with the drawings and specific embodiments of the specification. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention. In the following description, reference is made to "some embodiments", which describes a subset of all possible embodiments, but it should be understood that "some embodiments" can be the same subset or different subsets of all possible embodiments, and can be combined with each other without conflict.

[0019] See also Figure 1 The present invention provides a method for calculating the correction of the rigid water hammer turbine model coefficient, comprising the following steps: Step S1: Based on the definition of turbine head, the turbine discharge coefficient is obtained using rated operating parameters, and the discharge coefficient is rewritten as a function of the guide vane opening and the turbine head; The specific steps include: Step S11: Simplify the turbine flow section into equivalent flow elements, and establish the Bernoulli equation for the turbine inlet and outlet sections: = ; in 、 are the elevations of the measuring points at the turbine inlet and outlet sections, 、 are the water pressure at the turbine inlet and outlet sections, 、 are the cross-sectional areas of the turbine inlet and outlet, respectively. 、 are the turbine inlet and outlet correction coefficients, is the acceleration due to gravity, For traffic, is the opening area of ​​the flow element, which is equivalent to the opening area of ​​the guide vane, that is, the guide vane opening. is the hydraulic loss coefficient of the flow section of the turbine; Step S12: Strictly define the turbine head is the unit energy difference of the turbine inlet and outlet sections, and the flow rate is obtained The expression: ; in is the flow coefficient, which is expressed as ; is the turbine head, and its expression is = ; flow This valve-like situation, according to the classical hydraulic theory, shows that the hydraulic loss coefficient of different opening degrees is It changes nonlinearly, and the hydraulic loss coefficient It is difficult to determine the exact value of . Engineering practice shows that the head loss coefficient at the valve It is mainly related to the valve opening, and here it is regarded as a single-valued function related to the guide vane opening. express; Step S13: Using rated operating parameters is the base value, where is the rated head, is the rated flow rate, is the rated guide vane opening. The guide vane opening used by the hydropower station governor is the relative opening: Assume that the guide vane opening base value is , relative opening ,Pick , the flow The expression is rewritten into relative value form to obtain the function of guide vane opening and turbine head: ; in , 、 as well as Flow , flow coefficient , Rated guide vane opening and turbine head The relative value form.

[0020] Step S2: linearize the function of the guide vane opening and the turbine head at a given operating point, and obtain a transfer function model from the guide vane opening to the volute end head in combination with the pipeline hydraulic transient; The specific steps include: Step S21: Taylor expansion is performed on the function of the guide vane opening and the turbine head at the initial operating point, ignoring the second-order and higher-order terms. The linearized form is: ; The first linearized form equation can be obtained: ; The subscript "0" in the formula represents the corresponding value of each parameter under the initial working condition, where They are and The corresponding values ​​under the initial working conditions are: is the relative value of the guide vane opening under the initial working condition, is the guide vane opening increment; The turbine inlet pressure is approximately equal to the volute pressure or the steel pipe end pressure, and the runner outlet pressure is equal to the draft tube inlet pressure. When the guide vane adjustment range is not large, the draft tube inlet pressure fluctuation range is also small, and the turbine head increment ∆ h t It can be approximated as the increment of volute pressure, and its physical meaning is the same as the transient water pressure increment ∆ h They are consistent and approximately equal in the incremental sense, and pipeline hydraulic transients can be introduced.

[0021] Step S22: Obtain the transfer function of the head increment and flow increment in the pipeline hydraulic transient state : ; in is the head increment, is the transfer function, is the flow increment; Step S23: multiply both sides of the first linearized form equation by the transfer function The transfer function model from the guide vane opening to the water head at the end of the volute is obtained: .

[0022] Step S3: linearize the steady-state power of the turbine using the nonlinear turbine model recommended by the IEEE Working Group, and derive an incremental linearization model from the guide vane opening to the turbine power in combination with the pipeline hydraulic transients; The specific steps include: Step S31: Obtain the steady-state power of the nonlinear turbine model: ; in is the steady-state power of the turbine, is the turbine gain coefficient, It is the relative value of no-load flow; Step S32: Perform Taylor expansion on the calculation formula of the turbine steady-state power at the initial operating point, and ignore the second-order and higher-order terms to obtain the second linearized form equation: ; is the flow rate under initial conditions The relative value of Step S33: Substitute the first linearized equation into the second linearized equation, and use the transfer function model from the guide vane opening to the volute end head to eliminate the flow variable that is difficult to measure, thereby obtaining the incremental linearized model from the guide vane opening to the turbine power: .

[0023] The rigid water hammer transfer function model is derived by ignoring the friction loss head in the pipeline. This leads to errors after the guide vane adjustment reaches steady state. Including the friction loss head in the transfer function can achieve higher calculation accuracy.

[0024] Step S4: introducing pipeline hydraulic loss into the pipeline rigid water hammer model, and deriving a modified turbine power calculation model and an analytical calculation expression of the correction coefficient; The specific steps include: Step S41: In the transfer function Adding the friction loss head, the rigid water hammer model taking into account the hydraulic loss of the pipeline is obtained as follows: ; in is the Laplace operator, It is the relative value of the pipeline friction loss coefficient, which is only related to the structural characteristic parameters of the hydraulic system and does not change with the system working conditions. is the water flow inertia time constant defined under rated operating conditions. Its value does not change with operating conditions. Its expression is: ; in is the acceleration due to gravity, is the pipe length, and They are rated flow and rated head respectively; Step S42, take = , and rewrite the incremental linearization model from guide vane opening to turbine power: ; in .

[0025] The Francis turbine model (TV) given in the PSD-BPA software of China Electric Power Research Institute is shown in the attached figure. Figure 2 As shown, compared with the incremental linearization model of the present invention, the form is consistent, Figure 2 in Corresponding to the incremental linearization model The BPA model provides correction curves for guide vane opening and power at different water heads. These curves correspond to the coefficient K of the incremental linearization model. The BPA correction curves and coefficients a and b require data from hydropower station field tests to establish the opening-power relationship curve and coefficients a and b. The incremental linearization model provides calculation expressions for each coefficient, theoretically resolving this issue.

[0026] Step S5: Calculate the rated head no-load operating parameters, turbine gain coefficient, flow coefficient, and pipeline hydraulic loss function. The specific steps are as follows: The flow measurement is difficult in the test of giant hydro-generator sets. The parameter calculation tries to avoid the flow calculation. The rated power output of any water head is near the high efficiency area. Assuming that the efficiency is approximately equal, there is ≈ , , rewriting the function of guide vane opening and turbine head to obtain: ; Assume that the water flow energy required to drive the unit to reach the no-load rated speed under any water head and rated water head is equal, that is , the no-load flow is small and the hydraulic loss is small, approximately is the no-load running head under rated head, is the no-load running head under any head, and the function of the guide vane opening and turbine head can be obtained as follows: ; No-load point parameters under rated head It is a constant that does not change with the operating conditions. Two points near the rated output are selected from the measured data. Assume that the coefficient Approximately equal, obtain The expression is: .

[0027] Incorporating power generation efficiency into the coefficient In the turbine gain coefficient, for: ; According to the above definition, the turbine gain coefficient Does not change with the water head, it can be calculated according to the above formula , the function of guide vane opening and turbine head, turbine gain coefficient Substituting this into the steady-state power of the nonlinear turbine model, we obtain: ; Transform the above formula to get: .

[0028] Using the measured data of generator power, guide vane opening and water head, the The initial operating point is calculated based on the guide vane opening difference as the guide vane opening curve changes. .

[0029] Another definition of the head at the end of the pipe is: ; Transient head under steady-state conditions , select two points of measured data near the rated output, and calculate the pipeline hydraulic loss function based on the following formula: .

[0030] After obtaining the various parameters of the turbine model, the transient changes in turbine power under different guide vane openings can be simulated and calculated.

[0031] The present invention provides a correction calculation method for the coefficient of the rigid water hammer turbine model, which is mainly used in the field of stability analysis and control design of the hydropower unit regulation system and has important engineering application significance. First, based on the concept of turbine head, the turbine flow coefficient is defined with the rated operating condition parameters, and the flow is rewritten as a function of the guide vane opening and the turbine head. This avoids the problem of difficult flow measurement in hydropower stations and reduces the uncertainty caused by changes in initial operating conditions. Then, based on the fact that the turbine head increment is consistent with the pipeline hydraulic transient water pressure increment, the pipeline hydraulic transient is introduced, and a transfer function from the guide vane opening to the volute end head is established. The IEEE Working The turbine treatment equation recommended by the Group is used to establish a turbine linearization model. Combined with the turbine flow linearization equation, an incremental linearization model from the guide vane opening to the turbine treatment is constructed to eliminate the influence of the power coefficient changing with the operating conditions, and solve the error caused by the flow coefficient deviating from the rated operating conditions in the traditional derivation method. At the same time, the influence of pipeline hydraulic loss is introduced into the rigid water hammer transfer function, and a turbine output transfer function model under pipeline rigid water hammer is established. The composition of the turbine model correction coefficient is given in the form of an analytical expression, which solves the difficulty of obtaining accurate correction coefficients under complex operating conditions of hydropower units. In addition to being applied to the PSD-BPA turbine model, this model is also used in the design of turbine speed governor control strategies, primary frequency regulation performance analysis, etc., with high calculation accuracy. Finally, after calculating the basic parameters of the turbine model based on the measured data, various simulation calculations and control design calculations can be performed.

[0032] In order to verify the effect of the present invention, the data of a hydropower station are used for calculation: The guide vanes of a hydropower station unit are continuously adjusted, and the guide vane opening, generator power, and volute inlet pressure are measured. ), tailwater pipe pressure ( ), as attached Figure 3 shown.

[0033] Based on measured data, the values ​​for power, guide vane opening, volute water pressure, and draft tube inlet water pressure within the full power range are read and formed into an array to calculate the required characteristic parameters. This step can also be calculated using full-load operating data from the unit stability test.

[0034] Select three points near the rated operating point, take two points of data respectively, and press The expression of calculating the no-load point parameter and taking the mean value is obtained. =0.1021.

[0035] According to the calculation formula of turbine gain coefficient, we can get =1.1137.

[0036] According to the calculation formula of flow coefficient, calculate the flow rate under different guide vane openings. , fitting The curve of the change of the guide vane opening is shown in the attached figure. Figure 4 shown.

[0037] Select two points of measured data near the rated output and calculate according to the pipeline hydraulic loss function =0.0171.

[0038] After obtaining the various parameters of the turbine model, the transient changes in turbine power under different guide vane openings can be simulated and calculated.

[0039] Select Attachment Figure 3 The first section 30s-120s is calculated based on the measured data. The measured guide vane opening changes are shown in the attached figure. Figure 5 Taking the measured guide vane opening change as input, a simulation system is established to calculate the output power of the turbine model of the present invention. The changes in the simulated and measured unit power output are shown in the attached figure. Figure 6 shown.

[0040] Attachment Figure 6 It shows that the unit output power calculated by the present invention has a high calculation accuracy compared with the actual measured power.

[0041] The above description is only a preferred embodiment of the present invention and is not intended to limit 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. A method for calculating the coefficient of a rigid water hammer turbine model, characterized in that: The following steps are involved: Step S1: Based on the definition of turbine head, the turbine discharge coefficient is obtained using rated operating parameters, and the discharge coefficient is rewritten as a function of the guide vane opening and the turbine head; Step S2: linearize the function of the guide vane opening and the turbine head at a given operating point, and obtain a transfer function model from the guide vane opening to the volute end head in combination with the pipeline hydraulic transient; Step S3: obtaining the steady-state power of the turbine of the nonlinear turbine model and performing linearization processing, and deriving an incremental linearization model of the guide vane opening to the turbine power in combination with the pipeline hydraulic transient; Step S4: introducing pipeline hydraulic loss into the pipeline rigid water hammer model, and deriving a modified turbine power calculation model and an analytical calculation expression of the correction coefficient; Step S5: Calculate the rated head no-load operating parameters, turbine gain coefficient, flow coefficient, and pipeline hydraulic loss function.

2. The method for correcting and calculating the coefficient of a rigid water hammer turbine model according to claim 1, characterized in that: The specific steps of step S1 include: Step S11: Simplify the turbine flow section into equivalent flow elements, and establish the Bernoulli equation for the turbine inlet and outlet sections: = ； in 、 are the elevations of the measuring points at the turbine inlet and outlet sections, 、 are the water pressure at the turbine inlet and outlet sections, 、 are the cross-sectional areas of the turbine inlet and outlet, respectively. 、 are the turbine inlet and outlet correction coefficients, is the acceleration due to gravity, For traffic, is the guide vane opening, is the hydraulic loss coefficient of the flow section of the turbine; Step S12: Define turbine head is the unit energy difference of the turbine inlet and outlet sections, and the flow rate is obtained The expression: ； in is the flow coefficient, which is expressed as ; Step S13: The expression is rewritten into relative value form to obtain the function of guide vane opening and turbine head: ； in , 、 as well as Flow , flow coefficient , Rated guide vane opening and turbine head The relative value form.

3. The method for correcting and calculating the coefficient of a rigid water hammer turbine model according to claim 2, characterized in that: The turbine head The expression is: = 。 4. The method for correcting and calculating the coefficient of a rigid water hammer turbine model according to claim 2, wherein: The specific steps of step S2 include: Step S21: Perform Taylor expansion on the function of the guide vane opening and the turbine head at the initial operating point, ignoring the second-order and higher-order terms, to obtain the first linearized form equation: ； in They are and The corresponding values ​​under the initial working conditions are: is the relative value of the guide vane opening under the initial working condition, is the guide vane opening increment; Step S22: Obtain the transfer function of the head increment and flow increment in the pipeline hydraulic transient state : ； in is the head increment, is the transfer function, is the flow increment; Step S23: multiply both sides of the first linearized form equation by the transfer function The transfer function model from the guide vane opening to the water head at the end of the volute is obtained: 。 5. The method for correcting and calculating the coefficient of a rigid water hammer turbine model according to claim 4, characterized in that: The specific steps of step S3 include: Step S31: Obtain the steady-state power of the nonlinear turbine model: ； in is the steady-state power of the turbine, is the turbine gain coefficient, It is the relative value of no-load flow; Step S32: Perform Taylor expansion on the calculation formula of the turbine steady-state power at the initial operating point, and ignore the second-order and higher-order terms to obtain the second linearized form equation: ； is the flow rate under initial conditions The relative value of Step S33: Substitute the first linearized equation into the second linearized equation, and use the transfer function model from the guide vane opening to the volute end head to eliminate the flow variable that is difficult to measure, thereby obtaining the incremental linearized model from the guide vane opening to the turbine power: 。 6. The method for correcting and calculating the coefficient of a rigid water hammer turbine model according to claim 5, characterized in that: The specific steps of step S4 include: Step S41: In the transfer function Adding the friction loss head, the rigid water hammer model taking into account the hydraulic loss of the pipeline is obtained as follows: ； in is the water flow inertia time constant defined under rated operating conditions, is the Laplace operator, is the pipeline friction loss coefficient in relative terms; Step S42, take = , and rewrite the incremental linearization model from guide vane opening to turbine power: ； in .

7. A method for calculating the correction of rigid water hammer turbine model coefficients according to claim 6, characterized in that: The expression of the water flow inertia time constant is: ； in is the acceleration due to gravity, is the pipe length, and They are the rated flow and rated head respectively.

8. The method for calculating the correction of the rigid water hammer turbine model coefficient according to claim 6, characterized in that: The specific steps for calculating the rated water head no-load working condition parameters in step S5 are: The rated power output of any water head is near the high efficiency area. Assuming that the efficiency is approximately equal, there is ≈ , , rewriting the function of guide vane opening and turbine head to obtain: ； Assume that the water flow energy required to drive the unit to reach the no-load rated speed under any water head and rated water head is equal, that is , the no-load flow is small and the hydraulic loss is small, approximately is the no-load running head under rated head, is the no-load running head under any head, and the function of the guide vane opening and turbine head can be obtained as follows: ； No-load point parameters under rated head It is a constant that does not change with the operating conditions. Two points near the rated output are selected from the measured data. Assume that the coefficient Approximately equal, obtain The expression is: 。 9. A method for calculating the correction of rigid water hammer turbine model coefficients according to claim 8, characterized in that: The specific steps of calculating the turbine gain coefficient and the flow coefficient in step S5 are as follows: Incorporating power generation efficiency into the coefficient In the turbine gain coefficient, for: ； The function of guide vane opening and turbine head, turbine gain coefficient Substituting this into the steady-state power of the nonlinear turbine model, we obtain: ； Transform the above formula to get: 。 10. A method for calculating the correction of rigid water hammer turbine model coefficients according to claim 9, characterized in that: The specific steps of calculating the pipeline hydraulic loss function in step S5 are: Get an alternative definition of the head at the end of a pipe: ； Transient head under steady-state conditions , select two points of measured data near the rated output, and calculate the pipeline hydraulic loss function based on the following formula: 。

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