Semi-physical simulation model test method for transition process of hydropower station

Abstract

The application discloses a kind of semi-physical simulation model test methods of hydropower station transition process, steps include:1) establishing model hydropower station and prototype hydropower station similarity criterion;2) the semi-physical simulation test model of hydropower station transition process is established, and the method of computer real-time simulation is used to test diversion system;Test is carried out using physical model to obtain more accurate internal state in the transition process of hydraulic turbine;3) the semi-physical simulation model test of hydropower station transition process is carried out, and the variation process of the related parameters of prototype hydropower station is calculated back.The method of the application, experimental process is easy to operate, and experimental result accuracy is high.

Description

Technical Field

[0001] This invention belongs to the technical field of hydropower station transition process, and relates to a semi-physical simulation model test method for hydropower station transition process. Background Technology

[0002] Safety accidents at hydropower stations mainly occur during the transition process. Improving the safety of this transition process is crucial for ensuring the overall safety of the hydropower station. Currently, the safety of hydropower stations during the transition process is primarily ensured through calculations. This involves using simulations to obtain changes in water pressure and flow rate at various points in the pipeline system during the transition, thereby assessing the safety of the hydropower station's operation.

[0003] However, due to the complex changes in the internal flow regime of the turbine during the transition process of a hydropower station, it is difficult to consider the detailed changes in the internal fluid of the turbine in the transition process calculation, resulting in large errors in the calculation results. This is particularly evident in pumped storage hydropower stations with high water heads, posing a potential threat to the operational safety of the hydropower station. Summary of the Invention

[0004] The purpose of this invention is to provide a semi-physical simulation model test method for the transient process of a hydropower station, which solves the problem that the existing technology does not adequately consider the internal flow state of the turbine in the calculation of the transient process of a hydropower station, resulting in large errors in the calculation results.

[0005] The technical solution adopted in this invention is a semi-physical simulation model test method for the transient process of a hydropower station, which is implemented according to the following steps:

[0006] Step 1: Establish similarity criteria between the model hydropower station and the prototype hydropower station;

[0007] Step 2: Establish a semi-physical simulation test model of the hydropower station's transient process.

[0008] The water diversion system was tested using real-time computer simulation; physical models were also used to obtain a more accurate understanding of the internal state of the turbine during the transient process.

[0009] Step 3: Conduct a semi-physical simulation model test of the hydropower station's transient process and back-calculate the changes in relevant parameters of the prototype hydropower station.

[0010] The beneficial effects of this invention are that, through theoretical analysis, similarity criteria between the model hydropower station and the prototype hydropower station are obtained. Then, based on the similarity criteria and the characteristics of the hydropower station, a physical model turbine is used to conduct transient process tests, and a real-time computer simulation is used to conduct transient process tests on the water diversion system. Simultaneously, a system consisting of pressure tanks, vacuum tanks, high-pressure tanks, solenoid valves, water pumps, check valves, and other equipment connects the real-time computer simulation system with the physical turbine model system, thus constituting a semi-physical simulation model test method for the transient process of the hydropower station. This invention's method is simple to operate and highly accurate. Attached Figure Description

[0011] Figure 1 This is a block diagram illustrating the experimental principle of the semi-physical simulation model used in the method of this invention;

[0012] Figure 2 This is a schematic diagram of the layout of the prototype hydropower station in the embodiment of the method of the present invention;

[0013] Figure 3 This is a verification result diagram from an embodiment of the method of the present invention.

[0014] In the diagram: 1. High-pressure tank; 2. Solenoid valve one; 3. Pressure tank one; 4. Solenoid valve two; 5. Computer; 6. Solenoid valve three; 7. Pressure tank two; 8. Solenoid valve four; 9. Vacuum tank; 10. Check valve one; 11. Water pump; 12. Measuring device one; 13. Hydraulic turbine unit; 14. Measuring device two; 15. Check valve two. Detailed Implementation

[0015] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0016] The semi-physical simulation model test method for the transient process of a hydropower station according to the present invention is implemented in accordance with the following steps:

[0017] Step 1: Establish similarity criteria between the model hydropower station and the prototype hydropower station.

[0018] Since the model turbine and the prototype turbine have the same unit parameters when operating at similar conditions, therefore:

[0019] In equation (1), n 11 Q is the unit speed of the water turbine. 11 M is the unit flow rate of the water turbine. 11 Here, is the unit torque of the turbine, n is the turbine speed, H is the turbine head, Q is the turbine flow rate, M is the turbine torque, and D is the turbine nominal diameter. Subscript 1 indicates parameters of the model turbine under similar operating conditions, and subscript 2 indicates parameters of the prototype turbine under similar operating conditions. The subscripts in the following expressions... 1,2 And so on.

[0020] The following formula is obtained after transforming formula (1):

[0021]

[0022] In equation (2), it is assumed that the scale ratio between the model turbine and the prototype turbine is D1:D2=1:x D Then equation (2) can be transformed into:

[0023]

[0024] In equation (3), for the water diversion system, based on the rigid water hammer model of the pipeline, the following relationship exists in the water diversion system:

[0025]

[0026] In equation (4), h is the relative value of the turbine head deviation, q is the relative value of the flow deviation, and T w Let t be the inertial time constant of the water flow in the water diversion system, where t is time.

[0027] After another transformation, the expression for the inertial time constant of the water flow is obtained as follows:

[0028]

[0029] In equation (5), L is the length of the water diversion pipe; A is the cross-sectional area of ​​the water diversion pipe; and g is the acceleration due to gravity.

[0030] Since the model hydropower station and the prototype hydropower station operate under similar conditions, after combining equations (4) and (5), we have:

[0031]

[0032] In equation (6), the subscript r This indicates the rated operating condition, and Δ represents the deviation from the initial operating condition.

[0033] Dividing equation (6) by difference and then comparing the two equations, we have:

[0034]

[0035] Since the operating conditions of the model hydropower station are similar to those of the prototype hydropower station, it is further transformed into:

[0036]

[0037] Substituting equation (8) into equation (7), we get:

[0038]

[0039] Assume the size ratio of the model to the prototype of the water diversion system is L1:L2 = 1:x L The time scale of the system transition process is t1:t2 = 1:x t Then the transformed expression of equation (9) is:

[0040]

[0041] Combining equations (3) and (10), we have:

[0042]

[0043] For local head loss, we have:

[0044]

[0045] In equation (12), ξ is the local head loss coefficient, and the subscript is used. J To represent the local head loss, by comparing and rearranging the two equations in equation (12), we get:

[0046]

[0047] To maintain similar operating conditions between the prototype hydropower station and the model hydropower station during dynamic processes, the local head loss in the water diversion system should be consistent with the turbine head ratio. Combining equations (8), (11), and (13), we have:

[0048]

[0049] Regarding the head loss along the pipeline, we have:

[0050]

[0051] In equation (15), λ is the friction head loss coefficient; d is the diameter of the water diversion pipe; subscripts are used to indicate the friction head loss coefficient. Y Indicates head loss along the route,

[0052] Comparing the two equations in equation (15) and rearranging them, we get:

[0053]

[0054] To maintain similar operating conditions between the prototype hydropower station and the model hydropower station during dynamic processes, the head loss along the water diversion system should be consistent with the turbine head ratio. Combining equations (8), (11), and (16), we have:

[0055]

[0056] According to the Chezy-Manning formula, it can be transformed into the following equation:

[0057]

[0058] In equation (18), n c R is the pipe roughness coefficient; R is the pipe hydraulic radius.

[0059] Comparing the two equations in equation (18) and rearranging them, we get:

[0060]

[0061] During the dynamic process of a water turbine, the change in rotational speed must satisfy the following equation of motion:

[0062]

[0063] In equation (20), GD 2 For the flywheel torque of the unit,

[0064] Comparing the two equations in equation (20) and rearranging them, we get:

[0065]

[0066] Combining equations (11) and (21), we have:

[0067]

[0068] The output of the water turbine must satisfy the following expression:

[0069]

[0070] Combining equations (11) and (23), we have:

[0071]

[0072] The expression for water hammer-construction is:

[0073]

[0074] In equation (25), a is the water hammer wave velocity.

[0075] To ensure that the model hydropower station is similar to the prototype hydropower station during dynamic processes, the ratio of water hammer phase to time should be kept consistent. Therefore:

[0076]

[0077] Thus, the similarity criterion between the model hydropower station and the prototype hydropower station is obtained, expressed as:

[0078]

[0079] Step 2: Establish a semi-physical simulation test model of the hydropower station's transient process.

[0080] As can be seen from equation (27), in order to ensure that the transition process of the model hydropower station is similar to that of the prototype hydropower station, there are certain requirements not only for easily controllable parameters such as system size, unit speed, and output, but also for the more difficult-to-control water hammer wave velocity in the pipeline. Considering the characteristics of the large size of the pipeline system, the large variation in the layout of different hydropower stations, and the high simulation accuracy of the pipeline transition process, the water diversion system is tested using real-time computer simulation. Considering the characteristics of the complex internal flow state and relatively small unit size during the turbine transition process, a physical model is used for testing in order to obtain a more accurate internal state of the turbine during the transition process.

[0081] Reference Figure 1 The architecture of the semi-physical simulation test model for the transient process of a hydropower station mainly includes a high-pressure tank 1, a pressure-generating tank 3, a computer 5, a pressure-generating tank 2 7, a vacuum tank 9, and a hydraulic turbine unit 13. High-pressure tank 1 is filled with high-pressure air. Pressure-generating tank 3 contains a mixture of water and air. The top of pressure-generating tank 3 is connected to both solenoid valve 1 2 and solenoid valve 2 4. The other end of solenoid valve 1 2 is connected to high-pressure tank 1, and the other end of solenoid valve 2 4 is connected to the atmosphere or vacuum tank 9. One path from the bottom of pressure-generating tank 3 is connected to the outlet of water pump 11 via a pipe. A check valve 10 is installed at the inlet of water pump 11. Another path from the bottom of pressure-generating tank 3 is connected to the inlet of the spiral casing of hydraulic turbine unit 13. The tailrace of hydraulic turbine unit 13... The pipe end is connected to the bottom of the second pressure tank 7; the second pressure tank 7 also contains some water and some air. The bottom of the second pressure tank 7 is also equipped with a check valve 2 15. The top of the second pressure tank 7 is connected to both a third solenoid valve 6 and a fourth solenoid valve 8. The other end of the third solenoid valve 6 is connected to the atmosphere or the high-pressure tank 1, and the other end of the fourth solenoid valve 8 is connected to the vacuum tank 9. The inlet end of the spiral casing of the hydraulic turbine 13 is equipped with a measuring device 12, and the outlet end of the tailrace pipe of the hydraulic turbine 13 is equipped with a measuring device 2 14. The first measuring device 12 and the second measuring device 2 14 are connected to the signal input terminal of the computer 5. The signal output terminal of the computer 5 is connected to the first solenoid valve 2, the second solenoid valve 4, the third solenoid valve 6, and the fourth solenoid valve 8.

[0082] The working principle of the semi-physical simulation test of the hydropower station transient process is as follows: A mathematical model of the water diversion system is established in computer 5. This mathematical model includes, but is not limited to, solving the pipeline water hammer mathematical model using the method of characteristics, the wave characteristic method, or the analytical function method. The mathematical model includes models of all flow components from the upstream reservoir to the turbine inlet and models of all flow components from the turbine outlet to the downstream river channel. The turbine inlet and turbine outlet are the boundary conditions of this mathematical model.

[0083] The real-time water pressure and flow rate at the turbine inlet are obtained through measuring device 12, and the measured values ​​are transmitted to computer 5. Computer 5 uses the flow rate measured by measuring device 12 as the boundary of the flow component model from the upstream reservoir to the turbine inlet, calculates the real-time water pressure at the turbine inlet, and compares it with the water pressure measured by measuring device 12. When the water pressure measured by measuring device 12 is lower than the calculated real-time water pressure, computer 5 controls solenoid valve 2 to open and solenoid valve 4 to close. At this time, compressed air in high-pressure tank 1 enters pressure tank 3, and check valve 10 closes to prevent water loss in pressure tank 3 and increase the water pressure at the turbine inlet. When the water pressure measured by measuring device 12 is higher than the calculated real-time water pressure, computer 5 controls solenoid valve 2 to close and solenoid valve 4 to open. At this time, compressed air in pressure tank 3 is discharged from pressure tank 3, reducing the water pressure at the turbine inlet, thereby ensuring that the real-time water pressure at the turbine inlet is equal to the calculated water pressure by computer 5.

[0084] Simultaneously, the real-time water pressure and flow rate at the turbine outlet are obtained through measuring device 2 14, and the measured values ​​are transmitted to computer 5. Computer 5 uses the flow rate measured by measuring device 2 14 as the boundary of the flow component model from the turbine outlet to the downstream river channel, calculates the real-time water pressure at the turbine outlet, and compares it with the water pressure measured by measuring device 2 14. When the water pressure measured by measuring device 2 14 is lower than the calculated real-time water pressure, computer 5 controls solenoid valve 3 6 to open and solenoid valve 4 8 to close. At this time, atmospheric air enters pressure tank 2 7 through solenoid valve 3 6, increasing the water pressure value at the turbine outlet. When the water pressure measured by measuring device 2 14 is higher than the calculated real-time water pressure, computer 5 controls solenoid valve 3 6 to close and solenoid valve 4 8 to open. Air in pressure tank 2 7 enters the vacuum tank. At this time, check valve 2 15 closes to prevent tail liquid from entering pressure tank 2, causing pressure reduction failure, thus reducing the water pressure value at the turbine outlet and ensuring that the water pressure at the turbine outlet is equal to the calculated water pressure of computer 5 in real time.

[0085] Step 3: Conduct a semi-physical simulation model test of the hydropower station's transient process.

[0086] 3.1) Solve for the key parameters of the model hydropower station.

[0087] Determine the turbine scale (x) between the prototype hydroelectric power station and the model hydroelectric power station. D Water diversion system scale x L and the transition process time ratio x t Based on equation (27) and relevant parameters of the prototype hydropower station, the length L2 of each water intake pipe of the model hydropower station, the diameter d2 of each water intake pipe of the model hydropower station, the local head loss coefficient ξ2 at each point in the water intake system of the model hydropower station, and the roughness n of each section of the pipe in the water intake system of the model hydropower station were calculated. c2The water hammer wave velocity (a2) of each section of the water diversion system in the model hydropower station; the nominal diameter (D2) of the turbine in the model hydropower station; the head (H2) of the model hydropower station; the flow rate (Q2) of the unit in the model hydropower station; the rotational speed (n2) of the unit in the model hydropower station; the torque (M2) of the unit in the model hydropower station; and the flywheel torque of the unit in the model hydropower station. The turbine output P2 of the model hydroelectric power station;

[0088] 3.2) Set the relevant parameters of the test bench.

[0089] Determine the unit data of the model hydropower station on the test bench, including the nominal diameter D2 of the turbine, the head H2, the flow rate Q2, the rotational speed n2, the torque M2, and the flywheel torque. The turbine output P2 of the model hydroelectric power station;

[0090] Set the relevant parameters of the water diversion system of the model hydropower station in Computer 5, including the length L2 of each water diversion pipe in the model hydropower station, the diameter d2 of each water diversion pipe in the model hydropower station, the local head loss coefficient ξ2 at each point in the water diversion system of the model hydropower station, and the roughness n of each section of the pipe in the water diversion system of the model hydropower station. c2 The water hammer wave velocity a2 of each section of the water diversion system of the model hydropower station.

[0091] 3.3) Conduct transient process tests on a model hydropower station.

[0092] Based on the transient process time ratio of the model hydropower station x t The motion law of the guide vanes of the model hydropower station is calculated. By applying similar disturbances to the model hydropower station, the unit speed, spiral casing water pressure, tailrace water pressure and internal flow state change process of the model hydropower station are measured. The change process of relevant parameters of the prototype hydropower station is calculated in reverse according to formula (27).

[0093] Simulation verification:

[0094] To verify the effectiveness of the method of the present invention, a simulation calculation was performed using a hydropower station as an example. The water diversion system in the simulation was solved by the characteristic line method to solve the basic equation of water hammer, and the turbine was interpolated by the model comprehensive characteristic curve. In order to ensure that the hydraulic unit can meet the constraint of equation (27) during a large-scale transition process, the sudden 100% load shedding transition process of the unit was simulated.

[0095] Reference Figure 2This is a simplified schematic diagram of the prototype hydroelectric power station's on-site layout. Units #1 and #2 both have a rated speed of 214.3 r / min, a rated output of 266.7 MW, and a runner diameter of 4.36 m. Pipeline #1 is 550 m long, 15 m in diameter, has a roughness coefficient of 0.012, a local head loss coefficient at its inlet of 0.1, and a water hammer wave velocity of 1200 m / s. Pipeline #2 is 20 m long, 15 m in diameter, has a roughness coefficient of 0.012, a local head loss coefficient at its inlet of 0, and a water hammer wave velocity of 1200 m / s. Pipelines #3, #4, #5, and #6 have the same dimensions and parameters: all are 20 m long, 10 m in diameter, and have a roughness coefficient of 0.0. 12. The local head loss coefficient at the inlet of each pipeline is 0, and the water hammer wave velocity is 1200 m / s. Pipeline #7 is 20 m long, 15 m in diameter, and has a roughness of 0.012. The local head loss coefficient at the inlet of Pipeline #7 is 0, and the water hammer wave velocity is 1200 m / s. Pipeline #8 is 200 m long, 15 m in diameter, and has a roughness of 0.012. The local head loss coefficient at the inlet of Pipeline #8 is 0, and the water hammer wave velocity is 1200 m / s. The local head loss coefficient at the branch pipe from Pipeline #2 to Pipeline #3 and Pipeline #5 is 1. The local head loss coefficient at the converging pipe from Pipelines #4 and #6 to Pipeline #7 is 1.5. The rated head of the hydropower station is 202 m. The flywheel torque GD of Units #1 and #2 is... 2 Both are 2×10 5 t·m 2 After the load is shed, the guide vanes are closed in a 20-second interval, 100% of the time.

[0096] The turbine size ratio between the model hydropower station and the prototype hydropower station is selected as 1:10, the water diversion system size ratio is selected as 1:80, and the time ratio is selected as 1:0.5, i.e., x in formula (27) D =10, x L =80, x t =0.5. At this time, according to formula (27), we have: the rated speed of the generator unit of the model hydropower station is 857.2 r / min, the rated output is 1707 kW, the runner diameter is 0.436 m, the length of pipe #1 is 6.875 m, the diameter of pipe #1 is 0.1875 m, the roughness of pipe #1 is 0.0075, and the local head loss coefficient at the inlet of pipe #1 is 2.44 × 10 -5Pipeline #1 has a water hammer wave velocity of 7.5 m / s; Pipeline #2 has a length of 0.25 m, a diameter of 0.1875 m, a roughness of 0.0075, and a local head loss coefficient of 0 at its inlet; Pipelines #3, #4, #5, and #6 all have a length of 0.25 m, a diameter of 0.125 m, a roughness of 0.0075, and a local head loss coefficient of 0 at their inlets. The water hammer wave velocity in all pipelines is 7.5 m / s; Pipeline #7 is 0.25 m long, 0.1875 m in diameter, has a roughness of 0.0075, a local head loss coefficient at its inlet of 0, and a water hammer wave velocity of 7.5 m / s; Pipeline #8 is 2.5 m long, 0.1875 m in diameter, has a roughness of 0.0075, a local head loss coefficient at its inlet of 0, and a water hammer wave velocity of 7.5 m / s; the local head loss coefficient at the branch point from pipeline #2 to pipeline #3 and pipeline #5 is 2.44 × 10⁻⁶. -4 The local head loss coefficient at the confluence point where pipelines #4 and #6 converge into pipeline #7 is 3.66 × 10⁻⁶. -4 The rated head of the hydropower station is 32.32m, and the flywheel torque GD of Unit 1 and Unit 2 is... 2 Both are 16 t·m 2 After the load is shed, the guide vanes are closed in a 40-second interval, with each section closing 100%.

[0097] Both the model hydropower station's turbine units and the prototype hydropower station's turbine units underwent a 100% load shedding transition process. Based on equation (27), the turbine unit speed, turbine inlet pressure, turbine outlet pressure, and guide vane position of the model hydropower station were converted to those of the prototype hydropower station. The results were compared with the simulation results of the prototype hydropower station. Figure 3 .Depend on Figure 3 It is evident that the simulation data of the model hydropower station overlaps with that of the prototype hydropower station, indicating that the model hydropower station test can fully reflect the transition process corresponding to the prototype hydropower station.

[0098] Depend on Figure 3 It can be seen that the dynamic process of the model hydropower station can fully characterize the dynamic process of the prototype hydropower station, indicating that the semi-physical simulation model test method of the hydropower station transient process of the present invention can characterize the dynamic process of the prototype hydropower station through the test of the model hydropower station.

Claims

1. A semi-physical simulation model test method for the transient process of a hydropower station, characterized in that, Follow these steps: Step 1: Establish similarity criteria between the model hydropower station and the prototype hydropower station. The specific process is as follows: Since the model turbine and the prototype turbine have the same unit parameters when operating at similar conditions, therefore: ，（1） In equation (1), n 11 The unit speed of the water turbine, Q 11 The unit flow rate of the water turbine, M 11 The unit torque of the water turbine, n For the turbine speed, H For the turbine head, Q For the turbine flow rate, M For the turbine torque, D The nominal diameter of the turbine is given. Subscript 1 indicates parameters of the model turbine under similar operating conditions, and subscript 2 indicates parameters of the prototype turbine under similar operating conditions. The subscripts in the following expressions... 1,2 And so on. The following formula is obtained after transforming formula (1): ，（2） Assume the scale ratio between the model turbine and the prototype turbine is as follows: D 1: D 2=1: x D Then equation (2) can be transformed into: ，（3） For the water intake system, based on the rigid water hammer model of the pipeline, the following relationship exists in the water intake system: ，（4） In equation (4), h This represents the relative value of the turbine head deviation. q This is the relative value of the flow deviation. T w The inertial time constant of the water flow in the water diversion system, t For time; After another transformation, the expression for the inertial time constant of the water flow is obtained as follows: ，（5） In equation (5), L This refers to the length of the water supply pipe; A Let g be the cross-sectional area of ​​the water diversion pipeline, and g be the acceleration due to gravity. Since the model hydropower station and the prototype hydropower station operate under similar conditions, after combining equations (4) and (5), we have: ，（6） In equation (6), the subscript r This indicates the rated operating condition, and Δ represents the deviation from the initial operating condition. Dividing equation (6) by difference and then comparing the two equations, we have: ，（7） Since the operating conditions of the model hydropower station are similar to those of the prototype hydropower station, it is further transformed into: ，（8） Substituting equation (8) into equation (7), we get: ，（9） Assume the size ratio of the water diversion system model to the prototype is . L 1: L 2=1: x L The time scale of the system transition process is t 1: t 2=1: x t Then the transformed expression of equation (9) is: ，（10） Combining equations (3) and (10), we have: ，（11） For local head loss, we have: ，（12） In equation (12), ξ This is the local head loss coefficient, subscript J Indicates local head loss. Comparing and rearranging the two equations in equation (12), we get: ，（13） To maintain similar operating conditions between the prototype hydropower station and the model hydropower station during dynamic processes, the local head loss in the water diversion system should be consistent with the turbine head ratio. Combining equations (8), (11), and (13), we have: ，（14） Regarding the head loss along the pipeline, we have: ，（15） In equation (15), λ This is the coefficient for head loss along the friction path; d Diameter of the water supply pipe; subscript Y Indicates head loss along the route, Comparing the two equations in equation (15) and rearranging them, we get: ，（16） To maintain similar operating conditions between the prototype hydropower station and the model hydropower station during dynamic processes, the head loss along the water diversion system should be consistent with the turbine head ratio. Combining equations (8), (11), and (16), we have: ，（17） According to the Chezy-Manning formula, it can be transformed into the following equation: ，（18） In equation (18), n c For pipe roughness; R For the hydraulic radius of the pipeline, Comparing the two equations in equation (18) and rearranging them, we get: ，（19） During the dynamic process of a water turbine, the change in rotational speed must satisfy the following equation of motion: ，（20） In equation (20), GD 2 For the flywheel torque of the unit, Comparing the two equations in equation (20) and rearranging them, we get: ，（21） Combining equations (11) and (21), we have: ，（22） The output of the water turbine must satisfy the following expression: ，（23） Combining equations (11) and (23), we have: ，（24） The expression for water hammer-construction is: ，（25） In equation (25), a For water hammer wave speed, To ensure that the model hydropower station is similar to the prototype hydropower station during dynamic processes, the ratio of water hammer phase to time should be kept consistent. Therefore: ，（26） Thus, the similarity criterion between the model hydropower station and the prototype hydropower station is obtained, expressed as: ；（27） Step 2: Establish a semi-physical simulation test model of the hydropower station's transient process. The water diversion system was tested using real-time computer simulation; physical models were also used to obtain a more accurate understanding of the internal state of the turbine during the transient process. Step 3: Conduct a semi-physical simulation model test of the hydropower station's transient process and back-calculate the changes in relevant parameters of the prototype hydropower station.

2. The semi-physical simulation model test method for the transient process of a hydropower station according to claim 1, characterized in that, In step 2, the architecture of the semi-physical simulation test model of the hydropower station transition process includes a high-pressure tank (1), a pressure-generating tank 1 (3), a computer (5), a pressure-generating tank 2 (7), a vacuum tank (9), and a hydraulic turbine unit (13). The high-pressure tank (1) is filled with high-pressure air, and the pressure-generating tank 1 (3) contains some water and some air. The top of the pressure-generating tank 1 (3) is connected to both solenoid valve 1 (2) and solenoid valve 2 (4). The other end of solenoid valve 1 (2) is connected to the high-pressure tank (1), and the other end of solenoid valve 2 (4) is connected to the atmosphere or the vacuum tank (9). One end of the bottom of the pressure-generating tank 1 (3) is connected to the outlet of the water pump (11) through a pipe. A check valve 1 (10) is installed at the inlet of the water pump (11). The other end of the bottom of the pressure-generating tank 1 (3) is connected to the inlet of the spiral casing of the hydraulic turbine unit (13). The tailwater of the hydraulic turbine unit (13) is connected to the outlet of the water pump (11). The pipe end is connected to the bottom of the pressure tank 2 (7); the pressure tank 2 (7) is also filled with some water and some air. The bottom of the pressure tank 2 (7) is also equipped with a check valve 2 (15). The top of the pressure tank 2 (7) is connected to the solenoid valve 3 (6) and the solenoid valve 4 (8). The other end of the solenoid valve 3 (6) is connected to the atmosphere or the high pressure tank (1), and the other end of the solenoid valve 4 (8) is connected to the vacuum tank (9). The inlet end of the spiral casing of the hydraulic turbine (13) is equipped with a measuring device 1 (12), and the outlet end of the tailwater pipe of the hydraulic turbine (13) is equipped with a measuring device 2 (14). The measuring device 1 (12) and the measuring device 2 (14) are connected to the signal input end of the computer (5). The signal output end of the computer (5) is connected to the solenoid valve 1 (2), the solenoid valve 2 (4), the solenoid valve 3 (6), and the solenoid valve 4 (8).

3. The semi-physical simulation model test method for the transient process of a hydropower station according to claim 2, characterized in that, A mathematical model of the water diversion system is established in the computer (5). The mathematical model includes, but is not limited to, solving the pipeline water hammer mathematical model by the method of characteristics, or the method of wave characteristics, or the method of analytical function. The mathematical model includes all flow component models from the upstream reservoir to the turbine inlet and all flow component models from the turbine outlet to the downstream river channel. The turbine inlet and turbine outlet are the boundary conditions of the mathematical model. The real-time water pressure and flow rate at the turbine inlet are obtained by measuring device 1 (12), and the measured values ​​are transmitted to computer (5). Computer (5) uses the flow rate measured by measuring device 1 (12) as the boundary of the flow component model from the upstream reservoir to the turbine inlet, calculates the real-time water pressure at the turbine inlet, and compares it with the water pressure measured by measuring device 1 (12). When the water pressure measured by measuring device 1 (12) is lower than the calculated real-time water pressure, computer (5) controls solenoid valve 1 (2) to open and solenoid valve 2 (4) to close. At this time, the compressed air in the high pressure tank (1) enters the pressure tank (3), and the check valve (10) closes to prevent the water in the pressure tank (3) from being lost and to increase the water pressure at the turbine inlet. When the water pressure measured by the measuring device (12) is higher than the calculated real-time water pressure, the computer (5) controls the solenoid valve (2) to close and the solenoid valve (4) to open. At this time, the compressed air in the pressure tank (3) is discharged from the pressure tank, reducing the water pressure at the turbine inlet and thus ensuring that the water pressure at the turbine inlet is equal to the calculated water pressure by the computer (5) in real time. Meanwhile, the real-time water pressure and flow rate at the turbine outlet are obtained through measuring device two (14), and the measured values ​​are transmitted to computer (5). Computer (5) uses the flow rate measured by measuring device two (14) as the boundary of the flow component model from the turbine outlet to the downstream river channel, calculates the real-time water pressure at the turbine outlet, and compares it with the water pressure measured by measuring device two (14). When the water pressure measured by measuring device two (14) is lower than the calculated real-time water pressure, computer (5) controls solenoid valve three (6) to open and solenoid valve four (8) to close. At this time, the atmosphere enters the pressure tank 2 (7) through the solenoid valve 3 (6), increasing the water pressure at the turbine outlet. When the water pressure measured by the measuring device 2 (14) is higher than the calculated real-time water pressure, the computer (5) controls the solenoid valve 3 (6) to close and the solenoid valve 4 (8) to open. The air in the pressure tank 2 (7) enters the vacuum tank. At this time, the check valve 2 (15) closes to prevent the tail liquid from entering the pressure tank 2 and causing the pressure reduction to fail, thereby reducing the water pressure at the turbine outlet and ensuring that the water pressure at the turbine outlet is equal to the calculated water pressure by the computer (5) in real time.

4. The semi-physical simulation model test method for the transient process of a hydropower station according to claim 1, characterized in that, Step 3, the specific process is as follows: 3.1) Solve for the key parameters of the model hydropower station. Determine the turbine scale ratio between the prototype hydroelectric power station and the model hydroelectric power station. x D Water diversion system scale x L and the time scale of the transition process x t The lengths of each water diversion pipeline of the model hydropower station were calculated based on equation (27) and relevant parameters of the prototype hydropower station. L 2. Diameter of each water diversion pipe in the model hydroelectric power station d 2. Local head loss coefficients at various points in the water diversion system of the model hydropower station ξ 2. Roughness of each section of pipe in the water diversion system of the model hydropower station n c2 Water hammer wave velocity in each section of the water diversion system of the model hydropower station a 2. Nominal diameter of the turbine in the model hydroelectric power station D 2. Model hydroelectric power station head H 2. Flow rate of the model hydropower station unit Q 2. Rotation speed of the model hydropower station unit n 2. Torque of the model hydropower station unit M 2. The flywheel torque GD of the model hydropower station and the turbine output of the model hydropower station. P 2; 3.2) Set the relevant parameters of the test bench. Determine the unit data of the model hydropower station on the test bench, including the nominal diameter of the turbine of the model hydropower station. D 2. Head of the model hydroelectric power station H 2. Unit flow rate of the model hydropower station Q 2. Unit speed of the model hydroelectric power station n 2. Unit torque of the model hydroelectric power station M 2. The flywheel torque GD of the model hydropower station and the turbine output of the model hydropower station. P 2; Set the relevant parameters of the water diversion system of the model hydropower station in Computer 5, including the length of each water diversion pipe of the model hydropower station. L 2. Diameter of each water diversion pipe in the model hydroelectric power station d 2. Local head loss coefficients at various points in the water diversion system of the model hydropower station ξ 2. Roughness of each section of pipe in the water diversion system of the model hydropower station n c2 Water hammer wave velocity in each section of the water diversion system of the model hydropower station a 2; 3.3) Conduct transient process tests on a model hydroelectric power station. Based on the transition process time ratio of the model hydropower station x t The motion law of the guide vanes of the model hydropower station is calculated. By applying similar disturbances to the model hydropower station, the rotational speed of the unit, the water pressure of the spiral casing, the water pressure of the tailrace pipe and the flow state change process inside the turbine are measured. The change process of relevant parameters of the prototype hydropower station is calculated in reverse according to formula (27).

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