Method, device and medium for modeling and simulating transition process of complex water delivery and power generation system of one-hole multi-machine impulse hydropower station

Abstract

This invention discloses a method, device, and medium for modeling and simulating the transient process of an impulse hydropower station in a complex multi-machine, single-tunnel water conveyance power generation system, belonging to the field of hydropower station modeling and simulation technology. The method includes: establishing models of the turbine units and the water intake system in the complex multi-machine, single-tunnel water conveyance power generation system; performing Laplace transforms on the turbine unit and water intake system models to obtain the transfer functions of the turbine units and the water intake system; connecting the transfer functions of the turbine units and the water intake system into a control logic block diagram based on the signal flow direction and coupling relationship in the complex multi-machine, single-tunnel water conveyance power generation system; constructing a simulation model of the control logic block diagram; and performing dynamic simulation on the simulation model based on the initial operating boundary conditions of the complex multi-machine, single-tunnel water conveyance power generation system to obtain the simulation results. This invention significantly improves the computational efficiency of coupled simulation of multi-physics fields of water, machinery, and electricity while ensuring accuracy.

Description

Technical Field

[0001] This invention relates to the field of hydropower station modeling and simulation technology, and in particular to a method, device and medium for modeling and simulating the transient process of a complex water conveyance and power generation system with multiple turbines in a single tunnel. Background Technology

[0002] The complex multi-unit water conveyance and power generation system with a single tunnel is the core hub for energy conversion in a high-head impulse hydropower station, and the accuracy of its modeling determines the safety of the station's operation. On the one hand, the system consists of a long water diversion tunnel, a surge chamber, branch pipes, and multiple impulse turbine units. The pipeline topology is complex, and the significant elastic water hammer characteristics of pressurized pipelines have a decisive impact on the dynamic stability of the system. On the other hand, the multi-unit layout with a single tunnel leads to flow and pressure coupling between units through the branch pipes. Regulation disturbances from a single unit can be transmitted to neighboring units via water hammer waves, causing the system to exhibit high nonlinearity. Therefore, modeling this system is essentially a complex coordinated control problem involving multivariable interactions and multi-physics coupling.

[0003] Currently, research on impulse hydropower stations largely focuses on hydraulic calculations and unit control strategies based on the method of characteristics. However, existing technologies face significant challenges in constructing coupled models of the entire water-machine-electric system: First, hydraulic partial differential equations and electrical ordinary differential equations exhibit mathematical heterogeneity; the former requires spatiotemporal grid discretization, which is difficult to directly match with the latter's continuous integration mechanism based on time steps. Second, while some scholars have attempted to simplify hydraulic models, they often employ rigid assumptions for long water diversion pipelines, leading to model distortion and making it difficult to reflect real hydraulic disturbance mechanisms. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method, device and medium for modeling and simulating the transient process of a complex water conveyance and power generation system with multiple turbines in a single tunnel. This method can retain the accuracy of elastic water hammer calculation while achieving seamless coupling with the electrical control system within the same mathematical framework, thereby significantly improving the computational efficiency of the coupled simulation of the water, machinery and electrical multi-physics fields while ensuring accuracy.

[0005] To achieve the above objectives, the present invention is implemented using the following technical solution:

[0006] On the one hand, this invention provides a method for modeling and simulating the transient process of a complex multi-machine water conveyance and power generation system in an impulse hydropower station, including:

[0007] Establish models of the turbine units and water diversion system in a complex water conveyance and power generation system with multiple turbines in a single tunnel;

[0008] The transfer functions of the turbine unit and the water diversion system are obtained by performing a Laplace transform on the turbine unit model and the water diversion system model.

[0009] Based on the signal flow direction and coupling relationship in a complex water conveyance and power generation system with multiple turbines in one tunnel, the transfer functions of the turbine units and the water diversion system are connected and drawn into a control logic block diagram.

[0010] A simulation model of the control logic block diagram was constructed. Based on the initial operating boundary conditions of the complex water conveyance and power generation system with multiple machines in one tunnel, dynamic simulation was performed on the simulation model to obtain the simulation results.

[0011] Optionally, the turbine unit model includes turbine equations, generator equations, and governor equations;

[0012] The water diversion system model includes the dynamic equations for the water diversion tunnel, the continuity equation for the surge tank, and the dynamic equations for the pressure pipeline. The dynamic equations for the pressure pipeline are constructed based on the pipeline layout of the water diversion system, including dynamic equations for pressure pipelines containing only primary branch pipes and dynamic equations for pressure pipelines containing secondary branch pipes.

[0013] The dynamic equations for the pressure pipeline containing only a single-stage branch pipe include the dynamic equations for the main pressure pipeline, the flow continuity equation at the bifurcation point, and the dynamic equations for each branch pipe connected to the main pressure pipeline.

[0014] The dynamic equations for the pressure pipeline containing secondary bifurcation pipes include the flow continuity equation at the primary bifurcation point, the dynamic equations for the secondary pressure pipeline, the flow continuity equation at the secondary bifurcation point, and the dynamic equations for each bifurcation pipe connected to the secondary pressure pipeline.

[0015] Optionally, the turbine equations are expressed as:

[0016] ;

[0017] The generator equation is expressed as:

[0018] ;

[0019] The governor equation is expressed as follows:

[0020] ;

[0021] in, Indicates relative dynamic torque; Indicates the relative flow rate of the branch pipe; , , These represent the relative opening of the turbine guide vanes. Turbine working head Relative deviation of turbine speed The corresponding turbine torque transmission coefficient; , , These represent the relative opening of the turbine guide vanes. Turbine working head Relative deviation of turbine speed The corresponding turbine flow transfer coefficient; This represents the inertial time constant of the water turbine; This indicates the load disturbance of the generator in the water turbine; This represents the self-regulating coefficient of the generator in the water turbine; , These represent the proportional gain and integral gain of the water turbine, respectively.

[0022] Optionally, the dynamic equation of the water diversion tunnel is expressed as:

[0023] ;

[0024] The continuity equation for the pressure regulating chamber is expressed as:

[0025] ;

[0026] in, Indicates the relative flow rate of the water diversion tunnel The derivative; Represent the dynamic equation; This indicates the relative deviation of the turbine's rotational speed; This indicates the relative water level fluctuation in the surge tank; Indicates the dynamic coefficient of the water diversion tunnel; This represents the damping and inertia coefficient of the water diversion tunnel; Represents the boundary constraint function of the water diversion tunnel; This indicates the relative flow rate at the bifurcation point; This indicates the relative flow rate at the first-order bifurcation point; This represents the time constant of the pressure regulating chamber.

[0027] Optionally, the dynamic equation for the main pressure pipeline is expressed as:

[0028] ;

[0029] The continuity equation for the flow at the bifurcation point is expressed as:

[0030] ;

[0031] The dynamic equations for each branch pipe connected to the main pressure pipeline are expressed as follows:

[0032] ;

[0033] in, Represents the relative flow rate at the bifurcation point. The derivative; Represent the dynamic equation; This indicates the relative deviation of the turbine's rotational speed; This indicates the relative water level fluctuation in the surge tank; Indicates the dynamic coefficient of the main pressure pipeline; This represents the damping and inertia coefficient of the main pressure pipeline; Represents the boundary constraint function for the main pressure pipeline; , These represent the relative speed deviations of the turbine relative to the turbine's operating head and the bifurcation pipe relative to the turbine's operating head, respectively. This indicates a branch pipe connected to the main pressure pipeline. Flow allocation coefficient; This indicates a branch pipe connected to the main pressure pipeline. relative flow The derivative; Indicates the number of branch pipes connected to the main pressure pipeline; , , These represent the branch pipes connected to the main pressure pipeline. Dynamic coefficients, damping and inertia coefficients, and boundary constraint functions.

[0034] Optionally, the flow continuity equation at the first-order bifurcation point is expressed as:

[0035] ;

[0036] The dynamic equation for the secondary pressure pipeline is expressed as:

[0037] ;

[0038] ;

[0039] The continuity equation for the flow at the second-order bifurcation point is expressed as:

[0040] ;

[0041] ;

[0042] The dynamic equations for each branch pipe connected to the secondary pressure pipeline are expressed as follows:

[0043] ;

[0044] in, This indicates the relative flow rate at the first-order bifurcation point; This represents the relative flow rate at bifurcation point 1 (second-order bifurcation point). The derivative; This indicates the relative flow rate at the second-order bifurcation point 2. The derivative; , These represent the flow distribution coefficients at second-order bifurcation point 1 and second-order bifurcation point 2, respectively; Represent the dynamic equation; This indicates the relative deviation of the turbine's rotational speed; This indicates the relative water level fluctuation in the surge tank; , , These represent the dynamic coefficients, damping and inertia coefficients, and boundary constraint functions of the secondary pressure pipe 1, respectively. , These represent the relative speed deviations of the turbine relative to the turbine's operating head and the bifurcation pipe relative to the turbine's operating head, respectively. , , These represent the dynamic coefficients, damping and inertia coefficients, and boundary constraint functions of the secondary pressure pipe 2, respectively. This indicates the branch pipe connected to the secondary pressure pipeline 1. Flow allocation coefficient; This indicates the branch pipe connected to the secondary pressure pipeline 1. The relative flow rate; Indicates the number of branch pipes connected to secondary pressure pipe 1; This indicates the branch pipe connected to the secondary pressure pipe 2. Flow allocation coefficient; This indicates the branch pipe connected to the secondary pressure pipe 2. The relative flow rate; Indicates the number of branch pipes connected to secondary pressure pipe 2; This indicates the branch pipe connected to the secondary pressure pipeline 1. relative flow The derivative; , , These represent the branch pipes connected to the secondary pressure pipeline 1. Dynamic coefficients, damping and inertia coefficients, boundary constraint functions; This indicates the branch pipe connected to the secondary pressure pipe 2. relative flow The derivative; , , These represent the branch pipes connected to the secondary pressure pipeline 2. Dynamic coefficients, damping and inertia coefficients, and boundary constraint functions.

[0045] Optionally, the drawing of the control logic block diagram includes:

[0046] The governor's opening signal or on-site measured data, as well as the generator's unit speed signal, are connected to the turbine's input terminal. The turbine outputs the unit flow signal and the turbine torque signal.

[0047] The turbine's output flow rate signal is connected to the input of the water intake system. The water intake system outputs the turbine's working head signal and feeds it back to the turbine's input.

[0048] The turbine torque signal is connected to the generator input terminal. The generator outputs the unit speed signal and feeds it back to the turbine input terminal and the governor input terminal. The governor outputs the opening signal to the turbine based on the deviation between the unit speed signal and the set value, thus completing the drawing of the control logic block diagram.

[0049] Optionally, based on the initial operating boundary conditions of the complex hydropower generation system with multiple generators in one tunnel, dynamic simulation is performed on the simulation model to obtain simulation results, including:

[0050] If on-site measured data exists, the governor in the simulation model is disconnected, and the on-site measured turbine deflector opening data and nozzle opening data are used as inputs to the turbine. Dynamic simulation is then performed on the simulation model to obtain the simulation results.

[0051] If no on-site measured data is available, the speed governor in the simulation model is connected. The speed governor outputs an opening signal to the turbine through the frequency step disturbance or power set disturbance at the input terminal, and performs dynamic simulation on the simulation model to obtain the simulation results.

[0052] Secondly, the present invention provides a modeling and simulation device for the transient process of a complex multi-machine water conveyance and power generation system in a single-tunnel, impulse hydropower station, comprising:

[0053] The model building module is used to: build models of the turbine units and the water diversion system in a complex water conveyance and power generation system with multiple turbines in a single tunnel;

[0054] The model transformation module is used to perform Laplace transform on the turbine generator model and the water diversion system model to obtain the transfer function of the turbine generator and the transfer function of the water diversion system.

[0055] The block diagram drawing module is used to: connect the transfer functions of the turbine units and the transfer functions of the water diversion system into a control logic block diagram based on the signal flow direction and coupling relationship in a complex water conveyance and power generation system with multiple turbines in one tunnel;

[0056] The model simulation module is used to: build a simulation model of the control logic block diagram, perform dynamic simulation on the simulation model based on the initial operating boundary conditions of the complex water conveyance and power generation system with multiple machines in one tunnel, and obtain simulation results.

[0057] Thirdly, the present invention provides a computer-readable storage medium storing a computer program / instruction thereon, which, when executed by a processor, implements the steps of the method for modeling and simulating the transient process of a complex water conveyance and power generation system with multiple turbines in a single tunnel as described in the first aspect.

[0058] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0059] This invention describes the partial differential equations of elastic water hammer in hydraulic systems and transforms them into algebraic equations through Laplace transform. These equations are then coupled with the ordinary differential equations of electromechanical control systems within the same mathematical framework. This overcomes the numerical computation heterogeneity and boundary interaction difficulties encountered in the traditional method of characteristics and joint simulation of electrical systems. It can retain the calculation accuracy of elastic water hammer while achieving seamless coupling with the electrical control system within the same mathematical framework. This significantly improves the computational efficiency of coupled simulation of multi-physics fields of water, electromechanical, and electrical systems while ensuring accuracy. It provides standardized model support for the control strategy design and stability analysis of impulse hydropower stations. Attached Figure Description

[0060] Figure 1 The diagram shown is a flowchart of the transient process modeling and simulation method for a complex water conveyance and power generation system with multiple turbines in one tunnel, according to one embodiment of the present invention.

[0061] Figure 2 The diagram shown is a structural schematic of a complex water conveyance and power generation system consisting of a single tunnel and three turbines, with only a single-stage branch pipe, in one embodiment of the present invention.

[0062] Figure 3 The diagram shown is a structural schematic of a complex water conveyance and power generation system with a secondary branch pipe and four turbines in one tunnel, according to one embodiment of the present invention.

[0063] Figure 4 The diagram shown is a schematic diagram of the control logic in one embodiment of the present invention. Detailed Implementation

[0064] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments of the present invention and the specific features in the embodiments are detailed descriptions of the technical solution of the present invention, rather than limitations thereof. In the absence of conflict, the embodiments of the present invention and the technical features in the embodiments can be combined with each other.

[0065] The term "and / or" simply describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. Additionally, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0066] Example 1

[0067] This embodiment introduces a modeling and simulation method for the transient process of an impulse hydropower station in a complex multi-machine water conveyance and power generation system with one tunnel, such as... Figure 2 The diagram shows a complex water conveyance and power generation system consisting of a single tunnel and three turbines, with only a primary branch pipe. This system includes an upstream reservoir, a water diversion tunnel, an upstream surge chamber, a primary branch pipe, branch pipe 1, branch pipe 2, branch pipe 3, turbine 1, turbine 2, turbine 3, generator 1, generator 2, and generator 3. Generator 1 is installed on turbine 1, generator 2 on turbine 2, and generator 3 on turbine 3. The water diversion tunnel is located between the upstream reservoir and the upstream surge chamber and supplies water to multiple turbine units. The primary branch pipe downstream of the surge chamber connects to turbine 1 via branch pipe 1, turbine 2 via branch pipe 2, and turbine 3 via branch pipe 3, forming a complex water conveyance and power generation system consisting of a single tunnel and three turbines, forming a complex water conveyance and power generation system consisting of a single tunnel and three turbines, with only a primary branch pipe.

[0068] Figure 3 The diagram shows a complex water conveyance and power generation system (one tunnel, four turbines) for an impulse hydroelectric power station, including an upstream reservoir, a water diversion tunnel, an upstream surge chamber, a primary branch pipe, secondary pressure pipeline 1, secondary pressure pipeline 2, branch pipe 1, branch pipe 2, branch pipe 3, branch pipe 4, turbine 1, turbine 2, turbine 3, turbine 4, generator 1, generator 2, generator 3, and generator 4. Generator 1 is installed on turbine 1, generator 2 is installed on turbine 2, and generator 3 is installed on turbine 3. The No. 4 generator is installed on the No. 4 turbine. The water diversion tunnel is located between the upstream reservoir and the upstream surge chamber, and is used to supply water to multiple turbine units. The primary branch pipe downstream of the surge chamber is connected to the secondary branch pipe 1 through the secondary pressure pipe 1, and to the secondary branch pipe 2 through the secondary pressure pipe 2. The secondary branch pipe 1 is connected to the No. 1 turbine through the branch pipe 1, and to the No. 2 turbine through the branch pipe 2. The secondary branch pipe 2 is connected to the No. 3 turbine through the branch pipe 3, and to the No. 4 turbine through the branch pipe 4, forming a complex water conveyance and power generation system with one tunnel and four turbines, forming an impulse hydropower station.

[0069] The method includes the following steps:

[0070] Step 1: Constructing the differential equation model of the entire system, specifically as follows:

[0071] Establish models of the turbine units and water diversion system in a complex water conveyance and power generation system with multiple turbines in one tunnel.

[0072] Regardless of the layout of a complex water conveyance and power generation system with multiple turbines in a single tunnel, a unified turbine unit model is established, which includes turbine equations, generator equations, and governor equations.

[0073] The water diversion system model includes the dynamic equations for the water diversion tunnel, the continuity equation for the surge tank, and the dynamic equations for the pressure pipeline. The dynamic equations for the pressure pipeline are constructed based on the pipeline layout of the water diversion system, including dynamic equations for pressure pipelines with only a first-stage branch and dynamic equations for pressure pipelines with a second-stage branch.

[0074] If the pipeline layout of the water diversion system is a layout with only one branch pipe, that is, the water flows through the main pressure pipeline and is directly distributed to each branch pipe by the first branch pipe, then the dynamic equation of the pressure pipeline with only one branch pipe includes the dynamic equation of the main pressure pipeline, the flow continuity equation at the bifurcation point, and the dynamic equation of each branch pipe connected to the main pressure pipeline.

[0075] If the pipeline layout of the water diversion system is a layout with two-stage branch pipes, that is, after the water flows through the water diversion tunnel, it is distributed to the secondary pressure pipeline by the primary branch pipe, and then distributed to each branch pipe by the secondary branch pipe. The dynamic equation of the pressure pipeline with two-stage branch pipes includes the flow continuity equation at the primary branch point, the dynamic equation of the secondary pressure pipeline, the flow continuity equation at the secondary branch point, and the dynamic equation of each branch pipe connected to the secondary pressure pipeline.

[0076] The dynamic equation for a water diversion tunnel considering elastic water hammer is expressed as follows:

[0077] .

[0078] The continuity equation for the pressure regulating chamber is expressed as:

[0079] .

[0080] in, Indicates the relative flow rate of the water diversion tunnel The derivative of , This indicates the current flow rate of the water diversion tunnel; This indicates the initial flow rate of the water diversion tunnel; Represent the dynamic equation; This indicates the relative deviation of the turbine's rotational speed. This indicates the current rotational speed of the water turbine; This indicates the initial speed of the water turbine; all water turbines have the same initial speed. This indicates the relative water level fluctuation in the surge tank. Indicates the initial water level in the surge tank; Indicates the current water level in the surge tank; This indicates the initial value of the turbine's operating head; This represents the dynamic coefficient of the water diversion tunnel, the value of which depends on the water hammer wave velocity and geometric dimensions of the water diversion tunnel. This represents the damping and inertia coefficient of the water diversion tunnel, the value of which depends on the inertial time constant of the water flow and the water hammer phase length of the water diversion tunnel; The boundary constraint function of the water diversion tunnel represents the effect of the surge tank water level and the friction resistance along the pipeline on the flow rate change; This indicates the relative flow rate at the bifurcation point; This indicates the relative flow rate at the first-order bifurcation point; Represents the time constant of the surge tank; water hammer phase of the water diversion tunnel. , Indicates the length of the water diversion tunnel. This indicates the water hammer wave velocity in the water diversion tunnel. This represents the inertial time constant of the water flow in the water diversion tunnel.

[0081] Dynamic equations for pressure pipelines containing only a single-stage branch pipe:

[0082] Using the same method as for the water diversion tunnel, the equations for the main pressure pipeline are established. However, unlike the water diversion tunnel, the pressure boundary conditions of the main pressure pipeline change: its inlet is constrained by the water level in the upstream surge chamber, and its outlet is constrained by the dynamic water pressure at the bifurcation point. The dynamic equation for the main pressure pipeline, considering elastic water hammer, is expressed as follows:

[0083] .

[0084] The continuity equation for the flow at the bifurcation point is expressed as:

[0085] .

[0086] For each branch pipe connecting to the turbine unit, based on the established dynamic equations, the boundary conditions of the branch pipe are: the head end is constrained by the dynamic water pressure at the bifurcation point, and the tail end is constrained by the turbine's working head. Considering elastic water hammer, the dynamic equations of each branch pipe connected to the main pressure pipeline are expressed as follows:

[0087] .

[0088] in, Represents the relative flow rate at the bifurcation point. The derivative; Represent the dynamic equation; This indicates the relative deviation of the turbine's rotational speed; This indicates the relative water level fluctuation in the surge tank; This represents the dynamic coefficient of the main pressure pipeline, the value of which depends on the water hammer wave velocity and geometry of the main pressure pipeline. This represents the damping and inertia coefficient of the main pressure pipeline, the value of which depends on the water flow inertia time constant and water hammer phase length of the main pressure pipeline; The boundary constraint function of the main pressure pipeline represents the effect of the pressure chamber water level, the friction resistance along the pipeline, and the head of the branch pipe on the flow rate change. , These represent the relative speed deviations of the turbine relative to the turbine's operating head and the bifurcation pipe relative to the turbine's operating head, respectively. This indicates a branch pipe connected to the main pressure pipeline. Flow allocation coefficient , This indicates a branch pipe connected to the main pressure pipeline. Initial traffic; This indicates the initial flow rate of the branch pipe 1 connected to the main pressure pipeline; This indicates a branch pipe connected to the main pressure pipeline. relative flow The derivative of , This indicates a branch pipe connected to the main pressure pipeline. Current traffic; This indicates a branch pipe connected to the main pressure pipeline. Initial traffic; Indicates the number of branch pipes connected to the main pressure pipeline; , , These represent the branch pipes connected to the main pressure pipeline. Dynamic coefficients, damping and inertia coefficients, boundary constraint functions; Its value depends on the water hammer wave velocity and geometry of the bifurcation pipe. Its value depends on the inertial time constant of the water flow in the bifurcation pipe and the water hammer phase length. This indicates the effect of pipeline friction resistance, branch pipe head, and turbine head on flow rate changes.

[0089] Dynamic equations for pressure pipelines with secondary branch pipes:

[0090] The continuity equation for the flow at the first-order bifurcation point is expressed as:

[0091] .

[0092] Using the same method as for the water diversion tunnel, the equations for the secondary pressure pipeline are established. However, unlike the water diversion tunnel, the pressure boundary conditions for the secondary pressure pipeline change: its initial end is constrained by the water level in the upstream surge chamber, and its final end is constrained by the dynamic water pressure at the secondary bifurcation point. The dynamic equation for the secondary pressure pipeline, considering elastic water hammer, is expressed as follows:

[0093] ;

[0094] .

[0095] The continuity equation for the flow at the second-order bifurcation point is expressed as:

[0096] ;

[0097] .

[0098] For each branch pipe connecting to the turbine unit, the dynamic equations are established in the same way. The boundary conditions for the branch pipes are: the head end is constrained by the dynamic water pressure at the secondary bifurcation point, and the tail end is constrained by the turbine's working head. Considering elastic water hammer, the dynamic equations for each branch pipe connected to the secondary pressure pipeline are expressed as follows:

[0099] .

[0100] in, This indicates the relative flow rate at the first-order bifurcation point; This represents the relative flow rate at bifurcation point 1 (second-order bifurcation point). The derivative; This indicates the relative flow rate at the second-order bifurcation point 2. The derivative; , These represent the flow distribution coefficients at second-order bifurcation point 1 and second-order bifurcation point 2, respectively; Represent the dynamic equation; This indicates the relative deviation of the turbine's rotational speed; This indicates the relative water level fluctuation in the surge tank; , , These represent the dynamic coefficients, damping and inertia coefficients, and boundary constraint functions of the secondary pressure pipe 1, respectively. , These represent the relative speed deviations of the turbine relative to the turbine's operating head and the bifurcation pipe relative to the turbine's operating head, respectively. , , These represent the dynamic coefficients, damping and inertia coefficients, and boundary constraint functions of the secondary pressure pipe 2, respectively. This indicates the branch pipe connected to the secondary pressure pipeline 1. Flow allocation coefficient; This indicates the branch pipe connected to the secondary pressure pipeline 1. The relative flow rate; Indicates the number of branch pipes connected to secondary pressure pipe 1; This indicates the branch pipe connected to the secondary pressure pipe 2. Flow allocation coefficient; This indicates the branch pipe connected to the secondary pressure pipe 2. The relative flow rate; Indicates the number of branch pipes connected to secondary pressure pipe 2; This indicates the branch pipe connected to the secondary pressure pipeline 1. relative flow The derivative; , , These represent the branch pipes connected to the secondary pressure pipeline 1. Dynamic coefficients, damping and inertia coefficients, boundary constraint functions; This indicates the branch pipe connected to the secondary pressure pipe 2. relative flow The derivative; , , These represent the branch pipes connected to the secondary pressure pipeline 2. Dynamic coefficients, damping and inertia coefficients, and boundary constraint functions.

[0101] The turbine equation is expressed as:

[0102] ;

[0103] The generator equation is expressed as:

[0104] ;

[0105] The governor equation is expressed as:

[0106] ;

[0107] in, Indicates relative dynamic torque; Indicates the relative flow rate of the branch pipe; , , These represent the relative opening of the turbine guide vanes. Turbine working head Relative deviation of turbine speed The corresponding turbine torque transmission coefficient; , , These represent the relative opening of the turbine guide vanes. Turbine working head Relative deviation of turbine speed The corresponding turbine flow transfer coefficient, Indicates the flow rate of the branch pipe; This represents the inertial time constant of the water turbine; This indicates the load disturbance of the generator in the water turbine; This represents the self-regulating coefficient of the generator in the water turbine; , These represent the proportional gain and integral gain of the water turbine, respectively. , This indicates the current guide vane opening of the water turbine; This indicates the initial guide vane opening of the turbine; all turbines have the same initial guide vane opening.

[0108] Step 2: Derive the transfer function using the Laplace transform, specifically as follows:

[0109] The transfer functions of the turbine unit and the water diversion system are obtained by performing Laplace transform on the turbine unit model and the water diversion system model.

[0110] The transfer function of a hydro turbine unit includes the turbine transfer function, the generator transfer function, and the governor transfer function.

[0111] The transfer functions of the water diversion system include the power transfer function of the water diversion tunnel, the continuity transfer function of the surge tank, and the power transfer function of the pressure pipeline.

[0112] The power transfer function for pressure pipelines includes the power transfer function for pressure pipelines with only a single-stage branch and the power transfer function for pressure pipelines with a second-stage branch:

[0113] The power transmission function of a pressure pipeline containing only a single-level branch pipe includes the power transmission function of the main pressure pipeline, the flow continuity transmission function at the branch point, and the power transmission function of each branch pipe.

[0114] The dynamic equations for a pressure pipeline with secondary bifurcation include the flow continuity transfer function at the primary bifurcation point, the dynamic transfer function of the secondary pressure pipeline, the flow continuity transfer function at the secondary bifurcation point, and the dynamic transfer function of each bifurcation pipe.

[0115] Each transfer function is obtained by transforming each equation through Laplace transform and Taylor series expansion.

[0116] Step 3: Draw the system coupling control logic block diagram, specifically:

[0117] like Figure 4 As shown, a hydraulic and mechanical coupling loop is constructed to establish the interaction between the water intake system and the mechanical characteristics of the turbine unit. Specifically, the turbine's output flow rate signal is connected to the input end of the water intake system (including the water intake tunnel, surge chamber, pressure pipeline, and branch pipe). The water flow in the pipeline will generate head loss and elastic water hammer effect. The water intake system outputs the turbine's operating head signal at the current moment, and finally feeds the turbine's operating head signal back to the turbine's input end, thus forming a hydraulic and mechanical closed-loop coupling loop that reflects the mutual constraint between flow rate and head.

[0118] The energy conversion logic of the unit is constructed to simulate the process of the turbine converting water energy into mechanical energy. The input interface of the turbine is configured so that, in addition to receiving the turbine working head signal, it also needs to receive the field measured data or the opening signal output by the governor, as well as the unit speed signal from the generator. Based on the above inputs, the turbine performs calculations based on the turbine flow equation. On the one hand, it outputs the unit flow signal to the water intake system to maintain hydraulic balance, and on the other hand, it outputs the turbine torque signal to the generator.

[0119] The mechanical, electrical, and regulating loops are constructed. The turbine torque signal output from the turbine is connected to the generator input. The generator calculates the unit speed signal and sends it as feedback to two targets: one is the turbine input, and the other is the governor input. The governor calculates the deviation between the received unit speed signal and the set value using PID control and outputs the corrected opening signal to the turbine, thus completing the drawing of the physical model closed-loop control block diagram.

[0120] Step 4: Build the simulation model, specifically:

[0121] A simulation model of the control logic block diagram is built. The simulation model can be a Simulink model. Based on the closed-loop control logic block diagram of a complex hydropower station with multiple turbines in a single tunnel, the subsystem modules are built and connected, and the physical parameters of the system are configured. This requires parameter calculation and configuration based on the actual design data provided by the power station. The specific logic is as follows:

[0122] Based on the hydraulic layout drawings and specifications, the geometric dimensions of the water diversion tunnel, pressure pipeline, and various levels of branch pipes are extracted. Based on these dimensions, parameters such as the flow inertia time constant and elastic water hammer phase length of each pipe section are calculated. The static head is determined based on the difference between the upper reservoir water level and the unit installation elevation. Combined with the actual operating head under the unit's response conditions, the head loss of the water diversion system is calculated using the difference between the two. Using the turbine model's comprehensive characteristic curve, the steady-state operating point of the unit on the characteristic curve is determined based on the initial conditions, and the six transfer coefficients corresponding to this operating point are calculated. Finally, the calculated physical parameters and state variables are assigned to various modules in the simulation model to achieve parameter configuration of the simulation model.

[0123] Step 5: Execute the simulation and output the response, specifically:

[0124] To ensure consistency between the simulation and the actual physical process, while also considering the ability to predict unknown operating conditions, if on-site measured data from the power plant is available, the measured opening signal should be used as input, since it is derived from the governor output of the actual power plant. In this case, the governor should not be connected to the simulation model. If on-site measured data from the power plant is unavailable, the governor should be connected to the simulation model, and the corresponding opening signal should be used as the turbine input. The specific implementation is as follows:

[0125] Determine whether on-site measured data from the power plant is available;

[0126] If on-site measured data exists, given that on-site data has the highest reliability in reflecting the real response, the simulation uses the measured data as input. In this case, the governor in the simulation model is disconnected, and the on-site measured turbine deflector opening data and nozzle opening data are used as the turbine input. Dynamic simulation is then performed on the simulation model to obtain the simulation results, thereby eliminating the influence of parameter deviations between the governor and the actual governor and realizing the reproduction of the power plant's operating conditions.

[0127] If no on-site measured data is available, the speed governor in the simulation model is connected. The speed governor outputs the opening signal to the turbine through the frequency step disturbance or power command disturbance set at the input terminal, and performs dynamic simulation on the simulation model to obtain the simulation results. This effectively makes up for the deficiency of not being able to obtain dynamic response when there is a lack of measured data or when it is difficult to conduct real machine tests, and realizes the simulation of various working conditions.

[0128] The simulation model's operating conditions mainly include typical conditions such as load shedding, primary frequency regulation, and load adjustment. The simulation results mainly include dynamic responses such as water distribution loop pressure, unit active power output, and frequency, thereby enabling dynamic characteristic analysis of the system.

[0129] This embodiment sets up both open-loop and closed-loop input interfaces in the simulation model, which can drive the model using the measured nozzle opening data and deflector opening data, as well as preset frequency or power disturbances. Since this method can both reproduce the actual working conditions using measured data to verify the model parameters, and predict the system response under extreme working conditions where there is no measured data or it is difficult to measure, the simulation platform has the dual functions of model verification and predictive analysis, providing a flexible and intuitive engineering tool for the grid connection test analysis, fault review and operation parameter tuning of hydropower stations.

[0130] The active power output curve of the unit, the pressure curve of the turbine distribution ring pipe, and the frequency curve of the unit output by the simulation model under the corresponding operating conditions are compared with the measured data collected in the field test of the hydropower station.

[0131] The accuracy of the simulation model was verified by combining qualitative analysis and quantitative calculation.

[0132] First, a qualitative analysis of trend comparison is conducted. The dynamic response curve obtained from the simulation is compared with the actual measured curve in the field under the same coordinate system. The focus is on observing whether the waveform trend, phase change and key inflection points of the two are consistent during the transition process, so as to qualitatively determine whether the simulation model correctly reflects the dynamic characteristics of the system.

[0133] Secondly, quantitative analysis of numerical comparison is carried out. Based on the measured data, the maximum relative error of the simulation data relative to the measured data is calculated and a specific numerical comparison is performed.

[0134] Finally, the evaluation conclusion is as follows: if the measured curve and the simulation curve are highly consistent in terms of their changing trends, it can be verified that the simulation model of the complex water conveyance and power generation system with multiple turbines in one tunnel has high accuracy, providing ideas for the subsequent optimization of control strategies and hydraulic disturbance analysis of actual power plants.

[0135] Example 2

[0136] Based on Example 1, this example introduces a modeling and simulation device for the transient process of a complex water conveyance and power generation system with multiple turbines in a single tunnel, including:

[0137] The model building module is used to: build models of the turbine units and the water diversion system in a complex water conveyance and power generation system with multiple turbines in a single tunnel;

[0138] The model transformation module is used to perform Laplace transform on the turbine generator model and the water diversion system model to obtain the transfer function of the turbine generator and the transfer function of the water diversion system.

[0139] The block diagram drawing module is used to: connect the transfer functions of the turbine units and the transfer functions of the water diversion system into a control logic block diagram based on the signal flow direction and coupling relationship in a complex water conveyance and power generation system with multiple turbines in one tunnel;

[0140] The model simulation module is used to: build a simulation model of the control logic block diagram, perform dynamic simulation on the simulation model based on the initial operating boundary conditions of the complex water conveyance and power generation system with multiple machines in one tunnel, and obtain simulation results.

[0141] The specific functions of each module described above are explained in the relevant content of the method in Embodiment 1, and will not be repeated here.

[0142] Example 3

[0143] This embodiment introduces a computer-readable storage medium storing a computer program / instruction. When the computer program / instruction is executed by a processor, it implements the steps of the transient process modeling and simulation method for a complex water conveyance and power generation system with multiple turbines in a single tunnel as described in Embodiment 1.

[0144] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0145] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0146] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0147] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0148] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A method for modeling and simulating the transient process of a complex multi-machine water conveyance and power generation system in an impulse hydropower station, characterized in that, include: Establish models of the turbine units and water diversion system in a complex water conveyance and power generation system with multiple turbines in a single tunnel; The transfer functions of the turbine unit and the water diversion system are obtained by performing a Laplace transform on the turbine unit model and the water diversion system model. Based on the signal flow direction and coupling relationship in a complex water conveyance and power generation system with multiple turbines in one tunnel, the transfer functions of the turbine units and the water diversion system are connected and drawn into a control logic block diagram. A simulation model of the control logic block diagram was constructed. Based on the initial operating boundary conditions of the complex water conveyance and power generation system with multiple machines in one tunnel, dynamic simulation was performed on the simulation model to obtain the simulation results.

2. The method for modeling and simulating the transient process of a complex water conveyance and power generation system with multiple turbines in a single tunnel, as described in claim 1, is characterized in that... The turbine unit model includes turbine equations, generator equations, and governor equations; The water diversion system model includes the dynamic equations for the water diversion tunnel, the continuity equation for the surge tank, and the dynamic equations for the pressure pipeline. The dynamic equations for the pressure pipeline are constructed based on the pipeline layout of the water diversion system, including dynamic equations for pressure pipelines containing only primary branch pipes and dynamic equations for pressure pipelines containing secondary branch pipes. The dynamic equations for the pressure pipeline containing only a single-stage branch pipe include the dynamic equations for the main pressure pipeline, the flow continuity equation at the bifurcation point, and the dynamic equations for each branch pipe connected to the main pressure pipeline. The dynamic equations for the pressure pipeline containing secondary bifurcation pipes include the flow continuity equation at the primary bifurcation point, the dynamic equations for the secondary pressure pipeline, the flow continuity equation at the secondary bifurcation point, and the dynamic equations for each bifurcation pipe connected to the secondary pressure pipeline.

3. The method for modeling and simulating the transient process of a complex water conveyance and power generation system with multiple turbines in a single tunnel, as described in claim 2, is characterized in that... The turbine equation is expressed as follows: ； The generator equation is expressed as: ； The governor equation is expressed as follows: ； in, Indicates relative dynamic torque; Indicates the relative flow rate of the branch pipe; , , These represent the relative opening of the turbine guide vanes. Turbine working head Relative deviation of turbine speed The corresponding turbine torque transmission coefficient; , , These represent the relative opening of the turbine guide vanes. Turbine working head Relative deviation of turbine speed The corresponding turbine flow transfer coefficient; This represents the inertial time constant of the water turbine; This indicates the load disturbance of the generator in the water turbine; This represents the self-regulating coefficient of the generator in the water turbine; , These represent the proportional gain and integral gain of the water turbine, respectively.

4. The method for modeling and simulating the transient process of a complex water conveyance and power generation system with multiple turbines in a single tunnel, as described in claim 2, is characterized in that... The dynamic equation of the water diversion tunnel is expressed as follows: ； The continuity equation for the pressure regulating chamber is expressed as: ； in, Indicates the relative flow rate of the water diversion tunnel The derivative; Represent the dynamic equation; This indicates the relative deviation of the turbine's rotational speed; This indicates the relative water level fluctuation in the surge tank; Indicates the dynamic coefficient of the water diversion tunnel; This represents the damping and inertia coefficient of the water diversion tunnel; Represents the boundary constraint function of the water diversion tunnel; This indicates the relative flow rate at the bifurcation point; This indicates the relative flow rate at the first-order bifurcation point; This represents the time constant of the pressure regulating chamber.

5. The method for modeling and simulating the transient process of a complex water conveyance and power generation system with multiple turbines in a single tunnel, as described in claim 2, is characterized in that... The dynamic equation for the main pressure pipeline is expressed as follows: ； The continuity equation for the flow at the bifurcation point is expressed as: ； The dynamic equations for each branch pipe connected to the main pressure pipeline are expressed as follows: ； in, Represents the relative flow rate at the bifurcation point. The derivative; Represent the dynamic equation; This indicates the relative deviation of the turbine's rotational speed; This indicates the relative water level fluctuation in the surge tank; Indicates the dynamic coefficient of the main pressure pipeline; This represents the damping and inertia coefficient of the main pressure pipeline; Represents the boundary constraint function for the main pressure pipeline; , These represent the relative speed deviations of the turbine relative to the turbine's operating head and the bifurcation pipe relative to the turbine's operating head, respectively. This indicates a branch pipe connected to the main pressure pipeline. Flow allocation coefficient; This indicates a branch pipe connected to the main pressure pipeline. relative flow The derivative; Indicates the number of branch pipes connected to the main pressure pipeline; , , These represent the branch pipes connected to the main pressure pipeline. Dynamic coefficients, damping and inertia coefficients, and boundary constraint functions.

6. The method for modeling and simulating the transient process of a complex water conveyance and power generation system with multiple turbines in a single tunnel, as described in claim 2, is characterized in that... The continuity equation for the flow at the first-order bifurcation point is expressed as: ； The dynamic equation for the secondary pressure pipeline is expressed as: ； ； The continuity equation for the flow at the second-order bifurcation point is expressed as: ； ； The dynamic equations for each branch pipe connected to the secondary pressure pipeline are expressed as follows: ； in, This indicates the relative flow rate at the first-order bifurcation point; This represents the relative flow rate at bifurcation point 1 (second-order bifurcation point). The derivative; This indicates the relative flow rate at the second-order bifurcation point 2. The derivative; , These represent the flow distribution coefficients at second-order bifurcation point 1 and second-order bifurcation point 2, respectively; Represent the dynamic equation; This indicates the relative deviation of the turbine's rotational speed; This indicates the relative water level fluctuation in the surge tank; , , These represent the dynamic coefficients, damping and inertia coefficients, and boundary constraint functions of the secondary pressure pipe 1, respectively. , These represent the relative speed deviations of the turbine relative to the turbine's operating head and the bifurcation pipe relative to the turbine's operating head, respectively. , , These represent the dynamic coefficients, damping and inertia coefficients, and boundary constraint functions of the secondary pressure pipe 2, respectively. This indicates the branch pipe connected to the secondary pressure pipeline 1. Flow allocation coefficient; This indicates the branch pipe connected to the secondary pressure pipeline 1. The relative flow rate; Indicates the number of branch pipes connected to secondary pressure pipe 1; This indicates the branch pipe connected to the secondary pressure pipe 2. Flow allocation coefficient; This indicates the branch pipe connected to the secondary pressure pipe 2. The relative flow rate; Indicates the number of branch pipes connected to secondary pressure pipe 2; This indicates the branch pipe connected to the secondary pressure pipeline 1. relative flow The derivative; , , These represent the branch pipes connected to the secondary pressure pipeline 1. Dynamic coefficients, damping and inertia coefficients, boundary constraint functions; This indicates the branch pipe connected to the secondary pressure pipe 2. relative flow The derivative; , , These represent the branch pipes connected to the secondary pressure pipeline 2. Dynamic coefficients, damping and inertia coefficients, and boundary constraint functions.

7. The method for modeling and simulating the transient process of a complex water conveyance and power generation system with multiple turbines in a single tunnel, as described in claim 2, is characterized in that... The drawing of the control logic block diagram includes: The governor's opening signal or on-site measured data, as well as the generator's unit speed signal, are connected to the turbine's input terminal. The turbine outputs the unit flow signal and the turbine torque signal. The turbine's output flow rate signal is connected to the input of the water intake system. The water intake system outputs the turbine's working head signal and feeds it back to the turbine's input. The turbine torque signal is connected to the generator input terminal. The generator outputs the unit speed signal and feeds it back to the turbine input terminal and the governor input terminal. The governor outputs the opening signal to the turbine based on the deviation between the unit speed signal and the set value, thus completing the drawing of the control logic block diagram.

8. The method for modeling and simulating the transient process of a complex water conveyance and power generation system with multiple turbines in a single tunnel, as described in claim 7, is characterized in that... Based on the initial operating boundary conditions of a complex hydroelectric power generation system with multiple generators in a single tunnel, dynamic simulation was performed on the simulation model, and the simulation results were obtained, including: If on-site measured data exists, the governor in the simulation model is disconnected, and the on-site measured turbine deflector opening data and nozzle opening data are used as inputs to the turbine. Dynamic simulation is then performed on the simulation model to obtain the simulation results. If no on-site measured data is available, the speed governor in the simulation model is connected. The speed governor outputs an opening signal to the turbine through the frequency step disturbance or power set disturbance at the input terminal, and performs dynamic simulation on the simulation model to obtain the simulation results.

9. A modeling and simulation device for the transient process of a complex water conveyance and power generation system with multiple turbines in a single tunnel, characterized in that, include: The model building module is used to: build models of the turbine units and the water diversion system in a complex water conveyance and power generation system with multiple turbines in one tunnel; The model transformation module is used to perform Laplace transform on the turbine generator model and the water diversion system model to obtain the transfer function of the turbine generator and the transfer function of the water diversion system. The block diagram drawing module is used to: connect the transfer functions of the turbine units and the transfer functions of the water diversion system into a control logic block diagram based on the signal flow direction and coupling relationship in a complex water conveyance and power generation system with multiple turbines in one tunnel; The model simulation module is used to: build a simulation model of the control logic block diagram, perform dynamic simulation on the simulation model based on the initial operating boundary conditions of the complex water conveyance and power generation system with multiple machines in one tunnel, and obtain simulation results.

10. A computer-readable storage medium having a computer program / instructions stored thereon, characterized in that, When the computer program / instruction is executed by the processor, it implements the steps of the method for modeling and simulating the transient process of a complex water conveyance and power generation system with multiple machines in a single tunnel as described in any of claims 1-8.

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