Multi-nozzle impulse turbine variable nozzle process regulator and regulation method

Abstract

This application proposes a regulator and regulation method for a multi-nozzle impulse turbine with variable nozzle process, relating to the field of hydropower station operation control technology. The device includes a PID controller and multiple dual-opening control controllers connected to multiple nozzles. Each dual-opening control controller includes a first opening controller and a second opening controller, and the multiple first opening controllers are connected to the PID controller. Using the above scheme, this application can achieve stable unit parameters during the variable nozzle process of a multi-nozzle impulse turbine.

Description

Technical Field

[0001] This application relates to the field of hydropower station operation control technology, and in particular to a multi-nozzle impulse turbine variable nozzle process regulator and regulation method. Background Technology

[0002] Currently, most hydropower station regulation systems use PID speed governors, which adjust the flow rate of the turbine when the load of the power system changes or the unit speed deviates, so as to achieve a new balance between the turbine hydraulic torque and the generator load resistance torque, and maintain the frequency (unit speed) within the specified range.

[0003] In recent years, plans have been proposed to develop hydropower in the lower reaches of the Yarlung Tsangpo River. The lower reaches of the Yarlung Tsangpo River are generally characterized by high head and large flow rates. Developing large-scale impulse turbine units is a good solution to address these characteristics.

[0004] For impulse turbine units, conventional PID controllers can be used for regulation during normal operation. However, unlike mixed-flow turbine units, multi-nozzle impulse turbine units require different numbers of nozzles depending on the output range to ensure high efficiency and efficient and reliable nozzle opening regulation. Therefore, during load increases or decreases, the number of nozzles needs to be increased or decreased, and selecting a suitable nozzle opening change pattern during this process is challenging. If a good change pattern cannot be selected during the change of the number of nozzles, it may lead to large fluctuations in the system, causing drastic changes in unit speed (output). Summary of the Invention

[0005] This application aims to at least partially address one of the technical problems in the related art.

[0006] Therefore, the first objective of this application is to propose a multi-nozzle impulse turbine variable nozzle process regulator, which solves the problem that existing methods cannot accurately determine the variation law, resulting in large system fluctuations and drastic changes in unit speed. It can accurately adjust the nozzles and ensure the stability of unit parameters during the multi-nozzle impulse turbine variable nozzle process.

[0007] The second objective of this application is to propose a method for regulating the variable nozzle process of a multi-nozzle impact turbine.

[0008] To achieve the above objectives, the first aspect of this application provides a multi-nozzle impact turbine variable nozzle process regulator, comprising: a PID controller and a plurality of dual-opening control controllers connected to a plurality of nozzles, each dual-opening control controller including a first opening controller and a second opening controller, and the plurality of first opening controllers being connected to the PID controller.

[0009] The multi-nozzle impact turbine variable nozzle process regulator of this application uses a dual-path controller to adjust the opening change pattern of each nozzle, so that the system can maintain stable operation when the number of nozzles changes, thereby reducing system fluctuations and potential hazards.

[0010] Optionally, in one embodiment of this application, the PID controller includes a comparator, a PID regulator, and a plurality of first proportional elements connected in series. The plurality of first proportional elements are connected in parallel. Each proportional element is connected to a corresponding first opening controller. Each first opening controller, together with a second opening controller, controls the opening change of a nozzle.

[0011] Optionally, in one embodiment of this application, the PID controller further includes a measuring device connected to the comparator and the impulse generator respectively, and the PID regulator includes a second proportional element, an integral operation element, and a derivative operation element connected in parallel.

[0012] To achieve the above objectives, a second aspect of this application proposes a method for regulating the opening of multiple nozzles in a multi-nozzle impulse turbine. The method involves adjusting the opening of multiple nozzles using a multi-nozzle impulse turbine variable nozzle process regulator. The method includes: measuring the speed of the impulse turbine unit using a measuring device; determining the adjustment amount of the first opening regulator in each dual-opening control controller based on the measured unit speed using a PID controller, and determining the adjustment amount of the second opening regulator in each second opening controller based on a given opening change pattern; and adjusting the opening of the corresponding nozzle using each dual-opening control controller based on the determined adjustment amount.

[0013] Optionally, in one embodiment of this application, the transfer function of the PID controller is expressed as:

[0014]

[0015] Among them, K p This represents the coefficient of the second proportional element. This represents the differential operation. K represents the integral operation stage. D T is the coefficient of the differential element. D K is the time constant of the differential element. I Let S be the coefficient of the integral element in the PID controller, and S be a complex variable defined as follows: For the time-domain function f(t), its Laplace transform is as follows:

[0016]

[0017] Where e is the natural logarithm.

[0018] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0019] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

[0020] Figure 1 This is a schematic diagram of the structure of a multi-nozzle impulse turbine variable nozzle process regulator provided in Embodiment 1 of this application;

[0021] Figure 2 This is a schematic diagram of a six-nozzle impulse power plant system according to an embodiment of this application;

[0022] Figure 3 This is a block diagram of a multi-nozzle impulse turbine regulator according to an embodiment of this application;

[0023] Figure 4 This is a schematic diagram illustrating the variation of nozzle opening during the simulation process of an embodiment of this application;

[0024] Figure 5 This is a schematic diagram of the flow rate of each nozzle during the simulation process of an embodiment of this application;

[0025] Figure 6 This is a schematic diagram illustrating the relative speed change of the unit during the simulation process of an embodiment of this application;

[0026] Figure 7 This is a schematic diagram illustrating the relative flow rate variation of the unit during the simulation process of an embodiment of this application;

[0027] Figure 8 This is a schematic diagram illustrating the variation of the unit's head during the simulation process of an embodiment of this application;

[0028] Figure 9 This is a flowchart illustrating a method for adjusting the nozzle process of a multi-nozzle impact turbine, as provided in an embodiment of this application. Detailed Implementation

[0029] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0030] When the load changes, the number of nozzles in an impulse turbine needs to be varied according to the output range to ensure high efficiency and keep the nozzles within the appropriate opening range. If the nozzle opening variation pattern is not properly selected during the nozzle variation process, it will lead to drastic fluctuations in turbine speed or output, and may also cause drastic pressure changes in the piping system. Therefore, a regulator is required for adjustment. This application provides a control method for a variable nozzle number process.

[0031] The following description, with reference to the accompanying drawings, describes an embodiment of a multi-nozzle impact turbine variable nozzle process regulator and regulation method.

[0032] Figure 1 This is a schematic diagram of the structure of a multi-nozzle impact turbine variable nozzle process regulator provided in Embodiment 1 of this application.

[0033] like Figure 1 As shown, the multi-nozzle impulse turbine variable nozzle process regulator includes a PID controller and multiple dual-opening control controllers connected to multiple nozzles. Each dual-opening control controller includes a first opening controller and a second opening controller, and the multiple first opening controllers are connected to the PID controller.

[0034] Specifically, each nozzle is controlled by a dual-opening controller. One of the dual-opening controllers is a PID controller that performs negative feedback adjustment based on changes in the unit's speed, while the other controller directly provides the opening change pattern. The two controllers work together to control the nozzle opening, thereby achieving rapid and smooth adjustment of the speed and output to a stable state during changes in the number of nozzles.

[0035] Specifically, in the negative feedback control system controlled by the PID controller, the dual-aperture controller adjusts the given opening change pattern to maintain stable system operation. This process includes:

[0036] Input reference value x r x r The difference between the comparator output and the measured value from the measuring device, representing the rotational speed or output power, is input to the PID controller to output the adjustment quantity. The PID controller consists of a proportional element, an integral element, and a derivative element connected in parallel. The output adjustment quantity, after passing through the proportional element, is input to the opening controller a in the dual-opening controller. This, together with the opening controller b, which has a given opening change pattern, acts to control the nozzle opening, thus achieving the regulation of the variable nozzle process. The proportional element (digital switch) before the opening controller a is used to adjust the on / off state of the nozzle and provide manual adjustment functionality.

[0037] Specifically, when the opening of a nozzle is controlled by two opening controllers, the control process can be accomplished through the superposition of digital or analog signals, or through the superposition of mechanical motions. This is achieved by adjusting the proportional element K connected to the opening controller before the PID controller. pi The multiplication factor is used to control whether the nozzle opening adjustment is running and to manually adjust the opening change.

[0038] Specifically, considering the relationship between torque and speed as a traditional first-order inertial element, the measuring device can be equivalent to a first-order inertial element to tune the PID parameters during theoretical calculations. Then, the theoretically tuned PID coefficients are substituted into the simulation calculations, and after adjustment, better PID parameters are obtained for simulation calculations.

[0039] The multi-nozzle impact turbine variable nozzle process regulator of this application uses a dual-path controller to adjust the opening change pattern of each nozzle, so that the system can maintain stable operation when the number of nozzles changes, thereby reducing system fluctuations and potential hazards.

[0040] Optionally, in one embodiment of this application, the PID controller includes a comparator, a PID regulator, and a plurality of first proportional elements connected in series. The plurality of first proportional elements are connected in parallel, and each proportional element is connected to a corresponding first opening controller. Each first opening controller, together with a second opening controller, controls the opening change of a nozzle.

[0041] Specifically, the negative feedback loop consists of the following components: one comparator, one PID controller, n proportional elements, n dual-aperture controllers, and a measuring device. The PID controller comprises an integral element (KIS) and a derivative element (KIS). It is composed of the proportional element Kp0 connected in parallel.

[0042] Specifically, the transfer function of the PID controller is:

[0043]

[0044] Optionally, in one embodiment of this application, the PID controller further includes a measuring device connected to the comparator and the impulse generator respectively, and the PID regulator includes a second proportional element, an integral operation element, and a derivative operation element connected in parallel.

[0045] The following is a detailed description of the multi-nozzle impulse turbine variable nozzle process regulator of this embodiment through specific examples.

[0046] This embodiment applies to a six-nozzle impulse power station system, which consists of an upstream reservoir, a surge tank, two emergency control valves, and two impulse turbine units. Its system diagram is shown below. Figure 2 As shown, the rated parameters are listed in Table 1. The block diagram of the multi-nozzle impulse turbine regulator in this embodiment is shown below. Figure 3 As shown.

[0047] Table 1 Main parameters of the unit

[0048]

[0049]

[0050] Figure 3 The following is a block diagram of the control system for an n-nozzle impulse turbine unit. Figure 3 The variables in the regulator block diagram are explained as follows:

[0051] x r This is a reference value for the control quantity (relative speed);

[0052] x is the control variable (relative speed of the unit);

[0053] K P This refers to the proportional element coefficient in a PID controller;

[0054] K I The integral coefficient in the PID controller;

[0055] K D The coefficient of the derivative element in the PID controller;

[0056] T D This is the time constant of the derivative element in the PID controller;

[0057] K Pi This is the adjustment ratio coefficient before the i-th adjusting nozzle;

[0058] x r This is the difference between the measured rotational speed and the reference value.

[0059] e is the output regulation value of the PID controller;

[0060] The transfer function of the PID controller is:

[0061]

[0062] PID control variables include:

[0063]

[0064] Perform inverse Laplace transform

[0065]

[0066] In the simulation calculations for this power plant, the PID controller parameters are set as follows: K P =0.75, K I =0.45, K D =0.3, T D =0.1s. For the simulation process of transitioning from two nozzles to three nozzles, take K. P1 =K P2 =K P3 =K P4 =1,K P5 =K P6 =0.

[0067] The designed regulator model was incorporated into the simulation program, and simulation calculations were performed on the entire system. In the calculations, mathematical models were established for the pipelines, surge tanks, and power plant units based on the actual system's design parameters and their inherent nonlinear characteristics. The calculation conditions were as follows: the unit initially operated stably with two nozzles, and the initial openings of a1 and a2 were equal to the stable operating opening y0 of the two nozzles. At t=0, the number of nozzles began to change, and the opening controller a was controlled linearly. i At time t = t1, a2 becomes 0, and a1, a3, and a4 change from their initial openings to the preset three-nozzle operating opening y1. That is, the change pattern is y... i =k i t+b i The specific details are shown in Table 2. The PID controller is used to adjust b. i Finally, it switches to stable operation with all three nozzles running at the same speed. This controller is used in simulation calculations to control the turbine runner speed.

[0068] Table 2. Parameters showing the variation pattern of the opening degree controller.

[0069]

[0070] In this simulation example, we take y0 = 0.7562, y1 = 0.4192, and t1 = 20s.

[0071] Simulation results are shown in Table 3 and Figure 4-8 As shown, Figure 4 This is a schematic diagram illustrating the variation of nozzle opening during the simulation process. Figure 5 This is a schematic diagram of the flow rate of each nozzle during the simulation process. Figure 6 This is a schematic diagram illustrating the change in the relative speed of the unit during the simulation process. Figure 7 This is a schematic diagram illustrating the relative flow rate variation of the unit during the simulation process. Figure 8 This is a schematic diagram illustrating the variation of the unit's head during the simulation process.

[0072] Table 3 Results

[0073]

[0074] To achieve the above embodiments, this application also proposes a method for regulating the variable nozzle process of a multi-nozzle impulse turbine, which regulates the opening of multiple nozzles using the aforementioned variable nozzle process regulator for the multi-nozzle impulse turbine.

[0075] Figure 9 This is a flowchart illustrating a method for adjusting the nozzle process of a multi-nozzle impact turbine, as provided in an embodiment of this application.

[0076] like Figure 9 As shown, the method for adjusting the nozzle process of a multi-nozzle impulse turbine includes the following steps:

[0077] Step 901: Measure the speed of the impulse turbine unit using a measuring device;

[0078] Step 902: Using a PID controller, determine the adjustment amount of the first opening regulator in each dual opening control controller based on the measured unit speed, and determine the adjustment amount of the second opening regulator in each second opening control based on the given opening change law.

[0079] Step 903: Adjust the opening of the corresponding nozzle based on a determined adjustment amount using each dual-opening adjustment controller.

[0080] Furthermore, in the embodiments of this application, the transfer function of the PID controller is expressed as:

[0081]

[0082] Among them, K p This represents the coefficient of the second proportional element. This represents the differential operation. K represents the integral operation stage. D T is the coefficient of the differential element. D K is the time constant of the differential element. I Let S be the coefficient of the integral element in the PID controller, and S be a complex variable defined as follows: For the time-domain function f(t), its Laplace transform is as follows:

[0083]

[0084] Where e is the natural logarithm.

[0085] It should be noted that the foregoing explanation of the embodiment of the variable nozzle process regulation method for a multi-nozzle impulse turbine also applies to the variable nozzle process regulation device for a multi-nozzle impulse turbine in this embodiment, and will not be repeated here.

[0086] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0087] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0088] Any process or method description in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or more executable instructions for implementing custom logic functions or processes, and the scope of the preferred embodiments of this application includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as should be understood by those skilled in the art to which embodiments of this application pertain.

[0089] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Alternatively, the computer-readable medium may be paper or other suitable media on which the program can be printed, since the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.

[0090] It should be understood that various parts of this application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented using software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0091] Those skilled in the art will understand that all or part of the steps of the methods in the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, the program includes one or a combination of the steps of the method embodiments.

[0092] Furthermore, the functional units in the various embodiments of this application can be integrated into a processing module, or each unit can exist physically separately, or two or more units can be integrated into a module. The integrated module can be implemented in hardware or as a software functional module. If the integrated module is implemented as a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium.

[0093] The storage medium mentioned above can be a read-only memory, a disk, or an optical disk, etc. Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of this application.

Claims

1. A multi-nozzle impact turbine variable nozzle process regulator, characterized in that, It includes a PID controller and multiple dual-opening control controllers connected to multiple nozzles. Each dual-opening control controller includes a first opening controller and a second opening controller, and the multiple first opening controllers are connected to the PID controller. The PID controller includes a comparator, a PID regulator, and multiple first proportional elements connected in series. The multiple first proportional elements are connected in parallel. Each proportional element is connected to a corresponding first opening controller. Each first opening controller, together with a second opening controller, controls the opening change of a nozzle. The PID controller also includes a measuring device, which is connected to the comparator and the impulse turbine unit respectively, and is used to measure the rotational speed of the impulse turbine unit; The PID controller includes a second proportional element, an integral operation element, and a derivative operation element connected in parallel. The PID controller determines the adjustment amount of the first opening controller in each dual-opening control controller based on the measured unit speed. The adjustment amount of the second opening controller in each dual opening control is determined based on a given opening change pattern; The transfer function of the PID controller is expressed as follows: in, This represents the coefficient of the second proportional element. This represents the differential operation. This indicates the integral operation stage. The coefficients of the differential element, The time constant of the differential element, Let S be the coefficient of the integral element in the PID controller, and S be a complex variable defined as follows: For the time-domain function f(t), its Laplace transform is as follows: Where e is the natural logarithm.

2. A method for adjusting the nozzle process of a multi-nozzle impulse turbine, characterized in that, The method of adjusting the opening degree of multiple nozzles using the multi-nozzle impulse turbine variable nozzle process regulator as described in claim 1 includes the following steps: The rotational speed of the impulse turbine unit is measured using the aforementioned measuring device; The PID controller determines the adjustment amount of the first opening controller in each dual-opening control controller based on the measured unit speed, and determines the adjustment amount of the second opening controller in each dual-opening control controller based on the given opening change law. Each dual-aperture adjustment controller adjusts the opening of the corresponding nozzle based on a determined adjustment amount.

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