A method for simulating pressure parameters of nuclear power steam turbines

Abstract

The present invention discloses a method for simulating the pressure parameters of a nuclear power steam turbine, comprising the following steps: during the process of increasing the speed and load of the nuclear power steam turbine, the original real data is discretized and sampled, and the functional relationship between the speed and load and the real-time pressure value of the nuclear power steam turbine is obtained by logical curve fitting; the real startup process data of the nuclear power steam turbine is used as the initial value for the simulator to simulate, and the simulator obtains the pressure disturbance value under different theoretical working conditions by controlling the regulating valve, and the pressure disturbance value is the corresponding pressure fluctuation amount under the same working condition; the associated real-time pressure value and the pressure disturbance value are superimposed to obtain the final pressure value under the corresponding actual working condition, and the final pressure value is used as the data source for the subsequent upper-level analysis server. The nuclear power steam turbine pressure parameter simulation method provided by the present invention integrates and corrects the real nuclear power plant steam turbine pressure parameters, and is closer to the actual pressure measurement point change trend.

Description

Technical Field

[0001] The present invention relates to the technical field of steam turbine monitoring, and in particular to a nuclear power steam turbine pressure parameter simulation method. Background Art

[0002] Domestic research institutions and universities have conducted research on steam turbine pressure simulation, but most rely on experimental platforms such as MATLAB or LABVIEW to establish mathematical models and transfer functions for computer analysis, which falls within the realm of theoretical research. Theoretical pressure parameter simulations often employ mathematical models, which can lead to a certain degree of deviation and unreality from actual nuclear power turbine operating parameters, increasing the potential for bias in subsequent research.

[0003] Domestic and international power plant control system manufacturers such as ABB, Siemens, GE, Emerson, and Mitsubishi are also researching steam turbine simulation systems, focusing on implementing control logic on their own control system hardware platforms. These simulation models are often implemented through simple configurations, simulating speed, power, and valve management. These simulations are used to verify the correctness and usability of their own steam turbine control logic, serving as functional verification and testing. This type of simulation is severely limited, limited to simulating a few simple operating conditions, favoring qualitative analysis, lacking flexible combinations, and offering limited accuracy.

[0004] The disclosure of the above background technology content is only used to assist in understanding the inventive concept and technical solution of the present invention. It does not necessarily belong to the prior art of this patent application, nor does it necessarily provide technical guidance. In the absence of clear evidence that the above content has been disclosed before the filing date of this patent application, the above background technology should not be used to evaluate the novelty and creativity of this application. Summary of the Invention

[0005] In order to overcome the shortcomings of the existing technology, the present invention provides a nuclear power steam turbine pressure parameter simulation method, the specific technical solution is as follows: A nuclear power steam turbine pressure parameter simulation method, comprising the following steps:

[0006] During the speed-up and load-up process of the nuclear power steam turbine, the original real data is discretized and sampled, and the functional relationship between the speed and load and the real-time pressure value of the nuclear power steam turbine is obtained by logical curve fitting; the real startup process data of the nuclear power steam turbine is used as the initial value for simulation by the simulator, and the simulator obtains the pressure disturbance value under different theoretical working conditions by controlling the regulating valve. The pressure disturbance value is the corresponding pressure fluctuation amount under the same working condition. The associated real-time pressure value and the pressure disturbance value are superimposed to obtain the final pressure value under the corresponding actual working condition, and the final pressure value is used as the data source of the subsequent upper-level analysis server.

[0007] Furthermore, if the pressure fluctuation amount of the pressure parameter simulated by the simulator exceeds the preset value within the set time period, the pressure disturbance value is superimposed with the corresponding real-time pressure value to obtain the final pressure value under the corresponding actual working conditions; if the pressure fluctuation amount of the pressure parameter simulated by the simulator does not exceed the preset value within the set time period, the pressure disturbance value is recorded as 0.

[0008] Furthermore, the functional relationship between the speed and load of the nuclear power steam turbine and the real-time value of the pressure is as follows:

[0009] P t =f(OS,FT)=a﹡f1(OS)+b﹡f2(FT)

[0010] Where, P t is the real-time pressure value, OS is the current speed, FT is the current load, f1 and f2 are empirical fitting functions, and a and b are constants.

[0011] Furthermore, the average of the real-time pressure values ​​corresponding to n adjacent time points is taken and then superimposed with the pressure disturbance value corresponding to the last time point to obtain the final pressure value corresponding to the last time point.

[0012] Furthermore, the real-time pressure value includes the steam pressure before the first stage of the high-pressure cylinder, the steam pressure of the main steam valve, the exhaust pressure of the high-pressure cylinder, the internal pressure of the condenser and the steam inlet pressure of the low-pressure cylinder. The nuclear power steam turbine actually sets pressure parameter monitoring points before the first stage of the high-pressure cylinder, the main steam valve, the high-pressure cylinder, the condenser and the air inlet of the low-pressure cylinder.

[0013] Furthermore, if the pressure fluctuation of the simulator at two consecutive time points exceeds 1 MPa, the pressure disturbance value is superimposed on the corresponding real-time pressure value to obtain the final pressure value under the corresponding actual working condition.

[0014] Furthermore, the speed and load settings of the simulator during simulation are consistent with the speed and load settings of the nuclear power steam turbine.

[0015] Furthermore, the simulator realizes pressure parameter simulation under bypass fully open, bypass fully closed or boiler feed water working conditions by controlling the regulating valve.

[0016] Furthermore, the working conditions simulated by the simulator include engaging the brake, rushing, warming up, rated speed, speed increase, and loading.

[0017] Furthermore, the simulator is based on a nuclear power steam turbine DEH control system.

[0018] Compared with the existing technology, the present invention has the following advantages: based on the operating data of a real nuclear power plant turbine, it organically combines simulation and practical application, uses mathematical models as the simulation object, uses real operating data as the basis of simulation, and integrates real scenarios of control simulation to improve the accuracy of the final pressure parameter simulation. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 1 is a schematic diagram of a process framework of a nuclear power steam turbine pressure parameter simulation method provided by an embodiment of the present invention;

[0020] Figure 2 1 is a schematic diagram of a curve of a fitting function f1 in a nuclear power steam turbine pressure parameter simulation method provided by an embodiment of the present invention;

[0021] Figure 3 1 is a schematic diagram of a curve of a fitting function f2 in a nuclear power steam turbine pressure parameter simulation method provided by an embodiment of the present invention;

[0022] Figure 4 1 is a schematic diagram of a pressure parameter simulation interface in a nuclear power steam turbine pressure parameter simulation method provided by an embodiment of the present invention;

[0023] Figure 5 It is a schematic diagram of a pressure curve in the nuclear power steam turbine pressure parameter simulation method provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0024] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0025] It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and the accompanying drawings are used to distinguish similar items and are not necessarily used to describe a particular order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate, such that the embodiments of the present invention described herein can be implemented in sequences other than those illustrated or described herein. Furthermore, the terms "including," "having," and any variations thereof are intended to cover non-exclusive inclusions.

[0026] In one embodiment of the present invention, a method for simulating nuclear power turbine pressure parameters is provided, comprising the following steps: during the speed and load increase process of the nuclear power turbine, the original real data is discretized and sampled, and the functional relationship between the speed and load and the real-time pressure value of the nuclear power turbine is obtained by logical curve fitting, i.e., a pressure conversion algorithm; the real startup process data of the nuclear power turbine is used as the initial value for the simulator to simulate, and the simulator is based on the nuclear power turbine DEH control system, which controls the regulating valve to obtain the pressure disturbance value under different theoretical working conditions, and the pressure disturbance value is the corresponding pressure fluctuation amount under the same working condition. The associated real-time pressure value and the pressure disturbance value are superimposed to obtain the final pressure value under the corresponding actual working condition, and the final pressure value is used as the data source for the subsequent upper-level analysis server. It should be noted that the speed and load settings of the simulator during simulation are consistent with the speed and load settings of the nuclear power turbine in real time.

[0027] Among them, if the pressure fluctuation of the pressure parameter simulated by the simulator exceeds the preset value within the set time period, the pressure disturbance value is superimposed with the corresponding real-time pressure value to obtain the final pressure value under the corresponding actual working conditions; if the pressure fluctuation of the pressure parameter simulated by the simulator does not exceed the preset value within the set time period, the pressure disturbance value is 0.

[0028] See also Figure 1 The pressure parameter simulated by the simulator fluctuates beyond the preset value within the set time period. This further includes three situations, which will affect the real-time pressure value obtained by the pressure conversion algorithm. The three situations are as follows:

[0029] (1) Large pressure fluctuations: The peak-to-peak value of the maximum pressure fluctuation is >2 MPa;

[0030] (2) Step pressure fluctuation: At a certain moment, the pressure suddenly increases by an increment of >1 MPa;

[0031] (3) Irregular pressure fluctuations: sudden changes in pressure, such as a momentary 0 or a continuous increase;

[0032] The nuclear power steam turbine adopts a program compiled by a discrete control system. The program is a classic startup curve to obtain the corresponding real data. Based on this data, the functional relationship between the speed and load of the nuclear power steam turbine and the real-time pressure value is obtained as follows:

[0033] P t =f(OS,FT)=a﹡f1(OS)+b﹡f2(FT)

[0034] Where, P t is the real-time pressure value, OS is the current speed, FT is the current load, f1 and f2 are empirical fitting functions, see Figure 2 and Figure 3 , a and b are constants, and the coefficients of a and b are generally selected between 0.9-1.1. The default values ​​are a=1 and b=1.

[0035] In a preferred embodiment, the average of the real-time pressure values ​​corresponding to n adjacent time points is taken and then superimposed with the pressure disturbance value corresponding to the last time point to obtain the final pressure value corresponding to the last time point.

[0036] When n=4, calculate the average pressure value of the first four moments and add the pressure disturbance value. The calculation formula is as follows:

[0037]

[0038] P s =f(x)=|x|

[0039] Where, P f is the final pressure value, and x is the pressure disturbance value.

[0040] In one embodiment of the present invention, a matching design is performed based on a hard simulation model, and a simulation algorithm is used to simulate the entire process of a nuclear power steam turbine from startup parameter setting and impulse start to full load. The simulator is based on the domestic mainstream nuclear power steam turbine DEH control system, and is targeted in design based on the actual parameters and operating conditions of the model. It mainly realizes steam turbine startup control, grid connection control and various test operations. In the process of simulating pressure parameter changes, the simulation data is transmitted to the upper server through communication. The pressure parameter simulation interface is as follows: Figure 4 shown.

[0041] The nuclear power steam turbine pressure simulator simulates the entire process of turbine control, from turbine shutdown, run-up, warm-up, over-criticality, to rated speed, and then speed increase and load application. This is achieved by controlling the regulating valves and includes protection logic to prevent overspeeding of the simulated turbine. Furthermore, the turbine operating parameter simulator provides parameter simulation. Based on empirical values ​​from past operations, the simulator simulates the changing trends of various parameters during the start-up and run-up phases and after load application, including pressure parameters such as main steam pressure and steam pressure parameters of key turbine components. The simulator also offers the ability to perturb certain parameters, enhancing simulation accuracy and aligning it more closely with real-world operating conditions. Main steam pressure and reheater pressure can be manipulated to fluctuate slightly, significantly, and with sudden increases or decreases. This parameter perturbation allows for simulation of field parameter variations.

[0042] This embodiment is based on big data and collects pressure data from numerous nuclear power steam turbines, including pressure changes during warm-up, start-up, constant speed, and load. Based on the changing characteristics of each pressure measurement point under abnormal operating conditions, an algorithm is summarized to develop a pressure parameter algorithm for the corresponding position.

[0043] The real-time pressure value includes the steam pressure before the first stage of the high-pressure cylinder, the steam pressure of the main steam valve, the exhaust pressure of the high-pressure cylinder, the internal pressure of the condenser and the steam inlet pressure of the low-pressure cylinder. The nuclear power steam turbine is actually provided with pressure parameter monitoring points before the first stage of the high-pressure cylinder, the main steam valve, the high-pressure cylinder, the condenser and the air inlet of the low-pressure cylinder. The specific arrangement of the pressure measurement points of the nuclear power steam turbine is as follows:

[0044] Serial number name Range unit Remark 1 Steam pressure before the first stage of high-pressure cylinder (regulation end 1) 0-10 Mpa 2 Steam pressure before the first stage of high-pressure cylinder (regulation end 2) 0-10 Mpa 3 Steam pressure before the first stage of high-pressure cylinder (electrical terminal 1) 0-10 Mpa 4 Steam pressure before the first stage of high-pressure cylinder (electrical terminal 2) 0-10 Mpa 5 Main steam valve steam pressure (L) 0-10 Mpa 6 Main steam valve steam pressure (R) 0-10 Mpa 7 High pressure cylinder exhaust pressure (electrical end) 0-2 Mpa 8 High pressure cylinder exhaust pressure (regulation end) 0-2 Mpa 9 Condenser #1 Vacuum 0-2 Mpa 10 Condenser #2 Vacuum 0-2 Mpa 11 MSR A inlet steam pressure to low pressure cylinder #1 0-10 Mpa 12 MSR A inlet steam pressure to low pressure cylinder #2 0-10 Mpa 13 MSR B inlet steam pressure to low pressure cylinder #1 0-10 Mpa 14 MSR B into the low pressure cylinder #2 steam pressure 0-10 Mpa

[0045] The pressure design in the nuclear power steam turbine pressure parameter simulation method provided by the present invention uses the real startup process data of the nuclear power plant as the initial value of the simulation. At the same time, during the speed increase and load increase process, the original real data is discretized and sampled, and the simulation is realized by logical curve fitting. Figure 5 Taking the main steam pressure and temperature data as an example, the initial setting for the first stage is 7.5 MPa, which maintains a stable state. In the middle stage, a small fluctuation is selected, and upper and lower limits are set. The main steam pressure begins to fluctuate slightly. This process load reflects the relatively stable pressure and temperature state of the main steam parameters during nuclear power plant startup. With the main steam pressure fluctuating slightly, the high-pressure first-stage pressure begins to follow the main steam pressure fluctuations, demonstrating the pressure transfer characteristic and conforming to objective reality. The initial value of the outlet pressure of the two MSRs is 7 MPa. Depending on the actual situation, the same setting method as the main steam pressure can be used.

[0046] The nuclear power steam turbine pressure parameter simulation method provided by the present invention can perform flexible pressure simulation configuration and simulate pressure changes under different models and different operating conditions; it can perform multi-parameter association, such as speed, load, unit thermal state, etc., and has strong versatility; it can perform disturbance design input, realize simulation analysis of abnormal operating conditions, fault reproduction, etc.

[0047] The above description is only a preferred embodiment of the present invention and does not limit the scope of the patent. Any equivalent structure or equivalent process transformation made by using the contents of the description and drawings of the present invention, directly or indirectly applied in other related technical fields, is also included in the scope of patent protection of the present invention.

Claims

1. A nuclear power steam turbine pressure parameter simulation method, characterized in that: The following steps are involved: During the speed-up and load-up process of the nuclear power steam turbine, the original real data is discretized and sampled, and the functional relationship between the speed and load and the real-time pressure value of the nuclear power steam turbine is obtained by logical curve fitting; the real startup process data of the nuclear power steam turbine is used as the initial value for simulation by the simulator, and the simulator obtains the pressure disturbance value under different theoretical working conditions by controlling the regulating valve. If the pressure fluctuation amount of the pressure parameter simulated by the simulator exceeds the preset value within the set time period, the pressure disturbance value is the corresponding pressure fluctuation amount under the same working condition. The associated real-time pressure value and the pressure disturbance value are superimposed to obtain the final pressure value under the corresponding actual working condition, and the final pressure value is used as the data source for the subsequent upper-level analysis server.

2. The nuclear power steam turbine pressure parameter simulation method according to claim 1, characterized in that: The pressure disturbance value is superimposed on the corresponding real-time pressure value to obtain the final pressure value under the corresponding actual working conditions; if the pressure fluctuation amount of the pressure parameter simulated by the simulator does not exceed the preset value within the set time period, the pressure disturbance value is recorded as 0.

3. The nuclear power steam turbine pressure parameter simulation method according to claim 1, characterized in that: The functional relationship between the nuclear power steam turbine speed and the real-time pressure value of the load is as follows: P t =f(OS,FT)=a﹡f1(OS)+b﹡f2(FT) Where, P t is the real-time pressure value, OS is the current speed, FT is the current load, f1 and f2 are empirical fitting functions, and a and b are constants.

4. The nuclear power steam turbine pressure parameter simulation method according to claim 1, characterized in that: The average of the real-time pressure values ​​corresponding to n adjacent time points is taken and then superimposed with the pressure disturbance value corresponding to the last time point to obtain the final pressure value corresponding to the last time point.

5. The nuclear power steam turbine pressure parameter simulation method according to claim 1, characterized in that: The real-time pressure value includes the steam pressure before the first stage of the high-pressure cylinder, the steam pressure of the main steam valve, the exhaust pressure of the high-pressure cylinder, the internal pressure of the condenser and the steam inlet pressure of the low-pressure cylinder. The nuclear power steam turbine is equipped with pressure parameter monitoring points before the first stage of the high-pressure cylinder, the main steam valve, the high-pressure cylinder, the condenser and the air inlet of the low-pressure cylinder.

6. The nuclear power steam turbine pressure parameter simulation method according to claim 1, characterized in that: If the pressure fluctuation of the simulator at two consecutive time points exceeds 1 MPa, the pressure disturbance value is superimposed on the corresponding real-time pressure value to obtain the final pressure value under the corresponding actual working conditions.

7. The nuclear power steam turbine pressure parameter simulation method according to claim 1, characterized in that: The speed and load settings of the simulator during simulation are consistent with the speed and load settings of the nuclear power steam turbine.

8. The nuclear power steam turbine pressure parameter simulation method according to claim 1, characterized in that: The simulator realizes pressure parameter simulation under bypass fully open, bypass fully closed or boiler feed water working conditions by controlling the regulating valve.

9. The nuclear power steam turbine pressure parameter simulation method according to claim 8, characterized in that: The working conditions simulated by the simulator include brake engagement, rush start, warm-up, rated speed, speed increase, and load loading.

10. The nuclear power steam turbine pressure parameter simulation method according to claim 1, characterized in that: The simulator is based on a nuclear power steam turbine DEH control system.

Images