A steam turbine speed regulation method and system based on the flow characteristics of a valve

Abstract

The present invention provides a steam turbine speed regulation method and system based on valve flow characteristics, belonging to the technical field of steam turbine speed regulation. A speed regulation system is used to regulate the speed of the steam turbine. The speed regulation system includes 4 sequence valves. The steam turbine speed regulation method includes: obtaining a comprehensive valve position command; for any one of the sequence valves, determining the valve position command of the sequence valve according to the comprehensive valve position command; adjusting the opening degree of the corresponding sequence valve according to the valve position commands of each sequence valve so as to regulate the speed of the steam turbine. When performing the response curve simulation of the slip disturbance, it can be closer to the actual link characteristics of the power plant, obtain a more real and accurate response process curve, reflect the influence of the flow characteristics of the nonlinear link on the steam turbine speed regulation ability, and further improve the speed regulation accuracy.

Description

Technical Field

[0001] The present invention relates to the field of steam turbine speed regulation, and particularly to a steam turbine speed regulation method and system based on valve flow characteristics. Background Art

[0002] Due to the large-scale development of new energy and the access of wind power, photovoltaic energy storage to the power grid, a large number of new power electronic devices are connected, and the power grid shows a trend of low inertia and weak damping, with poor stability. The control basis and operation mechanism of the power system have changed. New energy power generation has the characteristics of randomness, intermittency, and volatility. When the power grid encounters load mutations or other situations that cause power grid oscillations, it will be very difficult to stabilize, and may even not stop, resulting in serious consequences.

[0003] At present, the research on low-frequency oscillation of units is based on typical speed regulation systems for simulation and analysis. The parameter optimization process of the speed regulation systems involved in existing research is likely to have an adverse impact on the frequency modulation response performance of the units. In addition, the operating conditions of thermal power units vary greatly, and there are many reasons on the prime mover side that may induce low-frequency oscillation of the units. The parameters set according to a single operating condition are difficult to show the expected performance, resulting in an unsatisfactory effect on steam turbine speed regulation. Summary of the Invention

[0004] The purpose of the present invention is to provide a steam turbine speed regulation method and system based on valve flow characteristics, which can improve the accuracy of steam turbine speed regulation.

[0005] To achieve the above purpose, the present invention provides the following solutions:

[0006] A steam turbine speed regulation method based on valve flow characteristics uses a speed regulation system to regulate the steam turbine. The speed regulation system includes 4 sequence valves. The steam turbine speed regulation method based on valve flow characteristics includes:

[0007] Obtain a comprehensive valve position command;

[0008] For any sequence valve, determine the valve position command of the sequence valve according to the comprehensive valve position command;

[0009] Adjust the opening of the corresponding sequence valve according to the valve position commands of each sequence valve to regulate the steam turbine.

[0010] Optionally, the steam turbine speed regulation method based on valve flow characteristics further includes:

[0011] Sum the valve position commands of each sequence valve to obtain a total valve position command;

[0012] Convert the total valve position command into main steam flow using a first conversion coefficient; the first conversion coefficient is the conversion coefficient between the valve position command and steam flow.

[0013] Optionally, determining the valve control instruction of the sequence valve according to the comprehensive valve position instruction specifically includes:

[0014] Converting the comprehensive valve position instruction into a comprehensive valve control instruction by using a second conversion coefficient; the second conversion coefficient is the conversion coefficient between the valve position instruction and the valve control instruction;

[0015] Performing iterative calculation on the comprehensive valve control instruction by using the non-linear characteristic parameters of the sequence valve to obtain the initial valve control instruction of the sequence valve;

[0016] Determining the valve control instruction of the sequence valve according to the comprehensive valve control instruction, the opening threshold of the sequence valve, and the initial valve control instruction of the sequence valve.

[0017] Optionally, performing iterative calculation on the comprehensive valve control instruction by using the non-linear characteristic parameters of the sequence valve to obtain the initial valve control instruction of the sequence valve, specifically including:

[0018] Determining the first valve control instruction of the sequence valve according to the non-linear characteristic parameters of the sequence valve and the comprehensive valve control instruction;

[0019] For the nth iteration, determining the (n + 1)th valve control instruction of the sequence valve according to the non-linear characteristic parameters of the sequence valve, the comprehensive valve control instruction, and the nth valve control instruction of the sequence valve; 0 < n;

[0020] Judging whether n is equal to the iteration threshold. If so, the (n + 1)th valve control instruction is the initial valve control instruction of the sequence valve; otherwise, perform the (n + 1)th iteration.

[0021] Optionally, the non-linear characteristic parameters of the sequence valve include a first constant, a second constant, and a third constant;

[0022] Using the formula D CV1 ′ = C2·(D CV - C1)+ C3 to determine the first valve control instruction of the sequence valve; where C1 is the first constant, C2 is the second constant, C3 is the third constant, D CV is the comprehensive valve control instruction, and D CV1 ′ is the first valve control instruction of the sequence valve.

[0023] Optionally, determining the valve control instruction of the sequence valve according to the comprehensive valve control instruction, the opening threshold of the sequence valve, and the initial valve control instruction of the sequence valve specifically includes:

[0024] Determine whether the combined throttle valve command is less than or equal to the opening threshold of the sequence valve. If so, determine the throttle valve command of the sequence valve according to the initial throttle valve command of the sequence valve using a first function; otherwise, determine the throttle valve command of the sequence valve according to the initial throttle valve command of the sequence valve using a second function. The first function and the second function are functions determined in advance to make the throttle valve command of the sequence valve within the non-linear range of the sequence valve.

[0025] Optionally, the obtaining of the combined valve position command specifically includes:

[0026] Collect the current steam pressure, current speed, and current steam flow of the steam turbine;

[0027] According to the current steam pressure, the current speed, and the current steam flow, use a PID controller to determine the combined valve position command.

[0028] To achieve the above object, the present invention also provides the following solution:

[0029] A steam turbine speed control system based on valve flow characteristics, connected to the speed control system of the steam turbine. The speed control system includes 4 sequence valves. The steam turbine speed control system based on valve flow characteristics includes:

[0030] A combined valve position command obtaining unit, used to obtain a combined valve position command;

[0031] A throttle valve command determining unit, connected to the combined valve position command obtaining unit, used to determine the throttle valve command of any sequence valve according to the combined valve position command;

[0032] An opening adjustment unit, respectively connected to the throttle valve command determining unit and each sequence valve, used to adjust the opening of the corresponding sequence valve according to the throttle valve command of each sequence valve to adjust the speed of the steam turbine.

[0033] Optionally, the steam turbine speed control system based on valve flow characteristics further includes:

[0034] A total throttle valve command determining unit, connected to the throttle valve command determining unit, used to sum the throttle valve commands of each sequence valve to obtain a total throttle valve command;

[0035] A main steam flow determining unit, connected to the total throttle valve command determining unit, used to convert the total throttle valve command into a main steam flow using a first conversion coefficient. The first conversion coefficient is the conversion coefficient between the throttle valve command and the steam flow.

[0036] According to the specific embodiments provided by the present invention, the following technical effects are disclosed: First, the comprehensive valve position command is determined based on the simulation model and the operating data of the steam turbine; then, the valve control commands of each sequence valve are determined according to the comprehensive valve position command; finally, the opening degrees of the corresponding sequence valves are adjusted according to the valve control commands of each sequence valve to adjust the speed of the steam turbine. When performing the response curve simulation of the slip disturbance, it is closer to the actual link characteristics of the power plant, and a more real and accurate response process curve is obtained, reflecting the influence of the flow characteristics of the nonlinear link on the speed regulation of the steam turbine, improving the accuracy of the steam turbine speed regulation, and further improving the stability of the steam turbine. Description of the Drawings

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0038] Figure 1 It is a flowchart of the steam turbine speed regulation method based on the valve flow characteristics of the present invention;

[0039] Figure 2 It is a schematic structural diagram of the flow control module;

[0040] Figure 3 It is a schematic diagram of the process of converting the comprehensive valve position command into the valve control command of the sequence valve;

[0041] Figure 4 It is a schematic diagram of the process of obtaining the initial valve control command of the sequence valve according to the comprehensive valve control command;

[0042] Figure 5 It is a schematic diagram of the iterative calculation of the nth valve control command;

[0043] Figure 6 It is a schematic diagram of the improved low-frequency oscillation simulation model of the entire speed regulation system;

[0044] Figure 7 It is a schematic diagram of the presence of a slip signal within a certain period of time;

[0045] Figure 8 It is a schematic diagram of the load response curve;

[0046] Figure 9 It is a schematic diagram of the modules of the steam turbine speed regulation system based on the valve flow characteristics of the present invention.

[0047] Symbol Explanation:

[0048] Integrated valve position command acquisition unit - 1, governor valve command determination unit - 2, opening adjustment unit - 3, total governor valve command determination unit - 4, main steam flow determination unit - 5. Specific implementation manner

[0049] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0050] The purpose of the present invention is to provide a steam turbine speed regulation method and system based on valve flow characteristics. By converting the integrated valve position command into the governor valve command of each sequential valve, and then adjusting the opening of the sequential valve, the steam turbine is speed-regulated to improve the accuracy of speed regulation.

[0051] To make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific implementation manners.

[0052] Embodiment 1

[0053] This embodiment provides a steam turbine speed regulation method based on valve flow characteristics, and a speed regulation system is used to regulate the speed of the steam turbine. The speed regulation system includes 4 sequential valves.

[0054] As Figure 1 shown, the steam turbine speed regulation method based on valve flow characteristics provided in this embodiment includes:

[0055] S1: Obtain the integrated valve position command. Specifically, collect the current steam pressure, current speed, and current steam flow of the steam turbine. According to the current steam pressure, the current speed, and the current steam flow, use a PID controller to determine the integrated valve position command.

[0056] The present invention improves the sequential valve speed regulation part in the existing low-frequency oscillation simulation model of the speed regulation system. First, obtain the current operation data of the on-site speed regulation system of a certain 350MW thermal power unit and the control parameters of the speed regulation system model of a typical thermal power unit. Among them, the control parameters include the time constants of each control link (including the opening response time constant T C of the oil servo valve, the closing response time constant T D of the oil servo valve, and the position deviation response time constant T I ), the delay time T V of the mechanical components of each valve to act, and the current PID control parameters (including the proportional coefficient K P , the integral coefficient K Iand differential coefficient K D ) Then, based on the current operating data and control parameters, relevant parameters of the low-frequency oscillation simulation model of the speed control system are assigned to simulate the unit in the actual operating state. According to the control parameters of the typical thermal power unit speed control system, a valve flow module is constructed based on the actual valve flow characteristic curve of the unit. Since the power plant actually uses a four-control-valve unit, obvious inflection points will appear in the flow curves of the four sequential valves in each automatic operation interval. By dividing the operation interval of each sequential valve into four parts, a four-part flow control module is formed. The structure of the flow control module is as shown in Figure 2 , in which the four control-valve units correspond to the four sequential valves respectively. By executing step S2 through the flow control module, the steam flow control of the steam turbine is realized. The flow control module can effectively reflect the influence of the valve flow inflection point on power control and the influence of the closing of a single valve during the valve switching test on the valve flow characteristics.

[0057] S2: For any one of the sequential valves, determine the valve control instruction of the sequential valve according to the comprehensive valve position instruction.

[0058] In this embodiment, step S2 specifically includes:

[0059] S21: Convert the comprehensive valve position instruction into a comprehensive valve control instruction by using a second conversion coefficient. The second conversion coefficient is the conversion coefficient between the valve position instruction and the valve control instruction. That is, D CV = K2·P CV . Wherein, P CV is the comprehensive valve position instruction, K2 is the second conversion coefficient, and D CV is the comprehensive valve control instruction.

[0060] S22: Perform iterative calculation on the comprehensive valve control instruction by using the non-linear characteristic parameters of the sequential valve to obtain the initial valve control instruction of the sequential valve.

[0061] Specifically, according to the non-linear characteristic parameters of the sequential valve and the comprehensive valve control instruction, determine the first valve control instruction of the sequential valve. In this embodiment, the non-linear characteristic parameters of the sequential valve include a first constant, a second constant, and a third constant. Use the formula D CV1 ′ = C2·(D CV - C1) + C3 to determine the first valve control instruction of the sequential valve; wherein, D CV1 ′ is the first valve control instruction of the sequential valve, C1 is the first constant, C2 is the second constant, and C3 is the third constant. In addition, the non-linear characteristic parameters of the sequential valve also include a fourth constant C4. The non-linear characteristic parameters are used to represent the parameters required in the valve non-linear characteristic and are determined by the valve non-linear characteristic.

[0062] For the nth iteration, determine the (n + 1)th valve command of the sequence valve according to the non-linear characteristic parameters of the sequence valve, the combined throttle valve command, and the nth valve command of the sequence valve; 0 < n.

[0063] Judge whether n is equal to the iteration threshold. If so, the (n + 1)th valve command is the initial valve command of the sequence valve; otherwise, perform the (n + 1)th iteration.

[0064] Obtain the commands for the opening intervals of each sequence valve through iterative calculation.

[0065] As Figure 3 shown is the schematic diagram of the process of obtaining the initial valve command of the sequence valve according to the combined throttle valve command D CV D CV1 . As Figure 4 shown is the schematic diagram of iterative calculation.

[0066] S23: Determine the valve command of the sequence valve according to the combined throttle valve command, the opening threshold of the sequence valve, and the initial valve command of the sequence valve.

[0067] Specifically, judge whether the combined throttle valve command is less than or equal to the opening threshold of the sequence valve. If so, determine the valve command of the sequence valve according to the initial valve command of the sequence valve by using the first function; otherwise, determine the valve command of the sequence valve according to the initial valve command of the sequence valve by using the second function. Among them, the first function and the second function are pre-determined functions that enable the valve command of the sequence valve to be within the non-linear interval of the sequence valve, representing the valve opening control of the classical electro-hydraulic servo system plus the calculation considering the non-linear characteristic of the valve flow. That is, the valve commands satisfying the non-linear interval of the sequence valve are given by the first function and the second function, and the formula is:

[0068]

[0069] Among them, D CV1 is the initial valve command of the sequence valve, G1() is the first function, G2() is the second function, D CVa is the opening threshold of the sequence valve, and the opening thresholds of each sequence valve are different.

[0070] For a better understanding of the solution of the present invention, as Figure 5 shown, taking the first sequence valve as an example, the combined valve position command is converted into the initial valve command D CV1 of the first sequence valve through the combined valve position command module, and then enters the valve position PID control and valve adjustment link. On the other hand, the valve command passes through the flow non-linear characteristic interval determination link to determine the valve command D GV1 of the first sequence valve.

[0071] S3: Adjust the opening degree of the corresponding sequence valve according to the valve control instructions of each sequence valve to regulate the speed of the steam turbine.

[0072] Further, the steam turbine speed regulation method based on the valve flow characteristics further includes:

[0073] S4: Sum up the valve control instructions of each sequence valve to obtain the total valve control instruction. That is, D GV = D GV1 + D GV2 + D GV3 + D GV4 . Wherein, D GV is the total valve control instruction, D GV1 is the valve control instruction of the first sequence valve, D GV2 is the valve control instruction of the second sequence valve, D GV3 is the valve control instruction of the third sequence valve, D GV4 is the valve control instruction of the fourth sequence valve.

[0074] S5: Use the first conversion coefficient to convert the total valve control instruction into the main steam flow rate. The first conversion coefficient is the conversion coefficient between the valve control instruction and the steam flow rate. That is, P GV = K1·D GV . Wherein, P GV is the main steam flow rate, and K1 is the first conversion coefficient.

[0075] The present invention takes into account that in the actual control of power plants, for the four-valve control units of power plants, in order to improve the operating economy of the units, the sequence valve operation mode is usually adopted, that is, the four control valves are opened in sequence. There are obvious inflection points in the flow characteristic curves of the sequence valves, and there is a non-linear relationship between the valve opening degree and the steam flow rate. The typical speed regulation system model cannot reflect this characteristic. Therefore, the present invention adds a flow control module to the typical speed regulation system model. The speed regulation model after introducing the flow control module can be closer to the actual link characteristics of the power plant when simulating the response curve of the slip disturbance, obtain a more real and accurate response process curve, reflect the influence of the flow characteristics of the non-linear link on the control ability, and be more targeted and practical when designing the control strategy based on the simulation results. The improved low-frequency oscillation simulation model of the entire speed regulation system of the present invention is as Figure 6 shown, and the inputs are the current steam pressure P M1 of the steam turbine, the current speed Δω and the current steam flow rate P E . Based on the improved low-frequency oscillation simulation model of the entire speed regulation system, the oscillation curve of the system is obtained through the simulation analysis method, and the control strategy is formulated based on this to ensure the stability of the system speed regulation.

[0076] To better understand the solution of the present invention, the following uses the actual low-frequency oscillation data of the unit to verify the low-frequency oscillation simulation model of the entire speed regulation system improved by the present invention. A signal is given to indicate the existence of a slip signal within a certain period of time, such as Figure 7 as shown.

[0077] This signal is respectively applied to the original classical model and the low-frequency oscillation model with small frequency difference compensation and flow control module added. The sampling time is set to 0.02 s, and the load response curves corresponding from 0 s to 600 s are recorded. The part that can obviously show the curve difference is intercepted as Figure 8 as shown.

[0078] It can be seen that after introducing the flow control module, the simulation curve of the model can obviously represent the dynamic characteristics of the oscillation curve. In contrast, the typical speed regulation model ignores the actual characteristics of the valve flow and cannot reflect the deterioration characteristics of the frequency modulation quality caused by the non-linearity of the valve adjustment, which in turn leads to a large difference between the simulation results of the typical model and the actual power curve, indicating that the simulation results of the improved model can better reflect the influence of the actual non-linearity of the valve on the control quality and system oscillation.

[0079] Embodiment 2

[0080] In order to execute the method corresponding to the above Embodiment 1 to achieve the corresponding functions and technical effects, the following provides a steam turbine speed regulation system based on the valve flow characteristics.

[0081] As Figure 9 shown, the steam turbine speed regulation system based on the valve flow characteristics provided in this embodiment includes: a comprehensive valve position command acquisition unit 1, a throttle valve command determination unit 2, and an opening adjustment unit 3.

[0082] Among them, the comprehensive valve position command acquisition unit 1 is used to acquire the comprehensive valve position command.

[0083] The throttle valve command determination unit 2 is connected to the comprehensive valve position command acquisition unit 1. The throttle valve command determination unit 2 is used to determine the throttle valve command of any sequence valve according to the comprehensive valve position command.

[0084] The opening adjustment unit 3 is respectively connected to the throttle valve command determination unit 2 and each sequence valve. The opening adjustment unit 3 is used to adjust the opening of the corresponding sequence valve according to the throttle valve command of each sequence valve to regulate the speed of the steam turbine.

[0085] Furthermore, the steam turbine speed regulation system based on the valve flow characteristics further includes: a total throttle valve command determination unit 4 and a main steam flow determination unit 5.

[0086] The total governing valve command determination unit 4 is connected to the governing valve command determination unit 2. The total governing valve command determination unit 4 is used to sum up the governing valve commands of each sequence valve to obtain the total governing valve command.

[0087] The main steam flow rate determination unit 5 is connected to the total governing valve command determination unit 4. The main steam flow rate determination unit 5 is used to convert the total governing valve command into the main steam flow rate by using a first conversion coefficient; the first conversion coefficient is the conversion coefficient between the governing valve command and the steam flow rate.

[0088] Compared with the prior art, the beneficial effects of the steam turbine governing system based on the valve flow characteristics provided in this embodiment are the same as those of the steam turbine governing method based on the valve flow characteristics provided in Embodiment 1, and will not be elaborated here.

[0089] In this specification, each embodiment is described in a progressive manner. The key point of each embodiment is the difference from other embodiments. The same or similar parts among the embodiments can be referred to each other.

[0090] In this article, specific examples are used to elaborate the principles and implementation manners of the present invention. The descriptions of the above embodiments are only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A steam turbine speed regulation method based on the flow characteristics of valves, which uses a speed regulation system to regulate the speed of the steam turbine. The speed regulation system includes 4 sequence valves, and is characterized in that, The steam turbine speed regulation method based on the valve flow characteristics includes: Obtaining a comprehensive valve position command; For any one of the sequence valves, determining the valve position command of the sequence valve according to the comprehensive valve position command; Adjusting the opening of the corresponding sequence valve according to the valve position commands of each sequence valve to regulate the speed of the steam turbine; Summing up the valve position commands of each sequence valve to obtain a total valve position command; Converting the total valve position command into the main steam flow rate by using a first conversion coefficient; the first conversion coefficient is the conversion coefficient between the valve position command and the steam flow rate; Among them, determining the valve position command of the sequence valve according to the comprehensive valve position command specifically includes: Converting the comprehensive valve position command into a comprehensive valve position command by using a second conversion coefficient; the second conversion coefficient is the conversion coefficient between the valve position command and the valve position command; Using the non - linear characteristic parameters of the said sequence valve, perform iterative calculation on the said comprehensive throttle valve command to obtain the initial throttle valve command of the said sequence valve, specifically including: determining the first throttle valve command of the said sequence valve according to the non - linear characteristic parameters of the said sequence valve and the said comprehensive throttle valve command; for the n - th iteration, determining the (n + 1) - th throttle valve command of the said sequence valve according to the non - linear characteristic parameters of the said sequence valve, the said comprehensive throttle valve command and the n - th throttle valve command of the said sequence valve; 0 < n; judging whether n is equal to the iteration threshold, if so, the (n + 1) - th throttle valve command is the initial throttle valve command of the said sequence valve, otherwise perform the (n + 1) - th iteration; the non - linear characteristic parameters of the said sequence valve include a first constant, a second constant and a third constant; using the formula D CV1 ′ = C2·(D CV - C1)+C3 to determine the first throttle valve command of the said sequence valve; where, C1 is the first constant, C2 is the second constant, C3 is the third constant, D CV is the comprehensive throttle valve command, D CV1 ′ is the first throttle valve command of the sequence valve; Determining the valve position command of the sequence valve according to the comprehensive valve position command, the opening threshold of the sequence valve and the initial valve position command of the sequence valve.

2. The steam turbine speed regulation method based on the valve flow characteristics according to claim 1, wherein Determining the valve position command of the sequence valve according to the comprehensive valve position command, the opening threshold of the sequence valve and the initial valve position command of the sequence valve specifically includes: Judging whether the comprehensive valve position command is less than or equal to the opening threshold of the sequence valve. If so, determining the valve position command of the sequence valve according to the initial valve position command of the sequence valve by using a first function; otherwise, determining the valve position command of the sequence valve according to the initial valve position command of the sequence valve by using a second function; the first function and the second function are functions determined in advance to make the valve position command of the sequence valve in the non-linear interval of the sequence valve.

3. The steam turbine speed regulation method based on the valve flow characteristics according to claim 1, wherein, The obtaining of the comprehensive valve position command specifically includes: Collecting the current steam pressure, current speed and current steam flow rate of the steam turbine; Determining the comprehensive valve position command by using a PID controller according to the current steam pressure, the current speed and the current steam flow rate.

4. A steam turbine governing system based on valve flow characteristics, adopting the steam turbine governing method based on valve flow characteristics as described in Claim 1, the steam turbine governing system based on valve flow characteristics is connected to the governing system of the steam turbine, the governing system includes 4 sequence valves, and is characterized in that, The steam turbine speed regulation system based on the valve flow characteristics includes: A comprehensive valve position command acquisition unit for obtaining a comprehensive valve position command; A valve position command determination unit connected to the comprehensive valve position command acquisition unit for determining the valve position command of any one of the sequence valves according to the comprehensive valve position command; An opening adjustment unit respectively connected to the valve position command determination unit and each sequence valve for adjusting the opening of the corresponding sequence valve according to the valve position commands of each sequence valve to regulate the speed of the steam turbine.

5. The steam turbine governing system based on the valve flow characteristics according to claim 4, characterized in that, The steam turbine speed regulation system based on the valve flow characteristics further includes: A total valve position command determination unit connected to the valve position command determination unit for summing up the valve position commands of each sequence valve to obtain a total valve position command; A main steam flow rate determination unit connected to the total valve position command determination unit for converting the total valve position command into the main steam flow rate by using a first conversion coefficient; the first conversion coefficient is the conversion coefficient between the valve position command and the steam flow rate.

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