Steam turbine control method and related device

Abstract

The invention discloses a steam turbine control method and a related device, and relates to the field of steam turbines.The steam turbine control method comprises the steps that the actual rotating speed of a steam turbine is obtained, and under the condition that the actual rotating speed of the steam turbine is larger than a first steam turbine super-acceleration protection logic effective rotating speed threshold value; and the steam turbine is controlled to input steam turbine super-acceleration protection logic when the steam turbine generator unit is in the non-grid-connected operation state so as to restrain the steam turbine from rapidly increasing the speed under the load shedding working condition, and input of the steam turbine super-acceleration protection logic is forbidden when the steam turbine generator unit is in the grid-connected operation state. The grid-connected locking condition is added in the turbine super-acceleration protection logic, when the turbine generator unit is in the non-grid-connected working condition, the turbine super-acceleration protection logic is input, and overspeed trip caused by the fact that the rotation speed acceleration of the turbine is too large is avoided; when the steam turbine generator unit is in a grid-connected working condition, steam turbine super-acceleration protection logic is not input, frequent action of a steam turbine regulating valve is avoided, and power grid safety and nuclear safety are guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of steam turbines, and more specifically, to a steam turbine control method and related devices. Background Art

[0002] When the steam turbine generator unit is in grid-connected or off-grid operation, when the steam turbine speed exceeds the steam turbine speed threshold and the steam turbine speed rapidly rises and exceeds the acceleration threshold, the steam turbine super-acceleration protection logic is executed. Specifically: close the high-pressure control valves and intermediate-pressure control valves of the steam turbine to reduce the steam turbine speed and prevent the steam turbine speed from exceeding the unit trip speed.

[0003] However, in the grid-connected condition of the steam turbine generator unit, when the steam turbine super-acceleration protection logic is executed, due to the inconsistent response of the steam turbine control valve action and the power grid frequency regulation, it will cause disturbances to the power grid, and even cause a large oscillation of the power grid frequency and make the power grid unstable, thus endangering the power grid safety; at the same time, when the steam turbine super-acceleration protection logic is restored, after the steam turbine control valve is quickly opened, due to the untimely closing of the steam turbine bypass discharge system, the pressure of the nuclear island steam generator of the nuclear power steam turbine will rapidly decrease, triggering an automatic shutdown of the nuclear island, thus endangering nuclear safety. In other words, the more times the steam turbine super-acceleration protection logic triggers the frequent action of the steam turbine control valve, the greater the impact on the power grid safety and nuclear safety.

[0004] Therefore, how to provide a steam turbine control method to effectively reduce the impact of the steam turbine super-acceleration protection logic on the power grid safety and nuclear safety has become an urgent technical problem to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the present invention discloses a steam turbine control method and related devices to effectively reduce the impact of the steam turbine super-acceleration protection logic on the power grid safety and nuclear safety.

[0006] A steam turbine control method includes:

[0007] Obtain the actual speed of the steam turbine;

[0008] Judge whether the actual speed of the steam turbine is greater than the first steam turbine super-acceleration protection logic activation speed threshold;

[0009] If so, control the steam turbine to activate the steam turbine super-acceleration protection logic when the steam turbine generator unit is in off-grid operation state to suppress the rapid speed increase of the steam turbine under load rejection conditions, and prohibit the activation of the steam turbine super-acceleration protection logic when the steam turbine generator unit is in grid-connected operation state.

[0010] Optionally, it further includes:

[0011] If the actual speed of the steam turbine is not greater than the effective speed threshold of the first steam turbine overspeed acceleration protection logic, both the steam turbine overspeed acceleration protection logic and the steam turbine overspeed protection logic are prohibited from being put into operation.

[0012] Optionally, when the steam turbine generator set is in a non-grid-connected operation state, the steam turbine overspeed acceleration protection logic is put into operation to suppress the rapid speed increase of the steam turbine under the load rejection condition, and when the steam turbine generator set is in a grid-connected operation state, the steam turbine overspeed acceleration protection logic is prohibited from being put into operation, including:

[0013] If the actual speed of the steam turbine is greater than the effective speed threshold of the first steam turbine overspeed acceleration protection logic and not greater than the effective speed threshold of the second steam turbine overspeed acceleration protection logic, the steam turbine speed acceleration is obtained.

[0014] If the steam turbine speed acceleration is not greater than the steam turbine speed acceleration threshold, it is judged whether the steam turbine generator set is in a grid-connected operation state.

[0015] If not, when the steam turbine generator set is in a non-grid-connected operation state, the steam turbine overspeed acceleration protection logic is put into operation for the steam turbine, and the steam turbine overspeed acceleration protection does not act.

[0016] If so, when the steam turbine generator set is in a grid-connected operation state, the steam turbine overspeed acceleration protection logic is prohibited from being put into operation for the steam turbine.

[0017] Optionally, when the steam turbine generator set is in a non-grid-connected operation state, the steam turbine overspeed acceleration protection logic is put into operation to suppress the rapid speed increase of the steam turbine under the load rejection condition, and when the steam turbine generator set is in a grid-connected operation state, the steam turbine overspeed acceleration protection logic is prohibited from being put into operation, including:

[0018] If the actual speed of the steam turbine is greater than the effective speed threshold of the first steam turbine overspeed acceleration protection logic and not greater than the effective speed threshold of the second steam turbine overspeed acceleration protection logic, the steam turbine speed acceleration is obtained.

[0019] If the steam turbine speed acceleration is greater than the steam turbine speed acceleration threshold, the effective steam demand parameter protection component is set to a set value, and it is judged whether the steam turbine generator set is in a grid-connected operation state.

[0020] If not, when the steam turbine generator set is in a non-grid-connected operation state, the steam turbine overspeed acceleration protection logic is put into operation for the steam turbine, and the steam turbine overspeed acceleration protection is controlled to act, and all the admission control valves of the steam turbine governing system are controlled to close to cut off the steam supply to the steam turbine; when the steam turbine speed acceleration is reduced to less than the steam turbine speed acceleration threshold, the opening of the admission control valve is closed-loop controlled according to the steam turbine output power.

[0021] If so, when the steam turbine is in the grid-connected operation state of the steam turbine generator set, prohibit the input of the steam turbine over-acceleration protection logic, keep the total effective steam demand of the steam turbine unchanged, and control the steam turbine regulating valve not to act.

[0022] Optionally, the control of the steam turbine to input the steam turbine over-acceleration protection logic when the steam turbine generator set is in the off-grid operation state to suppress the rapid speed increase of the steam turbine under the load rejection condition, and the prohibition of inputting the steam turbine over-acceleration protection logic when the steam turbine generator set is in the grid-connected operation state includes:

[0023] If the actual speed of the steam turbine is greater than the second steam turbine over-acceleration protection logic activation speed threshold and not greater than the first steam turbine overspeed protection logic activation speed threshold, obtain the steam turbine speed acceleration, where the second steam turbine over-acceleration protection logic activation speed threshold is greater than the first steam turbine over-acceleration protection logic activation speed threshold;

[0024] If the steam turbine speed acceleration is not greater than the steam turbine speed acceleration threshold, determine whether the steam turbine generator set is in the grid-connected operation state;

[0025] If not, when the steam turbine generator set is in the off-grid operation state, control the steam turbine to input the steam turbine over-acceleration protection logic, and the steam turbine over-acceleration protection does not act;

[0026] If so, when the steam turbine generator set is in the grid-connected operation state, control the steam turbine to prohibit the input of the steam turbine over-acceleration protection logic;

[0027] If the steam turbine speed acceleration is greater than the steam turbine speed acceleration threshold and the duration of the steam turbine speed acceleration being greater than the steam turbine speed acceleration threshold is less than the first preset time period, determine whether the steam turbine generator set is in the grid-connected operation state;

[0028] If not, when the steam turbine generator set is in the off-grid operation state, control the steam turbine to input the steam turbine over-acceleration protection logic, and the steam turbine over-acceleration protection acts;

[0029] If so, when the steam turbine generator set is in the grid-connected operation state, control the steam turbine to prohibit the input of the steam turbine over-acceleration protection logic.

[0030] Optionally, the control of the steam turbine to input the steam turbine over-acceleration protection logic when the steam turbine generator set is in the off-grid operation state to suppress the rapid speed increase of the steam turbine under the load rejection condition, and the prohibition of inputting the steam turbine over-acceleration protection logic when the steam turbine generator set is in the grid-connected operation state includes:

[0031] If the actual speed of the steam turbine is greater than the second steam turbine over-acceleration protection logic activation speed threshold and not greater than the first steam turbine over-speed protection logic activation speed threshold, obtain the steam turbine speed acceleration, where the second steam turbine over-acceleration protection logic activation speed threshold is greater than the first steam turbine over-acceleration protection logic activation speed threshold;

[0032] If the steam turbine speed acceleration is greater than the steam turbine speed acceleration threshold and lasts for the first preset time period, set the protection component of the effective steam demand parameter to a set value and determine whether the steam turbine generator set is in a grid-connected operation state;

[0033] If not, when the steam turbine generator set is in a non-grid-connected operation state, control the steam turbine to activate the steam turbine over-acceleration protection logic, control the steam turbine over-acceleration protection to act, control all the admission control valves of the steam turbine regulating system to close, and cut off the steam admission to the steam turbine; when the time for cutting off the steam admission to the steam turbine reaches the second preset time period and the steam turbine speed acceleration drops to less than the steam turbine speed acceleration threshold, perform closed-loop control on the opening of the admission control valve according to the output power of the steam turbine;

[0034] If so, prohibit activating the steam turbine over-acceleration protection logic, control the value of the protection component of the effective steam demand parameter to remain unchanged, and keep the opening of the admission control valve unchanged.

[0035] Optionally, the control to activate the steam turbine over-acceleration protection logic when the steam turbine generator set is in a non-grid-connected operation state to suppress the rapid speed increase of the steam turbine under the load rejection condition and prohibit activating the steam turbine over-acceleration protection logic when the steam turbine generator set is in a grid-connected operation state includes:

[0036] When the actual speed of the steam turbine is greater than the first steam turbine over-speed protection logic activation speed threshold and not greater than the second steam turbine over-speed protection logic activation speed threshold, set the protection component of the effective steam demand parameter to a set value and determine whether the steam turbine generator set is in a grid-connected operation state, where the second steam turbine over-speed protection logic activation speed threshold is greater than the first steam turbine over-speed protection logic activation speed threshold;

[0037] If not, when the steam turbine speed acceleration is not greater than the steam turbine speed acceleration threshold, control the effective steam demand parameter and the admission control valve to remain unchanged; when the steam turbine speed acceleration is greater than the steam turbine speed acceleration threshold, control the steam turbine over-acceleration protection to act. If the time when the steam turbine speed acceleration is greater than the steam turbine speed acceleration threshold lasts for the first preset time period, control the maintenance time of the steam turbine over-acceleration protection action to reach the second preset time period;

[0038] If so, prohibit the input of the steam turbine super-acceleration protection logic and input the steam turbine overspeed protection logic. By outputting the difference between the total effective steam demand parameter and the protection component of the effective steam demand parameter, control all the admission control valves of the steam turbine regulating system to close and cut off the steam supply to the steam turbine. When the rotational speed acceleration of the steam turbine decreases to less than the first steam turbine overspeed protection logic activation speed threshold, perform closed-loop control on the opening of the admission control valve according to the output power of the steam turbine.

[0039] Optionally, when the steam turbine generator set is in a non-parallel operation state, input the steam turbine super-acceleration protection logic to suppress the rapid speed increase of the steam turbine under the load rejection condition, and when the steam turbine generator set is in a parallel operation state, prohibit the input of the steam turbine super-acceleration protection logic, including:

[0040] When the actual rotational speed of the steam turbine is greater than the second steam turbine overspeed protection logic activation speed threshold, set the protection component of the effective steam demand parameter to a set value and determine whether the steam turbine generator set is in a parallel operation state;

[0041] If not, control the input of the steam turbine super-acceleration protection logic and the steam turbine overspeed protection logic, and the steam turbine overspeed protection takes precedence over the steam turbine super-acceleration protection. By outputting the difference between the total effective steam demand parameter and the protection component of the effective steam demand parameter, control all the admission control valves of the steam turbine regulating system to close and cut off the steam supply to the steam turbine. When the rotational speed of the steam turbine decreases to less than the second steam turbine overspeed protection logic activation speed threshold, perform closed-loop control on the opening of the admission control valve according to the output power of the steam turbine;

[0042] If so, prohibit the input of the steam turbine super-acceleration protection logic and input the steam turbine overspeed protection logic. By outputting the difference between the total effective steam demand parameter and the protection component of the effective steam demand parameter, control all the admission control valves of the steam turbine regulating system to close and cut off the steam supply to the steam turbine. When the rotational speed of the steam turbine decreases to less than the first steam turbine overspeed protection logic activation speed threshold, perform closed-loop control on the opening of the admission control valve according to the output power of the steam turbine.

[0043] A steam turbine control device includes:

[0044] A rotational speed acquisition unit for acquiring the actual rotational speed of the steam turbine;

[0045] A judgment unit for judging whether the actual rotational speed of the steam turbine is greater than the first steam turbine super-acceleration protection logic activation speed threshold;

[0046] A control unit, configured to, when the determination unit determines as yes, control the steam turbine to activate the steam turbine over-acceleration protection logic when the steam turbine generator set is in a non-grid-connected operation state, so as to inhibit the rapid speed increase of the steam turbine under the load rejection condition, and prohibit the activation of the steam turbine over-acceleration protection logic when the steam turbine generator set is in a grid-connected operation state.

[0047] A computer storage medium storing at least one instruction, where the at least one instruction, when executed by a processor, implements any steam turbine control method.

[0048] An electronic device including: a memory and a processor;

[0049] The memory is used to store at least one instruction;

[0050] The processor is configured to execute the at least one instruction to implement any steam turbine control method.

[0051] As can be seen from the above technical solutions, the present invention discloses a steam turbine control method and related devices. The actual speed of the steam turbine is obtained. When the actual speed of the steam turbine is greater than the first steam turbine over-acceleration protection logic activation speed threshold, the steam turbine is controlled to activate the steam turbine over-acceleration protection logic when the steam turbine generator set is in a non-grid-connected operation state, so as to inhibit the rapid speed increase of the steam turbine under the load rejection condition, and prohibit the activation of the steam turbine over-acceleration protection logic when the steam turbine generator set is in a grid-connected operation state. The present invention adds a grid-connected locking condition to the steam turbine over-acceleration protection logic, that is, adds a determination condition for whether the steam turbine generator set is grid-connected or non-grid-connected with the power grid. When the steam turbine generator set is in a non-grid-connected condition, by activating the steam turbine over-acceleration protection logic, the rapid speed increase of the steam turbine under the load rejection condition is inhibited, the control of the steam turbine speed is realized, and the overspeed trip of the steam turbine due to excessive acceleration of the steam turbine speed is avoided; and when the steam turbine generator set is in a grid-connected condition, the steam turbine over-acceleration protection logic is not activated to avoid frequent operation of the steam turbine regulating valve and ensure the safety of the power grid and nuclear safety. Description of the Drawings

[0052] 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 the description of the embodiments or the prior art. Obviously, the following drawings are only the embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained according to the disclosed drawings without creative efforts.

[0053] Figure 1 It is a flowchart of a steam turbine control method disclosed in an embodiment of the present invention;

[0054] Figure 2Schematic diagram of the structure of a steam turbine control device disclosed in an embodiment of the present invention;

[0055] Figure 3 Schematic diagram of the structure of an electronic device disclosed in an embodiment of the present invention. Detailed implementation manners

[0056] 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 of 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.

[0057] When the steam turbine engine is in grid-connected operation, in working conditions such as a fault near the outlet of the high-voltage bus and bipolar blocking of a UHV large direct current, the steam turbine over-acceleration protection logic is to protect the steam turbine speed from exceeding 110% of the turbine trip speed, and the speed is controlled by closing the steam turbine regulating valve; however, due to the overly conservative setting of the steam turbine over-acceleration protection logic, the steam turbine regulating valve frequently switches in the above-mentioned working conditions, causing disturbances to the power grid. In severe working conditions, it even leads to power grid instability; in addition, during the frequent switching of the steam turbine regulating valve, there will also be nuclear power unit steam generator water level protection actions or pressure protection actions caused by the untimely coordination of the opening and closing of the regulating valve and the bypass discharge valve, resulting in the risk of turbine shutdown and reactor shutdown, which is not conducive to nuclear safety. The original intention of the steam turbine over-acceleration protection logic design is to protect the unit, but in fact, it cannot fully play the role of protecting the unit, but instead leads to power grid safety risks and nuclear safety risks.

[0058] Based on this, the embodiments of the present invention disclose a steam turbine control method and related device, which obtain the actual speed of the steam turbine. When the actual speed of the steam turbine is greater than the first steam turbine over-acceleration protection logic activation speed threshold, the steam turbine over-acceleration protection logic is controlled to be activated when the steam turbine generator set is in a non-grid-connected operation state to suppress the rapid speed increase of the steam turbine under the load rejection condition, and the steam turbine over-acceleration protection logic is prohibited from being activated when the steam turbine generator set is in a grid-connected operation state. The present invention adds a grid connection locking condition to the steam turbine over-acceleration protection logic, that is, adds a determination condition for the grid connection and non-grid connection between the steam turbine generator set and the power grid. When the steam turbine generator set is in a non-grid-connected working condition, by activating the steam turbine over-acceleration protection logic, the rapid speed increase of the steam turbine under the load rejection condition is suppressed, the control of the steam turbine speed is realized, and the overspeed trip caused by excessive acceleration of the steam turbine speed is avoided; and when the steam turbine generator set is in a grid-connected working condition, the steam turbine over-acceleration protection logic is not activated to avoid frequent actions of the steam turbine regulating valve and ensure power grid safety and nuclear safety.

[0059] For ease of understanding, the thresholds involved in the steam turbine control method disclosed in the present invention are described below as follows:

[0060] The thresholds involved in this application mainly include: A (the effective speed threshold of the first steam turbine over-acceleration protection logic), B (the effective speed threshold of the second steam turbine over-acceleration protection logic), C (the effective speed threshold of the first steam turbine overspeed protection logic), D (the effective speed threshold of the second steam turbine overspeed protection logic), and X (the steam turbine speed acceleration threshold).

[0061] The value-taking basis for each threshold is as follows:

[0062] (1) The effective speed threshold of the first steam turbine over-acceleration protection logic, denoted as A.

[0063] When the steam turbine speed reaches B, and the steam turbine speed acceleration reaches X and maintains for a preset time period (such as 0.1 s) or more, to avoid frequent operation of the steam turbine over-acceleration protection, the steam turbine over-acceleration protection logic setting should ensure that it is triggered when the actual steam turbine speed is greater than A and not greater than B, and not triggered when the actual speed is greater than B and not greater than C. In other words, when the steam turbine speed acceleration maintains the preset time period (such as 0.1 s), the speed should not reach B. Therefore, the value of A should be less than (B - X×0.1 s).

[0064] Based on this, the value of A is preferably 100.4% of the rated steam turbine speed.

[0065] (2) The effective speed threshold of the second steam turbine over-acceleration protection logic, denoted as B.

[0066] The steam turbine over-acceleration protection logic is only enabled under the condition that the steam turbine generator set is disconnected from the power grid (i.e., the steam turbine generator set is in a non-parallel operation state). At this time, the effective speed threshold of the steam turbine overspeed protection logic is D. Therefore, when the steam turbine speed reaches B and the speed acceleration reaches X and lasts for a preset time period (such as 0.1 s), the steam turbine over-acceleration protection logic will act. To ensure that after the steam turbine acts under the condition that the actual steam turbine speed is greater than B and not greater than D, it will not trigger when the actual steam turbine speed is greater than D, in this application, the value of B is set to D minus the speed increase value of the steam turbine when the steam turbine acceleration is X.

[0067] Since the value of X is usually the acceleration value under the condition that the steam turbine suddenly loses 50% of its rated load, in order to ensure that when the steam turbine loses more than 50% of its rated load, the steam turbine speed does not reach D, the acceleration value can be taken as 2X during the calculation process. Therefore, the value of the speed rise is equal to the steam turbine speed acceleration 2X multiplied by the acceleration maintenance time t. The acceleration maintenance time t is equal to the logic set maintenance time, plus the system delay time, plus the average oil valve stroke closing time of the steam turbine, plus the cylinder volume time. Based on these calculations, the value of B can be obtained.

[0068] Based on this, the value of B is preferably 101.1% of the rated speed of the steam turbine.

[0069] (3)The effective speed threshold of the first steam turbine overspeed protection logic is represented by C.

[0070] Under the grid-connected condition of the steam turbine generator set, the effective speed threshold of the steam turbine overspeed protection logic is adjusted from D to C, and there is no acceleration protection criterion. Therefore, C should be able to ensure that under a large acceleration (exceeding X), the closing of the steam turbine governing valve can ensure that the steam turbine speed does not exceed 110% of the overspeed protection trip value (if the steam turbine speed exceeds this value, excessive centrifugal stress will cause damage to important equipment such as the fracture of the steam turbine rotor blades and the breakage of the rotor shaft). This process is actually to calculate the maximum flying-up speed of the steam turbine under the condition of suddenly losing the rated load at different initial speeds.

[0071] To ensure that the calculation is as conservative and accurate as possible, in actual applications, the maximum flying-up speed of the steam turbine when suddenly losing no-load during the commissioning of the steam turbine generator set can be adopted, and the contribution of the abnormal condition of the extraction steam check valve to the flying-up speed of the steam turbine speed can be superimposed (conservatively taking the energy generated by the abnormal extraction steam check valve as 1.4 times the energy during normal no-load rejection).

[0072] According to the commissioning test data and based on the law of conservation of energy, calculate the maximum flying-up speed of the steam turbine at different initial speeds, and take the initial speed of the steam turbine when the maximum flying-up speed under the abnormal condition of the extraction steam check valve does not exceed 110% as the maximum value of C. At the same time, to ensure that the steam turbine regulating valve has as few action times as possible, the value of C, that is, the value calculated according to the law of conservation of energy as mentioned above.

[0073] Based on this, the value of C is preferably 103% of the rated speed of the steam turbine.

[0074] (4)The effective speed threshold of the second steam turbine overspeed protection logic is represented by D.

[0075] Considering that the overspeed trip protection setting value of the steam turbine is generally set to 110% of the rated speed of the steam turbine, the value of the effective speed threshold D of the second steam turbine overspeed protection logic should be ensured so that when the steam turbine speed reaches the D value but the acceleration does not exceed the steam turbine speed acceleration threshold X, the steam turbine speed increase will not cause an overspeed trip (otherwise the steam turbine super-acceleration protection logic will be engaged).

[0076] Then D = 110% of the rated speed of the steam turbine - the speed increase of the steam turbine. The speed increase of the steam turbine can be estimated by multiplying the steam turbine speed acceleration threshold X by the sum of the system delay time, the average closing time of the steam turbine servo valve, and the cylinder volume time.

[0077] Based on this, the preferred value of D is 107% of the rated speed of the steam turbine.

[0078] (5) The steam turbine speed acceleration threshold, denoted by X.

[0079] To ensure that the steam turbine speed can be quickly stabilized under the condition of the steam turbine load rejection and to avoid overspeed tripping due to excessive steam turbine speed acceleration, generally in engineering, the acceleration when the steam turbine rejects 50% of the rated load from the rated load is taken as the effective threshold of the speed acceleration for the super-acceleration protection. The specific calculation method is as follows:

[0080] A) Calculate the inertia time constant T of the steam turbine-generator unit according to the moment of inertia of the steam turbine, the rated speed, and the rated capacity of the generator;

[0081] B) According to the inertia time constant, from T = 60n / a (where n is the rated speed of the steam turbine), calculate the speed acceleration a of the steam turbine when rejecting the load from the rated load to the no-load state;

[0082] C) According to (where is the load rejection amount of the unit from the rated power load platform, is the load rejection amount of the steam turbine-generator unit from the rated load to the no-load state), calculate the steam turbine speed acceleration when the steam turbine rejects 50% of the load from the rated load as X.

[0083] Based on this, the preferred value of X is 66 rpm / s.

[0084] See Figure 1, A flow chart of a steam turbine control method disclosed in an embodiment of the present invention. This method is applied to GRE (Governor and Regulating Equipment, steam turbine regulating system). The GER realizes closed-loop control of parameters such as unit power, frequency, and pressure by adjusting the opening of the steam inlet valve of the steam turbine, and ensures that the equipment is free from thermal stress and mechanical damage. The core modules of this system include an electronic control cabinet, a human-machine interface (operator station, engineer station), and an actuator (such as a high-pressure / low-pressure regulating valve), etc. Among them, the electronic control cabinet includes: DPU (Data Processing Unit, data processing unit) and I / O cards.

[0085] The steam turbine control method includes:

[0086] Step S101, obtain the actual speed of the steam turbine.

[0087] In practical applications, the actual speed of the steam turbine can be obtained through sensors, such as magnetoelectric speed sensors, Hall effect sensors, etc.

[0088] Step S102, determine whether the actual speed of the steam turbine is greater than the first steam turbine over-acceleration protection logic activation speed threshold. If so, execute step S103.

[0089] Generally, when the steam turbine generator set is in grid-connected or off-grid operation, when the steam turbine speed exceeds the steam turbine speed threshold and the steam turbine speed rises rapidly beyond the acceleration threshold, the steam turbine over-acceleration protection logic is executed to reduce the steam turbine speed to avoid the steam turbine speed exceeding the unit trip speed.

[0090] The first steam turbine over-acceleration protection logic activation speed threshold A can be used as the minimum limit for determining whether the steam turbine over-acceleration protection logic is enabled. When the actual speed of the steam turbine is not greater than the first steam turbine over-acceleration protection logic activation speed threshold, it indicates that there will be no situation where the steam turbine speed exceeds the steam turbine speed threshold and the steam turbine speed rises rapidly beyond the acceleration threshold, and thus there will be no situation where the steam turbine speed exceeds the unit trip speed. At this time, control the steam turbine over-acceleration protection logic to be prohibited from being enabled. At the same time, it is also necessary to control the steam turbine over-speed protection logic to be prohibited from being enabled.

[0091] On the contrary, when the actual speed of the steam turbine is greater than the first steam turbine over-acceleration protection logic activation speed threshold, in order to avoid the steam turbine speed exceeding the unit trip speed, it is necessary to further determine whether to enable the steam turbine over-acceleration protection logic.

[0092] It should be noted that in practical applications, first, the turbine overspeed acceleration protection logic needs to be enabled, and then it is further determined whether to execute the turbine overspeed acceleration protection logic, that is, whether the turbine overspeed acceleration protection operates.

[0093] Step S103: When the steam turbine generator set is in a non-grid-connected operation state, enable the turbine overspeed acceleration protection logic to inhibit the rapid speed increase of the steam turbine under the load rejection condition, and when the steam turbine generator set is in a grid-connected operation state, prohibit enabling the turbine overspeed acceleration protection logic.

[0094] Generally, to ensure that when a major accident occurs where the grid voltage abnormally rises above 51.5 Hz, the steam turbine generator set will be disconnected from the grid. At this time, in the non-grid-connected operation state of the steam turbine generator set, by enabling the turbine overspeed acceleration protection logic, the rapid speed increase of the steam turbine under the load rejection condition can be inhibited, so that the steam turbine speed can be controlled below 110% of the trip speed (if the speed exceeds this value, important equipment such as turbine rotor blades breaking and rotor shaft breaking may occur due to excessive centrifugal stress), and the turbine overspeed trip caused by excessive turbine speed acceleration can be avoided. When the steam turbine generator set is in a grid-connected operation state that may endanger grid safety and nuclear safety, prohibiting enabling the turbine overspeed acceleration protection logic can avoid frequent operation of the steam turbine control valve.

[0095] In summary, the present invention discloses a steam turbine control method, which obtains the actual steam turbine speed. When the actual steam turbine speed is greater than the first turbine overspeed acceleration protection logic activation speed threshold, it controls the steam turbine to enable the turbine overspeed acceleration protection logic when the steam turbine generator set is in a non-grid-connected operation state to inhibit the rapid speed increase of the steam turbine under the load rejection condition, and prohibits enabling the turbine overspeed acceleration protection logic when the steam turbine generator set is in a grid-connected operation state. The present invention adds a grid-connected locking condition to the turbine overspeed acceleration protection logic, that is, adds a determination condition for whether the steam turbine generator set is grid-connected or non-grid-connected. When the steam turbine generator set is in a non-grid-connected condition, by enabling the turbine overspeed acceleration protection logic, the rapid speed increase of the steam turbine under the load rejection condition is inhibited, realizing the control of the steam turbine speed and avoiding the turbine overspeed trip caused by excessive turbine speed acceleration; and when the steam turbine generator set is in a grid-connected condition, the turbine overspeed acceleration protection logic is not enabled to avoid frequent operation of the steam turbine control valve and ensure grid safety and nuclear safety.

[0096] In one embodiment, step S103 may specifically include:

[0097] If the actual steam turbine speed is greater than the first turbine overspeed acceleration protection logic activation speed threshold and not greater than the second turbine overspeed acceleration protection logic activation speed threshold, obtain the steam turbine speed acceleration;

[0098] If the acceleration of the steam turbine speed is not greater than the steam turbine speed acceleration threshold, determine whether the steam turbine generator set is in grid-connected operation;

[0099] If not, when the steam turbine generator set is in non-grid-connected operation, control the steam turbine to activate the steam turbine over-acceleration protection logic, and the steam turbine over-acceleration protection does not act;

[0100] If so, when the steam turbine generator set is in grid-connected operation, control the steam turbine to prohibit the activation of the steam turbine over-acceleration protection logic.

[0101] When the GRE system monitors that A < actual steam turbine speed ≤ B, the GRE system simultaneously monitors the acceleration of the steam turbine speed. If the acceleration of the steam turbine speed ≤ X, when the steam turbine generator set is in non-grid-connected operation, only control the steam turbine to activate the steam turbine over-acceleration protection logic to suppress the rapid speed increase of the steam turbine under the load rejection condition, and at the same time the steam turbine over-acceleration protection does not act; if the acceleration of the steam turbine speed ≤ X, when the steam turbine generator set is in grid-connected operation, do not activate the steam turbine over-acceleration protection logic to avoid frequent operation of the steam turbine regulating valve, and at this time the steam turbine over-acceleration protection will not act either.

[0102] In one embodiment, step S103 may specifically include:

[0103] If the actual steam turbine speed is greater than the first steam turbine over-acceleration protection logic activation speed threshold and not greater than the second steam turbine over-acceleration protection logic activation speed threshold, obtain the acceleration of the steam turbine speed;

[0104] If the acceleration of the steam turbine speed is greater than the steam turbine speed acceleration threshold, set the protection component of the effective steam demand parameter to the set value, and determine whether the steam turbine generator set is in grid-connected operation;

[0105] If not, when the steam turbine generator set is in non-grid-connected operation, control the steam turbine to activate the steam turbine over-acceleration protection logic, control the steam turbine over-acceleration protection to act, control all the admission control valves of the steam turbine regulating system to close, and cut off the steam admission to the steam turbine; when the acceleration of the steam turbine speed decreases to less than the steam turbine speed acceleration threshold, perform closed-loop control on the opening of the admission control valve according to the output power of the steam turbine;

[0106] If so, when the steam turbine generator set is in grid-connected operation, control the steam turbine to prohibit the activation of the steam turbine over-acceleration protection logic, keep the total effective steam demand of the steam turbine unchanged, and control the steam turbine regulating valve not to act.

[0107] When the GRE system monitors that A < actual steam turbine speed ≤ B, the GRE system simultaneously monitors the acceleration of the steam turbine speed. If the acceleration of the steam turbine speed > X, set the protection component of the effective steam demand parameter to the set value M (for example, -150%). At the same time, monitor whether the steam turbine generator set is in grid-connected operation through the output port of the SAL (Speed Acceleration Limiter, over-acceleration protection system). When the steam turbine generator set is in non-grid-connected operation, control the steam turbine to engage the over-acceleration protection logic of the steam turbine to suppress the rapid speed increase of the steam turbine under the load rejection condition and control the action of the over-acceleration protection of the steam turbine. At the same time, the total effective steam demand parameter of the steam turbine control system can be subtracted by the set value M (-150%) of the protection component of the effective steam demand parameter to control the closing of all inlet steam regulating valves of the steam turbine control system and cut off the steam inlet of the steam turbine. When the acceleration of the steam turbine speed decreases to less than the threshold value of the acceleration of the steam turbine speed, perform closed-loop control on the opening of the inlet steam regulating valve according to the output power of the steam turbine. When the steam turbine generator set is in grid-connected operation, control the steam turbine not to engage the over-acceleration protection logic of the steam turbine when the steam turbine generator set is in grid-connected operation, keep the total effective steam demand of the steam turbine unchanged, and control the steam turbine regulating valve not to act.

[0108] In one embodiment, step S103 may specifically include:

[0109] If the actual speed of the steam turbine is greater than the second over-acceleration protection logic activation speed threshold of the steam turbine and not greater than the first overspeed protection logic activation speed threshold of the steam turbine, obtain the acceleration of the steam turbine speed, where the second over-acceleration protection logic activation speed threshold of the steam turbine is greater than the first overspeed protection logic activation speed threshold of the steam turbine;

[0110] If the acceleration of the steam turbine speed is not greater than the threshold value of the acceleration of the steam turbine speed, determine whether the steam turbine generator set is in grid-connected operation;

[0111] If not, control the steam turbine to engage the over-acceleration protection logic of the steam turbine when the steam turbine generator set is in non-grid-connected operation, and the over-acceleration protection of the steam turbine does not act;

[0112] If so, control the steam turbine to prohibit engaging the over-acceleration protection logic of the steam turbine when the steam turbine generator set is in grid-connected operation.

[0113] If the acceleration of the steam turbine speed is greater than the threshold value of the acceleration of the steam turbine speed and the duration for which the acceleration of the steam turbine speed is greater than the threshold value of the acceleration of the steam turbine speed is less than the first preset time period, determine whether the steam turbine generator set is in grid-connected operation;

[0114] If not, when the steam turbine is in a non-grid-connected operation state of the steam turbine generator set, control the steam turbine to activate the over-acceleration protection logic of the steam turbine, and the over-acceleration protection of the steam turbine acts;

[0115] If so, when the steam turbine is in a grid-connected operation state of the steam turbine generator set, control the steam turbine to prohibit activating the over-acceleration protection logic of the steam turbine.

[0116] When the GRE system monitors that B < actual steam turbine speed ≤ C, the GRE system simultaneously monitors the acceleration of the steam turbine speed. If the acceleration of the steam turbine speed ≤ X, when the steam turbine generator set is in a non-grid-connected operation state, only control the steam turbine to activate the over-acceleration protection logic of the steam turbine to suppress the rapid speed increase of the steam turbine under the load rejection condition, and at the same time, the over-acceleration protection of the steam turbine does not act; when the steam turbine generator set is in a grid-connected operation state, do not activate the over-acceleration protection logic of the steam turbine to avoid frequent actions of the steam turbine regulating valve, and at this time, the over-acceleration protection of the steam turbine will not act; if the acceleration of the steam turbine speed > X, but the duration of the acceleration of the steam turbine speed > X is less than the first preset time period (for example, 0.1 s), when the steam turbine generator set is in a non-grid-connected operation state, control the steam turbine to activate the over-acceleration protection logic of the steam turbine to suppress the rapid speed increase of the steam turbine under the load rejection condition, and at the same time, the over-acceleration protection of the steam turbine acts; when the steam turbine generator set is in a grid-connected operation state, do not activate the over-acceleration protection logic of the steam turbine to avoid frequent actions of the steam turbine regulating valve, and at this time, the over-acceleration protection of the steam turbine will not act.

[0117] In one embodiment, step S103 may specifically include:

[0118] If the actual steam turbine speed is greater than the activation speed threshold of the second over-acceleration protection logic of the steam turbine and not greater than the activation speed threshold of the first overspeed protection logic of the steam turbine, obtain the acceleration of the steam turbine speed, where the activation speed threshold of the second over-acceleration protection logic of the steam turbine is greater than the activation speed threshold of the first overspeed protection logic of the steam turbine;

[0119] If the acceleration of the steam turbine speed is greater than the acceleration threshold of the steam turbine speed and lasts for the first preset time period, set the protection component of the effective steam demand parameter to the set value, and determine whether the steam turbine generator set is in a grid-connected operation state;

[0120] If not, when the steam turbine is in a non-grid-connected operation state of the steam turbine generator set, control the steam turbine to activate the over-acceleration protection logic of the steam turbine, control the over-acceleration protection of the steam turbine to act, control all the admission control valves of the steam turbine regulating system to close, and cut off the steam supply to the steam turbine; when the time for cutting off the steam supply to the steam turbine reaches the second preset time period, when the acceleration of the steam turbine speed decreases to less than the acceleration threshold of the steam turbine speed, perform closed-loop control on the opening of the admission control valve according to the output power of the steam turbine;

[0121] If so, prohibit the input of the turbine overspeed acceleration protection logic, keep the value of the protection component of the effective steam demand parameter unchanged, and keep the opening degree of the steam admission regulating valve unchanged.

[0122] When the GRE system monitors that B < actual turbine speed ≤ C, the GRE system simultaneously monitors the turbine speed acceleration. If the duration for which the turbine speed acceleration > X is not less than the first preset time period (e.g., 0.1 s), set the protection component of the effective steam demand parameter to the set value M (e.g., -150%). At the same time, the SAL output port monitors whether the unit is in grid-connected operation. When the turbo-generator set is in non-grid-connected operation, input the turbine overspeed acceleration protection logic to suppress the rapid speed increase of the turbine under the load rejection condition, and control the action of the turbine overspeed acceleration protection, control all the steam admission regulating valves of the turbine regulating system to close, and cut off the steam admission to the turbine; when the time for cutting off the steam admission to the turbine reaches the second preset time period (e.g., 0.5 s) and the turbine speed acceleration drops to less than X, perform closed-loop control on the opening degree of the steam admission regulating valve according to the output power of the turbine. When the turbo-generator set is in grid-connected operation, do not input the turbine overspeed acceleration protection logic to avoid frequent actions of the turbine regulating valve, keep the value of the protection component of the effective steam demand parameter unchanged, and keep the opening degree of the steam admission regulating valve unchanged.

[0123] In one embodiment, step S103 may specifically include:

[0124] When the actual turbine speed is greater than the effective speed threshold of the first turbine overspeed protection logic and not greater than the effective speed threshold of the second turbine overspeed protection logic, set the protection component of the effective steam demand parameter to the set value, and determine whether the turbo-generator set is in grid-connected operation, where the effective speed threshold of the second turbine overspeed protection logic is greater than the effective speed threshold of the first turbine overspeed protection logic;

[0125] If not, when the turbine speed acceleration is not greater than the turbine speed acceleration threshold, control the effective steam demand parameter and the steam admission regulating valve to remain unchanged; when the turbine speed acceleration is greater than the turbine speed acceleration threshold, control the action of the turbine overspeed acceleration protection. If the time for which the turbine speed acceleration is greater than the turbine speed acceleration threshold lasts for the first preset time period, control the maintenance time of the action of the turbine overspeed acceleration protection to reach the second preset time period;

[0126] If so, the turbine overacceleration protection logic is prohibited, and the turbine overspeed protection logic is put into operation. By outputting the difference between the total effective steam demand parameter and the protection component of the effective steam demand parameter, all the steam inlet regulating valves of the turbine control system are controlled to be closed, and the turbine steam inlet is cut off; when the turbine speed acceleration is reduced to less than the speed threshold value for the effectiveness of the first turbine overspeed protection logic, the opening of the steam inlet regulating valve is closed-loop controlled according to the turbine output power.

[0127] When the GRE system detects that C is less than the actual turbine speed ≤ D, the effective steam demand parameter protection component is set to the set value M (for example, -150%), and the SAL output port monitors whether the unit is in the grid-connected operation state. When the steam turbine generator set is in the non-grid-connected operation state, when the turbine speed acceleration is ≤X, the effective steam demand parameter and the steam inlet regulating valve are controlled to remain unchanged; when the turbine speed acceleration is greater than X, the steam turbine over-acceleration protection action is controlled. If the time when the turbine speed acceleration is greater than X lasts for a first preset time period (for example, 0.1s), the steam turbine over-acceleration protection action is controlled to maintain for a second preset time period. When the steam turbine generator set is in the grid-connected operation state, the steam turbine over-acceleration protection logic is not put into operation, and the steam turbine overspeed protection logic is put into operation, and the difference between the effective steam demand parameter and the effective steam demand parameter protection component is output through the dual-channel selection unit, and all the steam inlet regulating valves of the steam turbine regulation system are controlled to be closed to cut off the steam inlet of the steam turbine. When the turbine speed drops below C, the opening of the steam inlet regulating valve is closed-loop controlled according to the turbine output power.

[0128] It should be noted that the value of C is preferably 103% of the rated speed of the steam turbine, and the value of D is preferably 107% of the rated speed of the steam turbine. In this embodiment, when the GRE system monitors that C < actual speed of the steam turbine ≤ D, the steam turbine generator set is controlled when it is in the grid-connected operation state and the non-grid-connected operation state. During the grid-connected period of the steam turbine generator set, the turbine overspeed protection action value is actually adjusted from 107% of the rated speed of the steam turbine to 103% of the rated speed of the steam turbine, thereby suppressing the turbine speed from soaring in the high-frequency state of the power grid.

[0129] In one embodiment, step S103 may specifically include:

[0130] When the actual speed of the steam turbine is greater than the speed threshold of the second steam turbine overspeed protection logic, the effective steam demand parameter protection component is set to the set value, and it is determined whether the steam turbine generator set is in the grid-connected operation state;

[0131] If not, control the turbine over-acceleration protection logic and the turbine overspeed protection logic to be enabled, and the turbine overspeed protection takes precedence over the turbine over-acceleration protection. By outputting the difference between the total effective steam demand parameter and the protection component of the effective steam demand parameter, control all the admission control valves of the turbine regulating system to close and cut off the steam admission to the turbine; when the turbine speed drops below the second turbine overspeed protection logic activation speed threshold, perform closed-loop control on the opening of the admission control valve according to the turbine output power.

[0132] If so, prohibit enabling the turbine over-acceleration protection logic, and enable the turbine overspeed protection logic. Output the difference between the total effective steam demand parameter and the protection component of the effective steam demand parameter, control all the admission control valves of the turbine regulating system to close and cut off the steam admission to the turbine; when the turbine speed drops below the first turbine overspeed protection logic activation speed threshold, perform closed-loop control on the opening of the admission control valve according to the turbine output power.

[0133] When the GRE system monitors that the actual turbine speed > D, set the protection component of the effective steam demand parameter to the set value M. At the same time, the SAL output port monitors whether the unit is in grid-connected operation. When the turbo-generator set is in non-grid-connected operation, both the turbine over-acceleration protection logic and the turbine overspeed protection logic are enabled, and the turbine overspeed protection takes precedence over the turbine over-acceleration protection. By outputting the difference between the total effective steam demand parameter and the protection component of the effective steam demand parameter, control all the admission control valves of the turbine regulating system to close and cut off the steam admission to the turbine. When the turbine speed drops below D, perform closed-loop control on the opening of the admission control valve according to the turbine output power. When the turbo-generator set is in grid-connected operation, prohibit enabling the turbine over-acceleration protection logic, and enable the turbine overspeed protection logic. By outputting the difference between the total effective steam demand parameter and the protection component of the effective steam demand parameter, control all the admission control valves of the turbine regulating system to close and cut off the steam admission to the turbine. When the turbine speed drops below C, perform closed-loop control on the opening of the admission control valve according to the turbine output power.

[0134] In summary, by adding the judgment conditions for grid connection and non-grid connection between the steam turbine generator set and the power grid, the present invention enables the steam turbine generator set not to activate the steam turbine over-acceleration protection logic under the grid connection conditions that may endanger the power grid safety and nuclear safety, thereby avoiding the frequent operation of the steam turbine regulating valve. Moreover, in order to ensure that when the power grid abnormally rises above 51.5 Hz in a major accident condition and the steam turbine generator set is in a non-grid connection condition, the steam turbine speed can be controlled below the turbine trip speed (if the steam turbine speed exceeds the turbine trip speed, important equipment such as the fracture of the steam turbine rotor blades and the breakage of the rotor shaft will be caused due to excessive centrifugal stress), the effective speed threshold D of the second steam turbine overspeed protection logic (the value of D is, for example, 107% of the rated steam turbine speed) is moved forward to the safe effective speed threshold C of the first steam turbine overspeed protection logic (the value of C is, for example, 103% of the rated steam turbine speed), thereby achieving the avoidance of the frequent operation of the steam turbine regulating valve, ensuring the power grid safety and nuclear safety, and avoiding the damage of important equipment under severe power grid conditions.

[0135] It should be noted that the use of the steam turbine control method disclosed in the present invention can greatly improve the benefits of the steam turbine generator set. The test results are as follows:

[0136] 1. The present invention can effectively avoid the power grid instability under short power grid faults or bipolar blocking conditions of UHVDC transmission lines, avoid large-area regional power outages, and reduce direct economic losses (estimated by the power generation ratio method based on the unit starting within 8 hours after the power outage) = lack of power supply (kWh) × power generation ratio (yuan / kWh) = 572 million kWh × 9.3 yuan / kWh = 5.3196 billion yuan.

[0137] 2. The present invention can effectively avoid the tripping of nuclear power units due to the over-acceleration protection logic, and reduce the direct loss of power generation income (based on the unit reaching criticality and starting within 48 hours after shutdown) = 8.45 million yuan / unit-day × 6 units × 48 hours ÷ 24 hours = 101.4 million yuan.

[0138] 3. The present invention will create a total economic benefit = avoid regional power outage loss + shutdown and reactor trip power generation income loss = 5.3196 billion yuan + 101.4 million yuan = 5.421 billion yuan.

[0139] Corresponding to the above method embodiment, the present invention also discloses a steam turbine control device.

[0140] See Figure 2 , a structural schematic diagram of a steam turbine control device disclosed in an embodiment of the present invention. The device is applied to GRE and may include:

[0141] A speed acquisition unit 201 for acquiring the actual speed of the steam turbine.

[0142] In practical applications, the actual speed of the steam turbine can be obtained through sensors such as magnetoelectric speed sensors and Hall effect sensors.

[0143] A judgment unit 202 is configured to judge whether the actual speed of the steam turbine is greater than a first steam turbine over-acceleration protection logic activation speed threshold.

[0144] It should be noted that in practical applications, first, the steam turbine over-acceleration protection logic needs to be activated, and then it is further determined whether to execute the steam turbine over-acceleration protection logic, that is, whether the steam turbine over-acceleration protection operates.

[0145] A control unit 203 is configured to, when the judgment unit determines that it is the case, control the steam turbine to activate the steam turbine over-acceleration protection logic when the turbo-generator set is in a non-grid-connected operation state to suppress the rapid speed increase of the steam turbine under the load rejection condition, and prohibit the activation of the steam turbine over-acceleration protection logic when the turbo-generator set is in a grid-connected operation state.

[0146] Generally, to ensure that the turbo-generator set is disconnected from the power grid when the power grid abnormally rises above 51.5 Hz in a major accident condition. At this time, in the non-grid-connected operation state of the turbo-generator set, by activating the steam turbine over-acceleration protection logic, the rapid speed increase of the steam turbine under the load rejection condition can be suppressed, so that the speed of the steam turbine can be controlled below 110% of the non-trip speed (if the speed exceeds this value, important equipment such as the fracture of the steam turbine rotor blades and the breakage of the rotor shaft may be caused due to excessive centrifugal stress), and the over-speed trip of the steam turbine due to excessive acceleration of the steam turbine speed can be avoided. When the turbo-generator set is in a grid-connected operation state that may endanger the power grid safety and nuclear safety, prohibiting the activation of the steam turbine over-acceleration protection logic can avoid the frequent operation of the steam turbine control valve.

[0147] In summary, the present invention discloses a steam turbine control device, which obtains the actual speed of the steam turbine. When the actual speed of the steam turbine is greater than the effective speed threshold of the first steam turbine overspeed acceleration protection logic, it controls the steam turbine to activate the steam turbine overspeed acceleration protection logic when the steam turbine generator set is in a non-grid-connected operation state, so as to inhibit the rapid speed increase of the steam turbine under the load rejection condition, and prohibits the activation of the steam turbine overspeed acceleration protection logic when the steam turbine generator set is in a grid-connected operation state. The present invention adds a grid connection locking condition to the steam turbine overspeed acceleration protection logic, that is, it adds a determination condition for whether the steam turbine generator set is grid-connected or non-grid-connected with the power grid. When the steam turbine generator set is in a non-grid-connected condition, by activating the steam turbine overspeed acceleration protection logic, the rapid speed increase of the steam turbine under the load rejection condition is inhibited, the control of the steam turbine speed is realized, and the overspeed trip of the steam turbine due to excessive speed acceleration of the steam turbine is avoided; and when the steam turbine generator set is in a grid-connected condition, the steam turbine overspeed acceleration protection logic is not activated to avoid frequent operation of the steam turbine regulating valve and ensure the safety of the power grid and nuclear safety.

[0148] In one embodiment, the steam turbine control device may further include:

[0149] A prohibition input unit, configured to, if the actual speed of the steam turbine is not greater than the effective speed threshold of the first steam turbine overspeed acceleration protection logic, control both the steam turbine overspeed acceleration protection logic and the steam turbine overspeed protection logic to be prohibited from being input.

[0150] In one embodiment, the control unit 203 may specifically be configured to:

[0151] If the actual speed of the steam turbine is greater than the effective speed threshold of the first steam turbine overspeed acceleration protection logic and not greater than the effective speed threshold of the second steam turbine overspeed acceleration protection logic, obtain the steam turbine speed acceleration;

[0152] If the steam turbine speed acceleration is not greater than the steam turbine speed acceleration threshold, determine whether the steam turbine generator set is in a grid-connected operation state;

[0153] If not, control the steam turbine to activate the steam turbine overspeed acceleration protection logic when the steam turbine generator set is in a non-grid-connected operation state, and the steam turbine overspeed acceleration protection does not act;

[0154] If so, control the steam turbine to prohibit the activation of the steam turbine overspeed acceleration protection logic when the steam turbine generator set is in a grid-connected operation state.

[0155] In one embodiment, the control unit 203 may specifically be configured to:

[0156] If the actual speed of the steam turbine is greater than the effective speed threshold of the first steam turbine overspeed acceleration protection logic and not greater than the effective speed threshold of the second steam turbine overspeed acceleration protection logic, obtain the steam turbine speed acceleration;

[0157] If the rotational speed acceleration of the steam turbine is greater than the steam turbine rotational speed acceleration threshold, set the protection component of the effective steam demand parameter to a set value, and determine whether the steam turbine generator set is in a grid-connected operation state;

[0158] If not, when the steam turbine generator set is in a non-grid-connected operation state, control the steam turbine to activate the steam turbine over-acceleration protection logic, control the steam turbine over-acceleration protection to act, control all the admission control valves of the steam turbine regulating system to close, and cut off the steam admission to the steam turbine; when the rotational speed acceleration of the steam turbine decreases to be less than the steam turbine rotational speed acceleration threshold, perform closed-loop control on the opening degree of the admission control valve according to the output power of the steam turbine;

[0159] If so, when the steam turbine generator set is in a grid-connected operation state, control the steam turbine to prohibit activating the steam turbine over-acceleration protection logic, keep the total effective steam demand of the steam turbine unchanged, and control the steam turbine control valve not to act.

[0160] In one embodiment, the control unit 203 may specifically be used for:

[0161] If the actual rotational speed of the steam turbine is greater than the second steam turbine over-acceleration protection logic activation rotational speed threshold and not greater than the first steam turbine over-speed protection logic activation rotational speed threshold, obtain the rotational speed acceleration of the steam turbine, where the second steam turbine over-acceleration protection logic activation rotational speed threshold is less than the first steam turbine over-speed protection logic activation rotational speed threshold;

[0162] If the rotational speed acceleration of the steam turbine is not greater than the steam turbine rotational speed acceleration threshold, determine whether the steam turbine generator set is in a grid-connected operation state;

[0163] If not, when the steam turbine generator set is in a non-grid-connected operation state, control the steam turbine to activate the steam turbine over-acceleration protection logic, and the steam turbine over-acceleration protection does not act;

[0164] If so, when the steam turbine generator set is in a grid-connected operation state, control the steam turbine to prohibit activating the steam turbine over-acceleration protection logic;

[0165] If the rotational speed acceleration of the steam turbine is greater than the steam turbine rotational speed acceleration threshold and the duration for which the rotational speed acceleration of the steam turbine is greater than the steam turbine rotational speed acceleration threshold is less than the first preset time period, determine whether the steam turbine generator set is in a grid-connected operation state;

[0166] If not, when the steam turbine generator set is in a non-grid-connected operation state, control the steam turbine to activate the steam turbine over-acceleration protection logic, and the steam turbine over-acceleration protection acts;

[0167] If so, when the steam turbine is in the grid-connected operation state of the steam turbine generator set, prohibit the input of the steam turbine over-acceleration protection logic.

[0168] In one embodiment, the control unit 203 may specifically be configured to:

[0169] If the actual speed of the steam turbine is greater than the second steam turbine over-acceleration protection logic activation speed threshold and not greater than the first steam turbine overspeed protection logic activation speed threshold, obtain the steam turbine speed acceleration, where the second steam turbine over-acceleration protection logic activation speed threshold is less than the first steam turbine overspeed protection logic activation speed threshold;

[0170] If the steam turbine speed acceleration is greater than the steam turbine speed acceleration threshold and lasts for a first preset time period, set the effective steam demand parameter protection component to a set value, and determine whether the steam turbine generator set is in the grid-connected operation state;

[0171] If not, when the steam turbine is in the non-grid-connected operation state of the steam turbine generator set, input the steam turbine over-acceleration protection logic, control the steam turbine over-acceleration protection to act, control all the admission control valves of the steam turbine regulating system to close, and cut off the steam inlet of the steam turbine; when the time for cutting off the steam inlet of the steam turbine reaches a second preset time period, when the steam turbine speed acceleration drops to less than the steam turbine speed acceleration threshold, perform closed-loop control on the opening of the admission control valve according to the output power of the steam turbine;

[0172] If so, prohibit the input of the steam turbine over-acceleration protection logic, keep the value of the effective steam demand parameter protection component unchanged, and keep the opening of the admission control valve unchanged.

[0173] In one embodiment, the control unit 203 may specifically be configured to:

[0174] When the actual speed of the steam turbine is greater than the first steam turbine overspeed protection logic activation speed threshold and not greater than the second steam turbine overspeed protection logic activation speed threshold, set the effective steam demand parameter protection component to a set value, and determine whether the steam turbine generator set is in the grid-connected operation state, where the first steam turbine overspeed protection logic activation speed threshold is greater than the first steam turbine over-acceleration protection logic activation speed threshold;

[0175] Otherwise, when the acceleration of the steam turbine speed is not greater than the steam turbine speed acceleration threshold, the effective steam demand parameter and the steam inlet regulating valve are controlled to remain unchanged; when the acceleration of the steam turbine speed is greater than the steam turbine speed acceleration threshold, the steam turbine over-acceleration protection action is controlled. If the time when the acceleration of the steam turbine speed is greater than the steam turbine speed acceleration threshold lasts for a first preset time period, the maintenance time of the steam turbine over-acceleration protection action is controlled to reach a second preset time period;

[0176] If so, the steam turbine over-acceleration protection logic is prohibited from being put into operation, and the steam turbine overspeed protection logic is put into operation. The difference between the total effective steam demand parameter and the protected component of the effective steam demand parameter is output through the dual-path selection unit to control all the steam inlet regulating valves of the steam turbine regulating system to close and cut off the steam inlet of the steam turbine; when the steam turbine speed drops below the first steam turbine overspeed protection logic activation speed threshold, the opening of the steam inlet regulating valve is closed-loop controlled according to the output power of the steam turbine.

[0177] In one embodiment, the control unit 203 may specifically be used for:

[0178] When the actual speed of the steam turbine is greater than the second steam turbine overspeed protection logic activation speed threshold, the protected component of the effective steam demand parameter is set to a set value, and it is judged whether the steam turbine generator set is in a grid-connected operation state;

[0179] If not, the steam turbine over-acceleration protection logic and the steam turbine overspeed protection logic are controlled to be put into operation, and the steam turbine overspeed protection takes precedence over the steam turbine over-acceleration protection action. By outputting the difference between the total effective steam demand parameter and the protected component of the effective steam demand parameter, and controlling all the steam inlet regulating valves of the steam turbine regulating system to close and cut off the steam inlet of the steam turbine; when the steam turbine speed drops below the second steam turbine overspeed protection logic activation speed threshold, the opening of the steam inlet regulating valve is closed-loop controlled according to the output power of the steam turbine;

[0180] If so, the steam turbine over-acceleration protection logic is prohibited from being put into operation, and the steam turbine overspeed protection logic is put into operation. By outputting the difference between the total effective steam demand parameter and the protected component of the effective steam demand parameter, all the steam inlet regulating valves of the steam turbine regulating system are controlled to close and cut off the steam inlet of the steam turbine; when the steam turbine speed drops below the first steam turbine overspeed protection logic activation speed threshold, the opening of the steam inlet regulating valve is closed-loop controlled according to the output power of the steam turbine.

[0181] It should be noted that for the specific working principles of the components in the device embodiment, please refer to the corresponding parts of the method embodiment, which will not be elaborated here.

[0182] Corresponding to the above embodiments, the present invention also discloses a computer storage medium storing at least one instruction, and when the at least one instruction is executed by a processor, the steps shown in the embodiments of the steam turbine control method are implemented.

[0183] Corresponding to the above embodiments, as Figure 3 shown, the present invention also provides a schematic structural diagram of an electronic device, and the electronic device may include: a processor 1 and a memory 2;

[0184] Among them, the processor 1 and the memory 2 communicate with each other through a communication bus 3;

[0185] The processor 1 is used to execute at least one instruction;

[0186] The memory 2 is used to store at least one instruction;

[0187] The processor 1 may be a central processing unit (CPU), or a specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of the present invention.

[0188] The memory 2 may include a high-speed RAM memory, and may also include non-volatile memory, such as at least one disk memory.

[0189] Among them, the processor executes at least one instruction to implement the steps shown in the embodiments of the steam turbine control method.

[0190] Finally, it should also be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "including a..." does not exclude the existence of additional identical elements in the process, method, article or device including the said element.

[0191] Each embodiment in this specification is described in a progressive manner, and the key points of each embodiment are the differences from other embodiments. The same and similar parts among the embodiments can be referred to each other.

[0192] The foregoing description of the disclosed embodiments enables those skilled in the art to practice or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A steam turbine control method, characterized in that, Including: Obtain the actual speed of the steam turbine; Judge whether the actual speed of the steam turbine is greater than the effective speed threshold of the first steam turbine overspeed acceleration protection logic; If so, when the steam turbine generator set is in a non-parallel operation state, control the steam turbine to activate the steam turbine overspeed acceleration protection logic to suppress the rapid speed increase of the steam turbine under the load rejection condition, and when the steam turbine generator set is in a parallel operation state, prohibit activating the steam turbine overspeed acceleration protection logic.

2. The steam turbine control method according to claim 1, wherein Also including: If the actual speed of the steam turbine is not greater than the effective speed threshold of the first steam turbine overspeed acceleration protection logic, control both the steam turbine overspeed acceleration protection logic and the steam turbine overspeed protection logic to be prohibited from being activated.

3. The steam turbine control method according to claim 1 or 2, characterized in that, The control of activating the steam turbine overspeed acceleration protection logic when the steam turbine generator set is in a non-parallel operation state to suppress the rapid speed increase of the steam turbine under the load rejection condition, and prohibiting activating the steam turbine overspeed acceleration protection logic when the steam turbine generator set is in a parallel operation state includes: If the actual speed of the steam turbine is greater than the effective speed threshold of the first steam turbine overspeed acceleration protection logic and not greater than the effective speed threshold of the second steam turbine overspeed acceleration protection logic, obtain the steam turbine speed acceleration; If the steam turbine speed acceleration is not greater than the steam turbine speed acceleration threshold, judge whether the steam turbine generator set is in a parallel operation state; If not, when the steam turbine generator set is in a non-parallel operation state, control the steam turbine to activate the steam turbine overspeed acceleration protection logic, and the steam turbine overspeed acceleration protection does not act; If so, when the steam turbine generator set is in a parallel operation state, control the steam turbine to prohibit activating the steam turbine overspeed acceleration protection logic.

4. The steam turbine control method according to claim 1 or 2, characterized in that The control of activating the steam turbine overspeed acceleration protection logic when the steam turbine generator set is in a non-parallel operation state to suppress the rapid speed increase of the steam turbine under the load rejection condition, and prohibiting activating the steam turbine overspeed acceleration protection logic when the steam turbine generator set is in a parallel operation state includes: If the actual speed of the steam turbine is greater than the effective speed threshold of the first steam turbine overspeed acceleration protection logic and not greater than the effective speed threshold of the second steam turbine overspeed acceleration protection logic, obtain the steam turbine speed acceleration; If the steam turbine speed acceleration is greater than the steam turbine speed acceleration threshold, set the protection component of the effective steam demand parameter to the set value, and judge whether the steam turbine generator set is in a parallel operation state; If not, when the steam turbine generator set is in a non-parallel operation state, control the steam turbine to activate the steam turbine overspeed acceleration protection logic, control the steam turbine overspeed acceleration protection to act, control all the admission control valves of the steam turbine regulating system to close, and cut off the steam admission to the steam turbine; when the steam turbine speed acceleration drops below the steam turbine speed acceleration threshold, perform closed-loop control on the opening of the admission control valve according to the steam turbine output power; If so, when the steam turbine generator set is in a parallel operation state, control the steam turbine to prohibit activating the steam turbine overspeed acceleration protection logic, keep the total effective steam demand of the steam turbine unchanged, and control the steam turbine control valve not to act.

5. The steam turbine control method according to claim 1, characterized in that When the steam turbine generator unit is in a non-grid-connected operation state, the steam turbine super-acceleration protection logic is put into operation to suppress the rapid speed increase of the steam turbine under the load rejection condition, and when the steam turbine generator unit is in a grid-connected operation state, the steam turbine super-acceleration protection logic is prohibited from being put into operation, including: If the actual speed of the steam turbine is greater than the second steam turbine super-acceleration protection logic activation speed threshold and not greater than the first steam turbine over-speed protection logic activation speed threshold, obtain the steam turbine speed acceleration, where the second steam turbine super-acceleration protection logic activation speed threshold is greater than the first steam turbine super-acceleration protection logic activation speed threshold; If the steam turbine speed acceleration is not greater than the steam turbine speed acceleration threshold, determine whether the steam turbine generator unit is in a grid-connected operation state; If not, control the steam turbine to put into operation the steam turbine super-acceleration protection logic when the steam turbine generator unit is in a non-grid-connected operation state, and the steam turbine super-acceleration protection does not act; If so, control the steam turbine to prohibit the input of the steam turbine super-acceleration protection logic when the steam turbine generator unit is in a grid-connected operation state; If the steam turbine speed acceleration is greater than the steam turbine speed acceleration threshold and the duration for which the steam turbine speed acceleration is greater than the steam turbine speed acceleration threshold is less than the first preset time period, determine whether the steam turbine generator unit is in a grid-connected operation state; If not, control the steam turbine to put into operation the steam turbine super-acceleration protection logic when the steam turbine generator unit is in a non-grid-connected operation state, and the steam turbine super-acceleration protection acts; If so, control the steam turbine to prohibit the input of the steam turbine super-acceleration protection logic when the steam turbine generator unit is in a grid-connected operation state.

6. The steam turbine control method according to claim 1 or 5, characterized in that When the steam turbine generator unit is in a non-grid-connected operation state, the steam turbine super-acceleration protection logic is put into operation to suppress the rapid speed increase of the steam turbine under the load rejection condition, and when the steam turbine generator unit is in a grid-connected operation state, the steam turbine super-acceleration protection logic is prohibited from being put into operation, including: If the actual speed of the steam turbine is greater than the second steam turbine super-acceleration protection logic activation speed threshold and not greater than the first steam turbine over-speed protection logic activation speed threshold, obtain the steam turbine speed acceleration, where the second steam turbine super-acceleration protection logic activation speed threshold is greater than the first steam turbine super-acceleration protection logic activation speed threshold; If the steam turbine speed acceleration is greater than the steam turbine speed acceleration threshold and lasts for the first preset time period, set the effective steam demand parameter protection component to a set value, and determine whether the steam turbine generator unit is in a grid-connected operation state; If not, control the steam turbine to put into operation the steam turbine super-acceleration protection logic when the steam turbine generator unit is in a non-grid-connected operation state, control the steam turbine super-acceleration protection to act, control all the admission control valves of the steam turbine regulating system to close, and cut off the steam supply to the steam turbine; when the time for cutting off the steam supply to the steam turbine reaches the second preset time period, when the steam turbine speed acceleration drops to less than the steam turbine speed acceleration threshold, perform closed-loop control on the opening of the admission control valve according to the steam turbine output power; If so, prohibit the input of the turbine super-acceleration protection logic, keep the value of the protection component of the effective steam demand parameter unchanged, and keep the opening degree of the steam admission regulating valve unchanged.

7. The steam turbine control method according to claim 1, characterized in that The control of the turbine to input the turbine super-acceleration protection logic when the turbo-generator unit is in a non-grid-connected operation state to suppress the rapid speed increase of the turbine under the load rejection condition, and prohibit the input of the turbine super-acceleration protection logic when the turbo-generator unit is in a grid-connected operation state, includes: When the actual speed of the turbine is greater than the first turbine overspeed protection logic activation speed threshold and not greater than the second turbine overspeed protection logic activation speed threshold, set the protection component of the effective steam demand parameter to a set value, and determine whether the turbo-generator unit is in a grid-connected operation state, where the second turbine overspeed protection logic activation speed threshold is greater than the first turbine overspeed protection logic activation speed threshold; If not, when the turbine speed acceleration is not greater than the turbine speed acceleration threshold, control the effective steam demand parameter and the steam admission regulating valve to remain unchanged; when the turbine speed acceleration is greater than the turbine speed acceleration threshold, control the turbine super-acceleration protection to act. If the time when the turbine speed acceleration is greater than the turbine speed acceleration threshold lasts for a first preset time period, control the action maintenance time of the turbine super-acceleration protection to reach a second preset time period; If so, prohibit the input of the turbine super-acceleration protection logic, and input the turbine overspeed protection logic. By outputting the difference between the total effective steam demand parameter and the protection component of the effective steam demand parameter, control all the steam admission regulating valves of the turbine regulating system to close and cut off the steam admission to the turbine; when the turbine speed acceleration decreases to less than the first turbine overspeed protection logic activation speed threshold, perform closed-loop control on the opening degree of the steam admission regulating valve according to the turbine output power.

8. The steam turbine control method according to claim 1 or 7, characterized in that The control of the turbine to input the turbine super-acceleration protection logic when the turbo-generator unit is in a non-grid-connected operation state to suppress the rapid speed increase of the turbine under the load rejection condition, and prohibit the input of the turbine super-acceleration protection logic when the turbo-generator unit is in a grid-connected operation state, includes: When the actual speed of the turbine is greater than the second turbine overspeed protection logic activation speed threshold, set the protection component of the effective steam demand parameter to a set value, and determine whether the turbo-generator unit is in a grid-connected operation state; If not, control the input of the turbine super-acceleration protection logic and the turbine overspeed protection logic, and the turbine overspeed protection takes precedence over the turbine super-acceleration protection action. By outputting the difference between the total effective steam demand parameter and the protection component of the effective steam demand parameter, control all the steam admission regulating valves of the turbine regulating system to close and cut off the steam admission to the turbine; when the turbine speed decreases to less than the second turbine overspeed protection logic activation speed threshold, perform closed-loop control on the opening degree of the steam admission regulating valve according to the turbine output power; If so, prohibit the input of the steam turbine super-acceleration protection logic and input the steam turbine overspeed protection logic. By outputting the difference between the total effective steam demand parameter and the protection component of the effective steam demand parameter, control all the admission control valves of the steam turbine regulating system to close and cut off the steam admission to the steam turbine. When the steam turbine speed drops below the first steam turbine overspeed protection logic activation speed threshold, perform closed-loop control on the opening of the admission control valve according to the output power of the steam turbine.

9. A steam turbine control device, characterized in that, It includes: A speed acquisition unit for acquiring the actual speed of the steam turbine; A judgment unit for judging whether the actual speed of the steam turbine is greater than the first steam turbine super-acceleration protection logic activation speed threshold; A control unit for, when the judgment unit judges yes, controlling the steam turbine to input the steam turbine super-acceleration protection logic when the turbo-generator set is in a non-grid-connected operation state to suppress the rapid speed increase of the steam turbine under the load rejection condition, and prohibiting the input of the steam turbine super-acceleration protection logic when the turbo-generator set is in a grid-connected operation state.

10. A computer storage medium, characterized in that, The computer storage medium stores at least one instruction, and when the at least one instruction is executed by a processor, it implements the steam turbine control method according to any one of claims 1 to 8.

11. An electronic device, characterized in that, The electronic device includes: a memory and a processor; The memory is used for storing at least one instruction; The processor is used for executing the at least one instruction to implement the steam turbine control method according to any one of claims 1 to 8.

Images