A steam turbine control method and related device

Abstract

The present invention discloses a steam turbine control method and related device, relating to the field of steam turbines. The method comprises: obtaining the actual speed of the steam turbine; when the actual speed of the steam turbine is greater than the speed threshold at which the first steam turbine over-acceleration protection logic takes effect, controlling the steam turbine to activate the steam turbine over-acceleration protection logic when the steam turbine generator set is in a non-grid-connected operating state, thereby suppressing the rapid speed increase of the steam turbine under load rejection conditions; and prohibiting the activation of the steam turbine over-acceleration protection logic when the steam turbine generator set is in a grid-connected operating state. The present invention adds a grid-connected lockout condition to the steam turbine over-acceleration protection logic; when the steam turbine generator set is in a non-grid-connected operating state, the steam turbine over-acceleration protection logic is activated to prevent the turbine from overspeeding due to excessive acceleration; when the steam turbine generator set is in a grid-connected operating state, the steam turbine over-acceleration protection logic is not activated to prevent frequent operation of the turbine regulating valve, thereby ensuring power grid safety and nuclear safety.

Description

Technical Field

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

[0002] When the steam turbine generator set is in grid-connected or non-grid-connected operation, when the turbine speed exceeds the turbine speed threshold and the turbine speed rises rapidly to exceed the acceleration threshold, the turbine over-acceleration protection logic is executed, specifically: the turbine high-pressure regulating valve and the medium-pressure regulating valve are closed to reduce the turbine speed to prevent the turbine speed from exceeding the unit trip speed.

[0003] However, when the turbine over-acceleration protection logic is executed under grid-connected conditions, the turbine regulating valve's response will be inconsistent with the grid frequency regulation, causing disturbances to the grid and even causing large frequency fluctuations and grid instability, thereby endangering grid security. Furthermore, when the turbine over-acceleration protection logic is restored, the turbine regulating valve will quickly open. Due to the delayed closure of the turbine bypass discharge system, the pressure in the nuclear island steam generator of the nuclear power turbine will drop rapidly, triggering an automatic shutdown of the nuclear island and thus endangering nuclear safety. In other words, the more frequently the turbine over-acceleration protection logic triggers the turbine regulating valve, the greater the impact on grid and nuclear safety.

[0004] Therefore, how to provide a steam turbine control method to effectively reduce the impact of the steam turbine overacceleration protection logic on power grid safety and nuclear safety has become a technical problem that technical personnel in this field urgently need to solve. 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 steam turbine over-acceleration protection logic on power grid safety and nuclear safety.

[0006] A steam turbine control method, comprising:

[0007] Get the actual speed of the turbine;

[0008] Determining whether the actual speed of the steam turbine is greater than a first steam turbine over-acceleration protection logic effective speed threshold;

[0009] If so, 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 to suppress the rapid speed increase of the steam turbine under the load rejection condition, and the activation of the steam turbine over-acceleration protection logic is prohibited when the steam turbine generator set is in a grid-connected operation state.

[0010] Optionally, it also includes:

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

[0012] Optionally, the controlling of 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 suppress the rapid speed increase of the steam turbine under a load rejection condition, and prohibiting activation of the steam turbine over-acceleration protection logic when the steam turbine generator set is in a grid-connected operation state, comprises:

[0013] If the actual speed of the steam turbine is greater than the first steam turbine over-acceleration protection logic effective speed threshold and is not greater than the second steam turbine over-acceleration protection logic effective speed threshold, obtaining the steam turbine speed acceleration;

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

[0015] If not, controlling 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, and the steam turbine over-acceleration protection does not operate;

[0016] If so, the steam turbine is controlled to prohibit the steam turbine over-acceleration protection logic from being activated when the steam turbine generator set is in a grid-connected operation state.

[0017] Optionally, the controlling of 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 suppress the rapid speed increase of the steam turbine under a load rejection condition, and prohibiting activation of the steam turbine over-acceleration protection logic when the steam turbine generator set is in a grid-connected operation state, comprises:

[0018] If the actual speed of the steam turbine is greater than the first steam turbine over-acceleration protection logic effective speed threshold and is not greater than the second steam turbine over-acceleration protection logic effective speed threshold, obtaining the steam turbine speed acceleration;

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

[0020] If not, controlling 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, controlling the steam turbine over-acceleration protection action, controlling all steam inlet regulating valves of the steam turbine regulating system to close, and cutting off the steam inlet to the steam turbine; when the steam turbine speed acceleration decreases to less than the steam turbine speed acceleration threshold, performing closed-loop control on the opening of the steam inlet regulating valve according to the steam turbine output power;

[0021] If so, the steam turbine is controlled to prohibit the turbine over-acceleration protection logic from being activated when the steam turbine generator set is in the grid-connected operation state, so that the total effective steam demand of the steam turbine remains unchanged, and the steam turbine regulating valve is controlled not to operate.

[0022] Optionally, the controlling of 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 suppress the rapid speed increase of the steam turbine under a load rejection condition, and prohibiting activation of the steam turbine over-acceleration protection logic when the steam turbine generator set is in a grid-connected operation state, comprises:

[0023] If the actual speed of the steam turbine is greater than the second steam turbine over-acceleration protection logic effective speed threshold and is not greater than the first steam turbine over-speed protection logic effective speed threshold, obtaining the steam turbine speed acceleration, wherein the second steam turbine over-acceleration protection logic effective speed threshold is greater than the first steam turbine over-acceleration protection logic effective speed threshold;

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

[0025] If not, controlling 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, and the steam turbine over-acceleration protection does not operate;

[0026] If so, controlling the steam turbine to prohibit the steam turbine over-acceleration protection logic from being activated when the steam turbine generator set is in a grid-connected operation state;

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

[0028] If not, controlling the steam turbine to enter the steam turbine over-acceleration protection logic when the steam turbine generator set is in a non-grid-connected operation state, and the steam turbine over-acceleration protection is actuated;

[0029] If so, the steam turbine is controlled to prohibit the steam turbine over-acceleration protection logic from being activated when the steam turbine generator set is in a grid-connected operation state.

[0030] Optionally, the controlling of 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 suppress the rapid speed increase of the steam turbine under a load rejection condition, and prohibiting activation of the steam turbine over-acceleration protection logic when the steam turbine generator set is in a grid-connected operation state, comprises:

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

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

[0033] If not, controlling 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, controlling the steam turbine over-acceleration protection action, controlling all steam inlet regulating valves of the steam turbine regulating system to close, and cutting off the steam inlet to the steam turbine; when the time for cutting off the steam inlet to the steam turbine reaches a second preset time period, when the steam turbine speed acceleration decreases to less than the steam turbine speed acceleration threshold, performing closed-loop control on the opening of the steam inlet regulating valve according to the steam turbine output power;

[0034] If so, the turbine over-acceleration protection logic is prohibited from being activated, the value of the effective steam demand parameter protection component is controlled to remain unchanged, and the opening of the steam inlet regulating valve is kept unchanged.

[0035] Optionally, the controlling of 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 suppress the rapid speed increase of the steam turbine under a load rejection condition, and prohibiting activation of the steam turbine over-acceleration protection logic when the steam turbine generator set is in a grid-connected operation state, comprises:

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

[0037] If not, when the turbine speed acceleration is not greater than the turbine speed acceleration threshold, the effective steam demand parameter and the steam inlet regulating valve are controlled to remain unchanged; when the turbine speed acceleration is greater than the turbine speed acceleration threshold, the turbine over-acceleration protection action is controlled, and if the time when the turbine speed acceleration is greater than the turbine speed acceleration threshold continues for a first preset time period, the turbine over-acceleration protection action is controlled to be maintained for a second preset time period;

[0038] If so, the turbine overacceleration protection logic is prohibited from being activated, and the turbine overspeed protection logic is activated. 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 for the first turbine overspeed protection logic to take effect, the opening of the steam inlet regulating valve is closed-loop controlled according to the turbine output power.

[0039] Optionally, the controlling of 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 suppress the rapid speed increase of the steam turbine under a load rejection condition, and prohibiting activation of the steam turbine over-acceleration protection logic when the steam turbine generator set is in a grid-connected operation state, comprises:

[0040] When the actual speed of the steam turbine is greater than the speed threshold at which the second steam turbine overspeed protection logic is effective, the effective steam demand parameter protection component is set to a set value, and it is determined whether the steam turbine generator set is in a grid-connected operation state;

[0041] If not, the turbine over-acceleration protection logic and the turbine over-speed protection logic are controlled to be enabled, and the turbine over-speed protection takes precedence over the turbine over-acceleration protection action. 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, thereby cutting off the steam inlet of the turbine. When the turbine speed drops to less than the speed threshold at which the second turbine over-speed protection logic takes effect, the opening of the steam inlet regulating valve is closed-loop controlled according to the turbine output power.

[0042] If so, the turbine overacceleration protection logic is prohibited from being activated, and the turbine overspeed protection logic is activated. 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 drops to less than the speed threshold for the first turbine overspeed protection logic to take effect, the opening of the steam inlet regulating valve is closed-loop controlled according to the turbine output power.

[0043] A steam turbine control device, comprising:

[0044] Speed ​​acquisition unit, used to obtain the actual speed of the steam turbine;

[0045] a judgment unit, configured to judge whether the actual speed of the steam turbine is greater than a first steam turbine over-acceleration protection logic effective speed threshold;

[0046] A control unit is used to control the steam turbine to activate the steam turbine super-acceleration protection logic when the steam turbine generator set is in a non-grid-connected operation state, so as to suppress the rapid speed increase of the steam turbine under load rejection conditions, and to prohibit the activation of the steam turbine super-acceleration protection logic when the steam turbine generator set is in a grid-connected operation state.

[0047] A computer storage medium stores at least one instruction, wherein the at least one instruction is executed by a processor to implement any steam turbine control method.

[0048] An electronic device, comprising: 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] From the above technical solution, it can be seen that the present invention discloses a steam turbine control method and related devices, which obtain the actual speed of the steam turbine. When the actual speed of the steam turbine is greater than the speed threshold for the effectiveness of the first steam turbine super-acceleration protection logic, the steam turbine is controlled to activate the steam turbine super-acceleration protection logic when the steam turbine generator set is in a non-grid-connected operation state, so as 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 set is in a grid-connected operation state. The present invention adds a grid-connected lockout condition to the steam turbine over-acceleration protection logic, that is, adds a judgment condition for whether the steam turbine generator set is grid-connected or non-grid-connected to the power grid. When the steam turbine generator set is in a non-grid-connected operating condition, the turbine over-acceleration protection logic is activated to suppress the rapid speed increase of the turbine under load rejection conditions, thereby achieving control of the turbine speed and avoiding overspeed tripping caused by excessive turbine speed acceleration. When the steam turbine generator set is in a grid-connected operating condition, the turbine over-acceleration protection logic is not activated to avoid frequent operation of the turbine regulating valve, thereby ensuring power grid safety and nuclear safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the disclosed drawings without any creative work.

[0053] Figure 1 A flow chart of a steam turbine control method disclosed in an embodiment of the present invention;

[0054] Figure 2This is a schematic structural diagram of a steam turbine control device disclosed in an embodiment of the present invention;

[0055] Figure 3 The figure is a schematic structural diagram of an electronic device disclosed in an embodiment of the present invention. DETAILED DESCRIPTION

[0056] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0057] When a steam turbine generator is connected to the grid, under conditions such as a proximal fault at the high-voltage busbar outlet or a bipolar lockout of the ultra-high voltage DC system, the turbine overacceleration protection logic is designed to prevent the turbine speed from exceeding 110% of the tripping speed by closing the turbine control valve. However, due to the overly conservative setting of the turbine overacceleration protection logic, the turbine control valve frequently opens and closes under these conditions, causing grid disturbances and, in severe conditions, even grid instability. Furthermore, the frequent opening and closing of the turbine control valve can trigger water level or pressure protection in the nuclear power unit's steam generators due to untimely coordination between the control valve and the bypass discharge valve, potentially creating shutdown risks and compromising nuclear safety. The turbine overacceleration protection logic, originally intended to protect the unit, does not fully protect the unit, but instead poses risks to both grid and nuclear safety.

[0058] Based on this, an embodiment of the present invention discloses a steam turbine control method and related devices, which obtain the actual speed of the steam turbine. When the actual speed of the steam turbine is greater than the speed threshold at which the first steam turbine over-acceleration protection logic takes effect, 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 suppress the rapid speed increase of the steam turbine under load rejection conditions, 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 lockout condition to the steam turbine over-acceleration protection logic, that is, adds a judgment condition for whether the steam turbine generator set is grid-connected or non-grid-connected to the power grid. When the steam turbine generator set is in a non-grid-connected operating condition, the turbine over-acceleration protection logic is activated to suppress the rapid speed increase of the turbine under load rejection conditions, thereby achieving control of the turbine speed and avoiding overspeed tripping caused by excessive turbine speed acceleration. When the steam turbine generator set is in a grid-connected operating condition, the turbine over-acceleration protection logic is not activated to avoid frequent operation of the turbine regulating valve, thereby ensuring 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:

[0060] The thresholds involved in this application mainly include: A (speed threshold for the first turbine overacceleration protection logic to take effect), B (speed threshold for the second turbine overacceleration protection logic to take effect), C (speed threshold for the first turbine overspeed protection logic to take effect), D (speed threshold for the second turbine overspeed protection logic to take effect), and X (turbine speed acceleration threshold).

[0061] The values ​​of each threshold are determined as follows:

[0062] (1) The speed threshold at which the over-acceleration protection logic of the first steam turbine takes effect is represented by A.

[0063] To prevent frequent activation of the turbine over-acceleration protection, the turbine over-acceleration protection logic should be set to ensure that it is triggered when the actual turbine speed is greater than A but not greater than B, and not triggered when the actual speed is greater than B but not greater than C. In other words, the turbine speed should not reach B while the acceleration rate is maintained for a preset time period (e.g., 0.1s). Therefore, the value of A should be less than (BX × 0.1s).

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

[0065] (2) The speed threshold at which the over-acceleration protection logic of the second steam turbine takes effect is represented by B.

[0066] The turbine over-acceleration protection logic is activated only when the turbine generator set is disconnected from the grid (i.e., the turbine generator set is in a non-grid-connected operating state). At this time, the turbine over-speed protection logic activates at a speed threshold of D. Therefore, the turbine over-acceleration protection logic only activates when the turbine speed reaches B and the speed acceleration reaches X for a preset time period (e.g., 0.1s). To prevent the turbine from activating when the actual turbine speed is greater than B but not greater than D, this application sets the value of B to D minus the turbine speed rise value when the turbine acceleration is X.

[0067] Since the value of X is typically the acceleration value when the turbine is at 50% rated load rejection, to ensure that the turbine speed does not reach D when the turbine is at over 50% rated load rejection, an acceleration value of 2X is used in the calculation. Therefore, the speed increase is equal to the turbine speed acceleration 2X multiplied by the acceleration maintenance time t. The acceleration maintenance time t is equal to the logic setting maintenance time plus the system delay time plus the average oil motor stroke closing time of the turbine plus the cylinder volume time. Based on these calculations, the value of B is obtained.

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

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

[0070] Under grid-connected steam turbine generator set conditions, the turbine overspeed protection logic activation speed threshold is adjusted from D to C, and there are no acceleration protection criteria. Therefore, C should be able to ensure that under large acceleration (exceeding X), the turbine throttle valve closed to ensure that the turbine speed does not exceed 110% of the overspeed protection trip value. (If the turbine speed exceeds this value, excessive centrifugal stress will cause damage to important equipment such as turbine rotor blade breakage and rotor shaft breakage.) This process actually calculates the maximum take-off speed of the turbine under rated load rejection conditions at different initial speeds.

[0071] To ensure that the calculation is as conservative and accurate as possible, in actual application, the maximum soaring speed of the turbine during no-load rejection during the commissioning of the steam turbine generator set can be used, and the contribution of the abnormal working condition of the extraction steam check valve to the soaring speed of the turbine can be superimposed (the energy generated by the abnormal extraction steam check valve is conservatively taken to be 1.4 times the energy during normal no-load rejection).

[0072] Based on commissioning test data and the energy conservation method, the maximum turbine speed at different initial velocities was calculated. The initial speed at which the maximum turbine speed under abnormal extraction check valve operation does not exceed 110% was taken as the maximum value of C. Furthermore, to minimize the number of turbine control valve actuations, the value of C was calculated using the energy conservation method.

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

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

[0075] Considering that the turbine overspeed shutdown protection setting is generally set to 110% of the rated turbine speed, the value of the speed threshold D for the second turbine overspeed protection logic to take effect should ensure that when the turbine speed reaches D but the acceleration does not exceed the turbine speed acceleration threshold X, the turbine speed will not overspeed trip (otherwise the turbine overacceleration protection logic will be activated).

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

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

[0078] (5) Turbine speed acceleration threshold, represented by X.

[0079] In order to ensure that the turbine speed can be quickly stabilized under the turbine load rejection condition and avoid excessive turbine speed acceleration and overspeed tripping, the acceleration when the turbine is thrown from rated load to 50% of the rated load is generally taken as the speed acceleration threshold for over-acceleration protection. The specific calculation method is:

[0080] A) Calculate the inertia time constant T of the steam turbine generator set based on the turbine's moment of inertia, rated speed, and rated capacity of the generator;

[0081] B) Based on the inertia time constant, calculate the speed acceleration a of the turbine under rated load rejection and no-load condition by T=60n / a (where n is the rated speed of the turbine);

[0082] C) According to (in It is the load shedding amount of the unit from the rated power load platform. is the load rejection of the steam turbine generator set from rated load to no-load), calculate the turbine speed acceleration when the turbine is rejected by 50% of the rated load as X.

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

[0084] See also Figure 1The present invention discloses a flow chart of a steam turbine control method. This method is applied to a GRE (Governor and Regulating Equipment) system. The GRE adjusts the opening of the steam turbine's steam inlet valve to achieve closed-loop control of parameters such as unit power, frequency, and pressure, while protecting the equipment from thermal stress and mechanical damage. The system's core modules include an electronic control cabinet, a human-machine interface (operator station, engineer station), and actuators (such as high-pressure and low-pressure regulating valves). The electronic control cabinet includes a DPU (Data Processing Unit) and I / O cards.

[0085] Steam turbine control methods include:

[0086] Step S101: Acquire the actual speed of the steam turbine.

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

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

[0089] Usually, when the steam turbine generator set is in grid-connected or non-grid-connected operation, when the turbine speed exceeds the turbine speed threshold and the turbine speed rises rapidly to exceed the acceleration threshold, the turbine over-acceleration protection logic is executed to reduce the turbine speed to prevent the turbine speed from exceeding the unit trip speed.

[0090] The first steam turbine over-acceleration protection logic effective speed threshold A can be used as the minimum limit for determining whether the steam turbine over-acceleration protection logic is put into operation. When the actual steam turbine speed is not greater than the first steam turbine over-acceleration protection logic effective speed threshold, it indicates that the steam turbine speed will not exceed the steam turbine speed threshold and the steam turbine speed will not rise rapidly to exceed the acceleration threshold. As a result, the steam turbine speed will not exceed the unit trip speed. At this time, the steam turbine over-acceleration protection logic is controlled to prohibit input. At the same time, the steam turbine overspeed protection logic also needs to be controlled to prohibit input.

[0091] On the contrary, when the actual speed of the steam turbine is greater than the speed threshold for the first steam turbine over-acceleration protection logic to take effect, in order to avoid the situation where the steam turbine speed exceeds the unit trip speed, it is necessary to further determine whether to activate the steam turbine over-acceleration protection logic.

[0092] It should be noted that, in actual application, it is necessary to first input the steam turbine over-acceleration protection logic, and then further determine whether to execute the steam turbine over-acceleration protection logic, that is, whether the steam turbine over-acceleration protection is activated.

[0093] Step S103: 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 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 steam turbine generator set is in a grid-connected operation state.

[0094] Typically, to ensure that the turbine is protected from major accidents when the grid frequency rises abnormally to above 51.5Hz, the turbine generator set will be disconnected from the grid. At this time, when the turbine generator set is in a non-grid-connected operating state, the present application can inhibit the rapid speed increase of the turbine under load shedding conditions by activating the turbine over-acceleration protection logic, so that the turbine speed can be controlled to below 110% of the trip speed (if the speed exceeds this value, the excessive centrifugal stress will cause damage to important equipment such as turbine rotor blade breakage and rotor shaft breakage), thereby avoiding overspeed tripping caused by excessive turbine speed acceleration. The present application prohibits the activation of the turbine over-acceleration protection logic when the turbine generator set is in a grid-connected operating state that may endanger grid safety and nuclear safety, thereby avoiding frequent operation of the turbine regulating valve.

[0095] In summary, the present invention discloses a steam turbine control method that obtains the actual turbine speed. When the actual turbine speed is greater than the first turbine over-acceleration protection logic activation speed threshold, the method controls the turbine to activate the turbine over-acceleration protection logic when the turbine generator set is in a non-grid-connected operating state, thereby suppressing the rapid speed increase of the turbine under load rejection conditions. Furthermore, the method prohibits activation of the turbine over-acceleration protection logic when the turbine generator set is in a grid-connected operating state. The present invention adds a grid-connected lockout condition to the turbine over-acceleration protection logic, that is, a determination condition for whether the turbine generator set is grid-connected or non-grid-connected to the power grid. This allows the turbine over-acceleration protection logic to be activated when the turbine generator set is in a non-grid-connected operating state, thereby suppressing the rapid speed increase of the turbine under load rejection conditions and achieving turbine speed control, thereby avoiding excessive turbine speed acceleration and overspeed tripping. Furthermore, the turbine over-acceleration protection logic is not activated when the turbine generator set is in a grid-connected operating state, thereby avoiding frequent actuation of the turbine regulating valve and ensuring power grid and nuclear safety.

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

[0097] If the actual speed of the steam turbine is greater than the first steam turbine over-acceleration protection logic effective speed threshold and is not greater than the second steam turbine over-acceleration protection logic effective speed threshold, obtaining the steam turbine speed acceleration;

[0098] If the turbine speed acceleration is not greater than the turbine speed acceleration threshold, determining whether the turbine generator set is in a grid-connected operation state;

[0099] If not, controlling 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, and the steam turbine over-acceleration protection does not operate;

[0100] If so, the steam turbine is controlled to prohibit the steam turbine over-acceleration protection logic from being activated when the steam turbine generator set is in a grid-connected operation state.

[0101] When the GRE system detects that A is less than the actual turbine speed and less than or equal to B, the GRE system also monitors the turbine speed acceleration. If the turbine speed acceleration is less than or equal to X, when the turbine generator set is in a non-grid-connected operation state, only the turbine is controlled to activate the turbine over-acceleration protection logic to suppress the rapid speed increase of the turbine under load rejection conditions, and the turbine over-acceleration protection does not operate. If the turbine speed acceleration is less than or equal to X, when the turbine generator set is in a grid-connected operation state, the turbine over-acceleration protection logic is not activated to avoid frequent operation of the turbine control valve, and the turbine over-acceleration protection will not operate at this time.

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

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

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

[0105] If not, controlling 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, controlling the steam turbine over-acceleration protection action, controlling all steam inlet regulating valves of the steam turbine regulating system to close, and cutting off the steam inlet to the steam turbine; when the steam turbine speed acceleration decreases to less than the steam turbine speed acceleration threshold, performing closed-loop control on the opening of the steam inlet regulating valve according to the steam turbine output power;

[0106] If so, the steam turbine is controlled to prohibit the turbine over-acceleration protection logic from being activated when the steam turbine generator set is in the grid-connected operation state, so that the total effective steam demand of the steam turbine remains unchanged, and the steam turbine regulating valve is controlled not to operate.

[0107] When the GRE system detects that A < actual turbine speed ≤ B, it simultaneously monitors the turbine speed acceleration. If the turbine speed acceleration exceeds X, the effective steam demand parameter protection component is set to a set value, M (e.g., -150%). The system also monitors whether the turbine generator set is in grid-connected operation via the SAL (Speed ​​Acceleration Limiter) output port. If the turbine generator set is not in grid-connected operation, the system activates the turbine over-acceleration protection logic to suppress rapid turbine speed increase under load rejection conditions and control the turbine over-acceleration protection. Furthermore, the system controls the closing of all steam inlet control valves in the turbine control system by subtracting the set value, M (-150%), of the effective steam demand parameter protection component from the total effective steam demand parameter of the turbine control system, thus cutting off steam flow to the turbine. When the turbine speed acceleration drops below the turbine speed acceleration threshold, closed-loop control of the steam inlet control valve opening is implemented based on the turbine output power. When the steam turbine generator set is in grid-connected operation, the steam turbine is controlled not to activate the turbine over-acceleration protection logic, so that the total effective steam demand of the steam turbine remains unchanged, and the steam turbine regulating valve is controlled not to operate.

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

[0109] If the actual speed of the steam turbine is greater than the second steam turbine over-acceleration protection logic effective speed threshold and is not greater than the first steam turbine over-speed protection logic effective speed threshold, obtaining the steam turbine speed acceleration, wherein the second steam turbine over-acceleration protection logic effective speed threshold is greater than the first steam turbine over-speed protection logic effective speed threshold;

[0110] If the turbine speed acceleration is not greater than the turbine speed acceleration threshold, determining whether the turbine generator set is in a grid-connected operation state;

[0111] If not, controlling 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, and the steam turbine over-acceleration protection does not operate;

[0112] If so, the steam turbine is controlled to prohibit the steam turbine over-acceleration protection logic from being activated when the steam turbine generator set is in a grid-connected operation state.

[0113] If the turbine speed acceleration is greater than the turbine speed acceleration threshold, and the duration of the turbine speed acceleration being greater than the turbine speed acceleration threshold is less than a first preset time period, determining whether the turbine generator set is in a grid-connected operation state;

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

[0115] If so, the steam turbine is controlled to prohibit the steam turbine over-acceleration protection logic from being activated when the steam turbine generator set is in a grid-connected operation state.

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

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

[0118] If the actual speed of the steam turbine is greater than the second steam turbine over-acceleration protection logic effective speed threshold and is not greater than the first steam turbine over-speed protection logic effective speed threshold, obtaining the steam turbine speed acceleration, wherein the second steam turbine over-acceleration protection logic effective speed threshold is greater than the first steam turbine over-speed protection logic effective speed threshold;

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

[0120] If not, controlling 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, controlling the steam turbine over-acceleration protection action, controlling all steam inlet regulating valves of the steam turbine regulating system to close, and cutting off the steam inlet to the steam turbine; when the time for cutting off the steam inlet to the steam turbine reaches a second preset time period, when the steam turbine speed acceleration decreases to less than the steam turbine speed acceleration threshold, performing closed-loop control on the opening of the steam inlet regulating valve according to the steam turbine output power;

[0121] If so, the turbine over-acceleration protection logic is prohibited from being activated, the value of the effective steam demand parameter protection component is controlled to remain unchanged, and the opening of the steam inlet regulating valve is kept unchanged.

[0122] When the GRE system detects that B is less than the actual turbine speed and less than or equal to C, it simultaneously monitors the turbine speed acceleration. If the turbine speed acceleration exceeds X for a duration of at least a first preset time period (e.g., 0.1s), the effective steam demand parameter protection component is set to a set value, M (e.g., -150%). Simultaneously, the SAL output port monitors whether the unit is in grid-connected operation. If the turbine generator set is not in grid-connected operation, the turbine over-acceleration protection logic is activated to prevent the turbine from rapidly accelerating under load rejection conditions. The turbine over-acceleration protection is activated, closing all steam inlet control valves in the turbine control system and shutting off steam flow to the turbine. When the turbine steam shutoff duration reaches a second preset time period (e.g., 0.5s) and the turbine speed acceleration decreases to less than X, closed-loop control of the steam inlet control valve opening is implemented based on the turbine output power. When the steam turbine generator set is in grid-connected operation, the turbine over-acceleration protection logic is not activated to avoid frequent operation of the turbine control valve, and the value of the effective steam demand parameter protection component is controlled to remain unchanged, and the opening of the steam inlet control valve remains unchanged.

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

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

[0125] If not, when the turbine speed acceleration is not greater than the turbine speed acceleration threshold, the effective steam demand parameter and the steam inlet regulating valve are controlled to remain unchanged; when the turbine speed acceleration is greater than the turbine speed acceleration threshold, the turbine over-acceleration protection action is controlled, and if the time when the turbine speed acceleration is greater than the turbine speed acceleration threshold continues for a first preset time period, the turbine over-acceleration protection action is controlled to be maintained for a second preset time period;

[0126] If so, the turbine overacceleration protection logic is prohibited from being activated, and the turbine overspeed protection logic is activated. 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 for the first turbine overspeed protection logic to take effect, 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 and less than or equal to D, the effective steam demand parameter protection component is set to a set value, M (e.g., -150%). Simultaneously, the SAL output port monitors whether the unit is in grid-connected operation. When the turbine generator set is not in grid-connected operation, and the turbine speed acceleration is ≤ X, the effective steam demand parameter and the steam inlet control valve remain unchanged. When the turbine speed acceleration is greater than X, the turbine overacceleration protection is activated. If the turbine speed acceleration exceeds X for a first preset time period (e.g., 0.1 seconds), the turbine overacceleration protection is activated for a second preset time period. When the turbine generator set is in grid-connected operation, the turbine overacceleration protection logic is deactivated and the turbine overspeed protection logic is activated. The difference between the effective steam demand parameter and the effective steam demand parameter protection component is output via the dual-path selection unit. All steam inlet control valves in the turbine control system are closed, cutting off steam inflow to the 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 is less than the actual speed of the steam turbine and less than or equal to 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, the turbine over-acceleration protection logic and the turbine over-speed protection logic are controlled to be enabled, and the turbine over-speed protection takes precedence over the turbine over-acceleration protection action. 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, thereby cutting off the steam inlet of the turbine. When the turbine speed drops to less than the speed threshold at which the second turbine over-speed protection logic takes effect, the opening of the steam inlet regulating valve is closed-loop controlled according to the turbine output power.

[0132] If so, the turbine overacceleration protection logic is prohibited from being activated, and the turbine overspeed protection logic is activated, the difference between the total effective steam demand parameter and the effective steam demand parameter protection component is output, and all the steam inlet regulating valves of the turbine control system are controlled to be closed, thereby cutting off the steam inlet of the turbine; when the turbine speed drops to less than the speed threshold at which the first turbine overspeed protection logic takes effect, the opening of the steam inlet regulating valve is closed-loop controlled according to the turbine output power.

[0133] When the GRE system detects that the actual turbine speed is greater than D, the effective steam demand parameter protection component is set to the set value M. Simultaneously, the SAL output port monitors whether the unit is in grid-connected operation. When the turbine generator set is not in grid-connected operation, both the turbine overacceleration protection logic and the turbine overspeed protection logic are activated, with the turbine overspeed protection taking precedence over the turbine overacceleration protection. By outputting the difference between the total effective steam demand parameter and the effective steam demand parameter protection component, all steam inlet control valves in the turbine control system are closed, cutting off steam flow to the turbine. When the turbine speed drops below D, closed-loop control of the steam inlet control valve opening is implemented based on the turbine output power. When the turbine generator set is in grid-connected operation, the turbine overacceleration protection logic is disabled and the turbine overspeed protection logic is activated. By outputting the difference between the total effective steam demand parameter and the effective steam demand parameter protection component, all steam inlet control valves in the turbine control system are closed, cutting off steam flow to the 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.

[0134] In summary, the present invention adds conditions for determining whether the turbine generator set is connected to or not connected to the power grid. This prevents the turbine overacceleration protection logic from being activated under grid-connected operating conditions that could endanger power grid and nuclear safety, thereby avoiding frequent actuation of the turbine control valve. Furthermore, to ensure that the turbine speed is controlled below the trip speed when the turbine generator set is not connected to the power grid in a major accident condition where the power grid frequency abnormally rises to above 51.5 Hz (if the turbine speed exceeds the trip speed, excessive centrifugal stress may cause damage to important equipment such as turbine rotor blade breakage and rotor shaft breakage), the second turbine overspeed protection logic activation speed threshold D (e.g., a value of D of 107% of the rated turbine speed) is moved forward to the safe first turbine overspeed protection logic activation speed threshold C (e.g., a value of C of 103% of the rated turbine speed). This prevents frequent actuation of the turbine control valve, ensuring power grid and nuclear safety while also preventing damage to important equipment under severe power grid conditions.

[0135] It should be noted that 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 prevent grid instability under short-circuit grid faults or bipolar blocking conditions of UHVDC transmission lines, avoid large-scale regional power outages, and reduce direct economic losses (estimated using the power generation ratio method, assuming that the units are started up within 8 hours after the power outage) = power shortage (kWh) × power generation ratio (yuan / kWh) = 572 million kWh × 9.3 yuan / kWh = 5.3196 billion yuan.

[0137] 2. The present invention can effectively prevent nuclear power units from tripping due to over-acceleration protection logic, reducing direct power generation revenue losses (assuming the units complete criticality and startup within 48 hours after shutdown) = 8.45 million yuan / unit-day × 6 units × 48 hours ÷ 24 hours = 101.4 million yuan.

[0138] 3. The total economic benefit created by this invention = avoided regional power outage losses + power generation revenue losses due to shutdown = 5.3196 billion yuan + 101.4 million yuan = 5.4210 billion yuan.

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

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

[0141] The speed acquisition unit 201 is used to acquire the actual speed of the steam turbine.

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

[0143] The judgment unit 202 is used to judge whether the actual speed of the steam turbine is greater than the first steam turbine over-acceleration protection logic effective speed threshold.

[0144] It should be noted that, in actual application, it is necessary to first input the steam turbine over-acceleration protection logic, and then further determine whether to execute the steam turbine over-acceleration protection logic, that is, whether the steam turbine over-acceleration protection is activated.

[0145] The control unit 203 is used to control the steam turbine to activate the turbine super-acceleration protection logic when the steam turbine generator set is in a non-grid-connected operation state, so as to suppress the rapid speed increase of the steam turbine under load rejection conditions, and to prohibit the activation of the turbine super-acceleration protection logic when the steam turbine generator set is in a grid-connected operation state when the judgment unit judges as yes.

[0146] Typically, to ensure that the turbine is protected from major accidents when the grid frequency rises abnormally to above 51.5Hz, the turbine generator set will be disconnected from the grid. At this time, when the turbine generator set is in a non-grid-connected operating state, the present application can inhibit the rapid speed increase of the turbine under load shedding conditions by activating the turbine over-acceleration protection logic, so that the turbine speed can be controlled to below 110% of the trip speed (if the speed exceeds this value, the excessive centrifugal stress will cause damage to important equipment such as turbine rotor blade breakage and rotor shaft breakage), thereby avoiding overspeed tripping caused by excessive turbine speed acceleration. The present application prohibits the activation of the turbine over-acceleration protection logic when the turbine generator set is in a grid-connected operating state that may endanger grid safety and nuclear safety, thereby avoiding frequent operation of the turbine regulating valve.

[0147] In summary, the present invention discloses a steam turbine control device that obtains the actual turbine speed. When the actual turbine speed is greater than the first turbine over-acceleration protection logic activation speed threshold, the device controls the turbine to activate the turbine over-acceleration protection logic when the turbine generator set is in a non-grid-connected operating state, thereby suppressing the rapid speed increase of the turbine under load rejection conditions. Furthermore, the device prohibits activation of the turbine over-acceleration protection logic when the turbine generator set is in a grid-connected operating state. The present invention adds a grid-connected lockout condition to the turbine over-acceleration protection logic, that is, a condition for determining whether the turbine generator set is grid-connected or non-grid-connected to the power grid. This allows the turbine over-acceleration protection logic to be activated when the turbine generator set is in a non-grid-connected operating state, thereby suppressing the rapid speed increase of the turbine under load rejection conditions and achieving turbine speed control, thereby preventing excessive turbine speed acceleration from causing an overspeed trip. Furthermore, the turbine over-acceleration protection logic is not activated when the turbine generator set is in a grid-connected operating state, thereby preventing frequent actuation of the turbine regulating valve and ensuring power grid and nuclear safety.

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

[0149] The disabling unit is used to control the turbine overacceleration protection logic and the turbine overspeed protection logic to be prohibited from being put into operation if the actual speed of the turbine is not greater than the speed threshold at which the first turbine overacceleration protection logic is effective.

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

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

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

[0153] If not, controlling 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, and the steam turbine over-acceleration protection does not operate;

[0154] If so, the steam turbine is controlled to prohibit the steam turbine over-acceleration protection logic from being activated when the steam turbine generator set is in a grid-connected operation state.

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

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

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

[0158] If not, controlling 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, controlling the steam turbine over-acceleration protection action, controlling all steam inlet regulating valves of the steam turbine regulating system to close, and cutting off the steam inlet to the steam turbine; when the steam turbine speed acceleration decreases to less than the steam turbine speed acceleration threshold, performing closed-loop control on the opening of the steam inlet regulating valve according to the steam turbine output power;

[0159] If so, the steam turbine is controlled to prohibit the turbine over-acceleration protection logic from being activated when the steam turbine generator set is in the grid-connected operation state, so that the total effective steam demand of the steam turbine remains unchanged, and the steam turbine regulating valve is controlled not to operate.

[0160] In one embodiment, the control unit 203 may be specifically configured to:

[0161] If the actual speed of the steam turbine is greater than the second steam turbine over-acceleration protection logic effective speed threshold and is not greater than the first steam turbine over-speed protection logic effective speed threshold, obtaining the steam turbine speed acceleration, wherein the second steam turbine over-acceleration protection logic effective speed threshold is less than the first steam turbine over-speed protection logic effective speed threshold;

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

[0163] If not, controlling 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, and the steam turbine over-acceleration protection does not operate;

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

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

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

[0167] If so, the steam turbine is controlled to prohibit the steam turbine over-acceleration protection logic from being activated when the steam turbine generator set is in a grid-connected operation state.

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

[0169] If the actual speed of the steam turbine is greater than the second steam turbine over-acceleration protection logic effective speed threshold and is not greater than the first steam turbine over-speed protection logic effective speed threshold, obtaining the steam turbine speed acceleration, wherein the second steam turbine over-acceleration protection logic effective speed threshold is less than the first steam turbine over-speed protection logic effective speed threshold;

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

[0171] If not, controlling 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, controlling the steam turbine over-acceleration protection action, controlling all steam inlet regulating valves of the steam turbine regulating system to close, and cutting off the steam inlet to the steam turbine; when the time for cutting off the steam inlet to the steam turbine reaches a second preset time period, when the steam turbine speed acceleration decreases to less than the steam turbine speed acceleration threshold, performing closed-loop control on the opening of the steam inlet regulating valve according to the steam turbine output power;

[0172] If so, the turbine over-acceleration protection logic is prohibited from being activated, the value of the effective steam demand parameter protection component is controlled to remain unchanged, and the opening of the steam inlet regulating valve is kept unchanged.

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

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

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

[0176] If so, the turbine overacceleration protection logic is prohibited from being activated, and the turbine overspeed protection logic is activated. The difference between the total effective steam demand parameter and the effective steam demand parameter protection component is output by the dual-path selection unit to control all the steam inlet regulating valves of the turbine control system to be closed, and the turbine steam inlet is cut off; when the turbine speed drops to less than the speed threshold for the first turbine overspeed protection logic to take effect, the opening of the steam inlet regulating valve is closed-loop controlled according to the turbine output power.

[0177] In one embodiment, the control unit 203 may be specifically configured to:

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

[0179] If not, the turbine over-acceleration protection logic and the turbine over-speed protection logic are controlled to be enabled, and the turbine over-speed protection takes precedence over the turbine over-acceleration protection action. The difference between the total effective steam demand parameter and the effective steam demand parameter protection component is output, and all the steam inlet regulating valves of the turbine control system are controlled to be closed to cut off the steam inlet of the turbine. When the turbine speed drops to less than the speed threshold for the second turbine over-speed protection logic to take effect, the opening of the steam inlet regulating valve is closed-loop controlled according to the turbine output power.

[0180] If so, the turbine overacceleration protection logic is prohibited from being activated, and the turbine overspeed protection logic is activated. 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 drops to less than the speed threshold for the first turbine overspeed protection logic to take effect, the opening of the steam inlet regulating valve is closed-loop controlled according to the turbine output power.

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

[0182] Corresponding to the above embodiment, the present invention further discloses a computer storage medium, which stores at least one instruction. When the at least one instruction is executed by a processor, the steps shown in the embodiment of the steam turbine control method are implemented.

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

[0184] The processor 1 and the memory 2 communicate with each other via a communication bus 3.

[0185] Processor 1, configured to execute at least one instruction;

[0186] Memory 2, used to store at least one instruction;

[0187] The processor 1 may be a central processing unit (CPU), an application 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 a non-volatile memory (non-volatile memory), such as at least one disk memory.

[0189] The processor executes at least one instruction to implement the steps shown in the embodiment of the steam turbine control method.

[0190] Finally, it should be noted that, in this document, relational terms such as first and second, etc., are used only 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 "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or device comprising the element.

[0191] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0192] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one 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. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A steam turbine control method, characterized in that: include: Get the actual speed of the turbine; Determining whether the actual speed of the steam turbine is greater than a first steam turbine over-acceleration protection logic effective speed threshold; If so, controlling 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 to suppress the rapid speed increase of the steam turbine under the load rejection condition, and prohibiting the activation of the steam turbine over-acceleration protection logic when the steam turbine generator set is in a grid-connected operation state, including: If the actual speed of the steam turbine is greater than the first steam turbine over-acceleration protection logic effective speed threshold and is not greater than the second steam turbine over-acceleration protection logic effective speed threshold, obtaining the steam turbine speed acceleration; If the turbine speed acceleration is not greater than the turbine speed acceleration threshold, determining whether the turbine generator set is in a grid-connected operation state; If not, controlling 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, and the steam turbine over-acceleration protection does not operate; If so, the steam turbine is controlled to prohibit the steam turbine over-acceleration protection logic from being activated when the steam turbine generator set is in a grid-connected operation state.

2. The steam turbine control method according to claim 1, characterized in that: Also includes: If the actual speed of the steam turbine is not greater than the speed threshold for the effectiveness of the first steam turbine over-acceleration protection logic, both the steam turbine over-acceleration protection logic and the steam turbine overspeed protection logic are prohibited from being put into operation.

3. The steam turbine control method according to claim 1 or 2, characterized in that: The control of 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 to suppress the rapid speed increase of the steam turbine under a load rejection condition, and prohibiting the activation of the steam turbine over-acceleration protection logic when the steam turbine generator set is in a grid-connected operation state, further includes: If the actual speed of the steam turbine is greater than the first steam turbine over-acceleration protection logic effective speed threshold and is not greater than the second steam turbine over-acceleration protection logic effective speed threshold, obtaining the steam turbine speed acceleration; If the turbine speed acceleration is greater than the turbine speed acceleration threshold, the effective steam demand parameter protection component is set to a set value, and it is determined whether the turbine generator set is in a grid-connected operation state; If not, controlling 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, controlling the steam turbine over-acceleration protection action, controlling all steam inlet regulating valves of the steam turbine regulating system to close, and cutting off the steam inlet to the steam turbine; when the steam turbine speed acceleration decreases to less than the steam turbine speed acceleration threshold, performing closed-loop control on the opening of the steam inlet regulating valve according to the steam turbine output power; If so, the steam turbine is controlled to prohibit the turbine over-acceleration protection logic from being activated when the steam turbine generator set is in the grid-connected operation state, so that the total effective steam demand of the steam turbine remains unchanged, and the steam turbine regulating valve is controlled not to operate.

4. The steam turbine control method according to claim 1, wherein: The control of 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 to suppress the rapid speed increase of the steam turbine under a load rejection condition, and prohibiting the activation of the steam turbine over-acceleration protection logic when the steam turbine generator set is in a grid-connected operation state, further includes: If the actual speed of the steam turbine is greater than the second steam turbine over-acceleration protection logic effective speed threshold and is not greater than the first steam turbine over-speed protection logic effective speed threshold, obtaining the steam turbine speed acceleration, wherein the second steam turbine over-acceleration protection logic effective speed threshold is greater than the first steam turbine over-acceleration protection logic effective speed threshold; If the turbine speed acceleration is not greater than the turbine speed acceleration threshold, determining whether the turbine generator set is in a grid-connected operation state; If not, controlling 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, and the steam turbine over-acceleration protection does not operate; If so, controlling the steam turbine to prohibit the steam turbine over-acceleration protection logic from being activated when the steam turbine generator set is in a grid-connected operation state; If the turbine speed acceleration is greater than the turbine speed acceleration threshold, and the duration of the turbine speed acceleration being greater than the turbine speed acceleration threshold is less than a first preset time period, determining whether the turbine generator set is in a grid-connected operation state; If not, controlling the steam turbine to enter the steam turbine over-acceleration protection logic when the steam turbine generator set is in a non-grid-connected operation state, and the steam turbine over-acceleration protection is actuated; If so, the steam turbine is controlled to prohibit the steam turbine over-acceleration protection logic from being activated when the steam turbine generator set is in a grid-connected operation state.

5. The steam turbine control method according to claim 1 or 4, characterized in that: The control of 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 to suppress the rapid speed increase of the steam turbine under a load rejection condition, and prohibiting the activation of the steam turbine over-acceleration protection logic when the steam turbine generator set is in a grid-connected operation state, further includes: If the actual speed of the steam turbine is greater than the second steam turbine over-acceleration protection logic effective speed threshold and is not greater than the first steam turbine over-speed protection logic effective speed threshold, obtaining the steam turbine speed acceleration, wherein the second steam turbine over-acceleration protection logic effective speed threshold is greater than the first steam turbine over-acceleration protection logic effective speed threshold; If the turbine speed acceleration is greater than the turbine speed acceleration threshold and lasts for a first preset time period, setting the effective steam demand parameter protection component to a set value, and determining whether the turbine generator set is in a grid-connected operation state; If not, controlling 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, controlling the steam turbine over-acceleration protection action, controlling all steam inlet regulating valves of the steam turbine regulating system to close, and cutting off the steam inlet to the steam turbine; when the time for cutting off the steam inlet to the steam turbine reaches a second preset time period, when the steam turbine speed acceleration decreases to less than the steam turbine speed acceleration threshold, performing closed-loop control on the opening of the steam inlet regulating valve according to the steam turbine output power; If so, the turbine over-acceleration protection logic is prohibited from being activated, the value of the effective steam demand parameter protection component is controlled to remain unchanged, and the opening of the steam inlet regulating valve is kept unchanged.

6. The steam turbine control method according to claim 1, characterized in that: The control of 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 to suppress the rapid speed increase of the steam turbine under a load rejection condition, and prohibiting the activation of the steam turbine over-acceleration protection logic when the steam turbine generator set is in a grid-connected operation state, further includes: When the actual speed of the steam turbine is greater than the first steam turbine overspeed protection logic effective speed threshold and is not greater than the second steam turbine overspeed protection logic effective speed threshold, setting the effective steam demand parameter protection component to a set value, and determining whether the steam turbine generator set is in a grid-connected operation state, wherein the second steam turbine overspeed protection logic effective speed threshold is greater than the first steam turbine overspeed protection logic effective speed threshold; If not, when the turbine speed acceleration is not greater than the turbine speed acceleration threshold, the effective steam demand parameter and the steam inlet regulating valve are controlled to remain unchanged; when the turbine speed acceleration is greater than the turbine speed acceleration threshold, the turbine over-acceleration protection action is controlled, and if the time when the turbine speed acceleration is greater than the turbine speed acceleration threshold continues for a first preset time period, the turbine over-acceleration protection action is controlled to be maintained for a second preset time period; If so, the turbine overacceleration protection logic is prohibited from being activated, and the turbine overspeed protection logic is activated. 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 for the first turbine overspeed protection logic to take effect, the opening of the steam inlet regulating valve is closed-loop controlled according to the turbine output power.

7. The steam turbine control method according to claim 1 or 6, characterized in that: The control of 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 to suppress the rapid speed increase of the steam turbine under a load rejection condition, and prohibiting the activation of the steam turbine over-acceleration protection logic when the steam turbine generator set is in a grid-connected operation state, further includes: When the actual speed of the steam turbine is greater than the speed threshold at which the second steam turbine overspeed protection logic is effective, the effective steam demand parameter protection component is set to a set value, and it is determined whether the steam turbine generator set is in a grid-connected operation state; If not, the turbine over-acceleration protection logic and the turbine over-speed protection logic are controlled to be enabled, and the turbine over-speed protection takes precedence over the turbine over-acceleration protection action. 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, thereby cutting off the steam inlet of the turbine. When the turbine speed drops to less than the speed threshold at which the second turbine over-speed protection logic takes effect, the opening of the steam inlet regulating valve is closed-loop controlled according to the turbine output power. If so, the turbine overacceleration protection logic is prohibited from being activated, and the turbine overspeed protection logic is activated. 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 drops to less than the speed threshold for the first turbine overspeed protection logic to take effect, the opening of the steam inlet regulating valve is closed-loop controlled according to the turbine output power.

8. A steam turbine control device, characterized in that: include: Speed ​​acquisition unit, used to obtain the actual speed of the steam turbine; a judgment unit, configured to judge whether the actual speed of the steam turbine is greater than a first steam turbine over-acceleration protection logic effective speed threshold; a control unit configured to, if the judgment unit determines that the condition is yes, control the steam turbine to activate a steam turbine over-acceleration protection logic when the steam turbine generator set is in a non-grid-connected operation state, so as to suppress a rapid speed increase of the steam turbine under a load rejection condition, and prohibit activation of the steam turbine over-acceleration protection logic when the steam turbine generator set is in a grid-connected operation state; The control unit is specifically used for: If the actual speed of the steam turbine is greater than the first steam turbine over-acceleration protection logic effective speed threshold and is not greater than the second steam turbine over-acceleration protection logic effective speed threshold, obtaining the steam turbine speed acceleration; If the turbine speed acceleration is not greater than the turbine speed acceleration threshold, determining whether the turbine generator set is in a grid-connected operation state; If not, controlling 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, and the steam turbine over-acceleration protection does not operate; If so, the steam turbine is controlled to prohibit the steam turbine over-acceleration protection logic from being activated when the steam turbine generator set is in a grid-connected operation state.

9. 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 the processor, the steam turbine control method according to any one of claims 1 to 7 is implemented.

10. An electronic device, characterized in that: The electronic device includes: a memory and a processor; The memory is used to store at least one instruction; The processor is used to execute the at least one instruction to implement the steam turbine control method according to any one of claims 1 to 7.

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