Steam turbine hot start and rotation control method, rotation parameter control method and system

Abstract

The present application relates to a kind of steam turbine hot state start-up control method, rotation control method and system, comprising: using ATC system control unit speed by one-stage speed-up target speed Z1 Gradually speed up to the unit speed Z3 of no-load in the unit speed-up step, using parameter control system corrects unit speed-up rate and unit warm-up time, specifically, the parameter control system in the process of unit automatic rotation and speed-up, obtain several variable real-time values of the variable that influences unit rotation parameter, and calculate variable real-time value change rate, and then can in the process of unit rotation, using variable real-time value change rate, corrects unit rotation parameter, with flexible control unit operation, increase the accuracy and flexibility of unit rotation control advantage.

Description

Technical Field

[0001] This invention relates to the technical field of turbine start-up control for thermal power units, and in particular to a turbine hot start-up control method, a start-up parameter control method, and a system. Background Technology

[0002] Currently, most thermal power unit turbine start-up control systems still use manual control for turbine start-up. During the start-up process, it is necessary to determine whether to continue warming up or increasing speed based on factors such as the unit's expansion differential and the temperature difference between the upper and lower inner walls of the cylinder. This places high demands on the experience and technical skills of the operators. On the other hand, the turbine start-up requires a large amount of manual operation, and the numerous conditions for pre-start-up checks and confirmations increase the workload of operators, making it difficult to guarantee speed and accuracy. For example, CN 113090343A discloses a method for shortening the cold start time of a steam turbine by increasing the steam flow at different nodes to optimize the unit start-up process and thus shorten the start-up time. However, it does not involve flexibly controlling the unit's operation based on changes in unit operating conditions to increase the accuracy and flexibility of the turbine start-up control. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to overcome the defects in the prior art, thereby providing a steam turbine hot start-up control method, a start-up parameter control method and system.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A method for automatic start-up parameter correction of a back-pressure steam turbine during hot start-up includes:

[0006] S1: During the automatic start-up process of the unit, obtain the real-time values ​​of several variables that affect the start-up parameters of the unit, and calculate the rate of change of the real-time values ​​of the variables;

[0007] S2: Filter the maximum value of the real-time value change rate of the variable, and use it to calculate the correction amount of the real-time value change rate of the variable to the unit start-up parameters, and generate the first correction amount;

[0008] S3: Obtain the temperature of the lower half of the inner wall of the cylinder inlet chamber at the current moment when the unit's ATC is engaged, and use it to calculate the correction amount of the lower half of the inner wall of the cylinder inlet chamber to the unit's start-up parameters, and generate the second correction amount.

[0009] S4: Obtain the initial values ​​of the unit's start-up parameters;

[0010] S5: Calculate the corrected unit start-up parameters using the first correction amount, the second correction amount, and the initial values ​​of the unit start-up parameters.

[0011] Preferably, the unit start-up parameters include the unit start-up rate and the unit warm-up time;

[0012] The second correction includes the correction FF2 for the turbine's acceleration rate caused by the lower half inner wall temperature TT1 of the cylinder inlet chamber, which is calculated using the following formula:

[0013] FF2 = Max[FF20, 0];

[0014] FF20=K1×(TT1-TT_0-△T) / TT_0;

[0015] The second correction also includes a correction factor FF3 for the warm-up time of the unit based on the lower half inner wall temperature TT1 of the cylinder inlet chamber, which is calculated using the following formula:

[0016] FF3 = Max[FF30, 0];

[0017] FF30=K2×(TT1-TT_0-△T) / TT_0;

[0018] Where TT_0 is the set value of the lower half of the inner wall temperature of the cylinder inlet chamber when judging the hot state of the unit; △T is the temperature offset margin; K1 is the correction coefficient of the unit's start-up rate; K2 is the correction coefficient of the unit's start-up warm-up time.

[0019] Preferably, the first correction amount includes a correction amount FF1 for the rate of change of the real-time value of the variable on the unit's start-up rate, which is calculated using the following formula:

[0020] FF1 = K3 × Rate_v;

[0021] Among them, Rate_v is the maximum value of the real-time change rate of the variable affecting the unit's start-up rate;

[0022] The first correction also includes a correction FF4 for the rate of change of the real-time value of the variable on the unit's warm-up time, which is calculated using the following formula:

[0023] FF4 = Ti1 - K4 × Rate_t;

[0024] Where Ti1 is the maximum correction bias of the variable affecting the unit warm-up time on the unit warm-up time; K4 is the correction coefficient of the variable affecting the unit warm-up time on the unit warm-up time; and Rate_t is the maximum value of the real-time change rate of the variable affecting the unit warm-up time.

[0025] Preferably, the unit corrected start-up parameters include the unit corrected start-up rate Vi, which is calculated using the following formula:

[0026] Vi=Med[0.8×Vi0,Vi0-FF1+FF2,1.2×Vi0];

[0027] Where Vi0 is the initial value of the unit's initial acceleration rate;

[0028] The unit correction start-up parameters also include the unit correction warm-up time Ti, which is calculated using the following formula:

[0029] Ti=Med[0.7×Ti0,Ti0-FF3-FF4,Ti0];

[0030] Where Ti0 is the initial value of the unit's start-up and warm-up time.

[0031] A parameter control system adapted to the above-mentioned method for automatic start-up parameter correction of a back-pressure steam turbine during hot start-up includes:

[0032] The unit monitoring module is used to acquire real-time data of variables affecting the unit's start-up parameters, temperature data of the lower half of the cylinder inlet chamber at the moment the unit's ATC is activated, and initial value data of the unit's start-up parameters.

[0033] The data transmission module is used to call the real-time values ​​of the variables affecting the unit's start-up parameters, the temperature data of the lower half of the cylinder inlet chamber at the current moment when the unit's ATC is activated, and the initial value data of the unit's start-up parameters, and transmit them to the data processing module.

[0034] The data processing module is used to calculate the correction amount of the real-time value change rate of the variable affecting the unit's start-up parameters using the real-time value data of the variable, and generate a first correction amount;

[0035] The data processing module is used to use the temperature data of the lower half of the cylinder inlet chamber of the unit's ATC input at the current moment, calculate the correction amount of the temperature of the lower half of the cylinder inlet chamber to the unit's start-up parameters, and generate a second correction amount.

[0036] The data processing module is used to calculate the corrected unit start-up parameters using the initial value data of the unit start-up parameters, the first correction amount, and the second correction amount;

[0037] The control module is used to acquire the unit's corrected start-up parameters and control the unit's operation.

[0038] A back-pressure steam turbine hot start automatic start-up control method includes: in the unit speed-up step of controlling the unit speed to gradually increase from the first-stage target speed Z1 to the no-load speed Z3, the unit start-up rate and unit warm-up time are corrected using the back-pressure steam turbine hot start-up automatic start-up parameter correction method described above.

[0039] Preferably, the unit speed-up step includes:

[0040] The first-stage speed-up process includes controlling the unit to speed up to the first-stage target speed Z1 at a first-stage speed-up rate V1;

[0041] The second-stage acceleration step includes controlling the unit to accelerate from the first-stage target speed Z1 to the second-stage target speed Z2 at a second-stage acceleration rate V2.

[0042] The medium-speed warm-up process includes controlling the unit to run at a constant speed of the secondary target speed Z2 for warm-up.

[0043] The three-stage acceleration process includes: setting a critical speed zone between the secondary target speed Z2 and the no-load speed Z3, wherein the critical speed zone includes a minimum speed and a maximum speed; controlling the unit to accelerate from the secondary target speed Z2 to the minimum speed of the critical speed zone at a three-stage acceleration rate V3; controlling the unit to accelerate from the minimum speed of the critical speed zone to the maximum speed of the critical speed zone at a critical speed zone acceleration rate V31; and controlling the unit to accelerate from the maximum speed of the critical speed zone to the no-load speed Z3 at a three-stage acceleration rate V3.

[0044] The warm-up time of the first-stage acceleration rate V1, the second-stage acceleration rate V2, the third-stage acceleration rate V3, and the medium-speed warm-up step is corrected by the automatic stroke parameter correction method.

[0045] Preferably, during the second-stage speed-up step, it is determined whether the unit has an abnormal alarm signal. If so, the unit is controlled to perform the first alarm fault handling step.

[0046] During the medium-speed warm-up process, it is determined whether the unit has an abnormal alarm signal. If so, the unit is controlled to perform the second alarm fault handling step.

[0047] During the process of the control unit accelerating from the secondary target speed Z2 to the minimum speed in the critical speed range at a three-level acceleration rate V3, it is determined whether the unit has an abnormal alarm signal. If so, the control unit decelerates to the secondary target speed Z2.

[0048] During the process of the control unit accelerating from the maximum speed in the critical speed range to the no-load speed Z3 at the three-stage acceleration rate V3, if the current speed of the unit is greater than the three-stage intermediate speed Z31, it is determined whether the unit has an abnormal alarm signal. If so, the control unit performs the third alarm fault handling step.

[0049] Preferably, the first alarm fault handling step includes: determining whether the current speed of the unit is greater than the secondary intermediate speed Z21; if not, controlling the unit speed to decrease to the primary acceleration target speed Z1; if so, controlling the unit to decrease from the current speed to the low-speed warm-up speed Z4 at a fixed deceleration rate A, and after completing the low-speed warm-up at the low-speed warm-up speed Z4, accelerating to the secondary target speed Z2 at the secondary acceleration rate V2.

[0050] The second alarm fault handling steps include: controlling the unit to decelerate from the secondary target speed Z2 to the low-speed warm-up speed Z4 at the fixed deceleration rate A, and after completing the low-speed warm-up at the low-speed warm-up speed Z4, then accelerating to the secondary target speed Z2 at the secondary acceleration rate V2.

[0051] The warm-up time for low-speed warm-up is corrected by the automatic rev-up parameter correction method.

[0052] Preferably, the third alarm fault handling step includes:

[0053] The control unit decelerates from the current speed to the high-speed warm-up speed Z5 at a fixed deceleration rate A, and after completing the high-speed warm-up at the high-speed warm-up speed Z5, it accelerates to the no-load speed Z3 at a fixed acceleration rate B.

[0054] Compared with the prior art, the beneficial effects of the present invention are as follows: The back-pressure steam turbine hot start automatic start-up parameter correction method provided in the above technical solution performs real-time detection of variables affecting the unit's start-up parameters during the automatic start-up process. The real-time values ​​of the variables affecting the unit's start-up parameters are used to calculate the correction amount of the unit's start-up parameters, thereby directly calculating the corrected start-up rate and the corrected start-up warm-up time. This allows the unit to automatically adjust the unit's start-up parameters according to the unit's operating conditions, resulting in higher unit operating efficiency and reducing the occurrence of unit fault alarms.

[0055] The back-pressure steam turbine hot-state start-up automatic start-up control method provided in the above technical solution can use the above parameter correction method to control the unit during the start-up process. Based on the operating status and variables affecting the unit's start-up parameters, it adjusts the unit's acceleration rate and warm-up time, making the unit operation more consistent with the current operating status. This reduces the probability of the unit triggering a fault alarm signal. In addition, by using the ATC control system and the above parameter correction method to control the unit's operation, it can reduce errors and workload caused by personnel relying on work experience or technical judgment, improve the efficiency of the unit's acceleration process and the accuracy of anomaly judgment, reduce human intervention, alleviate the operational requirements of operators, increase the reliability and safety of the unit's start-up, and improve the unit's automation level. Attached Figure Description

[0056] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0057] Figure 1 This is a schematic diagram of a method for correcting the automatic start-up rate and warm-up time of a back-pressure steam turbine during hot start-up.

[0058] Figure 2 This is a schematic diagram of the unit's speed-up steps.

[0059] Figure 3 This is a schematic diagram illustrating the handling of Class I and Class II alarm faults.

[0060] Figure 4 This is a schematic diagram illustrating the handling of three types of alarm faults.

[0061] Figure 5 This is a schematic diagram of the initial operation steps of the unit. Detailed Implementation

[0062] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0063] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0064] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0065] like Figure 1 As shown, a method for automatic start-up parameter correction of a back-pressure steam turbine during hot start-up includes:

[0066] The first step is to acquire real-time values ​​of several variables affecting the unit's start-up parameters during the automatic start-up process, and calculate the rate of change of these real-time values. Specifically, the start-up rate and warm-up time are two important start-up parameters. The start-up rate controls the speed at which the unit accelerates, while the warm-up time controls the duration of the warm-up, thus preparing for the subsequent acceleration process. There are many variables that affect the turbine's start-up rate and warm-up time. Variables affecting the start-up rate include, but are not limited to: turbine vibration (shaft vibration, bearing vibration, etc.), cylinder expansion, temperature difference between the upper and lower cylinders, temperature difference between the inner and outer walls of the turbine, bearing metal, thrust bearing temperature, and temperature of the lower half of the cylinder intake chamber. Variables affecting the warm-up time include, but are not limited to: cylinder expansion difference, temperature difference between the upper and lower cylinders, and temperature of the lower half of the cylinder intake chamber. These factors should be considered when adjusting the turbine's start-up parameters, start-up rate, and warm-up time.

[0067] The second step involves selecting the maximum value of the real-time change rate of the variable and using it to calculate the correction amount of the real-time change rate of the variable to the unit's start-up parameters, thus generating the first correction amount. In this step, the variable with the greatest influence is identified, and then the first correction amount used to correct the corresponding start-up parameters is determined. That is, the first correction amount is an important parameter for correcting the unit's start-up rate and unit warm-up time.

[0068] The third step is to obtain the temperature of the lower half of the cylinder inlet chamber's inner wall at the moment the unit's ATC (Automatic Control Center) is engaged, and use this temperature to calculate the correction amount for the unit's start-up parameters, generating a second correction amount. Specifically, since the current temperature of the lower half of the cylinder inlet chamber's inner wall is recorded when the turbine is engaged by the ATC system, a higher temperature results in a shorter unit shutdown time and more uniform heating of the turbine's metal components. This allows for a faster turbine start-up acceleration and a reduced warm-up time at a constant turbine speed. Therefore, the second correction amount is also an important parameter for correcting the unit's start-up rate and warm-up time.

[0069] The fourth step is to obtain the initial values ​​of the unit's start-up parameters.

[0070] The fifth step involves calculating the corrected turbine start-up parameters using the first correction, the second correction, and the initial values ​​of the unit's start-up parameters. Specifically, since the unit correction should ideally not exceed 30% of the initial parameters, the turbine start-up rate should be limited to avoid over-correction that could affect the unit's normal start-up operation. Therefore, the final corrected turbine start-up parameters should be calculated by comprehensively considering the various first and second corrections, the initial values ​​of the unit's start-up parameters, and the relevant limiting ranges.

[0071] Using the above-mentioned technical solution, variables affecting the unit's start-up parameters are detected in real time during the automatic start-up process. The real-time values ​​of these variables are used to calculate the correction amount for the start-up parameters, which in turn allows for the direct calculation of the corrected start-up rate and the corrected start-up warm-up time. This enables the unit to automatically adjust its start-up parameters according to its operating conditions, resulting in higher operating efficiency and a reduction in unit fault alarms.

[0072] Furthermore, when using the above method to correct the unit's start-up rate, such as Figure 1 As shown, firstly, the real-time values ​​of the variables affecting the unit's start-up rate are obtained, and then the corresponding real-time value change rates Rate_v1, Rate_v2, Rate_v3...Rate_vn are calculated.

[0073] Then, the maximum value function is used to select the maximum value, Rate_v, which affects the rate of change of the real-time value of the variable affecting the unit's start-up rate. Specifically:

[0074] Rate_v=Max[Rate_v1,Rate_v2,Rate_v3,...,Rate_vn];

[0075] TT_n0 < (1-K30) When Alarm_n is active, Rate_vn = 0;

[0076] Where Rate_vn is the rate of change of the real-time measured value of the nth variable affecting the turbine's acceleration rate; TT_n0 is the real-time measured value of the nth variable affecting the turbine's acceleration rate; Alarm_n is the alarm fault setpoint of the nth variable affecting the turbine's acceleration rate; and K30 is the offset correction coefficient for the variable's alarm fault value; K30 can be taken as 0.4 to 0.6.

[0077] Then, the first correction amount is calculated using the maximum value of the rate of change of the variable affecting the unit's start-up rate, Rate_v. Specifically, the first correction amount is the correction amount FF1 of the rate of change of the variable's real-time value to the unit's start-up rate, and is calculated using the formula FF1=K3×Rate_v.

[0078] Then, using the temperature TT1 of the lower half of the cylinder inlet chamber's inner wall, the second correction amount is calculated. Specifically, the second correction amount is the correction FF2 of the lower half of the cylinder inlet chamber's inner wall temperature TT1 to the unit's acceleration rate. And using:

[0079] FF2 = Max[FF20, 0];

[0080] FF20=K1×(TT1-TT_0-△T) / TT_0;

[0081] These two formulas are used for calculation, where TT_0 is the set value of the lower half of the inner wall temperature of the cylinder inlet chamber when judging the hot state of the unit; △T is the temperature offset margin; K1 is the correction coefficient of the unit's acceleration rate; in one embodiment, TT_0 can be taken as 300℃, △T can be calculated using (10%~15%)×TT_0, and K1 can be taken as 20~40.

[0082] Then, the initial value Vi0 of the unit's start-up rate is obtained. The value of Vi0 is different in different start-up rate stages.

[0083] Finally, using the correction amount FF1 of the real-time change rate of the above variables to the unit's throttle acceleration rate, the correction amount FF2 of the lower half inner wall temperature TT1 of the cylinder inlet chamber to the unit's throttle acceleration rate, and the initial value Vi0 of the unit's throttle acceleration rate, the corrected unit throttle acceleration rate Vi is calculated. Specifically, it can be calculated using the formula: Vi=Med[0.8×Vi0,Vi0-FF1+FF2,1.2×Vi0].

[0084] Furthermore, when using the above method to correct the unit's warm-up time, such as Figure 1 As shown, firstly, the real-time values ​​of the variables affecting the unit's warm-up time are obtained, specifically the turbine cylinder expansion difference and the temperature difference between the upper and lower turbine cylinders, and the corresponding real-time value change rates Rate_t1 and Rate_t2 are calculated.

[0085] Then, the maximum value function is used to select the maximum value, Rate_t, which affects the rate of change of the real-time value of the unit's warm-up time variable. Specifically:

[0086] Rate_t=Max[Rate_t1,Rate_t2].

[0087] Then, the first correction amount is calculated using the maximum value of the rate of change of the real-time value of the unit warm-up time variable, Rate_t. The first correction amount is specifically the correction amount FF4 of the rate of change of the real-time value of the variable on the unit warm-up time, and is calculated using the formula FF4=Ti1-K4×Rate_t, where Ti1 is the maximum correction bias of the variable affecting the unit warm-up time; K4 is the correction coefficient of the variable affecting the unit warm-up time. In one embodiment, Ti1 can be 2 to 3, and K4 can be 35 to 50.

[0088] Then, using the temperature TT1 of the lower half of the cylinder inlet chamber's inner wall, the second correction amount is calculated. Specifically, the second correction amount is the correction FF3 made by the temperature TT1 of the lower half of the cylinder inlet chamber's inner wall to the unit's warm-up time. This correction is then applied using:

[0089] FF3 = Max[FF30, 0];

[0090] FF30=K2×(TT1-TT_0-△T) / TT_0;

[0091] These two formulas are used for calculation, where TT_0 is the set value of the lower half of the inner wall temperature of the cylinder inlet chamber when judging the hot state of the unit; △T is the temperature offset margin; K2 is the correction coefficient for the unit's start-up and warm-up time; in one embodiment, TT_0 can be taken as 300℃, △T can be calculated using (10%~15%)×TT_0, and K2 can be taken as 2~4.

[0092] Then, the initial value Ti0 of the unit's start-up and warm-up time is obtained. The value of Ti0 is different in different start-up and speed-up stages.

[0093] Finally, using the correction amount FF3 for the unit warm-up time based on the lower half inner wall temperature TT1 of the cylinder inlet chamber, the correction amount FF4 for the unit warm-up time based on the real-time value change rate of the variable, and the initial value Ti0 of the unit start-up warm-up time, the corrected unit start-up warm-up time Ti is calculated. Specifically, it can be calculated using the formula: Ti=Med[0.7×Ti0,Ti0-FF3-FF4,Ti0].

[0094] This invention also provides a parameter control system adapted to the aforementioned method for correcting automatic start-up parameters of a back-pressure steam turbine during hot start-up. Specifically, it includes: a unit monitoring module for acquiring real-time values ​​of variables affecting the unit's start-up parameters, temperature data of the lower half of the cylinder inlet chamber at the current moment of ATC activation, and initial values ​​of the unit's start-up parameters; a data transmission module for calling up the real-time values ​​of variables affecting the unit's start-up parameters, the temperature data of the lower half of the cylinder inlet chamber at the current moment of ATC activation, and the initial values ​​of the unit's start-up parameters, and transmitting them to a data processing module; and a data processing module. The module is used to calculate the correction amount of the real-time value change rate of the variables affecting the unit's start-up parameters using real-time value data, and generate the first correction amount; the data processing module is used to calculate the correction amount of the lower half of the cylinder inlet chamber temperature on the unit's start-up parameters using the current moment's cylinder inlet chamber temperature data input by the unit's ATC, and generate the second correction amount; the data processing module is used to calculate the corrected unit start-up parameters using the initial value data of the unit's start-up parameters, the first correction amount, and the second correction amount; the control module is used to acquire the corrected unit start-up parameters and control the unit's operation.

[0095] The present invention also provides a parameter control system adapted to the above-mentioned method for correcting automatic start-up parameters of a back-pressure steam turbine under hot conditions, specifically including: a unit monitoring module, used to acquire data on real-time values ​​of variables affecting unit start-up parameters, temperature data of the lower half of the inner wall of the cylinder inlet chamber at the current moment when the unit ATC is engaged, and initial value data of unit start-up parameters;

[0096] The data transmission module is used to call up the real-time values ​​of variables affecting the unit's start-up parameters, the temperature data of the lower half of the cylinder inlet chamber at the current moment when the unit's ATC is activated, and the initial value data of the unit's start-up parameters, and transmit them to the data processing module.

[0097] The data processing module is used to calculate the correction amount of the real-time value change rate of the variable affecting the unit's start-up parameters using the real-time value data of the variable, and generate the first correction amount;

[0098] The data processing module is used to calculate the correction amount of the cylinder inlet chamber lower half inner wall temperature to the unit's start-up parameters using the current moment's cylinder inlet chamber lower half inner wall temperature data input by the unit's ATC, and generate a second correction amount.

[0099] The data processing module is used to calculate the corrected unit start-up parameters using the initial values ​​of the unit start-up parameters, the first correction amount, and the second correction amount;

[0100] The control module is used to acquire the unit's corrected start-up parameters and control the unit's operation.

[0101] like Figure 2As shown, the present invention also provides an automatic start-up control method for a back-pressure steam turbine in hot operation. In the step of gradually increasing the unit speed from the primary target speed Z1 to the no-load speed Z3, the above-mentioned automatic start-up parameter correction method for a back-pressure steam turbine in hot operation corrects the unit start-up rate and the unit warm-up time.

[0102] By setting up the above technical solution, the parameter correction method can be used to control the unit during the start-up process. Based on the operating status and variables affecting the unit's start-up parameters, the unit's acceleration rate and warm-up time can be adjusted, making the unit's operation more consistent with the current operating status. This reduces the probability of the unit triggering a fault alarm signal. Furthermore, by using the ATC control system and the above parameter correction method to control the unit's operation, errors and workload caused by personnel relying on work experience or technical expertise can be reduced. This improves the efficiency of the unit's acceleration process and the accuracy of anomaly detection. In other words, it reduces human intervention, alleviates the operational requirements of the operators, increases the reliability and safety of the unit's start-up, and enhances the unit's automation level.

[0103] like Figure 5 As shown, before the unit speed-up step, the ATC system can be used to check the unit's hot automatic start-up allowable conditions to ensure that the unit meets the operating conditions. Then, the ATC system is used to control the unit to perform the initial operation step. During the initial operation step, it is determined whether the unit is operating normally. If so, the next step (i.e., the unit speed-up step) is continued. If not, the unit is tripped and the control relationship between the unit and the ATC system is disconnected.

[0104] Specifically, the conditions under which the unit can automatically start up in hot condition include, but are not limited to:

[0105] (1) The main instruments on the turbine side are normal (such as sensors for measuring speed, vibration, axial displacement, relative expansion, etc.; thermocouples and display instruments for oil cooler outlet temperature, bearing return oil temperature, steam pressure temperature, and cylinder metal temperature).

[0106] (2) The turbine expansion differential and axial displacement values ​​are normal.

[0107] (3) The steam turbine body drain valve is open, and the main steam and reheat steam pipeline drain control is in automatic control.

[0108] (4) The lubricating oil is of qualified quality and the oil system is operating normally;

[0109] (5) The bearing inlet and outlet oil temperatures are both normal;

[0110] (6) The fuel level in the tank is above the minimum alarm fault level;

[0111] (7) The change in the turbine rotor bending value relative to the original value is less than the set value (0.03 mm);

[0112] (8) The turning gear runs continuously for more than 2 hours or the turbine trips within 20 minutes;

[0113] (9) The waste heat boiler and gas turbine are operating normally and there is no tripping condition;

[0114] (10) The steam turbine thermal protection is functioning normally;

[0115] (11) The turbine is in a shutdown state and the ETS trip condition has been reset;

[0116] (12) The high-pressure main steam pressure meets the start-up conditions (greater than 2MPa);

[0117] (13) The high-pressure main steam temperature meets the start-up conditions (280~300℃);

[0118] (14) The superheat of the high-pressure main steam is greater than 50°C;

[0119] (15) The temperature difference between the upper and lower inner walls of the steam turbine cylinder shall not exceed 50℃;

[0120] (16) If the temperature of the lower half of the cylinder inlet chamber is higher than 300°C or the unit has been shut down for less than 10 hours, the unit can be considered to be in a hot state.

[0121] (17) DEH rotation speed <100r / min;

[0122] (18) The main steam valve and regulating valve are closed;

[0123] (19) The turbine exhaust electric gate valve is fully open;

[0124] (20) The opening degree of the turbine exhaust electric regulating valve is greater than 80%.

[0125] Furthermore, the ATC system is used to control the unit during the initial operation phase, and to determine whether the unit is operating normally during this phase. Specifically, this includes:

[0126] Use the ATC system to input the ATC start command and start the ATC system control;

[0127] The ATC system automatically initiates the turbine unit tripping command to control the unit and establish safe oil pressure (i.e., successful tripping). During this process, it checks whether the turbine unit tripping is complete. If so, the ATC system initiates the operation command and proceeds to the next step. If not, the ATC system automatically disconnects the unit's ATC control. Specifically, if the unit does not receive a tripping signal 40 seconds after the ATC system automatically initiates the turbine unit tripping command, the ATC system considers the tripping to have failed.

[0128] The unit receives the operating command and controls the main steam valve to fully open and delay for 10 seconds. During this process, the ATC system is used to determine whether the main steam valve is fully open. If it is, the main steam valve is fully open and the next step (i.e., the unit speed-up step) is executed after the delay. If not, the unit is judged to have failed to operate, and the ATC system automatically disconnects the unit's ATC system control. The specific judgment condition is: if the ATC system still does not receive the signal of the main steam valve being fully open 1 minute after the operating command is given, the unit is considered to have failed to operate.

[0129] Specifically, such as Figure 2 As shown, the unit's speed-up process includes a first-stage speed-up step, a second-stage speed-up step, a medium-speed warm-up step, and a third-stage speed-up step.

[0130] The first-stage speed-up step specifically includes controlling the generator set to accelerate to the first-stage target speed Z1 at a first-stage speed-up rate V1. Specifically, the first-stage target speed Z1 preset by the ATC system is first invoked, and the first-stage speed-up rate V1 is input using the parameter control system. Then, the generator set is controlled to accelerate to the first-stage target speed Z1 at the first-stage speed-up rate V1. During this process, it is determined whether the generator set has an abnormal alarm signal. If so, the ATC system controls the generator set to trip, and the ATC system automatically disconnects the generator set's ATC system control. In one embodiment, Z1 can be 500 r / min, and V1 is calculated using V1 = Med[0.8]. V10,V10-FF1+FF2,1.2 The calculation is performed on V10, where V10 can be taken as 150 r / min / min. This calculation process is completed by the parameter control system, and the calculated V1 is transmitted to the ATC system to control the unit's operation. In addition, after the unit accelerates to the first-level target speed Z1, a speed maintenance check is performed before proceeding to the next step (i.e., the second-level speed-up step). The speed maintenance check step includes: using the ATC system to control the unit to maintain the first-level target speed Z1 for a check to determine whether the unit has an alarm fault. If so, the ATC system controls the unit to trip, and the ATC system automatically disconnects the unit's ATC system control. After the fault is repaired, the unit restarts. If not, the next step continues.

[0131] The second-stage speed-up step specifically includes controlling the generator set to accelerate from the primary target speed Z1 to the secondary target speed Z2 at a second-stage speed-up rate V2. Specifically, the secondary target speed Z2 is first preset in the ATC system, and the second-stage speed-up rate V2 is input using the parameter control system. Then, the generator set is controlled to accelerate to the secondary target speed Z2 at the second-stage speed-up rate V2. During this process, it is determined whether the generator set has an abnormal alarm signal. If not, the next step is executed; if so, the generator set is controlled to perform the first alarm fault handling step. In one embodiment, Z2 can be 3800 r / min, and V2 is calculated using V2 = Med[0.8]. V20,V20-FF1+FF2,1.2 V20 is used for calculation, where V20 is 200 r / min / min. This calculation process is completed by the parameter control system, and the calculated V2 is transmitted to the ATC system to control the operation of the unit.

[0132] The medium-speed warm-up process includes controlling the unit to run at a constant speed of the secondary target speed Z2 for warm-up; specifically, the medium-speed warm-up time T2 is input using the parameter control system, and during the medium-speed warm-up process, it is determined whether the unit has an abnormal alarm signal. If not, the next step is executed; if so, the unit is controlled to perform a second alarm fault handling step. In one embodiment, the medium-speed warm-up time T2 can be determined using T2=Med[0.7] The calculation is performed on [T20, T20-FF3-FF4, T20], where T20 can be 10-15 minutes. The parameter control system completes this calculation process and transmits the calculated T2 to the ATC system to control the unit's operation.

[0133] The three-stage speed-up process includes: first, setting a critical speed zone between the secondary target speed Z2 and the no-load speed Z3. The critical speed zone includes a minimum speed and a maximum speed. Specifically, the critical speed zone can be set to 4100 r / min to 5000 r / min, meaning the minimum speed is 4100 r / min and the maximum speed is 5000 r / min. Then, using the ATC system, the generator set is controlled to accelerate from the secondary target speed Z2 to the minimum speed of the critical speed zone at a three-stage acceleration rate V3. During this acceleration, the generator set is checked for any abnormal alarm signals. If no alarm is detected, the process continues to the next step; otherwise, the generator set is controlled to decelerate to the secondary target speed. The rotational speed is Z2; then, the unit is controlled to accelerate from the minimum speed in the critical speed zone to the maximum speed in the critical speed zone at a critical speed acceleration rate V31; finally, the unit is controlled to accelerate from the maximum speed in the critical speed zone to the no-load speed Z3 at a three-stage acceleration rate V3, and during the process of controlling the unit to accelerate from the maximum speed in the critical speed zone to the no-load speed Z3 at a three-stage acceleration rate V3, it is determined whether the unit speed is greater than the three-stage intermediate speed Z31. When the current speed of the unit is greater than the three-stage intermediate speed Z31, it is determined whether the unit has an abnormal alarm signal. If so, the unit is controlled to perform the third alarm fault handling step. In one embodiment, the no-load speed Z3 is 10000 r / min, the three-stage intermediate speed Z31 can be 8000 r / min, and the three-stage acceleration rate V3 uses V3=Med[0.8 V30, V30-FF1+FF2, 1.2 The calculation is performed using V30, where V30 can be taken as 250 r / min / min, and the critical zone acceleration rate V31 can be set to 1000~1200 r / min / min. This calculation process is completed by the parameter control system, and the calculated V3 is transmitted to the ATC system to control the operation of the unit.

[0134] Furthermore, the alarm faults in the above design include, but are not limited to:

[0135] (1) The axial displacement reaches the alarm value (>0.3 or <-0.9 mm);

[0136] (2) The expansion difference reaches the alarm value (>2 or <-1mm);

[0137] (3) The bearing vibration reaches the alarm value (>80mm);

[0138] (4) The vibration of the tile reaches the alarm value (>50mm);

[0139] (5) The bearing metal temperature reaches the alarm value (>105℃);

[0140] (6) The temperature of the working thrust bearing reaches the alarm value (>150℃);

[0141] (7) The bearing oil return temperature reaches the alarm value (>150℃);

[0142] (8) The temperature of the reducer bearing reaches the alarm value (>95℃);

[0143] (9) When the turbine speed is greater than the friction test speed, the temperature difference between the upper and lower inner walls of the cylinder exceeds 50°C.

[0144] like Figure 3 As shown, the first alarm fault handling step includes: determining whether the current speed of the unit is greater than the secondary intermediate speed Z21; if not, controlling the unit speed to decrease to the primary acceleration target speed Z1; if so, controlling the unit to decrease from the current speed to the low-speed warm-up speed Z4 at a fixed deceleration rate A, and after completing the low-speed warm-up at the low-speed warm-up speed Z4, then accelerating to the secondary target speed Z2 at the secondary acceleration rate V2. In one embodiment, the secondary intermediate speed Z21 can be taken as 1200 r / min, the low-speed warm-up speed Z4 can be taken as 1200 r / min, at this time, the fixed deceleration rate A can be taken as 150~200 r / min / min, and the low-speed warm-up time T4 can be achieved using T4=Med[0.7]. The calculation is performed on [T40,Ti0-FF3-FF4,T40], where T40 can be calculated over 10 to 15 minutes. The parameter control system completes this calculation process and transmits the calculated T4 to the ATC system to control the unit's operation.

[0145] The second alarm fault handling steps include: controlling the unit to decelerate from the secondary target speed Z2 to the low-speed warm-up speed Z4 at a fixed deceleration rate A, and after completing the low-speed warm-up at the low-speed warm-up speed Z4, then accelerating to the secondary target speed Z2 at the secondary acceleration rate V2.

[0146] like Figure 4 As shown, the third alarm fault handling steps include: controlling the unit to decelerate from the current speed to the high-speed warm-up speed Z5 at a fixed deceleration rate A, and after completing the high-speed warm-up at the high-speed warm-up speed Z5, then accelerating to the no-load speed Z3 at a fixed acceleration rate B. In one real-time example, the fixed acceleration rate B can be set to 200 r / min, and the high-speed warm-up time T5 can be achieved using T5 = Med[0.7]. The calculation is performed on T50, T50-FF3-FF4, T50, where T50 can be 10-15 minutes. The parameter control system completes this calculation process and transmits the calculated T5 to the ATC system to control the unit's operation.

[0147] Furthermore, to prevent uneven heating of the turbine's metal components, which could lead to excessive thermal stress and deformation, a warm-up period is required before reaching rated speed. This process avoids brittle fracture of the metal materials and excessive thermal stress, while also increasing the rotor's center bore temperature to prevent low-temperature brittle fracture. During the warm-up process, the adequacy of the warm-up can be determined by monitoring trends in turbine cylinder expansion and the temperature difference between the upper and lower cylinders, thus confirming whether to continue or terminate the warm-up and proceed with speed increase. To increase the unit's flexibility, an ATC system can be used to send a warm-up interruption signal, allowing the unit to prematurely terminate the warm-up and proceed to the next step.

[0148] The above embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention shall fall within the scope of protection claimed by the present invention.

Claims

1. A method for automatically correcting start-up parameters during hot start-up of a back-pressure steam turbine, characterized in that, include: S1: During the automatic start-up process of the unit, obtain the real-time values ​​of several variables that affect the start-up parameters of the unit, and calculate the rate of change of the real-time values ​​of the variables; S2: Filter the maximum value of the real-time value change rate of the variable, and use it to calculate the correction amount of the real-time value change rate of the variable to the unit start-up parameters, and generate the first correction amount; S3: Obtain the temperature of the lower half of the inner wall of the cylinder inlet chamber at the current moment when the unit's ATC is engaged, and use it to calculate the correction amount of the lower half of the inner wall of the cylinder inlet chamber to the unit's start-up parameters, and generate the second correction amount. S4: Obtain the initial values ​​of the unit's start-up parameters; S5: Calculate the corrected unit start-up parameters using the first correction amount, the second correction amount, and the initial values ​​of the unit start-up parameters; The unit start-up parameters include the unit start-up rate and the unit warm-up time; The second correction includes the correction FF2 for the turbine's acceleration rate caused by the lower half inner wall temperature TT1 of the cylinder inlet chamber, which is calculated using the following formula: FF2 = Max[FF20, 0]; FF20=K1×(TT1-TT_0-△T) / TT_0; The second correction also includes a correction factor FF3 for the warm-up time of the unit based on the lower half inner wall temperature TT1 of the cylinder inlet chamber, which is calculated using the following formula: FF3 = Max[FF30, 0]; FF30=K2×(TT1-TT_0-△T) / TT_0; Where TT_0 is the set value of the lower half of the inner wall temperature of the cylinder inlet chamber when judging the hot state of the unit; △T is the temperature offset margin; K1 is the correction coefficient of the unit's start-up rate; K2 is the correction coefficient of the unit's start-up warm-up time.

2. The method for correcting automatic start-up parameters of a back-pressure steam turbine during hot start-up according to claim 1, characterized in that, The first correction amount includes the correction amount FF1 for the rate of change of the real-time value of the variable on the unit's start-up rate, which is calculated using the following formula: FF1 = K3 × Rate_v; Among them, Rate_v is the maximum value of the real-time change rate of the variable affecting the unit's start-up rate; The first correction also includes a correction factor FF4 for the rate of change of the real-time value of the variable on the unit's warm-up time, which is calculated using the following formula: FF4 = Ti1 - K4 × Rate_t; Where Ti1 is the maximum correction bias of the variable affecting the unit warm-up time on the unit warm-up time; K4 is the correction coefficient of the variable affecting the unit warm-up time on the unit warm-up time; and Rate_t is the maximum value of the real-time change rate of the variable affecting the unit warm-up time.

3. The method for correcting automatic start-up parameters of a back-pressure steam turbine under hot conditions according to claim 2, characterized in that, The unit's corrected start-up parameters include the unit's corrected start-up rate of increase Vi, which is calculated using the following formula: Vi=Med[0.8×Vi0,Vi0-FF1+FF2,1.2×Vi0]; Where Vi0 is the initial value of the unit's initial acceleration rate; The unit correction start-up parameters also include the unit correction warm-up time Ti, which is calculated using the following formula: Ti=Med[0.7×Ti0,Ti0-FF3-FF4,Ti0]; Where Ti0 is the initial value of the unit's start-up and warm-up time.

4. A parameter control system adapted to the automatic start-up parameter correction method for a back-pressure steam turbine under hot conditions as described in any one of claims 1 to 3, characterized in that, include: The unit monitoring module is used to acquire real-time data of variables affecting the unit's start-up parameters, temperature data of the lower half of the cylinder inlet chamber at the moment the unit's ATC is activated, and initial value data of the unit's start-up parameters. The data transmission module is used to call the real-time values ​​of the variables affecting the unit's start-up parameters, the temperature data of the lower half of the cylinder inlet chamber at the current moment when the unit's ATC is activated, and the initial value data of the unit's start-up parameters, and transmit them to the data processing module. The data processing module is used to calculate the correction amount of the real-time value change rate of the variable affecting the unit's start-up parameters using the real-time value data of the variable, and generate a first correction amount; The data processing module is used to use the temperature data of the lower half of the cylinder inlet chamber of the unit's ATC input at the current moment, calculate the correction amount of the temperature of the lower half of the cylinder inlet chamber to the unit's start-up parameters, and generate a second correction amount. The data processing module is used to calculate the corrected unit start-up parameters using the initial value data of the unit start-up parameters, the first correction amount, and the second correction amount; The control module is used to acquire the unit's corrected start-up parameters and control the unit's operation.

5. A method for automatic start-up control of a back-pressure steam turbine under hot conditions, characterized in that, include: In the unit speed-up step, in which the unit speed is gradually increased from the target speed Z1 to the no-load speed Z3, the unit speed-up rate and the unit warm-up time are corrected by the automatic start-up parameter correction method for hot start of back-pressure steam turbine as described in any one of claims 1 to 3.

6. The method for automatic start-up control of a back-pressure steam turbine under hot conditions according to claim 5, characterized in that: The unit speed-up steps include: The first-stage speed-up process includes controlling the unit to speed up to the first-stage target speed Z1 at a first-stage speed-up rate V1; The second-stage acceleration step includes controlling the unit to accelerate from the first-stage target speed Z1 to the second-stage target speed Z2 at a second-stage acceleration rate V2. The medium-speed warm-up process includes controlling the unit to run at a constant speed of the secondary target speed Z2 for warm-up. The three-stage acceleration process includes: setting a critical speed zone between the secondary target speed Z2 and the no-load speed Z3, wherein the critical speed zone includes a minimum speed and a maximum speed; controlling the unit to accelerate from the secondary target speed Z2 to the minimum speed of the critical speed zone at a three-stage acceleration rate V3; controlling the unit to accelerate from the minimum speed of the critical speed zone to the maximum speed of the critical speed zone at a critical speed zone acceleration rate V31; and controlling the unit to accelerate from the maximum speed of the critical speed zone to the no-load speed Z3 at a three-stage acceleration rate V3. The warm-up time of the first-stage acceleration rate V1, the second-stage acceleration rate V2, the third-stage acceleration rate V3, and the medium-speed warm-up step is corrected by the automatic stroke parameter correction method.

7. The method for automatic start-up control of a back-pressure steam turbine under hot conditions according to claim 6, characterized in that: During the second-stage speed-up process, it is determined whether the unit has an abnormal alarm signal. If so, the unit is controlled to perform the first alarm fault handling step. During the medium-speed warm-up process, it is determined whether the unit has an abnormal alarm signal. If so, the unit is controlled to perform the second alarm fault handling step. During the process of the control unit accelerating from the secondary target speed Z2 to the minimum speed in the critical speed range at a three-level acceleration rate V3, it is determined whether the unit has an abnormal alarm signal. If so, the control unit decelerates to the secondary target speed Z2. During the process of the control unit accelerating from the maximum speed in the critical speed range to the no-load speed Z3 at the three-stage acceleration rate V3, if the current speed of the unit is greater than the three-stage intermediate speed Z31, it is determined whether the unit has an abnormal alarm signal. If so, the control unit performs the third alarm fault handling step.

8. The method for automatic start-up control of a back-pressure steam turbine under hot conditions according to claim 7, characterized in that: The first alarm fault handling step includes: determining whether the current speed of the unit is greater than the secondary intermediate speed Z21; if not, controlling the unit speed to decrease to the primary acceleration target speed Z1; if so, controlling the unit to decrease from the current speed to the low-speed warm-up speed Z4 at a fixed deceleration rate A, and after completing the low-speed warm-up at the low-speed warm-up speed Z4, accelerating to the secondary target speed Z2 at the secondary acceleration rate V2. The second alarm fault handling steps include: controlling the unit to decelerate from the secondary target speed Z2 to the low-speed warm-up speed Z4 at the fixed deceleration rate A, and after completing the low-speed warm-up at the low-speed warm-up speed Z4, then accelerating to the secondary target speed Z2 at the secondary acceleration rate V2. The warm-up time for low-speed warm-up is corrected by the automatic rev-up parameter correction method.

9. The method for automatic start-up control of a back-pressure steam turbine under hot conditions according to claim 7, characterized in that: The third alarm fault handling steps include: The control unit decelerates from the current speed to the high-speed warm-up speed Z5 at a fixed deceleration rate A, and after completing the high-speed warm-up at the high-speed warm-up speed Z5, it accelerates to the no-load speed Z3 at a fixed acceleration rate B.

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