A three-unit generator splitting process control system, method, device and medium

Abstract

The present application belongs to the technical field of petrochemical power generation, and particularly relates to a three-unit generator tripping process control system, method, equipment and medium; the system detects a tripping signal through a digital input DI unit and transmits the signal to a PLC controller, the PLC controller starts a tripping process control program, calculates a real-time rotating speed value of a steam turbine transmitted by an analog input AI unit and dynamically outputs a proportional adjustment parameter to a PID controller, the PID controller internally operates and outputs a valve position signal to a servo system of a main regulating valve of the steam turbine through an analog output AO unit, and finally reduces the rotating speed of the steam turbine; a three-unit generator tripping process control method realizes tripping process control by using the system; the equipment and medium are used for storing a computer program, and realize the tripping process control system when the program is executed; the present application can effectively avoid the whole unit tripping caused by generator tripping, and stably control the rotating speed of the steam turbine at a target rotating speed.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of petrochemical power generation, and particularly relates to a three-unit generator splitting process control system, method, equipment and medium. BACKGROUND

[0002] Petrochemical power generation recovers the surplus heat generated in the industrial production process and converts it into electric energy, which not only improves energy utilization efficiency, but also reduces environmental pollution and realizes sustainable development. In this field, a large amount of heat generated in the process of boiler recovery is recovered, steam is generated and sent to a steam turbine to drive the steam turbine to rotate and drive an axial flow fan to rotate to provide the required air volume for process production, forming an effective and stable energy recovery device. The surplus energy drives a generator set and is connected to the grid to generate electricity, which greatly reduces the user's project construction investment, helps the user to realize the overall process configuration optimization and energy efficiency optimization of different chemical devices, and creates high-quality development and carbon emission reduction in the entire production process of the industrial park. The three-unit device (hereinafter referred to as three-unit) includes a steam turbine, an axial flow fan and a generator. The steam turbine mainly drives the axial flow fan to rotate to continuously and stably supply air to the reactor. The generator plays an auxiliary role and uses the surplus energy of the steam turbine to generate electricity.

[0003] Splitting refers to the technical measure of cutting off the connection between the generator and other parts of the power system when they lose synchronization and cannot recover synchronization, and dividing them into two independent and unrelated parts. It is an important measure to ultimately maintain the stable operation of the power system and prevent accidents from expanding to cause serious consequences. When the generator in the three-unit needs to be withdrawn from the grid due to various factors, especially due to the generator withdrawal from the grid caused by fault interlocking, the power output by the steam turbine to the generator is very large. The sudden splitting of the generator is easy to cause the three-unit to be suddenly unloaded due to the power of the steam turbine acting on the generator, which causes the steam turbine to overspeed. At this time, the three-unit is easy to execute the stop interlocking value due to overspeed safety setting and directly cause the unit to trip, thereby affecting the production of the entire process and causing economic losses. At the same time, the low safety and low efficiency cannot meet the requirements of the factory for safe production.

[0004] In the prior art, the patent with the patent publication number CN112431642A and the name of a steam turbine system based on FCB control logic discloses that the generator outlet switch is in the closed position, the main transformer high-voltage side outlet switch is in the open position, an FCB (Fast Cut Back) signal is formed, the DEH (Digital Electro-hydraulic Regulating System) controls the steam turbine speed at 3000 rpm, and the FCB signal is sent to the DCS (Distributed Control System) at the same time. After the FCB action, in order to open the regulating door in time, a OPC (OLE for Process Control) function is added to control the steam turbine speed below 3020 rpm after the OPC trigger, which has the effect of preventing the steam turbine from overspeeding due to the FCB signal; but the invention cannot realize the above-mentioned function on the steam turbine without the OPC solenoid valve, and cannot solve the problem of directly causing the unit trip due to the execution of the shutdown interlock value caused by the overspeed safety setting of the three-unit generator. SUMMARY

[0005] In order to overcome the shortcomings of the prior art, the purpose of the present application is to provide a three-unit generator splitting process control system, method, device and medium, which acquires the generator splitting signal and real-time speed data, calculates the target speed of the steam turbine and outputs a proportional regulating parameter to the PID controller, which is used to control the opening and closing of the steam turbine main regulating door, so as to realize that the three-unit generator will not cause the unit trip due to overspeed after the generator is disconnected from the grid, and the speed of the three-unit generator is stabilized at the target speed.

[0006] To achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0007] In the first aspect, a three-unit generator splitting process control system comprises a signal detection module, a regulating instruction generation module and a control execution module.

[0008] The signal detection module comprises a digital input DI unit and an analog input AI unit, the digital input DI unit is used to detect the generator splitting signal and transmit it to the regulating instruction generation module, and the analog input AI unit is used to detect the real-time speed value of the steam turbine and transmit it to the regulating instruction generation module.

[0009] The regulating instruction generation module comprises a PLC controller, when the PLC controller receives the splitting signal, the PLC controller sends the splitting instruction to the control execution module, and at the same time, the PLC controller starts the splitting process control program, the splitting process control program inputs the real-time speed value of the steam turbine received by the PLC controller and the speed set value of the steam turbine into a linear function, calculates and generates a proportional regulating parameter through the linear function, and the PLC controller dynamically sends the proportional regulating parameter to the control execution module.

[0010] The control execution module comprises a PID controller, which, after receiving the tripping instruction, converts the control state of the PID controller itself into an automatic mode, and the PID controller further comprises an analog output (AO) unit, the PID controller, after receiving the proportional adjustment parameter, performs internal proportional integral operation and generates a final result, and the PID controller converts the final result into a valve position signal through the analog output (AO) unit and outputs the valve position signal to the servo system of the turbine main regulating valve.

[0011] Further, the linear function formula is as follows:

[0012] y=k(x1-x0)+b (1)

[0013] In formula (1), y is the proportional adjustment parameter, x0 is the turbine speed set value, x1 is the real-time turbine speed value, x1-x0 is the speed difference, k is the slope determined by test, and b is the intercept determined by test.

[0014] Further, the adjustment instruction generation module further comprises a pulse timer, the PLC controller activates the pulse timer when starting the tripping process control program, the pulse timer counts down the execution time of the tripping process control program, and when the execution time is completed, the tripping process control program is automatically terminated and exited.

[0015] The second aspect is a tripping process control method of a three-unit generator, based on the tripping process control system, comprising the following steps:

[0016] S1: During the normal operation of the three-unit generator, when the digital input (DI) unit of the signal detection module detects a tripping signal, the digital input (DI) unit transmits the tripping signal to the PLC controller in the adjustment instruction generation module, and at the same time, the analog input (AI) unit of the signal detection module transmits the detected real-time turbine speed value to the PLC controller in the adjustment instruction generation module;

[0017] S2: When the PLC controller receives the tripping signal in step S1, the PLC controller sends a tripping instruction to the control execution module, and at the same time, the PLC controller starts a tripping process control program, the tripping process control program inputs the real-time turbine speed value received by the PLC controller in step S1 and the turbine speed set value into a linear function, calculates and dynamically generates a proportional adjustment parameter through the linear function, and the PLC controller dynamically sends the proportional adjustment parameter to the control execution module;

[0018] S3: When the PID controller receives the step S2 said column instruction, the control state of the PID controller itself is converted to automatic mode, the PID controller receives step S2 said proportional adjustment parameter, carries out internal proportional integral operation and generates the final result, the PID controller converts the final result into valve position signal through analog output AO unit and outputs to the servo system of the turbine main regulating valve;

[0019] S4: Repeat steps S1 to S3 until the real-time speed value of the turbine is stable at the turbine speed set value.

[0020] Further, the linear function formula in step S2 is as follows:

[0021] y=k(x1-x0)+b (2)

[0022] In formula (2), y is the proportional adjustment parameter, x0 is the turbine speed set value, x1 is the real-time speed value of the turbine, x1-x0 is the speed difference, k is the slope determined by test, and b is the intercept determined by test.

[0023] Further, the adjustment instruction generation module in step S2 further comprises a pulse timer, the PLC controller activates the pulse timer when starting the column process control program, the pulse timer counts down the execution time of the column process control program, when the execution time is completed, the column process control program is automatically terminated and exited, and the column process control method is terminated.

[0024] Third aspect, an electronic device comprising a memory and a processor:

[0025] Memory: for storing a computer program for implementing the column process control system;

[0026] Processor: for executing the computer program to implement the column process control system.

[0027] Fourth aspect, a computer readable storage medium, the computer readable storage medium stores a computer program, the computer program is executed by the processor to implement the column process control system.

[0028] Compared with the prior art, the beneficial effects of the present application are:

[0029] 1. The system detects the generator column signal through the digital input DI unit and sends the signal to the PLC controller, the PLC controller can start the column process control program instantly after receiving the column signal, which can effectively avoid the three-unit trip caused by overspeed after the generator column.

[0030] 2. The system calculates the current working condition information by a linear function, outputs proportional adjustment parameters to the PID controller in real time, and controls the turbine speed to be stable at the target speed within the pulse time obtained by the test, and has the characteristics of simple operation and reliable operation.

[0031] In summary, the system can effectively avoid the entire unit trip caused by generator splitting, ensure the safe and stable operation of production operation, greatly reduce the probability of interlock reaction caused by unit trip of axial flow fan participating in the process, avoid unnecessary loss, and significantly improve the production reliability and intelligent level. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 The figure is a schematic diagram of the splitting process control system of the application. DETAILED DESCRIPTION

[0033] The application will be further described below. Figure 1 The application will be further described below.

[0034] In a first aspect, a three-unit generator splitting process control system includes a signal detection module, an adjustment instruction generation module, and a control execution module.

[0035] The signal detection module includes a digital input (DI) unit and an analog input (AI) unit, the digital input (DI) unit is used to detect the generator splitting signal and transmit the splitting signal to the adjustment instruction generation module, the splitting signal specifically refers to the signal that two or more of the three parallel grid breakers of the generator are switched from closing to opening, and the analog input (AI) unit is used to detect the real-time speed value of the turbine and transmit the real-time speed value of the turbine to the adjustment instruction generation module, the digital input (DI) unit and the analog input (AI) unit used in the system are conventional devices, for example, the digital input (DI) unit is Siemens 6ES7321-7BH01-0AB0 and Siemens 6ES7521-1BL00-0AB0, and the analog input (AI) unit is Siemens 6ES7331-7NF00-0AB0 and Siemens 6ES7531-7KF00-0AB0.

[0036] The adjustment instruction generation module comprises a PLC controller, when the PLC controller receives the splitting signal, the PLC controller sends a splitting instruction to the control execution module, and meanwhile the PLC controller starts a generator splitting process control program, the splitting process control program inputs the real-time rotating speed value of the steam turbine received by the PLC controller and the rotating speed setting value of the steam turbine into a linear function, and through the rotating speed difference between the rotating speed setting value and the real-time rotating speed value, the linear function calculates and dynamically generates a proportional adjustment parameter, and the PLC controller dynamically sends the proportional adjustment parameter to the control execution module;

[0037] The control execution module comprises a PID controller, after receiving the splitting instruction, the PID controller forcibly converts the control state of the PID controller itself into an automatic mode, the automatic mode is directly controlled by the PLC controller compared with the manual mode, and the PID controller further comprises an analog output AO unit, after receiving the proportional adjustment parameter, the PID controller performs internal proportional integral operation and generates a final result, the PID controller converts the final result into a valve position signal through the analog output AO unit and outputs the valve position signal to a servo system of a steam turbine main regulating valve, and the steam turbine main regulating valve servo system completes valve position control through a servo valve according to the received valve position signal, so that the rotating speed of the steam turbine is reduced, and the analog output AO unit is, for example, a Siemens 6ES7332-5HF00-OAB0 or a Siemens 6ES7532-5HF00-0AB0.

[0038] Further, the adjustment instruction generation module further comprises a pulse timer, when the PLC controller starts the splitting process control program, the PLC controller activates the pulse timer, the pulse timer counts down the execution time of the generator splitting process control program, when the execution time is completed, the splitting process control program is automatically terminated and exited, at this time, the rotating speed control state of the steam turbine is in the automatic mode, and the steam turbine runs according to the rotating speed setting value in the splitting process control program, so that the rotating speed of the steam turbine is maintained at the setting value for a long time, the execution time of the pulse timer is the time required for the rotating speed of the steam turbine to stabilize to the rotating speed setting value, and when the manually set execution time is controlled to be greater than 10 s, the rotating speed of the steam turbine is reduced from the rotating speed in the splitting stage to the rotating speed setting value and maintained at the rotating speed setting value.

[0039] In a second aspect, as shown in Figure 1 A three-unit generator splitting process control method based on the three-unit generator splitting process control system, comprising the following steps:

[0040] S1: In the process of normal operation of the three-unit set, when the digital input DI unit of the signal detection module detects a generator splitting signal, the digital input DI unit transmits the splitting signal to the regulation instruction generation module, and the analog input AI unit of the signal detection module transmits the detected real-time rotating speed value of the steam turbine to the regulation instruction generation module;

[0041] S2: When the PLC controller receives the splitting signal in step S1, the PLC controller sends a splitting instruction to the control execution module, and starts a splitting process control program of the generator. The splitting process control program inputs the real-time rotating speed value of the steam turbine received by the PLC controller in step S1 and the rotating speed set value of the steam turbine into a linear function, calculates and dynamically generates a proportional regulation parameter through the linear function, and the PLC controller dynamically sends the proportional regulation parameter to the control execution module.

[0042] S3: When the PID controller receives the splitting instruction in step S2, the control state of the PID controller is forcibly converted to an automatic mode. After the PID controller receives the proportional regulation parameter in step S2, the PID controller performs internal proportional integral operation and generates a final result. The PID controller converts the final result into a valve position signal through an analog output AO unit and outputs the valve position signal to a servo system of a main regulating valve of the steam turbine. The main regulating valve servo system of the steam turbine controls the valve position through a servo valve according to the received valve position signal, gradually adjusts the rotating speed of the steam turbine to the set value, and finally adjusts the rotating speed of the steam turbine to the set value within the execution time of the pulse timer.

[0043] S4: Repeat steps S1 to S3 until the real-time rotating speed value of the steam turbine is stabilized at the rotating speed set value of the steam turbine.

[0044] Further, the regulation instruction generation module in step S2 further comprises a pulse timer. When the PLC controller starts the splitting process control program, the PLC controller activates the pulse timer. The pulse timer counts down the execution time of the generator splitting process control program. When the execution time is completed, the splitting process control program is automatically terminated and exited, and the splitting process control method is terminated. At this time, the rotating speed control state of the steam turbine is in an automatic mode. At this time, the steam turbine will run according to the rotating speed set value in the splitting process control program. The execution time of the pulse timer, i.e. the time required for the steam turbine to stabilize the rotating speed to the rotating speed set value, is measured by test. When the manually set execution time is controlled to be more than 10s, the rotating speed of the steam turbine will be maintained at the rotating speed set value.

[0045] Embodiment

[0046] The following describes the technical solution of the present application in further detail by taking a generator splitting process control system of a three-unit set (including a steam turbine, an axial flow fan and a generator) as an embodiment.

[0047] In the process of normal operation of the three-machine set, the generator power is 10.67MW, the opening of the main regulating valve of the steam turbine is 28.6%, when the generator is manually disconnected from the power grid, the generator power immediately reduces to 0MW, the opening of the main regulating valve of the steam turbine is reduced to 18% at the minimum, and the rotating speed is 3100rpm at the maximum, after the execution of the generator disconnection process control method for 10s, the rotating speed of the steam turbine is stabilized at the set value of 3000rpm and runs; the test proves that the generator disconnection process control system and method in the application can effectively control the rotating speed of the steam turbine below 3100rpm after the generator is disconnected, and in the 10s pulse time of the generator disconnection process control program, the system can maintain the rotating speed of the three-machine set at 3000rpm, realizes the normal operation of the three-machine set, and makes the axial flow fan to stably send air, as shown in Table 1, the disconnection process control program calculates the proportional adjustment parameter (the rotating speed set value of the steam turbine is 3000rpm) output to the PID controller according to the rotating speed difference between the rotating speed set value and the real-time rotating speed value, and the k value and b value in the linear function can be obtained through two sets of test parameters, and the k value and b value are continuously corrected by using other test parameters.

[0048] Table 1: Proportional adjustment parameter table generated by the disconnection process control program

[0049] Serial number 1 2 3 4 Differential rotation speed (rpm) 50 100 120 150 Proportional regulation parameter 0.05 0.08 0.15 0.2

[0050] In a third aspect, an electronic device includes a memory and a processor, wherein:

[0051] The memory is used to store a computer program for realizing the three-machine set generator disconnection process control system.

[0052] The processor is used to realize the three-machine set generator disconnection process control system when the computer program is executed.

[0053] In a fourth aspect, a computer readable storage medium stores a computer program, and the computer program is executed by a processor to realize the three-machine set generator disconnection process control system; the computer readable storage medium includes: a U disk, a read-only memory (ROM), a random access memory (RAM), a mobile hard disk, a magnetic disk or an optical disk and various storage program codes.

[0054] The working principle of the application is:

[0055] When the digital input DI unit in the signal detection module detects the generator split signal, it is transmitted to the PLC controller in the regulation instruction generation module. After receiving the split signal, the PLC controller sends a split instruction to the control execution module to convert the PID controller control state to automatic mode. When the PLC controller receives the split signal, it starts the split process control program. By receiving the real-time turbine speed value transmitted by the analog input AI unit, the proportional adjustment parameter is calculated and dynamically output to the PID controller. The PID controller internally calculates and outputs the valve position signal to the servo system of the turbine main control valve through the analog output AO unit. The servo system controls the valve position through the servo valve, reduces the turbine speed, and ultimately reduces the turbine speed to the target value within a certain time by dynamically receiving the real-time turbine speed value and dynamically outputting the valve position signal.

Claims

1. A three-unit generator split process control system, characterized by, The signal detection module, the regulation instruction generation module, and the control execution module are included. The signal detection module includes a digital input (DI) unit and an analog input (AI) unit. The regulation instruction generation module includes a PLC controller. The control execution module includes a PID controller.

2. The split-phase control system of claim 1, wherein, The linear function formula is as follows: y=k(x1-x0)+b (1) In formula (1), y is the proportional regulation parameter, x0 is the turbine speed set value, x1 is the real-time turbine speed value, x1-x0 is the speed difference, k is the slope determined by testing, and b is the intercept determined by testing.

3. The split-phase control system of claim 1, wherein, The regulation instruction generation module further includes a pulse timer.

4. A method of a three-generator unit split process control based on the split process control system of claim 1, characterized in that, The following steps are included: S1: During normal operation of the three-machine unit, when the digital input (DI) unit of the signal detection module detects a trip signal, the DI unit transmits the trip signal to the PLC controller in the regulation instruction generation module. S2: When the PLC controller receives the trip signal in step S1, the PLC controller sends a trip instruction to the control execution module and starts a trip process control program. S3: The trip process control program inputs the real-time turbine speed value received by the PLC controller and the turbine speed set value into a linear function. S4: The trip process control program calculates and dynamically generates a proportional regulation parameter through the linear function. S5: The PLC controller dynamically sends the proportional regulation parameter to the control execution module. S6: The PID controller receives the trip instruction and converts its control state to automatic mode. S7: The PID controller receives the proportional regulation parameter and performs internal proportional integral operation to generate a final result. S8: The PID controller converts the final result into a valve position signal through the analog output (AO) unit and outputs the valve position signal to the servo system of the turbine main control valve. S3: When the PID controller receives the step S2 said column resolution instruction, the control state of the PID controller itself into the automatic mode, the PID controller receives step S2 said proportional adjustment parameter after the internal proportional integral operation and generate the final results, PID controller through the analog output AO unit will be the final results into the valve position signal and output to the turbine main valve servo system; S4: Repeat steps S1 to S3, until the real-time speed value of the steam turbine is stable at the steam turbine speed set value.

5. The method of claim 4, wherein, The linear function formula in step S2 is as follows: y=k(x1-x0)+b (2) In formula (2), y is the proportional adjustment parameter, x0 is the steam turbine speed set value, x1 is the real-time speed value of the steam turbine, x1-x0 is the speed difference, k is the slope determined by the test, and b is the intercept determined by the test.

6. The method of claim 4, wherein, The adjustment instruction generation module in step S2 further comprises a pulse timer. When the PLC controller starts the column resolution process control program, the PLC controller activates the pulse timer. The pulse timer counts down the execution time of the column resolution process control program. When the execution time is completed, the column resolution process control program is automatically terminated and exited, and the column resolution process control method is terminated.

7. An electronic device comprising a memory and a processor, characterized in that: the memory is used to store a computer program for implementing the column resolution process control system according to any one of claims 1 to 3; the processor is used to execute the computer program to implement the column resolution process control system according to any one of claims 1 to 3.

8. A computer-readable storage medium, characterized in that, The computer readable storage medium stores a computer program, and the computer program is executed by the processor to implement the column resolution process control system according to any one of claims 1 to 3.

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