Fault self-diagnosis method for steam turbine main engine combined valve activity test control loop

Abstract

The invention discloses a steam turbine main engine combined valve activity test control loop fault self-diagnosis method. The method comprises the following steps: establishing a fault self-diagnosis picture; displaying an interruption step and an interruption condition; establishing a step feedback condition unsatisfied condition memory logic, wherein the step feedback condition unsatisfied condition memory logic comprises a step control logic FS-OP principle trigger condition; a logic fault memory function; testing step fault recording; after the fault processing is completed, an alarm reset button is pressed to clear the alarm, and then the next test can be carried out. According to the diagnosis method, the control loop fault self-diagnosis picture is established, the step serial number of interruption of the steam turbine main engine valve activity test is displayed, and the cause of the fault in the step is displayed, so that the dependence of operators on professional technicians is reduced, the technical requirements of the professional technicians are reduced, and the working efficiency is improved. And an operator can be helped to timely and accurately judge problems and take measures for preventing fault expansion. The fault processing efficiency is improved, and the unit safety is improved.

Description

Technical Field

[0001] The invention relates to the field of steam turbines, and in particular to a self-diagnosis method for a control loop fault of a steam turbine main engine combined with a valve activity test. Background Art

[0002] The ultra-supercritical steam turbine is designed with nine hydraulic motors: two for the high-pressure main steam valve, two for the high-pressure throttle, two for the reheat main steam valve, and two for the reheat throttle. Each motor consists of a main motor module, which drives the main steam valve or throttle actuator according to control requirements. The motor control equipment includes a shutoff solenoid valve, a directional valve (for the main steam valve), an electro-hydraulic servo valve (for the throttle), and hydraulic piping.

[0003] Function of the quick-closing solenoid valve: used for locking and tripping the steam turbine and providing EH oil pressure for the operation of the oil motor.

[0004] Function of the directional valve: Controls the opening and closing of the main steam valve when the unit is shut down.

[0005] Function of electro-hydraulic servo valve: accept the output command of the controller to adjust the switch of the throttle.

[0006] Function of displacement sensor: measure the opening position of main steam valve and regulating valve.

[0007] The corresponding main steam valve and regulating valve form a control component and are supplied with oil by the same oil supply circuit.

[0008] The aforementioned equipment status and control signals are controlled by the computer logic of the turbine control system DEH. The turbine control system DEH is implemented using Siemens T3000-SPPA control software. The steam turbine main engine valve ATT (Associated Valve) valve movement test system consists of four valve assemblies: high-pressure valve A and high-pressure regulating valve A, high-pressure valve B and high-pressure regulating valve B, intermediate-pressure valve A and intermediate-pressure regulating valve A, and intermediate-pressure valve B and intermediate-pressure regulating valve B. These valve assemblies share a common test step control logic. The movement test logic for each valve assembly is an "OR" operation.

[0009] According to the "Twenty-five Requirements for Preventing Major Accidents in Power Production", the main steam valve, regulating valve, reheat main steam valve and regulating valve on the operating unit must be ensured not to be stuck. Therefore, the valves must be subjected to regular activity tests (ATT) on the operating units to check whether the control circuit and solenoid valve are working normally and the activity of the actuator.

[0010] The normal test steps are as follows: 1: Run the test and put the SLC of the combined valve into operation, and click the ATT test button 2: Step 1, Step 2: Empty steps; 3: Step 3: Lower the valve limit of the regulating valve. The regulating valve is affected by the valve limit and closes at a certain slope; 4: Step 4: Empty step; 5: Step 5: When the regulating valve is closed, the main steam valve fast closing solenoid valve 1 and the directional valve are actuated, and the main steam valve is closed; 6: Step 6: After the main steam valve is closed, the main steam valve fast closing solenoid valve 1 and the directional valve are reset, and the main steam valve is opened; 7: Step 7: After the main steam valve is fully opened, the main steam valve quick closing solenoid valve 2 and the directional valve are actuated, and the main steam valve is closed; 8: After the main steam valve is closed, the regulating valve limit is raised and the regulating valve is opened; 9: Step 9: After the regulating valve is fully opened, the regulating valve fast closing solenoid valve 1 is actuated and the regulating valve limit is lowered at the same time, and the regulating valve is closed; 10: After the regulating valve is closed, the regulating valve fast closing solenoid valve 1 is reset, the regulating valve limit is increased, and the regulating valve is opened; 11: After the regulating valve is fully opened, the regulating valve fast closing solenoid valve 2 is actuated and the regulating valve limit is lowered at the same time, and the regulating valve is closed; 12: Step 12: The test is completed; 13: Step 51: After the regulating valve is closed, the main steam valve fast closing solenoid valve 2 and the directional valve are reset, and the main steam valve is fully opened; 14: Step 52: After the main steam valve is fully opened, the regulating valve quick closing solenoid valve 2 is reset, and the regulating valve is opened to the system instruction.

[0011] 15: Step 53, Step 54, Step 55: Empty steps; 16: Step 56: All throttle valve limits = 105% The control logic divides the test into twelve test steps FS_OP and three test reset steps FS_SD.

[0012] In the test step, the system starts timing after issuing an instruction. When the timing is completed and all signal feedback conditions are met, the system issues an instruction to proceed to the next step. If any signal feedback condition is not met, the monitoring time in the STEP function block is up, the test step ends, and the system directly goes to the test reset step. In the test reset step, when the test reset instruction is issued, timing starts. When the timing is completed, all signal conditions of this step are met, and the next step instruction is issued. If a feedback signal in this step is not met, the system reset step is interrupted.

[0013] Problems: It's unclear at which stage the test is interrupted, or which condition is not met during the interruption. When a system problem occurs, professional technicians are required to review historical data and analyze it in conjunction with the control logic. Summary of the Invention

[0014] The purpose of the present invention is: to overcome the problems existing in the above-mentioned prior art, the present invention proposes a self-diagnosis method for a steam turbine main engine combined with a valve activity test control circuit fault, which helps operating personnel to promptly and accurately judge the problem and take measures to prevent the expansion of the fault.

[0015] The technical solution of the present invention is: The self-diagnosis method for the control loop fault of the steam turbine main engine combined valve movement test includes: Establish fault self-diagnosis screen: display interruption steps and interruption conditions; Establish the memory logic for unsatisfied walking feedback conditions, including: Step control logic FS-OP principle triggering condition: When the previous step instruction is completed, the current step control instruction is activated. When the trigger condition is "1", the CMD instruction output is "1", and the relevant equipment is driven according to the control logic. T_WAIT is the shortest execution cycle of the waiting time of this step. Within the shortest cycle, WT output is "1", T_MON is the monitoring time of this step, and when the monitoring time is up, the CMD instruction is reset to "0". CRIT is the passing condition of this step. When WT is "1" and the feedback condition is "1", this step is completed and triggers NEXT to "1", and continues to trigger the next step instruction. When all test logics are completed, the test recovery logic FS-SD program is executed; if the feedback condition is not met, the walking logic is interrupted and the test program is directly cut off; Logical fault memory function: When the step control instruction is activated, the feedback condition is satisfied, that is, the condition is "1" and recorded; Test step fault record: that is, when the current step instruction CMD sends "1", the signal needs to be reset to the previous step when the next step instruction CMD sends "1"; if the feedback condition of the current step is not met, the next step instruction CMD is not triggered and the step is interrupted; If any condition is not met, the feedback condition on the screen will be displayed in green. Since the test is interrupted, there is no reset for the next step instruction. Other conditions that are met will be displayed in red. After all feedback conditions are met, the next trigger condition is triggered, and the next CMD instruction clears the feedback condition of the previous step to "0" and the screen feedback condition displays green; That is, when the screen step is displayed in red, it means the step where the test is interrupted. In the content column of the step, red means the condition is met, and green means it is not met. When the fault is handled, press the "alarm reset button" to clear the alarm before the next test can be carried out.

[0016] Preferably, the self-diagnosis comprises the test steps of: Logic modification: FS-OP command signal activates the walking program, and no logic modification or screen display is performed on empty steps; S1, S2: empty steps; S3: Reduce the valve limit of high-pressure valve 1 to 0% with a certain slope; Feedback conditions are met: (1) High-pressure valve 1 position feedback is closed; (2) High-pressure valve 1 valve limit = 0%; (3) Combined valve 1 test is put into operation; S4: empty step; S5: Actuate high-pressure main steam valve 1 to shut off solenoid valve 1; Feedback conditions are met: (1) High-pressure main steam valve 1 position feedback is closed; (2) High-pressure main steam valve 1 closing time is OK; (3) Combined steam valve 1 test is put into operation; S6: Reset the high-pressure main steam valve 1 shutoff solenoid valve 1, and the high-pressure main steam valve 1 directional valve loses power; Feedback conditions are met: (1) High-pressure main steam valve 1 position feedback is closed; (2) High-pressure main steam valve 1 closing time is OK; (3) Combined steam valve 1 test is put into operation; S7: Actuate high-pressure main steam valve 1 to shut off solenoid valve 2; Feedback conditions are met: (1) High-pressure main steam valve 1 position feedback is closed; (2) High-pressure main steam valve 1 closing time is OK; (3) Combined steam valve 1 test is put into operation; S8: Increase the valve limit of control valve 1 to 105% at a certain slope; Feedback conditions are met: (1) High-pressure regulating valve 1 position feedback is fully opened; (2) Combined steam valve 1 test is put into operation; S9: Activate high-pressure regulating valve 1 to shut off solenoid valve 1; Feedback conditions are met: (1) High-pressure regulating valve 1 position feedback is closed; (2) High-pressure regulating valve 1 valve limit = 0%; (3) Combined steam valve 1 test is put into operation; S10: Reset high-pressure regulating valve 1 to shut off solenoid valve 1 and increase the high-pressure regulating valve 1 valve limit = 105%; Feedback conditions are met: (1) High-pressure regulating valve 1 position feedback is fully opened; (2) Combined steam valve 1 test is put into operation; S11: Activate high-pressure regulating valve 1 to cut off solenoid valve 2; Feedback conditions are met: (1) High-pressure regulating valve 1 position feedback is closed; (2) High-pressure regulating valve limit = 0%; (3) Combined steam valve 1 test is put into operation; The test procedure is completed.

[0017] Preferably, after the self-diagnosis includes the test step, it also includes a test reset step: Logic modification: FS-SD command signal activates the walking program, and no logic modification or screen display is performed on empty steps; S1': Reset the high-pressure main steam valve 1 shutoff solenoid valve 2, and the high-pressure main steam valve 1 directional valve loses power; Feedback conditions are met: (1) High-pressure main steam valve 1 position feedback is fully opened; (2) Combined steam valve 1 test is put into operation; S2': reset high-pressure regulating valve 1 to shut off solenoid valve 2 and increase the high-pressure regulating valve 1 valve limit = 105%; Feedback conditions are met: (1) High-pressure regulating valve 1 position feedback is not fully closed; (2) High-pressure regulating valve 1 valve limit = 105%; (3) Combined steam valve 1 test is put into operation; S3': empty instruction; The feedback conditions are all met: (1) High-pressure regulating valve 2 valve limit = 105%; (2) High-pressure regulating valve 2 valve limit = 105%; (3) Medium-pressure regulating valve 2 valve limit = 105%, (4) Medium-pressure regulating valve 2 valve limit = 105%.

[0018] The advantages of the present invention are: The diagnostic method of the present invention establishes a control loop fault self-diagnosis screen that displays the step number of the interrupted steam turbine main engine valve activity test and the cause of the fault in that step. This reduces operators' reliance on professional technicians and the technical requirements of professional technicians, helping operators to promptly and accurately identify problems and take preventive measures to prevent further escalation of the fault. This improves fault handling efficiency and unit safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The present invention will be further described below with reference to the accompanying drawings and embodiments: Figure 1 Added the new MAA 1 high pressure valve A diagnostic screen; Figure 2 Added the MAA 2 high pressure valve A diagnostic screen; Figure 3 Added the MAA 3 high pressure valve A diagnostic screen; Figure 4 Added the new MAA 4 high pressure valve A diagnostic screen; Figure 5 The walking feedback condition is not satisfied condition memory logic diagram established by the present invention; Figure 6 The feedback condition of step 3 of the embodiment; Figure 7 The feedback condition of the instruction in step 5 of the embodiment; Figure 8 This is the instruction feedback condition in step 6 of the embodiment; Figure 9 This is the instruction feedback condition in step 7 of the embodiment; Figure 10 This is the instruction feedback condition in step 8 of the embodiment; Figure 11 This is the instruction feedback condition in step 9 of the embodiment; Figure 12This is the instruction feedback condition in step 10 of the embodiment; Figure 13 This is the instruction feedback condition in step 11 of the embodiment; Figure 14 This is the instruction feedback condition in step 51 of the embodiment; Figure 15 The feedback condition of step 52 in the embodiment; Figure 16 This is the instruction feedback condition for step 56 in the embodiment. DETAILED DESCRIPTION

[0020] The steam turbine main engine combined with the valve activity test control loop fault self-diagnosis method of the present invention comprises: like Figure 1-4 As shown, a fault self-diagnosis screen is established: the first column displays the interrupted steps, followed by the interruption conditions. Test steps are displayed in red to indicate interrupted steps. If the feedback conditions are met (normal), the screen displays red; if the feedback conditions are not met (fault), the screen displays green. An alarm reset button is located in the upper right corner of the screen. Figure 1-4 The newly added diagnostic screens are: MAA 1 High-pressure steam valve A; MAA 2 High-pressure steam valve B; MAB 1 Medium-pressure steam valve A; MAB 2 Medium-pressure steam valve B.

[0021] like Figure 5 As shown, the memory logic for the unsatisfied walking feedback condition is established, including: Step control logic FS-OP principle triggering conditions: When the previous step instruction is completed, the current step control instruction is activated. When the trigger condition is "1", the CMD instruction output is "1", and the relevant equipment is driven according to the control logic. T_WAIT is the shortest execution cycle of the waiting time of this step. Within the shortest cycle, WT output is "1", T_MON is the monitoring time of this step, and when the monitoring time is up, the CMD instruction is reset to "0". CRIT is the passing condition of this step. When WT is "1" and the feedback condition is "1", this step is completed and triggers NEXT to "1", and continues to trigger the next step instruction. When all test logics are completed, the test recovery logic FS-SD program is executed; if the feedback condition is not met, the walking logic is interrupted and the test program is directly cut off.

[0022] The logic fault memory function records the feedback condition when the step control instruction is activated, that is, the condition is "1". The principle is as follows:

[0023] During the test, state 1: when WT is "1", the feedback condition is "1", the record is displayed as "1", and the screen is displayed in red.

[0024] State 2: When WT is "1", the feedback condition is "0", the record display is "0", and the screen displays green.

[0025] Test step fault record: that is, when the current step instruction CMD sends "1", the screen step displays red. This signal needs to be reset to the previous step when the next step instruction CMD sends "1", and the screen displays green. If the feedback condition of this step is not met, the next step instruction CMD is not triggered, and the screen displays red to indicate an interrupted step.

[0026] If any condition is not met, the feedback condition on the screen will be displayed in green. Since the test is interrupted, there is no reset for the next step instruction. Other conditions that are met will be displayed in red. After all feedback conditions are met, the next trigger condition is triggered, and the next CMD instruction clears the feedback condition of the previous step to "0" and the screen feedback condition displays green.

[0027] That is, when the screen step is displayed in red, it indicates the step where the test is interrupted. In the content column of the step, red indicates that the condition is met, and green indicates that it is not met.

[0028] When the fault is handled, press the "alarm reset button" to clear the alarm before the next test can be carried out.

[0029] Logic modification: The FS-OP instruction signal activates the walking program, and the empty steps do not make logic modifications and screen displays.

[0030] Steps 1 and 2: empty instructions; Step 3: Instruction: Reduce the high-pressure valve 1 limit to 0% with a certain slope; Feedback conditions are met: (1) High-pressure valve 1 position feedback is closed; (2) High-pressure valve 1 valve limit = 0%; (3) Combined valve 1 test is put into operation, such as Figure 6 shown.

[0031] Step 4: Empty instruction; Step 5: Instruction: Actuate high-pressure main steam valve 1 to shut off solenoid valve 1; Feedback conditions are met: (1) High-pressure main steam valve 1 position feedback is closed; (2) High-pressure main steam valve 1 closing time is OK; (3) Joint steam valve 1 test is put into operation, such as Figure 7 shown.

[0032] Step 6: Command: Reset the high-pressure main steam valve 1 shutoff solenoid valve 1, and the high-pressure main steam valve 1 directional valve loses power; Feedback conditions are met: (1) High-pressure main steam valve 1 position feedback is closed; (2) High-pressure main steam valve 1 closing time is OK; (3) Joint steam valve 1 test is put into operation, such as Figure 8 shown.

[0033] Step 7: Instruction: Actuate high pressure main steam valve 1 to shut off solenoid valve 2 Feedback conditions are met: (1) High-pressure main steam valve 1 position feedback is closed; (2) High-pressure main steam valve 1 closing time is OK; (3) Joint steam valve 1 test is put into operation, such as Figure 9 shown.

[0034] Step 8: Instruction: Increase the valve limit of valve 1 to 105% at a certain slope Feedback conditions are met: (1) High-pressure regulating valve 1 position feedback is fully opened; (2) Combined steam valve 1 test is put into operation, such as Figure 10 shown.

[0035] Step 9: Instruction: Activate high-pressure regulating valve 1 to shut off solenoid valve 1 Feedback conditions are met: (1) High-pressure regulating valve 1 position feedback is closed; (2) High-pressure regulating valve 1 valve limit = 0%; (3) Combined steam valve 1 test is put into operation, such as Figure 11 shown.

[0036] Step 10: Command reset high pressure regulating valve 1 to shut off solenoid valve 1 and increase high pressure regulating valve 1 valve limit = 105% Feedback conditions are met: (1) High-pressure regulating valve 1 position feedback is fully opened; (2) Combined steam valve 1 test is put into operation, such as Figure 12 shown.

[0037] Step 11: Instruction: Actuate high-pressure regulating valve 1 to shut off solenoid valve 2 Feedback conditions are met: (1) High-pressure regulating valve 1 position feedback is closed; (2) High-pressure regulating valve limit = 0%; (3) Combined steam valve 1 test is put into operation, such as Figure 13 shown.

[0038] The test procedure is completed.

[0039] Self-diagnosis includes the following steps after the test is completed: Logic modification: FS-SD command signal activates the walking program, and no logic modification or screen display is performed on empty steps; Step 51: Command: Reset the high-pressure main steam valve 1 to shut off the solenoid valve 2, and the high-pressure main steam valve 1 directional valve loses power. Feedback conditions are met: (1) High-pressure main steam valve 1 position feedback is fully opened; (2) Joint steam valve 1 test is put into operation, such as Figure 14 shown.

[0040] Step 52: Command: Reset high-pressure regulating valve 1 to shut off solenoid valve 2 and increase high-pressure regulating valve 1 valve limit = 105%; Feedback conditions are met: (1) High pressure regulating valve 1 position feedback is not closed enough; (2) High pressure regulating valve 1 valve limit = 105%; (3) Combined steam valve 1 test is put into operation, such as Figure 15 shown.

[0041] Step 56: Empty instruction; The feedback conditions are all satisfied: (1) High pressure regulating valve 2 valve limit = 105%; (2) High pressure regulating valve 2 valve limit = 105%; (3) Medium pressure regulating valve 2 valve limit = 105%, (4) Medium pressure regulating valve 2 valve limit = 105%, such as Figure 16 shown.

[0042] The present invention helps operating personnel to promptly and accurately judge problems and take measures to prevent faults from expanding. Click on the self-diagnosis screen of the control loop fault of the turbine main engine valve ATT (combined valve) valve activity test system to display the step number of the interruption of the turbine main engine valve activity test and the cause of the fault in the step. It reduces the dependence of operating personnel on professional technicians and at the same time reduces the technical requirements of professional technicians, which can help operating personnel to promptly and accurately judge problems and take measures to prevent faults from expanding. Improve the efficiency of fault handling and improve the safety of the unit. The DEH control system of a certain unit uses this control software to monitor the process of the turbine main engine valve ATT (combined valve) valve activity test and to provide data feedback after a fault interruption occurs. It automatically displays the steps of the interruption and the cause of the interruption. The software is used normally.

[0043] The above embodiments are intended only to illustrate the technical concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand the contents of the present invention and implement them accordingly. They are not intended to limit the scope of protection of the present invention. Any modifications made based on the spirit of the main technical solution of the present invention shall be included in the scope of protection of the present invention.

Claims

1. A method for self-diagnosis of a control circuit fault in a steam turbine main engine combined with a valve activity test, characterized in that: include: Establish fault self-diagnosis screen: display interruption steps and interruption conditions; Establish the memory logic for unsatisfied walking feedback conditions, including: Triggering conditions of the step control logic FS-OP principle: When the previous step instruction is completed, the current step control instruction is activated. When the trigger condition is "1", the CMD instruction output is "1", and the relevant equipment is driven according to the control logic. T_WAIT is the shortest execution cycle of the waiting time of this step. Within the shortest cycle, WT output is "1", T_MON is the monitoring time of this step, and when the monitoring time is up, the CMD instruction is reset to "0". CRIT is the passing condition of this step. When WT is "1" and the feedback condition is "1", this step is completed and triggers NEXT to "1", and continues to trigger the next step instruction. When all test logics are completed, the test recovery logic FS-SD program is executed; if the feedback condition is not met, the walking logic is interrupted and the test program is directly cut off; Logical fault memory function: When the step control instruction is activated, the feedback condition is satisfied, that is, the condition is "1" and recorded; Test step fault record: that is, when the current step command CMD sends "1", the signal needs to be reset to the previous step when the next step command CMD sends "1"; if the feedback condition of the current step is not met, the next step command CMD is not triggered and the step is interrupted; If any condition is not met, the feedback condition on the screen will be displayed in green. Since the test is interrupted, there is no reset for the next step instruction. Other conditions that are met will be displayed in red. After all feedback conditions are met, the next trigger condition is triggered. The next CMD instruction clears the feedback condition of the previous step to "0" and the screen feedback condition displays green; That is, when the screen step is displayed in red, it means the step where the test is interrupted. In the content column of the step, red means the condition is met, and green means it is not met. When the fault is handled, press the "alarm reset button" to clear the alarm before the next test can be carried out.

2. The method for self-diagnosis of control loop faults in a steam turbine main engine combined with valve activity test according to claim 1, characterized in that: Self-diagnosis includes the following test steps: Logic modification: FS-OP command signal activates the walking program, and no logic modification or screen display is performed on empty steps; S1, S2: empty steps; S3: Reduce the valve limit of high-pressure valve 1 to 0% with a certain slope; Feedback conditions are met: (1) High-pressure valve 1 position feedback is closed; (2) High-pressure valve 1 valve limit = 0%; (3) Combined valve 1 test is put into operation; S4: empty step; S5: Actuate high-pressure main steam valve 1 to shut off solenoid valve 1; Feedback conditions are met: (1) High-pressure main steam valve 1 position feedback is closed; (2) High-pressure main steam valve 1 closing time is OK; (3) Combined steam valve 1 test is put into operation; S6: Reset the high-pressure main steam valve 1 shutoff solenoid valve 1, and the high-pressure main steam valve 1 directional valve loses power; Feedback conditions are met: (1) High-pressure main steam valve 1 position feedback is closed; (2) High-pressure main steam valve 1 closing time is OK; (3) Combined steam valve 1 test is put into operation; S7: Actuate high-pressure main steam valve 1 to shut off solenoid valve 2; Feedback conditions are met: (1) High-pressure main steam valve 1 position feedback is closed; (2) High-pressure main steam valve 1 closing time is OK; (3) Combined steam valve 1 test is put into operation; S8: Increase the valve limit of control valve 1 to 105% at a certain slope; Feedback conditions are met: (1) High-pressure regulating valve 1 position feedback is fully opened; (2) Combined steam valve 1 test is put into operation; S9: Activate high-pressure regulating valve 1 to shut off solenoid valve 1; Feedback conditions are met: (1) High-pressure regulating valve 1 position feedback is closed; (2) High-pressure regulating valve 1 valve limit = 0%; (3) Combined steam valve 1 test is put into operation; S10: Reset high-pressure regulating valve 1 to shut off solenoid valve 1 and increase the high-pressure regulating valve 1 valve limit = 105%; Feedback conditions are met: (1) High-pressure regulating valve 1 position feedback is fully opened; (2) Combined steam valve 1 test is put into operation; S11: Activate high-pressure regulating valve 1 to cut off solenoid valve 2; Feedback conditions are met: (1) High-pressure regulating valve 1 position feedback is closed; (2) High-pressure regulating valve limit = 0%; (3) Combined steam valve 1 test is put into operation; The test procedure is completed.

3. The method for self-diagnosis of control loop faults in a steam turbine main engine combined with valve activity test according to claim 1, characterized in that: Self-diagnosis includes the following steps after the test is completed: S1': Reset the high-pressure main steam valve 1 shutoff solenoid valve 2, and the high-pressure main steam valve 1 directional valve loses power; Feedback conditions are met: (1) High-pressure main steam valve 1 position feedback is fully opened; (2) Combined steam valve 1 test is put into operation; S2': reset high-pressure regulating valve 1 to shut off solenoid valve 2 and increase the high-pressure regulating valve 1 valve limit = 105%; Feedback conditions are met: (1) High-pressure regulating valve 1 position feedback is not fully closed; (2) High-pressure regulating valve 1 valve limit = 105%; (3) Combined steam valve 1 test is put into operation; S3': empty instruction; The feedback conditions are all met: (1) High-pressure regulating valve 2 valve limit = 105%; (2) High-pressure regulating valve 2 valve limit = 105%; (3) Medium-pressure regulating valve 2 valve limit = 105%, (4) Medium-pressure regulating valve 2 valve limit = 105%.

Images