A method for fault monitoring of steam turbine EH system

Abstract

A method for fault monitoring of a steam turbine EH system belongs to the field of control. Existing methods cannot monitor EH system faults online. This invention involves connecting three pipelines in parallel between the EH oil tank and the EH oil header. A main servo pump group, a slave servo pump group, and a standby pump group are installed on each of these three pipelines. Corresponding sensors are installed on each of the three pipelines and the EH oil header. When any of the main servo pump group, slave servo pump group, or standby pump group is running, the intelligent front-end detects whether the running pump group has a fault based on the sensor output data on the pipeline where the running pump group is located. It also detects whether the pump interlock pressure switch has a fault based on the pressure sensor output data on the EH oil header; it also detects whether there is an oil leak in the EH system based on the sensor output data on the EH oil header; and it detects the volumetric capacity of the corresponding main servo pump group or slave servo pump group based on the sensors on the EH oil header, as well as the rated displacement and motor speed of the main servo pump group or slave servo pump group. This invention is used for online fault monitoring.

Description

Technical Field

[0001] This invention relates to EH system control methods and belongs to the field of control. Background Technology

[0002] The EH oil supply unit is the power source for the turbine regulation and safety system (hereinafter referred to as the EH system). It provides power for the normal operation of the EH system and supplies the actuators with a working medium at suitable temperature and pressure. Currently, commonly used EH oil supply units employ constant-pressure variable displacement piston pumps, employing a mechanical automatic pressure regulation method. Two pump sets are arranged, one for operation and one for standby. When the main pipe pressure falls below a certain value (usually 0.8 times the system set pressure), the standby pump is interlocked and activated, controlling both pumps to operate simultaneously to supplement flow and stabilize pressure. However, in actual system operation, when pump malfunctions occur, there are few intermediate measurement points available for status analysis, and the EH system itself is relatively complex, making it impossible to monitor the specific causes of faults online. This leads to maintenance personnel being unable to promptly detect faults in the EH pump sets. Typically, triggering the interlock to activate the standby pump is considered a fault in the EH system (pump sets and actuators). When pump malfunctions occur, maintenance personnel can only intervene manually, retrieving data and coordinating with manufacturers and experts in related fields for manual analysis. This method is time-consuming, prone to problems, and carries significant risks. Therefore, both online processing and waiting-for-shutdown processing carry certain risks and are not conducive to the safe and stable operation of the EH system. There is a lack of effective means to monitor EH system faults online. Summary of the Invention

[0003] The purpose of this invention is to solve the problem of the inability to monitor EH system faults online, and to propose a fault monitoring method for steam turbine EH systems.

[0004] A method for fault monitoring of a steam turbine EH system, the method comprising the following:

[0005] Step 1: Connect three pipelines in parallel between the EH oil tank and the EH oil header. Install the main servo pump set, the slave servo pump set, and the standby pump set on the three pipelines respectively. Install one flow sensor and one pressure sensor on each of the three pipelines and the EH oil header. Install one current sensor and one speed sensor on each of the main servo pump set, the slave servo pump set, and the standby pump set. Install a liquid level sensor on the EH oil tank.

[0006] Step 2: When any of the main servo pump group, slave servo pump group, and standby pump group is running, the intelligent front end detects whether the running pump group has a fault based on the output data of the flow sensor, pressure sensor, current sensor, and speed sensor on the pipeline where the running pump group is located.

[0007] The intelligent front end detects whether the pump interlock pressure switch is malfunctioning based on the pressure sensor output data on the EH oil header; the intelligent front end also detects whether the EH system is leaking oil based on the pressure sensor and flow sensor output data on the EH oil header.

[0008] The intelligent front end detects the volumetric capacity of the corresponding main servo pump group or slave servo pump group based on the flow sensor on the EH oil header, as well as the rated displacement and motor speed of the main servo pump group or slave servo pump group.

[0009] Preferably, step 2 further includes: the intelligent front end determines, based on the pressure data on the EH oil header and the current data output by the main servo pump group or the slave servo pump group, whether the slave servo pump group is in operation when the main servo pump group is working, whether the main servo pump group is in operation when the slave servo pump group is working, and whether the slave servo pump group is disconnected when the main servo pump group and the slave servo pump group are running in parallel, based on the pressure data on the EH oil header and the current data of the running main servo pump group or the slave servo pump group.

[0010] The process of determining whether the slave servo pump group is in operation when the main servo pump group is working, and whether the main servo pump group is in operation when the slave servo pump group is working:

[0011] When either the main servo pump group or the slave servo pump group is running, the intelligent front end receives the EH oil header pressure P0 and the running pump group current i. k Simultaneously satisfying P0 < P 0初 ×0.975 and i k ≥0.95×i max When or satisfying i k <0.95×i max and P0 < P 0初 At the same time, the main servo pump group and other pump groups in the slave servo pump group are started, realizing the parallel operation of the main servo pump group and the slave servo pump group, where P 0初 i represents the initial pressure value of the EH oil header. max Rated current of the main servo pump set and the slave servo pump set;

[0012] The process of determining whether to disconnect from the servo pump unit:

[0013] After the main servo pump group and the slave servo pump group have been running in parallel for at least 10 minutes, the intelligent front end detects whether P0 > P20 simultaneously. 0初 ×0.975, 0.8×i max >i1+i2 and S 调 <5%, if so, the intelligent front-end control reduces the servo pump group speed n2 to 0 within 10s and disconnects the servo pump group; if not, the main servo pump group and the servo pump group maintain parallel operation, where i1 is the main servo pump group current, i2 is the servo pump group current, and S调 This refers to the changes in valve control commands for the DEH system.

[0014] Preferably, in step 2, the process of detecting whether the pump interlock pressure has malfunctioned is as follows:

[0015] The pump interlock pressure switch's operating value is monitored via a transmitter. When P... 0初 ×0.85≥Action Value≥P 0初 When ×0.75, where P 0初 If the initial pressure value of the EH oil header is used, the pump interlock pressure switch is determined to be normal; otherwise, the pump interlock pressure switch is determined to be faulty.

[0016] Preferably, in step 2, the process of detecting whether the main servo pump group or the slave servo pump group in the operating pump group has malfunctioned is as follows:

[0017] The intelligent front end obtains the performance F1 of the main servo pump group or the slave servo pump group based on the motor speed, outlet pressure and motor current received in real time when the main servo pump group or the slave servo pump group is working.

[0018] When the performance F1 of the main servo pump group or the slave servo pump group is equal to the initial performance F1 set... 0 When the efficiency is ≤50%, the intelligent front end outputs the first alarm signal to the DEH or DCS system, prompting the replacement of the main servo pump group or the slave servo pump group;

[0019] When 50% < the performance F1 of the main servo pump group or the slave servo pump group / the set initial performance F1 0 When the efficiency is ≤70%, the intelligent front end will output a second alarm signal to the DEH or DCS system, and start the big data analysis platform to determine whether the main servo pump group or the slave servo pump group is faulty. If so, it will prompt that the main servo pump group or the slave servo pump group should be replaced. If not, the alarm information will be cleared.

[0020] When the performance F1 of the main servo pump group or the slave servo pump group is equal to the initial performance F1 set... 0 If the percentage is greater than 70%, the main servo pump group or the slave servo pump group is considered to be normal.

[0021] Preferably, in step 2, the volumetric capacity of the main servo pump group or the slave servo pump group is detected, and the specific process is as follows:

[0022] When the main servo pump group or the slave servo pump group is working, the intelligent front end determines the EH oil header flow rate Q0 and the rated displacement V of the main servo pump group or the slave servo pump group based on the received EH oil header flow rate Q0 and the rated displacement V of the main servo pump group or the slave servo pump group. g The motor speed n of the main servo pump group or the slave servo pump group i Where i is 1 or 2, n1 represents the speed of the main servo pump group motor, and n2 represents the speed of the slave servo pump group motor. This determines whether to replace the main or slave servo pump group; when 0.7 ≤ Q0 / (ni ×V g When Q0 < 0.9, the intelligent front-end will display an abnormal volumetric capacity of either the main servo pump group or the slave servo pump group; when Q0 / (n) is satisfied... i ×V g When Q0 / (n) < 0.7, the intelligent front-end sends an alarm to the DEH or DCS system, prompting the replacement of the main servo pump group or the slave servo pump group; when Q0 / (n) is satisfied... i ×V g When the value is ≥0.9, the volumetric capacity of the main servo pump group or the slave servo pump group is considered to be normal.

[0023] Preferably, in step 2, the process of detecting whether the standby pump set in the operating pump set has malfunctioned is as follows:

[0024] Collect the EH oil header flow rate Q0, and the rated displacement V of any one of the main servo pump group and slave servo pump group. g The motor speed n of either the main servo pump group or the slave servo pump group. i Calculate the performance index F3 of the standby pump group based on the EH oil main pipe pressure P0 and the EH standby pump motor current i3. When 50% < F3 / F3 0 When the efficiency is ≤70%, the intelligent front-end outputs the first alarm signal to the DEH or DCS system, activates the big data analysis platform to determine if the standby pump set is faulty. If so, the standby pump set is replaced; otherwise, the alarm information is cleared. When the efficiency is ≥50%, F3 / F3 0 When this happens, the intelligent front-end outputs a second alarm signal to the DEH or DCS system, prompting the replacement of the standby pump unit; when F3 / F3 0 When the efficiency is >70%, the standby pump set is considered normal, including F3. 0 The initial values ​​of the performance indicators of the standby pump set are i, which is 1 or 2. n1 represents the speed of the main servo pump set motor, and n2 represents the speed of the slave servo pump set motor.

[0025] Preferably, the performance index F3 of the standby pump set is expressed as:

[0026] F3=(Q0-n i ×V g )×P0 / i3.

[0027] Preferably, the process for detecting whether the EH system has an oil leak is as follows:

[0028] Step C1: Collect the current EH oil header flow rate Q0. When ΔQ0 / Q0 < 20%, the EH system is considered normal; when ΔQ0 / Q0 ≥ 20%, proceed to step C2.

[0029] Step C2: Determine the change range S of the control valve command in the DEH system. 调Is it greater than or equal to 10%? If yes, the EH system is considered normal. If not, proceed to step C3.

[0030] Step C3: Determine whether ΔP0 / P0 < 10%. If yes, determine that the EH system is normal. If no, proceed to step C4.

[0031] Step C5: Check if ΔL / L < 10% occurs within 10 minutes. If yes, the EH system is considered normal. If no, proceed to step C6.

[0032] Step C6: The intelligent front end sends an alarm to the DEH or DCS system, and the big data analysis platform is activated to determine whether an oil leak has occurred in the EH system. If so, prompt for handling; if not, clear the alarm signal. Here, P0 is the current EH oil header pressure, ΔP0 is the difference between the current EH oil header pressure and the initial EH oil header pressure, and ΔQ0 is the difference between the current EH oil header flow rate and the initial EH oil header flow rate.

[0033] Preferably, step 2 further includes: periodically controlling the operation of the standby pump group to check whether the standby pump group is faulty.

[0034] Preferably, the operation of the standby pump unit is controlled, and the specific process is as follows:

[0035] When the main servo pump unit is running and i1 < i max ×0.8, i2=0, i3=0, S 调 When <5% and ΔL / L <5%, start the standby pump group. After the motor current i1 of the main servo pump group and the motor current i3 of the standby pump group are both stable, detect the speed n1 of the main servo pump group, calculate the deceleration rate that will reduce the speed to 0 within 5 minutes, and continuously adjust and reduce n1 according to the deceleration rate until n1 is zero.

[0036] After n1 decreases to 0 and is maintained at that level for 1 minute, the main servo pump unit is restarted until the speed n1 stabilizes and Q0 < V. g ×n max ×0.8、S 调 When the percentage is <10% and ΔL / L <10%, the standby pump unit is disconnected, where i2 is the motor current of the servo pump unit, and S 调 For changes in the DEH system control valve command, L is the current EH tank level, ΔL is the difference between the current and initial EH tank levels, Q0 is the EH oil header flow rate, and V... g The rated displacement of the master servo pump set and the slave servo pump set, n max The maximum speed of the master servo pump set and the slave servo pump set.

[0037] The beneficial effects of this invention are:

[0038] This invention adds multiple sensors to the conventional EH oil supply unit structure and incorporates a servo pump group, utilizing the existing liquid level sensor. It also features an independent intelligent front-end for control and online monitoring. To ensure system safety, the backup pump group still employs a mechanically pressure-controlled constant-pressure variable displacement piston pump, started via a pressure switch hard interlock as a final safety guarantee. The intelligent front-end performs classification calculations and status analysis according to different system states, determining the equipment's operating status and implementing functions such as classified control, notification, reminders, and alarms to achieve intelligent operation and maintenance. This invention can diagnose pump group failures, damage, and EH system oil leaks, thereby determining whether the EH oil supply unit is operating normally.

[0039] This invention can monitor and perform calculations on key parameters of the turbine EH oil supply unit through an intelligent front-end and multiple sensors, and select a control strategy based on the changes in the collected and calculated data.

[0040] This invention can control the servo-type master-slave pump set of the turbine EH oil supply unit, start and stop the slave pump according to the changes in system flow and pressure, and ensure that the oil supply unit can normally provide the EH system with a working medium of appropriate flow and stable pressure.

[0041] This invention can control the standby pump of the steam turbine EH oil supply unit to start automatically and in a timely manner according to the interlock conditions, and sets the conditions for disconnection to ensure the stable operation of the oil supply unit.

[0042] This invention can periodically start and stop the standby pump of the turbine EH oil supply unit online, ensuring that it is in a hot standby state while checking its performance.

[0043] This invention can check the performance of the standby pump interlocking start pressure switch of the steam turbine EH oil supply unit online, whether there is a potential for pump damage, and provide solutions for the fault.

[0044] This invention can check the performance of the servo-type master-slave pump set of the steam turbine EH oil supply unit online, determine whether there is a potential for damage to the pump set, and provide a solution based on the fault.

[0045] This invention can check the volumetric capacity of the servo-type master-slave servo pump set of the steam turbine EH oil supply unit online, determine whether there is a potential for damage to the pump set, and provide a solution based on the fault.

[0046] This invention can analyze and calculate based on the data from the start-up inspection of the standby pump of the steam turbine EH oil supply unit to determine whether there is a potential for damage to the pump set, and provide a solution based on the fault.

[0047] This invention can determine online whether there is an oil leak in the turbine EH system, and adjust the control strategy of the oil supply unit in addition to alarm reminders to avoid more serious losses such as pump cavitation damage.

[0048] This invention can also be input into the background along with other measuring points of the steam turbine EH system, and comprehensively analyzed through a big data analysis platform to further improve the system's fault diagnosis capabilities, and has a certain degree of scalability. Attached Figure Description

[0049] Figure 1 Schematic diagram of the measuring point layout for the EH oil supply unit;

[0050] Figure 2 Control principle diagram of the main servo pump group, slave servo pump group and standby pump group;

[0051] Figure 3 Flowchart for switching between master and slave servo pump sets;

[0052] Figure 4 Flowchart for the switching on / off process of the standby pump unit;

[0053] Figure 5 Flowchart for performance testing of standby pump units;

[0054] Figure 6 Flowchart for diagnosing pump interlock pressure switch faults;

[0055] Figure 7 Flowchart for performance testing of master or slave servo pump sets;

[0056] Figure 8 Flowchart for detecting the volumetric capacity of the master or slave servo pump set;

[0057] Figure 9 Flowchart for fault diagnosis of standby pump unit;

[0058] Figure 10 This is a flowchart for diagnosing oil leaks in the EH system. Detailed Implementation

[0059] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. 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.

[0060] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0061] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the scope of the invention.

[0062] Example:

[0063] Combination Figure 1 This embodiment describes a fault monitoring method for a steam turbine EH system, the method comprising the following:

[0064] Step 1: Connect three pipelines in parallel between the EH oil tank and the EH oil header. Install the main servo pump set, the slave servo pump set, and the standby pump set on the three pipelines respectively. Install one flow sensor and one pressure sensor on each of the three pipelines and the EH oil header. Install one current sensor and one speed sensor on each of the main servo pump set, the slave servo pump set, and the standby pump set. Install a liquid level sensor on the EH oil tank.

[0065] Step 2: When any of the main servo pump group, slave servo pump group, and standby pump group is running, the intelligent front end detects whether the running pump group has a fault based on the output data of the flow sensor, pressure sensor, current sensor, and speed sensor on the pipeline where the running pump group is located.

[0066] The intelligent front end detects whether the pump interlock pressure switch is malfunctioning based on the pressure sensor output data on the EH oil header; the intelligent front end also detects whether the EH system is leaking oil based on the pressure sensor and flow sensor output data on the EH oil header.

[0067] The intelligent front end detects the volumetric capacity of the corresponding main servo pump group or slave servo pump group based on the flow sensor on the EH oil header, as well as the rated displacement and motor speed of the main servo pump group or slave servo pump group.

[0068] Specifically, this embodiment describes an intelligent control method for the oil supply unit of a steam turbine EH system. The main pump assembly of the original EH oil supply unit is upgraded from a conventional mechanically pressure-controlled constant-pressure variable displacement plunger pump to two electronically pressure-controlled servo pump sets (a main servo pump set and a slave servo pump set). The ratio of the rated flow rate of each of these two electronically pressure-regulated servo pump sets to the rated flow rate of the mechanically pressure-regulated plunger pump should be no less than 0.6 times. Flow measurement points and pressure measurement points are configured on the main pipe of the EH oil supply unit, and pressure measurement points are also set on the output pipeline of each pump set. The intelligent front-end controls the start and stop of the two servo pump sets. Upon receiving instructions from the host computer (DCS or DEH), the servo motor controller is enabled, and the servo pump sets are started and stopped according to the control instructions. The servo motor controller outputs speed and pump motor current information to the intelligent front-end for control decision-making. The intelligent front-end, combined with the system operating status, performs pump set switching, pump set interlocking, and other operations, and performs fault diagnosis and prediction. In addition to making decisions based on fault information, the intelligent front-end can also transmit the equipment operating status to the power plant's DEH or DCS system. To ensure system safety, the backup pump is still a mechanically pressure-controlled constant-pressure variable displacement piston pump, with flow rate, pressure, and pump motor current measuring points installed on the pump unit. This pump unit is started via a pressure switch hard interlock as the final safety guarantee for the system. The arrangement of the equipment and sensors involved in this method is shown in the appendix. Figure 1 As shown.

[0069] Table 1 shows the parameter information for each device code and the specific measured values, constants, and calculated values ​​of the sensors used.

[0070] Table 1. Details of measuring points and other constant physical quantities in a fault monitoring method for a steam turbine EH system.

[0071]

[0072]

[0073] The parameters in Table 1 are measured and recorded in real time to form a system database for status analysis.

[0074] When the EH oil supply unit is operating, two servo pump sets provide the required flow and pressure to the system. The intelligent front-end controls the servo pump set motor drivers to start and stop the servo motors. The master / slave relationship is switched monthly. For example, in January, the master servo pump set is the master pump; when the system flow is insufficient or the pressure drops, the slave servo pump set is activated to supplement the flow and pressure. In February, the slave servo pump set becomes the master pump, and when the system flow is insufficient or the pressure drops, the master servo pump set is activated to supplement the flow and pressure. This achieves an even distribution of the working time of the two pump sets, ensuring a relatively even utilization rate for both servo pump sets. In any situation, if the EH oil header pressure drops to the emergency connection pump pressure value, the standby pump motor is interlocked and activated via a local hard-wired circuit, putting the standby pump set into operation. Simultaneously, every two months, after the master and slave servo pump sets have been switched once, the system switches back to the master servo pump set when the DEH system valve control command S is executed. 调 When the fluctuation is less than 5%, indicating very stable system operation and minimal changes in the valve position, the EH system standby pump is started and runs in parallel with the main servo pump group for approximately 2 hours. The flow rate and current correspondence of the pump group are calculated at each measuring point and recorded, then compared with historical data to verify normal operation. The workflow logic diagram at this time is attached. Figure 2 As shown.

[0075] Combination Figure 3 The following describes the logical relationship between two servo pump sets, one master and one slave, when they are operating in a cascading manner to achieve pump interlocking:

[0076] The intelligent front end determines whether the slave servo pump group should be put into operation when the main servo pump group is working, and whether the main servo pump group should be put into operation when the slave servo pump group is working, based on the pressure data on the EH oil header and the current data output by the main servo pump group or the slave servo pump group. Furthermore, when the main servo pump group and the slave servo pump group are running in parallel, it determines whether to disconnect the slave servo pump group based on the pressure data on the EH oil header and the current data of the running main servo pump group or the slave servo pump group.

[0077] The process of determining whether the slave servo pump group is in operation when the main servo pump group is working, and whether the main servo pump group is in operation when the slave servo pump group is working:

[0078] When either the main servo pump group or the slave servo pump group is running, the intelligent front end receives the EH oil header pressure P0 and the running pump group current i. k Simultaneously satisfying P0 < P 0初 ×0.975 and i k ≥0.95×i max When or satisfying i k <0.95×i max and P0 < P 0初At the same time, the main servo pump group and other pump groups in the slave servo pump group are started, realizing the parallel operation of the main servo pump group and the slave servo pump group, where P 0初 i represents the initial pressure value of the EH oil header. max Rated current of the main servo pump set and the slave servo pump set;

[0079] The process of determining whether to disconnect from the servo pump unit:

[0080] After the main servo pump group and the slave servo pump group have been running in parallel for at least 10 minutes, the intelligent front end detects whether P0 > P20 simultaneously. 0初 ×0.975, 0.8×i max >i1+i2 and S 调 <5%, if so, the intelligent front-end control reduces the servo pump group speed n2 to 0 within 10s and disconnects the servo pump group; if not, the main servo pump group and the servo pump group maintain parallel operation, where i1 is the main servo pump group current, i2 is the servo pump group current, and S 调 This refers to the changes in valve control commands for the DEH system.

[0081] Specifically, when the EH system is working normally, the main servo pump set operates normally. When the system pressure decreases, the speed increases accordingly to achieve the constant pressure control target. At this time, the speed needs to satisfy the following relationship (taking servo pump set No. 1 as the main pump as an example): n1=Q0 / V g n1 is the main servo pump unit speed;

[0082] The system's control objective is to keep the pressure constant, and the target speed n1 needs to meet the flow requirements. The driver aims for constant pressure control and controls speed changes to achieve closed-loop control.

[0083] When the pump current i1 rises to 95% of imax, the power output of the main servo pump set is basically at its maximum. At this time, the safety margin of pump set 1 is already very low. Therefore, if the pressure continues to drop and the oil pressure in the EH oil header drops below 97.5% of P0, the slave servo pump set needs to be started immediately to replenish the system with pressure and flow.

[0084] When the speed is increasing but has not reached nmax, and the pump current has not reached 95% of imax, but the system pressure has dropped below 90%, the servo pump group needs to be started immediately to replenish the system with pressure and flow.

[0085] After the pump interlock is completed, it should run for at least 10 minutes. When the EH system restarts and stabilizes, and P0 is greater than 97.5% of the initial P0, the DEH system valve control command S should be executed. 调 When the fluctuation value is <5% and the intelligent front-end does not diagnose other faults, and the condition of 0.8×i is met, maxWhen the value is greater than i1+i2, the interlocking state of the pump group can be canceled, and it can be switched to single pump operation.

[0086] When this command is executed, the main servo pump group continues to run, and the intelligent front end maintains the pump group in a pressure closed-loop control state. The slave servo pump group delays for 10 seconds, and its speed is continuously reduced according to a certain deceleration rate until the pump current stops. At this time, P0 should remain basically stable. If P0 falls below 95% of its normal value during adjustment, the control system needs to pause the adjustment for 10 minutes, maintain dual-pump operation, and continue until it stabilizes again before disconnecting the slave servo pump group. See the attached flowchart for the specific operation process. Figure 3 As shown. Figure 3 It can realize fully automatic start-up and shutdown and intelligent operation and maintenance of the main servo pump set.

[0087] Combination Figure 4 This section explains the logical relationship between the interlocking activation and deactivation of the standby pump:

[0088] Triggering the pump interlock pressure switch, the main servo pump group and the slave servo pump group start simultaneously, when P0 ≥ P 0初 When P0 < P, the standby pump unit must not be started. 0初 When the value reaches ×0.8, the standby pump group is started, and the intelligent front end sends an alarm to the DEH or DCS system. The big data analysis platform is then activated to determine if a fault has occurred. If so, the main servo pump group, the slave servo pump group, and the standby pump group are kept running. If not, the standby pump group is shut down.

[0089] Specifically, during any operation, standby pump group 3 remains on standby. Once the pump pressure switch (set to 0.8 of P0's initial value) is triggered, the standby pump group is activated. After the standby pump is engaged, the intelligent front-end sends an alarm to the DCS or DEH system and requests manual intervention. If a big data analysis system is available, it is simultaneously activated for analysis. After maintenance personnel combine the fault analysis from the intelligent front-end (and, if applicable, the fault analysis from the big data analysis system), and retrieve system data for comprehensive fault analysis and processing, and confirm that the EH system has returned to normal operation, with the servo pump group normally engaged and operating in a master-slave configuration, the standby pump is manually disconnected to restore the system to normal. See the attached flowchart for the specific operation process. Figure 4 As shown.

[0090] Combination Figure 5 The logical relationship for the periodic inspection of standby pump sets is explained below:

[0091] When the main servo pump unit is running and i1 < i max ×0.8, i2=0, i3=0, S 调When <5% and ΔL / L <5%, start the standby pump group. After the motor current i1 of the main servo pump group and the motor current i3 of the standby pump group are both stable, detect the speed n1 of the main servo pump group, calculate the deceleration rate that will reduce the speed to 0 within 5 minutes, and continuously adjust and reduce n1 according to the deceleration rate until n1 is zero.

[0092] After n1 decreases to 0 and is maintained at that level for 1 minute, the main servo pump unit is restarted until the speed n1 stabilizes and Q0 < V. g ×n max ×0.8、S 调 When the percentage is <10% and ΔL / L <10%, the standby pump unit is disconnected, where i2 is the motor current of the servo pump unit, and S 调 For changes in the DEH system control valve command, L is the current EH tank level, ΔL is the difference between the current and initial EH tank levels, Q0 is the EH oil header flow rate, and V... g The rated displacement of the master servo pump set and the slave servo pump set, n max The maximum speed of the master servo pump set and the slave servo pump set.

[0093] Specifically, when the master servo pump group and the slave servo pump group complete one round of switching and return to the master servo pump group as the master pump, while the slave servo pump group as the slave pump does not start, and the intelligent front end does not detect any other faults, and i1 < i max ×0.8, i2=0, i3=0, S 调 When the values ​​are <5% and ΔL / L <5%, the standby pump set and the main servo pump set are started to run in parallel to monitor the reliability of the standby pump status. Figure 5 The inspection process ensures that the standby pump is started and stopped regularly and that performance checks are performed.

[0094] Returning the master servo pump group and slave servo pump group to the switching operation state means that the master servo pump group and slave servo pump group return to the master-slave operation logic.

[0095] Combination Figure 6 This section describes how to check if there is a malfunction in the pump interlock pressure on the EH oil header:

[0096] The pump interlock pressure switch's operating value is monitored via a transmitter. When P... 0初 ×0.85≥Action Value≥P 0初 When ×0.75, where P 0初 If the initial pressure value of the EH oil header is used, the pump interlock pressure switch is determined to be normal; otherwise, the pump interlock pressure switch is determined to be faulty.

[0097] Specifically, the pump connection values ​​are monitored via a transmitter. If the EH oil header pressure drop is outside 80±5% of P0 during operation, or if the oil pressure resets after operation but the switch command does not reset, the intelligent front-end will report a fault in the pump connection switch to the DCS or DEH system, requesting manual intervention. When manually disconnecting the switch, the intelligent front-end can be operated to interlock the standby pump control with the P0 value measured by the EH oil header pressure transmitter. The setpoint is when the EH oil header pressure drop is 80% of P0. This continues until the switch is manually reconnected after maintenance, and then the intelligent front-end is operated again to switch the standby pump control loop to pressure switch control. See the attached flowchart for the detailed operation process. Figure 6 As shown. Figure 6 The inspection process ensures that the interlocking pressure switch performance of the standby pump is under monitoring and switches the control loop in case of failure.

[0098] Combination Figure 7 This section describes how to detect faults in the main servo pump group and the slave servo pump group:

[0099] The intelligent front end obtains the performance F1 of the main servo pump group or the slave servo pump group based on the motor speed, outlet pressure and motor current received in real time when the main servo pump group or the slave servo pump group is working.

[0100] When the performance F1 of the main servo pump group or the slave servo pump group is equal to the initial performance F1 set... 0 When the efficiency is ≤50%, the intelligent front end outputs the first alarm signal to the DEH or DCS system, prompting the replacement of the main servo pump group or the slave servo pump group;

[0101] When 50% < the performance F1 of the main servo pump group or the slave servo pump group / the set initial performance F1 0 When the efficiency is ≤70%, the intelligent front end will output a second alarm signal to the DEH or DCS system, and start the big data analysis platform to determine whether the main servo pump group or the slave servo pump group is faulty. If so, it will prompt that the main servo pump group or the slave servo pump group should be replaced. If not, the alarm information will be cleared.

[0102] When the performance F1 of the main servo pump group or the slave servo pump group is equal to the initial performance F1 set... 0 If the percentage is greater than 70%, the main servo pump group or the slave servo pump group is considered to be normal.

[0103] Specifically, the system constantly monitors the working status of the servo pump set to obtain the performance of the master servo pump set or the slave servo pump set.

[0104] Define its initial value F1 0 And when F1 / F1 0When the percentage is less than 70%, an alarm should be sent to the intelligent front-end system. If a big data analysis system is available, it should be activated for fault diagnosis. If not, manual inspection should be requested. If a problem is found, the pump set needs to be replaced. If no problem is found, the corresponding fault information should be cleared in the intelligent front-end system and the DCS system, and the protection between 50% and 70% should be disengaged. When F1 / F1 0 When the pump rate is less than 50%, the intelligent front-end system sends an alarm to the DEH or DCS system, indicating that the pump set should be replaced. After replacing the pump set, the corresponding fault information is cleared in both the intelligent front-end system and the DCS system. See the attached flowchart for the detailed operation process. Figure 7 As shown. Figure 7 The inspection process ensures that the oil supply capacity of the servo-type master-slave pump set is under monitoring, and switches and alarms are triggered in a timely manner in case of failure.

[0105] Combination Figure 8 The volumetric capacity of the main servo pump group or the slave servo pump group is detected. The specific process is as follows:

[0106] When the main servo pump group or the slave servo pump group is working, the intelligent front end determines the EH oil header flow rate Q0 and the rated displacement V of the main servo pump group or the slave servo pump group based on the received EH oil header flow rate Q0 and the rated displacement V of the main servo pump group or the slave servo pump group. g The motor speed n of the main servo pump group or the slave servo pump group i Where i is 1 or 2, n1 represents the speed of the main servo pump group motor, and n2 represents the speed of the slave servo pump group motor. This determines whether to replace the main or slave servo pump group; when 0.7 ≤ Q0 / (n i ×V g When Q0 < 0.9, the intelligent front-end will display an abnormal volumetric capacity of either the main servo pump group or the slave servo pump group; when Q0 / (n) is satisfied... i ×V g When Q0 / (n) < 0.7, the intelligent front-end sends an alarm to the DEH or DCS system, prompting the replacement of the main servo pump group or the slave servo pump group; when Q0 / (n) is satisfied... i ×V g When the value is ≥0.9, the volumetric capacity of the main servo pump group or the slave servo pump group is considered to be normal.

[0107] Specifically, Figure 8 The inspection process ensures that the volumetric capacity of the servo-type master-slave pump set is under monitoring, and switches and alarms are triggered promptly in case of failure.

[0108] Combination Figure 9 The specific procedure for checking whether the standby pump set is faulty is as follows:

[0109] Collect the EH oil header flow rate Q0, and the rated displacement V of any one of the main servo pump group and slave servo pump group. g The motor speed n of either the main servo pump group or the slave servo pump group. iCalculate the performance index F3 of the standby pump group based on the EH oil main pipe pressure P0 and the EH standby pump motor current i3. When 50% < F3 / F3 0 When the efficiency is ≤70%, the intelligent front-end outputs the first alarm signal to the DEH or DCS system, activates the big data analysis platform to determine if the standby pump set is faulty. If so, the standby pump set is replaced; otherwise, the alarm information is cleared. When the efficiency is ≥50%, F3 / F3 0 When this happens, the intelligent front-end outputs a second alarm signal to the DEH or DCS system, prompting the replacement of the standby pump unit; when F3 / F3 0 When the efficiency is >70%, the standby pump set is considered normal, including F3. 0 The initial values ​​of the performance indicators of the standby pump set are i, which is 1 or 2. n1 represents the speed of the main servo pump set motor, and n2 represents the speed of the slave servo pump set motor.

[0110] Specifically, Figure 9 The inspection process ensures that the oil supply capacity of the standby pump set is under monitoring, and timely switching and alarms are triggered in case of failure.

[0111] Combination Figure 10 The specific process for checking whether the EH system has an oil leak is as follows:

[0112] Collect the current EH oil header flow rate Q0. When ΔQ0 / Q0 < 20%, the EH system is considered normal; when ΔQ0 / Q0 ≥ 20%, determine the change amplitude S of the DEH system valve control command. 调 If the percentage is greater than or equal to 10%, the EH system is considered normal. If not, if ΔP0 / P0 < 10%, the EH system is considered normal. If ΔP0 / P0 ≥ 10%, check if ΔL / L < 10% occurs within 10 minutes. If yes, the EH system is considered normal. If no, the intelligent front end will alarm the DEH or DCS system and activate the big data analysis platform to determine if the EH system has an oil leak. If yes, prompt for action; if no, clear the alarm signal. Here, P0 is the current EH oil header pressure, ΔP0 is the difference between the current EH oil header pressure and the initial EH oil header pressure, and ΔQ0 is the difference between the current EH oil header flow rate and the initial EH oil header flow rate.

[0113] Specifically, under stable system operation, minor oil seepage or leakage will not affect the pump unit's operation. However, if moderate or severe oil leakage occurs, and the pump unit increases its power or even operates in a cascading manner to maintain system pressure, the oil tank will be rapidly emptied. In severe cases, this can cause air to be drawn in, damaging the pump unit and leading to not only a shutdown but also further damage. Therefore, moderate and severe oil leakage in the system must be diagnosed promptly.

[0114] Whenever a surge in traffic occurs, the operating conditions need to be recalculated, and the judgment criteria are as follows:

[0115] If the unit is still in the tripped state, the adjustment command does not fluctuate significantly, the flow rate suddenly increases, and the pressure shows a downward trend. If the liquid level also shows a downward trend, an alarm will be sent to the intelligent front end.

[0116] The process requires first determining the flow rate change. If ΔQ0 / Q0≥20%, the analysis will be initiated; otherwise, it will not be initiated.

[0117] Then determine whether the adjustment command swing is normal. If there is an S... 调 If the percentage is less than 10%, proceed to the next step of the analysis; otherwise, the test results are normal.

[0118] Next, determine whether the pressure change is normal. If ΔP0 / P0≥10%, proceed to the next step of the analysis process; otherwise, the test is considered normal.

[0119] Finally, determine if the flow fluctuation exceeds the limit. If ΔL / L ≥ 10% within 10 minutes, an alarm is triggered to the DCS system, prompting manual intervention for analysis. If a big data analysis platform is available, analysis is initiated simultaneously; otherwise, the system displays normal operation after 10 minutes. Simultaneously, manually check for oil leaks. If no leaks are found, manually clear the alarm information and record it. If leaks are found, address the issue and manually clear the alarm information. See the attached flowchart for the detailed operation process. Figure 10 As shown, Figure 10 The inspection process ensures that oil leaks in the EH system can be detected in a timely manner, and that pump units and alarms can be switched and activated promptly in case of a fault, thus preventing more serious system failures.

[0120] While the invention has been described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the invention. Therefore, it should be understood that many modifications can be made to the exemplary embodiments, and other arrangements can be designed without departing from the spirit and scope of the invention as defined by the appended claims. It should be understood that different dependent claims and features described herein can be combined in ways different from those described in the original claims. It is also understood that features described in conjunction with individual embodiments can be used in other described embodiments.

Claims

1. A method for fault monitoring of a steam turbine EH system, characterized in that, The method includes the following: Step 1: Connect three pipelines in parallel between the EH oil tank and the EH oil header. Install the main servo pump set, the slave servo pump set, and the standby pump set on the three pipelines respectively. Install one flow sensor and one pressure sensor on each of the three pipelines and the EH oil header. Install one current sensor and one speed sensor on each of the main servo pump set, the slave servo pump set, and the standby pump set. Install a liquid level sensor on the EH oil tank. Step 2: When any of the main servo pump group, slave servo pump group, and standby pump group is running, the intelligent front end detects whether the running pump group has a fault based on the output data of the flow sensor, pressure sensor, current sensor, and speed sensor on the pipeline where the running pump group is located. The intelligent front end detects whether the pump interlock pressure switch is malfunctioning based on the pressure sensor output data on the EH oil header; the intelligent front end also detects whether the EH system is leaking oil based on the pressure sensor and flow sensor output data on the EH oil header. The intelligent front end detects the volumetric capacity of the corresponding main servo pump group or slave servo pump group based on the flow sensor on the EH oil header, as well as the rated displacement and motor speed of the main servo pump group or slave servo pump group. Step 2 also includes: the intelligent front end determines whether the slave servo pump group is in operation when the main servo pump group is working, and whether the main servo pump group is in operation when the slave servo pump group is working, based on the pressure data on the EH oil header and the current data output by the main servo pump group or the slave servo pump group. When the main servo pump group and the slave servo pump group are running in parallel, it determines whether to disconnect the slave servo pump group based on the pressure data on the EH oil header and the current data of the running main servo pump group or the slave servo pump group. The process of determining whether the slave servo pump group is in operation when the main servo pump group is working, and whether the main servo pump group is in operation when the slave servo pump group is working: When either the main servo pump group or the slave servo pump group is running, the intelligent front end receives the EH oil header pressure P0 and the running pump group current i. k Simultaneously satisfying P0 < P 0初 ×0.975 and i k ≥0.95×i max When or satisfying i k <0.95×i max and P0 < P 0初 At the same time, the main servo pump group and other pump groups in the slave servo pump group are started, realizing the parallel operation of the main servo pump group and the slave servo pump group, where P 0初 i represents the initial pressure value of the EH oil header. max Rated current of the main servo pump set and the slave servo pump set; The process of determining whether to disconnect from the servo pump unit: After the main servo pump group and the slave servo pump group have been running in parallel for at least 10 minutes, the intelligent front end detects whether P0 > P20 simultaneously. 0初 ×0.975, 0.8×i max >i1+i2 and S 调 <5%, if so, the intelligent front-end control reduces the servo pump group speed n2 to 0 within 10s and disconnects the servo pump group; if not, the main servo pump group and the servo pump group maintain parallel operation, where i1 is the main servo pump group current, i2 is the servo pump group current, and S 调 This refers to the changes in valve control commands for the DEH system.

2. The method for fault monitoring of a steam turbine EH system according to claim 1, characterized in that, In step 2, the pump interlock pressure is checked for malfunctions. The specific process is as follows: The pump interlock pressure switch's operating value is monitored via a transmitter. When P... 0初 ×0.85≥Action Value≥P 0初 When ×0.75, where P 0初 If the initial pressure value of the EH oil header is used, the pump interlock pressure switch is determined to be normal; otherwise, the pump interlock pressure switch is determined to be faulty.

3. The method for fault monitoring of a steam turbine EH system according to claim 1, characterized in that, In step 2, the process of checking whether there is a fault in the main servo pump group or the slave servo pump group in the operating pump group is as follows: The intelligent front end obtains the performance F1 of the main servo pump group or the slave servo pump group based on the motor speed, outlet pressure and motor current received in real time when the main servo pump group or the slave servo pump group is working. When the performance F1 of the main servo pump group or the slave servo pump group is set to the initial performance The intelligent front end outputs the first type of alarm signal to the DEH or DCS system, prompting the replacement of the main servo pump group or the slave servo pump group; When 50% < the performance F1 of the main servo pump group or the slave servo pump group / the set initial performance The intelligent front end outputs a second alarm signal to the DEH or DCS system, and starts the big data analysis platform to determine whether the main servo pump group or the slave servo pump group is faulty. If so, it prompts that the main servo pump group or the slave servo pump group should be replaced. If not, it clears the alarm information. When the performance F1 of the main servo pump group or the slave servo pump group is set to the initial performance The main servo pump group or the slave servo pump group is determined to be normal.

4. The method for fault monitoring of a steam turbine EH system according to claim 1, characterized in that, In step 2, the volumetric capacity of the main servo pump group or the slave servo pump group is detected. The specific process is as follows: When the main servo pump group or the slave servo pump group is working, the intelligent front end determines the EH oil header flow rate Q0 and the rated displacement V of the main servo pump group or the slave servo pump group based on the received EH oil header flow rate Q0 and the rated displacement V of the main servo pump group or the slave servo pump group. g The motor speed n of the main servo pump group or the slave servo pump group i Where i is 1 or 2, n1 represents the speed of the main servo pump group motor, and n2 represents the speed of the slave servo pump group motor. This determines whether to replace the main or slave servo pump group; when 0.7 ≤ Q0 / (n i ×V g When Q0 < 0.9, the intelligent front-end will display an abnormal volumetric capacity of either the main servo pump group or the slave servo pump group; when Q0 / (n) is satisfied... i ×V g When Q0 / (n) < 0.7, the intelligent front-end sends an alarm to the DEH or DCS system, prompting the replacement of the main servo pump group or the slave servo pump group; when Q0 / (n) is satisfied... i ×V g When the value is ≥0.9, the volumetric capacity of the main servo pump group or the slave servo pump group is considered to be normal.

5. The method for fault monitoring of a steam turbine EH system according to claim 1, characterized in that, In step 2, the standby pump unit in the operating pump set is checked for malfunctions. The specific process is as follows: Collect the EH oil header flow rate Q0, and the rated displacement V of any one of the main servo pump group and slave servo pump group. g The motor speed n of either the main servo pump group or the slave servo pump group. i Calculate the performance index F3 of the standby pump set based on the EH oil main pipe pressure P0 and the EH standby pump motor current i3. The intelligent front-end outputs the first alarm signal to the DEH or DCS system, activates the big data analysis platform to determine if the standby pump unit is faulty. If so, the standby pump unit is replaced; otherwise, the alarm information is cleared. The intelligent front-end outputs a second alarm signal to the DEH or DCS system, prompting the replacement of the standby pump set; when The standby pump set was determined to be normal. The initial values ​​of the performance indicators of the standby pump set are i, which is 1 or 2. n1 represents the speed of the main servo pump set motor, and n2 represents the speed of the slave servo pump set motor.

6. The method for fault monitoring of a steam turbine EH system according to claim 5, characterized in that, The performance index F3 of the standby pump set is expressed as: F3=(Q0-n i ×V g )×P0 / i3。 7. The method for fault monitoring of a steam turbine EH system according to claim 1, characterized in that, The specific procedure for checking whether the EH system has an oil leak is as follows: Step C1: Collect the current EH oil header flow rate Q0. When ΔQ0 / Q0 < 20%, the EH system is considered normal; when ΔQ0 / Q0 ≥ 20%, proceed to step C2. Step C2: Determine the change range S of the control valve command in the DEH system. 调 Is it greater than or equal to 10%? If yes, the EH system is considered normal. If not, proceed to step C3. Step C3: Determine whether ΔP0 / P0 < 10%. If yes, determine that the EH system is normal. If no, proceed to step C4. Step C4: Check if ΔL / L < 10% occurs within 10 minutes. If so, the EH system is considered normal. If not, proceed to step C5. Step C5: The intelligent front end sends an alarm to the DEH or DCS system, and the big data analysis platform is activated to determine whether an oil leak has occurred in the EH system. If so, prompt for handling; if not, clear the alarm signal. Here, P0 is the current EH oil header pressure, ΔP0 is the difference between the current EH oil header pressure and the initial EH oil header pressure, and ΔQ0 is the difference between the current EH oil header flow rate and the initial EH oil header flow rate.

8. The method for fault monitoring of a steam turbine EH system according to claim 1, characterized in that, Step 2 also includes: periodically controlling the operation of the standby pump set to check for any malfunctions in the standby pump set.

9. A method for fault monitoring of a steam turbine EH system according to claim 8, characterized in that, The specific process for controlling the operation of the standby pump set is as follows: When the main servo pump set is running and meets the requirements i2=0, i3=0, S 调 When <5% and ΔL / L <5%, start the standby pump group. After the motor current i1 of the main servo pump group and the motor current i3 of the standby pump group are both stable, detect the speed n1 of the main servo pump group, calculate the deceleration rate that will reduce the speed to 0 within 5 minutes, and continuously adjust and reduce n1 according to the deceleration rate until n1 is zero. After n1 decreases to 0 and is maintained at that level for 1 minute, the main servo pump unit is restarted until the speed n1 stabilizes and Q0 < V. g ×n max ×0.8、S 调 When the percentage is <10% and ΔL / L <10%, the standby pump unit is disconnected, where i2 is the motor current of the servo pump unit, and S 调 For changes in the DEH system control valve command, L is the current EH tank level, ΔL is the difference between the current and initial EH tank levels, Q0 is the EH oil header flow rate, and V... g The rated displacement of the master servo pump set and the slave servo pump set, n max The maximum speed of the master servo pump set and the slave servo pump set.

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