A vibration sensor fault identification method for health monitoring of nuclear power emergency diesel
By setting different parameter thresholds for the start-up and shutdown states of the nuclear power emergency diesel engine, and combining multi-parameter fusion judgment, the vibration sensor fault of the nuclear power emergency diesel engine can be identified. This solves the problem of sensor susceptibility to damage in the existing technology and improves the accuracy of fault identification and the comprehensiveness of monitoring.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CNNC FUJIAN FUQING NUCLEAR POWER
- Filing Date
- 2023-11-15
- Publication Date
- 2026-06-09
AI Technical Summary
Existing nuclear power emergency diesel engine vibration sensors are susceptible to malfunctions due to bumps, drops, improper range selection, and improper maintenance during inspection and maintenance, resulting in abnormal monitoring signals. There is a lack of effective fault identification methods.
A multi-parameter fusion judgment method is adopted. Based on the vibration signal characteristics of the nuclear power emergency diesel engine in the start-up and shutdown states, different parameter thresholds are set. By calculating the characteristics of vibration signal peak value, effective value, peak-to-peak value and waveform DC, sensor faults are identified.
It improves the accuracy of sensor fault identification, ensures the comprehensiveness and effectiveness of monitoring, prevents sensor abnormalities from being discovered only after the equipment is turned on, and ensures the accuracy and reliability of monitoring.
Smart Images
Figure CN117538065B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of equipment fault monitoring technology, and specifically relates to a method for identifying vibration sensor faults in the health monitoring of nuclear power emergency diesel engines. Background Technology
[0002] Emergency diesel engines serve as the emergency power source for nuclear power plants, ensuring the safe shutdown of the nuclear reactor and the normal removal of residual heat from the reactor core during accident operations. They are the last line of defense for nuclear safety in power plants. With the rapid development of digitalization and intelligentization in nuclear power plants, emergency diesel engine health monitoring technologies and systems are being gradually promoted and applied.
[0003] Vibration monitoring is one of the main methods for health monitoring of emergency diesel engines. The online vibration monitoring systems for emergency diesel engines, which are gradually being promoted and applied in China, typically require more than ten vibration sensors to be installed on the engine block to monitor the vibration status of various key components. Although modern high-performance vibration sensors are of good quality and generally do not easily fail, in actual field operations, factors such as bumps and knocks during maintenance, drops and impacts, inappropriate range selection, improper maintenance, and wiring errors often lead to sensor malfunctions and abnormal monitoring signals.
[0004] Therefore, in order to address the above problems, there is an urgent need to develop a method for vibration sensor fault identification in nuclear power emergency diesel engines. Summary of the Invention
[0005] The purpose of this invention is to provide a method for identifying vibration sensor faults in the health monitoring of nuclear power emergency diesel engines. This method helps to improve signal quality and provides technical support for the data acquisition quality detection of the nuclear power emergency diesel engine health monitoring system.
[0006] Technical solution to achieve the purpose of this invention:
[0007] A method for vibration sensor fault identification in nuclear power emergency diesel engine health monitoring, the method comprising:
[0008] Step (1): Determine the status of the nuclear power emergency diesel engine based on the key phase signal and the vibration signals from multiple vibration sensors;
[0009] Step (2): With the nuclear power emergency diesel engine running, perform sensor anomaly diagnosis;
[0010] Step (3): When the nuclear power emergency diesel engine is in a shutdown state, perform sensor anomaly diagnosis.
[0011] Step (1) includes:
[0012] Step (1.1): Determine whether the key phase triggering is normal based on the key phase sensor signal;
[0013] Step (1.2): When the key phase trigger is normal, the crankshaft speed signal is obtained and the crankshaft speed is calculated. If the speed is >0, the equipment is in the running state and the sensor abnormality diagnosis sub-process in the power-on state is started; if the speed is <0, the equipment is in the shutdown state and the sensor abnormality diagnosis sub-process in the shutdown state is started.
[0014] Step (1.3): When the key phase triggers abnormally, calculate the peak value and effective value of each vibration sensor signal. If the peak value and effective value of each vibration sensor signal meet the set threshold in the power-on state, the equipment is in the running state, and the sensor abnormality diagnosis sub-process in the power-on state is started; otherwise, if the peak value and effective value of each vibration sensor signal do not meet the set threshold in the power-on state, the equipment is in the shutdown state, and the sensor abnormality diagnosis sub-process in the shutdown state is started.
[0015] In step (1.3), the threshold for the peak and effective values of the vibration sensor signal when the device is powered on is set as follows: vibration peak value > 30 m / s 2 The effective value of vibration is >20 m / s 2 .
[0016] Step (2) includes:
[0017] Step (2.1): Calculate the peak value and effective value of the vibration signal, and determine whether the peak value and effective value of the vibration signal both meet the set threshold under the power-on state;
[0018] Step (2.2): If the peak value and effective value of the vibration signal do not meet the set threshold under the power-on state, faults such as incorrect sensor installation, sensor base falling off, or sensor wiring becoming loose may occur.
[0019] Step (2.3): If the peak value and effective value of the vibration signal meet the set threshold in the power-on state, determine whether the peak value is greater than the range, and determine whether the sensor is abnormal based on whether the peak value is greater than the range.
[0020] Step (2.3) specifically involves:
[0021] If the peak value is greater than the range, the sensor is determined to be out of range;
[0022] If the peak value is not greater than the range, calculate the DC value of the vibration waveform. If the peak value of the DC value exceeds the set threshold, it is determined that the sensor has been subjected to a transient strong impact that exceeds the range or that the components are temporarily overloaded or damaged. If the peak value of the DC value does not exceed the set threshold, it is determined that the sensor is normal.
[0023] In step (2.3), the threshold value for the peak DC flow rate is set to 15 m / s. 2 .
[0024] Step (3) includes:
[0025] Step (3.1): Calculate the peak value and effective value of the vibration signal, and determine whether the peak value and effective value of the vibration signal both meet the set threshold in the power-off state;
[0026] Step (3.2): If the peak value and effective value of the vibration signal do not meet the set threshold in the power-off state, the sensor is subjected to strong interference.
[0027] Step (3.3): If the peak value and effective value of the vibration signal meet the set threshold in the power-off state, determine the peak value of the vibration, and determine whether the sensor is abnormal based on the peak value of the vibration.
[0028] Step (3.3) is as follows: when the peak value of vibration is greater than the set threshold, the sensor is normal; when the peak value of vibration is less than the set threshold, faults such as incorrect sensor installation, sensor base falling off, or sensor wiring loosening may occur.
[0029] The threshold value for the peak vibration rate in step (3.3) is set to 3 m / s. 2 .
[0030] The beneficial technical effects of this invention are as follows:
[0031] 1. This invention addresses the working mode of nuclear power emergency diesel engines as emergency power sources, namely, long-term hot standby shutdown and periodic start-up tests to test the health status of the unit. Based on the multi-source impact characteristics of vibration in key parts of the diesel engine and existing research results on sensor fault identification, a vibration sensor fault identification method is established.
[0032] 2. This invention performs sensor anomaly diagnosis in both the start-up and shutdown states of the nuclear power emergency diesel engine. In addition to the traditional method of judging anomalies only when the equipment is running, it can also judge when the equipment is shut down and in hot standby, preventing sensor anomalies from being discovered only after emergency startup, thus ensuring the comprehensiveness and effectiveness of monitoring.
[0033] 3. This invention fully considers the significant differences in signals between the start-up and shutdown states of nuclear power emergency diesel engines, and addresses the issue that a single judgment logic can easily lead to misjudgments. By pre-judging the equipment's operating status, vibration sensor fault identification is divided into two different judgment logics. Setting parameter thresholds based on the characteristics of different equipment status signals is more reasonable and effective, thus improving the accuracy of fault identification.
[0034] 4. This invention extracts multiple features such as peak value, effective value, peak-to-peak value and waveform direct current of vibration signal, and combines them with the sensor's own measurement range to perform multi-parameter fusion judgment, which effectively improves the accuracy of sensor fault identification. Attached Figure Description
[0035] Figure 1This is a flowchart of an automatic start / stop judgment process for nuclear power emergency diesel engines provided in an embodiment of the present invention;
[0036] Figure 2 This is a flowchart of a vibration monitoring sensor fault identification method for a nuclear power emergency diesel engine in the start-up state, provided by an embodiment of the present invention.
[0037] Figure 3 This is a flowchart illustrating a vibration monitoring sensor fault identification process for a nuclear power emergency diesel engine during shutdown, provided by an embodiment of the present invention.
[0038] Figure 4 This is a schematic diagram of the signal waveform of a vibration monitoring sensor under normal conditions when the nuclear power emergency diesel engine is running, provided in an embodiment of the present invention.
[0039] Figure 5 This is a schematic diagram of the signal waveform of a vibration monitoring sensor under abnormal conditions when a nuclear power emergency diesel engine is running, provided in an embodiment of the present invention.
[0040] Figure 6 This is a schematic diagram of the signal waveform of a vibration monitoring sensor under normal conditions when the nuclear power emergency diesel engine is shut down, as provided in an embodiment of the present invention. Detailed Implementation
[0041] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.
[0042] The diesel engine start-stop status is determined by acquiring the key phase sensor signal. The key phase sensor is usually installed on the side of the flywheel of the diesel engine output shaft, and a key phase block is attached to the edge of the flywheel. When it passes through the key phase sensor, it will generate a voltage pulse signal. The real-time speed of the diesel engine can be obtained by processing the pulse signal.
[0043] When the key phase sensor cannot be installed due to limited conditions, or the pulse trigger fails due to a problem with the key phase sensor itself, once the key phase sensor or its signal becomes abnormal, it is impossible to continue to make judgments based on the key phase sensor signal. Therefore, it is necessary to divide the start-up and shutdown status judgment into two situations: normal key phase signal and abnormal key phase signal.
[0044] When the key phase signal is abnormal, a multi-sensor fusion method is used to determine the start-up and shutdown of the equipment, taking into account the characteristics of multi-vibration measurement point monitoring of diesel engines.
[0045] The fusion method employed in this invention is based on the fundamental assumption that no more than half of the vibration sensors installed on the equipment will fail simultaneously. In fact, this assumption is generally met in practical applications. Since the vibration signal in the shutdown state is essentially background noise or interference noise from hot standby auxiliary equipment, the vibration value is very low. Based on actual field monitoring data, the peak vibration speed in the shutdown state is around 10 m / s. 2 Within this range, the maximum generally will not exceed 15 m / s. 2 To avoid occasional exceedances of the above peak values due to localized noise interference, further judgment was made by referring to the effective vibration value. Actual monitoring signals from the site indicate that the effective vibration value is 7 m / s² when the machine is stopped. 2 Within this range, the maximum speed will not exceed 11 m / s. 2 When powered on, the peak and effective values of the vibration sensor increase with increasing rotational speed and load. Under minimum load conditions, the peak vibration speed is not lower than 50 m / s. 2 The effective value of vibration is not less than 35 m / s. 2 Therefore, the threshold for judging the peak vibration is set at 30 m / s. 2 The threshold for judging the effective value of vibration is 20 m / s. 2 The start-up and shutdown status of the unit can be determined based on the peak and effective values of multiple sensors. It is worth mentioning that the threshold values used in this article are all empirical values from field tests. Different actual engineering sites can be appropriately adjusted according to the test conditions.
[0046] (1) When the unit is in the start-up state
[0047] First, determine whether the peak value and effective value of the vibration signal are both above the reasonable values under the power-on state. If the calculated values are less than the set threshold, it can be inferred that faults such as improper sensor installation, sensor base detachment, or loose sensor wiring have occurred.
[0048] If both the peak vibration value and the effective value exceed the set threshold, further assessment is needed to determine if an over-range issue has occurred. Based on actual field monitoring experience, even if the sensor is not over-range, long-term continuous exposure to strong impacts such as detonation on critical components like the diesel engine cylinder head may cause signal DC displacement due to localized transient strong impacts. Therefore, further calculation of the vibration waveform DC is required. Analysis of actual monitoring data indicates that the peak DC value generally does not exceed 10 m / s. 2 Based on experience, the threshold can be set to 15 m / s. 2 It is worth noting that the peak threshold for direct flow can be adjusted according to different monitoring conditions.
[0049] (2) When the unit is in a shutdown state
[0050] Nuclear power emergency diesel engines are in a hot standby state for a long time. In order to ensure that the sensors are in normal condition after the equipment is turned on, it is still necessary to determine whether the sensors are faulty when the equipment is stopped.
[0051] In the shutdown state, since the vibration mainly consists of background noise or noise transmitted from nearby auxiliary equipment, the main identifiable fault modes are improper installation, strong interference, or damage to internal components that could lead to no signal. If the vibration peak and RMS values exceed the set threshold in the shutdown state, it indicates that the sensor is experiencing strong interference; meanwhile, a normal sensor vibration waveform is generally greater than 5 m / s. 2 If the sensor signal is too small (e.g., less than 3m / s) 2 If the sensor is not installed correctly, the sensor wiring is loose, or the internal components are damaged, the fault may be due to incorrect installation of the sensor, loose sensor wiring, or damage to internal components.
[0052] Specifically, the present invention provides a method for identifying vibration sensor faults in the health monitoring of nuclear power emergency diesel engines, which includes the following steps:
[0053] Step (1): Determine the status of the nuclear power emergency diesel engine, i.e., the start-up and shutdown status of the nuclear power emergency diesel engine, based on the key phase signal and the vibration signals from multiple vibration sensors.
[0054] like Figure 1 As shown, the automatic start / stop judgment process for nuclear power emergency diesel engines specifically includes:
[0055] Step (1.1): Determine if the key phase trigger is normal.
[0056] Step (1.2): When the key phase trigger is normal, the crankshaft speed signal is obtained and the crankshaft speed is calculated. If the speed is >0, the equipment is in the running state and the sensor abnormality diagnosis sub-process in the power-on state is started; if the speed is <0, the equipment is in the shutdown state and the sensor abnormality diagnosis sub-process in the shutdown state is started.
[0057] Step (1.3): When the key phase triggering is abnormal, calculate the peak value and RMS value of each vibration sensor signal. If the vibration peak value is >30m / s 2 And the effective value of vibration is >20m / s 2 If the device is running, the sensor anomaly diagnosis subprocess in the power-on state will be started; otherwise, the device is in a shutdown state, and the sensor anomaly diagnosis subprocess in the shutdown state will be started.
[0058] Step (2): With the nuclear power emergency diesel engine running, perform sensor anomaly diagnosis.
[0059] like Figure 2 As shown, the specific procedures for identifying faults in vibration monitoring sensors during the startup state of a nuclear power emergency diesel engine include:
[0060] Step (2.1): Calculate the peak value and effective value of the vibration signal.
[0061] When the vibration signal peak value is not greater than 30m / s 2 And the effective value of vibration is >20m / s 2 If this happens, faults such as incorrect sensor installation, sensor base detachment, or loose sensor wiring may occur.
[0062] Step (2.2) satisfies the vibration signal peak value > 30m / s 2 And the effective value of vibration is >20m / s 2 At that time, determine whether the peak value is greater than the range.
[0063] Step (2.3) does not meet the requirement that the peak value of the vibration signal is >30m / s 2 And the effective value of vibration is >20m / s 2 At that time, calculate the DC quantity of the vibration waveform.
[0064] When the peak DC flow rate exceeds 15 m / s 2 If the sensor is subjected to a transient strong impact that exceeds its range, or if the components are temporarily overloaded or damaged, the sensor is normal.
[0065] Step (3): When the nuclear power emergency diesel engine is in a shutdown state, perform sensor anomaly diagnosis.
[0066] like Figure 3 As shown, the specific procedures for fault identification of vibration monitoring sensors during nuclear power plant emergency diesel engine shutdown include:
[0067] Step (3.1): Calculate the peak value and effective value of the vibration signal.
[0068] Step (3.2): When the vibration signal peak value is not <30m / s 2 And the effective vibration value is <20m / s 2 At that time, the sensor is subject to strong interference.
[0069] Step (3.3) satisfies the vibration signal peak value <30m / s 2 And the effective vibration value is <20m / s 2 At that time, determine the peak value of the vibration.
[0070] When the peak-to-peak value of vibration is >3m / s 2 If the sensor is working properly, it is normal; otherwise, there may be faults such as the sensor not being installed correctly, the sensor base falling off, or the sensor wiring becoming loose.
[0071] Taking the following example, using the fault identification method for vibration monitoring sensors of a nuclear power emergency diesel engine according to the present application to determine the actual vibration monitoring status of a model MTU956V20 nuclear power emergency diesel engine, the present invention provides a method for fault identification of vibration sensors for health monitoring of nuclear power emergency diesel engines, including the following steps:
[0072] Step (1): Obtain the key phase sensor signal of the diesel engine to determine the start-stop status of the diesel engine. The key phase sensor is usually installed on the side of the flywheel of the diesel engine output shaft, and the key phase block is pasted on the edge of the flywheel. When it passes through the key phase sensor, it will generate a voltage pulse signal. The real-time speed of the diesel engine can be obtained by processing the pulse signal.
[0073] Step (2): When the unit is in the power-on state, first determine whether the peak value and effective value of the vibration signal are both above the reasonable value in the power-on state. If the calculated value is less than the set threshold, it can be inferred that the sensor is not installed properly, the sensor base is detached, or the sensor wiring is loose.
[0074] If both the peak vibration value and the effective value exceed the set threshold, further assessment is needed to determine if an over-range issue has occurred. Based on actual field monitoring experience, even if the sensor is not over-range, long-term continuous exposure to strong impacts such as detonation on critical components like the diesel engine cylinder head may cause signal DC displacement due to localized transient strong impacts. Therefore, further calculation of the vibration waveform DC is required. Analysis of actual monitoring data indicates that the peak DC value generally does not exceed 10 m / s. 2 Based on experience, the threshold can be set to 15 m / s. 2 It is worth noting that the peak threshold for direct flow can be adjusted according to different monitoring conditions.
[0075] The sensor's signal waveform under normal operating conditions and when powered on is as follows: Figure 4 As shown, the peak value reaches 800 mm / s 2 The unit experiences significant vibration and impact during full-load operation, and the sensors frequently exhibit issues such as… Figure 5 The abnormal vibration waveforms shown both cause the peak value of the DC component waveform to greatly exceed the alarm threshold.
[0076] Step (3): When the unit is in a shutdown state, if the vibration peak value and effective value exceed the set threshold, it indicates that the sensor is under strong interference; at the same time, the vibration waveform of a normal sensor is generally greater than 5m / s. 2 If the sensor signal is too small (e.g., less than 3m / s) 2 If the sensor is not installed correctly, the sensor wiring is loose, or the internal components are damaged, the fault may be due to incorrect installation of the sensor, loose sensor wiring, or damage to internal components.
[0077] The sensor signal waveform under normal conditions is as follows: (Symptoms) Figure 6As shown, the vibration peaks are all around 10 m / s². 2 Within.
[0078] The present invention has been described in detail above with reference to the accompanying drawings and embodiments. However, the present invention is not limited to the above embodiments, and various changes can be made within the scope of knowledge possessed by those skilled in the art without departing from the spirit of the present invention. All contents not described in detail in the present invention can be derived from existing technologies.
Claims
1. A method for identifying vibration sensor faults in the health monitoring of nuclear power emergency diesel engines, characterized in that, The method includes: Step (1): Determine the status of the nuclear power emergency diesel engine based on the key phase signal and the vibration signals from multiple vibration sensors; Step (2): With the nuclear power emergency diesel engine running, perform sensor anomaly diagnosis; Step (3): While the nuclear power emergency diesel engine is in a shutdown state, perform sensor anomaly diagnosis; Step (1) includes: Step (1.1): Determine whether the key phase triggering is normal based on the key phase sensor signal; Step (1.2): When the key phase trigger is normal, the crankshaft speed signal is obtained and the crankshaft speed is calculated. If the speed is >0, the equipment is in the running state and the sensor abnormality diagnosis sub-process in the power-on state is started; if the speed is <0, the equipment is in the shutdown state and the sensor abnormality diagnosis sub-process in the shutdown state is started. Step (1.3): When the key phase trigger is abnormal, calculate the peak value and effective value of each vibration sensor signal. If the peak value and effective value of each vibration sensor signal meet the set threshold in the power-on state, the equipment is in the running state and the sensor abnormality diagnosis sub-process in the power-on state is started; otherwise, if the peak value and effective value of each vibration sensor signal do not meet the set threshold in the power-on state, the equipment is in the shutdown state and the sensor abnormality diagnosis sub-process in the shutdown state is started. Step (2) includes: Step (2.1): Calculate the peak value and effective value of the vibration signal, and determine whether the peak value and effective value of the vibration signal both meet the set threshold under the power-on state; Step (2.2): If the peak value and effective value of the vibration signal do not meet the set threshold under the power-on state, the sensor may not be installed correctly, the sensor base may fall off, or the sensor wiring may be loose. Step (2.3): If the peak value and effective value of the vibration signal meet the set threshold under the power-on state, determine whether the peak value is greater than the range, and determine whether the sensor is abnormal based on whether the peak value is greater than the range. Step (3) includes: Step (3.1): Calculate the peak value and effective value of the vibration signal, and determine whether the peak value and effective value of the vibration signal both meet the set threshold in the power-off state; Step (3.2): If the peak value and effective value of the vibration signal do not meet the set threshold in the power-off state, the sensor is subjected to strong interference. Step (3.3): If the peak value and effective value of the vibration signal meet the set threshold in the power-off state, determine the peak value of the vibration, and determine whether the sensor is abnormal based on the peak value of the vibration.
2. The method for vibration sensor fault identification in nuclear power emergency diesel engine health monitoring according to claim 1, characterized in that, In step (1.3), the threshold for the peak and effective values of the vibration sensor signal when the device is powered on is set as follows: vibration peak value > 30 m / s 2 The effective value of vibration is >20 m / s 2 .
3. The method for vibration sensor fault identification in nuclear power emergency diesel engine health monitoring according to claim 1, characterized in that, The specific steps (2.3) are as follows: If the peak value is greater than the range, the sensor is determined to be out of range; If the peak value is not greater than the range, calculate the DC value of the vibration waveform. If the peak value of the DC value exceeds the set threshold, it is determined that the sensor has been subjected to a transient strong impact that exceeds the range or that the components are temporarily overloaded or damaged. If the peak value of the DC value does not exceed the set threshold, it is determined that the sensor is normal.
4. The method for vibration sensor fault identification in nuclear power emergency diesel engine health monitoring according to claim 3, characterized in that, In step (2.3), the threshold value for the peak direct current is set to 15 m / s. 2 .
5. The method for vibration sensor fault identification in nuclear power emergency diesel engine health monitoring according to claim 1, characterized in that, The specific steps (3.3) are as follows: when the peak value of vibration is greater than the set threshold, the sensor is normal; when the peak value of vibration is less than the set threshold, there may be faults such as the sensor not being installed correctly, the sensor base falling off, or the sensor wiring becoming loose.
6. The method for vibration sensor fault identification in nuclear power emergency diesel engine health monitoring according to claim 5, characterized in that, The threshold value for the peak vibration rate in step (3.3) is set to 3 m / s. 2 .