Diagnostic Method of False Signals in Vibration Measurement System of Steam Turbine Generator Set

Abstract

The present invention relates to a method for diagnosing false signals in a vibration measurement system of a steam turbine generator set. The method comprises the following steps: recording the X-direction shaft vibration and its corresponding X-direction phase angle, the Y-direction shaft vibration and its corresponding Y-direction phase angle, and the bearing vibration of each bearing during stable operation and actual operation of the steam turbine generator set; and determining whether the vibration signal is a false signal based on whether the maximum change rate of the X-direction shaft vibration, the maximum change rate of the Y-direction shaft vibration, and the maximum change rate of the bearing vibration meet preset conditions. The present invention is based on the mutual coupling relationship between shaft vibration and bearing vibration, and can effectively identify whether there is a false interference signal in the vibration measurement system of the steam turbine generator set by measuring the change in shaft vibration per unit time and the change in vibration at four measuring points across two positions of the inner rotor, thereby effectively improving the safety and economy of the unit.

Description

Technical Field

[0001] The invention relates to the field of steam turbine generator sets, and in particular to a method for diagnosing false signals in a vibration measurement system of a steam turbine generator set. Background Art

[0002] The vibration measurement system of a steam turbine generator set is a critical safeguard for protecting the safety of the equipment. During normal operation, operators monitor the safety of the equipment using real-time data displayed by the vibration measurement system. When abnormal vibration data is detected, operators make appropriate adjustments or shut down the equipment based on the degree of change, effectively preventing equipment accidents. During vibration fault analysis, professional technicians use specialized analysis software to perform a Fourier transform (FFT) on the data from the vibration measurement system to obtain various spectral data, thereby analyzing and diagnosing the cause of the vibration anomaly. False signals in the measurement system can affect operators' monitoring and operations, as well as the professional technicians' ability to accurately analyze vibration faults. Therefore, it is necessary to diagnose false signals in the vibration measurement system of steam turbine generator sets. Summary of the Invention

[0003] The purpose of the present invention is to provide a method for diagnosing false signals in a vibration measurement system of a steam turbine generator set, which can effectively identify false signals in the vibration measurement system of the steam turbine generator set, thereby providing a guarantee for unit monitoring and analysis.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is:

[0005] A method for diagnosing false signals in a vibration measurement system of a steam turbine generator set comprises the following steps:

[0006] Step 1: Record the X-axis vibration A of each bearing of the steam turbine generator set during stable operation. i 、Y direction axis vibration B i And Wa Zhen W i , i=1, 2, ..., N respectively represent the numbers corresponding to the bearings;

[0007] Step 2: Record the X-axis axial vibration of each bearing during actual operation of the steam turbine generator set. and its corresponding X-direction phase angle Y-axis vibration and its corresponding Y-direction phase angle And Wa Zhen W i max As a set of vibration signals;

[0008] Step 3: Based on the X-axis vibration of each bearing and its corresponding X-direction phase angle Y-axis vibration and its corresponding Y-direction phase angle And Wa Zhen W i max , respectively calculating the diagnostic parameters of each bearing corresponding to each measuring point;

[0009] Step 4: using the diagnostic parameters corresponding to the measuring points of each bearing to determine whether abnormal vibration occurs, if so, proceed to step 5, otherwise return to step 2;

[0010] Step 5: After a period of time, use the diagnostic parameters of each measuring point corresponding to each bearing to determine whether the abnormal vibration phenomenon of each measuring point recovers on its own. If so, execute step 6; otherwise, execute step 7;

[0011] Step 6: Record the time it takes for the vibration abnormality of each measuring point to recover on its own. If the time it takes for the vibration abnormality to recover on its own is less than a preset time threshold, the vibration signal corresponding to the measuring point is a false signal. Otherwise, execute step 7.

[0012] Step 7: Make a judgment based on the judgment conditions of the diagnostic parameters of each measuring point corresponding to each bearing. If the judgment conditions are met, the vibration signal corresponding to the measuring point is a false signal; otherwise, the vibration signal corresponding to the measuring point is a true signal.

[0013] In step 3, the diagnostic parameters of the bearing corresponding to each measuring point include: the maximum change rate of the shaft vibration in the X direction Maximum change rate of axial vibration in the Y direction And the maximum change rate of the bearing vibration

[0014] In step 4, if the maximum change rate of the X-axis vibration of the measuring point Δη A(i) , the maximum change rate of the Y-axis vibration Δη B(i) , the maximum change rate of the bearing vibration Δη W(i) If any one of the above exceeds the preset change rate threshold, it is determined that abnormal vibration occurs.

[0015] In step 5, if the maximum change rate Δη of the X-axis vibration of the measuring point exceeds the change rate threshold, A(i) , the maximum change rate of the Y-axis vibration Δη B(i) Or the maximum change rate of the tile vibration Δη W(i) If the value recovers to below the change rate threshold, it is determined that the abnormal vibration phenomenon has recovered on its own.

[0016] The change rate threshold is 50%.

[0017] In step 6, the time threshold is 3s.

[0018] In step 7, the judgment conditions include: ① for the i-th bearing and the i+1-th bearing, if the maximum change rate of the X-direction axial vibration corresponding to the i-th bearing is Δη A(i) , the maximum change rate of the Y-axis vibration Δη B(i) and the maximum change rate Δη of the X-direction axial vibration corresponding to the i+1th bearing A(i+1) , the maximum change rate of the Y-axis vibration Δη B(i+1) Only one of them exceeds the preset change rate threshold; ② For the i-th bearing and the i+1-th bearing, if the maximum change rate Δη of the X-direction axial vibration corresponding to the i-th bearing A(i) , the maximum change rate of the Y-axis vibration Δη B(i) and the maximum change rate Δη of the X-direction axial vibration corresponding to the i+1th bearing A(i+1) , the maximum change rate of the Y-axis vibration Δη B(i+1) Only two of them exceed the change rate threshold, and the maximum change rate Δη of the bearing vibration corresponding to the i-th bearing W(i) , the maximum change rate Δη of the bearing vibration corresponding to the i+1th bearing W(i+1) ③ For the i-th bearing and the i+1-th bearing, if the maximum change rate Δη of the X-direction axial vibration corresponding to the i-th bearing A(i) , the maximum change rate of the Y-axis vibration Δη B(i) and the maximum change rate Δη of the X-direction axial vibration corresponding to the i+1th bearing A(i+1) , the maximum change rate of the Y-axis vibration Δη B(i+1) All exceed the change rate threshold, but the X-direction phase angle corresponding to the i-th bearing is Phase angle with Y direction The difference between the two, the X-direction phase angle corresponding to the i+1 bearing Phase angle with Y direction The difference is less than or equal to the preset angle threshold, and the maximum change rate of the bearing vibration corresponding to the i-th bearing is Δη W(i) , the maximum change rate Δη of the bearing vibration corresponding to the i+1th bearing W(i+1) None exceeded the rate of change threshold;

[0019] If any one of the judgment conditions is met, the vibration signal exceeding the change rate threshold is a false signal.

[0020] The angle threshold is 45°.

[0021] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art: the present invention is based on the mutual coupling relationship between shaft vibration and bearing vibration, and can effectively identify whether there is a false interference signal in the vibration measurement system of the steam turbine generator set through the change in shaft vibration per unit time and the change in vibration at four measuring points at two positions across the inner rotor, thereby effectively improving the safety and economy of the unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Attachment Figure 1 The present invention is a flow chart of a method for diagnosing false signals in a vibration measurement system of a steam turbine generator set.

[0023] Attachment Figure 2 This is a schematic diagram of the shaft support of the steam turbine generator set. DETAILED DESCRIPTION

[0024] The present invention will be further described below with reference to the embodiments shown in the accompanying drawings.

[0025] Example 1: As shown in the attached Figure 1 As shown, a method for diagnosing false signals in a vibration measurement system of a steam turbine generator set includes the following steps:

[0026] Step 1: Record the X-axis vibration A of each bearing of the steam turbine generator set during stable operation. i and its corresponding X-direction phase angle θ A-i 、Y direction axis vibration B i and its corresponding Y-direction phase angle θ B-i And Wa Zhen W i , i=1,2,…,N respectively represent the numbers corresponding to each bearing, and each bearing is numbered in sequence according to the distribution order.

[0027] Step 2: Record the X-axis vibration of each bearing during actual operation of the steam turbine generator set. and its corresponding X-direction phase angle Y-axis vibration and its corresponding Y-direction phase angle And Wa Zhen W i max As a set of vibration signals.

[0028] Step 3: Based on the X-axis vibration of each bearing and its corresponding X-direction phase angle Y-axis vibration and its corresponding Y-direction phase angle And Wa Zhen W i max , calculate the diagnostic parameters of each bearing corresponding to each measuring point respectively.

[0029] The diagnostic parameters of the bearing corresponding to each measuring point include: the maximum change rate of the shaft vibration in the X direction Maximum change rate of axial vibration in the Y direction And the maximum change rate of the bearing vibration

[0030] Step 4: Use the diagnostic parameters of each bearing corresponding to each measuring point to determine whether abnormal vibration occurs. If so, proceed to step 5, otherwise return to step 2. If the maximum change rate of the X-axis vibration of the measuring point is Δη A(i) , Maximum change rate of axial vibration in the Y direction Δη B(i) , Maximum change rate of bearing vibration Δη W(i) If any one of the above exceeds the preset change rate threshold, it is determined that abnormal vibration occurs. In this embodiment, the change rate threshold is 50%, so if Δη A(i) >50% or Δη B(i) >50% or Δη W(i) >50%, it is judged that abnormal vibration occurs, that is, abnormal.

[0031] Step 5: After a period of time, use the diagnostic parameters of each bearing corresponding to each measuring point to determine whether the abnormal vibration phenomenon at each measuring point recovers on its own. If so, proceed to step 6; otherwise, proceed to step 7.

[0032] If the maximum change rate of the X-axis vibration of the measuring point exceeds the change rate threshold, Δη A(i) , Maximum change rate of axial vibration in the Y direction Δη B(i) Or the maximum change rate of the vibration Δη W(i) If the vibration abnormality is restored to below the change rate threshold, it is judged that the vibration abnormality has recovered by itself, that is, if after a period of time, the steam turbine generator set recovers from Δη A(i) >50% or Δη B(i) >50% or Δη W(i) >50% recovery to Δη A(i) ≤50% or Δη B(i) ≤50% or Δη W(i) If the value is less than or equal to 50%, it is judged that the abnormal vibration phenomenon at the corresponding measuring point has recovered on its own.

[0033] Step 6: Record the time it takes for the vibration abnormality at each measuring point to recover (vibration abnormality time), including the X-direction vibration recovery time T A(i) , Y direction vibration recovery time T B(i) And the vibration recovery time T W(i) If the time it takes for the vibration abnormality to recover by itself is less than the preset time threshold, the vibration signal corresponding to the measuring point is a false signal, otherwise, execute step 7;

[0034] Step 5 is to record the steam turbine generator set from Δη A(i) >50% or Δη B(i)>50% or Δη W(i) >50% recovery to Δη A(i) ≤50% or Δη B(i) ≤50% or Δη W(i) ≤50% of the time required T A(i) 、T B(i) or T W(i) , the time threshold is 3s, then if T A(i) <3s, T B(i) <3s or T W(i) <3s, the vibration signal corresponding to the measuring point i is a false signal; otherwise, the vibration anomaly is real and it is necessary to further implement step 7 to analyze and diagnose its specific cause.

[0035] It can be seen from this that if the vibration anomaly has not recovered after the time corresponding to the time threshold has passed since the vibration anomaly was discovered, step 7 is executed for further judgment.

[0036] Step 7: Use the judgment conditions based on the diagnostic parameters of each measuring point corresponding to each bearing to make a judgment. If the judgment conditions are met, the vibration signal corresponding to the measuring point is a false signal; otherwise, the vibration signal corresponding to the measuring point is a true signal.

[0037] In step 7, the judgment conditions include: ① For the i-th bearing and the i+1-th bearing (i.e., the two bearings in the span), if the maximum change rate of the X-direction axial vibration corresponding to the i-th bearing is Δη A(i) , Maximum change rate of axial vibration in the Y direction Δη B(i) And the maximum change rate of the X-direction axial vibration corresponding to the i+1 bearing Δη A(i+1) , Maximum change rate of axial vibration in the Y direction Δη B(i+1) Only one of them exceeds the preset change rate threshold; ② For the i-th bearing and the i+1-th bearing (i.e., the two bearings in the span), if the maximum change rate of the X-direction axial vibration corresponding to the i-th bearing is Δη A(i) , Maximum change rate of axial vibration in the Y direction Δη B(i) And the maximum change rate of the X-direction axial vibration corresponding to the i+1 bearing Δη A(i+1) , Maximum change rate of axial vibration in the Y direction Δη B(i+1) Only two of them exceed the change rate threshold, and the maximum change rate of bearing vibration corresponding to the i-th bearing is Δη W(i) , the maximum change rate of bearing vibration corresponding to the i+1th bearing Δη W(i+1) ③ For the i-th bearing and the i+1-th bearing (i.e., the two bearings in the span), if the maximum change rate of the X-direction axial vibration corresponding to the i-th bearing is Δη A(i) , Maximum change rate of axial vibration in the Y direction Δη B(i) And the maximum change rate of the X-direction axial vibration corresponding to the i+1 bearing Δη A(i+1), Maximum change rate of axial vibration in the Y direction Δη B(i+1) All exceed the rate of change threshold, but the X-direction phase angle corresponding to the i-th bearing is Phase angle with Y direction The difference between the two, the X-direction phase angle corresponding to the i+1 bearing Phase angle with Y direction The difference is less than or equal to the preset angle threshold (same direction), and the maximum change rate of bearing vibration corresponding to the i-th bearing is Δη W(i) , the maximum change rate of bearing vibration corresponding to the i+1th bearing Δη W(i+1) Neither exceeds the rate of change threshold. If any of the judgment conditions is met, the vibration signal exceeding the rate of change threshold is a false signal. The angle threshold is 45°.

[0038] In this step, the three conditions mentioned above can be judged in turn. First, determine whether condition ① is met. If so, the vibration signal exceeding the change rate threshold is a false signal. For example, if Δη A(i) >50% and Δη B(i) ≤50% and Δη A(i+1) ≤50% and Δη B(i+1) ≤50%, the vibration signal in the X direction of point i is a false signal. If condition ① is not met, continue to judge whether condition ② is met. If it is met, the vibration signal exceeding the change rate threshold is a false signal. For example, if Δη A(i) >50%, Δη B(i) >50%, Δη A(i+1) ≤50%, Δη B(i+1) ≤50%, and Δη W(i) ≤50%, Δη W(i+1) ≤50%, then the vibration abnormality signal in the X and Y directions of point i is a false signal, otherwise the vibration abnormality is real. If condition ② is not met, continue to judge whether condition ③ is met. If it is met, the vibration signal exceeding the change rate threshold is a false signal, such as Δη A(i) >50%, Δη B(i) >50%, Δη A(i+1) >50%, Δη B(i+1) >50%, and and Δη W(i) ≤50%, Δη W(i+1) If the value is less than or equal to 50%, the abnormal vibrations at the four points of bearing i and bearing i+1 in the same span are false signals.

[0039] A certain unit is a DKY4-4N41B supercritical 600MW single-intermediate reheat, single-shaft, four-cylinder, four-exhaust reaction steam turbine manufactured by Beizhong Alstom (Beijing) Electrical Equipment Co., Ltd. The generator is a 50WT23E-138 three-phase synchronous steam turbine generator manufactured by Beizhong Alstom Electrical Equipment Co., Ltd. The steam turbine unit adopts a modular design, including a reverse single-flow high-pressure module, a split-flow medium-pressure module, and two split-flow low-pressure modules. The shaft support is as follows: Figure 2 shown.

[0040] When the turbine was running at a constant speed of 3000 rpm, the vibration of the bearings was good, all below 50 μm. After grid connection and load, the vibration of the #5 and #6 shafts on the generator side increased with increasing load, and the phase also changed accordingly. When the unit load increased to 600 MW, the vibration amplitude of the #5 and #6 bearings reached 130 μm. The phase of the shaft vibration on both sides was essentially the same, and the bearing vibration did not change much. Specific vibration data are shown in Table 1.

[0041] Table 1 Shaft vibration data of bearings #5 and #6

[0042] Unit: Pass frequency (μm) / Phase (∠°)

[0043]

[0044] #5 and #6 bearings are in the same span, Δη A(5) =350%≥50%, Δη B(5) =537%≥50%, Δη A(6) =218%≥50%, Δη B(6) =370%≥50%, and and Δη W(5) ≤50%, Δη W(6) ≤50%, which meets judgment condition ③, so the measurement signals of the four points are judged to be false signals.

[0045] To verify the accuracy of the diagnosis, the unit maintained 380MW operation and swapped the 6X and 7X shaft vibration probes between their corresponding measurement circuits. The 6X vibration amplitude decreased from 88µm to approximately 21µm, while the 7X vibration amplitude increased from 21µm to 103µm, confirming an anomaly in the 6X vibration measurement circuit. Subsequent inspection of the #5 and #6 bearing shaft vibration measurement circuits revealed similar anomalies in other measurement circuits. After eliminating interfering signals, the vibration status of the #5 and #6 bearings is shown in Table 2.

[0046] Table 2 Shaft vibration data of bearings #5 and #6

[0047] Unit: Pass frequency (μm) / Phase (∠°)

[0048]

[0049] Advantages of this solution: The present invention's method for diagnosing false signals in a steam turbine generator set's vibration measurement system comprehensively considers factors such as bearing shaft vibration, bearing vibration, and time across the inner rotor. Based on the mutual coupling relationship between shaft and bearing vibration, the method effectively identifies the presence of interference signals in the steam turbine generator set's vibration measurement system by measuring the change in shaft vibration per unit time and the change in vibration at four measuring points at two locations across the inner rotor. This method can promptly eliminate false vibration anomalies caused by sensor problems, avoid unnecessary downtime for inspection and processing, narrow the scope of vibration fault detection, and effectively improve the unit's safety and economic efficiency.

[0050] 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 equivalent changes or modifications made in accordance with the spirit of the present invention are intended to be covered by the scope of protection of the present invention.

Claims

1. A method for diagnosing false signals in a vibration measurement system of a steam turbine generator set, characterized by: The method for diagnosing false signals in a vibration measurement system of a steam turbine generator set comprises the following steps: Step 1: Record the X-axis vibration A of each bearing of the steam turbine generator set during stable operation. i 、Y direction axis vibration B i And Wa Zhen W i , i=1, 2, ..., N respectively represent the numbers corresponding to the bearings; Step 2: Record the X-axis axial vibration of each bearing during actual operation of the steam turbine generator set. and its corresponding X-direction phase angle Y-axis vibration and its corresponding Y-direction phase angle And Wa Zhen W i max As a set of vibration signals; Step 3: Based on the X-axis vibration of each bearing and its corresponding X-direction phase angle Y-axis vibration and its corresponding Y-direction phase angle And Wa Zhen W i max , respectively calculating the diagnostic parameters of each bearing corresponding to each measuring point; Step 4: using the diagnostic parameters corresponding to the measuring points of each bearing to determine whether abnormal vibration occurs, if so, proceed to step 5, otherwise return to step 2; Step 5: After a period of time, use the diagnostic parameters of each measuring point corresponding to each bearing to determine whether the abnormal vibration phenomenon of each measuring point recovers on its own. If so, execute step 6; otherwise, execute step 7; Step 6: Record the time it takes for the vibration abnormality of each measuring point to recover on its own. If the time it takes for the vibration abnormality to recover on its own is less than a preset time threshold, the vibration signal corresponding to the measuring point is a false signal. Otherwise, execute step 7. Step 7: Make a judgment based on the judgment conditions of the diagnostic parameters of each measuring point corresponding to each bearing. If the judgment conditions are met, the vibration signal corresponding to the measuring point is a false signal; otherwise, the vibration signal corresponding to the measuring point is a true signal.

2. The method for diagnosing false signals in a vibration measurement system for a steam turbine generator set according to claim 1, characterized in that: In step 3, the diagnostic parameters of the bearing corresponding to each measuring point include: the maximum change rate of the shaft vibration in the X direction Maximum change rate of axial vibration in the Y direction And the maximum change rate of the bearing vibration 3. The method for diagnosing false signals in a vibration measurement system for a steam turbine generator set according to claim 2, characterized in that: In step 4, if the maximum change rate of the X-axis vibration of the measuring point Δη A(i) , the maximum change rate of the Y-axis vibration Δη B(i) , the maximum change rate of the bearing vibration Δη W(i) If any one of the above exceeds the preset change rate threshold, it is determined that abnormal vibration occurs.

4. The method for diagnosing false signals in a vibration measurement system for a steam turbine generator set according to claim 3, wherein: In step 5, if the maximum change rate Δη of the X-axis vibration of the measuring point exceeds the change rate threshold, A(i) , the maximum change rate of the Y-axis vibration Δη B(i) Or the maximum change rate of the tile vibration Δη W(i) If the value recovers to below the change rate threshold, it is determined that the abnormal vibration phenomenon has recovered on its own.

5. The method for diagnosing false signals in a vibration measurement system for a steam turbine generator set according to claim 3 or 4, characterized in that: The change rate threshold is 50%.

6. The method for diagnosing false signals in a vibration measurement system for a steam turbine generator set according to claim 4, characterized in that: In step 6, the time threshold is 3s.

7. The method for diagnosing false signals in a vibration measurement system for a steam turbine generator set according to claim 6, characterized in that: In step 7, the judgment conditions include: ① for the i-th bearing and the i+1-th bearing, if the maximum change rate of the X-direction axial vibration corresponding to the i-th bearing is Δη A(i) , the maximum change rate of the Y-axis vibration Δη B(i) and the maximum change rate Δη of the X-direction axial vibration corresponding to the i+1th bearing A(i+1) , the maximum change rate of the Y-axis vibration Δη B(i+1) Only one of them exceeds the preset change rate threshold; ② For the i-th bearing and the i+1-th bearing, if the maximum change rate Δη of the X-direction axial vibration corresponding to the i-th bearing A(i) , the maximum change rate of the Y-axis vibration Δη B(i) and the maximum change rate Δη of the X-direction axial vibration corresponding to the i+1th bearing A(i+1) , the maximum change rate of the Y-axis vibration Δη B(i+1) Only two of them exceed the change rate threshold, and the maximum change rate Δη of the bearing vibration corresponding to the i-th bearing W(i) , the maximum change rate Δη of the bearing vibration corresponding to the i+1th bearing W(i+1) ③ For the i-th bearing and the i+1-th bearing, if the maximum change rate Δη of the X-direction axial vibration corresponding to the i-th bearing A(i) , the maximum change rate of the Y-axis vibration Δη B(i) and the maximum change rate Δη of the X-direction axial vibration corresponding to the i+1th bearing A(i+1) , the maximum change rate of the Y-axis vibration Δη B(i+1) All exceed the change rate threshold, but the X-direction phase angle corresponding to the i-th bearing is Phase angle with Y direction The difference between the two, the X-direction phase angle corresponding to the i+1 bearing Phase angle with Y direction The difference is less than or equal to the preset angle threshold, and the maximum change rate of the bearing vibration corresponding to the i-th bearing is Δη W(i) , the maximum change rate Δη of the bearing vibration corresponding to the i+1th bearing W(i+1) None exceeded the rate of change threshold; If any one of the judgment conditions is met, the vibration signal exceeding the change rate threshold is a false signal.

8. The method for diagnosing false signals in a vibration measurement system for a steam turbine generator set according to claim 7, characterized in that: The angle threshold is 45°.

Images