Coal power unit valve fault diagnosis and treatment method

Abstract

The invention relates to the field of coal power, in particular to a coal power unit valve fault diagnosis and treatment method. Fault diagnosis and treatment for abnormal vibration and noise of a bearing bush during operation of an existing unit are lacked. The invention provides a coal power unit valve fault diagnosis and treatment method. The method comprises the following steps that the vibration spectrum fv of a steam turbine is measured; analyzing the vibration spectrum fv; the valve noise frequency fc, the bearing bush inherent frequency fb and the spring box inherent frequency ft are tested; calculating the ratio of the vibration spectrum fv to the valve noise frequency fc; comparing the vibration spectrum fv with the inherent frequency ft of the spring box, and turning to the next step when fv is less than or equal to ft; calculating the ratio of the vibration spectrum fv to the inherent frequency fb of the bearing bush, and turning to the next step when fv / fb is greater than or equal to 0.85; if the fault is diagnosed to be high-frequency intermittent excitation force, performing a valve activity test; the perpendicularity of the spring box body is adjusted; and measuring the vibration value of the tile vibration, and ending when the vibration value is less than 3.8 mm / s. The vibration frequency is analyzed and combined with the resonance theory, vibration reasons are judged and treated, and vibration and noise are reduced.

Description

Technical Field

[0001] The invention relates to the field of coal-fired power generation, and in particular to a method for diagnosing and treating valve faults of coal-fired power generation units. Background Art

[0002] As a new energy-saving technology, tangential full-circle steam inlet technology is widely used in steam turbine units. Some ultra-supercritical 1000MW and 660MW steam turbine units adopt horizontal tangential full-circle steam inlet, which has the characteristics of small steam inlet pressure loss, low construction cost, and small volume margin during load rejection, which helps to improve the flexibility and safety and reliability of the unit. Later, staggered horizontal and staggered vertical tangential full-circle steam inlet schemes were developed and applied to ultra-supercritical steam turbine units, further improving the efficiency of the unit. At present, in a large number of 1000MW units, many units will experience abnormal vibration of the bearings during operation, accompanied by abnormal noise, which seriously affects the safe and stable operation of the units. For the aforementioned abnormal vibration and noise, there is currently a lack of effective fault diagnosis methods, and existing research tends to be theoretical research, and there is no disposal method that can be given to solve it. Summary of the invention

[0003] In order to solve the technical problem that there is only theoretical research on abnormal vibration and noise at present, but there is a lack of practical and effective fault diagnosis methods to deal with the fault diagnosis and treatment of abnormal vibration and noise generated by bearings, the present invention provides a valve fault diagnosis and treatment method for coal-fired power units. By analyzing the vibration frequency of the turbine and combining the existing resonance theory to determine the cause of the vibration, corresponding treatment is carried out to reduce vibration and noise, improve the reliability of the unit operation, and ensure safe and stable operation of the unit.

[0004] The present invention solves the technical problem by adopting a technical solution: a method for diagnosing and treating valve faults of coal-fired power plants, which is characterized by comprising the following steps:

[0005] (1) measuring a vibration spectrum fv of the steam turbine, wherein the vibration spectrum is a shaft vibration spectrum or a bearing vibration spectrum;

[0006] (2) Analyze the vibration spectrum fv, and go to the next step when the vibration spectrum fv>50Hz;

[0007] (3) Test the valve noise frequency fc, bearing natural frequency fb and spring box natural frequency ft;

[0008] (4) Calculate the ratio of the vibration spectrum fv and the valve noise frequency fc, and go to the next step when fv / fc∈(0.85~1.15);

[0009] (5) Compare the vibration spectrum fv and the natural frequency ft of the spring box, and go to the next step when fv≤ft;

[0010] (6) Calculate the ratio of the vibration spectrum fv and the bearing natural frequency fb, and go to the next step when the ratio fv / fb is ≥0.85;

[0011] (7) The fault is diagnosed as high-frequency intermittent exciting force, and can be handled by valve activity test, and then go to the next step;

[0012] (8) Adjust the verticality of the spring box;

[0013] (9) Measure the vibration value of the bearing vibration and end when the vibration value is less than 3.8mm / s.

[0014] The present invention measures the vibration spectrum of the steam turbine, especially when the vibration frequency of the steam turbine is a high frequency higher than 50Hz. Since the high-frequency vibration mainly comes from uneven exciting forces such as valve failure, steam flow pulsation, flash evaporation, etc., it is generally accompanied by high-frequency noise. The main reason for the high-frequency vibration of the valve is that the unstable high-frequency exciting force increases and excites the resonance of the valve system, and excites the high-frequency noise to be transmitted to the surface of the bearing, thereby causing the bearing to resonate slightly. At this time, by measuring and collecting the valve noise frequency, the natural frequency of the bearing and the natural frequency of the spring box, and then comparing whether the ratio of fv / fc is within the set range, it can be Determine the probability of resonance, and then analyze the ratio of fv / ft and the ratio of fv / fb step by step, and diagnose that the source of the vibration fault is high-frequency intermittent exciting force, mainly the steam flow force in the flow part of the turbine or the valve. The full-stroke valve activity test (i.e., impact test) of the medium-pressure main steam valve and the medium-pressure regulating valve can be regularly performed through the valve pressure plate to improve the steam flow stability of the valve, reduce the structural vibration at the medium regulating valve, and thus reduce the noise here. Further adjustment of the verticality of the spring box can make the valve noise more significantly reduced, and the vibration value of the bearing vibration is reduced to the set threshold. In addition, in step (4), when the ratio of fv / fc exceeds the set set, it is diagnosed as other problems and does not need to be processed. The valve activity test is a prior art.

[0015] As a further improvement and supplement to the above technical solution, the present invention adopts the following technical measures: in the step (6), when the ratio of fv / fb is less than 0.85, the fault is diagnosed as the tilt of the spring support and the damage of the spring, and it can be solved by replacing the valve spring cylinder, and after the solution is completed, return to step (8).

[0016] When the ratio of fv / fb is less than 0.85, it indicates that the fault is caused by the deflection of the spring support and the damage of the spring, which can be solved by replacing a new valve spring cylinder.

[0017] Preferably, in step (9), when the vibration value is ≥3.8 mm / s, the process returns to step (6).

[0018] When the vibration value of the bearing is still greater than the set value, return to step (6) to calculate the ratio of the vibration spectrum and the natural frequency of the bearing.

[0019] Preferably, when fv > ft in step (5), the diagnosed fault is the influence of pipeline air flow, and it can be disposed of by adjusting the pipeline connection.

[0020] When fv > ft, it indicates that the vibration is caused by the pipeline. Because the instability of the pipeline flow field will induce high-frequency exciting forces. When high-temperature and high-pressure steam passes through the valve, due to the change of the flow channel shape, the state of the steam changes, resulting in turbulence and eddy currents. During actual operation, the throttling process of the steam in the valve will cause it to be subjected to friction, resistance and various disturbances, and then generate different forms of vortex flows, making the pipeline flow field unstable. This kind of fault can be solved by adjusting the pipeline connection. Adjusting the pipeline connection includes strengthening and adding existing pipeline supports, aiming to strengthen the support and fixation of the pipeline.

[0021] Preferably, when the vibration frequency spectrum fv ≤ 50 Hz in step (2), go to step (2-1);

[0022] (2-1) Measure the vibration value of the valve. When the vibration value < 125 μm, go to step (2-2);

[0023] (2-2) Measure the vibration frequency spectrum of the valve to diagnose the fault. When the vibration frequency spectrum of the valve is the power frequency, the diagnosed fault is rotor mass imbalance, and dynamic balance adjustment is carried out; when the vibration frequency spectrum of the valve is the half-frequency, the diagnosed fault is oil film whirl or steam flow excitation, and adjust the oil pressure, oil temperature and bearing bush structure.

[0024] When fv ≤ 50 Hz, continue to measure the vibration value of the valve. When it is less than the set threshold value, it can be determined that the vibration is small. Then, according to the frequency spectrum analysis, if it is the power frequency, it is diagnosed as a rotor fault, specifically rotor mass imbalance, and dynamic balance adjustment is required; if it is the half-frequency, it is diagnosed as oil film whirl or steam flow excitation, and adjust the oil pressure, oil temperature and bearing bush structure.

[0025] Preferably, when the vibration value ≥ 125 μm in step (2-1), go to the next step (2-3);

[0026] (2-3) Measure the natural frequency of the valve to judge the resonance risk interval. Measure the natural frequency fd of the valve and compare it with the vibration frequency spectrum fv. When fd / fv ∈ (0.85 - 1.15), diagnose the resonance risk interval as ±X% of the resonance frequency, 10 ≤ X ≤ 15, and adjust through step (2-4) to avoid the resonance risk interval;

[0027] (2-4) The adjustment includes adjusting the pipeline, adjusting the valve spring and adjusting the load distribution of the cylinder block in sequence. After adjusting the load distribution of the cylinder block, return to step (2-1).

[0028] When the valve vibration value is large and meets the standard or even exceeds the set threshold, the ratio of the valve natural frequency and the vibration spectrum is further compared, and based on this, the resonance theory is combined to diagnose and divide the risk interval that will produce resonance, and then the pipeline, valve spring and cylinder load distribution are adjusted in sequence to avoid the resonance risk interval. Adjusting the pipeline can be to reinforce and add existing pipeline brackets to strengthen the support and fixation of the pipeline; adjusting the valve spring is specifically to adjust the spring body vertically.

[0029] Preferably, the value of X in step (2-3) is 15. By selecting the maximum value in the value range of X, the resonance risk range that needs to be guarded against is expanded, risk control is further tightened, and the resonance risk is reduced.

[0030] The beneficial technical effect of the present invention is as follows: the vibration of the steam turbine is measured to obtain the vibration spectrum, and then the analysis is carried out, and the cause of the vibration is determined in combination with the resonance theory of the prior art, and different adjustments are made accordingly to reduce the vibration and noise, and improve the reliability of the unit operation. The adjustment method can be a variety of measures such as adjusting the pipeline connection and the valve spring, cylinder load distribution, or replacing the valve spring cylinder (corresponding to the valve spring support), valve activity test and spring box verticality (corresponding to the inclination of the valve spring support). BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 : Schematic diagram of the process of the present invention.

[0032] Figure 2 : Axial vibration spectrum diagram of the medium-pressure regulating oil motor on side B of unit described in Invention Application Case 1.

[0033] Figure 3 : Schematic diagram of the process of Example 1.

[0034] Figure 4 : The 3-watt vibration trend diagram of Unit 7 described in Invention Application Case 2.

[0035] Figure 5 : The 3-watt vibration spectrum of Unit 7 described in Invention Application Case 2.

[0036] Figure 6 : Schematic diagram of frequency response described in invention application case 2.

[0037] Figure 7 : Schematic diagram of the process of Example 2. DETAILED DESCRIPTION

[0038] The present invention will be further described below in conjunction with the accompanying drawings and specific implementation methods.

[0039] like Figure 1As shown, the present invention is a method for diagnosing and treating valve faults of coal-fired power units, comprising the following steps:

[0040] (1) measuring the vibration spectrum fv of the steam turbine, wherein the vibration spectrum is a shaft vibration spectrum or a bearing vibration spectrum, and then proceeding to step (2);

[0041] (2) Analyze the vibration spectrum fv, and go to step (3) when the vibration spectrum fv>50Hz; go to step (2-1) when the vibration spectrum fv≤50Hz;

[0042] (2-1) Measure the vibration value of the valve, and when the vibration value is less than 125 μm, proceed to step (2-2); when the vibration value is greater than or equal to 125 μm, proceed to step (2-3);

[0043] (2-2) Measure the valve vibration spectrum to diagnose faults. When the valve vibration spectrum is at the power frequency, diagnose the fault as a rotor fault caused by rotor mass imbalance, and perform dynamic balancing adjustment. When the valve vibration spectrum is at half the frequency, diagnose the fault as oil film vortex or steam flow excitation, and adjust the oil pressure, oil temperature and bearing structure.

[0044] (2-3) Measure the valve natural frequency to determine the resonance risk interval, measure the valve natural frequency fd and compare it with the vibration spectrum fv, and diagnose the resonance risk interval as ±X% of the resonance frequency when fd / fv∈(0.85-1.15), 10≤X≤15, and adjust through step (2-4) to avoid the resonance risk interval. In this embodiment, the preferred value of X is 15;

[0045] (2-4) The adjustment includes adjusting the pipeline, adjusting the valve spring and adjusting the cylinder load distribution in sequence, and returning to step (2-1) after the cylinder load distribution is adjusted;

[0046] (3) Test the valve noise frequency fc, the bearing natural frequency fb and the spring box natural frequency ft, and go to step (4);

[0047] (4) Calculate the ratio of the vibration spectrum fv and the valve noise frequency fc, and go to step (5) when fv / fc∈(0.85~1.15);

[0048] (5) Compare the vibration spectrum fv and the natural frequency ft of the spring box. When fv≤ft, go to step (6); when fv>ft, diagnose the fault as the influence of pipeline steam flow, and it can be handled by adjusting the pipeline connection;

[0049] (6) Calculate the ratio of the vibration spectrum fv and the bearing natural frequency fb. When the ratio of fv / fb is ≥0.85, go to step (7). When the ratio of fv / fb is less than 0.85, the fault is diagnosed as the tilt of the spring support and the damage of the spring, which can be solved by replacing the valve spring cylinder. After the solution is completed, go back to step (8).

[0050] (7) The fault is diagnosed as high-frequency intermittent exciting force, and can be handled by valve activity test, go to step (8);

[0051] (8) Adjust the verticality of the spring box and go to step (9);

[0052] (9) Measure the vibration value of the bearing vibration, and end when the vibration value is less than 3.8 mm / s. When the vibration value is greater than or equal to 3.8 mm / s, return to step (6).

[0053] The present invention measures the vibration of the steam turbine to obtain the vibration spectrum, then analyzes it, and combines the resonance theory of the prior art to determine the cause of the vibration, and accordingly performs different adjustments and treatments to reduce vibration and noise, thereby improving the reliability of the operation of the coal-fired power unit.

[0054] The present invention is explained in conjunction with practical application cases.

[0055] Case 1: During the operation of Unit 1 of a certain plant in December 2019, it was found that the operating platform near the medium-pressure cylinder had obvious vibration. The medium-pressure valve group was tested with a handheld vibration meter, and it was found that the medium-pressure main steam valve, the main body of the regulating valve and the end of the oil motor all vibrated greatly, among which the maximum vibration value of the medium-pressure regulating valve exceeded 500μm, affecting the safe operation of the unit.

[0056] In the first step, the maximum value of the shaft vibration of the turbine medium-pressure rotor support bearing 3 is 50μm, and it remains basically unchanged, not fluctuating with the random group load fluctuation, and the frequency is 50Hz.

[0057] In the second step, the vibration of the medium-pressure main steam valve and the oil motor at the end of the regulating valve body was analyzed. It was found that the vibration of the medium-pressure valves on both sides was large, as shown in the following: the vibration of the medium-pressure valve on the B side was greater than that of the medium-pressure valve on the A side, and the vibration of the medium-pressure regulating valve on the B side was greater than that of the medium-pressure main steam valve on the B side. The axial vibration of the medium-pressure regulating valve on the B side was the largest in the three directions, with a vibration value of 545μm. The frequency spectrum was dominated by the 50Hz component, satisfying the vibration spectrum fv≤50Hz, and the valve vibration was ≥125μm, see Table 1 and Figure 2 .

[0058] Table 1 below is a list of vibration data of the medium-pressure valve end oil motor (unit: μm).

[0059]

[0060] Table 1

[0061] The third step is to conduct a knock test on the medium-pressure valve of Unit 5 to test its natural frequency during the unit's outage on January 20, 2020. The first-order natural frequency of the medium-pressure valve of Unit 5 is closer to the unit speed frequency of 50Hz, and fd / fv is about 1, satisfying fd / fv∈(0.85~1.15), especially the medium-pressure regulating valve, indicating that the medium-pressure valve has structural resonance, see Table 2.

[0062] Table 2 below is a list of the natural frequency tests for the medium-pressure main steam and regulating valve ends of Unit 5.

[0063]

[0064] Table 2

[0065] The fourth step is to check the supports and hangers of the reheat steam pipes, extraction pipes, etc. related to the intermediate pressure cylinder. It was found that a small number of variable force spring supports and hangers had problems such as under- or over-compression, damper failure, and contact between the cross arm and the ground of the spring hanger. This shows that the stress condition of the relevant pipelines is good. In addition, the reheat section pipeline near the intermediate pressure cylinder did not show obvious vibration in the previous operation. It can be judged that although the position of the reheat pipeline is close to the interface of the intermediate pressure cylinder of the unit, it has little effect on the thrust of the intermediate pressure cylinder cylinder port. Therefore, the influence of the pipeline and the supports and hangers on the intermediate pressure cylinder body is ruled out. At this time, the pipeline vibration is very small, and the adjustment of the pipeline can be omitted.

[0066] The fifth step is to increase the preload force and uniformity of the valve group spring, and adjust the initial cold compression of the four spring brackets under the center adjustment door from 197568N to 216384N, that is, adjust the spring compression in the cold state to the compression in the hot state. The spring compression in the hot state will be further increased to increase the support reaction force of the spring support, while ensuring that the lifting heights of the four spring brackets are basically consistent.

[0067] The sixth step is the medium pressure cylinder load distribution test. The medium pressure cylinder body load distribution is re-optimized and adjusted. After the treatment, the unit is started to 980MW, the 3-wafer shaft vibration is 37μm, the bearing vibration is 1.5mm / s, the medium pressure main steam valve and the regulating valve have the largest horizontal vibration, which is 85μm, and the axial vibration is 35μm, and the vertical vibration of the medium pressure cylinder cat claw support is reduced to less than 10μm. The following table 3 is the load distribution list before and after the medium pressure cylinder capacity expansion and transformation.

[0068]

[0069] Table 3

[0070] Table 4 below is a list of medium pressure valve vibration data (unit: μm)

[0071]

[0072] Table 4

[0073] After the treatment, the vibration of the unit's medium-pressure valve was effectively controlled, and its axial vibration was reduced from 545μm at the initial stage of the fault to 35μm, with a significant decrease in vibration, meeting the valve vibration of <125μm. In actual application, when the valve vibration is less than 80μm, it is considered that the vibration problem has been properly solved, and it is no longer necessary to measure the valve vibration spectrum to diagnose the fault and take corresponding measures; if the valve vibration is ≥80μm, continue to measure the valve vibration spectrum to diagnose the fault, and make adjustments according to the operating frequency or half frequency. When the valve vibration spectrum is at the half frequency, diagnose the rotor mass imbalance and make dynamic balance adjustments. When the valve vibration spectrum is at the half frequency, diagnose the oil film vortex or steam flow excitation, and adjust the oil pressure, oil temperature and bearing structure.

[0074] The process of Case 1 above is as follows Figure 3 shown.

[0075] Case 2: Since May 4, 2020, after the load of Unit 7 was increased to 950MW, obvious noise appeared at the steam inlet valves of the high-pressure cylinder and the medium-pressure cylinder. The vibration of the 2-4 watts increased rapidly and then decreased. The vibration of the 3 watts had the largest jump amplitude, jumping from 3.5mm / s to 7mm / s, and even 9mm / s; the vibration of the 3 watts fluctuated between 1mm / s and 4mm / s. Figure 4 The 3-watt vibration spectrum of Unit 7 is shown, and Figure 5 The 3-watt vibration spectrum of Unit 7 is shown.

[0076] The first step is to analyze the vibration spectrum. The bearing vibration spectrum contains high-frequency components of 382.5Hz and 765Hz. The main frequency is 382.5Hz as fv, which satisfies fv>50Hz, and the other components remain basically unchanged. The shaft vibration changes slightly, and the power frequency component of the bearing vibration changes slightly, indicating that the turbine body has not deteriorated. As shown in Table 5, the natural frequency of the spring support of the north high-pressure main steam valve and the regulating valve is subjected to a pulse impact test. The natural frequency of the spring support here is the natural frequency of the spring box ft. The following Table 5 is a list of the natural frequencies of the spring support of Unit 6 (frequency / Hz).

[0077]

[0078] Table 5

[0079] In the second step, the noise power spectrum analysis was performed on the valve sound, and it was found that there was a high-frequency component of 382.5Hz. The pulse impact test was performed on the natural frequency of the unit 1-3 watts, and its first-order resonance frequency was measured to be 250Hz and 350Hz respectively. Its natural frequency is shown in Table 6, and the frequency response function curve is shown in Figure 6 As shown below.

[0080] Table 6 is a list of the 3-watt resonant frequencies of the unit.

[0081]

[0082] Table 6

[0083] The natural frequencies fb of the first few orders of 3W include 166.8Hz, 340.3Hz, and 398.1Hz, which are close to the natural frequencies of the spring supports of the high-pressure main steam valve and the regulating valve. If there is a fault in the spring supports of the main steam valve and the regulating valve, it is easy to induce the vibration of the spring supports, resulting in high-frequency resonance of 2 and 3W; similarly, if there is a fault in the medium-pressure main valve or the medium-pressure regulating valve, it is also easy to cause high-frequency vibration, inducing a large jump in the vibration of 3W.

[0084] The third step, when there is an abnormal sound and vibration fault, the minimum measured vibration frequency fc of the bearing is 382.5Hz, which is close to the 3rd order natural frequency of the spring support 389.0Hz, and other frequencies are greater than the natural frequency of the spring. The natural frequency of the bearing is 340Hz, and the possibility of spring damage is relatively high. In this embodiment, fv>50Hz, and satisfies fv / fc∈(0.85~1.15); compare the three ft corresponding to the third order in Table 5 with fv one by one. When fv>ft, the fault is diagnosed as the influence of pipeline steam flow, which can be solved by adjusting the pipeline connection. When fv≤ft, compare the ratios of fv and the aforementioned fb one by one, and proceed to the following fourth step when fv / fb<0.85 is satisfied.

[0085] The fourth step is to stop the machine for inspection, replace the valve spring cylinder, and adjust the verticality of the spring box. After replacement, the vibration of the 2nd and 3rd valves is stabilized at 1.2mm / s and 1.8mm / s respectively, and the adjustment effect reaches the vibration of the valve <3.8mm / s, which can save the step of adjusting the verticality of the spring box in the present invention.

[0086] The process of Case 2 above is as follows Figure 7 In addition, in the third step, if fv / fb≥0.85, the valve activity test (i.e., impact test) is carried out to improve the steam flow stability of the valve, reduce vibration and noise, and further adjust the verticality of the spring box to reduce the valve noise more significantly. The test ends when the vibration value of the bearing vibration is reduced to the set threshold.

Claims

1. A method for diagnosing and treating valve faults of coal-fired power plants, characterized in that The following steps are involved: (1) measuring a vibration spectrum fv of the steam turbine, wherein the vibration spectrum is a shaft vibration spectrum or a bearing vibration spectrum; (2) Analyze the vibration spectrum fv, and go to the next step when the vibration spectrum fv>50Hz; (3) Test the valve noise frequency fc, bearing natural frequency fb and spring box natural frequency ft; (4) Calculate the ratio of the vibration spectrum fv and the valve noise frequency fc, and go to the next step when fv / fc∈(0.85~1.15); (5) Compare the vibration spectrum fv and the natural frequency ft of the spring box, and go to the next step when fv≤ft; (6) Calculate the ratio of the vibration spectrum fv and the bearing natural frequency fb, and go to the next step when the ratio fv / fb is ≥0.85; (7) The fault is diagnosed as high-frequency intermittent exciting force, and can be handled by valve activity test, and then go to the next step; (8) Adjust the verticality of the spring box; (9) Measure the vibration value of the bearing vibration and end when the vibration value is less than 3.8mm / s.

2. The method for diagnosing and treating valve faults of coal-fired power plants according to claim 1 is characterized in that In step (6), when the ratio of fv / fb is less than 0.85, the fault is diagnosed as the tilt of the spring support and the damage of the spring, which can be solved by replacing the valve spring cylinder. After the solution is completed, return to step (8).

3. The method for diagnosing and treating valve faults of coal-fired power plants according to claim 1 or 2, characterized in that In step (9), when the vibration value is ≥3.8 mm / s, return to step (6).

4. The method for diagnosing and treating valve faults of coal-fired power plants according to claim 1 is characterized in that In step (5), when fv>ft, the fault is diagnosed as the influence of pipeline steam flow and can be handled by adjusting the pipeline connection.

5. The method for diagnosing and treating valve faults of coal-fired power plants according to claim 1 is characterized in that In the step (2), when the vibration spectrum fv≤50Hz, go to step (2-1); (2-1) Measure the vibration value of the valve, and when the vibration value is less than 125 μm, go to step (2-2); (2-2) Measure the valve vibration spectrum to diagnose faults. When the valve vibration spectrum is at the industrial frequency, diagnose the fault as rotor mass imbalance and perform dynamic balancing adjustment. When the valve vibration spectrum is at half the frequency, diagnose the fault as oil film vortex or steam flow excitation and adjust the oil pressure, oil temperature and bearing structure.

6. The method for diagnosing and treating valve faults of coal-fired power plants according to claim 5 is characterized in that In the step (2-1), when the vibration value is ≥125 μm, proceed to the next step (2-3); (2-3) Measure the valve natural frequency to determine the resonance risk interval, measure the valve natural frequency fd and compare it with the vibration spectrum fv, and diagnose the resonance risk interval as ±X% of the resonance frequency when fd / fv∈(0.85~1.15), 10≤X≤15, and adjust through step (2-4) to avoid the resonance risk interval; (2-4) The adjustment includes adjusting the pipeline, adjusting the valve spring and adjusting the cylinder load distribution in sequence, and returning to step (2-1) after the cylinder load distribution is adjusted.

7. The method for diagnosing and treating valve faults of coal-fired power plants according to claim 6 is characterized in that The value of X in the step (2-3) is 15.

Images